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WO2009116407A1 - Dispositif de station mobile et procédé de retransmission - Google Patents

Dispositif de station mobile et procédé de retransmission Download PDF

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Publication number
WO2009116407A1
WO2009116407A1 PCT/JP2009/054285 JP2009054285W WO2009116407A1 WO 2009116407 A1 WO2009116407 A1 WO 2009116407A1 JP 2009054285 W JP2009054285 W JP 2009054285W WO 2009116407 A1 WO2009116407 A1 WO 2009116407A1
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WO
WIPO (PCT)
Prior art keywords
random access
station apparatus
signature
base station
access preamble
Prior art date
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PCT/JP2009/054285
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English (en)
Japanese (ja)
Inventor
恭之 加藤
昇平 山田
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シャープ株式会社
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Publication of WO2009116407A1 publication Critical patent/WO2009116407A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/002—Transmission of channel access control information
    • H04W74/004—Transmission of channel access control information in the uplink, i.e. towards network
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H04W74/0833—Random access procedures, e.g. with 4-step access
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H04W74/0833—Random access procedures, e.g. with 4-step access
    • H04W74/0838—Random access procedures, e.g. with 4-step access using contention-free random access [CFRA]

Definitions

  • the present invention relates to a retransmission technique in a random access procedure.
  • EUTRA Evolved Universal Terrestrial Radio Access
  • DFT DiscreteOFDMFourier Transform
  • FIG. 10 is a diagram showing the configuration of the downlink and uplink channels of EUTRA.
  • the downlink of EUTRA includes downlink pilot channel DPiCH (Downlink Pilot Channel), downlink synchronization channel DSCH (Downlink Synchronization Channel), downlink shared channel PDSCH (Physical Downlink Shared Channel), downlink control.
  • DPiCH Downlink Pilot Channel
  • DSCH Downlink Synchronization Channel
  • PDSCH Physical Downlink Shared Channel
  • a channel PDCCH PhysicalCHDownlink Control Channel
  • CCPCH Common Control Physical Channel
  • the uplink of EUTRA includes uplink pilot channel UPiCH (UplinkCHPilot Channel), random access channel RACH (Random Access Channel), uplink shared channel PUSCH (Physical Uplink Shared Channel), uplink control channel PUCCH (Physical Uplink Control). Channel) (Non-Patent Documents 1 and 2).
  • UPiCH UplinkCHPilot Channel
  • RACH Random Access Channel
  • PUSCH Physical Uplink Shared Channel
  • PUCCH Physical Uplink Control
  • Channel Physical Uplink Control
  • the random access channel RACH prepares one random access channel in one subframe, and prepares a plurality of random access channels in one frame to support access from a large number of mobile station apparatuses.
  • Non-Patent Document 3 The configuration of the random access channel is notified to the mobile station apparatus as broadcast information.
  • FIG. 11 is a diagram illustrating an example of an uplink configuration. As shown in FIG. 11, the horizontal axis represents time and the vertical axis represents frequency. FIG. 11 shows the configuration of one radio frame, and this radio frame is divided into a plurality of radio resources.
  • the radio resource is configured with an area of 180 kHz in the frequency direction and 1 ms in the time direction as a unit, and the random access channel RACH, the uplink shared channel PUSCH, and the uplink control channel PUCCH are illustrated in these areas. It is assigned as follows.
  • the minimum unit of the random access channel RACH uses a band of 1080 kHz.
  • FIG. 12 is a configuration example of a random access channel. Further, the random access channel may be arranged to hop at a constant period as shown in FIG.
  • Non-Patent Document 2 The purpose of using the random access channel is to synchronize between the mobile station apparatus and the base station apparatus in the uplink, but also transmits several bits of information such as a scheduling request to allocate radio resources, It is also considered to shorten the connection time (Non-Patent Document 2).
  • Contention based Random Access is random access that may collide between mobile station apparatuses, and is normally performed random access.
  • Non-contention based Random Access is a random access that does not cause collision between mobile station devices, and in order to quickly synchronize between the mobile station device and the base station device, it is led by the base station device in special cases such as handover. Is done.
  • the preamble includes a signature which is a signal pattern representing information, and several tens of types of signatures can be prepared to express several bits of information.
  • a signature which is a signal pattern representing information
  • several tens of types of signatures can be prepared to express several bits of information.
  • 6-bit information is transmitted, and it is assumed that 64 types of signatures are prepared.
  • the 6-bit information is assumed to be assigned information such as 5 bits for random ID, and the remaining 1 bit for downlink path loss / CQI (Channel Quality ⁇ Indicator) or request transmission size of message 3 of random access procedure. ing.
  • FIG. 13 is a diagram showing a configuration example of a signature.
  • each mobile station apparatus selects at random. . From the 49th to the 64th, the base station apparatus selects and notifies the mobile station apparatus.
  • Signature selection when the message size is small is usually selected when the characteristics of the radio propagation path are poor (or the distance from the base station apparatus is far), and signature selection when the message size is large is selected for the radio propagation path. It is selected when the characteristics are good (or the distance from the base station device is short).
  • FIG. 14 is a diagram illustrating a procedure example of Contention based Random Access. As shown in FIG. 14, first, the mobile station apparatus determines a signature range to be selected from a random ID, downlink path loss / CQI information, etc., and randomly selects a signature from the selected signature range. Then, a random access preamble is transmitted on the random access channel RACH (message 1 (P1)).
  • RACH messages 1 (P1)).
