CN109617581B

CN109617581B - Method, apparatus and computer readable medium for channel state information feedback

Info

Publication number: CN109617581B
Application number: CN201710925753.7A
Authority: CN
Inventors: 刘皓
Original assignee: Nokia Shanghai Bell Co Ltd; Nokia Networks Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Oyj
Priority date: 2017-10-05
Filing date: 2017-10-05
Publication date: 2020-10-09
Anticipated expiration: 2037-10-05
Also published as: CN109617581A

Abstract

Implementations of the present disclosure provide methods, apparatuses, and computer-readable media for Channel State Information (CSI) feedback. According to implementations of the present disclosure, in determining CSI feedback, a terminal device determines an indication of a match to channel conditions between a network device and the terminal device, regardless of uplink resources that have been allocated for transmission of the CSI feedback. Furthermore, the terminal device determines, based on the indication, that another indication can be determined by the allocated uplink resource bearer and determines precoding information based on the other indication. And the terminal equipment transmits CSI feedback comprising the two indications and precoding information to the network equipment. In this way, the network device can not only normally receive precoding information in CSI feedback, but also allocate uplink resources more suitable for transmission of subsequent CSI feedback to the terminal device based on the indication matching with the channel condition.

Description

Method, apparatus and computer readable medium for channel state information feedback

Technical Field

Implementations of the present disclosure relate generally to communication technology and, more particularly, relate to a method, apparatus, and computer-readable medium for channel state information feedback.

Background

In recent communication developments, New Radio (NR) access technologies are being researched, which aim to provide a wider range of vertical communication services such as Machine Type Communication (MTC), large-scale MTC (MTC), enhanced mobile broadband (eMBB) communication, ultra-reliable low-delay communication (URLLC), and the like, in a single technology framework. In NR access technologies, some communication procedures and/or information need to be redesigned or adjusted in order to meet higher communication requirements.

Typically, the terminal device feeds back Channel State Information (CSI) to the network device. The network device may determine some parameters to employ for downlink transmission based on the CSI feedback. In the Long Term Evolution (LTE) specification, CSI feedback may include related information such as Rank Indication (RI), Channel Quality Indication (CQI), and Precoding Matrix Indication (PMI). This information is a factor that the terminal device proposes to the network device to consider in the downlink transmission process based on the measured channel conditions. In NR techniques, the information contained in the CSI feedback and the transmission of the CSI feedback may need to be redesigned.

Disclosure of Invention

In accordance with example implementations of the present disclosure, methods, apparatuses, and computer-readable media for Channel State Information (CSI) feedback are provided.

In a first aspect of the disclosure, a method implemented at a terminal device is provided. The method includes determining a first indication of Channel State Information (CSI) feedback based on a channel condition between the network device and the terminal device, the first indication matching the channel condition. The method also includes generating a second indication of CSI feedback by modifying the first indication based on the uplink resources allocated for transmission of the CSI feedback, and generating precoding information for the CSI feedback based on the second indication. The size of the payload of the precoding information depends on the second indication. The method further includes transmitting CSI feedback to the network device using the uplink resource, the CSI feedback including the first indication, the second indication, and the precoding information.

In a second aspect of the disclosure, a method implemented at a network device is provided. The method includes receiving, from a terminal device, a first indication and a second indication of Channel State Information (CSI) feedback on a first portion of uplink resources that have been allocated for transmission of the CSI feedback. The first indication matches a channel condition between the network device and the terminal device, and the second indication is generated by modifying the first indication based on the uplink resources. The method also includes receiving precoding information for CSI feedback from the terminal device on a second portion of the uplink resources based on the second indication. The size of the payload of the precoding information depends on the second indication.

In a third aspect of the present disclosure, a terminal device is provided. The terminal device includes a processor; and a memory coupled with the processor, the memory having instructions stored therein that, when executed by the processor, cause the terminal device to perform actions. The actions include: a first indication of Channel State Information (CSI) feedback is determined based on a channel condition between the network device and the terminal device, the first indication matching the channel condition. The actions further include generating a second indication of CSI feedback by modifying the first indication based on the uplink resources allocated for transmission of the CSI feedback, and generating precoding information for the CSI feedback based on the second indication. The size of the payload of the precoding information depends on the second indication. The actions further include transmitting CSI feedback to the network device using the uplink resource, the CSI feedback comprising the first indication, the second indication, and the precoding information.

