WO2018128455A1

WO2018128455A1 - Method and apparatus for random access in wireless communication systems

Info

Publication number: WO2018128455A1
Application number: PCT/KR2018/000243
Authority: WO
Inventors: Yingjie Zhang; Bin Yu; Chen QIAN; Qi XIONG; Jingxing Fu; Di SU
Original assignee: Samsung Electronics Co., Ltd.
Priority date: 2017-01-06
Filing date: 2018-01-05
Publication date: 2018-07-12
Also published as: CN108282902B; CN108282902A

Abstract

The present disclosure relates to a pre-5^th-Generation (5G) or 5G communication system to be provided for supporting higher data rates beyond 4^th-Generation (4G) communication system such as long term evolution (LTE). A method for operating a base station in a wireless communication system is provided. The method includes determining a transmission beam of a terminal based on a preamble sequence received from the terminal, determining, an identifier for the transmission beam based on a preset mapping relationship, and transmitting, to the terminal, a random access response comprising the identifier for the transmission beam.

Description

METHOD AND APPARATUS FOR RANDOM ACCESS IN WIRELESS COMMUNICATION SYSTEMS

This disclosure relates generally to wireless communication systems. More specifically, this disclosure relates to a method and an apparatus for random access in wireless communication systems.

To meet the demand for wireless data traffic having increased since deployment of 4^th generation (4G) communication systems, efforts have been made to develop an improved 5^th generation (5G) or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a 'Beyond 4G Network' or a 'Post Long Term Evolution (LTE) System'.

The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 28GHz or 60GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G communication systems.

In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud Radio Access Networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), reception-end interference cancellation and the like.

In the 5G system, Hybrid frequency shift keying (FSK) and quadrature amplitude modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.

The rapid development of information industry, particularly the increasing demand from the mobile Internet and the Internet of Things (IoT), brings about unprecedented challenges in the future mobile communications technology. According to the ITU-R M. [IMT.BEYOND 2020. TRAFFIC] issued by the International Telecommunication Union (ITU), it can be expected that, by 2020, mobile services traffic will grow nearly 1,000 times as compared with that in 2010 (4G era), and the number of user equipment connections will also be over 17 billion, and with a vast number of IoT devices gradually expand into the mobile communication network, the number of connected equipments will be even more astonishing. In response to this unprecedented challenge, the communications industry and academia have prepared for 2020s by launching an extensive study of the fifth generation of mobile communications technology (5G). Currently, in ITU-R M. [IMT.VISION] from ITU, the framework and overall objectives of the future 5G have been discussed, where the demands outlook, application scenarios and various important performance indexes of 5G have been described in detail. In terms of new demands in 5G, the ITU-R M. [IMT. FUTURE TECHNOLOGY TRENDS] from ITU provides information related to the 5G technology trends, which is intended to address prominent issues such as significant improvement on system throughput, consistency of the user experience, scalability so as to support IoT, delay, energy efficiency, cost, network flexibility, support for new services and flexible spectrum utilization, etc.

A random access process, as an important step in a wireless communication system, is used for establishing downlink synchronization and uplink synchronization between a UE and a base station and for allocating, by the base station and to the UE, an ID for identifying a user, etc. The performance of initial access and random access directly influences the UE's experience. Wherein, for a conventional wireless communication system, for example, in LTE and LTE-Advanced, the random access process is used in various scenarios such as establishment of an initial link, cell handover, reestablishment of an uplink and RRC connection reestablishment, and is classified into contention-based random access and contention-free random access depending upon whether a UE exclusively occupies preamble sequence resources. Since, for the contention-based random access, each UE selects a preamble sequence from same preamble sequence resources when trying to establish an uplink, there may be a case in which a multiple of UEs select and transmit a same preamble sequence to the base station. Therefore, the collision resolution mechanism becomes an important research direction in the random access. How to reduce the probability of collision and how to quickly solve a collision that has occurred are key indicators influencing the random access performance.

Usually, the contention-based random access process includes four steps, as shown in FIGURE 5. Before the start of the random access process, the base station transmits configuration information of the random access process to the user equipment and the user equipment performs the random access process according to the received configuration information. In the first step, the user randomly selects a preamble sequence from a preamble sequence resource pool and transmits the preamble sequence to a base station. The base station performs correlation detection on the received signal, so as to identify the preamble sequence transmitted by the user. In the second step, the base station transmits a Random Access Response (RAR) to the user. The RAR contains an identifier of a random access preamble sequence, a timing advance instruction determined according to an estimated time delay between the UE and the base station, a Temporary Cell-Radio Network Temporary Identifier (TC-RNTI), and time-frequency resources allocated for the UE to perform uplink transmission next time. In the third step, the user transmits a Message 3 (Msg3) to the base station according to the information in the RAR. The Msg3 contains information such as a UE identifier and an RRC link request, wherein the UE identifier is an identifier that is unique to the user and used for resolving a collision. In the fourth step, the base station transmits a collision resolution identifier to the user, the collision resolution identifier containing an identifier of a UE who wins in the collision resolution. The user upgrades TC-RNTI to Cell-Radio Network Temporary Identifier (C-RNTI) upon detecting its own identifier, and transmits an Acknowledgement (ACK) signal to the base station to complete the random access process and then waits for the scheduling of the base station. Otherwise, the user will start a new random access process after a certain delay.

It is to be noted that, in the second step, the random access response is transmitted through a physical downlink shared channel. During the transmission, the base station scrambles a physical downlink control channel corresponding to the physical downlink shared channel by using a Random Access-Radio Network Temporary Identity (RA-RNTI). The RA-RNTI is in one-to-one correspondence to time-frequency resources occupied by the transmission of the preamble sequence detected by the base station. In this case, the user can calculate a corresponding RA-RNTI and descramble the physical downlink control channel by using the identifier to further detect the random access response.

For a contention-free random access process, since the base station has known the identifier of the user, the base station can allocate a preamble sequence to the user. Thus, when transmitting a preamble sequence, the user does not need to randomly select a sequence, and instead, it will use the allocated preamble sequence. Upon detecting the allocated preamble sequence, the base station will transmit a corresponding random access response, the random access response including information such as timing advance and uplink resource allocation. Upon receiving the random access response, the user considers that the uplink synchronization has been completed, and then waits for the further scheduling of the base station. Therefore, the initial access process and the contention-free random access process contain only two steps: a step 1 of transmitting a preamble sequence, and a step 2 of transmitting a random access response.

The millimeter wave communication is a possible key technology in 5G. By improving the carrier frequency to millimeter wavebands, the available bandwidth will be increased greatly, so that the transmission rate of the system can be improved greatly. In order to resist against characteristics such as high fading and high loss in a wireless channel at millimeter wavebands, a millimeter wave communication system generally centralizes beam energy in a certain direction by beamforming, i.e., by using a weighting factor. During the wireless communication, a base station and a user search for an optimal beam pair by polling or in other ways, so that the received signal-to-noise ratio on both the base station side and the user side is maximized. Since the user and the base station have no idea of the direction of the optimal beam pair when an initial link is established, random access in the millimeter-wave communication systems encounters great challenges.

To obtain a transmitting beamforming direction for the user side, a possible way is that the user attempts all possible beams in the step 1 of transmitting a preamble sequence by conventional polling or differential polling; and the base station detects an optimal transmitting beamforming direction according to information such as the strength of the received signal, and transmits, in the step 2 of transmitting a random access response, an indication of the optimal beamforming direction to the user.

In the existing solutions, usually by means of explicit indication, the indicated user transmitting beam No., the transmitting beam index or the transmitting beam direction deviation index are directly contained in the random access response which is then transmitted to the user. In this case, on the basis of the existing contents, it is necessary to add extra bits to the random access response to transmit the indicated beam information. When there are many user transmitting beamforming directions, the corresponding random access response overhead will be significantly increased and the system performance will be degraded. In addition, when different users have a different number of transmitting beam directions, the number of bits to be added to the random access responses for different user is also different. In this case, if random access responses of different lengths are transmitted to different users, the signaling overhead will be significantly increased. However, if a random access response of a same length is transmitted to different users, although the signaling overhead will not be significantly influenced, the length of the random access response must be subject to a user having a largest number of transmitting beam directions. Such a length is unnecessary for a user having a small number of transmitting beam directions. As a result, the resource overhead will be further increased.

Embodiments of the present disclosure provide a method and an apparatus for random access in wireless communication systems.

Embodiments of the present disclosure provide a random access method in wireless communication systems to solve the problems of increased resource overhead and degraded system performance in the prior art, which are resulted from the indication of an optimal beamforming direction during the random access process in a millimeter wave communication system.

In one embodiment, a method in a wireless communication system provided. The method includes the following steps of: receiving, by a base station, a preamble sequence transmitted by a user equipment, determining a transmitting beam direction with the maximum energy based on the preamble sequence; determining, in accordance with a preset mapping relationship, an indication identifier to which the transmitting beam direction with the maximum energy is mapped, transmitting a random access response containing the indication identifier to the user equipment, and receiving a signal transmitted by the user equipment in the transmitting beam direction with the maximum energy.

Preferably, the indication identifier is an RA-RNTI, and the step of transmitting a random access response containing the indication identifier to the user equipment includes scrambling a downlink control channel by using the RA-RNTI, and transmitting a random access response to the user equipment by a downlink shared channel corresponding to the downlink control channel.

Preferably, the step of receiving, by the base station, a preamble sequence transmitted by the user equipment includes receiving, by the base station, a preamble sequence transmitted by the user equipment based on a single antenna port or multiple antenna ports.

Preferably, when the base station receives the preamble sequence transmitted by the user equipment based on a single antenna port, the preset mapping relationship is a mapping relationship from a transmitting beam direction, time resource occupied by random access channel and frequency resource occupied by random access channel to the RA-RNTI, and the step of determining, in accordance with a preset mapping relationship, an indication identifier to which the transmitting beam direction with the maximum energy is mapped includes determining, in accordance with the mapping relationship, an RA-RNTI to which the transmitting beam direction with the maximum energy, the time resource occupied by random access channel and frequency resource occupied by random access channel are mapped.

Preferably, when the base station receives the preamble sequence transmitted by the user equipment based on multiple antenna ports, the preset mapping relationship is a mapping relationship from a transmitting beam direction, a deviation of the transmitting beam direction and time-frequency resources occupied by random access channel to the RA-RNTI, and the step of determining, in accordance with a preset mapping relationship, an indication identifier to which the transmitting beam direction with the maximum energy is mapped includes determining, in accordance with the mapping relationship, an RA-RNTI to which the transmitting beam direction with the maximum energy, a deviation of the transmitting beam direction with the maximum energy and the time-frequency resources occupied by random access channel are mapped.