  • the base station apparatus When the base station apparatus receives the preamble from the mobile station apparatus, the base station apparatus calculates a synchronization timing shift between the mobile station apparatus and the base station apparatus from the preamble, and performs scheduling (uplink) to transmit an L2 / L3 (Layer2 / Layer3) message. Radio resource location, transmission format (message size), etc.). Then, a temporary C-RNTI (Cell-Radio Network Temporary Identity) is allocated, and a RA-RNTI (Random Access-) indicating a response addressed to the mobile station apparatus that has transmitted the random access preamble to the random access channel RACH to the downlink control channel PDCCH.
  • C-RNTI Cell-Radio Network Temporary Identity
  • RA-RNTI Random Access-
  • Radio Network Temporary Identity is arranged, and the downlink shared data channel PDSCH includes synchronization timing deviation information, scheduling information, Temporary C-RNTI, and received signature ID number (also referred to as random ID or preamble ID).
  • a random access response is transmitted (message 2 (P2)).
  • the mobile station apparatus When the mobile station apparatus confirms that the downlink control channel PDCCH has RA-RNTI, the mobile station apparatus confirms the contents of the random access response arranged in the downlink shared data channel PDSCH. Then, a response including the signature ID number (also referred to as random ID or preamble ID) of the transmitted preamble is extracted, the synchronization error is corrected, and the C-RNTI (or Temporary C) is used in the scheduled radio resource and transmission format. -RNTI) or an L2 / L3 message including information for identifying a mobile station device such as IMSI (International Mobile Subscriber Identity) (message 3 (P3)).
  • IMSI International Mobile Subscriber Identity
  • the transmission power of message 3 is calculated based on the transmission power of message 1. Note that the mobile station device continues to wait for a random access response from the base station device for a certain period, and when it does not receive the random access response including the signature ID number of the transmitted preamble, it transmits the random access preamble again.
  • the base station apparatus receives the L2 / L3 message from the mobile station apparatus, there is a collision between the mobile station apparatuses using C-RNTI (or Temporary C-RNTI) or IMSI included in the received L2 / L3 message.
  • a contention resolution for determining whether or not this occurs is transmitted to the mobile station apparatus (message 4 (P4)).
  • Non-Patent Document 4 If the mobile station apparatus does not detect the signature ID number of the preamble transmitted in the random access response, the mobile station apparatus detects the message 3 transmission failure or the identification information of the own mobile station apparatus in the contention resolution. If not, the process starts again from transmission of the random access preamble (Non-Patent Document 4).
  • FIG. 15 is a diagram illustrating a procedure example of Non-Contention based Random Access. As shown in FIG. 15, first, the base station apparatus selects a signature ID number and notifies the mobile station apparatus (message 0 (Q1)). The mobile station apparatus uses the notified signature and transmits a random access preamble using a random access channel (message 1 (Q2)).
  • the base station apparatus When the base station apparatus receives the preamble from the mobile station apparatus, the base station apparatus calculates a synchronization timing shift between the mobile station apparatus and the base station apparatus from the preamble, and transmits a random access preamble to the downlink control channel PDSCH using the random access channel RACH.
  • the RA-RNTI or C-RNTI indicating the response addressed to the mobile station apparatus is arranged, and a random access response including synchronization timing deviation information is transmitted (message 2 (Q3)).
  • the mobile station apparatus corrects the synchronization timing deviation from the received random access response (Non-Patent Document 4).
  • FIG. 16 is a diagram illustrating a state in which transmission power is increased at the time of retransmission of a random access preamble. As shown in FIG. 16, when the random access procedure fails, the random access preamble is transmitted with a transmission power value obtained by adding a constant value to the transmission power of the previously transmitted random access preamble.
  • 3GPP TS (Technical Specification) 36.211, V1.10 (2007-05), Technical Specification Group Radio Access Network, Physical Channel and Modulation (Release 8)
  • 3GPP TS (Technical Specification) 36.212, V1.20 (2007-05), Technical Specification Group Radio Access Network, Multiplexing and channel coding (Release 8) R1-07436, Texas Instruments, “Random Access slot Configurations”, 3GPP TSG RAN WG1 Meeting # 50, Athens, Greene, 20-24 August, 2007
  • 3GPP TS (Technical Specification) 36.300, V8.10 (2007-06), Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Reverend ERC.
  • random access fails for the following reasons. That is, in the random access preamble (message 1), this is because the base station apparatus fails to detect the random access preamble due to the influence of the radio propagation path or the collision between the mobile station apparatuses. In addition, in the random access response (message 2), the mobile station apparatus fails to receive the random access response due to the influence of the radio propagation path. In the L2 / L3 message (message 3), the base station apparatus fails to receive the L2 / L3 message due to the influence of the radio propagation path or the collision between the mobile station apparatuses. Also, the contention resolution (message 4) is caused by the mobile station apparatus failing to receive contention resolution due to the influence of the radio propagation path.
  • the mobile station device When retransmitting random access after random access failure due to the influence of the radio propagation path, the mobile station device basically increases the transmission power to increase the reliability of random access (transmission of message 1 and message 3). Can be raised. However, simply increasing the transmission power may not be sufficient.
  • the present invention has been made in view of such circumstances, and an object of the present invention is to provide a mobile station apparatus and a communication method capable of performing highly reliable random access retransmission.
  • the mobile station apparatus of the present invention transmits a random access preamble to the base station apparatus using a random access channel in order to establish uplink synchronization with the base station apparatus.
  • a mobile station that receives a random access preamble response transmits an L2 / L3 message to the base station device based on the random access preamble response, and receives a collision confirmation from the base station device.
  • Preamble students that generate new And parts are characterized by comprising a transmitter which retransmits the random access preamble the newly generated for the base station apparatus.