In a fourth aspect of the disclosure, a network device is provided. The terminal device includes a processor; and a memory coupled with the processor, the memory having instructions stored therein that, when executed by the processor, cause the network device to perform actions. The actions include: first and second indications of Channel State Information (CSI) feedback are received from a terminal device on a first portion of uplink resources that have been allocated for transmission of the CSI feedback. The first indication matches a channel condition between the network device and the terminal device, and the second indication is generated by modifying the first indication based on the uplink resources. The actions further include receiving precoding information for CSI feedback from the terminal device on a second portion of the uplink resources based on the second indication. The size of the payload of the precoding information depends on the second indication.

In a fifth aspect of the disclosure, a computer-readable medium is provided. The computer-readable medium has stored thereon computer-executable instructions. The computer-executable instructions, when executed by one or more processors, cause the one or more processors to perform the steps of the method according to the first aspect.

In a sixth aspect of the disclosure, a computer-readable medium is provided. The computer-readable medium has stored thereon computer-executable instructions. The computer-executable instructions, when executed by one or more processors, cause the one or more processors to perform the steps of the method according to the second aspect.

It should be understood that what is described in this summary section is not intended to limit key or critical features of the disclosure, nor is it intended to limit the scope of the disclosure. Other features of the present disclosure will become apparent from the following description.

Drawings

The above and other features, advantages and aspects of various implementations of the present disclosure will become more apparent by referring to the following detailed description when taken in conjunction with the accompanying drawings. In the drawings, like or similar reference characters designate like or similar elements, and wherein:

FIG. 1 is a schematic diagram of an example network environment in which implementations described in this disclosure may be implemented;

fig. 2 illustrates an example structure of type II CSI in accordance with some implementations of the present disclosure;

fig. 3 illustrates a flow diagram of a process for CSI feedback at a terminal device in accordance with some implementations of the present disclosure;

fig. 4 is a flow diagram of a process for CSI feedback at a network device in accordance with some implementations of the present disclosure;

fig. 5 is an interaction diagram for CSI feedback between a terminal device and a network device in accordance with some implementations of the present disclosure; and

fig. 6 illustrates a simplified block diagram of a device suitable for implementing implementations of the present disclosure.

Throughout the drawings, the same or similar reference numbers refer to the same or similar elements.

Detailed description of the invention

Implementations of the present disclosure will be described in more detail below with reference to the accompanying drawings. While certain implementations of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be construed as limited to the implementations set forth herein, but rather are provided for a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and implementations of the present disclosure are for illustration purposes only and are not intended to limit the scope of the present disclosure.

In the description of implementations of the present disclosure, the terms "include" and "comprise," and similar terms, are to be understood as being open-ended, i.e., "including but not limited to. The term "based on" should be understood as "based at least in part on". The term "one implementation" or "the implementation" should be understood as "at least one implementation". The terms "first," "second," and the like may refer to different or the same object. Other explicit and implicit definitions are also possible below.

The term "terminal equipment" or "user equipment" (UE) as used herein refers to any terminal equipment capable of wireless communication with a base station or with each other. As an example, the terminal device may include a Mobile Terminal (MT), a Subscriber Station (SS), a Portable Subscriber Station (PSS), a Mobile Station (MS) or an Access Terminal (AT), various Machine Type Communication (MTC) terminals, and the above-described devices mounted in a vehicle. The terminal device may be any type of mobile terminal, fixed terminal, or portable terminal including a mobile handset, station, unit, device, multimedia computer, multimedia tablet, internet node, communicator, desktop computer, laptop computer, notebook computer, netbook computer, tablet computer, Personal Communication System (PCS) device, personal navigation device, Personal Digital Assistant (PDA), audio/video player, digital camera/camcorder, positioning device, television receiver, radio broadcast receiver, electronic book device, game device, smart meter, or other device that may be used for communication, or any combination of the above. In the context of the present disclosure, the terms "terminal device" and "user equipment" may be used interchangeably for purposes of discussion convenience.

The term "network device" as used herein refers to a base station or other entity or node having a particular function in a communication network. A "base station" (BS) may represent a node B (NodeB or NB), an evolved node B (eNodeB or eNB), a Remote Radio Unit (RRU), a Radio Head (RH), a Remote Radio Head (RRH), a relay, or a low power node such as a pico base station, a femto base station, or the like. The coverage area of a base station, i.e. the geographical area where it is able to provide service, is called a cell. In the context of the present disclosure, the terms "network device" and "base station" may be used interchangeably for ease of discussion purposes, and may primarily be used with the EnBW as an example of a network device.