Preferably, before the step of determining, in accordance with the mapping relationship, an RA-RNTI to which the transmitting beam direction with the maximum energy, a deviation of the transmitting beam direction with the maximum energy and the time-frequency resources occupied by random access channel are mapped, the method further includes determining, based on a result of sum beam sequence correlation detection and a result of differential beam sequence correlation detection corresponding to the preamble sequence, a deviation of the transmitting beam direction with the maximum energy.

Preferably, the preset mapping relationship is a mapping relationship between a random access channel time resource and a random access channel frequency resource both used in the transmitting beam direction, and the random access-radio network temporary identifier; and the step of determining, in accordance with the preset mapping relationship, an indication identifier to which the transmitting beam direction with the maximum energy is mapped includes determining, in accordance with the mapping relationship, an RA-RNTI to which the random access channel time resource and the random access channel frequency resource both used in the transmitting beam direction with the maximum energy are mapped.

Preferably, the indication identifier is a cell-radio network temporary identifier (C-RNTI), and the step of transmitting a random access response containing the indication identifier to the user equipment includes determining a cell where the user equipment is located, and selecting, from a subset of C-RNTIs for the cell, an unused C-RNTI to transmit a random access response containing the selected C-RNTI to the user equipment.

Preferably, the step of receiving, by the base station, a preamble sequence transmitted by the user equipment comprises: receiving, by the base station, a preamble sequence transmitted by the user equipment based on a single antenna port or multiple antenna ports.

Preferably, the preset mapping relationship is a mapping relationship between a transmitting beam direction and the C-RNTI, and the step of determining, in accordance with a preset mapping relationship, an indication identifier to which the transmitting beam direction with the maximum energy is mapped includes determining, in accordance with the mapping relationship, a C-RNTI to which the transmitting beam direction with the maximum energy is mapped, or, the preset mapping relationship is a mapping relationship from a transmitting beam direction and a deviation of the transmitting beam direction to the C-RNTI, and the step of determining, in accordance with a preset mapping relationship, an indication identifier to which the transmitting beam direction with the maximum energy is mapped includes determining, in accordance with the mapping relationship, a C-RNTI to which the transmitting beam direction with the maximum energy and the deviation of the transmitting beam direction with the maximum energy are mapped.

Preferably, before the step of receiving a preamble sequence transmitted by the user equipment, the method further includes transmitting system configuration information to the user equipment, the configuration information comprising random access channel configuration information and also a mapping relationship between a transmitting beam direction and the indication identifier.

Preferably, the step of determining a transmitting beam direction with the maximum energy based on the preamble sequence includes determining a transmitting beam direction with the maximum energy based on a result of correlation detection performed on the preamble sequence.

In another embodiment, a method in a wireless communication system provided. The method includes the following steps of: transmitting, by a user equipment, a preamble sequence to the base station, receiving a random access response containing an indication identifier, which is transmitted by the base station; determining, in accordance with a preset mapping relationship, a transmitting beam direction with the maximum energy mapped to the indication identifier, and transmitting a signal to the base station in the transmitting beam direction with the maximum energy.

Preferably, the indication identifier is an RA-RNTI, and the step of receiving a random access response containing the indication identifier, which is transmitted by the base station, includes calculating an RA-RNTI used for scrambling a downlink control channel, and descrambling the downlink control channel by using the RA-RNTI to receive the random access response.

Preferably, the step of transmitting, by the user equipment, a preamble sequence to the base station includes transmitting, by the user equipment, a preamble sequence to the base station based on a single antenna port or multiple antenna ports.

Preferably, when the user equipment transmits a preamble sequence to the base station based on a single antenna port, the preset mapping relationship is a mapping relationship from a transmitting beam direction, time resource occupied by random access channel and frequency resource occupied by random access channel to the RA-RNTI, and the step of determining, in accordance with a preset mapping relationship, a transmitting beam direction with the maximum energy mapped to the indication identifier includes determining, in accordance with the mapping relationship, a transmitting beam direction with the maximum energy mapped to the RA-RNTI.

Preferably, when the user equipment transmits a preamble sequence to the base station based on multiple antenna ports, the preset mapping relationship is a mapping relationship from a transmitting beam direction, a deviation of the transmitting beam direction and time-frequency resources occupied by random access channel to the RA-RNTI; and the step of determining, in accordance with a preset mapping relationship, a transmitting beam direction with the maximum energy mapped to the indication identifier includes determining, in accordance with the mapping relationship, a transmitting beam direction with the maximum energy mapped to the RA-RNTI.

Preferably, the preset mapping relationship is a mapping relationship between a random access channel time resource and a random access channel frequency resource both used in the transmitting beam direction, and the RA-RNTI, and the step of determining, in accordance with the preset mapping relationship, a transmitting beam direction with the maximum energy mapped to the indication identifier includes determining, in accordance with the mapping relationship, a random access channel time resource and a random access channel frequency resource to which the RA-RNTI is mapped, and then determining a transmitting beam direction with the maximum energy using the random access channel time resource and the random access channel frequency resource.

Preferably, the indication identifier is a C-RNTI.

Preferably, the preset mapping relationship is a mapping relationship between a transmitting beam direction and the C-RNTI, and the step of determining, in accordance with a preset mapping relationship, a transmitting beam direction with the maximum energy mapped to the indication identifier includes determining, in accordance with the mapping relationship, a transmitting beam direction with the maximum energy mapped to the C-RNTI, or, the preset mapping relationship is a mapping relationship from a transmitting beam direction and a deviation of the transmitting beam direction to the C-RNTI, and the step of determining, in accordance with a preset mapping relationship, a transmitting beam direction with the maximum energy mapped to the indication identifier comprises: determining, in accordance with the mapping relationship, a transmitting beam direction with the maximum energy mapped to the C-RNTI.

Preferably, before the step of transmitting, by the user equipment, a preamble sequence to the base station, the method further includes receiving system configuration information transmitted by the base station, the configuration information comprising random access channel configuration information and also a mapping relationship between a transmitting beam direction and the indication identifier.

In yet another embodiment a base station in a wireless communication system provided. The base station includes a first receiving module configured to receive a preamble sequence transmitted by a user equipment, a first determination module configured to determine a transmitting beam direction with the maximum energy based on the preamble sequence, a second determination module configured to determine, in accordance with a preset mapping relationship, an indication identifier to which the transmitting beam direction with the maximum energy is mapped, a first transmitting module configured to transmit a random access response containing the indication identifier to the user equipment, and a second receiving module configured to receive a signal transmitted by the user equipment in the transmitting beam direction with the maximum energy.

In yet another embodiment, a user equipment in a wireless communication system provided. The user equipment includes a third transmitting module configured to transmit a preamble sequence to a base station; a third receiving module configured to receive a random access response containing an indication identifier, which is transmitted by the base station, a third determination module configured to determine, in accordance with a preset mapping relationship, a transmitting beam direction with the maximum energy mapped to the indication identifier, and a fourth transmitting module configured to transmit a signal to the base station in the transmitting beam direction with the maximum energy.

In yet another embodiment, a method for operating a base station in a wireless communication system is provided. The method includes determining a transmission beam of a terminal based on a preamble sequence received from the terminal, determining, an identifier for the transmission beam based on a preset mapping relationship, and transmitting, to the terminal, a random access response comprising the identifier for the transmission beam.

In yet another embodiment, a method for operating a terminal in a wireless communication system is provided. The method includes transmitting, to a base station, a preamble sequence, receiving, from the base station, a random access response comprising a identifier for a transmission beam, wherein the transmission beam is determined based on the preamble sequence, and wherein the identifier for the transmission beam is determined based on a preset mapping relationship.

In yet another embodiment, a base station (BS) in a wireless communication system is provided. The base station includes at least one processor configured to: determine a transmission beam of a terminal based on a preamble sequence received from the terminal, and determine, an identifier for the transmission beam based on a preset mapping relationship; and a transceiver configured to transmit, to the terminal, a random access response comprising the identifier for the transmission beam.

In yet another embodiment, a terminal in a wireless communication system is provided. The terminal includes at least one processor; and a transceiver configured to: transmit, to a base station, a preamble sequence, and receive, from the base station, a random access response comprising a identifier for a transmission beam, wherein the transmission beam is determined based on the preamble sequence, and wherein the identifier for the transmission beam is determined based on a preset mapping relationship.

A method and an apparatus according to various embodiments of the present disclosure allow to reduce the system overhead during the random access process, and greatly improve the performance of the random access process in a 5G communication system.

When in comparison with the conventional random access solution, in the solution of the embodiment, since an indication identifier mapped to a beamforming direction is contained in the random access response, no beam information such as the transmitting beam No., the transmitting beam index or the transmitting beam direction deviation is to be additionally provided, and thus, no more bits are to be added to transmit the indicated beam information. Accordingly, the system overhead is significantly reduced and the performance of the random access process in the 5G communication system is greatly improved.

Meanwhile, when different user equipments have a different total number of transmitting beam directions, the random access responses for different user equipments each contain an indication identifier having a uniform signaling length which will not change when the user equipments have a different total number of transmitting beam directions. Therefore, the signaling overhead can be greatly reduced, and the performance of the random access process in the 5G communication system can be further improved.

Additional aspects and advantages of the present disclosure will be partially appreciated and become apparent from the descriptions below, or will be well learned from the practices of the present disclosure.