  • the signature selection unit when the transmission of the L2 / L3 message fails, the signature selection unit newly selects a signature having a meaning different from the signature included in the random access preamble. It is characterized by that.
  • the transmission of the L2 / L3 message fails, a signature having a meaning different from the signature included in the random access preamble is newly selected. Therefore, the signature that is unlikely to fail the transmission of the L2 / L3 message is selected. As a result, the reliability of retransmission of the L2 / L3 message can be improved. For example, by selecting a signature indicating that the transmission size of the L2 / L3 message is small, it becomes possible to improve the reliability of the L2 / L3 message at the time of random access retransmission.
  • the signature selection unit when the transmission of the L2 / L3 message fails, the signature selection unit newly selects a signature indicating that the transmission capacity of the L2 / L3 message is small, The transmission unit retransmits an L2 / L3 message having a small transmission capacity.
  • the signature selection unit newly selects a signature to be used when a downlink radio channel condition is bad when the random access procedure fails. It is said.
  • the mobile station apparatus of the present invention transmits a random access preamble to the base station apparatus through a random access channel in order to establish uplink synchronization with the base station apparatus.
  • Random access procedure for receiving a random access preamble response from the station device, transmitting an L2 / L3 message to the base station device based on the random access preamble response, and receiving a collision confirmation from the base station device
  • the mobile station apparatus changes a threshold of a range for selecting a signature included in the random access preamble, and selects a signature based on the changed threshold and the radio propagation path state RACH control unit for determining the range and the determined signature selection range
  • a signature selecting unit for selecting a new signature; a preamble generating unit for newly generating a random access preamble including the newly selected signature; and retransmitting the newly generated random access preamble to the base station apparatus And a transmitting unit.
  • the threshold of the range for selecting the signature included in the random access preamble is changed, and the signature selection range is determined based on the changed threshold and the radio channel state. Since a new signature is selected from the selected signature selection range, it is possible to improve the reliability of random access retransmission by selecting a signature in which the random access procedure is unlikely to fail.
  • the RACH control unit when the transmission of the L2 / L3 message fails, the RACH control unit changes a threshold value for selecting a signature included in the random access preamble, and changes the threshold value.
  • the signature selection range is determined based on the threshold value and the radio propagation path state.
  • the threshold of the range for selecting the signature included in the random access preamble is changed, and the signature selection range is changed based on the changed threshold and the radio propagation path state. Therefore, it is possible to improve the reliability of retransmission of random access by selecting a signature that is unlikely to fail transmission of the L2 / L3 message.
  • the mobile station apparatus of the present invention transmits a random access preamble to the base station apparatus using a random access channel in order to establish uplink synchronization with the base station apparatus, and Random access procedure for receiving a random access preamble response from the station device, transmitting an L2 / L3 message to the base station device based on the random access preamble response, and receiving a collision confirmation from the base station device
  • a mobile station apparatus that determines a signature range for selecting a signature included in the random access preamble based on transmission power of the random access preamble, and selects a signature from the determined signature selection range
  • a signature selector to select the selected is characterized in that it comprises a transmitter which transmits a random access preamble the generated to the base station apparatus.
  • the signature range for selecting the signature included in the random access preamble is determined based on the transmission power of the random access preamble and the signature is selected from the determined signature selection range, the signature in which the random access procedure is unlikely to fail. By selecting, it is possible to improve the reliability of retransmission for random access.
  • the RACH control unit when the transmission power of the random access preamble is larger than a predetermined threshold, indicates that the transmission capacity of the L2 / L3 message is small If the transmission power of the random access preamble is smaller than a predetermined threshold, the signature selection range including a signature indicating that the transmission capacity of the L2 / L3 message is large is determined. It is characterized by.
  • the signature selection including the signature indicating that the transmission capacity of the L2 / L3 message is small.
  • the signature selection range including the signature indicating that the transmission capacity of the L2 / L3 message is large is set.
  • the retransmission method of the present invention transmits a random access preamble to the base station apparatus through a random access channel in order to establish uplink synchronization with the base station apparatus, and A random access preamble response is received from the device, an L2 / L3 message is transmitted to the base station device based on the random access preamble response, and a collision check is received from the base station device.
  • a retransmission method of a mobile station apparatus wherein if the random access procedure fails, a new signature having a meaning different from the signature included in the random access preamble is selected, and the random access preamble including the newly selected signature is selected. Newly generated, and the newly generated lander It is characterized in that retransmits an access preamble to the base station apparatus.
  • a signature having a meaning different from the signature included in the random access preamble is newly selected. It is possible to improve the reliability of retransmission.
  • FIG. 3 is a flowchart showing an operation of the mobile station apparatus according to the first embodiment.
  • 3 is a flowchart showing an operation of the mobile station apparatus according to the first embodiment.
  • 6 is a flowchart showing an operation of the mobile station apparatus according to the second embodiment.
  • 6 is a flowchart showing an operation of the mobile station apparatus according to the second embodiment. 6 is a flowchart showing an operation of selecting a signature of the mobile station apparatus according to the second embodiment. It is a figure which shows the structural example of a signature. It is a figure which shows the structure of the channel of EUTRA downlink and an uplink. It is a figure which shows the structural example of an uplink. It is a structural example of a random access channel. It is a figure which shows the structural example of a signature. It is a figure which shows the example of a procedure of Contention based Random Access. It is a figure which shows the example of a procedure of Non-Contention based Random Access. It is a figure which shows a mode that transmission power is increased at the time of retransmission of a random access preamble.
