WO2017003208A1

WO2017003208A1 - Pmi transmitting method, pmi receiving method and devices thereof

Info

Publication number: WO2017003208A1
Application number: PCT/KR2016/007020
Authority: WO
Inventors: Ranran Zhang; Jingxing Fu; Ang YANG; Xin GUI; Meifang Jing; Jianfei CAO
Original assignee: Samsung Electronics Co., Ltd.
Priority date: 2015-06-30
Filing date: 2016-06-30
Publication date: 2017-01-05
Also published as: CN106330272A

Abstract

The present disclosure provides a precoding matrix indicator (PMI) receiving method, which may include as follows. First codebook subset restriction (CSR) signaling is transmitted, where the first CSR signaling indicates an available PMI set of all the PMIs. Second CSR signaling is transmitted, where the second CSR signaling indicates an available PMI set for a user equipment (UE), on the basis of the first CSR signaling. Channel state information (CSI) reported by the UE is received. The CSI carries a PMI obtained by the UE, after referring to the first CSR signaling and second CSR signaling. A PMI transmitting method, a PMI receiving device and a PMI transmitting device are also provided. By using the technical solutions in the present disclosure, PMI feedback problem in a multi-user (MU) multiple input multiple output (MIMO) system may be solved.

Description

PMI TRANSMITTING METHOD, PMI RECEIVING METHOD AND DEVICES THEREOF

The present disclosure relates to wireless communication technologies, and more particularly, to a precoding matrix indicator (PMI) transmitting method, a PMI receiving method and devices thereof.

In a multiple input multiple output (MIMO) mobile communication system, a wireless fading channel possesses time-varying characteristics. It is necessary to obtain channel information, so as to effectively transmit signals, implement user scheduling, space precoding, modulation and coding scheme (MCS) selection, and so on. To obtain channel information, an evolved Node B (eNB) transmits control signaling, so as to indicate a user equipment (UE) to feed back corresponding channel state information (CSI).

The eNB controls time and frequency resources, which are adopted by the UE to report the CSI. In a long-term evolution (LTE) system, the CSI includes a rank indication (RI), a channel quality indicator (CQI), a precoding matrix indicator (PMI) and a precoding type indicator (PTI).

The RI is to indicate a valid data layer number of a physical downlink shared channel (PDSCH). A supportable valid data layer number is greater, accompanying with a better signal quality.

The CQI represents current channel quality, which corresponds to a channel signal-to-noise ratio (SNR) value.

The PMI is to indicate an index of a precoding matrix in a codebook.

The PTI is to indicate a precoding feedback type.

The PMI is to recommend a precoding matrix to an eNB. The recommended precoding matrix comes from a codebook. The codebook consists of some predefined precoding matrixes. Each precoding matrix corresponds to one index, or a group of indexes. The eNB may search out a unique precoding matrix from a predefined codebook through PMI feedback.

A UE may estimate a downlink channel from an eNB to the UE, by measuring downlink channels. Subsequently, the UE may determine RI and PMI matching the downlink channel, based on the downlink channel. However, the UE cannot estimate other downlink channels from the eNB to other UEs. Thus, a higher strength of received signal may be obtained by the downlink transmission, which is from the eNB to the UE, by using the RI and PMI recommended by the UE. However, at this time, a greater interference may be generated for users in the same cell or in an adjacent cell. Thus, from the standpoint of system, the RI and PMI recommended by the UE may be not appropriate.

To solve such problem, a codebook subset restriction (CSR) mechanism has been introduced to the LTE system. The CSR includes multiple bits. Each bit corresponds to a precoding matrix, or a group of precoding matrixes in a codebook. A precoding matrix, or a group of precoding matrixes in a codebook may be disabled, by setting a bit in the CSR to 0. Subsequently, a UE is only allowed to report a PMI, which corresponds to a precoding matrix permitted by the CSR. Table 1 lists a corresponding relationship between a transmission mode and a bit number, which is needed by the CSR in an available transmission mode.