For a more complete understanding of this disclosure and its advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:

FIGURE 1 illustrates a wireless communication system according to various embodiments of the present disclosure;

FIGURE 2 illustrates the BS in the wireless communication system according to various embodiments of the present disclosure;

FIGURE 3 illustrates the terminal in the wireless communication system according to various embodiments of the present disclosure;

FIGURE 4 illustrates the communication interface in the wireless communication system according to various embodiments of the present disclosure;

FIGURE 5 illustrates a schematic diagram of initial access and contention-based random access processes in LTE/LTE-A in the prior art;

FIGURE 6 illustrates a flowchart of a random access method according to various embodiments of the present disclosure;

FIGURE 7 illustrates a schematic diagram of the received energy of a sum beam and a differential beam according to various embodiments of the present disclosure;

FIGURE 8 illustrates a schematic diagram of a ratio of received signals of a differential beam and a sum beam according to various embodiments of the present disclosure;

FIGURE 9 illustrates a transmission structure of an antenna array according to various embodiments of the present disclosure;

FIGURE 10 illustrates a schematic diagram of UE-specified beam directions according to Embodiment 1 of the present disclosure;

FIGURE 11 illustrates an exemplary view showing a mapping relationship from the transmitting beam direction and the random access channel resource to the Random Access-Radio Network Temporary Identifier (RA-RNTI), according to Embodiment 1 of the present disclosure;

FIGURE 12 illustrates a schematic view of a frame structure when the UE adopts a single-port beam polling solution, according to Embodiment 1 of the present disclosure;

FIGURE 13 illustrates a schematic diagram of UE-specified beam pair directions according to Embodiment 2 of the present disclosure;

FIGURE 14 illustrates an exemplary view showing a mapping relationship form the transmitting beam direction, the deviation of the transmitting beam direction and the time-frequency resources occupied by random access channel to the RA-RNTI, according to Embodiment 2 of the present disclosure;

FIGURE 15 illustrates a schematic view of a frame structure when the UE adopts multi-port beam polling solution, according to Embodiment 2 of the present disclosure;

FIGURE 16 illustrates a flowchart of detecting a preamble sequence and a deviation of a transmitting beam direction by a base station, according to Embodiment 2 of the present disclosure;

FIGURE 17 illustrates an exemplary view showing a mapping relationship from the transmitting beam direction and the deviation of the transmitting beam direction to the cell-radio network temporary identifier (C-RNTI), according to Embodiment 3 of the present disclosure;

FIGURE 18 illustrates a schematic view of a frame structure when the UE adopts a beam polling solution, according to Embodiment 4 of the present disclosure;

FIGURE 19 illustrates an exemplary view showing a mapping relationship between the time-frequency resources occupied by random access channel and the RA-RNTI, according to Embodiment 4 of the present disclosure;

FIGURE 20 illustrates a flowchart of a random access method according to various embodiments of the present disclosure;

FIGURE 21 illustrates a flowchart of a random access method according to various embodiments of the present disclosure;

FIGURE 22 illustrates a flowchart of a random access method according to various embodiments of the present disclosure;

FIGURE 23 illustrates a flowchart of a random access method according to various embodiments of the present disclosure;

FIGURE 24 illustrates a structure diagram of a base station according to various embodiments of the present disclosure; and

FIGURE 25 illustrates a structure diagram of a user equipment according to various embodiments of the present disclosure.

To make the solutions of the present disclosure be understood by those skilled in the art better, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings.

In some flows as described in the description, claims and drawings of the present disclosure, many operations are contained which occur in a specific order. However, it should be appreciated that those operations may not be performed in a same order as that decreased herein or may be performed concurrently. The serial number of the operations, for example, 101, 102, etc., is merely used for distinguishing between the various operations, and the serial number itself does not represent any execution order. In addition, those flows may include more or less operations and those operations can be performed in order or concurrently. It is to be noted that terms "first", "second", etc., as used herein, are merely used for distinguishing between different messages, apparatuses, modules or more, without representing any order or defining that "first" and "second" belong to different types.

Besides, in the description, claims and some processes described in the above drawings, a plurality of mapping relations appeared in a particular order or direction are included. It should be understood that these mapping relations may not be executed in the order or direction described in the text, for example, the mapping relation from A to B can also refer to the mapping relation from B to A, that is, the mapping relation between A and B can be bidirectional.

The technical solutions in the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are merely some but not all of the embodiments of the present disclosure. All other embodiments obtained by a person of ordinary skill in the art on the basis of the embodiments of the present disclosure without paying any creative effort shall fall into the protection scope of the present disclosure.

Hereinafter, in various embodiments of the present disclosure, hardware approaches will be described as an example. However, various embodiments of the present disclosure include a technology that uses both hardware and software and thus, the various embodiments of the present disclosure may not exclude the perspective of software.

Hereinafter, the present disclosure describes technology for random access at base station and user equipment in a wireless communication system.

The terms referring to an identifier, the terms referring to a signal, the terms referring to a channel, the terms referring to control information, the terms referring to a network entity, and the terms referring to elements of a device used in the following description are used only for convenience of the description. Accordingly, the present disclosure is not limited to the following terms, and other terms having the same technical meaning may be used.

Further, although the present disclosure describes various embodiments based on the terms used in some communication standards (for example, 3rd Generation Partnership Project (3GPP)), they are only examples for the description. Various embodiments of the present disclosure may be easily modified and applied to other communication systems.

FIGURE 1 illustrates a wireless communication system according to various embodiments of the present disclosure. In FIGURE 1, a base station (BS) 110, a terminal 120, and a terminal 130 are illustrated as the part of nodes using a wireless channel in a wireless communication system. FIGURE 1 illustrates only one BS, but another BS, which is the same as or similar to the BS 110, may be further included.

The BS 110 is network infrastructure that provides wireless access to the

terminals

120 and 130. The BS 110 has coverage defined as a predetermined geographical region based on the distance at which a signal can be transmitted. The BS 110 may be referred to as "access point (AP)," "eNodeB (eNB)," "5th generation (5G) node," "wireless point," "transmission/reception Point (TRP)" as well as "base station."

Each of the

terminals

120 and 130 is a device used by a user, and performs communication with the BS 110 through a wireless channel. Depending on the case, at least one of the

terminals

120 and 130 may operate without user involvement. That is, at least one of the

terminals

120 and 130 is a device that performs machine-type communication (MTC) and may not be carried by the user. Each of the

terminals

120 and 130 may be referred to as "user equipment (UE)," "mobile station," "subscriber station," "remote terminal," "wireless terminal," or "user device" as well as "terminal."

The BS 110, the terminal 120, and the terminal 130 may transmit and receive wireless signals in millimeter wave (mmWave) bands (for example, 28 GHz, 30 GHz, 38 GHz, and 60 GHz). At this time, in order to improve a channel gain, the BS 110, the terminal 120, and the terminal 130 may perform beamforming. The beamforming may include transmission beamforming and reception beamforming. That is, the BS 110, the terminal 120, and the terminal 130 may assign directivity to a transmission signal and a reception signal. To this end, the BS 110 and the

terminals

120 and 130 may select serving

beams

112, 113, 121, and 131 through a beam search procedure or a beam management procedure. After that, communications may be performed using resources having a quasi co-located relationship with resources carrying the serving

beams

112, 113, 121, and 131.

A first antenna port and a second antenna ports are considered to be quasi co-located if the large-scale properties of the channel over which a symbol on the first antenna port is conveyed can be inferred from the channel over which a symbol on the second antenna port is conveyed. The large-scale properties may include one or more of delay spread, doppler spread, doppler shift, average gain, average delay, and spatial Rx parameters.

FIGURE 2 illustrates the BS in the wireless communication system according to various embodiments of the present disclosure. A structure exemplified at FIGURE 2 may be understood as a structure of the BS 110. The term "-module", "-unit" or "-er" used hereinafter may refer to the unit for processing at least one function or operation and may be implemented in hardware, software, or a combination of hardware and software.

Referring to FIGURE 2, the BS may include a wireless communication interface 210, a backhaul communication interface 220, a storage unit 230, and a controller 240.

The wireless communication interface 210 performs functions for transmitting and receiving signals through a wireless channel. For example, the wireless communication interface 210 may perform a function of conversion between a baseband signal and bitstreams according to a physical layer standard of the system. For example, in data transmission, the wireless communication interface 210 generates complex symbols by encoding and modulating transmission bitstreams. Further, in data reception, the wireless communication interface 210 reconstructs reception bitstreams by demodulating and decoding the baseband signal.

In addition, the wireless communication interface 210 up-converts the baseband signal into an Radio Frequency (RF) band signal, transmits the converted signal through an antenna, and then down-converts the RF band signal received through the antenna into the baseband signal. To this end, the wireless communication interface 210 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital-to-analog convertor (DAC), an analog-to-digital convertor (ADC), and the like. Further, the wireless communication interface 210 may include a plurality of transmission/reception paths. In addition, the wireless communication interface 210 may include at least one antenna array consisting of a plurality of antenna elements.

On the hardware side, the wireless communication interface 210 may include a digital unit and an analog unit, and the analog unit may include a plurality of sub-units according to operation power, operation frequency, and the like. The digital unit may be implemented as at least one processor (e.g., a digital signal processor (DSP)).

The wireless communication interface 210 transmits and receives the signal as described above. Accordingly, the wireless communication interface 210 may be referred to as a "transmitter" a "receiver," or a "transceiver." Further, in the following description, transmission and reception performed through the wireless channel may be used to have a meaning including the processing performed by the wireless communication interface 210 as described above.

The backhaul communication interface 220 provides an interface for performing communication with other nodes within the network. That is, the backhaul communication interface 220 converts bitstreams transmitted to another node, for example, another access node, another BS, a higher node, or a core network, from the BS into a physical signal and converts the physical signal received from the other node into the bitstreams.

The storage unit 230 stores a basic program, an application, and data such as setting information for the operation of the BS 110. The storage unit 230 may include a volatile memory, a non-volatile memory, or a combination of volatile memory and non-volatile memory. Further, the storage unit 230 provides stored data in response to a request from the controller 240.

The controller 240 controls the general operation of the BS. For example, the controller 240 transmits and receives a signal through the wireless communication interface 210 or the backhaul communication interface 220. Further, the controller 240 records data in the storage unit 230 and reads the recorded data. The controller 240 may performs functions of a protocol stack that is required from a communication standard. According to another implementation, the protocol stack may be included in the wireless communication interface 210. To this end, the controller 240 may include at least one processor. According to various embodiments, the controller 240 may includes. Here, may be a command/code temporarily resided in the controller 240, a storage space that stores the command/code, or a part of circuitry of the controller 240.

According to exemplary embodiments of the present disclosure, the controller 240 may determine a transmission beam of a terminal based on a preamble sequence received from the terminal. Further, the controller 240 may determine, an identifier for the transmission beam based on a preset mapping relationship. Then, the controller 240 may control to transmit, to the terminal, a random access response comprising the identifier for the transmission beam. For example, the controller 240 may control the base station to perform operations according to the exemplary embodiments of the present disclosure.

FIGURE 3 illustrates the terminal in the wireless communication system according to various embodiments of the present disclosure. A structure exemplified at FIGURE 3 may be understood as a structure of the terminal 120 or the terminal 130. The term "-module", "-unit" or "-er" used hereinafter may refer to the unit for processing at least one function or operation, and may be implemented in hardware, software, or a combination of hardware and software.

Referring to FIGURE 3, the terminal 120 includes a communication interface 310, a storage unit 320, and a controller 330.