  • the arrangement positions of the random access channels are arranged at regular intervals on the time axis as shown in FIG. 11, and have one random access channel (random access resource) on the frequency axis. Assume a system. Note that hopping may be performed at regular intervals between the low frequency band and the high frequency band. Further, the procedure of Random Access assumes the procedure of FIG.
  • the failure of Random Access in message 3 transmission is assumed to be due to the influence of fluctuations in the radio propagation path or the collision between mobile station apparatuses.
  • the message 3 transmission failure due to the influence of the fluctuation of the radio propagation path has different reliability depending on whether the message size to be transmitted is large or small.
  • the message size is large, it is used when the characteristics of the radio propagation path are good, but the modulation multi-level number and coding rate are high, and it is easily affected by the radio propagation path.
  • the message size is small, it is used when the radio propagation path characteristics are poor, but the modulation multi-value number and coding rate are low, so that it is not easily affected by the radio propagation path.
  • the characteristics of the radio propagation path are calculated from the characteristics of the downlink, it is possible to determine only characteristics that are close to a good or bad wireless environment, or far from the base station apparatus.
  • message 3 at the time of retransmission selects a format indicating that the message size is small, and transmits message 1 (random access preamble). Further, in order to increase the reliability of the Random Access procedure at the time of retransmission, a message 3 having a small message size at the time of retransmission is used.
  • the mobile station apparatus selects a signature from signatures indicating that the message size is small, and transmits a random access preamble including the selected signature.
  • a signature is always selected from signatures indicating that the message size is small, and a random access preamble including the selected signature is transmitted.
  • signatures having different meanings are signatures belonging to different groups.
  • a threshold value (X, Y) of the radio propagation path characteristic is provided, and when the message 1 (random access preamble) is initially transmitted, the radio propagation path characteristic is better than the threshold value X and the message size is transmitted.
  • a format indicating that the message size is large is selected, and when retransmission of the message 3 fails, the radio channel characteristics are better than the threshold Y, and it is necessary to send a large message size.
  • the threshold value is further changed using the transmission power of the random access preamble. In this case, the threshold value can be changed from (X, Y) to (S, T) according to the transmission power of the random access preamble.
  • the failure is specified in the transmission of the message 3, but it may be applied to the case of the failure in the processing after the transmission of the message 3. Furthermore, the present invention may be applied to the case where the transmission of message 1 has failed (the reception failure of message 2).
  • FIG. 1 is a block diagram showing a schematic configuration of a base station apparatus according to this embodiment.
  • the base station apparatus 1 includes a data control unit 2, an OFDM modulation unit 3, a scheduling unit 4, a channel estimation unit 5, a DFT-Spread-OFDM demodulation unit 6, a control data extraction unit 7, a preamble detection unit 8, and a synchronization timing measurement unit 9 , And the radio unit 10.
  • the scheduling unit 4 includes a DL scheduling unit 4a, a UL scheduling unit 4b, and a control data creation unit 4c.
  • the data control unit 2 controls the input user data and control data according to an instruction from the scheduling unit 4. That is, control data is mapped to downlink control channel PDCCH, downlink synchronization channel DSCH, downlink pilot channel DPiCH, common control signaling channel CCPCH, downlink shared channel PDSCH, and transmission data for each mobile station apparatus is downlink shared channel Map to PDSCH.
  • the OFDM modulation unit 3 performs OFDM signal processing such as data modulation, serial / parallel conversion of input signals, IFFT (Inverse Fast Fourier Transform) conversion, CP (Cyclic Prefix) insertion, filtering, and the like to generate an OFDM signal.
  • the radio unit 10 up-converts OFDM-modulated data to a radio frequency and transmits it to the mobile station apparatus.
  • the radio unit 10 receives uplink data from the mobile station apparatus, down-converts it into a baseband signal, and converts the received data into a DFT-Spread-OFDM demodulation unit 6, a channel estimation unit 5, and a preamble detection unit 8 Output to.
  • the channel estimation unit 5 estimates the radio channel characteristics from the uplink pilot channel UPiCH, and outputs the radio channel estimation result to the DFT-Spread-OFDM demodulation unit 6. Further, the channel estimation unit 5 outputs a radio channel estimation result to the scheduling unit 4 in order to perform uplink scheduling from the uplink pilot channel UPiCH.
  • the uplink communication scheme is assumed to be a single carrier scheme such as DFT-Spread-OFDM, but a multicarrier scheme such as the OFDM scheme may be used.
  • the control data extraction unit 7 confirms whether the received data is correct and notifies the scheduling unit 4 of the confirmation result. If the received data is correct, the received data is separated into user data and control data. Among the control data, layer 2 control data such as downlink CQI information and downlink data ACK / NACK are output to the scheduling unit 4, and other layer 3 control data and user data are output to the upper layer. Is done. If the received data is incorrect, the control data extracting unit 7 stores the received data for combining with the retransmitted data, and performs a combining process when the retransmitted data is received.
  • layer 2 control data such as downlink CQI information and downlink data ACK / NACK are output to the scheduling unit 4
  • other layer 3 control data and user data are output to the upper layer. Is done. If the received data is incorrect, the control data extracting unit 7 stores the received data for combining with the retransmitted data, and performs a combining process when the retransmitted data is received.
  • the scheduling unit 4 includes a DL scheduling unit 4a that performs downlink scheduling, a UL scheduling unit 4b that performs uplink scheduling, and a control data creation unit 4c.
  • the DL scheduling unit 4a transmits user data and control data to each downlink channel from CQI information notified from the mobile station apparatus, data information of each user notified from the higher layer, and control data generated by the message generating unit.