FIG. 1 depicts a network environment 100 in which implementations of the present disclosure may be implemented. In this environment 100, a terminal device 120 is in a serving cell 112 of a network device 110 and is served by the network device 110. Although terminal devices in the form of mobile phones are shown in fig. 1, network device 110 may serve more or fewer terminal devices, and the types of terminal devices served may be the same or different (e.g., other types of terminal devices are also possible).

The network device 110 and the terminal device 120 may communicate with each other to transmit various service data, control information, and the like. The transmitting end may be network device 110 and the receiving end may be one or more terminal devices 120, and such transmissions may be referred to as Downlink (DL) transmissions. In other cases, the transmitting end may be terminal device 120 and the receiving end may be network device 110, and such transmissions may be referred to as Uplink (UL) transmissions.

Communications in network environment 100 may be implemented in accordance with any suitable communication protocol, including, but not limited to, first-generation (1G), second-generation (2G), third-generation (3G), fourth-generation (4G), and fifth-generation (5G) cellular communication protocols, wireless local area network communication protocols such as Institute of Electrical and Electronics Engineers (IEEE)802.11, and/or any other protocol now known or later developed.

As mentioned above, the terminal device may transmit CSI feedback to the network device for the network device to consider in determining parameters for downlink transmission. In conventional CSI feedback, the size of the CSI feedback is specified, and thus the network device may allocate a specified uplink resource for the terminal device for CSI feedback. Currently, in NR technology, a new type of CSI feedback, i.e., type II CSI feedback, has been proposed. This new type of CSI feedback carries more detailed information than conventional CSI feedback. Thus, the payload of such CSI feedback is larger and the size may also vary with the channel conditions between the network device and the terminal device. An example type II CSI feedback includes information and its payload size is described below.

In one example, type II CSI feedback is based on a two-stage precoding codebook structure, with rank 2 highest. Such a two-stage codebook is denoted as W1x W2. The first stage W1 includes, for example, a set of orthogonal beams (e.g., L orthogonal beams) chosen from oversampled two-dimensional (2D) Discrete Fourier Transform (DFT) beams predefined for a single polarization direction. The second stage W2 includes (2L-1) beam combining coefficients for L orthogonal beams and two polarization directions in each antenna layer (or simply "layer"). In general, the beam combining coefficients may be divided into separate quantization of the phase combining coefficients and quantization of the amplitude combining coefficients. The phase combining coefficients are configured for Subband (SB) reporting, while the amplitude combining coefficients include Wideband (WB) amplitude and SB differential amplitude (if configured).

For such a fine codebook, type II CSI feedback from the terminal device may be able to indicate a two-stage codebook. Generally, CSI feedback includes Rank Indication (RI), Channel Quality Indication (CQI), and Precoding Matrix Indication (PMI). For new type II CSI feedback, the division of type II CSI feedback into two pieces of information, which are transmitted separately, has been discussed and agreed. Fig. 2 shows an example structure of a type II CSI feedback 200. As shown, the type II CSI feedback 200 includes a first partial information 201 and a second partial information 202. The first part of information 201 includes indications such as Rank Indication (RI), Channel Quality Indication (CQI), and number of non-zero wideband amplitude coefficients for each antenna layer. The second part of information 202 includes the remaining information, such as precoding information, and may specifically include the selection of orthogonal beams, WB amplitude coefficients for each antenna layer and an indication of the strongest coefficients therein, SB phase combining and SB differential amplitude for each antenna layer (if configured).

The payload size of the first part of information 201 is typically fixed. The maximum number of layers of the codebook is related to the number of bits for reporting the RI. If the maximum number of layers is 2, the RI only occupies 1 bit. The number of bits of the CQI also relates to the total number of available CQIs defined. For example, in the NR technique, when RI is not greater than 4, a single codeword is configured, and thus the type II CSI feedback codebook requires only a single CQI, and thus is also a fixed number of bits. If the LTE criteria are reused in NR techniques, the CQI includes a WB CQI and a set of SB CQIs. The value of WB CQI is represented as 4-bit CQI quantization, the value of SB CQI is at each subbandIn the above, differential coding with respect to WB CQI is achieved using 2 bits. Here, the number of non-zero WB amplitudes includes two indications of coefficients for each antenna layer. Assuming that L orthogonal beams are selected for the type II CSI feedback codebook, then each antenna layer has 2L WB amplitude coefficients. The total number of bits required for reporting the number of non-zero WB amplitude coefficients can be expressed as

(for two antenna layers). Therefore, according to the above example, the payload size of each part of the first part information 201 and the variation of the total payload size with the number of beams L are summarized in the following table 1. It can be seen that the payload size of the first part of information 201 is between 29 and 31 bits and is fixed for a particular number of beams (L), regardless of the value of RI.