The communication interface 310 performs functions for transmitting/receiving a signal through a wireless channel. For example, the communication interface 310 performs a function of conversion between a baseband signal and bitstreams according to the physical layer standard of the system. For example, in data transmission, the communication interface 310 generates complex symbols by encoding and modulating transmission bitstreams. Also, in data reception, the communication interface 310 reconstructs reception bitstreams by demodulating and decoding the baseband signal. In addition, the communication interface 310 up-converts the baseband signal into an RF band signal, transmits the converted signal through an antenna, and then down-converts the RF band signal received through the antenna into the baseband signal. For example, the communication interface 310 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC.

Further, the communication interface 310 may include a plurality of transmission/reception paths. In addition, the communication interface 310 may include at least one antenna array consisting of a plurality of antenna elements. In the hardware side, the wireless communication interface 210 may include a digital circuit and an analog circuit (for example, a radio frequency integrated circuit (RFIC)). The digital circuit and the analog circuit may be implemented as one package. The digital circuit may be implemented as at least one processor (e.g., a DSP). The communication interface 310 may include a plurality of RF chains. The communication interface 310 may perform beamforming.

The communication interface 310 transmits and receives the signal as described above. Accordingly, the communication interface 310 may be referred to as a "transmitter," a "receiver," or a "transceiver." Further, in the following description, transmission and reception performed through the wireless channel is used to have a meaning including the processing performed by the communication interface 310 as described above.

The storage unit 320 stores a basic program, an application, and data such as setting information for the operation of the terminal 120. The storage unit 320 may include a volatile memory, a non-volatile memory, or a combination of volatile memory and non-volatile memory. Further, the storage unit 320 provides stored data in response to a request from the controller 330.

The controller 330 controls the general operation of the terminal 120. For example, the controller 330 transmits and receives a signal through the communication interface 310. Further, the controller 330 records data in the storage unit 320 and reads the recorded data. The controller 330 may performs functions of a protocol stack that is required from a communication standard. According to another implementation, the protocol stack may be included in the communication interface 310. To this end, the controller 330 may include at least one processor or microprocessor, or may play the part of the processor. Further, the part of the communication interface 310 or the controller 330 may be referred to as a communication processor (CP). According to various embodiments, the controller 330 may includes . Here, may be a command/code temporarily resided in the controller 330, a storage space that stores the command/code, or a part of circuitry of the controller 330.

According to exemplary embodiments of the present disclosure, the controller 330 may control to transmit, to a base station, a preamble sequence. Further, the controller 330 may control to receive, from the base station, a random access response comprising a identifier for a transmission beam. For example, the controller 330 may control the terminal to perform operations according to the exemplary embodiments of the present disclosure.

FIGURE 4 illustrates the communication interface in the wireless communication system according to various embodiments of the present disclosure. FIGURE 4 shows an example for the detailed configuration of the communication interface 210 of FIGURE 2 or the communication interface 310 of FIGURE 3. More specifically, FIGURE 4 shows elements for performing beamforming as part of the communication interface 210 of FIGURE 2 or the communication interface 310 of FIGURE 3.

Referring to FIGURE 4, the

communication interface

210 or 310 includes an encoding and circuitry 402, a digital circuitry 404, a plurality of transmission paths 406-1 to 406-N, and an analog circuitry 408.

The encoding and circuitry 402 performs channel encoding. For the channel encoding, at least one of a low-density parity check (LDPC) code, a convolution code, and a polar code may be used. The encoding and circuitry 402 generates modulation symbols by performing constellation mapping.

The digital circuitry 404 performs beamforming for a digital signal (for example, modulation symbols). To this end, the digital circuitry 404 multiples the modulation symbols by beamforming weighted values. The beamforming weighted values may be used for changing the size and phrase of the signal, and may be referred to as a "precoding matrix" or a "precoder." The digital circuitry 404 outputs the digitally beamformed modulation symbols to the plurality of transmission paths 406-1 to 406-N. At this time, according to a multiple input multiple output (MIMO) transmission scheme, the modulation symbols may be multiplexed, or the same modulation symbols may be provided to the plurality of transmission paths 406-1 to 406-N.

The plurality of transmission paths 406-1 to 406-N convert the digitally beamformed digital signals into analog signals. To this end, each of the plurality of transmission paths 406-1 to 406-N may include an inverse fast Fourier transform (IFFT) calculation unit, a cyclic prefix (CP) insertion unit, a DAC, and an up-conversion unit. The CP insertion unit is for an orthogonal frequency division multiplexing (OFDM) scheme, and may be omitted when another physical layer scheme (for example, a filter bank multi-carrier: FBMC) is applied. That is, the plurality of transmission paths 406-1 to 406-N provide independent signal processing processes for a plurality of streams generated through the digital beamforming. However, depending on the implementation, some of the elements of the plurality of transmission paths 406-1 to 406-N may be used in common.

The analog circuitry 408 performs beamforming for analog signals. To this end, the digital circuitry 404 multiples the analog signals by beamforming weighted values. The beamformed weighted values are used for changing the size and phrase of the signal. More specifically, according to a connection structure between the plurality of transmission paths 406-1 to 406-N and antennas, the analog circuitry 408 may be configured in various ways. For example, each of the plurality of transmission paths 406-1 to 406-N may be connected to one antenna array. In another example, the plurality of transmission paths 406-1 to 406-N may be connected to one antenna array. In still another example, the plurality of transmission paths 406-1 to 406-N may be adaptively connected to one antenna array, or may be connected to two or more antenna arrays.

In view of the problems resulted from the indication of an optimal beam in a 5G communication system, the present disclosure proposes a random access method. The random access method has the following principle: the transmitting beamforming direction is implicitly indicated by using a random access-radio network temporary identifier (RA-RNTI), a cell-radio network temporary identifier (C-RNTI) or other parameter identifiers, without increasing the data volume of the random access response.

FIGURE 6 is a flowchart of a random access method according to various embodiments of the present disclosure, comprising the following four steps.

In the first step, a base station transmits system configuration information. The configuration information comprises random access channel configuration information (preamble sequence format, preamble sequence occupation time-frequency resource, etc.) and also a mapping relationship between a transmitting beam direction and the indication identifier. The indication identifier may be an RA-RNTI, a C-RNTI or other parameter identifiers.

In the second step, based on the received random access channel configuration information, the user randomly selects a preamble sequence and transmits the preamble sequence on the corresponding time-frequency resource by conventional single-port beam polling or multi-port beam polling. Upon detecting the preamble sequence, the base station can know an optimal transmitting beam direction and a deviation thereof according to the received energy or signal for each beam.

In the third step, the base station determines, based on the detected optimal user transmitting beam direction and the deviation thereof and also the mapping relationship between the transmitting beam direction and the indication identifier, an indication identifier to which the optimal user transmitting beam direction is mapped, and transmits a Random Access Response (RAR) containing the indication identifier. In this case, the user equipment detects the indication identifier in the random access response based on the time-frequency resource used by its own preamble sequence, and determines a transmitting beamforming direction, i.e., an optimal transmitting beam direction, according to the mapping relationship between the transmitting beam direction and the indication identifier received in the first step.

In the fourth step, the user equipment transmits a signal in the transmitting beamforming direction indicated by the base station, and the signal is then received by the base station. The signal transmitted by the user equipment in the transmitting beamforming direction indicated by the base station may be a Message 3 (Msg3). The Msg3 contains information such as a user equipment identifier and an RRC link request, wherein the user equipment identifier is an identifier that is unique to the user equipment and used for resolving a collision. Thereafter, the base station may transmit a collision resolution identifier to the user, the collision resolution identifier containing an identifier of a user equipment who wins in the collision resolution. The user equipment upgrades TC-RNTI to C-RNTI upon detecting the identifier of the user equipment who wins in the collision resolution, and transmits an Acknowledgement (ACK) signal to the base station to complete the random access process and then waits for the scheduling of the base station. Otherwise, the user equipment will start a new random access process after a certain delay.

It is to be noted that, in the first step, the base station may not transmit the mapping relationship between the transmitting beam direction and the indication identifier. In this case, in the third step, the base station determines an indication identifier based on the detected optimal user transmitting beam direction and the deviation thereof and also based on the random access resource corresponding to this direction, and transmits a Random Access Response (RAR) containing the indication identifier. Subsequently, the user equipment detects the indication identifier in the random access response based on the time-frequency resource used by the user equipment itself for transmitting the preamble sequence by polling, and determines the corresponding preamble sequence time-frequency resource according to the detected indication identifier so as to finally determine the optimal transmitting beam direction. In the second step, the user equipment may transmit the preamble sequence by single-port beam polling or multi-port beam polling. If the conventional single-port beam polling is adopted, the transmitter side successively transmits a single beam by a single port, and the base station determines the optimal user beam direction according to the received energy. For example, a beamforming coefficient may be expressed as follows:

where M is the number of antennas on the transmitter side, d denotes an interval between antennas, λ denotes the wavelength, and θ denotes the direction of transmitting beams on the transmitter side. If the multi-port beam polling is adopted, the transmitter side transmits two or more beams on orthogonal resources by two or more different ports in several preset directions, and the transmitted beams have a certain correlation. In this way, the receiver side can obtain an estimated deviation of beams on the transmitter side by signal comparison. For example, a preferred beamforming coefficient for two-port beam polling may be expressed as follows:

where N is an even number indicating the number of antennas on the transmitter side, d denotes an interval between antennas, λ denotes the wavelength, and θ denotes the direction of transmitting beams on the transmitter side. It can be seen from the beamforming coefficient that,w_sum is a conventional beamforming coefficient in a beam direction of θ, which is the same as the example where a single beam is transmitted by a single port, called a sum beam in the present disclosure; and, in w_dif, elements in the front half part are the same as those in w_sum, and elements in the rear half part are opposite numbers of the corresponding elements in w_sum, so that w_dif can be regarded as a differential beam of the beam w_sum.

By taking the transmitter side equipped with eight antennas as example, FIGURE 7 illustrates a schematic diagram of the received energy of a sum beam and a differential beam according to various embodiments of the present disclosure. As shown, the sum beam and the differential beam are different in energy distribution although identical in direction. Thus, the ratio of the received signals of the two beams can be used as the basis for judging a deviation from a central beam direction.

