WO2020220343A1

WO2020220343A1 - Method for communication, communication device, and computer readable medium

Info

Publication number: WO2020220343A1
Application number: PCT/CN2019/085366
Authority: WO
Inventors: Gang Wang
Original assignee: Nec Corporation
Priority date: 2019-04-30
Filing date: 2019-04-30
Publication date: 2020-11-05

Abstract

Embodiments of the present disclosure provide a solution for sidelink transmission and reception. In a method for communication, a first device determines a target transmission resource pool for reporting channel state information of a sidelink channel between the first device and a second device. The first device determines whether to report the channel state information to the second device. In response to a determination to report the channel state information, the first device reports the channel state information to the second device using a resource from the target transmission resource pool. The embodiments of the present disclosure provide a feasible and reasonable solution for sidelink communications.

Description

METHOD FOR COMMUNICATION, COMMUNICATION DEVICE, AND COMPUTER READABLE MEDIUM

FIELD

Embodiments of the present disclosure generally relate to the field of communication, and in particular, to sidelink transmission and reception.

BACKGROUND

The latest developments of the 3GPP standards are referred to as Long Term Evolution (LTE) of Evolved Packet Core (EPC) network and Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) , also commonly termed as ‘4G. ’ In addition, the term ‘5G New Radio (NR) ’ refers to an evolving communication technology that is expected to support a variety of applications and services. The 5G NR is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (for example, with Internet of Things) , and other requirements. Some aspects of the 5G NR may be based on the 4G Long Term Evolution (LTE) standards.

In recent 3GPP meetings, regarding channel state information (CSI) acquisition for unicast in sidelink physical layer procedures, it is agreed that channel quality indicator (CQI) /rank indicator (RI) reporting is supported, and the CQI and the RI are always reported together. No precoding matrix indicator (PMI) reporting is supported in this work. Multi-rank physical sidelink shared channel (PSSCH) transmission is supported up to two antenna ports. In sidelink, CSI is delivered using PSSCH (including PSSCH containing CSI only) using the resource allocation procedure for data transmission. However, many aspects of the CSI acquisition in sidelink communications are still unclear and indefinite, and thus need to be studied and specified.

SUMMARY

In general, example embodiments of the present disclosure provide a solution for sidelink transmission and reception.

In a first aspect, there is provided a method for communication. The method comprises determining, at a first device, a target transmission resource pool for reporting channel state information of a sidelink channel between the first device and a second device. The method also comprises determining whether to report the channel state information to the second device. The method further comprises in response to a determination to report the channel state information, reporting the channel state information to the second device using a resource from the target transmission resource pool.

In a second aspect, there is provided a communication device. The communication device comprises a processor and a memory storing instructions. The memory and the instructions are configured, with the processor, to cause the communication device to determine a target transmission resource pool for reporting channel state information of a sidelink channel between the communication device and a further communication device. The memory and the instructions are also configured, with the processor, to cause the communication device to determine whether to report the channel state information to the further communication device. The memory and the instructions are further configured, with the processor, to cause the communication device to, in response to a determination to report the channel state information, report the channel state information to the further communication device using a resource from the target transmission resource pool.

In a third aspect, there is provided a computer readable medium having instructions stored thereon. The instructions, when executed on at least one processor of a device, cause the device to carry out the method according to the first aspect.

It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Through the more detailed description of some embodiments of the present disclosure in the accompanying drawings, the above and other objects, features and advantages of the present disclosure will become more apparent, wherein:

Fig. 1 is a schematic diagram of a communication environment in which some embodiments of the present disclosure can be implemented;

Fig. 2 shows a flowchart of an example method in accordance with some embodiments of the present disclosure;

Fig. 3 shows an example communication process among the first device, the second device and the third device in accordance with some embodiments of the present disclosure;

Fig. 4 shows another example communication process among the first device, the second device and the third device in accordance with some embodiments of the present disclosure;

Fig. 5 shows example fields of a MAC CE carried in data transmitted from the first device to the second device in accordance with some embodiments of the present disclosure; and

Fig. 6 is a simplified block diagram of a device that is suitable for implementing some embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar elements.

DETAILED DESCRIPTION OF EMBODIMENTS

Principles of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitations as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

As used herein, the term “network device” or “base station” (BS) refers to a device which is capable of providing or hosting a cell or coverage where terminal devices can communicate. Examples of a network device include, but not limited to, a Node B (NodeB or NB) , an Evolved NodeB (eNodeB or eNB) , a next generation NodeB (gNB) , an infrastructure device for a V2X (vehicle-to-everything) communication, a Transmission/Reception Point (TRP) , a Remote Radio Unit (RRU) , a radio head (RH) , a remote radio head (RRH) , a low power node such as a femto node, a pico node, and the like.

As used herein, the term “terminal device” refers to any device having wireless or wired communication capabilities. Examples of the terminal device include, but not limited to, user equipment (UE) , vehicle-mounted terminal devices, devices of pedestrians, roadside units, personal computers, desktops, mobile phones, cellular phones, smart phones, personal digital assistants (PDAs) , portable computers, image capture devices such as digital cameras, gaming devices, music storage and playback appliances, or Internet appliances enabling wireless or wired Internet access and browsing and the like. For the purpose of discussion, in the following, some embodiments will be described with reference to UEs as examples of terminal devices and the terms “terminal device” and “user equipment” (UE) may be used interchangeably in the context of the present disclosure.