Table 1: example payload size of the first portion of information

The payload size of the second part of information 202 is related to the defined precoding codebook and depends on the first part of information 201, in particular on the RI therein and the number of non-zero WB amplitude coefficients per antenna layer. For example, compared to RI 2, in the case of RI 1, the payload of the second partial information 202 is reduced by about half because of the reduction in the number of antenna layers. When a WB magnitude of 2L coefficients is quantized to zero for a layer, the SB phase-combining coefficients, or even the SB differential magnitudes (if configured), corresponding to that layer need not be reported, which also reduces the payload size of the second part of information 202. An example calculation of the respective information payload sizes and total payload of the second portion of information 202 from the above two-level codebook is given in table 2 below. In the example of table 2, assume that RI is 1, the number of orthogonal beams selected is L, and the number of non-zero WB amplitude coefficients is N. It can be seen that the payload of the second part of information 202 varies with the number of non-zero WB amplitude coefficients for a particular RI and number of orthogonal beams L. Note that the number of orthogonal beams L is a long-term configuration parameter, and is usually a fixed value for a long time, so that the payload size of the second part of information is not dynamically affected.

Table 2: example payload size of the second portion of information

Since the payload size of the second part of information 202 varies depending on the specific value of the first part of information 201, this means that the overall size of the CSI feedback is variable. This presents challenges for the determination of CSI feedback at the terminal device and resource allocation at the network device.

During the discussion of NR techniques, it is proposed that type II CSI feedback may be transmitted on different uplink channels with different transmission periods. For example, CSI feedback may be configured to be transmitted on a long Physical Uplink Control Channel (PUCCH) and a Physical Uplink Shared Channel (PUSCH). The first partial information of the CSI feedback may be transmitted with a longer period on the PUCCH, while the first partial information and the second partial information may also be transmitted with a shorter period on the PUSCH. The network device may determine a payload size of the second partial information based on the first partial information received on the PUCCH and accordingly allocate resources of the PUSCH for transmission of CSI feedback. However, the first partial information transmitted on the PUCCH and the PUSCH are both determined by the terminal device based on the channel condition between the network device and the terminal device, and the transmission cycle of the PUCCH is long. This means that the resource allocation determined based on the first partial information on PUCCH may not match the overall CSI feedback transmitted on PUSCH.

In another scheme, only the PUSCH is configured for transmitting CSI feedback. In this case, if the size of information that the allocated resources of the PUSCH can transmit is larger than the payload size of the CSI feedback to be transmitted. Upon receiving CSI feedback transmitted using the current resource, the network device may determine that the previously allocated resource is not fully utilized, thus correspondingly reducing the PUSCH resources to be subsequently allocated such that the reduced PUSCH resources match the overall size of the currently received CSI feedback. Conversely, if the allocated resources are more or less fully used for transmission of CSI feedback, the network device will not adjust the resource allocation. However, if the channel condition between the network device and the terminal device changes, the payload size of the CSI feedback matching the channel condition is larger than the size of information that can be transmitted by the allocated resources. In order to be able to transmit CSI feedback on the allocated resources, the terminal device will adjust the matched CSI feedback such that the payload size of the second part of information is reduced. In this case, the network device will not know whether the received CSI feedback is a feedback matching the current channel conditions or a feedback that the terminal device adjusted to adapt to the resource allocation, and thus also cannot adjust the resource allocation for PUSCH accordingly.

In accordance with implementations of the present disclosure, a scheme for CSI feedback is provided. In this scheme, in determining CSI feedback, the terminal device determines an indication of a match to channel conditions between the network device and the terminal device, regardless of the uplink resources that have been allocated for transmission of the CSI feedback. Furthermore, the terminal device determines, based on the indication, that another indication can be determined by the allocated uplink resource bearer and determines precoding information based on the other indication. And the terminal equipment transmits CSI feedback comprising the two indications and precoding information to the network equipment. In this way, the network device can not only normally receive precoding information in CSI feedback, but also allocate uplink resources more suitable for transmission of subsequent CSI feedback to the terminal device based on the indication matching with the channel condition. Such CSI feedback is particularly suitable for schemes where only one uplink channel (e.g., PUSCH) is configured for transmission of CSI feedback.