FIGURE 8 illustrates a schematic diagram of a ratio of received signals of a differential beam and a sum beam according to various embodiments of the present disclosure. As shown in FIGURE 8, within a certain deviation range, the deviation is in one-to-one correspondence to the ratio of the received signals. In the example shown in FIGURE 8, the deviation range is about [-15°,15°]. If the deviation is within this range, a lookup table can be created according to the ratio of the received signals and the corresponding deviation, and then a corresponding deviation is read from the lookup table according to the ratio of the received signals and then fed back to the transmitter side by the receiver side for adjusting a transmitting beam direction.

The flow shown in FIGURE 6 is applicable to a contention-based random access process. For a contention-free random access process, although the preamble sequence transmitted by the UE is allocated by the base station, it is still necessary to indicate an optimal user transmitting beam direction. Therefore, when indicating the optimal user transmitting beam direction, the differential beam manner provided in this solution can still be used.

Embodiment 1:

In this embodiment, a random access method based on an RA-RNTI when the user equipment transmits a preamble sequence by single-antenna-port beam polling will be described.

As shown in FIGURE 9, both a base station and a user equipment are provided with a transmission structure based on an antenna array shown in FIGURE 9. In FIGURE 9, each link processed by a baseband is connected to an antenna array consisting of Nst antenna units through an up-converter and a Digital-to-Analog Converter (DAC). Each antenna in the antenna array is adjustable in phase only. By adjusting the phase, the antenna array can form beams in a proper direction, so as to realize beamforming of the system.

To ensure the beam coverage, several beam directions in different orientations are specified on the user equipment side in advance. FIGURE 10 is a schematic diagram of user-specified beam directions in this embodiment. In FIGURE 10, the user uses four beams to complete the coverage of a space.

In the first step, the base station transmits system configuration information to the user equipment by a downlink control channel, a downlink broadcast channel, a downlink shared channel or a higher-layer signaling configuration. The system configuration information comprises random access channel configuration information and also a mapping relationship between the RA-RNTI, and the transmitting beam direction and the random access channel resource. Wherein, the mapping relationship may be further expressed as follows: the transmitting beam direction, time resource occupied by random access channel and frequency resource occupied by random access channel are in one-to-one correspondence to the RA-RNTI.

FIGURE 11 is an exemplary view showing a mapping relationship between the RA-RNTI, and the transmitting beam direction and the random access channel resource (PRACH resource). Wherein, the total number of time-frequency resources available for the random access channel is M (the resource index range: 0≤m≤M), the total number of transmitting beam directions is B (the beam index range: 0≤b<B), the total number of RA-RNTIs is N (the identifier index range: 1≤n≤N)), and N≥MB. In such a mapping relationship, one transmitting beam direction corresponds to one or more RA-RNTIs, and those RA-RNTIs correspond to different random access channel resources, respectively. This mapping relationship may be expressed as follows: RA-RNTI=f(b_id,t_id,f_id) ,

where, b_id denotes the index of a user transmitting beam direction (0≤b_id<B), t_id denotes the index of a time resources occupied by random access channel (0≤t_id<T), and f_id denotes the index of a frequency resources occupied by random access channel (0≤f_id<F); and the function g may be specifically expressed as follow:

RA-RNTI=1+b_id+Bt_id+BTf_id

or

RA-RNTI=1+b_id+Bf_id+BFt_id

or

RA-RNTI=1+t_id+Tf_id+TFb_id

or

RA-RNTI=1+t_id+Tb_id+TBf_id

or

RA-RNTI=1+f_id+Ft_id+FTb_id

or

RA-RNTI=1+f_id+Fb_id+FBt_id

In the second step, the user equipment randomly selects a random access preamble sequence based on the received random access channel configuration information, and transmits the preamble sequence successively by corresponding time-frequency resources by single-port beam polling.

FIGURE 12 shows a frame structure when the single-port beam polling solution is adopted in this step, wherein the user has four beam directions, and the user equipment will successively transmit the preamble sequence by single-antenna-port polling in the beam direction 0, the beam direction 1, the beam direction 2 and the beam direction 3, and the duration of transmission in each direction is μ1.

The base station performs preamble sequence detection by means of correlation detection. When the sequence used for the correlation detection is matched with the preamble sequence transmitted by the user equipment, the base station will calculate the energy of the whole preamble sequence. The base station performs correlation detection on the received preamble sequence, and outputs a result of correlation detection performed on the preamble sequence in each beam direction, respectively. Subsequently, the base station obtains an optimal transmitting beam direction, i.e., a transmitting beam direction with the maximum energy, based on the result of correlation detection.

In the third step, based on the time resource index and frequency resource index for the random access channel corresponding to the transmitting beam direction detected in the second step, and also based on the user transmitting beam index, the base station determines a corresponding RA-RNTI according to the mapping relationship between the RA-RNTIs and the beamforming directions and random access channel resources as defined in the first step. Then, the base station scrambles a downlink control channel by using the determined RA-RNTI, and transmits a random access response by a downlink shared channel corresponding to the downlink control channel.

The user equipment detects all possible RA-RNTIs, based on the random access channel resources and also based on the mapping relationship between the RA-RNTIs and the transmitting beam directions and random access channel resources as received in the first step. Based on the detected RA-RNTI, the user can descramble the downlink control channel and can further detect a random access response in the downlink shared channel. Meanwhile, based on the mapping relationship, the user can determine a beamforming direction mapped to this RA-RNTI, i.e., a transmitting beam direction with the maximum energy. In the subsequent random access steps, the user equipment will transmit signals in this transmitting beam direction to complete the random access process.

Of course, in some other embodiments, the system configuration information transmitted by the base station may comprise random access channel configuration information only, without a mapping relationship between the RA-RNTI, and the transmitting beam direction and the random access channel resource. This mapping relationship may be stored in the base station and the user equipment in advance. In the third step, the user equipment calls the stored mapping relationship to determine a beamforming direction mapped to the RA-RNTI.

Embodiment 2:

In this embodiment, a beam random access method based on an RA-RNTI when the user equipment transmits a preamble sequence by multi-antenna-port beam polling will be described. The system configuration is similar to that in Embodiment 1. Both a base station and a user equipment are provided with a transmission structure based on an antenna array shown in FIGURE 9. The user equipment transmits a preamble sequence by multi-port differential beam polling.

To ensure the beam coverage, several spatial directions in different orientations are specified on the user side in advance, and one beam pair is used for the coverage of each direction, respectively. FIGURE 13 is a schematic diagram of user-specified beam pair directions in this embodiment. In FIGURE 13, the user uses four beam pairs to complete the coverage of a space. There is one beam pair in each beam direction.

In the first step, the base station transmits system configuration information to the user equipment by a downlink control channel, a downlink broadcast channel, a downlink shared channel or a higher-layer signaling configuration. The system configuration information comprises random access configuration information and also a mapping relationship between the RA-RNTI, and the transmitting beam direction, the deviation of the transmitting beam direction and the random access channel resource. Wherein, the mapping relation may be further expressed as follows: the transmitting beam direction, the deviation of the transmitting beam direction and the random access channel resource are in one-to-one correspondence to the RA-RNTI.

FIGURE 14 is an exemplary view showing a mapping relationship between the RA-RNTI, and the transmitting beam direction, the deviation of the transmitting beam direction and the random access channel time-frequency resource. Wherein, the total number of time-frequency resources available for the random access channel is M (the resource index range: 0≤m≤M), the total number of transmitting beam directions is B (the beam index range: 0≤b<B), the total number of deviations of the transmitting beam directions is D (the deviation index range: 0≤d<D), the total number of RA-RNTIs is N (the identifier index range: 1≤n≤N), and N≥MBD. In such a mapping relationship, one transmitting beam direction and a deviation of the transmitting beam direction correspond to one or more RA-RNTIs, and those RA-RNTIs correspond to different random access channel resources, respectively. This mapping relationship may be expressed as follows:

RA-RNTI=g(d_id,b_id,r_id)

where, d_id denotes the index of a deviation of a transmitting beam direction (0≤d_id<D), b_id denotes the index of a transmitting beam direction (0≤b_id<B), and m_id denotes the index of a time-frequency resources occupied by random access channel (0≤m_id<M); and the function g may be specifically expressed as follow:

RA-RNTI=1+d_id+Db_id+DBm_id

or

RA-RNTI=1+d_id+Dm_id+DMb_id

or

RA-RNTI=1+b_id+Bd_id+BDm_id

or

RA-RNTI=1+b_id+Bm_id+BMd_id

or

RA-RNTI=1+m_id+Md_id+MDb_id

or

RA-RNTI=1+m_id+Mb_id+MBd_id;

In the second step, the user equipment randomly selects a random access preamble sequence based on the received random access configuration information, and transmits the preamble sequence successively by corresponding time-frequency resources by multi-port differential beam polling.

FIGURE 15 shows a frame structure when the multi-port beam polling solution is adopted in this step, wherein the user has four beam pair directions, and the user equipment will successively transmit the preamble sequence by multi-antenna-port polling in the beam pair direction 0, the beam pair direction 1, the beam pair direction 2 and the beam pair direction 3, and the duration of transmission in each direction is μ2.

There are following specific ways for the user equipment to transmit the preamble sequence:

1. The preamble sequence is divided into two parts. The first part is transmitted by a sum beam, and the second part is transmitted by a differential beam.

2. Identical preamble sequences are transmitted by different resources. For example, identical preamble sequences are transmitted by two sections of successive time resources. Wherein, the first section of resources performs transmission by a sum beam, while the second section of resources performs transmission by a differential beam.

3. Identical or different preamble sequences are transmitted by different antenna arrays. Wherein, some of the antenna arrays transmit the preamble sequence by a sum beam, while the other antenna arrays transmit the preamble sequence by a differential beam. When preamble sequences are transmitted by different antenna arrays, a sum beam sequence and a differential beam sequence can be transmitted respectively by identical frequency resources by using orthogonal codewords, or the sum beam sequence or the differential beam sequence can be transmitted respectively by different frequency resources by using orthogonal codewords or non-orthogonal codewords.

FIGURE 16 is a flowchart of detecting a preamble sequence and a deviation of a transmitting beam direction by a base station. The base station performs correlation detection on the received signal, and outputs results of all signal sequences, respectively, to obtain a result of correlation detection performed on the sum beam sequence and a result of correlation detection performed on the differential beam sequence. Since the sum beam and the differential beam are different in beam characteristics although identical in beam direction, the results of detection cannot be decided by a single threshold. A preferred way of making a decision is as follows: if it is assumed that the result of correlation detection performed on the sum beam sequence part and a certain preamble sequence is

and the result of correlation detection performed on the differential beam sequence part and the same preamble sequence is

, it is considered that this preamble sequence is detected when one of the following conditions is fulfilled: a.