As used herein, the singular forms “a” , “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term “includes” and its variants are to be read as open terms that mean “includes, but is not limited to. ” The term “based on” is to be read as “based at least in part on. ” The term “one embodiment” and “an embodiment” are to be read as “at least one embodiment. ” The term “another embodiment” is to be read as “at least one other embodiment. ” The terms “first, ” “second, ” and the like may refer to different or same objects. Other definitions, explicit and implicit, may be included below.

In some examples, values, procedures, or apparatus are referred to as “best, ” “lowest, ” “highest, ” “minimum, ” “maximum, ” or the like. It will be appreciated that such descriptions are intended to indicate that a selection among many used functional alternatives can be made, and such selections need not be better, smaller, higher, or otherwise preferable to other selections.

Fig. 1 is a schematic diagram of a communication environment 100 in which some embodiments of the present disclosure can be implemented. As shown in Fig. 1, a first device 110 and a second device 120 are in coverage of a third device 130. In other words, the third device 130 may serve the first device 110 and the second device 120, and can provide wireless connections for the first device 110 and the second device 120. In particular, the first device 110 may communicate with the third device 130 via a communication channel such as a wireless communication channel 115, and the second device 120 may communicate with the third device 130 via a communication channel such as a wireless communication channel 125. However, it is appreciated that one or both of the first device 110 and the second device 120 may move to be out of the coverage of the third device 130.

For transmissions from the third device 130 to the first device 110 or the second device 120, the

communication channel

115 or 125 may be referred to as a downlink channel, whereas for transmissions from the first device 110 or the second device 120 to the third device 130, the

communication channel

115 or 125 may alternatively be referred to as an uplink channel. Additionally, the first device 110 may communicate with the second device 120 via a device-to-device (D2D) link, which may also be referred to as a sidelink.

In an example scenario, the second device 120 may transmit data, such as unicast data, groupcast data or broadcast data, via a sidelink channel 135 to the first device 110. For the sidelink channel 135, the first device 110 may perform a channel measurement, for example, through a reference signal transmitted from the second device 120 to the first device 110. Then, the first device 110 may report the CSI of the sidelink channel 135 to the second device 120 through a CSI report (or a CSI feedback) of the sidelink channel 135 via a sidelink channel 145. In such an example scenario, the second device 120 transmitting the data may also be referred to as a source device, and the first device 110 transmitting the CSI feedback may also be referred to as a destination device.

In some embodiments, the first and

second devices

110 and 120 may be terminal devices, and the third device 130 may be a network device. In some other embodiments, the first, second, and

third devices

110, 120, and 130 may be any other suitable communication devices, which can communicated one another. Embodiments of the present disclosure are not limited to the example scenario of Fig. 1. In this regard, it is noted that the first and

second devices

110 and 120 are schematically depicted as mobile phones in Fig. 1. However, it is understood that this depiction is only for example without suggesting any limitation. In other embodiments, the first and

second devices

110 and 120 may be any other wireless communication devices, for example, vehicle-mounted terminal devices.

In case that the first and

second devices

110 and 120 are vehicle-mounted terminal devices, the communications relate to the first and

second devices

110 and 120 may be referred to as V2X communications. More generally, although not shown in Fig. 1, a V2X communication related to the first or

second devices

110 or 120 may comprise a communication between the first or

second devices

110 or 120 and any other communication device, including but not limited to, an infrastructure device, another vehicle-mounted terminal device, a device of a pedestrian, a roadside unit, or the like. Furtherrnore, although not shown, all the communication links as shown in Fig. 1 may be via one or more relays.

It is to be understood that the number of communication devices as shown in Fig. 1 are only for the purpose of illustration without suggesting any limitations. The communication environment 100 may include any suitable number of communication devices adapted for implementing embodiments of the present disclosure. In addition, it would be appreciated that there may be various wireless communications as well as wireline communications (if needed) among these additional communication devices.

The communications in the communication environment 100 may conform to any suitable standards including, but not limited to, Global System for Mobile Communications (GSM) , Extended Coverage Global System for Mobile Internet of Things (EC-GSM-IoT) , Long Term Evolution (LTE) , LTE-Evolution, LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , Code Division Multiple Access (CDMA) , GSM EDGE Radio Access Network (GERAN) , and the like. Furthermore, the communications may be performed according to any generation communication protocols either currently known or to be developed in the future. Examples of the communication protocols include, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols.

As mentioned above, many aspects of the CSI acquisition in sidelink communications are still unclear and indefinite, and thus need to be studied and specified. In particular, it is unclear which resource pool a communication device is to use for transmitting a CSI feedback. It is also unclear about how to trigger a communication device to transmit a CSI feedback. In addition, if a resource for a CSI feedback is selected by a communication device receiving sidelink data, how the communication device transmitted the sidelink data can know that a data transmission (such as, a PSSCH) from the receiving communication device contains CSI. Further, in unicast or groupcast session mode 1 as specified in 3GPP specifications, it is unclear whether a CSI resource can be assigned by a network device for a communication device receiving sidelink data.