Table 1

	bit nummber
	2 antenna ports	4 antenna ports	8 antenna ports
transmission mode 3	2	4
transmission mode 4	6	64
transmission mode 5	4	16
transmission mode 6	4	16
transmission mode 8	6	the bit number is 64, when configuring alternativeCodeBookEnabledFor4TX-r12=TRUE; otherwise, the bit number is 32
transmission mode 9 and 10	6	the bit number is 96, when configuring alternativeCodeBookEnabledFor4TX-r12=TRUE; otherwise, the bit number is 64	109

Table 1: bit number needed by CSR in an available transmission mode

In the LTE system, the eNB issues the CSR with radio resource control (RRC) signaling. The CSR allows the PMI feedback to use one subset of a precoding matrix set in a codebook. However, in the PMI feedback, the PMI still uses a corresponding relationship, which is between a precoding matrix in a precoding matrix set of a codebook and a precoding matrix index. Thus, the CSR value does not have an impact on the bit number needed by the PMI feedback.

Accompanying with development of antenna technologies, especially the development of active antenna array, a physical antenna element is not only distributed in the horizontal dimension, but also distributed in the vertical dimension and horizontal dimension, so as to form a 2-dimensional (2-D) antenna array. As shown in FIG.1 and FIG.2, N represents antenna number of horizontal single polarization direction, and M represents antenna number in the vertical dimension. FIG.1 illustrates a cross-polarized 2-D antenna array. FIG.2 illustrates a single polarized 2-D antenna array.

From one aspect, a higher order multi-user (MU) transmission with vertical dimensional beam forming becomes possible, accompanying with the occurrence of 2-D antenna array. The MU transmission refers to transmitting a signal to multiple UEs simultaneously, by using the same time frequency resources. However, the higher order MU transmission with vertical dimensional beam forming may result in frequent interference changes within a system.

From another aspect, the 2-D antenna array may lead to a large-amplitude increasing to the eNB antenna number. Subsequently, codebook size (number of included precoding matrixes) will also be increased significantly. The overhead in the CSR will also be greatly increased.

Accompanying with applications of 2-D antenna array, Full Dimension MIMO (FD-MIMO) becomes possible. Compared with antenna number of MIMO system, antenna number of FD-MIMO system is increased significantly. Subsequently, codebook size of the FD-MIMO system is increased greatly, and the order of MU transmission in the FD-MIMO system is also increased. Subsequently, an original mechanism for issuing CSR with RRC signaling may be faced with some new problems.

1) Current semi-static mechanism for issuing CSR with RRC signaling is not applicable for interference coordination requirements, which may be resulted from rapid interference changes in the FD-MIMO system.

2) Simple improvement of CSR issuing mechanism with downlink control information (DCI) mode becomes infeasible, since CSR overhead is increased greatly, accompanying with increasing number of eNB antenna number.

3) Current CSR mechanism is not helpful to reduce PMI feedback overhead. It is necessary to employ an effective mode to reduce the PMI feedback overhead, since the PMI feedback overhead will be increased greatly, accompanying with increasing number of eNB antenna number.

Gain of omnidirectional MIMO mainly comes from MU-MIMO. Compared with a single-user MIMO system, to better eliminate interferences among users, the MU-MIMO system needs a PMI with higher accuracy. In current LTE/LTE-advanced (LTE-A) system, the PMI overhead may be reduced by codebook sub-sampling. Meanwhile, accuracy of PMI may be reduced, which may greatly reduce performances of MU-MIMO. Subsequently, gain of omnidirectional MIMO system may also be reduced. Thus, current codebook sub-sampling is not applicable to the omnidirectional MIMO system.

The present disclosure provides a PMI transmitting method, a PMI receiving method, and corresponding devices. Subsequently, the PMI feedback problem in a MU MIMO system may be solved.

The present disclosure provides a PMI receiving method, including:

transmitting first CSR signaling, wherein the first CSR signaling indicates an available PMI set of all the PMIs;

transmitting second CSR signaling, wherein the second CSR signaling indicates an available PMI set for a UE, on the basis of the first CSR signaling; and,

receiving CSI reported by the UE, wherein the CSI includes a PMI obtained by the UE, after referring to the first CSR signaling and the second CSR signaling.