  • Schedule for mapping The UL scheduling unit 4b performs scheduling for mapping user data to each uplink channel from the uplink radio channel estimation result from the channel estimation unit 5 and the resource allocation request from the mobile station apparatus.
  • the control data creation unit 4c stores information on random access such as uplink ACK / NACK, random access channel configuration (random access opportunity, hopping pattern, etc.) and information indicating the transmission status of random access (random access load). Control data such as a broadcast information message, a random access response message, and a contention resolution message are generated.
  • the preamble detection unit 8 detects the preamble, calculates the synchronization timing shift amount, and reports the signature ID number and the synchronization timing shift amount to the scheduling unit 4. Further, the scheduling unit 4 is also notified of the random access transmission status of the mobile station apparatus periodically from the number of received random access preambles. Further, the transmission range of the preamble retransmission (number of random access channels or the number of frames) is calculated from the transmission status of the random access preamble transmission, and is notified to the scheduling unit 4.
  • the synchronization timing measurement unit 9 measures the uplink pilot channel UPiCH to maintain synchronization, measures the synchronization timing deviation, and reports the measurement result to the scheduling unit 4.
  • FIG. 2 is a block diagram showing a schematic configuration of the mobile station apparatus according to the present embodiment.
  • the mobile station apparatus 20 includes a data control unit 21, a DFT-S-OFDM modulation unit 22, a scheduling unit 23, an OFDM demodulation unit 24, a channel estimation unit 25, a control data extraction unit 26, a synchronization correction unit 27, a preamble generation unit 28, A signature selection unit 29 and a radio unit 30 are included.
  • the scheduling unit 23 includes a UL scheduling unit 23a, a control data analysis unit 23b, a control data creation unit 23c, and a RACH control unit 23d.
  • User data and control data are input to the data control unit 21.
  • the data control unit 21 is arranged so that user data and control data are transmitted by the uplink shared channel PUSCH and the uplink control channel PUCCH according to an instruction from the scheduling unit 23. Also, an uplink pilot channel UPiCH is arranged.
  • the DFT-S-OFDM modulation unit 22 performs data modulation, performs DFT-S-OFDM signal processing such as DFT conversion, subcarrier mapping, IFFT conversion, CP (Cyclic Prefix) insertion, filtering, and the like, and DFT-Spread-OFDM signal Is generated.
  • DFT-S-OFDM signal processing such as DFT conversion, subcarrier mapping, IFFT conversion, CP (Cyclic Prefix) insertion, filtering, and the like
  • DFT-Spread-OFDM signal Is generated As an uplink communication method, a single carrier method such as DFT-Spread-OFDM is assumed, but a multicarrier method such as an OFDM method may be used.
  • the synchronization correction unit 27 corrects the transmission timing from the synchronization information input from the control data extraction unit 26 and outputs data modulated to match the transmission timing to the radio unit 30.
  • Radio section 30 sets a predetermined radio frequency to a frequency to be used, up-converts the modulated data to a radio frequency, and transmits the radio data to the base station apparatus. Also, the radio unit 30 receives downlink data from the base station apparatus, down-converts it into a baseband signal, and outputs the received data to the OFDM demodulation unit 24.
  • the channel estimation unit 25 estimates the radio channel characteristics from the downlink pilot channel DPiCH and outputs the estimation result to the OFDM demodulation unit 24. In addition, in order to notify the base station apparatus of the radio channel estimation result, the base station apparatus converts it to CQI information, and outputs the CQI information to the scheduling unit 23.
  • the OFDM demodulator 24 demodulates the received data from the radio channel estimation result of the channel estimator 25.
  • the control data extraction unit 26 separates the received data into user data and control data.
  • the control data extraction unit 26 outputs uplink synchronization information in the control data to the synchronization correction unit 27, and outputs scheduling information and other layer 2 control data to the scheduling unit 23. Also, the control data and user data of layer 3 are output to the upper layer.
  • the signature selection unit 29 randomly selects a signature ID number used for random access from the range of signature IDs specified by the scheduling unit 23, and outputs the selected signature ID number to the preamble generation unit 28.
  • the preamble generation unit 28 generates a random access preamble including a signature corresponding to the signature ID number selected by the signature selection unit 29 and outputs the random access preamble to the DFT-S-OFDM modulation unit 22.
  • the scheduling unit 23 includes a UL scheduling unit 23a, a control data analysis unit 23b, a control data creation unit 23c, and a RACH control unit 23d.
  • the control data analysis unit 23b analyzes the control information of the control data input from the control data extraction unit 26, outputs the scheduling information to the UL scheduling unit 23a, and receives the synchronization timing shift information included in the random access response and the synchronization information.
  • the synchronization correction unit 27 outputs a broadcast information message including information on random access transmission such as information indicating the configuration of the random access channel and the transmission status of the random access to the signature selection unit 29 and the RACH control unit 23d. Further, the control data creation unit 23c is instructed to return ACK.
  • the control data creation unit 23 c creates ACK / NACK and other control data and outputs them to the data control unit 21.
  • the UL scheduling unit 23a instructs the data control unit 21 to map data and control information to each uplink channel from scheduling information input from an upper layer and control information input from the control data analysis unit 23b. .
  • the RACH control unit 23d determines a range of signature IDs to be selected from the notified random access transmission-related information, the downlink radio channel characteristics, and the retransmission status (such as the status of which message has failed), and the signature selection Notify unit 29. Further, the position (time position) of the random access channel RACH is selected. In addition, the scheduling unit 23 instructs the signature selection unit 29 to perform random access according to an instruction from the upper layer.
  • 3A and 3B are flowcharts showing the operation of the mobile station apparatus according to the first embodiment.
  • the mobile station apparatus acquires information on random access broadcast from the base station apparatus (step S1), and resets the number of random access transmissions (step S2). Then, the random access channel selection process starts. In the case of initial transmission, the random access channel closest in time is selected from the configuration of the random access channel in the acquired information regarding random access (step S3). In the case of retransmission, the time position of the nearest random access channel is confirmed (step S3).
  • a signature to be included in the random access preamble is selected (step S4), a random access preamble is generated, and the random access preamble is transmitted through the selected random access channel (step S5). After transmitting the random access preamble, the random access response is received.
  • step S6 It is determined whether a random access response included in the signature ID number of the random access preamble transmitted during the random access response reception period has been received (step S6). If not received, retransmission preparation processing is performed. That is, in the retransmission preparation process, it is determined whether or not the maximum number of random access transmissions (the maximum number of random access preambles including retransmissions performed in one random access) has been exceeded (step S7). If so, the upper layer is notified (step S8), and the random access is terminated.
  • step S9 the number of random access transmissions is counted up.
  • step S10 A random access channel time position within a certain range is selected at random, and the system waits until the selected time position (step S10). Subsequently, the process proceeds to step S3 to enter a random access channel selection process.
  • step S6 if a random access response including the signature ID number of the random access preamble transmitted by the mobile station apparatus is received within the random access response reception period, the L2 / L3 message transmission process is executed. That is, before transmitting the L2 / L3 message, the uplink transmission timing is corrected from the synchronization timing shift information included in the random access response (step S11). Next, an L2 / L3 message is created (step S12), and the L2 / L3 message is transmitted to the base station apparatus (step S13). A response to the L2 / L3 message is confirmed from the base station apparatus (step S14). When the transmission of the L2 / L3 message is successful, the contention resolution message is received from the contention resolution message reception period and the base station apparatus. wait. When the contention resolution message is received (step S15), the random access is terminated.
  • step S14 if transmission of the L2 / L3 message fails in step S14, the process proceeds to step S7, and retransmission preparation processing is performed. If no contention resolution message is received in step S15, the process proceeds to step S7 to perform retransmission preparation processing.
  • FIG. 4 is a flowchart showing the operation of signature selection in the mobile station apparatus.
  • the mobile station apparatus determines whether it is initial transmission or retransmission of the random access preamble (step T1), and in the case of retransmission, it next determines whether it is retransmission due to message 3 transmission failure (step T2). In the case of retransmission due to failure in message 3 transmission, a range with a small message transmission size is selected, and a signature is randomly selected from the selected range with a small message transmission size (step T3).
  • step T2 a signature selection range is determined from the measured downlink radio channel characteristics, and a signature is randomly selected from the selected signature range.
  • Select step T4.
  • step T1 in the case of initial transmission, a signature selection range is determined from the measured downlink radio channel characteristics, and a signature is randomly selected from the selected signature range (step T4). ).
  • FIG. 5 is a flowchart showing another operation of signature selection in the mobile station apparatus.
  • the mobile station apparatus determines whether the random access preamble is initially transmitted or retransmitted (step T5). In the case of retransmission, the mobile station apparatus preempts the range with a small message transmission size and selects from the selected range with a small message transmission size. A signature is selected at random (step T6). On the other hand, in the case of initial transmission, a signature selection range is determined from the measured downlink radio propagation path condition, and a signature is randomly selected from the selected signature range (step T7).
  • FIG. 6 is a flowchart showing another operation of signature selection in the mobile station apparatus.
  • the mobile station apparatus determines whether the random access preamble is initially transmitted or retransmitted (step T8). If retransmitted, the mobile station apparatus determines whether it is retransmitted due to message 3 transmission failure (step T9). In the case of retransmission due to message 3 transmission failure, a signature selection range is determined from the radio propagation path characteristics and threshold Y, and a signature is randomly selected from the selected signature range (step T10).
  • step T8 a signature selection range is determined from the measured downlink radio channel characteristics, and a signature is randomly selected from the selected signature range (step T11). ).
  • step T9 in the case of retransmission other than message 3 transmission failure, a signature selection range is determined from the measured downlink radio channel characteristics, and a signature is randomly selected from the selected signature range. Select (step T11).
  • the base station apparatus When the base station apparatus receives the random preamble from the mobile station apparatus, the base station apparatus calculates a synchronization timing shift between the mobile station apparatus and the base station apparatus from the preamble, and performs scheduling to transmit an L2 / L3 (Layer2 / Layer3) message. Then, a temporary C-RNTI (Cell-Radio Network Temporary Identity) is allocated, and a RA-RNTI (Random K Access-Radio) indicating a response addressed to the mobile station apparatus that has transmitted the random access preamble to the random access channel RACH to the downlink control channel PDCCH.
  • L2 / L3 Layer2 / Layer3
  • a temporary C-RNTI Cell-Radio Network Temporary Identity
  • RA-RNTI Random K Access-Radio
  • Network Temporary Identity is arranged, and a random access response including synchronization timing shift information, scheduling information, Temporary C-RNTI, and signature ID number of the received preamble is transmitted to the downlink shared data channel PDSCH.
  • the contention resolution is transmitted to the mobile station apparatus.
  • the procedure of Random Access assumes the procedure of FIG.
  • the failure of Random Access in message 3 transmission is assumed to be due to the influence of fluctuations in the radio propagation path or the collision between mobile station apparatuses.
  • the message 3 transmission failure due to the influence of the fluctuation of the radio propagation path has different reliability depending on whether the message size to be transmitted is large or small. When the message size is large, it is used when the characteristics of the radio propagation path are good, but the modulation multi-level number and coding rate are high, and it is easily affected by the radio propagation path.
  • the message size is small, it is used when the radio propagation path characteristics are poor, but the modulation multi-value number and coding rate are low, so that it is not easily affected by the radio propagation path.
  • the radio propagation path characteristic of the downlink is used as the characteristic of the radio propagation path, it is possible to judge only the characteristic of the degree that the radio environment is good or bad, or the distance from the base station apparatus is long or close.
  • the signature included in the random access preamble is determined based on the downlink radio propagation path characteristics, and is determined at random from the determined signature range. Also, the transmission power of random access preamble transmission is calculated based on the downlink radio propagation path characteristics, and the transmission power of the L2 / L3 message is also determined based on the transmission power of the successful random access preamble.
  • the signature and transmission power are determined based on the downlink radio propagation path characteristics. However, if the first random access fails, the transmission power for the second and subsequent transmissions is transmitted in the previous time. A power value obtained by adding a certain value to the transmitted power is used, and there is a mismatch between the signature selection and the transmission power, which is likely to lead to failure in transmission of the message 3. For this reason, it is necessary to prevent a mismatch between signature selection and transmission power.
  • the mismatch between the signature selection and the transmission power does not occur. Specifically, after determining the transmission power of the random access preamble, it is determined based on the transmission power of the random access preamble whose signature usage range has been determined, and the signature is randomly determined from the determined signature usage range.
  • the configuration of the base station apparatus is the same as that of the base station apparatus according to the first embodiment described with reference to FIG. Also, the configuration of the mobile station apparatus is the same as that of the first embodiment described with reference to FIG.
  • user data and control data are input to the data control unit 21.
  • the data control unit 21 is arranged so as to be transmitted through the uplink shared channel PUSCH and the uplink control channel PUCCH according to an instruction from the scheduling unit 23. Also, an uplink pilot channel UPiCH is arranged.
  • the DFT-S-OFDM modulation unit 22 performs data modulation, performs DFT-S-OFDM signal processing such as DFT conversion, subcarrier mapping, IFFT conversion, CP (Cyclic Prefix) insertion, filtering, and the like, and DFT-Spread-OFDM signal Is generated.
  • DFT-S-OFDM signal processing such as DFT conversion, subcarrier mapping, IFFT conversion, CP (Cyclic Prefix) insertion, filtering, and the like
  • DFT-Spread-OFDM signal Is generated As an uplink communication method, a single carrier method such as DFT-Spread OFDM is assumed, but a multicarrier method such as an OFDM method may be used.
  • the synchronization correction unit 27 corrects the transmission timing from the synchronization information input from the control data extraction unit 26 and outputs data modulated to match the transmission timing to the radio unit 30.
  • the radio unit 30 sets a predetermined radio frequency to a frequency to be used, up-converts the modulated data to the radio frequency, sets the designated power, and transmits the power to the base station apparatus. Further, the radio unit 30 receives downlink data from the base station apparatus, down-converts the data to a baseband signal, and outputs the received data to the OFDM demodulation unit 24.
  • the channel estimation unit 25 estimates the radio channel characteristics from the downlink pilot channel DPiCH and outputs the estimation result to the OFDM demodulation unit 24. In addition, in order to notify the base station apparatus of the radio channel estimation result, the base station apparatus converts it to CQI information and outputs the CQI information to the scheduling unit 23.
  • the OFDM demodulator 24 demodulates the received data from the radio channel estimation result of the channel estimator 25.
  • the control data extraction unit 26 separates the received data into user data and control data.
  • the control data extraction unit 26 outputs uplink synchronization information in the control data to the synchronization correction unit 27, and outputs scheduling information and other layer 2 control data to the scheduling unit 23. Also, the control data and user data of layer 3 are output to the upper layer.
  • the signature selection unit 29 randomly selects a signature ID number used for random access from the range of signature IDs specified by the scheduling unit 23, and outputs the selected signature ID number to the preamble generation unit 28.
  • the preamble generation unit 28 generates a random access preamble including a signature corresponding to the signature ID number selected by the signature selection unit 29 and outputs the random access preamble to the DFT-S-OFDM modulation unit 22.
  • the control data analysis unit 23b analyzes the control information from the control data extraction unit 26, outputs the scheduling information to the UL scheduling unit 23a, and synchronizes the synchronization timing shift information included in the random access response or the synchronization information. Output to the correction unit 27.
  • a broadcast information message including information related to random access transmission such as information indicating the configuration of the random access channel and the transmission status of the random access is output to the signature selection unit 29 and the RACH control unit 23d.
  • the control data creation unit 23c is instructed to return ACK.
  • the control data creation unit 23 c creates ACK / NACK and other control data and outputs them to the data control unit 21.
  • the UL scheduling unit 23a instructs the data control unit 21 to map data and control information to each uplink channel from scheduling information input from an upper layer and control information input from the control data analysis unit 23b. .
  • the RACH control unit 23d determines a signature ID range to be selected from the notified random access transmission related information and random access preamble transmission power, and notifies the signature selection unit 29 of the range. Further, the position (time position) of the random access channel RACH is selected. Also, the transmission power of the random access preamble is determined and notified to the radio unit 30.
  • the scheduling unit 23 instructs the signature selection unit 29 to perform random access according to an instruction from the upper layer.
  • the mobile station apparatus acquires information on random access broadcast from the base station apparatus (step P1), and resets the number of random access transmissions (step P2). Then, the random access channel selection process starts. In the case of initial transmission, the random access channel closest in time is selected from the configuration of the random access channel in the acquired information regarding random access (step P3). In the case of retransmission, the time position of the nearest random access channel is confirmed (step P3).
  • the initial transmission power is calculated from the transmission power information in the acquired random access information and the downlink radio propagation path characteristics (step P4).
  • the transmission power value is calculated by adding a constant value ⁇ to the transmission power value transmitted last time (step P4).
  • a signature to be included in the random access preamble is selected based on the transmission power value of the random access preamble (step P5), a random access preamble is generated, and the random access preamble is transmitted through the selected random access channel. (Step P6). After transmitting the random access preamble, the random access response is received.
  • step P7 It is determined whether a random access response included in the signature ID number of the random access preamble transmitted during the random access response reception period has been received (step P7). If not received, retransmission preparation processing is performed. That is, in the retransmission preparation process, it is determined whether or not the maximum number of random access transmissions (the maximum number of random access preambles including retransmissions performed in one random access) has been exceeded (step P8). If this happens, the upper layer is notified (step P9) and the random access is terminated.
  • step P8 the number of random access transmissions is counted up (step P10).
  • a random access channel time position within a certain range is selected at random, and the process waits until the selected time position (step P11). Subsequently, the process proceeds to step P3, and a random access channel selection process is started.
  • Step P7 when a random access response including the signature ID number of the random access preamble transmitted by the mobile station apparatus is received within the random access response reception period, the transmission process of the L2 / L3 message is executed. That is, before transmitting the L2 / L3 message, the uplink transmission timing is corrected from the synchronization timing shift information included in the random access response (step P12). The transmission power for transmitting the L2 / L3 message is calculated based on the transmission power of the random access preamble (step P13), the L2 / L3 message is created (step P14), and the base station apparatus transmits the L2 / L3 message with the calculated transmission power. An L3 message is transmitted (step P15).
  • step P16 When a response to the L2 / L3 message is confirmed from the base station apparatus (step P16) and the transmission of the L2 / L3 message is successful, a contention resolution message reception period, a contention resolution message from the base station apparatus are displayed. Wait (step P17). When the contention resolution message is received, the random access is terminated. On the other hand, if transmission of the L2 / L3 message fails in step P16, the process proceeds to step P8, and retransmission preparation processing is performed. If no contention resolution message is received in step P17, the process proceeds to step P8 to perform retransmission preparation processing.
  • FIG. 8 is a flowchart showing the signature selection operation of the mobile station apparatus according to the second embodiment.
  • the mobile station apparatus determines whether the power of the calculated random access preamble is larger or smaller than a threshold A for determining a signature group (step Q1).
  • a threshold A for determining a signature group
  • the transmission power is larger than the threshold A
  • a signature range with a small message transmission size is selected, and a signature is randomly selected from the selected signature range with a small message transmission size (step Q1).
  • the transmission power is smaller than the threshold A in step Q1
  • a signature range with a large message transmission size is selected, and a signature is randomly selected from the selected signature range with a large message transmission size (step Q2).
  • FIG. 9 is a diagram showing a configuration example of a signature.
  • each mobile station apparatus selects at random and numbers 49 to 64 are selected when the base station apparatus performs a handover or the like, and notifies the mobile station apparatus.
  • the transmission power of the random access preamble When the transmission power of the random access preamble is large, it indicates that the L2 / L3 message size is small, and when the transmission power of the random access preamble is small, it indicates that the L2 / L3 message size is large. That is, when the transmission power is larger than the threshold A, it is considered that the propagation path state is bad. Therefore, the “signature indicating that the transmission size of the message 3 is small” which is selected when the propagation path state is bad can be selected. Thus, by selecting a signature according to transmission power, a mismatch between signature selection and transmission power is avoided. On the other hand, when the transmission power is smaller than the threshold A, it is considered that the propagation path state is good. Therefore, the “signature indicating that the transmission size of the message 3 is large” which is selected when the propagation path state is good can be selected.
  • a signature having a meaning different from the signature included in the random access preamble is newly selected. By selecting, it becomes possible to improve the reliability of retransmission of random access.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Selon l'invention, il est possible d'effectuer une retransmission d'accès aléatoire extrêmement fiable. L'invention porte sur un dispositif de station mobile (20) qui exécute un processus d'accès aléatoire vers un dispositif de station de base. Le dispositif de station mobile (20) comprend : une unité de sélection de signature (29) qui sélectionne une nouvelle signature différente d'une signature contenue dans un préambule d'accès aléatoire lorsque le processus d'accès aléatoire a échoué ; une unité de génération de préambule (28) qui génère un nouveau préambule d'accès aléatoire contenant la nouvelle signature sélectionnée ; et une unité radio (30) qui retransmet le nouveau préambule d'accès aléatoire généré au dispositif de station de base.
PCT/JP2009/054285 2008-03-21 2009-03-06 Dispositif de station mobile et procédé de retransmission WO2009116407A1 (fr)

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WO2012005335A1 (fr) * 2010-07-08 2012-01-12 株式会社エヌ・ティ・ティ・ドコモ Procédé de communication mobile et station de base sans fil
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JP2014506758A (ja) * 2011-02-14 2014-03-17 アルカテル−ルーセント オーバーヘッドを削減した短いメッセージ伝送のための方法
WO2018088422A1 (fr) * 2016-11-11 2018-05-17 シャープ株式会社 Équipement terminal, station de base, procédé de communication et circuit intégré
CN110178438A (zh) * 2016-11-11 2019-08-27 夏普株式会社 终端装置、基站装置、通信方法及集成电路
US10986668B2 (en) 2016-11-11 2021-04-20 Sharp Kabushiki Kaisha Terminal apparatus, base station apparatus, communication method, and integrated circuit

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