In order to solve the above technical problems and potentially other technical problems in conventional solutions, embodiments of the present disclosure provide a solution for sidelink transmission and reception. In particular, the embodiments of the present disclosure clarify which resource pool a communication device is to use to transmit a CSI feedback, and how to trigger the communication device to transmit the CSI feedback. The embodiments of the present disclosure provide a feasible and reasonable solution for sidelink communications. Principles and implementations of the present disclosure will be described in detail below with reference to the figures.

Fig. 2 shows a flowchart of an example method 200 in accordance with some embodiments of the present disclosure. The method 200 can be implemented at a communication device, such as the first device 110 as shown in Fig. 1. Additionally or alternatively, the method 200 can also be implemented at the second device 120, as well as other communication devices not shown in Fig. 1. For the purpose of discussion, the method 200 will be described with reference to Fig. 1 as performed by the first device 110 without loss of generality.

At block 210, the first device 110 determines a target transmission resource pool for reporting CSI of the sidelink channel 135 between the first device 110 and the second device 120. As used herein, the term “resource” may refer to any resource for performing communications, such as resources in time domain, resources in frequency domain, resources in space domain, resources in code domain, or any other resource enabling a communication, and the like. Accordingly, the term “resource pool” may refer to a set of resource units in time domain, frequency domain, space domain, code domain, and the like. As used herein, the term “CSI” may refer to any information representing a state of a channel, and may include, but not limited to, a CQI, an RI, and any other parameter suitable for indicating a state of a channel, or the like.

As an example, the above determination of the target transmission resource pool by the first device 110 may be performed during or after the establishment of the sidelink channel 135. In the sidelink communications between the first device 110 and the second device 120, for the purpose of improving the sidelink transmissions from the second device 120 to the first device 110, the first device 110 may need to perform a CSI measurement on the sidelink channel 135, and then send a CSI report based on the CSI measurement to the second device 120, such that the second device 120 can adjust various transmission parameters of the sidelink transmissions from the second device 120 to the first device 110 based on the CSI report. In order to transmit the CSI report, the first device 110 may need to first determine the target transmission resource pool for reporting the CSI. Then, if there is a CSI report to transmit, the first device 110 may use a specific resource in the target transmission resource pool for performing the transmission. As described below, there may be various possible options for the first device 110 to determine the target transmission resource pool.

In some embodiments, the first device 110 may select a transmission resource pool of the second device 120 as the target transmission resource pool, which transmission resource pool is used by the second device 120 to transmit sidelink data (such as, unicast or groupcast data) to the first device 110. As such, the second device 120 and the first device 110 can use a same resource pool for transmitting sidelink data and a CSI feedback, respectively, thus avoiding a switch between different resource pools at the second device 120 when transmitting the data to the first device 110 and receiving the CSI feedback from the first device 110. Also, it is noted that in some cases, the transmission resource pool of the second device 120 for transmitting the sidelink data may be part of a reception resource pool of the first device 110.

In these embodiments, in order to select the above transmission resource pool of the second device 120 as the target transmission resource pool, the first device 110 needs to first determine the transmission resource pool. The transmission resource pool may be determined in different manners based on diffident locations of the first device 110. For example, if the first device 110 is in the coverage of the third device 130 serving the second device 120, the first device 110 may receive an indication of the transmission resource pool from the third device 130. This is described below in more detail with reference to Fig. 3.

Fig. 3 shows an example communication process 300 among the first device 110, the second device 120 and the third device 130 in accordance with some embodiments of the present disclosure. As shown, the second device 120 may transmit 305 sidelink data to the first device 110 in the sidelink channel 135. In addition, since the first device 110 is in the coverage of the third device 130, the third device 130 can transmit 310 the indication of the transmission resource pool used by the second device 120 to transmit the sidelink data. Then, the first device 110 may select the transmission resource pool as the target transmission resource pool for reporting CSI of the sidelink channel 135. During the sidelink communications between the first device 110 and the second device 120, the first device 110 may determine 315 to send a CSI feedback to the second device 120.

In order to use a specific resource from the target transmission resource pool to transmit the CSI feedback, the first device 110 may transmit 320 a request for using the resource to the third device 130, since the first device 110 is in the coverage of the third device 130 and can communicate with the third device 130. Then, the first device 110 may receive 325 a grant for using the resource from the third device 130. Upon receiving the grant, the first device 110 can transmit 330 the CSI feedback to the second device 120 using the resource. In this way, the second device 120 can be free of the process of requesting and granting for using the resource, thus reducing the communication burden of the second device 120.

In contrast, if the first device 110 is out of the coverage of the third device 130, the first device 110 may alternatively receive the indication of the transmission resource pool from the second device 120. For example, in case that the unicast or groupcast session between the first device 110 and the second device 120 is mode 1 (the base station scheduled mode) as specified in 3GPP specifications, the second device 120 may need to request a sidelink grant on behalf of the first device 110 from the third device 130 for a CSI feedback of the first device 110, and then forward the sidelink grant to the first device 110. This is described below in more detail with reference to Fig. 4.