. Wherein,

and

are a first detection threshold and a second detection threshold, respectively, and fulfill the condition of

≤

. The first detection threshold

and the second detection threshold

are determined by factors such as the cell radius, the number of antennas used for beamforming by the user equipment during transmission of the preamble sequence, and the length of the preamble sequence.

If a certain preamble sequence is detected, a signal ratio is calculated according to the result of correlation detection performed on the sum beam sequence and the result of correlation detection performed on the differential beam sequence corresponding to the preamble sequence, and the deviation of the user transmitting beam direction is obtained based on the principle of the differential beam solution. The base station quantifies possible deviations and then creates a corresponding lookup table. Upon detecting the deviation of the transmitting beam, the base station quantifies this deviation and then searches for a corresponding index from the lookup table. Specifically, if the user transmits identical preamble sequences by using beams in different directions, the base station estimates the received energy to obtain a time slot with the highest received energy, then estimates a deviation of a user transmitting beam direction within this time slot, and finally obtains a transmitting beam direction with the maximum energy and a deviation of the transmitting beam.

In the third step, based on the time-frequency resource index for the random access channel corresponding to the transmitting beam direction detected in the second step, and also based on the transmitting beam direction index and the deviation of the transmitting beam direction, the base station determines a corresponding RA-RNTI according to the mapping relationship between the RA-RNTI and the transmitting beam direction, deviation of the transmitting beam direction and random access channel resource as defined in the first step. Then, the base station scrambles a downlink control channel by using the RA-RNTI, and transmits a random access response by a downlink shared channel corresponding to the downlink control channel.

The user equipment detects all possible RA-RNTIs, based on the random access channel resources and also based on the mapping relationship between the RA-RNTIs and the beamforming direction, deviation of the direction and random access channel resources as received in the first step. The user can descramble the downlink control channel by using the detected RA-RNTI and can further detect the random access response in the downlink shared channel. Meanwhile, in accordance with the mapping relationship, a transmitting beamforming direction, i.e., a transmitting beam direction with the maximum energy, can be determined. In the subsequent random access steps, the user equipment transmits a signal in this beam direction.

It is to be noted that, in the solution of this embodiment, the user equipment is indicated with both the transmitting beam direction and the deviation of the transmitting beam direction in a display manner based on the RA-RNTI. And this indication method is also applicable to a case where only the deviation of the transmitting beam direction is indicated.

In this case, the base station needs to establish a mapping relationship from the deviation of the transmitting beam direction and time-frequency resources occupied by random access channel to the RA-RNTI in the first step, and transmit the mapping relationship to the user equipment, and use this mapping relationship in the subsequent steps. Finally, the user equipment determines the deviation of the transmitting beam direction based on the detected RA-RNTI.

Of course, in some other embodiments, the system configuration information transmitted by the base station may comprise random access configuration information only, without a mapping relationship between the RA-RNTI, and the transmitting beam direction, the deviation of the transmitting beam direction and the random access channel resource. This mapping relationship may be stored in the base station and the user equipment in advance. In the third step, the user equipment may call the stored mapping relationship to determine a beamforming direction mapped to the RA-RNTI.

Embodiment 3:

In this embodiment, a beam random access method based on a temporary C-RNTI when the user equipment transmits a preamble sequence by single-antenna-port or multi-antenna-port beam polling will be described. Both a base station and a user equipment are provided with a transmission structure based on an antenna array shown in FIGURE 9. To ensure the beam coverage, several beam directions in different orientations are specified on the user side in advance.

In the first step, the base station transmits system configuration information to the user equipment by a downlink control channel, a downlink broadcast channel, a downlink shared channel or a higher-layer signaling configuration. The system configuration information comprises random access configuration information and also a mapping relationship from the transmitting beam direction and the deviation of the transmitting beam direction to the C-RNTI. This mapping relation may be further expressed as follows: a transmitting beam direction and a deviation of the transmitting beam direction correspond to one or more non-overlapped C-RNTIs.

FIGURE 17 is an exemplary view showing a mapping relationship from the transmitting beam direction and the deviation of the transmitting beam direction to the C-RNTI. Wherein, the total number of transmitting beam directions and deviations of the transmitting beam directions is B (the index range: 0≤b<B), the total number of C-RNTIs is C (the identifier index range: 1≤c≤C), and the beam index b corresponds to G_b C-RNTIs.

For example, if the user equipment uses four beams or beam pairs in different directions to transmit a preamble sequence, a set Φ of C-RNTIs is divided into four disjoint subsets Φ₁, Φ₂, Φ₃, Φ₄. The four subsets fulfill the following conditions:

Φ₁∩Φ₂∩Φ₃∩Φ₄=

Φ₁∪Φ₂∪Φ₃∪Φ₄=Φ

wherein, each subset of C-RNTIs corresponds to one transmitting beam direction and a deviation of the transmitting beam direction.

In the second step, the user equipment randomly selects a random access preamble sequence based on the received random access configuration information, and transmits the preamble sequence successively by corresponding time-frequency resources by single-port beam polling or multi-port differential beam polling.

The base station performs preamble sequence detection by means of correlation detection. When the sequence used for the correlation detection is matched with the received preamble sequence, the result of detection is equivalent to the calculation of the energy of the whole preamble sequence. If the user transmits the preamble sequence successively by single-port beam polling, the base station performs correlation detection on the received signal, outputs a result of correlation detection in each transmitting beam direction, respectively, and obtains an optimal user transmitting beam direction according to the largest value among the results of correlation detection. If the user transmits the preamble sequence successively by multi-port beam polling, the detection is performed according to the flow as shown in FIGURE 12. That is, the preamble sequence is detected first, a transmitting beam direction is then determined, and a deviation of the transmitting beam direction is detected. If the result of correlation detection indicates that no preamble sequence is detected, the subsequent steps will not be executed; and, if the correlation detection module has detected preamble sequences, beam direction deviation detection is performed on each of the detected preamble sequences, that is, a deviation between a receiving direction and an array beam direction is obtained according to the result of correlation detection from the sum beam array and the result of correlation detection from the differential beam array.

In the third step, based on the transmitting beam direction and the deviation of the transmitting beam direction as detected in the second step, the base station randomly selects, according to the mapping relationship form the transmitting beam direction and the deviation of the transmitting beam direction to the C-RNTI, an unused C-RNTI from a corresponding subset of C-RNTIs as a temporary C-RNTI which is to be transmitted in the random access response.

The user equipment detects the temporary C-RNTI in the random access response, and based on the mapping relationship from the transmitting beam direction and the deviation of the transmitting beam direction to the C-RNTI in the first step, determines a transmitting beamforming direction and an angular deviation thereof. In the subsequent random access steps, the user equipment transmits a signal in this transmitting beam direction.

Of course, in some other embodiments, the system configuration information transmitted by the base station may comprise random access configuration information only, without a mapping relationship from the transmitting beam direction and the deviation of the transmitting beam direction to the C-RNTI. This mapping relationship may be stored in the base station and the user equipment in advance. In the third step, the user equipment may call the stored mapping relationship to determine a beamforming direction mapped to this C-RNTI.

Embodiment 4:

In this embodiment, a beam random access method based on an RA-RNTI when the user equipment transmits a preamble sequence by single-antenna-port or multi-antenna-port beam polling will be described. Both a base station and a user equipment are provided with a transmission structure based on an antenna array shown in FIGURE 9. To ensure the beam coverage, several beam directions in different orientations are specified on the user side in advance.

In the first step, the base station transmits system configuration information to the user equipment by a downlink control channel, a downlink broadcast channel, a downlink shared channel or a higher-layer signaling configuration. The system configuration information comprises random access configuration information such as preamble sequence format and random access resource configuration.

FIGURE 18 shows a frame structure when the beam polling solution is adopted in this step, wherein the user has four beam directions, and the user equipment will successively transmit the preamble sequence by beam polling by using different random access channel resources in the beam direction 0, the beam direction 1, the beam direction 2 and the beam direction 3, and the duration of transmission in each direction is μ3.

The base station performs preamble sequence detection by means of correlation detection. When the sequence used for the correlation detection is matched with the received preamble sequence, the result of detection is equivalent to the calculation of the energy of the whole preamble sequence. If the user transmits the preamble sequence successively by single-port beam polling, the base station performs correlation detection on the received signal, outputs a result of correlation detection in each transmitting beam direction, respectively, and obtains an optimal user transmitting beam direction according to the largest value among the results of correlation detection. If the user transmits the preamble sequence successively by multi-port beam polling, the detection is performed according to the flow as shown in FIGURE 16. That is, the preamble sequence is detected first, a transmitting beam direction is then determined, and a deviation of the transmitting beam direction is detected. If the result of correlation detection indicates that no preamble sequence is detected, the subsequent steps will not be executed; and, if the correlation detection module has detected preamble sequences, beam direction deviation detection is performed on each of the detected preamble sequences, that is, a deviation between a receiving direction and an array beam direction is obtained according to the result of correlation detection from the sum beam array and the result of correlation detection from the differential beam array.

In the third step, based on the time resource index and frequency resource index for the random access channel corresponding to the transmitting beam direction detected in the second step, the base station determines an RA-RNTI according to the preset mapping relationship between the RA-RNTI and the random access channel resource. Wherein, the mapping relationship may be further expressed as follows: the time resource occupied by random access channel and the frequency resource occupied by random access channel are in one-to-one correspondence to the RA-RNTI.

FIGURE 19 is an exemplary view showing a mapping relationship between the RA-RNTI and the random access channel resource (PRACH resource). Wherein, the total number of time-frequency resources available for the random access channel is M (the resource index range: 0≤m≤M), the total number of RA-RNTIs is N (the identifier index range: 1≤n≤N), and N≥MB. This mapping relationship may be expressed as follows:

RA-RNTI=f(t_id,f_id)

where, t_id denotes the index of the time resources occupied by random access channel (0≤t_id<T), and f_id denotes the index of the frequency resources occupied by random access channel (0≤f_id<F); and the function f may be specifically expressed as follow:

RA-RNTI=1+t_id+Tf_id

or

RA-RNTI=1+f_id+Ft_id

Then, the base station scrambles a downlink control channel by using the determined RA-RNTI, and transmits a random access response by a downlink shared channel corresponding to the downlink control channel.

