CN107733499B

CN107733499B - Communication method and apparatus for channel state information reporting

Info

Publication number: CN107733499B
Application number: CN201610657442.2A
Authority: CN
Inventors: 张晴川; 张闽
Original assignee: Nokia Shanghai Bell Co Ltd; Nokia Networks Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Oyj
Priority date: 2016-08-11
Filing date: 2016-08-11
Publication date: 2021-04-27
Anticipated expiration: 2036-08-11
Also published as: CN107733499A

Abstract

Embodiments of the present disclosure provide communication methods and apparatus for channel state information reporting. The method comprises the following steps: receiving, from a network device, a request for Channel State Information (CSI) for a channel between the network device and a terminal device, the request indicating reference signal resources for determining the CSI; and determining a delay budget based on a comparison of the number of reference signal resources to a first threshold number, the delay budget indicating a position of the first subframe relative to a second subframe in which the CSI is to be transmitted to the network device, the request to be received in the second subframe.

Description

Communication method and apparatus for channel state information reporting

Technical Field

Embodiments of the present disclosure relate generally to communication technology and, more particularly, to a communication method and apparatus for channel state information reporting.

Background

Beamformed channel state information reference signals (CSI-RS) are a very important feature introduced in Long Term Evolution (LTE) Release 13, which makes it possible to use large-scale antenna arrays in LTE systems without the need to define complex codebooks like traditional non-precoded CSI-RS. When the number of active terminal devices is small, the beamformed CSI-RS specific to the terminal device can achieve high CSI measurement quality and high reference signal efficiency using the group of microwave beams towards the terminal device. However, when the number of active terminal devices is large, CSI-RS overhead will be large. This becomes one of the main problems for terminal device specific beamformed CSI-RS.

In recent years, aperiodic CSI-RS has been introduced to at least partially address the issue of terminal device specific beamformed CSI-RS. Unlike the periodic CSI-RS, the aperiodic CSI-RS is transmitted to a specific terminal device only when needed, thereby improving the utilization of reference signal resources.

In the case of employing the aperiodic CSI-RS, a request for CSI for a channel between the network device and the terminal device (hereinafter also referred to as "CSI request") is transmitted to the terminal device in the same subframe as the aperiodic CSI-RS. Thus, unless a CSI request is received, the terminal device will not know to which subframe the CSI-RS belongs. This makes it impossible for the terminal device to process for CSI-RS in advance. In addition, the decoding time of the downlink control channel for transmitting the aperiodic CSI-RS further reduces the processing time of the terminal device. Therefore, the uncertainty of the occurrence of aperiodic CSI-RS and the decoding time of the downlink control channel make the delay budget (latency budget) for CSI reporting tight.

Disclosure of Invention

In general, embodiments of the present disclosure propose communication methods for channel state information reporting and corresponding devices.

In a first aspect, embodiments of the present disclosure provide a communication method. The method comprises the following steps: receiving, from a network device, a request for Channel State Information (CSI) for a channel between the network device and a terminal device, the request indicating reference signal resources for determining the CSI; and determining a delay budget based on a comparison of the number of reference signal resources to a first threshold number, the delay budget indicating a position of the first subframe relative to a second subframe in which the CSI is to be transmitted to the network device, the request to be received in the second subframe.

In a second aspect, embodiments of the present disclosure provide a method of communication. The method comprises the following steps: receiving, from a network device, a request for Channel State Information (CSI) for a channel between the network device and a terminal device, the request indicating a CSI process group associated with the CSI; and in response to the number of CSI processes in the CSI process group being greater than the number of available CSI processes, discarding at least a portion of the CSI processes in the CSI process group based on the type of CSI processes.

In a third aspect, embodiments of the present disclosure provide a method of communication. The method comprises the following steps: receiving, from a network device, a first type of reference signals and a second, different type of reference signals associated with a single Channel State Information (CSI) process, the second type of reference signals being generated based on CSI associated with the first type of reference signals; and at least transmitting Precoding Matrix Indication (PMI) information in the CSI associated with the first type of reference signals to the network equipment in response to resources required for transmitting the CSI associated with the first type of reference signals and the CSI associated with the second type of reference signals exceeding available uplink control channel resources.

In a fourth aspect, embodiments of the present disclosure provide a method of communication. The method comprises the following steps: receiving, from the network device, a first request for Channel State Information (CSI) for a channel between the network device and the terminal device in a third subframe, the first request indicating a first CSI process group associated with the CSI, CSI processes in the first CSI process group having indices; and in response to the number of CSI processes in the first CSI process group being above the number of available CSI processes, determining a subgroup of the first CSI process group, the subgroup comprising CSI processes in the first CSI process group having a high index, and the number of CSI processes in the subgroup being a difference between the number of CSI processes in the first CSI process group and the number of available CSI processes; and determining whether to report CSI for at least one CSI process in the subgroup within a threshold time.

In a fifth aspect, embodiments of the present disclosure provide a method of communication. The method comprises the following steps: receiving, from a network device, a request for Channel State Information (CSI) for a channel between the network device and a terminal device, the request indicating antenna ports for transmitting reference signals; and determining a delay budget based on the comparison of the number of antenna ports to the third threshold number, the delay budget indicating a position of the seventh subframe relative to the eighth subframe in which the reference signal is to be transmitted to the network device requesting reception in the eighth subframe.

In a sixth aspect, embodiments of the present disclosure provide a terminal device. The terminal device includes: a transceiver configured to receive a request from a network device for Channel State Information (CSI) for a channel between the network device and a terminal device, the request indicating reference signal resources for determining the CSI; and a controller coupled to the transceiver and configured to determine a delay budget based on a comparison of the number of reference signal resources to a first threshold number, the delay budget indicating a position of a first subframe relative to a second subframe in which CSI is to be transmitted to the network device, the request to be received.

In a seventh aspect, embodiments of the present disclosure provide a terminal device. The terminal device includes: a transceiver configured to receive a request from a network device for Channel State Information (CSI) for a channel between the network device and a terminal device, the request indicating a CSI process group associated with the CSI; and a controller coupled to the transceiver and configured to discard at least a portion of CSI processes in the CSI process group based on a type of CSI process in response to the number of CSI processes in the CSI process group being greater than the number of available CSI processes.

In an eighth aspect, embodiments of the present disclosure provide a terminal device. The terminal device includes: a transceiver configured to receive, from a network device, a first type of reference signals and a different second type of reference signals associated with a single Channel State Information (CSI) process, the second type of reference signals being generated based on CSI associated with the first type of reference signals; and a controller coupled to the transceiver and configured to at least transmit Precoding Matrix Indication (PMI) information in CSI associated with the first type of reference signal to the network device in response to resources required for transmitting CSI associated with the first type of reference signal and CSI associated with the second type of reference signal exceeding available uplink control channel resources.