Implementations of the present disclosure will be described in detail below with reference to the accompanying drawings. Fig. 3 illustrates a flow diagram of a process 300 for CSI feedback in accordance with some implementations of the present disclosure. For purposes of discussion, the process 300 will be described with reference to fig. 1. It is to be appreciated that process 300 may be implemented, for example, at terminal device 120 as shown in fig. 1. Implementations of the present disclosure are suitable for CSI feedback, in particular type II CSI feedback, comprising two-part information. The payload size of one part of information in the feedback is determined by the specific value of the other part of information.

At 310, terminal device 120 determines a first indication of CSI feedback based on a channel condition between network device 110 and terminal device 120, the first indication matching the channel condition. According to implementations of the present disclosure, an indication matching the channel condition is always included in the CSI feedback, rather than a modified indication according to the allocated uplink resources. In the example of type IICSI feedback 200 shown in fig. 2, the first indication may comprise one or more indications in the first part of information 201, in particular an indication deciding the payload size of the second part of information 202 of the CSI feedback. For example, the first indication may include at least one of RI and the number of non-zero WB amplitude coefficients for each antenna layer.

In implementations of the present disclosure, the first indication "matches the channel condition" means that the value of the first indication is an indication selected by the terminal device 120 as being suitable for use under the channel condition.

In some implementations, terminal device 120 may evaluate channel conditions with reference signals. For example, network device 110 may send a reference signal to terminal device 120 before determining CSI feedback. Terminal device 120 evaluates the current channel conditions based on the received reference signals. Such reference signals may be, for example, channel state indication-reference signals (CSI-RS), or any other type of reference signal.

At 315, the terminal device 120 generates a second indication of CSI feedback by modifying the first indication based on the uplink resources that have been allocated for transmission of CSI feedback. In implementations of the present disclosure, as mentioned above, the payload size of the second part of information (i.e., precoding information) in the CSI feedback depends on the second indication of the CSI feedback. The precoding information determined directly based on the first indication matching the channel condition may have too high a payload to be carried by the allocated uplink resources. Thus, the terminal device 120 also modifies the first indication taking into account the allocated uplink resources to generate the second indication.

In particular, the generation of the second indication takes into account the bearer capability of the allocated uplink resources. In some implementations, the second indication is generated in a manner such that a payload of precoding information generated based on the second indication can be carried by a portion of the allocated uplink resources. As mentioned above, the indication in the CSI feedback typically has a fixed payload size, so the first indication and the second indication generated modified by the first indication have a fixed payload size. Network device 110 may always allocate uplink resources capable of carrying the portion of the fixed payload size when allocating uplink resources. However, the payload of the precoding information is variable, and the allocated uplink resources may not be sufficient to carry the precoding information determined based on the first indication matching the channel condition, except for a part of the resources used to carry the first and second indications. In this case, the terminal device 120 will modify the first indication, e.g., reduce the number of RI (e.g., from RI-2 to RI-1) and/or non-zero WB magnitude coefficients, such that the payload size of the corresponding precoding information is reduced to a level that can be carried by the uplink resources. That is, the generation of the second indication will make the allocated uplink resources available for transmission of the first indication, the second indication and the precoding information determined by the second indication.

In some implementations, the uplink resources that terminal device 120 can use are allocated by network device 110 for transmission of CSI feedback. The CSI feedback may be configured to be transmitted on the PUSCH, and thus the uplink resources allocated by the network device 110 include resources on the PUSCH. In some implementations, the network device 110 configures only the PUSCH for CSI feedback. In such an implementation, the periodicity of CSI feedback is thus the same as the occurrence periodicity of PUSCH.

In some implementations, the second indication may include other information unrelated to the payload size in addition to the indication related to the size of the payload of the precoding information, such information may not be included in the first indication and may have a fixed payload size. The scope of the present disclosure is not limited in this respect.

At 320, the terminal device 120 generates precoding information for the CSI feedback based on the second indication. In the generation of precoding information, the number of RI and non-zero WB amplitude coefficients in the second indication (instead of the first indication) is used. The precoding information may include such things as the selection of orthogonal beams, WB amplitude coefficients for each antenna layer and an indication of the strongest coefficients among them, SB phase combining and SB differential amplitude for each antenna layer (if configured). These precoding information may refer to the examples discussed above with respect to fig. 2. The network device 110 may refer to this information when selecting relevant parameters for the precoding process.