The user equipment detects all possible RA-RNTIs, based on the random access channel resources used in the beam polling in the step 2 and also based on the mapping relationship between the RA-RNTI and the random access channel resource. The user can descramble the downlink control channel by using the detected RA-RNTI and can further detect the random access response in the downlink shared channel. Meanwhile, based on the detected RA-RNTI, the user equipment can determine a random access channel resource mapped to this RA-RNTI, and determine a corresponding beamforming direction for transmitting the preamble sequence by using this resource, i.e., a transmitting beam direction with the maximum energy. In the subsequent random access steps, the user equipment will transmit signals in this transmitting beam direction to complete the random access process.

Embodiment 5:

Thereinafter, a random access method according to this embodiment of the present disclosure will be described from the base station side only. As shown in FIGURE 20, the random access method comprises the following steps of:

S101: receiving, by a base station, a preamble sequence transmitted by a user equipment;

S102: determining a transmitting beam direction with the maximum energy based on the preamble sequence;

S103: determining, in accordance with a preset mapping relationship, an indication identifier to which the transmitting beam direction with the maximum energy is mapped;

S104: transmitting a random access response containing the indication identifier to the user equipment; and

S105: receiving a signal transmitted by the user equipment in the transmitting beam direction with the maximum energy.

During the application of the method of this embodiment, an agreement on an identical mapping relationship between a transmitting beam direction and an indication identifier is reached between the base station and the user equipment. This mapping relationship is stored in the memories of the base station and the user equipment in advance. Before the step S101, the base station transmits system configuration information to the user equipment by a downlink control channel, a downlink broadcast channel, a downlink shared channel or a higher-layer signaling configuration. The system configuration information comprises random access configuration information. The preamble sequence received in the step S101 is randomly selected by the user equipment based on the received random access configuration information.

In the step 102, the base station performs preamble sequence detection by means of correlation detection. When the sequence used for the correlation detection is matched with the preamble sequence transmitted by the user equipment, the base station will calculate the energy of the whole preamble sequence. The base station performs correlation detection on the received preamble sequence, and outputs a result of correlation detection performed on the preamble sequence in each beam direction, respectively. Subsequently, the base station obtains an optimal transmitting beam direction, i.e., a transmitting beam direction with the maximum energy, based on the result of correlation detection.

Wherein, the preamble sequence received by the base station is transmitted by the user equipment by single-port beam polling or multi-port beam polling, and the indication identifier may be a C-RNTI, an RA-RNTI or other parameter identifiers.

In one implementation, when the preamble sequence received by the base station is transmitted by the user equipment by single-port beam polling, and the indication identifier is an RA-RNTI, this mapping relationship is specifically a mapping relationship from the transmitting beam direction and the time resource occupied by random access channel and frequency resource occupied by random access channel to the RA-RNTI. The step S103 is specifically as follows: the base station determines an RA-RNTI to which the transmitting beam direction with the maximum energy and the time resource occupied by random access channel and frequency resource occupied by random access channel, scrambles the downlink control channel by using the determined RA-RNTI, and transmits a random access response in a downlink shared channel corresponding to the downlink control channel.

In one implementation, when the preamble sequence received by the base station is transmitted by the user equipment by multi-port beam polling, and the indication identifier is an RA-RNTI, this mapping relationship is a mapping relationship from the transmitting beam direction, the deviation of the transmitting beam direction and the random access channel resource to the RA-RNTI.

The step S102 may specifically refer to the flowchart of detecting a preamble sequence and a deviation of a transmitting beam direction by a base station in FIGURE 16. The base station performs correlation detection on the received signal, and outputs results of all signal sequences, respectively, to obtain a result of correlation detection performed on the sum beam sequence and a result of correlation detection performed on the differential beam sequence. Since the sum beam and the differential beam are different in beam characteristics although identical in beam direction, the results of detection cannot be decided by a single threshold. A preferred way of making a decision is as follows: if it is assumed that the result of correlation detection performed on the sum beam sequence part and a certain preamble sequence is

Wherein,

and

≤

. The first detection threshold

and the second detection threshold

The step S103 is specifically as follows: the base station determines an RA-RNTI to which the transmitting beam direction with the maximum energy, the deviation of the transmitting beam direction and the random access channel resource are mapped, scrambles the downlink control channel by using the determined RA-RNTI, and transmits a random access response in a downlink shared channel corresponding to the downlink control channel.

In one implementation, when the preamble sequence received by the base station is transmitted by the user equipment by single-port beam polling or multi-port beam polling, and the indication identifier is a C-RNTI, this mapping relationship is a mapping relationship from the transmitting beam direction and the deviation of the transmitting beam direction to the C-RNTI.

The step S102 is specifically as follows: the base station performs preamble sequence detection by means of correlation detection. When the sequence used for the correlation detection is matched with the received preamble sequence, the result of detection is equivalent to the calculation of the energy of the whole preamble sequence. If the user transmits the preamble sequence successively by single-port beam polling, the base station performs correlation detection on the received signal, outputs a result of correlation detection in each transmitting beam direction, respectively, and obtains an optimal user transmitting beam direction according to the largest value among the results of correlation detection. If the user equipment transmits the preamble sequence by multi-port beam polling, the detection is performed according to the flow as shown in FIGURE 16. That is, the preamble sequence is detected first, a transmitting beam direction is then determined, and a deviation of the transmitting beam direction is detected. If the result of correlation detection indicates that no preamble sequence is detected, the subsequent steps will not be executed; and, if the correlation detection module has detected preamble sequences, beam direction deviation detection is performed on each of the detected preamble sequences, that is, a deviation between a receiving direction and an array beam direction is obtained according to the result of correlation detection from the sum beam array and the result of correlation detection from the differential beam array.

After the transmitting beam direction with the maximum energy and the deviation of the transmitting beam direction are determined, a C-RNTI to which the transmitting beam direction with the maximum energy and the deviation of the transmitting beam direction are mapped is determined, an unused C-RNTI is randomly selected from a corresponding subset of C-RNTIs as a temporary C-RNTI which is to be transmitted in the random access response.

Embodiment 6:

In this embodiment, corresponding to Embodiment 5, a random access method of this embodiment of the present disclosure will be described from the user equipment side. As shown in FIGURE 21, the random access method comprises the following steps of:

S201: transmitting, by a user equipment, a preamble sequence to the base station;

S202: receiving a random access response containing an indication identifier, which is transmitted by the base station;

S203: determining, in accordance with a preset mapping relationship, a transmitting beam direction with the maximum energy mapped to the indication identifier; and

S204: transmitting a signal to the base station in the transmitting beam direction with the maximum energy.

During the application of the method of this embodiment, an agreement on an identical mapping relationship between a transmitting beam direction and an indication identifier is reached between the base station and the user equipment. This mapping relationship is stored in the memories of the base station and the user equipment in advance.

Before the step S201, the user equipment further receives the system configuration information transmitted by the base station by a downlink control channel, a downlink broadcast channel, a downlink shared channel or a higher-layer signaling configuration. The system configuration information comprises random access configuration information. In accordance with the random access configuration information, the user equipment randomly selects a random access preamble sequence and transmits the random access preamble sequence to the base station.

In the step 203, the user equipment determines the indication identifier in the random access response, and in accordance with the preset mapping relationship, determines a transmitting beam direction with the maximum energy mapped to the indication identifier, and thus transmits a signal in the transmitting beam direction with the maximum energy in the step S204 to complete the random access process.

Wherein, the user equipment transmits the preamble sequence by single-port beam polling or multi-port beam polling, and the indication identifier may be a C-RNTI, a RA-RNTI or other parameter identifiers.

In one implementation, when the user equipment transmits the preamble sequence by single-port beam polling, and the indication identifier is a RA-RNTI, this mapping relationship is specifically a mapping relationship from the transmitting beam direction, time resources occupied by random access channel and frequency resources occupied by random access channel to the RA-RNTI.

The step S202 is specifically as follows: the user equipment detects all possible RA-RNTIs, based on the random access channel resources and also based on the preset mapping relationship between the RA-RNTI, and the transmitting beam direction and the random access channel resource. The user can descramble the downlink control channel by using the detected RA-RNTI and can further detect the random access response in the downlink shared channel.

In the step S203, the user equipment determines a transmitting beam direction with the maximum energy mapped to the indication identifier, based on the random access channel resources and also based on the preset mapping relationship between the RA-RNTI, and the transmitting beam direction and the random access channel resource, and thus transmits a signal in the transmitting beam direction with the maximum energy in the step S204.

In one implementation, when the user equipment transmits the preamble sequence by multi-port beam polling, and the indication identifier is a RA-RNTI, this mapping relationship is a mapping relationship from the transmitting beam direction, the deviation of the transmitting beam direction and the random access channel resource to the RA-RNTI.

The step S202 is specifically as follows: the user equipment detects all possible RA-RNTIs, based on the random access channel resources and also based on the preset mapping relationship from the transmitting beam direction, the deviation of the transmitting beam direction and the random access channel resource to the RA-RNTI. The user equipment can descramble the downlink control channel by using the detected RA-RNTI and can further detect the random access response in the downlink shared channel.

In the step S203, the user equipment determines a transmitting beam direction with the maximum energy mapped to the indication identifier, based on the random access channel resources and also based on the mapping relationship between the RA-RNTI, and the transmitting beam direction and the random access channel resource as received in the first step, and thus transmits a signal in the transmitting beam direction with the maximum energy in the step S204.

In one implementation, when the preamble sequence is transmitted by the user equipment by single-port beam polling or multi-port beam polling, and the indication identifier is a C-RNTI, this mapping relationship is a mapping relationship from the transmitting beam direction and the deviation of the transmitting beam direction to the C-RNTI.

In the step S201, there are following specific ways for the user equipment to use four beams or beam pairs to transmit a preamble sequence by multi-port transmission:

In the step S203, the user equipment detects the temporary C-RNTI in the random access response, and based on the mapping relationship from the transmitting beam direction and the deviation of the transmitting beam direction to the C-RNTI, determines a transmitting beamforming direction and an angular deviation thereof. In the step S204 and in the subsequent random access steps, the user equipment transmits a signal in this transmitting beam direction.

Embodiment 7:

In this embodiment, a random access method according to this embodiment of the present disclosure will be described from the base station side only. As shown in FIGURE 22, the random access method comprises the following steps of:

S301: transmitting, by a base station, system configuration information to the user equipment, the configuration information comprising random access channel configuration information and also a mapping relationship between a transmitting beam direction and the indication identifier;

S302: receiving the preamble sequence transmitted by the user equipment based on the random access channel configuration information;

S303: determining a transmitting beam direction with the maximum energy based on the preamble sequence;

S304: determining, in accordance with the mapping relationship, an indication identifier to which the transmitting beam direction with the maximum energy is mapped;

S305: transmitting a random access response containing the indication identifier to the user equipment; and

S306: receiving a signal transmitted by the user equipment in the transmitting beam direction with the maximum energy.