In a ninth aspect, embodiments of the present disclosure provide a terminal device. The terminal device includes: a transceiver configured to receive, from a network device, a first request for Channel State Information (CSI) for a channel between the network device and a terminal device in a third subframe, the first request indicating a first CSI process group associated with the CSI, CSI processes in the first CSI process group having indices; and a controller coupled to the transceiver and configured to determine one subgroup of the first CSI process group in response to the number of CSI processes in the first CSI process group being above the number of available CSI processes, the subgroup including CSI processes in the first CSI process group having a high index, and the number of CSI processes in the subgroup being a difference between the number of CSI processes in the first CSI process group and the number of available CSI processes; and determining whether to report CSI for at least one CSI process in the subgroup within a threshold time.

In a tenth aspect, embodiments of the present disclosure provide a terminal device. The transceiver configured to receive a request from a network device for Channel State Information (CSI) for a channel between the network device and a terminal device, the request indicating an antenna port for transmitting a reference signal; and a controller coupled to the transceiver and configured to determine a delay budget based on a comparison of the number of antenna ports to a third threshold number, the delay budget indicating a position of a seventh subframe relative to an eighth subframe in which a reference signal is to be transmitted to the network device requesting reception.

It should be understood that the statements herein reciting aspects are not intended to limit the critical or essential features of the embodiments of the present disclosure, nor are they intended to limit the scope of the present 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 embodiments 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 illustrates an example communication network in which embodiments of the present disclosure may be implemented;

fig. 2 illustrates a flow diagram of an example communication method in accordance with certain other embodiments of the present disclosure;

fig. 3 illustrates a flow diagram of an example communication method in accordance with certain other embodiments of the present disclosure;

fig. 4 illustrates a flow diagram of an example communication method in accordance with certain other embodiments of the present disclosure;

fig. 5 illustrates a flow diagram of an example communication method in accordance with certain other embodiments of the present disclosure;

fig. 6 illustrates a flow chart of an example communication method in accordance with certain other embodiments of the present disclosure;

fig. 7 shows a schematic diagram of CSI reporting with certain other embodiments according to the present disclosure;

FIG. 8 illustrates a block diagram of an apparatus according to certain embodiments of the present disclosure;

fig. 9 shows a block diagram of an apparatus according to certain other embodiments of the present disclosure;

fig. 10 shows a block diagram of an apparatus according to certain other embodiments of the present disclosure;

fig. 11 shows a block diagram of an apparatus according to certain other embodiments of the present disclosure;

fig. 12 shows a block diagram of an apparatus according to certain other embodiments of the present disclosure; and

fig. 13 illustrates a block diagram of an apparatus in accordance with certain embodiments of the present disclosure.

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

Detailed Description

Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While certain embodiments of the present disclosure are shown in the drawings, it is to be understood that the present disclosure may be embodied in various forms and should not be construed as limited to the embodiments 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 embodiments of the disclosure are for illustration purposes only and are not intended to limit the scope of the disclosure.

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. In the context of the present disclosure, the terms "network device" and "base station" may be used interchangeably for purposes of discussion convenience, and may primarily be referred to as an eNB as an example of a network device.

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), and the above-described devices in a vehicle. In the context of the present disclosure, the terms "terminal device" and "user equipment" may be used interchangeably for purposes of discussion convenience.

The terms "include" and variations thereof as used herein are inclusive and open-ended, i.e., "including but not limited to. The term "based on" is "based, at least in part, on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment". Relevant definitions for other terms will be given in the following description.

Fig. 1 illustrates an example communication network 100 in which embodiments of the present disclosure may be implemented. Communication network 100 includes network device 110 and terminal device 120.

In a particular subframe (e.g., the nth subframe), network device 110 sends (101) a CSI request to terminal device 120, the request indicating reference signal resources for determining CSI. In case of aperiodic CSI-RS, the network device 110 sends a CSI request to the terminal device 120 in this specific subframe together with the aperiodic CSI-RS. Thus, only after receiving a CSI request, the terminal device 120 can measure the aperiodic CSI-RS to determine CSI by decoding the downlink control channel used to transmit the CSI request.

The LTE specification specifies a delay budget for which terminal device 120 should report CSI to network device 110 that indicates the location of the subframe in which CSI is to be reported to network device 110 relative to the subframe in which the CSI request is received. According to current LTE specifications, the delay budget is specified as 4. In other words, if terminal device 120 receives a CSI request in the nth subframe, terminal device 120 should report CSI for the CSI request by network device 110 in the (n + 4) th subframe (102). However, the uncertainty of the presence of aperiodic CSI-RS and the decoding time of the downlink control channel strain the delay budget. Furthermore, in case that a plurality of reference signal resources are configured for the terminal device 120, the terminal device 120 needs to measure the plurality of reference signal resources, which makes the delay budget more strained.

To at least partially address the above-mentioned and other potential drawbacks and problems in the conventional approaches, embodiments of the present disclosure propose increasing a delay budget for reporting CSI with aperiodic CSI-RS to ensure that terminal devices have sufficient processing time to perform reference signal measurements and calculations.

It should be understood that the number of network devices and the number of terminal devices shown in fig. 1 are for illustration purposes only and are not intended to be limiting. Communication network 100 may include any suitable type and number of network devices, each network device may provide any suitable number of cells, and communication network 100 may also include any suitable number of terminal devices.

Communication between network device 110 and terminal device 120 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. Moreover, the communication may utilize any suitable wireless communication technique including, but not limited to, Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple Input Multiple Output (MIMO), orthogonal frequency division multiple access (OFDM), and/or any other technique now known or later developed. It should be noted that although the embodiments of the present disclosure have been described mainly using a Long Term Evolution (LTE) system as an example, this is merely exemplary, and the technical solution of the present disclosure can be fully applied to other suitable existing or future-developed systems.

An embodiment of the present disclosure is described in more detail below by means of fig. 2. Fig. 2 illustrates a flow diagram of a communication method 200 according to some embodiments of an aspect of the present disclosure. It is to be appreciated that method 200 may be implemented by a terminal device 120 such as shown in fig. 1. It should be understood that method 200 may also include additional steps not shown and/or may omit steps shown, as the scope of the present disclosure is not limited in this respect. For purposes of discussion, the method 200 will be described below in conjunction with FIG. 1.

Method 200 begins at 210, where terminal device 120 receives a request from network device 110 for CSI for a channel between network device 110 and terminal device 120 (hereinafter also referred to as a "CSI request") indicating reference signal resources for determining CSI. In some embodiments, the reference signal resource is a CSI-RS resource. In other embodiments, the reference signal resources may be any other type of RS resource that can be used to estimate the desired signal, such as Common Reference Signal (CRS) resources.