At 325, terminal device 120 transmits CSI feedback to network device 110 using the allocated uplink resources, the CSI feedback comprising the first indication, the second indication, and the precoding information. Since the first and second indications each have a fixed payload size, these indications will occupy fixed uplink resources. The precoding information generated based on the second indication will occupy the remaining uplink resources. In some implementations, the CSI feedback may additionally include other information, such as CQI. Terminal device 120 may determine the CQI based on the current channel conditions. The payload size of the CQI is also fixed.

Network device 110 receives CSI feedback from terminal device 120 on the corresponding uplink resources. Fig. 4 illustrates a flow diagram showing a process 400 for CSI feedback according to some implementations of the present disclosure. For purposes of discussion, the process 400 will be described with reference to fig. 1. It is to be appreciated that process 400 may be implemented, for example, at network device 110 as shown in fig. 1.

At 410, network device 110 receives a first indication and a second indication from terminal device 120 on a first portion of uplink resources that have been allocated for transmission of CSI feedback. The first portion of uplink resources is of an amount capable of carrying first and second indications of a fixed payload size. At 415, network device 110 receives precoding information for CSI feedback from terminal device 120 on a second portion of the uplink resources based on the second indication. The second indication may indicate the payload size of the precoding information to network device 110 so that network device 110 may determine where the reception of the precoding information ends.

In some implementations, network device 110 may allocate uplink resources for transmission of CSI feedback for terminal device 120 based on the first indication. Because the first indication matches the channel condition, the first indication may be used as a factor by network device 110 in adjusting the resource allocation. The second indication may be adjusted to adapt to a previous resource allocation scenario, which may not actually reflect channel conditions, and thus network device 110 may not consider the second indication when allocating resources for CSI feedback.

In particular, network device 110, when allocating uplink resources for transmission of CSI feedback, allocates the uplink resources as being capable of carrying a payload of precoding information expected to be generated by terminal device 120 based on the first indication. In particular, since the payload size of the precoding information in the CSI feedback varies while the payload size of the first indication and the second indication is fixed, network device 110 may allocate the portion of the uplink resources for transmission of the precoding information in the subsequent CSI feedback based on the first indication without re-allocating the fixed uplink resources for transmission of the first and second indications in the CSI feedback. For example, if the number of RI and non-zero WB amplitude coefficients per antenna layer is larger in the first indication compared to the second indication, this means that the previously allocated uplink resources are not sufficient to carry CSI feedback matching the actual channel conditions. In this case, network device 110 may increase the uplink resources for transmission of CSI feedback according to the system resource allocation. Of course, if the first indication indicates that the uplink transmission resources are substantially sufficient or redundant, the network device 110 may not adjust the resource allocation for CSI feedback or reduce the resources to be allocated.

Network device 110 sends to terminal device 120 resource allocation information relating to uplink resources for subsequent CSI feedback, in particular the portion of the uplink resources for transmission of precoding information in the uplink resources for CSI feedback. As discussed above, the uplink resource is determined based on the reported first indication and is capable of carrying a payload of precoding information expected to be determined by the terminal device 120 based on the first indication. Network device 110 may transmit the resource allocation information to terminal device 120 in a downlink control channel. In some implementations, the network device 110 also transmits a trigger for CSI feedback in the downlink control channel. For fixed uplink resources allocated for transmission of the first and second indications, network device 110 may transmit to terminal device 120 through higher layer signaling. The period of the higher layer signaling is much longer than that of the downlink control channel. This may save signaling overhead between network device 110 and terminal device 120.

Terminal device 120 receives the resource allocation information sent by network device 110. The terminal device 120 may be triggered to transmit the CSI feedback using the uplink resources indicated in the resource allocation information (or the part of the uplink resources indicated in the resource allocation information for the transmission of precoding information together with another part of the uplink resources transmitted in higher layer signaling for the transmission of the first and second indications). The transmission of the CSI feedback by the terminal device 120 may be initiated by a CSI feedback trigger included in the downlink control channel. In the implementation of the present disclosure, since the CSI feedback includes not only the indication corresponding to the payload of the precoding information that can be transmitted, but also the indication that the terminal device 120 actually expects to select based on the channel condition, the network device 110 can not only correctly receive the precoding information of the current CSI feedback, but also timely adjust the uplink resource allocation for the next CSI feedback. In this way, the resource allocation and payload size of the CSI feedback may be flexibly adapted to changes in channel conditions.