Fig. 4 shows another example communication process 400 among the first device 110, the second device 120 and the third device 130 in accordance with some embodiments of the present disclosure. As shown, since the second device 120 knows the transmission resource pool used for transmitting the sidelink data, the second device 120 may transmit 405 an indication of the transmission resource pool to the first device 110. For example, this indication may be transmitted via sidelink RRC signaling during the setup of the data (such as, unicast or groupcast data) session. Then, the first device 110 may select the transmission resource pool as the target transmission resource pool for reporting CSI of the sidelink channel 135. During the sidelink communications between the first device 110 and the second device 120, the first device 110 may determine 410 to send a CSI feedback to the second device 120.

In order to use a specific resource from the target transmission resource pool to transmit the CSI feedback, since the first device 110 is out of the coverage of the third device 130, the first device 110 may transmit 415 a request for using the resource to the second device 120, such that the second device 120 can forward 420 the request to the third device 130. To this end, the second device 120 can transmit a buffer status report (BSR) to the third device 130, if the CSI feedback from the first device 110 is triggered. Then, the third device 130 may transmit 425 a grant for using the resource to the second device 120, so as to forward to the first device 110. Accordingly, the first device 110 may receive 430 the grant from the second device 120. For example, the grant may be conveyed via a media access control (MAC) control element (CE) . Upon receiving the grant, the first device 110 can transmit 435 the CSI feedback to the second device 120 using the resource. In this way, the granting for using the resource can be controlled by the third device 130 in a centralized manner, although the first device 110 cannot communicate with the third device 130 directly.

As another possible option for the first device 110 to determine the target transmission resource pool, the first device 110 may select the target transmission resource pool from its own one or more transmission resource pools configured for reporting CSI of the sidelink channel 135. In other words, the target transmission resource pool can be a transmission resource pool configured or pre-configured for the first device 110. In this option, at least one transmission resource pool of the first device 110 is associated with the sidelink channel 135 (or unicast or groupcast session) for transmitting CSI feedbacks. In this way, the operation of determining the target transmission resource pool at the first device 110 can be simplified.

The one or more associated transmission resource pools are known to both the first and

second devices

110 and 120, and may be determined by the first device 110, by the second device 120, by the third device 130, or through a negotiation between the first device 110 and second device 120. It is noted that in this possible option, if the first device 110 is in the coverage of the third device 130, the target transmission resource pool may be indicated by the third device 130. Alternatively, if the first device 110 is out of the coverage of the third device 130, the target transmission resource pool may be indicated by the second device 120 which can communicate with the third device 130.

As a further possible option for the first device 110 to determine the target transmission resource pool, instead of using a transmission resource pool of the second device 120 or a transmission resource pool of the first device 110, the first device 110 may determine the target transmission resource pool for the sidelink channel 135 based on a predefined association between the sidelink channel 135 and the target transmission resource pool. For example, this predefined association may be a one-to-one mapping from the sidelink channel 135 to the target transmission resource pool. That is, for the sidelink channel 135 (or each unicast or groupcast session) , there is a corresponding transmission resource pool for reporting CSI by the first device 110. In this way, the transmission of the CSI of the sidelink channel 135 can be performed using a dedicated resource pool.

In some embodiments, the dedicated resource pool associated with the sidelink channel 135 can be configured by the third device 130, and the first device 110 can receive signaling from the third device 130 or the second device 120 to determine the configuration of the associated dedicated resource pool. It is noted that in this possible option, if the first device 110 is in the coverage of the third device 130, the target transmission resource pool may be indicated by the third device 130. Alternatively, if the first device 110 is out of the coverage of the third device 130, the target transmission resource pool may be indicated by the second device 120 which can communicate with the third device 130.

Referring back to Fig. 2, at block 220, the first device 110 determines whether to report the CSI of the sidelink channel 135 to the second device 120. There are various manners for the first device 110 to perform this determination. For example, the first device 110 may report the CSI of the sidelink channel 135 periodically, and the periodicity can be configured, for example, by the third device 130. As another example, the second device 120 may trigger the first device 110 to report the CSI of the sidelink channel 135 by sending sidelink control information (SCI) containing a trigger to the first device 110.

However, in some embodiments of the present disclosure, the first device 110 can determine whether to report the CSI of the sidelink channel 135 by itself according to one or more predefined rules. These rules may be based on a comparison between a current value (ameasured value or a value to be reported) representing the CSI of the sidelink channel 135 and at least one previously measured value or at least one value previously reported to the second device 120 representing the CSI of the sidelink channel 135. Additionally or alternatively, these rules may be based on a comparison between the current value (ameasured value or a value to be reported) and a configurable threshold. In this way, different from the periodic manner and the trigger manner, the first device 110 can determine by itself whether to report the CSI of the sidelink channel 135.

For example, the first device 110 may use a first rule based on a comparison between a currently measured value representing the CSI of the sidelink channel 135 and a previously measured value representing the CSI transmitted to the second device 120. In particular, if a difference between the currently measured value and the previously measured value exceeds a configurable threshold, meaning that the channel state of the sidelink channel 135 may have changed significantly, then the first device 110 may determine to report the current CSI of the sidelink channel 135 to the second device 120.

For example, the first device 110 may need to report the CSI to the second device 120, if the calculated CSI have been changed by a configurable threshold comparing to the previously reported CSI. In alternative, the first device 110 may need to report the CSI to the second device 120, if the calculated rank has been changed, for example, from rank 2 to rank 1 or from rank 1 to rank 2. In alternative, the first device 110 may need to report the CSI to the second device 120, if the calculated CQI of at least one layer is greater or less than the previously reported CQI of the same layer by a configurable threshold.

Alternatively or additionally, the first device 110 may use a second rule based on a comparison between a value to be reported representing the CSI of the sidelink channel 135 and a previously reported value representing the CSI of the sidelink channel 135. In some scenarios, in order to report the CSI of the sidelink channel 135 to the second device 120, the first device 110 may map the measured value of the CSI of the sidelink channel 135 to a value to be reported according to a predetermined mapping rule. That is, this mapped value can also represent the CSI, and thus can indicate the channel state of the sidelink channel 135. Then, the first device 110 may send the mapped value to the second device 120, instead of sending the measured value of the CSI of the sidelink channel 135.

Therefore, if a difference between the value to be reported and the previously reported value exceeds a configurable threshold, meaning that the channel state of the sidelink channel 135 may have changed significantly, then the first device 110 may determine to report the current CSI of the sidelink channel 135 to the second device 120. For example, the first device 110 may need to report the CSI to the second device 120, if a value to be reported representing the CSI changed by a configurable threshold comparing to the previously reported value. In alternative, the first device 110 may need to report the CSI to the second device 120, if a value representing the rank to be reported has been changed. In alternative, the first device 110 may need to report the CSI to the second device 120, if a value to be reported, which represents the CQI of at least one layer, is greater or less than the previously reported value, which represents the CQI of the same layer by a configurable threshold.

Alternatively or additionally, the first device 110 may use a third rule based on a comparison between a current value (ameasured value or a value to be reported) representing the CSI of the sidelink channel 135 and a plurality of previous values (previously measured values or previously reported values) representing the CSI of the sidelink channel 135. Particularly, if each of a plurality of differences between the current value and the plurality of previous values exceeds a configurable threshold, meaning that the channel state of the sidelink channel 135 may have changed significantly, then the first device 110 may determine to report the current CSI of the sidelink channel 135 to the second device 120. For example, the first device 110 may need to report the CSI to the second device 120, if the calculated CQIs of a configurable number of previous measurements of at least one layer are all greater or less than the current CQI of the same layer by a configurable threshold. In this way, a potentially useless report of a sudden and transient change in the channel state of the sidelink channel 135 can be avoided.

Alternatively or additionally, the first device 110 may use a fourth rule based on a comparison between a current value (ameasured value or a value to be reported) representing the CSI of the sidelink channel 135 and an average of a plurality of previous values (previously measured values or previously reported values) representing the CSI of the sidelink channel 135. Particularly, if a difference between the current value and an average of the plurality of previous values exceeds a configurable threshold, meaning that the channel state of the sidelink channel 135 may have changed significantly, then the first device 110 may determine to report the current CSI of the sidelink channel 135 to the second device 120. For example, the first device 110 may need to report the CSI to the second device 120, if an averaged CQI of a configurable number of previous measurements of at least one layer is greater or less than the current CQI of the same layer by a configurable threshold. In this way, a potentially useless report of a sudden and transient change in the channel state of the sidelink channel 135 can also be avoided.

Alternatively or additionally, since the reference signal received power (RSRP) in a sidelink (SL-RSRP) can also indicate the channel state of the sidelink, the first device 110 may use a fifth rule based on a comparison between a first RSRP associated with the current channel state of the sidelink channel 135 and a second RSRP associated with a previous channel state of the sidelink channel 135. In particular, the first device 110 can determine the first RSRP associated with the current CSI of the sidelink channel 135, and the second RSRP associated with the previously measured or reported CSI of the sidelink channel 135. If a difference between the first RSRP and the second RSRP exceeds a configurable threshold, the first device 110 may determine to report the current CSI of the sidelink channel 135 to the second device 120. In other words, the first device 110 may need to report the CSI to the second device 120, if the measured SL-RSRP has been changed by a configurable threshold comparing to the SL-RSRP when the previous CSI was reported.

Alternatively or additionally, the first device 110 may use a sixth rule based on a configurable threshold interval between two successively reported values representing the CSI of the sidelink channel 135. In particular, if a duration from previously reporting a first value representing the CSI of the sidelink channel 135 to generating a second value to be reported representing the CSI of the sidelink channel 135 exceeds the configurable threshold duration, meaning that the CSI of the sidelink channel 135 is not reported too frequently, then the first device 110 may determine to report the current CSI of the sidelink channel 135 to the second device 120. For example, the first device 110 can report the CSI in a time slot n (n is an integer) , if the slot n is later than the slot where the previous CSI was reported by a configurable threshold number of slots.

In some embodiments, the configurable threshold duration may be determined based on movement speeds of the first device 110 and second device 120, since a greater movement speed of the first device 110 or the second device 120 may cause a more quick change in the channel state of the sidelink channel 135 between the first device 110 and second device 120. By using this configurable threshold duration, excessively frequent CSI reports from the first device 110 to the second device 120 can be effectively avoided, and thus communication resources of the whole communication system and the processing resources of the first device 110 and second device 120 can be saved.

The sixth rule associated with the configurable threshold interval may be used together with any of other rules as described above. For example, the sixth rule associated with the configurable threshold duration and the second rule associated with the reported value can be used simultaneously. In such a case, the first device 110 can report the CSI to the second device 120 in a time slot n (n is an integer) , if the slot n is later than the slot where the previous CSI was reported by a configurable threshold number of slots, and the value to be reported representing the CSI has been changed by a configurable threshold comparing to the previously reported value representing the CSI. More generally, all the rules as described above can be used in any combination.

At block 230, if the first device 110 determines to report the CSI of the sidelink channel 135 to the second device 120, the first device 110 reports the CSI to the second device 120 using a resource from the target transmission resource pool. In some embodiments, the resource for reporting the CSI can be selected by the first device 110, and the first device 110 may request a grant for using the resource from a network device (for example, the third device 130) . In some other embodiments, the resource can be determined by a network device (for example, the third device 130) , and the network device may inform the first device 110 about the selected resource.

In some embodiments, the resource selected from the target transmission resource pool for the first device 110 to report the CSI to the second device 120 may include a semi-persistently scheduled resource in the target transmission resource pool. In such embodiments, the first device 110 may have a configured (such as, by the third device 130) sidelink grant for transmitting CSI feedbacks. This means that the first device 110 may use a set of semi-persistently scheduled resource units to report the CSI of the sidelink channel 135, when the first device 110 determines that the CSI is to be reported. This set of resource units may be spaced with a constant interval in time domain, such as, 10 milliseconds. In case the first device 110 determines that at least one rule for reporting the CSI as discussed above is satisfied, the first device 110 may use a next resource unit in the set of semi-persistently scheduled resource units.

The first device 110 may employ various transmission channels to report the CSI of the sidelink channel 135. For example, the first device 110 may report the CSI to the second device 120 using a data transmission channel, such as, a PSSCH. In other words, the PSSCH can be used to convey the CSI. In this event, since the PSSCH may carry other data and other CSI reports for other communication devices, the first device 110 may need to cause the second device 120 to know that the CSI in the PSSCH to be transmitted is intended for the second device 120.

To this end, the first device 110 may transmit sidelink control information of the PSSCH carrying the CSI to the second device 120. The sidelink control information contains a first identifier of the first device 110 and a second identifier of the second device 120. As such, upon receiving and decoding the sidelink control information, the second device 120 may know that the PSSCH to be transmitted and associated with the sidelink control information is intended for itself. Then, the first device 110 may transmit the PSSCH carrying the CSI to the second device 120, and the second device 120 can receive the CSI accordingly.

Alternatively or additionally, the sidelink control information may be scrambled by an identifier known to the second device 120, for example, a SCI-Radio Network Temporary Identifier (RNTI) of the second device 120. As such, upon receiving and decoding the sidelink control information, the second device 120 can also know that the PSSCH to be transmitted and associated with the sidelink control information is intended for itself. It is noted that the PSSCH may be transmitted in a unicast or groupcast manner, so as to facilitate the transmission of the CSI via the PSSCH from the first device 110 to the second device 120. However, it is also feasible for the first device 110 to transmit the PSSCH in a broadcast manner, since the second device 120 may also be able to receive and decode a broadcast PSSCH.

Alternatively, the first device 110 may use a data transmission channel to transmit the CSI report along with the first identifier of the first device 110 and the second identifier of the second device 120. For example, the first device 110 may transmit a PSSCH to the second device 120, which can carry the CSI of the sidelink channel 135, the first identifier, and the second identifier. It is noted that first device 110 may intend to transmit the PSSCH to one or more communication devices other than the second device 120. However, since the PSSCH contains the first identifier and the second identifier, the second device 120 can know that the CSI contained in this PSSCH is intended for itself when receiving the PSSCH, although other data or information carried in the PSSCH is intended for other communication devices.

It is also noted that the PSSCH may be transmitted in a broadcast manner, so as to facilitate the receiving of the PSSCH by the second device 120. However, it is also feasible for the first device 110 to transmit the PSSCH in a unicast or groupcast manner, since the second device 120 may also be able to receive and decode a unicast or groupcast PSSCH. In some embodiments, the CSI, the first identifier, and the second identifier may be contained in a MAC CE, which is described below in detail with reference to Fig. 5.

Fig. 5 shows example fields of a MAC CE 500 carried in data transmitted from the first device 110 to the second device 120 in accordance with some embodiments of the present disclosure. As shown, the MAC CE 500 carried in the transmitted data (for example, a PSSCH) may include a first field 510, a second filed 520, and a third field 530. The first field 510 can carry the first identifier of the first device 110, the second field 520 can carry the second identifier of the second device 120, and the third field 530 can carry the CSI, which may include measured CQI or RI, for example.

Fig. 6 is a simplified block diagram of a device 600 that is suitable for implementing some embodiments of the present disclosure. The device 600 can be considered as a further example embodiment of the first device 110, the second device 120, and third device 130 as shown in Fig. 1. Accordingly, the device 600 can be implemented at or as at least a part of the first device 110, the second device 120, and third device 130.

As shown, the device 600 includes a processor 610, a memory 620 coupled to the processor 610, a suitable transmitter (TX) and receiver (RX) 640 coupled to the processor 610, and a communication interface coupled to the TX/RX 640. The memory 620 stores at least a part of a program 630. The TX/RX 640 is for bidirectional communications. The TX/RX 640 has at least one antenna to facilitate communication, though in practice an Access Node mentioned in this application may have several ones. The communication interface may represent any interface that is necessary for communication with other network elements, such as X2 interface for bidirectional communications between gNBs or eNBs, S1 interface for communication between a Mobility Management Entity (MME) /Serving Gateway (S-GW) and the gNB or eNB, Un interface for communication between the gNB or eNB and a relay node (RN) , or Uu interface for communication between the gNB or eNB and a terminal device.

The program 630 is assumed to include program instructions that, when executed by the associated processor 610, enable the device 600 to operate in accordance with the embodiments of the present disclosure, as discussed herein with reference to Fig. 2. The embodiments herein may be implemented by computer software executable by the processor 610 of the device 600, or by hardware, or by a combination of software and hardware. The processor 610 may be configured to implement various embodiments of the present disclosure. Furthermore, a combination of the processor 610 and memory 620 may form processing means 650 adapted to implement various embodiments of the present disclosure.

The memory 620 may be of any type suitable to the local technical network and may be implemented using any suitable data storage technology, such as a non-transitory computer readable storage medium, semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. While only one memory 620 is shown in the device 600, there may be several physically distinct memory modules in the device 600. The processor 610 may be of any type suitable to the local technical network, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 600 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

The components included in the apparatuses and/or devices of the present disclosure may be implemented in various manners, including software, hardware, firmware, or any combination thereof. In one embodiment, one or more units may be implemented using software and/or firmware, for example, machine-executable instructions stored on the storage medium. In addition to or instead of machine-executable instructions, parts or all of the units in the apparatuses and/or devices may be implemented, at least in part, by one or more hardware logic components. For example, and without limitation, illustrative types of hardware logic components that can be used include Field-programmable Gate Arrays (FPGAs) , Application-specific Integrated Circuits (ASICs) , Application-specific Standard Products (ASSPs) , System-on-a-chip systems (SOCs) , Complex Programmable Logic Devices (CPLDs) , and the like.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some 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 various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representation, it will be appreciated 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.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the process or method as described above with reference to any of Fig. 2. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

The above program code may be embodied on a machine readable medium, which may be any tangible medium that may 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 not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the machine readable storage medium would 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 fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Further, 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 certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific embodiment details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in language specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily 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

A method for communication, comprising:

determining, at a first device, a target transmission resource pool for reporting channel state information of a sidelink channel between the first device and a second device;

determining whether to report the channel state information to the second device; and

in response to a determination to report the channel state information, reporting the channel state information to the second device using a resource from the target transmission resource pool.
The method of claim 1, wherein determining the target transmission resource pool comprises:

determining a transmission resource pool used by the second device to transmit data to the first device; and

selecting the transmission resource pool as the target transmission resource pool.
The method of claim 1, wherein determining the target transmission resource pool comprises:

if the first device is in coverage of a third device serving the second device, receiving an indication of the target transmission resource pool from the third device.
The method of claim 3, further comprising:

transmitting, to the third device, a request for using the resource from the target transmission resource pool; and

receiving, from the third device, a grant for using the resource.
The method of claim 1, wherein determining the target transmission resource pool comprises:

if the first device is out of coverage of a third device serving the second device, receiving an indication of the target transmission resource pool from the second device.
The method of claim 5, further comprising:

transmitting, to the second device, a request for using the resource such that the second device forwards the request to the third device; and

receiving, from the second device, a grant for using the resource forwarded from the third device.
The method of claim 1, wherein determining the target transmission resource pool comprises:

selecting the target transmission resource pool from at least one transmission resource pool of the first device configured for reporting the channel state information of the sidelink channel.
The method of claim 1, wherein determining the target transmission resource pool comprises:

determining the target transmission resource pool for the sidelink channel based on a predefined association between the sidelink channel and the target transmission resource pool.
The method of claim 1, wherein determining whether to report the channel state information comprises at least one of:

if a difference between a measured value representing the channel state information and a previously measured value representing the channel state information transmitted to the second device exceeds a first threshold, determining to report the channel state information; and

if a difference between a value to be reported representing the channel state information and a previously reported value representing the channel state information exceeds a second threshold, determining to report the channel state information.
The method of claim 1, wherein determining whether to report the channel state information comprises at least one of:

if each of a plurality of differences between a value to be reported representing the channel state information and a plurality of values previously reported to the second device representing the channel state information exceeds a third threshold, determining to report the channel state information; and

if a difference between the value to be reported representing the channel state information and an average of the plurality of values previously reported to the second device exceeds a fourth threshold, determining to report the channel state information.
The method of claim 1, wherein determining whether to report the channel state information comprises at least one of:

if a difference between received power of a first reference signal for currently rneasuring the channel state information and received power of a second reference signal for previously measuring the channel state information exceeds a five threshold, determining to report the channel state information; and

if a duration from previously reporting a first value representing the channel state information to generating a second value to be reported representing the channel state information exceeds a threshold duration, determining to report the channel state information.
The method of claim 1, wherein reporting the channel state information comprises:

transmitting sidelink control information of a physical sidelink shared channel to the second device, the sidelink control information containing a first identifier of the first device and a second identifier of the second device; and

transmitting the physical sidelink shared channel carrying the channel state information to the second device.
The method of claim l, wherein reporting the channel state information comprises:

transmitting sidelink control information of a physical sidelink shared channel to the second device, the sidelink control information being scrambled by an identifier known to the second device; and

transmitting the physical sidelink shared channel carrying the channel state information to the second device.
The method of claim 1, wherein reporting the channel state information comprises:

transmitting, to the second device, a physical sidelink shared channel carrying the channel state information, a first identifier of the first device, and a second identifier of the second device.
The method of claim 1, wherein the resource includes a semi-persistently scheduled resource in the target transmission resource pool.
A communication device, comprising:

a processor; and

a memory storing instructions,

the memory and the instructions being configured, with the processor, to cause the communication device to:

determine a target transmission resource pool for reporting channel state information of a sidelink channel between the communication device and a further communication device;

determine whether to report the channel state information to the further communication device; and

in response to a determination to report the channel state information, report the channel state information to the further communication device using a resource from the target transmission resource pool.
The communication device of claim 16, wherein the memory and the instructions are further configured, with the processor, to cause the communication device to:

determine a transmission resource pool used by the further communication device to transmit data to the communication device; and

select the transmission resource pool as the target transmission resource pool.
The communication device of claim 16, wherein the memory and the instructions are further configured, with the processor, to cause the communication device to:

if the communication device is in coverage of a network device serving the further communication device, receive an indication of the target transmission resource pool from the network device.
The communication device of claim 18, wherein the memory and the instructions are further configured, with the processor, to cause the communication device to:

transmit, to the network device, a request for using the resource from the target transmission resource pool; and

receive, from the network device, a grant for using the resource.
The communication device of claim 16, wherein the memory and the instructions are further configured, with the processor, to cause the communication device to:

if the communication device is out of coverage of a network device serving the further communication device, receive an indication of the target transmission resource pool from the further communication device.
The communication device of claim 20, wherein the memory and the instructions are further configured, with the processor, to cause the communication device to:

transmit, to the further communication device, a request for using the resource such that the further communication device forwards the request to the network device; and

receive, from the further communication device, a grant for using the resource forwarded from the network device.
The communication device of claim 16, wherein the memory and the instructions are further configured, with the processor, to cause the communication device to:

select the target transmission resource pool from at least one transmission resource pool of the communication device configured for reporting the channel state information of the sidelink channel.
The commnnication device of claim 1, wherein the memory and the instructions are further configured, with the processor, to cause the cormmunication device to:

determine the target transmission resource pool for the sidelink channel based on a predefined association between the sidelink channel and the target transmission resource pool.
The communication device of claim 16, wherein the memory and the instructions are further configured, with the processor, to cause the communication device to at least one of:

if a difference between a measured value representing the channel state information and a previously measured value representing the channel state information transmitted to the second device exceeds a first threshold, determine to report the charmel state information; and

if a difference between a value to be reported representing the channel state information and a previously reported value representing the channel state information exceeds a second threshold, determine to report the channel state information.
The communication device of claim 16, wherein the memory and the instructions are further configured, with the processor, to cause the communication device to at least one of:

if each of a plurality of differences between a value to be reported representing the channel state information and a plurality of values previously reported to the second device representing the channel state information exceeds a third threshold, determine to report the channel state information; and

if a difference between the value to be reported representing the channel state information and an average of the plurality of values previously reported to the second device exceeds a fourth threshold, determine to report the channel state information.
The communication device of claim 16, wherein the memory and the instructions are further configured, with the processor, to cause the communication device to at least one of:

if a difference between received power of a first reference signal for currently measuring the channel state information and received power of a second reference signal for previously measuring the channel state information exceeds a five threshold, determine to report the channel state information; and

if a duration from previously reporting a first value representing the channel state information to generating a second value to be reported representing the channel state information exceeds a threshold duration, determine to report the channel state information.
The communication device of claim 16, wherein the memory and the instructions are further configured, with the processor, to cause the communication device to:

transmit sidelink control information of a physical sidelink shared channel to the further communication device, the sidelink control information containing a first identifier of the communication device and a second identifier of the further communication device; and

transmit the physical sidelink shared channel carrying the channel state information to the further communication device.
The communication device of claim 16, wherein the memory and the instructions are further configured, with the processor, to cause the communication device to:

transmit sidelink control information of a physical sidelink shared channel to the further communication device, the sidelink control information being scrambled by an identifier known to the further communication device; and

transmit the physical sidelink shared channel carrying the channel state information to the further communication device.
The communication device of claim 16, wherein the memory and the instructions are further configured, with the processor, to cause the communication device to:

transmit, to the further communication device, a physical sidelink shared channel carrying the channel state information, a first identifier of the communication device, and a second identifier of the further communication device.
The communication device of claim 16, wherein the resource includes a semi-persistently scheduled resource in the target transmission resource pool.
A computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor of a device, causing the device to carry out the method according to any of claims 1 to 15.