At 220, terminal device 120 determines a delay budget based on a comparison of the number of reference signal resources to a threshold number. The delay budget indicates a position of the second subframe relative to the first subframe. A request for CSI is received in a first subframe, and CSI is to be transmitted to network device 110 in a second subframe.

In some embodiments, determining the delay budget comprises: determining an offset based on a comparison of the number of reference signal resources to a threshold number; and increasing the reference delay budget by the offset to obtain the delay budget. In some embodiments, determining the offset comprises: the offset is increased by a first predetermined amount in response to the number of reference signal resources being greater than the threshold number.

Consider a specific example. In this particular example, terminal device 120 may determine the delay budget based on the following expression:

L＝L₀+δ (1)

where L denotes the delay budget, L₀Representing the reference delay budget and delta the offset.

Reference delay budget L₀May take a value specified in the current LTE specifications, e.g. 4. Of course, the reference delay budget L₀Any other value that may be taken is also possible. The scope of the present disclosure is not limited in this respect.

One or more thresholds for the number of reference signal resources may be predefined for terminal device 120, and the offset δ may be determined based on a comparison of the number of reference signal resources to the one or more thresholds. As one example, terminal device 120 may determine offset δ based on the following expression

Wherein y is₁，…，y_MM predefined thresholds representing the number of reference signal resources, M may be in the range of 1 to 10, for example. If the number of reference signal resources is greater than y_mThen, I_ym1, otherwise I_ym0. For example, in the case where M is 3, y₁、y₂And y₃And may be 4, 6 and 8, respectively. If the number of reference signal resources is 8, then

At this time, the offset δ is 2.

With embodiments of the present disclosure, a delay budget is determined based on a comparison of a number of reference signal resources to a threshold number. As the number of reference signal resources configured increases, the determined delay budget also increases. Thereby, it is ensured that the terminal device has sufficient processing time to perform reference signal measurements and calculations.

As is known, CSI requests may be transmitted on a downlink control channel. Examples of the downlink control channel include, but are not limited to: physical downlink control information (PDCCH) and enhanced physical downlink control information (ePDCCH). When the CSI request is transmitted on the ePDCCH, the decoding time of the ePDCCH by the terminal device 120 will be longer compared to the PDCCH. Thus, when terminal device 120 receives a CSI request on the ePDCCH, the delay budget in expression (2) may be further increased based on the following expression to ensure that the terminal device has sufficient processing time to make reference signal measurements and calculations:

wherein if the CSI request is received on ePDCCH, I_ePDCCH1, otherwise I_ePDCCH＝0。

As can be seen from expression (3), when a CSI request is received on ePDCCH, the terminal device 120 may further increase the delay budget to ensure that there is sufficient processing time to make reference signal measurements and calculations.

A scheme for determining a delay budget based on a comparison of a number of reference signal resources to a threshold number is described above with reference to fig. 2. Since the reference signal resources are associated with a set of antenna ports, the delay budget may also be determined based on a comparison of the number of antenna ports to another threshold number.

An embodiment of the present disclosure is described in more detail below by means of fig. 3. Fig. 3 illustrates a flow diagram of a communication method 300 according to some embodiments of an aspect of the present disclosure. It is to be appreciated that method 300 may be implemented by a terminal device 120 such as shown in fig. 1. It should be understood that method 300 may also include additional steps not shown and/or may omit steps shown, as the scope of the present disclosure is not limited in this respect. For purposes of discussion, the method 300 will be described below in conjunction with FIG. 1.

Method 300 begins at 310, where terminal device 120 receives a request from network device 110 for CSI for a channel between network device 110 and terminal device 120 (hereinafter also referred to as a "CSI request") indicating antenna ports for transmission of reference signals.

At 320, terminal device 120 determines a delay budget based on a comparison of the number of antenna ports to a third threshold number. The delay budget indicates a position of the seventh subframe relative to the eighth subframe. The reference signal will be transmitted to the network device 110 in the seventh subframe and the CSI request is received in the eighth subframe. It should be appreciated that one reference signal resource may be associated with a set of antenna ports. For example, one reference signal resource may be associated with eight antenna ports. Thus, the third threshold number used for comparison to the number of antenna ports in method 300 should be different from the first threshold number used for comparison to the number of reference signal resources in method 200.

In some embodiments, determining the delay budget comprises: determining an offset based on a comparison of the number of antenna ports to a third threshold number; and increasing the reference delay budget by an offset to obtain the delay budget.

In some embodiments, determining the offset comprises: the offset is increased by a third predetermined amount in response to the number of antenna ports being greater than a third threshold number.

In some embodiments, determining the offset further comprises: the offset is increased by a fourth predetermined amount, which may be the same or different from the third predetermined amount, in response to the request being received on the given downlink control channel.

In some embodiments, receiving the request includes receiving a request for aperiodic CSI.

It should be understood that the various features described above with reference to fig. 2 are equally applicable to the method 300 and thus will not be described in further detail.

The current LTE specifications provide that multiple CSI processes can be configured for a terminal device, which can be triggered by one CSI request. Furthermore, current LTE specifications (e.g. LTE Release 13) also specify rules for dropping CSI processes when there is a conflict between multiple CSI requests. In particular, the current LTE specifications specify the maximum number of CSI processes (by N) that a terminal device can support_xTo indicate). If the number of CSI processes needing to be processed by the terminal equipment in a single subframe exceeds the maximum CSI process number N_x(mainly due to network devices frequently sending CSI requests to terminal devices within an interval of multiple subframes), the terminal device should discard CSI processes with high indices associated with the most recently received CSI requests. In case of aperiodic CSI-RS, thisA simple dropping rule may make dropping of CSI processes occur more frequently.

To at least partially solve the above problem, embodiments of the present disclosure propose to drop a partial CSI process based on a type of the CSI process when the number of CSI processes indicated in the CSI request is greater than the number of available CSI processes, thereby making a dropping operation of the CSI process more reasonable.

An embodiment of the present disclosure is described in more detail below by means of fig. 4. Fig. 4 illustrates a flow diagram of a communication method 400 according to some embodiments of an aspect of the present disclosure. It is to be appreciated that method 400 may be implemented by a terminal device 120 such as shown in fig. 1. It should be understood that method 400 may also include additional steps not shown and/or may omit steps shown, as the scope of the disclosure is not limited in this respect. For purposes of discussion, the method 400 will be described below in conjunction with FIG. 1.

Method 400 begins at 410, where terminal device 120 receives a request from network device 110 for CSI for a channel between network device 110 and terminal device 120, the request indicating a CSI process group associated with the CSI.

At 420, in response to the number of CSI processes in the CSI process group being greater than the number of available CSI processes, at least a portion of the CSI processes in the CSI process group are dropped based on the type of CSI process.

In some embodiments, the type of CSI process is a process configured with aperiodic reference signals or a process configured with periodic reference signals.