The procedures on the terminal device 120 and network device 110 sides are described above in connection with fig. 3 and 4, respectively. For clarity of illustration of the interaction between terminal device 120 and network device 110, fig. 5 illustrates an interaction process 500 that incorporates the two-end devices of fig. 3 and 4 above. The interaction process 500 includes process 300 at terminal device 120 shown in fig. 3, where terminal device 120 shows various pieces of information for CSI feedback at 310 through 320, and sends the CSI feedback to network device 110 at 325. Interaction process 500 also includes process 400 at network device 110 shown in fig. 4, where network device 110 receives various pieces of information for CSI feedback at 410 and 415.

Further, as discussed above, in some example implementations, network device 110 may determine, at 510, resource allocation information for terminal device 120 based on the first indication in the received CSI feedback. At 515, network device 110 transmits the determined resource allocation information to terminal device 120.

Fig. 6 illustrates a simplified block diagram of a device 600 suitable for implementing implementations of the present disclosure. Device 600 may be used to implement, for example, network device 110 or terminal device 120 shown in fig. 1. As shown, device 600 includes one or more processors 610, one or more memories 620 coupled to processor(s) 610, one or more transmitters and/or receivers (TX/RX)640 coupled to processor 610.

The processor 610 may be of any type suitable to the local technical environment, and may include one or more of the following as non-limiting examples: general purpose computers, special purpose computers, microprocessors, Digital Signal Processors (DSPs) and processors based on a multi-core processor architecture. Device 600 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time with a clock synchronized to the main processor.

The memory 620 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as non-transitory computer-readable storage media, semiconductor-based storage devices, magnetic storage devices and systems, optical storage devices and systems, fixed memory and removable memory, as non-limiting examples.

Memory 620 stores at least a portion of program 630. TX/RX 640 is used for bi-directional communication. TX/RX 640 has at least one antenna for facilitating communication. A communication interface may represent any interface necessary to communicate with other devices.

The programs 630 are assumed to include program instructions that, when executed by the associated processor 610, cause the device 600 to perform implementations of the present disclosure as discussed above with reference to fig. 3-5. That is, implementations of the present disclosure may be implemented by computer software executable by the processor 610 of the device 600, or by a combination of software and hardware.

The units or modules described herein may be implemented in a variety of ways including software, hardware, firmware, or any combination thereof. In one implementation, one or more of the units may be implemented using software and/or firmware, such as computer-executable instructions stored on a storage medium. In addition to, or in the alternative to, computer-executable instructions, some or all of the elements described may be implemented, at least in part, by one or more hardware logic components. By way of example, and not limitation, exemplary types of hardware logic components that may be used include Field Programmable Gate Arrays (FPGAs), Application Specific Integrated Circuits (ASICs), Application Specific Standards (ASSPs), systems on a chip (SOCs), Complex Programmable Logic Devices (CPLDs), and so forth.

The units described herein may be implemented partially or wholly as hardware modules, software modules, firmware modules, or any combination thereof. In particular, in some implementations, the above-described flows, methods or processes may be implemented by hardware in a communication device. For example, a communication device may implement the above-described processes with its transmitter, receiver, transceiver, and/or processor or controller.

In general, various example implementations of the disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Certain aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. For example, in some implementations, various examples of the disclosure (e.g., a method, apparatus, or device) may be partially or fully implemented on a computer-readable medium. While various aspects of the implementations of the disclosure may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that the blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

By way of example, implementations of the disclosure may be described in the context of computer-executable instructions, such as program modules, being included in a device executing on a physical or virtual processor of a target. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. In various implementations, the functionality of the program modules may be combined or divided among the program modules described. Computer-executable instructions for program modules may be executed within local or distributed devices. In a distributed facility, program modules may be located in both local and remote memory storage media.

Computer program code for implementing the methods of the present disclosure may be written in one or more programming languages. These computer program codes may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the computer or other programmable data processing apparatus, cause the functions/acts specified in the flowchart and/or block diagram block or blocks to be performed. The program code may execute entirely on the computer, partly on the computer, as a stand-alone software package, partly on the computer and partly on a remote computer or entirely on the remote computer or server.

In the context of this disclosure, a computer readable medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The computer readable medium may be a machine readable signal medium or a machine readable storage medium. A computer readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination thereof. More detailed examples of a machine-readable storage medium include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical storage device, a magnetic storage device, or any suitable combination thereof.

Additionally, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In some cases, multitasking or parallel processing may be beneficial. Likewise, while the above discussion contains certain specific implementation details, this should not be construed as limiting the scope of any invention or claims, but rather as a description of specific implementations that may be directed to a particular invention. Certain features that are described in this specification in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination.

Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A method implemented at a terminal device, comprising:

determining a first indication of Channel State Information (CSI) feedback based on a channel condition between a network device and the terminal device, the first indication matching the channel condition;

generating a second indication of the CSI feedback by modifying the first indication based on uplink resources already allocated for transmission of the CSI feedback;

generating precoding information for the CSI feedback based on the second indication, a size of a payload of the precoding information depending on the second indication; and

transmitting the CSI feedback to the network device using the uplink resource, the CSI feedback including the first indication, the second indication, and the precoding information.

2. The method of claim 1, wherein the uplink resources comprise resources on a Physical Uplink Shared Channel (PUSCH).

3. The method of claim 1, wherein generating the second indication comprises:

generating the second indication in a manner that enables the payload of the precoding information generated based on the second indication to be carried by a portion of the uplink resources.

4. The method of claim 1, further comprising:

after transmitting the CSI feedback, receiving resource allocation information from the network device, the resource allocation information relating to a portion of a second uplink resource for transmission of a second CSI feedback, the portion of the second uplink resource determined based on the first indication and capable of carrying a payload of second precoding information, the payload of the second precoding information intended to be determined by the terminal device based on the first indication.

5. The method of claim 1, wherein the CSI feedback is type ii CSI feedback, wherein the first indication comprises at least one of a Rank Indication (RI) matching the channel condition and a number of non-zero wideband amplitude coefficients per antenna layer.

6. A method implemented at a network device, comprising:

receiving, from a terminal device, a first indication and a second indication of Channel State Information (CSI) feedback on a first portion of uplink resources that have been allocated for transmission of the CSI feedback, the first indication matching a channel condition between the network device and the terminal device, and the second indication being generated by modifying the first indication based on the uplink resources; and

receiving precoding information for the CSI feedback from the terminal device on a second portion of the uplink resources based on the second indication, a size of a payload of the precoding information depending on the second indication.

7. The method of claim 6, wherein the uplink resources comprise resources on a Physical Uplink Shared Channel (PUSCH).

8. The method of claim 6, wherein the second indication is generated in a manner such that the payload of the precoding information generated based on the second indication can be carried by a portion of the uplink resources.

9. The method of claim 6, further comprising:

based on the first indication, sending resource allocation information to the terminal device, the resource allocation information relating to a portion of a second uplink resource for transmission of a second CSI feedback, the portion of the second uplink resource determined based on the first indication and capable of carrying a payload of second precoding information, the payload of the second precoding information expected to be determined by the terminal device based on the first indication.

10. The method of claim 6, wherein the CSI feedback is type IICSI feedback, and wherein the first indication comprises at least one of a Rank Indication (RI) matching the channel condition and a number of non-zero wideband amplitude coefficients per antenna layer.

11. A terminal device, comprising:

a processor; and

a memory coupled with the processor, the memory having instructions stored therein that, when executed by the processor, cause the terminal device to perform acts comprising:

12. The terminal device of claim 11, wherein the uplink resources comprise resources on a Physical Uplink Shared Channel (PUSCH).

13. The terminal device of claim 11, wherein generating the second indication comprises:

generating the second indication in a manner such that the payload of the precoding information generated based on the second indication can be carried by a portion of the uplink resources.

14. The terminal device of claim 11, further comprising:

15. The terminal device of claim 11, wherein the CSI feedback is type ii CSI feedback, wherein the first indication comprises at least one of a Rank Indication (RI) matching the channel condition and a number of non-zero wideband amplitude coefficients per antenna layer.

16. A network device, comprising:

a processor; and

a memory coupled with the processor, the memory having instructions stored therein that, when executed by the processor, cause the network device to perform acts comprising:

17. The network device of claim 16, wherein the uplink resources comprise resources on a Physical Uplink Shared Channel (PUSCH).

18. The network device of claim 16, wherein the second indication is generated in a manner such that the payload of the precoding information generated based on the second indication can be carried by a portion of the uplink resources.

19. The network device of claim 16, further comprising:

20. The network device of claim 16, wherein the CSI feedback is type ii CSI feedback, and wherein the first indication comprises at least one of a Rank Indication (RI) matching the channel condition and a number of non-zero wideband amplitude coefficients per antenna layer.

21. A computer-readable medium having stored thereon computer-executable instructions that, when executed by one or more processors, cause the one or more processors to perform the steps of the method of any one of claims 1-5.

22. A computer-readable medium having stored thereon computer-executable instructions that, when executed by one or more processors, cause the one or more processors to perform the steps of the method of any one of claims 6 to 10.