Compared with Embodiment 5, in this embodiment, no agreement on the mapping relationship between a transmitting beam direction and an indication identifier is reached between the user equipment and the base station. A mapping relationship between a transmitting beam direction and an indication identifier is established by the base station in advance and then contained in the system configuration information which is transmitted to the user equipment in the step S301. The user equipment determines a transmitting beam direction with the maximum energy mapped to the indication identifier, based on the mapping relationship transmitted in the step S301.

Wherein, the preamble sequence received by the base station is transmitted by the user equipment by single-port beam polling or multi-port beam polling, and the indication identifier may be a C-RNTI, a RA-RNTI or other parameter identifiers.

Embodiment 8:

In this embodiment, corresponding to Embodiment 7, a random access method of this embodiment of the present disclosure will be described from the user equipment side only. As shown in FIGURE 23, the random access method comprises the following steps of:

S401: receiving, by a user equipment, system configuration information transmitted by the base station, the configuration information comprising random access channel configuration information and also a mapping relationship between a transmitting beam direction and the indication identifier;

S402: transmitting a preamble sequence to the base station based on the random access channel configuration information;

S403: receiving a random access response containing an indication identifier, which is transmitted by the base station;

S404: determining, in accordance with the mapping relationship, a transmitting beam direction with the maximum energy mapped to the indication identifier; and

S405: transmitting a signal to the base station in the transmitting beam direction with the maximum energy.

Compared with Embodiment 6, in this embodiment, no agreement on the mapping relationship between a transmitting beam direction and an indication identifier is reached between the user equipment and the base station. In the step S401, upon receiving the system configuration information, the user equipment extracts the mapping relationship between a transmitting beam direction and an indication identifier from the system configuration information. And, in the step S404, a transmitting beam direction with the maximum energy mapped to the indication identifier is determined in accordance with the mapping relationship.

Wherein, the preamble sequence is transmitted by the user equipment by single-port beam polling or multi-port beam polling, and the indication identifier may be a C-RNTI, a RA-RNTI or other parameter identifiers.

Embodiment 9:

This embodiment provides a base station, as shown in FIGURE 24, comprising: a first receiving module 501 configured to receive a preamble sequence transmitted by a user equipment; a first determination module 502 configured to determine a transmitting beam direction with the maximum energy based on the preamble sequence; a second determination module 503 configured to determine, in accordance with a preset mapping relationship, an indication identifier to which the transmitting beam direction with the maximum energy is mapped; a first transmitting module 504 configured to transmit a random access response containing the indication identifier to the user equipment; and a second receiving module 505 configured to receive a signal transmitted by the user equipment in the transmitting beam direction with the maximum energy.

Embodiment 10:

This embodiment provides a user equipment, as shown in FIGURE 25, comprising: a third transmitting module 601 configured to transmit a preamble sequence to a base station; a third receiving module 602 configured to receive a random access response containing an indication identifier, which is transmitted by the base station; a third determination module 603 configured to determine, in accordance with a preset mapping relationship, a transmitting beam direction with the maximum energy mapped to the indication identifier; and a fourth transmitting module 604 configured to transmit a signal to the base station in the transmitting beam direction with the maximum energy.

It may be clearly understood by those skilled in the art that, for the convenience and simplicity of description, the specific operating processes of the described systems, devices and units may refer to the corresponding processes in the embodiments of the method, and will not be repeated herein.

In the embodiments provided in the application, it should be understood that the disclosed system, device and method may be implemented in other ways. For example, the device embodiments described above are merely exemplary. For example, the division of the units is merely division of logical functions. There may be other division ways when in practical implementation, for example, many units or components may be combined together or may be integrated into another system, or some features may be omitted or not executed. In addition, the coupling or direct coupling or communicative connection as shown or discussed may be achieved by some interfaces, and the indirect coupling or communicative connection between the devices or units may be in electric, mechanical or other forms.

The units described as separated components may or may not be separated physically. Components, shown as units, may or may not be physical units, that is, they may be located in one place or distributed over a plurality of network units. Some or all of the units may be selected to implement the purpose of the solutions of the embodiment, as desired.

In addition, the functional units in the embodiments of the present disclosure may be integrated in one processing unit; or the functional units may be physically present as individual units; or two or more of the functional units may be integrated in one unit. The integrated units may be implemented in a form of hardware, or in a form of software functional units.

It may be understood by a person of ordinary skill in the art that all or part of the steps in the methods according to the embodiments may be implemented by instructing related hardware by programs. The programs may be stored in a computer-readable storage medium. The computer-readable storage medium may include Read Only Memories (ROMs), Random Access Memories (RAMs), magnetic disks, optical disks, etc.

The mobile terminal of the present disclosure has been described above in detail. For a person of ordinary skill in the art, various changes may be made to the specific implementations and application ranges without departing from the concept of the embodiments of the present disclosure. Therefore, the content of the description shall not be considered as any limitation to the present disclosure.

Methods according to embodiments stated in claims and/or specifications of the present disclosure may be implemented in hardware, software, or a combination of hardware and software.

When the methods are implemented by software, a computer-readable storage medium for storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium may be configured for execution by one or more processors within the electronic device. The at least one program may include instructions that cause the electronic device to perform the methods according to various embodiments of the present disclosure as defined by the appended claims and/or disclosed herein.

The programs (software modules or software) may be stored in non-volatile memories including a random access memory and a flash memory, a read only memory (ROM), an electrically erasable programmable read only memory (EEPROM), a magnetic disc storage device, a compact disc-ROM (CD-ROM), digital versatile discs (DVDs), or other type optical storage devices, or a magnetic cassette. Alternatively, any combination of some or all of the may form a memory in which the program is stored. Further, a plurality of such memories may be included in the electronic device.

In addition, the programs may be stored in an attachable storage device which is accessible through communication networks such as the Internet, Intranet, local area network (LAN), wide area network (WAN), and storage area network (SAN), or a combination thereof. Such a storage device may access the electronic device via an external port. Further, a separate storage device on the communication network may access a portable electronic device.

In the above-described detailed embodiments of the present disclosure, a component included in the present disclosure is expressed in the singular or the plural according to a presented detailed embodiment. However, the singular form or plural form is selected for convenience of description suitable for the presented situation, and various embodiments of the present disclosure are not limited to a single element or multiple elements thereof. Further, either multiple elements expressed in the description may be configured into a single element or a single element in the description may be configured into multiple elements.

While the present disclosure has been shown and described with reference to certain embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be defined as being limited to the embodiments, but should be defined by the appended claims and equivalents thereof.

Although the present disclosure has been described with an exemplary embodiment, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims.

Claims

A method for operating a base station (BS) in a wireless communication system, the base station comprising:

determining a transmission beam of a terminal based on a preamble sequence received from the terminal;

determining, an identifier for the transmission beam based on a preset mapping relationship; and

transmitting, to the terminal, a random access response comprising the identifier for the transmission beam.
The method of claim 1, wherein the identifier is a random access-radio network temporary identifier (RA-RNTI), and

wherein transmitting, to the terminal, a random access response comprising the identifier for the transmission beam comprises:

scrambling a downlink control channel by using the RA-RNTI; and

transmitting a random access response to the terminal by a downlink shared channel corresponding to the downlink control channel.
The method of claim 2, further comprising:

receiving, from the terminal, the preamble sequence; and

receiving, from the terminal, the preamble sequence based on a single antenna port or multiple antenna ports.
The method of claim 3, wherein the preset mapping relationship is a mapping relationship between a random access channel time resource and a random access channel frequency resource both used in the transmitting beam direction, and the RA-RNTI, and

wherein determining, the identifier for the transmission beam based on the preset mapping relatonship comprises: determining, in accordance with the mapping relationship, an RA-RNTI to which the random access channel time resource and the random access channel frequency resource both used in the transmitting beam direction with the maximum energy are mapped.
The method of claim 1, wherein the identifier for the transmission beam is a cell-radio network temporary identifier (C-RNTI), and

wherein transmitting, to the terminal, the random access response comprising the identifier for the transmission beam comprises:

determining a cell where the user equipment is located; and

selecting, from a subset of C-RNTIs for the cell, an unused C-RNTI to transmit a random access response comprising the selected C-RNTI to the user equipment.
The method of claim 1, further comprising:

before receiving, from the terminal, a preamble sequence, transmitting system configuration information to the terminal,

wherein the system configuration information comprises random access channel configuration information and a mapping relationship between a transmitting beam direction and the identifier for the transmission beam.
The method of claim 1, wherein determining the transmission beam of the terminal based on the preamble sequence received from the terminal comprises:

determining a transmitting beam direction with the maximum energy based on a result of correlation detection performed on the preamble sequence.
A method for operating a terminal in a wireless communication system, the terminal comprising:

transmitting, to a base station, a preamble sequence; and

receiving, from the base station, a random access response comprising a identifier for a transmission beam,

wherein the transmission beam is determined based on the preamble sequence, and

wherein the identifier for the transmission beam is determined based on a preset mapping relationship.
The method of claim 8, wherein the identifier is a random access-radio network temporary identifier (RA-RNTI), and

wherein receiving, from the base station, a random access response comprising the identifier for the transmission beam comprises:

calculating an RA-RNTI used for scrambling a downlink control channel; and

descrambling the downlink control channel by using the RA-RNTI to receive the random access response.
The method of claim 9, wherein transmitting, to the base station, the preamble sequence comprises transmitting a preamble sequence to the base station based on a single antenna port or multiple antenna ports.
The method of claim 10, further comprising:

determining, in accordance with the mapping relationship, a random access channel time resource and a random access channel frequency resource to which the RA-RNTI is mapped; and

determining a transmitting beam direction with the maximum energy using the random access channel time resource and the random access channel frequency resource,

wherein the preset mapping relationship is a mapping relationship between a random access channel time resource and a random access channel frequency resource both used in the transmitting beam direction, and the RA-RNTI.
The method of claim 8, wherein the identifier for the transmission beam is a cell-radio network temporary identifier (C-RNTI).
The method of claim 8, further comprising:

receiving system configuration information transmitted by the base station, the configuration information comprising random access channel configuration information and a mapping relationship between a transmitting beam direction and the identifier for the transmission beam.
A base station (BS) arranged to implement a method of any one of claims 1 to 7.
A terminal arranged to implement a method of any one of claims 8 to 13.