In some embodiments, CSI processes configured with aperiodic reference signals are given higher processing priority. In other words, in case the number of CSI processes in the CSI process group is greater than the number of available CSI processes, the processes configured with aperiodic reference signals are preferentially reserved.

Specifically, assume that the CSI process group includes N_A-CSI-RSA process configured with aperiodic reference signal and N_P-CSI-RSThe maximum number of CSI processes that can be supported by the terminal device is represented by the number of processes configured with periodic reference signalsN_xThe number of the CSI processes which are not reported is represented as N_u. In other words, only N in processes configured with aperiodic reference signals₁＝min{N_A-CSI-RS，max{N_x-N_u0} of processes and processes configured with periodic reference signals₂＝min{N_P-CSI-RS，max{N_x-N_u-N₁0} is reserved for processing.

Since processes configured with aperiodic reference signals are triggered on demand, embodiments according to the present disclosure can ensure that these processes have a higher processing priority than processes configured with periodic reference signals, thereby enabling processing with low latency.

In addition to aperiodic CSI-RS as discussed above, current LTE specifications (e.g., LTE Release 14) also support employing hybrid CSI-RS transmission in CSI feedback architectures. The CSI feedback architecture generally constructs multi-stage CSI feedback, wherein the first-stage CSI feedback is obtained by the terminal device measuring a first type of CSI-RS from the network device over a full bandwidth, and the second-stage CSI feedback is obtained by the terminal device measuring a second type of CSI-RS generated according to the first-stage CSI feedback.

In particular, wideband Precoding Matrix Indicator (PMI) information is included in both the first-stage CSI feedback and the second-stage CSI feedback, and both the first-stage CSI feedback and the second-stage CSI feedback are performed on an uplink control channel. When the resources required for the first-stage CSI feedback and the second-stage CSI feedback exceed the available uplink control channel resources (e.g., PUCCH resources), part of the feedback information in the first-stage CSI feedback and the second-stage CSI feedback cannot be transmitted on the uplink control channel.

To at least partially address the above issues, embodiments of the present disclosure propose to give higher priority to PMI information in first-stage CSI feedback to ensure generation of a second type of CSI-RS to be used in second-stage CSI feedback.

An embodiment of the present disclosure is described in more detail below by means of fig. 5. Fig. 5 illustrates a flow chart of a communication method 500 according to some embodiments of an aspect of the disclosure. It is to be appreciated that method 500 may be implemented by a terminal device 120 such as shown in fig. 1. It should be understood that method 500 may also include additional steps not shown and/or may omit steps shown, as the scope of the present disclosure is not limited in this respect. For purposes of discussion, the method 500 will be described below in conjunction with fig. 1.

Method 500 begins at 510, where terminal device 120 receives a first type of reference signal and a second, different type of reference signal associated with a single CSI process from network device 110, the second type of reference signal being generated based on CSI associated with the first type of reference signal.

At 520, in response to the resources required for transmitting the CSI associated with the first type of reference signal and the CSI associated with the second type of reference signal exceeding available uplink control channel resources, the terminal device 120 transmits at least PMI information in the CSI associated with the first type of reference signal to the network device 110.

According to the embodiment of the disclosure, when the first type and the second type CSI-RSs are configured in a single CSI process, if conflict exists between feedback of PMI information associated with the first type CSI-RSs and other types of feedback, the PMI information associated with the first type CSI-RSs is preferentially fed back, and part or all of the other types of feedback are discarded according to a discarding principle specified in the current LTE specification. Other types of feedback may include, but are not limited to, feedback on at least one of the following: a CSI-RS resource indication (CRI), a Rank Indication (RI), wideband or subband PMI information associated with the second type of CSI-RS, a wideband or subband CQI associated with the second type of CSI-RS.

Note that if both first and second type CSI-RS are not configured in a single CSI process, or PMI information is only associated with second type CSI-RS in case first and second type CSI-RS are configured, the dropping principle specified in the current LTE specification is still employed.

In the embodiments of the present disclosure described with reference to fig. 2 and 3, the delay budget for reporting CSI is increased to ensure that the terminal device has sufficient processing time to perform reference signal measurements and calculations. However, increasing the delay budget for reporting CSI also increases the chance of collisions between CSI requests. Therefore, the dropping of CSI processes may occur more frequently if the dropping rule specified in LTE Release 13 is still employed. This is clearly undesirable.

To at least partially address the above issues, embodiments of the present disclosure propose a new CSI reporting framework. In a new CSI reporting framework, when the number of CSI processes triggered by a CSI request is greater than the number of available CSI processes, instead of directly discarding CSI processes that cannot be processed in the current subframe, it is determined whether to report CSI for at least one of the CSI processes within a threshold time. Reporting the CSI for at least one of the CSI processes if the CSI can be reported with a subsequent Uplink (UL) grant within the threshold time. Discarding at least one of the CSI processes if CSI for the CSI process cannot be reported with a subsequent Uplink (UL) grant within the threshold time.

An embodiment of the present disclosure is described in more detail below by means of fig. 6. Fig. 6 illustrates a flow diagram of a communication method 600 according to some embodiments of an aspect of the disclosure. It is to be appreciated that method 600 may be implemented by a terminal device 120 such as shown in fig. 1. It should be understood that method 600 may also include additional steps not shown and/or may omit steps shown, as the scope of the disclosure is not limited in this respect. For purposes of discussion, the method 600 will be described below in conjunction with FIG. 1.

Method 600 begins at 610, where terminal device 120 receives a first request for CSI for a channel between network device 110 and terminal device 120 (hereinafter also referred to as a "first CSI request") from network device 110 in a third subframe. The first CSI request indicates a first CSI process group associated with the CSI. One or more CSI processes may be included in the first CSI process group. The CSI processes in the first CSI process group have indices.

At 620, in response to the number of CSI processes in the first CSI process group being above the number of available CSI processes, determining a subgroup of the first CSI process group, the subgroup including CSI processes in the first CSI process group having a high index, and the number of CSI processes in the subgroup being a difference between the number of CSI processes in the first CSI process group and the number of available CSI processes; and determining whether to report CSI for at least one CSI process in the subgroup within a threshold time.

In the present disclosure, the "number of available CSI processes" refers to a difference between the maximum number of CSI processes that can be supported by the terminal device and the number of CSI processes that have not been reported.

In some embodiments, the method 600 further comprises: in a third subframe, storing CSI processes in the subgroup in an ordered list in an order of CSI process with high index first and CSI process with low index second

In some embodiments, the ordered list may be implemented as a queue. A queue may have put and pop operations. In some embodiments, the relationship between the put operation and the pop operation is such that the queue is a Last In First Out (LIFO) queue. In a LIFO queue, the element that was last added to the queue is the element that was first fetched.