Preferably, a second frequency transmitting the second CSR signaling is greater than, or equal to a first frequency transmitting the first CSR signaling.

Preferably, the method further includes:

after transmitting the first CSR signaling, receiving a reception acknowledge signal of the first CSR signaling from the UE.

Preferably, wherein the second CSR signaling indicates the available PMI set for the UE, on the basis of the first CSR signaling, includes:

indicating, by the second CSR signaling, the available PMI set in the first CSR signaling; or,

indicating, by the second CSR signaling, a first available PMI in the first CSR signaling, wherein the first available PMI and subsequent (N-1) PMIs are available PMIs, a total number N of the available PMIs is predefined; or,

indicating, by the second CSR signaling, a bit offset of a PMI set allowed by the first CSR signaling.

Preferably, the second CSR signaling is applied to subframe, after a subframe receiving the second CSR signaling, the first CSR signaling is applied to subframe , after a subframe receiving a reception acknowledge signal of the first CSR signaling from the UE, N1 and N2 are predefined.

Preferably, the reception acknowledge signal of the first CSR signaling includes:

a given value of a given bit, or a resource index of an initial transmission of the first CSR signaling.

The present disclosure also provides a PMI receiving device, including a transmitting module and a receiving module, wherein

the transmitting module is to transmit first CSR signaling and second CSR signaling, wherein the first CSR signaling indicates an available PMI set of all the PMIs, the second CSR signaling indicates an available PMI set of a UE, on the basis of the first CSR signaling; and

the receiving module is to receive CSI reported by the UE, wherein the CSI includes a PMI obtained by the UE, after referring to the first CSR signaling and the second CSR signaling.

The present disclosure also provides a PMI transmitting method, including:

receiving first CSR signaling, wherein the first CSR signaling indicates an available PMI set of all the PMIs;

receiving second CSR signaling, wherein the second CSR signaling indicates an available PMI set for a UE, on the basis of the first CSR signaling; and,

obtaining a complete CSR based on the first CSR signaling and the second CSR signaling, obtaining a PMI after referring to the complete CSR, and reporting the PMI carried by CSI.

Preferably, the method further includes:

after receiving the first CSR signaling, reporting a reception acknowledge signal of the first CSR signaling.

Preferably, wherein obtaining the complete CSR based on the first CSR signaling and the second CSR signaling, includes:

determining the available PMI set in the first CSR signaling, based on the second CSR signaling; or,

determining a first available PMI in the first CSR signaling, based on the second CSR signaling;

taking the first available PMI and subsequent (N-1) PMIs as available PMIs, wherein a total number N of the available PMIs is predefined; or,

determining a bit offset of a PMI set allowed by the first CSR signaling, based on the second CSR signaling, shifting corresponding bits of the PMI set allowed by the first CSR signaling to the right, based on the bit offset, and obtaining the available PMI set.

Preferably, the method further includes:

applying the second CSR signaling to subframe, after a subframe receiving the second CSR signaling;

applying the first CSR signaling to subframe, after a subframe transmitting a reception acknowledge signal of the first CSR signaling, wherein N1 and N2 are predefined.

Preferably, the reception acknowledge signal of the first CSR signaling is a given value of a given bit, or a resource index of an initial transmission of the first CSR signaling.

The present disclosure also provides a PMI transmitting device, including a receiving module and a measurement reporting module, wherein

the receiving module is to receive first CSR signaling and second CSR signaling, wherein the first CSR signaling indicates an available PMI set of all the PMIs, the second CSR signaling indicates an available PMI set of a UE, on the basis of the first CSR signaling; and,

the measurement reporting module is to report CSI with a PMI, wherein the PMI is obtained by the UE after referring to the first CSR signaling and the second CSR signaling.

Based on foregoing technical solutions, it can be seen that in the PMI transmitting method, the PMI receiving method and corresponding devices provided by the present disclosure, the eNB may divide the CSR into first CSR signaling and second CSR signaling to be issued. After receiving the first CSR signaling and the second CSR signaling, the UE determines an available PMI set, based on the first CSR signaling and the second CSR signaling. And then, the UE determines a PMI in the available PMI set, and feeds back the determined PMI to the eNB.

By using foregoing technical solution of the present disclosure, the following advantages may be achieved.

1) Respectively employ a different transmission frequency (e.g., respectively employ semi-static signaling and dynamic signaling) to issue the first CSR signaling and the second CSR signaling, so as to improve the dynamics for issuing CSR. Subsequently, the CSR may meet higher time-varying interference requirements in the future MIMO system.

2) The PMI feedback is encoded within the available PMI set of the UE, instead of being encoded within an original codebook set, so as to reduce the PMI feedback overhead. Meanwhile, PMI accuracy loss resulted from codebook sub-sampling may be avoided.

3) A user terminal combines the first CSR signaling and the second CSR signaling, so as to implement dynamical CSR. Subsequently, high reconstruction delay resulted from CSR semi-static characteristics may be reduced.

4) By using a reception acknowledge signal of the first CSR signaling, the eNB learns whether the UE selecting the PMI obtains the CSR signaling. Subsequently, ambiguity problem of RRC signaling may be solved.

FIG.1 is a schematic diagram illustrating a cross-polarized 2-D antenna array.

FIG.2 is a schematic diagram illustrating a unipolar 2-D antenna array.

FIG.3 is a flowchart illustrating a PMI receiving method, in accordance with an example of the present disclosure.

FIG.4 is a flowchart illustrating a PMI transmitting method, in accordance with an example of the present disclosure.

FIG.5 is a schematic diagram illustrating structure of a PMI receiving device, in accordance with an example of the present disclosure.

FIG.6 is a schematic diagram illustrating structure of a PMI transmitting device, in accordance with an example of the present disclosure.

To make objectives, technical solutions and advantages of the present disclosure more clear, detailed descriptions of the present disclosure will be provided in the following, accompanying with attached figures and embodiments.

To solve problems in the prior art, the present disclosure provides a PMI receiving method, which may be applied to an eNB side. Firstly, respectively transmit first CSR signaling and second CSR signaling. The first CSR signaling indicates an available PMI set of all the PMIs. On the basis of the first CSR signaling, the second CSR signaling indicates an available PMI set of a UE. And then, receive CSI reported by the UE, which may include as follows. After referring to the first CSR signaling and the second CSR signaling by the UE, the PMI is obtained. The PMI is selected by the UE from the available PMI set of the UE, which is indicated by the second CSR signaling on the basis of the first CSR signaling.

A second frequency for transmitting the second CSR signaling may be greater than, or equal to a first frequency transmitting the first CSR signaling. In addition, after transmitting the first CSR signaling, the method may further include as follows. Receive a reception acknowledge signal of the first CSR signaling from the UE.

After receiving the CSI, schedule users based on prior art. Calculate a precoding vector based on the reported CSI. And then, transmit a downlink assignment (DL grant) in a physical downlink control channel (PDCCH)/an enhanced PDCCH (E-PDCCH). And transmit precoded data in a PDSCH.

Correspondingly, the present disclosure also provides a PMI transmitting method, which is applied to UE side. Firstly, receive the first CSR signaling and the second CSR signaling. The first CSR signaling indicates an available PMI set of all the PMIs. On the basis of the first CSR signaling, the second CSR signaling indicates an available PMI set for a UE. And then, obtain a complete CSR, by using the first CSR signaling and the second CSR signaling. After referring to the complete CSR, obtain the PMI. Finally, report the PMI carried by the CSI.

After obtaining the complete CSR, by referring to the first CSR signaling and the second CSR signaling, the UE selects a PMI from the available PMI set, which is indicated by the complete CSR.

Current PMI feedback is encoded within an original codebook set. For example, when codebook size is 16, 4 bits are needed to transmit the PMI. However, in the present disclosure, after referring to the first CSR signaling and the second CSR signaling by the UE, the obtained available PMI set of the UE is smaller than the original codebook set. Correspondingly, less bits are used to feed back the PMI.

After reporting the CSI, obtain DL grant with PDCCH/E-PDCCH based on prior art. And, receive precoded data signal with PDSCH.

Detailed descriptions about the technical solutions of the present disclosure will be provided in the following, accompanying with several embodiments.

Embodiment 1

FIG.3 is a flowchart illustrating a PMI receiving method, in accordance with an example of the present disclosure, which is applied to eNB side. With reference to FIG.3, the method may include the following blocks.

In block 1, divide a CSR into a first CSR set and a second CSR set, which respectively form first CSR signaling and second CSR signaling. The first CSR signaling indicates an available PMI set of all the PMIs. On the basis of the first CSR signaling, the second CSR signaling indicates an available PMI set of a UE. The second CSR signaling cannot change RI limitations. Besides, a second frequency for transmitting the second CSR signaling is greater than, or equal to a first frequency transmitting the first CSR signaling. That is, the first CSR signaling is to indicate a preliminary available PMI set. On the basis of the first CSR signaling, the second CSR signaling indicates the finally available PMI set.

The first CSR signaling and the second CSR signaling may respectively execute a corresponding indication, by using bitmap bit method. Specifically, there are several methods for the second CSR signaling to indicate an available PMI set, on the basis of the first CSR signaling.

1) The bitmap bit of the second CSR signaling directly indicates an available PMI set, which is in the first CSR signaling.

2) The bitmap bit of the second CSR signaling indicates a first available PMI, which is in the first CSR signaling. The first available PMI and subsequent (N-1) PMIs are available PMIs. The total number N of available PMI is predefined.

3) The bitmap bit of the second CSR signaling indicates a bit offset in a PMI set, which is allowed by the first CSR signaling. For example, suppose bitmap bits of the second CSR signaling is N, after shifting N bits to the right, the PMI allowed by the first CSR signaling becomes the final available PMI set.

In block 2, transmit RRC signaling in PDSCH channel. The RRC signaling includes the first CSR signaling, CQI report configuration, CSI-reference signal (RS) configuration, and so on.

In block 3, transmit DCI in PDCCH. The DCI includes the second CSR signaling.

Based on blocks 2 and 3, in the example, the first CSR signaling is transmitted by RRC signaling under a semi-static mode. The second CSR signaling is transmitted by DCI under a dynamic mode. In this case, by using flexibility of DCI, the second CSR signaling may be changed rapidly, based on CSI change.

In block 4, receive CSI and a reception acknowledge signal of the first CSR signaling, which is reported by the UE. The CSI includes PMI. The PMI is obtained by the UE, after referring to the first CSR signaling and the second CSR signaling.

Specifically, for the mode receiving a reported signal:

in a periodic CSI report, firstly transmit a periodic feedback trigger signal with DCI in PDCCH, and then receive a periodic CSI report with physical uplink shared channel (PUSCH) detection.

Alternatively, in an aperiodic CSI report, receive an aperiodic CSI report with physical uplink control channel (PUCCH) or PUSCH detection.

Since the second CSR signaling is transmitted in PDCCH, it may be considered that the second CSR signaling in such subframe has been received successfully, and then is applied to subframe, after a subframe receiving the second CSR signaling. N1 is predefined. The first CSR signaling is applied to subframe, after a subframe receiving the reception acknowledge signal of the first CSR signaling from the UE. N2 is predefined. There are several formats for the reception acknowledge signal of the first CSR signaling.

The UE reports one bit, which may be taken as the reception acknowledge signal of the first CSR signaling, so as to inform the change of CSR. For example, when the bit is 1, it represents that the first CSR signaling has been received successfully.

Alternatively, the UE may report number of first resource with the first CSR signaling, which may be taken as the reception acknowledge signal of the first CSR signaling. For example, when the first CSR signaling is transmitted with RRC signaling, take number of the first subframe carrying the first CSR signaling as the reception acknowledge signal of the first CSR signaling.

In block 5, schedule users, and calculate a precoding vector based on reported CSI.

In block 6, transmit a DL grant in PDCCH/E-PDCCH, and transmit precoded data in PDSCH.

Embodiment 2

FIG.4 is a flowchart illustrating a PMI transmitting method, in accordance with an example of the present disclosure, which is applied to UE side. With reference to FIG.4, the method includes the following blocks.

In block 1, receive RRC signaling by using PDSCH detection. The RRC signaling includes the first CSR signaling, CQI report configurations, CSI-RS configuration, and so on.

In block 2, obtain DCI by using PDCCH detection, so as to obtain the second CSR signaling.

In block 3, on the basis of the method in block 1 of Embodiment 1, obtain a complete CSR reversely, by using the first CSR signaling and the second CSR signaling. And then, calculate CSI carrying PMI to be reported, based on CSI-RS and CSI-interference measurement (IM).

In block 4, transmit a reception acknowledge signal of the first CSR signaling, and report CSI. The CSI includes PMI, which is obtained after referring to the CSR. Generate the reception acknowledge signal of the first CSR signaling, based on block 4 in Embodiment 1. Specifically, for the mode transmitting a reported signal,

in a periodic CSI report, firstly receive DCI in PDCCH, obtain a periodic feedback trigger signal, and then transmit a periodic CSI report signal in PUSCH, alternatively,

in an aperiodic CSI report, transmit an aperiodic CSI report in PUCCH or PUSCH.

In block 5, obtain a DL grant in PDCCH/E-PDCCH, and receive a precoded data signal in PDSCH.

Embodiment 3

Corresponding to foregoing PMI receiving method, the example provides a PMI receiving device. FIG.5 is a schematic diagram illustrating structure of the PMI receiving device, which includes a transmitting module and a receiving module.

The transmitting module is to transmit first CSR signaling and second CSR signaling. The first CSR signaling indicates an available PMI set of all the PMIs. The second CSR signaling indicates an available PMI set for a UE, on the basis of the first CSR signaling.

The receiving module is to receive CSI reported by the UE. The CSI includes a PMI obtained by the UE, after referring to the first CSR signaling and the second CSR signaling.

The PMI receiving device in FIG.5 may further include a scheduling module and a precoding module.

The scheduling module is to perform scheduling, and to calculate a precoding vector based on PMI reported by the UE.

The precoding module is to transmit a DL grant in PDCCH/E-PDCCH, and transmit precoded data in PDSCH.

Embodiment 4

Corresponding to foregoing PMI transmitting method, the example provides a PMI transmitting device. FIG.6 is a schematic diagram illustrating structure of the PMI transmitting device, which includes a receiving module and a measurement reporting module.

The receiving module is to receive first CSR signaling and second CSR signaling. The first CSR signaling indicates an available PMI set of all the PMIs. The second CSR signaling indicates an available PMI set of a UE, on the basis of the first CSR signaling.

The measurement reporting module is to report CSI carrying PMI. The PMI is obtained by the UE, after referring to the first CSR signaling and the second CSR signaling.

The foregoing is preferred embodiments of the present disclosure, which is not used for limiting the present disclosure. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present disclosure, should be covered by the protection scope of the present disclosure.

Claims

A precoding matrix indicator (PMI) receiving method, comprising:

transmitting first codebook subset restriction (CSR) signaling, wherein the first CSR signaling indicates an available PMI set of all the PMIs;

transmitting second CSR signaling, wherein the second CSR signaling indicates an available PMI set for a user equipment (UE), on the basis of the first CSR signaling; and,

receiving channel state information (CSI) reported by the UE, wherein the CSI comprises a PMI obtained by the UE, after referring to the first CSR signaling and the second CSR signaling.
The method according to claim 1, wherein a second frequency transmitting the second CSR signaling is greater than, or equal to a first frequency transmitting the first CSR signaling.
The method according to claim 1 or 2, further comprising:

after transmitting the first CSR signaling, receiving a reception acknowledge signal of the first CSR signaling from the UE.
The method according to claim 1 or 2, wherein the second CSR signaling indicates the available PMI set for the UE, on the basis of the first CSR signaling, comprises:

indicating, by the second CSR signaling, the available PMI set in the first CSR signaling; or,

indicating, by the second CSR signaling, a first available PMI in the first CSR signaling, wherein the first available PMI and subsequent (N-1) PMIs are available PMIs, a total number N of the available PMIs is predefined; or,

indicating, by the second CSR signaling, a bit offset of a PMI set allowed by the first CSR signaling.
The method according to claim 1 or 2, wherein the second CSR signaling is applied to subframe, after a subframe receiving the second CSR signaling, the first CSR signaling is applied to subframe , after a subframe receiving a reception acknowledge signal of the first CSR signaling from the UE, N1 and N2 are predefined.
The method according to claim 1 or 2, wherein the reception acknowledge signal of the first CSR signaling comprises:

a given value of a given bit, or a resource index of an initial transmission of the first CSR signaling.
A precoding matrix indicator (PMI) receiving device, comprising a transmitting module and a receiving module, wherein

the transmitting module is to transmit first codebook subset restriction (CSR) signaling and second CSR signaling, wherein the first CSR signaling indicates an available PMI set of all the PMIs, the second CSR signaling indicates an available PMI set of a user equipment (UE), on the basis of the first CSR signaling; and

the receiving module is to receive channel state information (CSI) reported by the UE, wherein the CSI comprises a PMI obtained by the UE, after referring to the first CSR signaling and the second CSR signaling.
A precoding matrix indicator (PMI) transmitting method, comprising:

receiving first codebook subset restriction (CSR) signaling, wherein the first CSR signaling indicates an available PMI set of all the PMIs;

receiving second CSR signaling, wherein the second CSR signaling indicates an available PMI set for a user equipment (UE), on the basis of the first CSR signaling; and,

obtaining a complete CSR based on the first CSR signaling and the second CSR signaling, obtaining a PMI after referring to the complete CSR, and reporting the PMI carried by channel state information (CSI).
The method according to claim 8, wherein a second frequency transmitting the second CSR signaling is greater than, or equal to a first frequency transmitting the first CSR signaling.
The method according to claim 8 or 9, further comprising:

after receiving the first CSR signaling, reporting a reception acknowledge signal of the first CSR signaling.
The method according to claim 8 or 9, wherein obtaining the complete CSR based on the first CSR signaling and the second CSR signaling, comprises:

determining the available PMI set in the first CSR signaling, based on the second CSR signaling; or,

determining a first available PMI in the first CSR signaling, based on the second CSR signaling;

taking the first available PMI and subsequent (N-1) PMIs as available PMIs, wherein a total number N of the available PMIs is predefined; or,

determining a bit offset of a PMI set allowed by the first CSR signaling, based on the second CSR signaling, shifting corresponding bits of the PMI set allowed by the first CSR signaling to the right, based on the bit offset, and obtaining the available PMI set.
The method according to claim 8 or 9, further comprising:

applying the second CSR signaling to subframe, after a subframe receiving the second CSR signaling;

applying the first CSR signaling to subframe, after a subframe transmitting a reception acknowledge signal of the first CSR signaling, wherein N1 and N2 are predefined.
The method according to claim 10, wherein the reception acknowledge signal of the first CSR signaling is a given value of a given bit, or a resource index of an initial transmission of the first CSR signaling.
A precoding matrix indicator (PMI) transmitting device, comprising a receiving module and a measurement reporting module, wherein

the receiving module is to receive first codebook subset restriction (CSR) signaling and second CSR signaling, wherein the first CSR signaling indicates an available PMI set of all the PMIs, the second CSR signaling indicates an available PMI set of a user equipment (UE), on the basis of the first CSR signaling; and,

the measurement reporting module is to report channel state information (CSI) with a PMI, wherein the PMI is obtained by the UE after referring to the first CSR signaling and the second CSR signaling.