In some embodiments, the method 600 further comprises: in a fourth subframe after the third subframe, in response to determining that there is an uplink grant from the network device, determining whether to process at least one CSI process in the subgroup.

In some embodiments, determining whether to process at least one CSI process in the subgroup comprises: in response to receiving a second request for CSI for the channel from the network device in the fourth subframe, the second request indicating a second CSI process group associated with the CSI, the CSI processes in the second CSI process group having indices, the CSI processes in the second CSI process group being stored in the ordered list in an order that a CSI process with a high index precedes and a CSI process with a low index succeeds; and determining to process at least one CSI process in the subgroup in response to the number of CSI processes in the second CSI process group being less than the number of available CSI processes.

In some embodiments, processing at least one CSI process in the subgroup comprises: acquiring the CSI processes in the second CSI process group and at least one CSI process in the sub-groups from the ordered list in the order of the CSI processes which are preferentially acquired and then put into the storage list according to the number of the available CSI processes; and removing the acquired CSI processes from the ordered list.

In some embodiments, determining whether to process at least one CSI process in the subgroup comprises: in response to not receiving a second request for CSI of a channel from the network device in the fourth subframe, acquiring at least one CSI process in the subgroup from the ordered list in an order of CSI processes placed in the storage list after being preferentially acquired according to the number of available CSI processes; and removing the acquired CSI processes from the ordered list.

In some embodiments, the method 600 further comprises: determining a latency of the CSI processes stored in the ordered list; and responsive to the latency of one of the CSI processes being above a threshold time, discarding the one of the CSI processes.

Consider a specific example. In this particular example, the maximum number of CSI processes that terminal device 120 can support is defined by N_xIs represented by the number of available CSI processes being N_aDenoted by Q, the LIFO queue is denoted by T, the threshold time is denoted by T, and the latency of each CSI process is denoted by WT. Number N of available CSI processes_aInitialisation to N_xThe LIFO queue Q is initialized to empty and the latency WT of each CSI process is initialized to 0. In the nth subframe, the terminal device 120 needs to perform the following operations in sequence:

(i) it is determined whether there is an UL transmission and a configured CSI report in the current subframe. If so, let N_a＝N_a+ b, where b represents the number of CSI processes whose CSI is to be reported in the current subframe.

(ii) It is determined whether there is an UL grant in the current subframe and whether there is a CSI request associated with the UL grant. And if both the indexes are met, putting the CSI processes in the CSI process group indicated by the CSI request into a queue Q according to the ascending order of the indexes, namely putting the CSI processes with high indexes first and then putting the CSI processes with low indexes.

(iii) It is determined whether an UL grant is present in the current subframe. If so, take c-min { Q, N out of queue Q_aAnd processes the CSI processes, where Q represents the number of CSI processes in queue Q. The CSI for the fetched c CSI processes will be reported to network device 110 in subframes n + L subframes, where L represents the delay budget. Here, the terminal device 120 may determine the delay budget L according to the embodiment described with reference to fig. 2. For the sake of brevity, several features described with reference to fig. 2 will not be repeated. Further, terminal device 120 is according to N_a＝N_aC to update N_a。

(iv) The latencies WT of all CSI processes in queue Q are updated by increasing them by 1. If the latency WT of a particular CSI process in queue Q is greater than a threshold time T, then the particular CSI process is dropped by removing it from queue Q.

This specific example is described in more detail below with reference to fig. 7. In the specific example shown in fig. 7, it is assumed that the maximum number N of CSI processes that can be supported by the terminal device 120 is_xIs 5. Of course, this is merely an example, and the maximum number of CSI processes N that terminal device 120 can support is_xAny suitable value may be taken.

As shown, in subframe S1, terminal device 120 determines that there is no UL transmission and configured CSI report in the current subframe and determines that there is no UL grant in the current subframe, and thus the number N of available CSI processes_aAnd the contents of the LIFO queue Q are not updated.

In subframe S2, terminal device 120 determines that there is an UL grant and CSI request associated therewith in the current subframe. The CSI request indicates 3 CSI processes associated with CSI. In other words, the CSI request triggers 3 CSI processes (also referred to as "trigger a"). Therefore, these 3 CSI processes are also referred to as CSI processes associated with trigger a and are denoted CP #1_ a, CP #2_ a, CP #3_ a. Subsequently, the terminal device 120 puts the CSI processes CP #1_ a, CP #2_ a, CP #3_ a into the queue Q (as shown by 710). Then, the terminal device 120 extracts the CSI processes CP #1_ a, CP #2_ a, and CP #3_ a from the queue Q (in this case, c is 3). To is directed atThe CSI for the fetched 3 CSI processes will be reported to network device 110 in subframe S6 (as shown by 760). Further, terminal device 120 is according to N_a＝N_aC to react N with_aThe update is 2.

In subframe S3, similar to in subframe S1, terminal device 120 determines that there is no UL transmission and configured CSI report in the current subframe and determines that there is no UL grant in the current subframe, and thus the number N of available CSI processes_aAnd the contents of the LIFO queue Q are not updated.

In subframe S4, terminal device 120 determines that there is an UL grant and CSI request associated therewith in the current subframe. The CSI request indicates 4 CSI processes associated with CSI. In other words, the CSI request triggers 4 CSI processes (also referred to as "trigger b"). Therefore, these 4 CSI processes are also referred to as CSI processes associated with trigger b and are denoted CP #1_ b, CP #2_ b, CP #3_ b, CP #4_ b. Subsequently, the terminal device 120 puts the CSI processes CP #1_ b, CP #2_ b, CP #3_ b, CP #4_ b into the queue Q (as shown in 720 and 730). Then, the terminal device 120 extracts the CSI processes CP #1_ b and CP #2_ b from the queue Q (in this case, c ═ min {4,2} ═ 2). The CSI for the fetched 2 CSI processes will be reported to network device 110 in subframe S8 (as shown by 770). Further, terminal device 120 is according to N_a＝N_aC to react N with_bIs updated to 0.

In subframe S5, similar to in subframe S1, terminal device 120 determines that there is no UL transmission and configured CSI report in the current subframe and determines that there is no UL grant in the current subframe, and thus the number N of available CSI processes_aAnd the contents of the LIFO queue Q are not updated.

In subframe S6, terminal device 120 determines that there is UL transmission and configured CSI report in the current subframe, and therefore reports CSI for CSI processes CP #1_ a, CP #2_ a, CP #3_ a to network device 110 in subframe S6 (as shown by 760), and according to N_a＝N_a+ b to separate N_aUpdated to 3. Terminal device 120 then determines that there is an UL grant and CSI request associated therewith in the current subframe. The CSI request indicates 1 CSI process associated with CSI. In other words, the CSI request triggers 1 CSI process(also referred to as "trigger c"). Therefore, this CSI process is also referred to as the CSI process associated with trigger c and is denoted CP #1_ c. Subsequently, terminal device 120 places CSI process CP #1_ c in queue Q (as shown at 750). Then, the terminal device 120 extracts the CSI processes CP #1_ c, CP #3_ b, and CP #4_ b from the queue Q (in this case, c is min {3,3} -, 3). The CSI for the fetched 3 CSI processes will be reported to network device 110 in subframe S10 (as shown at 780). Further, terminal device 120 is according to N_a＝N_aC to react N with_aIs updated to 0.

As can be seen from fig. 7, although the CSI processes CP #3_ b and CP #4_ b associated with trigger b are not immediately processed in sub-frame S4, they are not immediately discarded, but rather are buffered in queue Q, and are taken out of queue Q for processing with a UL grant in subsequent sub-frame S6, and the CSI for CSI processes CP #3_ b and CP #4_ b is reported to network device 110 in sub-frame S10. Thus, according to embodiments of the present disclosure, the dropping probability of CSI processes is significantly reduced by effectively utilizing uplink resources.

With continued reference to fig. 7. If terminal device 120 determines in subframe S7 that there is an UL grant and a CSI request associated therewith, since the number N of CSI processes available at this time is_a0, so the processing of the CSI process indicated by the CSI request will be temporarily blocked. This will delay the CSI report from the newly received CSI request.

To solve this problem, embodiments of the present disclosure give low priority to CSI processes that do not start processing in a subframe in which a CSI request is received, and give high priority to CSI processes associated with a newly received CSI request, thereby ensuring that the newly received CSI request has a low feedback delay.

In this regard, the method 500 further includes: receiving, from the network device, a third request for CSI for the channel in a fifth subframe subsequent to the fourth subframe, the third request indicating a third CSI process group associated with the CSI; and in response to the number of CSI processes in the third CSI process group being greater than the number of available CSI processes, determining that at least one CSI process in the subgroup is being processed and terminating the processing of the at least one CSI process in the subgroup according to a difference between the number of CSI processes in the third CSI process group and the number of available CSI processes.

In particular, assume that the number of CSI processes associated with a newly received CSI request is denoted as/and that/is greater than the number N of available CSI processes_aThen terminal device 120 may terminate d = min { N ″_b，l-N_aA number of processes with low priority, where N_bIndicating an active low priority process. Thereafter, terminal device 120 may take d CSI processes associated with the newly received CSI request from queue Q for processing. In this disclosure, "active low priority process" refers to a low priority process that has been taken out of queue Q but whose CSI reporting has not yet been completed. Thus, embodiments of the present disclosure provide a more reliable and efficient CSI reporting scheme when aperiodic reference signals are employed.

Fig. 8 illustrates a block diagram of an apparatus 800 according to certain embodiments of the present disclosure. It is to be appreciated that apparatus 800 may be implemented on the side of terminal device 120 shown in fig. 1. As shown in fig. 8, apparatus 800 (e.g., terminal device 120) comprises: a first receiving unit 810 configured to receive, from a network device, a request for Channel State Information (CSI) of a channel between the network device and the terminal device, the request indicating reference signal resources for determining the CSI; and a first determining unit 820 coupled to the first receiving unit 810 and configured to determine a delay budget based on a comparison of the number of reference signal resources with a first threshold number, the delay budget indicating a position of a first subframe relative to a second subframe in which CSI is to be transmitted to the network device, requesting reception.

In some embodiments, the first determining unit 820 is further configured to: determining an offset based on a comparison of the number of reference signal resources to a first threshold number; and increasing the reference delay budget by an offset to obtain the delay budget.

In some embodiments, the first determining unit 820 is further configured to: the offset is increased by a first predetermined amount in response to the number of reference signal resources being greater than a first threshold number.

In some embodiments, the first determining unit 820 is further configured to: the offset is increased by a second predetermined amount, which may be the same or different from the first predetermined amount, in response to the request being received on the given downlink control channel.

In some embodiments, the first receiving unit 810 is further configured to: a request for aperiodic CSI is received.

Fig. 9 illustrates a block diagram of an apparatus 900 according to certain embodiments of the present disclosure. It is to be appreciated that apparatus 900 can be implemented on the side of terminal device 120 shown in fig. 1. As shown in fig. 9, apparatus 900 (e.g., terminal device 120) includes: a second receiving unit 910 configured to receive, from a network device, a request for Channel State Information (CSI) of a channel between the network device and a terminal device, the request indicating a CSI process group associated with the CSI; and a dropping unit 920 coupled to the second receiving unit 910 and configured to drop at least a portion of CSI processes in the CSI process group based on a type of CSI processes in response to the number of CSI processes in the CSI process group being greater than the number of available CSI processes.

In some embodiments, the CSI process group includes a first number of processes configured with aperiodic reference signals and a second number of processes configured with periodic reference signals, the first number of processes having indices, and the discard unit 920 is further configured to: in response to the first number being above the number of available CSI processes, dropping the second number of processes and dropping processes of the first number of processes that have a high index.

In some embodiments, the second number of processes has an index; and wherein the discarding unit 920 is further configured to: in response to the first number being less than the number of available CSI processes, dropping processes with high indices of the second number of processes based on a difference between the first number and the number of available CSI processes.

Fig. 10 illustrates a block diagram of an apparatus 1000 in accordance with certain embodiments of the present disclosure. It is understood that the apparatus 1000 may be implemented on the side of the terminal device 120 shown in fig. 1. As shown in fig. 10, apparatus 1000 (e.g., terminal device 120) includes: a third receiving unit 1010 configured to receive, from a network device, a first type of reference signals and a second, different type of reference signals associated with a single Channel State Information (CSI) process, the second type of reference signals being generated based on CSI associated with the first type of reference signals; and a transmitting unit 1020 coupled to the third receiving unit 1010 and configured to transmit at least Precoding Matrix Indication (PMI) information in CSI associated with the first type of reference signals to the network device in response to resources required for transmitting CSI associated with the first type of reference signals and CSI associated with the second type of reference signals exceeding available uplink control channel resources.

Fig. 11 illustrates a block diagram of an apparatus 1100 in accordance with certain embodiments of the present disclosure. It is to be appreciated that apparatus 1100 can be implemented on the side of terminal device 120 shown in fig. 1. As shown in fig. 11, apparatus 1100 (e.g., terminal device 120) includes: a fourth receiving unit 1110 configured to receive, from the network device, a first request for Channel State Information (CSI) of a channel between the network device and the terminal device in the third subframe, the first request indicating a first CSI process group associated with CSI, CSI processes in the first CSI process group having indexes; and a second determining unit 1120 coupled to the fourth receiving unit 1110 and configured to determine one subgroup of the first CSI process group in response to the number of CSI processes in the first CSI process group being above the number of available CSI processes, the subgroup including CSI processes of the first CSI process group having a high index, and the number of CSI processes in the subgroup being a difference between the number of CSI processes in the first CSI process group and the number of available CSI processes; and determining whether to report CSI for at least one CSI process in the subgroup within a threshold time.

In some embodiments, the second determining unit 1120 is further configured to: in a third subframe, the CSI processes in the subgroup are stored in the ordered list in an order in which CSI processes with high indices precede CSI processes with low indices succeed.

In some embodiments, the second determining unit 1120 is further configured to: in a fourth subframe after the third subframe, in response to determining that there is an uplink grant from the network device, determining whether to process at least one CSI process in the subgroup.

In some embodiments, the second determining unit 1120 is further configured to: in response to receiving a second request for CSI for the channel from the network device in the fourth subframe, the second request indicating a second CSI process group associated with the CSI, the CSI processes in the second CSI process group having indices, the CSI processes in the second CSI process group being stored in the ordered list in an order that a CSI process with a high index precedes and a CSI process with a low index succeeds; and determining to process at least one CSI process in the subgroup in response to the number of CSI processes in the second CSI process group being less than the number of available CSI processes.

In some embodiments, the second determining unit 1120 is further configured to: acquiring the CSI processes in the second CSI process group and at least one CSI process in the sub-groups from the ordered list in the order of the CSI processes which are preferentially acquired and then put into the storage list according to the number of the available CSI processes; and removing the acquired CSI processes from the ordered list.

In some embodiments, the second determining unit 1120 is further configured to: in response to not receiving a second request for CSI of a channel from the network device in the fourth subframe, acquiring at least one CSI process in the subgroup from the ordered list in an order of CSI processes placed in the storage list after being preferentially acquired according to the number of available CSI processes; and removing the acquired CSI processes from the ordered list.

In some embodiments, the second determining unit 1120 is further configured to: determining a latency of the CSI processes stored in the ordered list; and responsive to the latency of one of the CSI processes being above a threshold time, discarding the one of the CSI processes.

In some embodiments, the second determining unit 1120 is further configured to: receiving, from the network device, a third request for CSI for the channel in a fifth subframe subsequent to the fourth subframe, the third request indicating a third CSI process group associated with the CSI; determining that at least one CSI process in the subgroup is being processed in response to the number of CSI processes in the third CSI process group being greater than the number of available CSI processes; and terminating processing of at least one CSI process in the subgroup according to a difference between the number of CSI processes in the third CSI process group and the number of available CSI processes.

In some embodiments, CSI processes with low indices in CSI processes in the subgroup are configured with aperiodic reference signals.

In some embodiments, CSI processes with high indices among CSI processes in the sub-process group are configured with periodic reference signals.

In some embodiments, the first request further indicates reference signal resources for determining CSI.

In some embodiments, the second determining unit 1120 is further configured to: determining a delay budget based on a comparison of the number of reference signal resources to a second threshold number, the delay budget indicating a location of a sixth subframe relative to a third subframe in which the CSI is to be transmitted to the network device.

In some embodiments, the second determining unit 1120 is further configured to: determining an offset based on a comparison of the number of reference signal resources to a second threshold number; and

the reference delay budget is increased by an offset to obtain the delay budget.

In some embodiments, the second determining unit 1120 is further configured to: the offset is increased by a first predetermined amount in response to the number of reference signal resources being greater than a second threshold number.

In some embodiments, the second determining unit 1120 is further configured to: the offset is increased by a second predetermined amount, which may be the same or different from the first predetermined amount, in response to the first request being received on the given downlink control channel.

Fig. 12 illustrates a block diagram of an apparatus 1200 in accordance with certain embodiments of the present disclosure. It is understood that apparatus 1200 may be implemented on the side of terminal device 120 shown in fig. 1. As shown in fig. 12, apparatus 1200 (e.g., terminal device 120) includes: a fifth receiving unit 1210 configured to receive a request for Channel State Information (CSI) of a channel between the network device and the terminal device from the network device, the request indicating an antenna port for transmitting a reference signal; and a third determining unit 1220, coupled to the fifth receiving unit 1210 and configured to determine a delay budget based on a comparison of the number of antenna ports with a third threshold number, the delay budget indicating a position of a seventh subframe relative to an eighth subframe in which a reference signal is to be transmitted to the network device requesting reception in the eighth subframe.

In some embodiments, the third determining unit 1220 is further configured to: determining an offset based on a comparison of the number of antenna ports to a third threshold number; and increasing the reference delay budget by an offset to obtain the delay budget.

In some embodiments, the third determining unit 1220 is further configured to: the offset is increased by a third predetermined amount in response to the number of antenna ports being greater than a third threshold number.

In some embodiments, the third determining unit 1220 is further configured to: the offset is increased by a fourth predetermined amount, which may be the same or different from the third predetermined amount, in response to the request being received on the given downlink control channel.

In some embodiments, the fifth receiving unit 1210 is further configured to: a request for aperiodic CSI is received.

It should be understood that each of the units described in the apparatus 800-1200 respectively corresponds to each of the steps in the method 200-600 described with reference to fig. 1-7. Therefore, the operations and features described above with reference to fig. 1 to 7 are also applicable to the device 800 and the units included therein, and have the same effects, and the detailed description is omitted here.

The units included in the apparatus 700 and the apparatus 800 may be implemented in various ways, including software, hardware, firmware, or any combination thereof. In one embodiment, one or more of the units may be implemented using software and/or firmware, such as machine executable instructions stored on a storage medium. In addition to, or in the alternative to, machine-executable instructions, some or all of the elements in apparatus 700 and apparatus 800 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 elements shown in fig. 8-12 may be implemented partially or wholly as hardware modules, software modules, firmware modules, or any combination thereof. In particular, in some embodiments, the procedures, methods, or processes described above may be implemented by hardware in a network device or a terminal device. For example, the network device or the terminal device may utilize its transmitter, receiver, transceiver and/or processor or controller to implement the

method

200 and 600.

Fig. 13 illustrates a block diagram of a device 1300 suitable for implementing embodiments of the present disclosure. Device 1300 may be used to implement a terminal device, such as terminal device 120 shown in fig. 1.

As shown, the device 1300 includes a controller 1310. The controller 1310 controls the operation and functions of the device 1300. For example, in certain embodiments, the controller 1310 may perform various operations by way of instructions 1330 stored in a memory 1320 coupled thereto. The memory 1320 may be of any suitable type suitable to the local technical environment and may be implemented using any suitable data storage technology, including but not limited to semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems. Although only a single memory unit is illustrated in FIG. 13, there may be multiple physically distinct memory units within the device 1300.

The controller 1310 may be of any suitable type suitable to the local technical environment, and may include, but is not limited to, one or more of a general purpose computer, a special purpose computer, a microcontroller, a digital signal controller (DSP), and a controller-based multi-core controller architecture. The device 1300 may also include a plurality of controllers 1310. The controller 1310 is coupled to a transceiver 1340 that may enable the transceiver 1340 to receive and transmit information via one or more antennas 1350 and/or other components.

When the device 1300 is acting as the network device 140, the controller 1310 and the transceiver 1340 may cooperate to implement the method 300 described above with reference to fig. 3. When the device 1300 is acting as a terminal device 110, the controller 1310 and the transceiver 1340 can cooperate to implement the methods described above with reference to fig. 1-7. For example, in some embodiments, all actions described above relating to data/information transceiving may be performed by the transceiver 1340, while other actions may be performed by the controller 1310. All of the features described above with reference to fig. 2-7 apply to the apparatus 1300 and are not described in detail herein.

In general, the various example embodiments of this 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. While aspects of embodiments of the disclosure have been illustrated or 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, embodiments of the disclosure may be described in the context of machine-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor. 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 embodiments, the functionality of the program modules may be combined or divided between program modules as described. Machine-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 machine-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 machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-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 describing particular embodiments that may be directed to particular inventions. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments 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 communication method implemented at a terminal device, comprising:

receiving, from a network device, a first request for channel state information, CSI, for a channel between the network device and the terminal device in a third subframe, the first request indicating a first CSI process group associated with the CSI, CSI processes in the first CSI process group having indices; and

in response to the number of CSI processes in the first CSI process group being above the number of available CSI processes,

determining a subgroup of the first CSI process group, the subgroup comprising CSI processes with high indices in the first CSI process group, and a number of CSI processes in the subgroup being a difference between the number of CSI processes in the first CSI process group and the number of available CSI processes; and

determining whether to report CSI for at least one CSI process in the subgroup within a threshold time, comprising:

in a fourth subframe after the third subframe, determining whether to process the at least one CSI process in the subgroup in response to determining that an uplink grant from the network device exists.

2. The method of claim 1, further comprising:

in the third subframe, storing the CSI processes in the subgroup in an ordered list in an order in which a CSI process with the high index precedes and a CSI process with a low index succeeds.

3. The method of claim 1, wherein determining whether to process the at least one CSI process in the subgroup comprises:

in response to receiving a second request for CSI for the channel from the network device in the fourth subframe, the second request indicating a second CSI process group associated with the CSI, CSI processes of the second CSI process group having indices,

storing the CSI processes in the second CSI process group in an ordered list in an order that the CSI process with the high index precedes and the CSI process with the low index succeeds; and

determining to process the at least one CSI process in the subgroup in response to the number of the CSI processes in the second CSI process group being less than the number of the available CSI processes.

4. The method of claim 3, wherein processing the at least one CSI process in the subgroup comprises:

obtaining the CSI processes in the second CSI process group and the at least one CSI process in the sub-group from the ordered list in an order of CSI processes that are placed in the ordered list after being preferentially obtained according to the number of available CSI processes; and

removing the obtained CSI process from the ordered list.

5. The method of claim 1, wherein determining whether to process the at least one CSI process in the subgroup comprises:

in response to not receiving a second request for CSI for the channel from the network device in the fourth subframe, acquiring the at least one CSI process in the subgroup from an ordered list in an order of CSI processes placed in the ordered list after being preferentially acquired according to the number of available CSI processes; and

removing the obtained CSI process from the ordered list.

6. The method of claim 2 or 3, further comprising:

determining a latency of the CSI processes stored in the ordered list; and

discarding one of the CSI processes in response to the latency of the one of the CSI processes being above the threshold time.

7. The method of claim 3 or 5, further comprising:

receiving, from the network device, a third request for CSI for the channel in a fifth subframe after the fourth subframe, the third request indicating a third CSI process group associated with the CSI;

in response to the number of CSI processes in the third CSI process group being greater than the number of available CSI processes,

determining that the at least one CSI process in the subgroup is being processed; and

terminating processing of the at least one CSI process in the subgroup according to a difference between the number of CSI processes in the third CSI process group and the number of available CSI processes.

8. The method of claim 2, wherein ones of the CSI processes in the subgroup that have a low index are configured with aperiodic reference signals.

9. The method of claim 2, wherein a CSI process with a high index of the CSI processes in the subgroup is configured with periodic reference signals.

10. The method of claim 1, wherein the first request further indicates reference signal resources for determining the CSI.

11. The method of claim 10, further comprising:

determining a delay budget based on a comparison of the number of reference signal resources to a second threshold number, the delay budget indicating a location of a sixth subframe relative to the third subframe in which the CSI is to be transmitted to the network device.

12. The method of claim 11, wherein determining the delay budget comprises:

determining an offset based on a comparison of the number of the reference signal resources to the second threshold number; and

increasing a reference delay budget by the offset to obtain the delay budget.

13. The method of claim 12, wherein determining the offset comprises:

increasing the offset by a first predetermined amount in response to the number of the reference signal resources being greater than the second threshold number.

14. The method of claim 13, wherein determining the offset comprises:

increasing the offset by a second predetermined amount, the second predetermined amount being the same or different than the first predetermined amount, in response to the first request being received on a given downlink control channel.

15. A terminal device, comprising:

a transceiver configured to receive, from a network device, a first request for channel state information, CSI, for a channel between the network device and the terminal device in a third subframe, the first request indicating a first CSI process group associated with the CSI, CSI processes of the first CSI process group having indices; and

a controller coupled to the transceiver and configured to respond to the number of CSI processes in the first CSI process group being above the number of available CSI processes,

16. The terminal device of claim 15, wherein the controller is further configured to:

17. The terminal device of claim 15, wherein the controller is further configured to:

18. The terminal device of claim 17, wherein the controller is further configured to:

removing the obtained CSI process from the ordered list.

19. The terminal device of claim 15, wherein the controller is further configured to:

removing the obtained CSI process from the ordered list.

20. The terminal device of claim 16 or 17, wherein the controller is further configured to:

determining a latency of the CSI processes stored in the ordered list; and

21. The terminal device of claim 17 or 19, wherein the controller is further configured to:

22. The terminal device of claim 16, wherein ones of the CSI processes in the subgroup that have a low index are configured with aperiodic reference signals.

23. The terminal device of claim 16, wherein a CSI process with a high index of the CSI processes in the subgroup is configured with periodic reference signals.

24. The terminal device of claim 15, wherein the first request further indicates reference signal resources for determining the CSI.

25. The terminal device of claim 24, wherein the controller is further configured to:

26. The terminal device of claim 25, wherein the controller is further configured to:

increasing a reference delay budget by the offset to obtain the delay budget.

27. The terminal device of claim 26, wherein the controller is further configured to:

28. The terminal device of claim 27, wherein the controller is further configured to: