CN113258972A

CN113258972A - Channel state information feedback and receiving method, device and medium of straight-through link

Info

Publication number: CN113258972A
Application number: CN202010090118.3A
Authority: CN
Inventors: 郑石磊; 赵锐
Original assignee: Datang Mobile Communications Equipment Co Ltd
Current assignee: Datang Mobile Communications Equipment Co Ltd
Priority date: 2020-02-13
Filing date: 2020-02-13
Publication date: 2021-08-13
Anticipated expiration: 2040-02-13
Also published as: CN113258972B

Abstract

The invention discloses a method, a device and a medium for feeding back and receiving channel state information of a direct link, comprising the following steps: and when the first terminal feeding back the channel state information feeds back the channel state information, the first terminal sends the channel state information according to the rule appointed by the second terminal receiving the channel state information. And when receiving the channel state information sent by the first terminal, the second terminal receives the channel state information fed back by the first terminal according to an agreed rule. By adopting the invention, the size of the transmission block is not much larger than the channel state information to be sent by the actual media access control layer, thereby not wasting the frequency spectrum efficiency.

Description

Channel state information feedback and receiving method, device and medium of straight-through link

Technical Field

The present invention relates to the field of wireless communication technologies, and in particular, to a method, an apparatus, and a medium for feeding back and receiving channel state information of a direct link.

Background

Because a mechanism for feeding back CSI (channel state information) is introduced into a unicast communication mode in NR V2X (New air interface Vehicle networking technology; NR: New Radio; V2X: Vehicle networking technology, channel-to-evolution), the mechanism is used for adjusting the sending state of a sending end to adapt to a channel to achieve higher communication quality. Currently, the 3GPP conference has agreed to place CSI in a MAC CE (Media Access Control-Control element), and transmit the CSI through a physical downlink shared channel (psch) bearer. The TBS (transport block size) of the current data channel is determined by a corresponding MCS (Modulation and Coding Scheme) table and SCI (scheduling control information).

The prior art is not enough: the existing CSI feedback mechanism has the problems of information bit waste and incapability of bringing coding gain.

Disclosure of Invention

The invention provides a method, a device and a medium for feeding back and receiving channel state information of sidelink, which are used for solving the problem that information bits are wasted in the existing mechanism for feeding back CSI.

The embodiment of the invention provides a CSI feedback method of a direct link, which comprises the following steps:

when feeding back CSI, a first terminal feeding back CSI sends the CSI according to a rule agreed with a second terminal receiving the CSI, wherein the agreed rule comprises one or the combination of the following modes:

whether the first terminal only carries CSI without data is identified in the SCI, and when the first terminal only carries the CSI without data, the TBS for sending the CSI is determined according to a low-spectral efficiency64QAM MCS table; or the like, or, alternatively,

identifying whether the first terminal only carries CSI without data in the SCI, and taking a preset TBS as a TBS for sending the CSI when the first terminal only carries the CSI without data; or the like, or, alternatively,

the first terminal selects an MCS Table, the MCS Table used by the first terminal is identified in the SCI, and the first terminal determines the TBS for sending the information by using the MCS Table; or the like, or, alternatively,

padding bits in the MAC layer according to an agreed padding mechanism to ensure that the total bit number is equal to the TBS of the transmission information determined according to the MCS table.

In implementation, whether the first terminal only carries CSI without data is identified by introducing an information field of 1bit into SCI.

In implementation, the MCS table used by the first terminal is identified by introducing a 2bits information field in the SCI.

In implementation, padding bits are filled by circularly mapping MAC CE information at the MAC layer until the number of spare bits is filled.

The embodiment of the invention provides a CSI receiving method of a direct link, which comprises the following steps:

when receiving the CSI sent by the first terminal, the second terminal receives the CSI fed back by the first terminal according to an agreed rule, wherein the agreed rule comprises one or the combination of the following modes:

determining whether the first terminal only carries CSI without data according to the identification in the SCI, and determining a TBS for receiving the CSI according to a low-spectral efficiency64QAM MCS table when the identification indicates that the first terminal only carries the CSI without data; or the like, or, alternatively,

determining whether the first terminal only carries CSI without data according to the identification in the SCI, and taking a preset TBS as a TBS for receiving the CSI when the identification indicates that the first terminal only carries the CSI without data; or the like, or, alternatively,

determining an MCS table used by the first terminal according to the identifier in the SCI, and determining a TBS (transport block size) for receiving information according to the MCS table; or the like, or, alternatively,

and after determining the TBS of the received information according to the MCS table, decoding padding bits according to an agreed padding mechanism at the MAC layer.

In practice, the used MCS Table is identified by introducing a 2-bits information field into the SCI.

An embodiment of the present invention provides a first terminal, including: a processor, a memory, and a transceiver, wherein:

a processor for reading the program in the memory, performing the following processes:

padding bits according to an agreed padding mechanism at an MAC layer to ensure that the total bit number is equal to the TBS of the transmitted information determined according to the MCS table;

a transceiver for receiving and transmitting data under the control of the processor.

The embodiment of the invention provides a second terminal, which comprises: a processor, a memory, and a transceiver, wherein:

when receiving the CSI sent by the first terminal, receiving the CSI fed back by the first terminal according to an agreed rule, wherein the agreed rule includes one of the following modes or a combination thereof:

after determining TBS of received information according to MCS table, decoding padded padding bits according to an agreed padding mechanism at MAC layer;

The embodiment of the invention provides a CSI feedback device of a direct link, which comprises:

a sending module, configured to send CSI according to a rule agreed with a second terminal receiving CSI when a first terminal feeding back CSI feeds back CSI, where the agreed rule includes one or a combination of the following manners:

whether the first terminal only bears CSI and has no data is identified in the scheduling control information SCI, and when the first terminal only bears the CSI and has no data, the size TBS of a transmission block for sending the CSI is determined according to a low-spectral efficiency quadrature amplitude modulation 64QAM modulation coding mode table low-spectral efficiency quadrature amplitude modulation 64QAM MCS table; or the like, or, alternatively,

selecting an MCS Table, identifying the MCS Table used by the first terminal in the SCI, and determining the TBS for sending the information by using the MCS Table; or the like, or, alternatively,

padding bits according to an agreed padding mechanism at a Media Access Control (MAC) layer to ensure that the total bit number is equal to the TBS for determining the sending information according to the MCS table.

The embodiment of the invention provides a CSI receiving device of a direct link, which comprises:

a receiving module, configured to receive CSI fed back by a first terminal according to an agreed rule when receiving CSI sent by the first terminal, where the agreed rule includes one or a combination of the following manners:

An embodiment of the present invention provides a computer-readable storage medium storing a computer program for executing the CSI feedback method and/or the CSI receiving method.

The invention has the following beneficial effects:

in the technical solution provided in the embodiment of the present invention, after it is determined that a data channel only carries CSI without data, a low-spectral efficiency64QAM MCS table is used to determine a TBS for receiving information, or a preset TBS is directly used as a TBS for transmitting information, or padding bits are filled in an MAC layer according to an agreed padding mechanism, so that the TBS is not much larger than CSI to be transmitted by an actual MAC layer, and spectrum efficiency is not wasted.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 is a schematic diagram of a data channel structure for carrying data and CSI according to an embodiment of the present invention;

fig. 2 is a schematic flow chart illustrating an implementation of a CSI feedback method for a direct link at a transmitting end according to an embodiment of the present invention;

fig. 3 is a schematic diagram illustrating an implementation flow of a CSI receiving method for a through link at a receiving end according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a first terminal according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a CSI feedback apparatus of a direct link according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of a second terminal in the embodiment of the present invention;

fig. 7 is a schematic structural diagram of a CSI receiving apparatus of a direct link according to an embodiment of the present invention.

Detailed Description

The inventor notices in the process of invention that:

for the case that the data channel only carries CSI, since the number of information bits at this time is small, if the preconfigured MCS table is directly used, more padding bits (padding) may be needed, which wastes information bits and cannot bring coding gain.

The following is a detailed description.

The current TBS determination (TBS determination) scheme is:

1) firstly, an MCS Table used for current transmission is selected according to a high-level parameter MCS _ Table _ SL in resource pool configuration.

2) The terminal determines the modulation mode and the target code rate used by the data channel according to the MCS instruction field in the 1st stage SCI and the MCS table currently used.

3) The actual TBS used is calculated according to the TBS determination requirements.

Fig. 1 is a schematic diagram of a data channel structure for carrying data and CSI, and the structure of a normal data channel is as shown in fig. 1 when the normal data channel carries both data and CSI.

The SL-SCH is a direct link shared channel (sidelink) Data channel (SDU), the PDU is a Protocol Data Unit (Protocol Data Unit), the SDU is a service Data Unit (service Data Unit), R represents a Reserved bit (Reserved bit), F represents a Format bit (Format bit), the LCID is a logical channel identifier (logical channel ID), and L is a length (length) representing the length of the MAC (Media Access Control ) SDU.

However, when the data channel only carries CSI without data, there is no data portion in fig. 1, and only SL-SCH sub header + R/LCID sub header + MAC CE + padding (padding bits). The information ratio at this time is about a maximum: (SL-SCH sub-header is currently undetermined and there are two possible 24 or 32 bits):

24or32+8+8+padding＝40or48+padding(bits)

in this case, only the frequency domain resource of the minimum subchannel needs to be occupied for transmission. At this time, only in the low-spectral efficiency64QAM MCS table (low-frequency spectrum efficiency64QAM MCS table; QAM: Quadrature Amplitude Modulation, Quadrature Amplitude Modulation) can select a proper MCS level; for the other two MCS tables, even if the lowest MCS level is selected, a large amount of padding bits needs to be supplemented, which wastes spectrum efficiency, and furthermore, since the padding process is to fill "0", no coding gain is brought.

The defects of the prior art are as follows:

currently, NR sidelink (new air interface direct link) still uses 3 MCS tables of Uu port, and each resource pool is configured with at least one MCS table. For the CSI-only (data channel only carries CSI), only the low-spectral efficiency64QAM MCS table may work normally in the actual communication process, but there is a possibility that the table is not configured at all when the resource pool is configured, and the terminal at this time cannot use the table, but only uses the configured MCS table. Therefore, the terminal can only use other tables, and among the tables, even if the lowest level MCS is selected, the calculated TBS is still much larger than the CSI to be transmitted by the actual MAC layer, so that the calculated TBS can only be reached by complementing "0", which not only does not bring any coding gain, but also wastes a large amount of spectrum efficiency.

Based on this, in the embodiment of the present invention, a mechanism for sending CSI-only by using a fixed TBS or configuring a suitable TBS by adjusting an MCS table is provided, so as to avoid resource waste and improve the performance of the overall feedback by a certain coding gain.

The following describes embodiments of the present invention with reference to the drawings.

In the description process, the implementation from the transmitting end (first terminal) and the receiving end (second terminal) side will be described, and then an example of the implementation of the two will be given to better understand the implementation of the scheme given in the embodiment of the present invention. Such an explanation does not mean that the two terminals must be implemented in cooperation or separately, and actually, when the transmitting terminal (first terminal) and the receiving terminal (second terminal) are implemented separately, the problems on one side are solved separately, and when the two terminals are used in combination, a better technical effect is obtained.

Fig. 2 is a schematic diagram of an implementation flow of a CSI feedback method for a direct link at a transmitting end, where as shown in the figure, the implementation flow may include:

step 201, determining CSI needing to be fed back;

step 202, when feeding back the CSI, the first terminal feeding back the CSI sends the CSI according to the rule agreed with the second terminal receiving the CSI.

Fig. 3 is a schematic flow chart of an implementation process of a CSI receiving method for a through link at a receiving end, as shown in the figure, the method may include:

step 301, when receiving the CSI sent by the first terminal, the second terminal receives the CSI fed back by the first terminal according to an agreed rule;

and step 302, the second terminal determines the CSI fed back by the first terminal.

In specific implementation, the corresponding TBS calculation may be performed by displaying and indicating a CSI-only (that is, only carrying CSI without data bearer) sending status through an SCI or displaying and indicating selection of an MCS Table by a terminal through the SCI. Or the padding mechanism is implicitly agreed, special processing for MCS Table selection and TBS calculation is not needed.

That is, in implementation, at the transmitting end:

the agreed rules may include one or a combination of the following:

the first terminal selects an MCS table, determines TBS of the transmitted information according to the MCS table, and identifies the used MCS table in the SCI; or the like, or, alternatively,

Correspondingly, on the receiving end, the following are:

the agreed rule comprises one or a combination of the following modes:

and after determining the TBS of the received information according to the MCS table, decoding the padded padding bits according to an agreed padding mechanism at the MAC layer.

The following description will be made separately.

The first scheme is as follows:

under the scheme, the method comprises the following steps:

A. whether the first terminal only carries CSI without data is identified in the SCI, and when the first terminal only carries the CSI without data, the TBS for sending the CSI is determined according to a low-spectral efficiency64QAM MCS table; or the like, or, alternatively,

B. identifying whether the first terminal only carries CSI without data in the SCI, and taking a preset TBS as a TBS for sending the CSI when the first terminal only carries the CSI without data;

in specific implementation, whether the first terminal only carries CSI without data is identified by introducing an information field of 1bit into SCI.

The SCI may be that of a 1st stage SCI, or may be identified in other SCIs, for example: SCI in 2st stage SCI.

A sending end:

1) aiming at the condition of CSI-only (at the moment, a data channel sent by the terminal only carries CSI, and no service data), a 1-bit information domain is introduced into the SCI and is used for indicating whether the first terminal is in a CSI-only state or not.

2) If the first terminal is not in the CSI-only state, directly executing the TBS determination process specified by the prior art; if the first terminal is in the CSI-only state, there are two TBS determination processing schemes:

A. at this time, no matter whether the resource pool used by the first terminal is configured with a low-spectral efficiency64QAM MCS table, the first terminal is forced to use the MCS table to perform a TBS determination process and calculate the TBS. Specifically, the low-spectral efficiency64QAM MCS table can at least adopt the specification of 3GPP protocol 5.1.3.1-3, and the implementation of the low-spectral efficiency64QAM MCS table related to other parts in the embodiment of the present invention can be implemented according to the specification.

B. The first terminal directly uses the pre-configured specific TBS, and the scheme can directly configure the specific TBS according to the total bit number actually contained in the MAC layer by the CSI-only and does not depend on the MCS table to calculate the TBS.

Receiving end:

1) after receiving a transmission block sent by a first terminal, a second terminal firstly judges whether the first terminal is in a CSI-only state according to a corresponding 1bit information domain in a received SCI;

2) if the first terminal is not in the CSI-only state, the second terminal directly executes the TBS determination process specified in the prior art; if the first terminal is in the CSI-only state, the second terminal has two TBS determination schemes in common:

A. at this time, no matter whether the resource pool used by the second terminal is configured with a low-spectral efficiency64QAM MCS table, the second terminal is forced to use the MCS table to perform a TBS determination process and calculate the TBS.

B. The second terminal directly uses the pre-configured specific TBS, and the scheme can directly configure the specific TBS according to the total bit number actually contained in the MAC layer by the CSI-only and does not depend on the MCS table to calculate the TBS.

The following is an example.

Example 1

This embodiment is mainly directed to scheme one a: and when the identification indicates that the first terminal only carries the CSI and has no data, determining the TBS for sending the CSI according to a low-spectral efficiency64QAM MCS table.

A sending end:

2) The first terminal is in a CSI-only state, and at this time, no matter whether a resource pool used by the first terminal is configured with a low-spectral efficiency64QAM MCS table or not, the first terminal is forced to use the MCS table to perform a TBS determination process, and the TBS is calculated.

Receiving end:

1) after receiving the first terminal transmission block, the second terminal firstly judges whether the first terminal is in a CSI-only state according to a corresponding 1bit information domain in the received SCI;

2) and judging that the first terminal is in a CSI-only state, and at the moment, forcing the second terminal to use a low-spectral efficiency64QAM MCS table 5.1.3.1-3 no matter whether the resource pool used by the second terminal is configured with the MCS table, and performing TBS determination process to calculate the TBS.

Example 2

This embodiment is primarily directed to scheme one B: identifying whether the first terminal only carries CSI without data in the SCI, and taking a preset TBS as a TBS for sending the CSI when the first terminal only carries the CSI without data;

a sending end:

2) The first terminal is in a CSI-only state, and the first terminal directly transmits using a pre-configured specific TBS.

Receiving end:

2) and determining that the first terminal is in the CSI-only state, and directly receiving by the second terminal by using the pre-configured specific TBS.

Example 3:

the embodiment mainly aims at the first scheme, and the terminal is in a non-CSI-only state:

a sending end:

2) If the first terminal is not in a CSI-only state, directly executing the TBS determination process specified by the original protocol;

receiving end:

2) if the first terminal is judged not to be in the CSI-only state, the second terminal directly executes the TBS determination process specified by the original protocol;

scheme II:

in the scheme, the first terminal selects the MCS Table, the MCS Table used by the first terminal is identified in the SCI, and the first terminal determines the TBS for sending the information by using the MCS Table.

In specific implementation, a 2bits information field is introduced into the SCI to identify the MCS table used by the first terminal.

Specifically, a 2-bits information field may be introduced into the SCI to indicate the MCS Table used by the terminal, and the sending terminal itself selects and uses an appropriate MCS Table to calculate the TBS according to the actual situation. And the receiving terminal judges which MCS Table should be used for calculating the TBS according to the corresponding information bit in the received SCI.

The following is an example.

Example 4:

the embodiment mainly aims at the scheme two, and the terminal is in a CSI-only state:

a sending end:

1) at this time, the first terminal is in the CSI-only state, so a low-spectral efficiency64QAM MCS table is used and indicated in the information field corresponding to the SCI. And calculating the corresponding TBS for sending resources according to the TBS determination.

Receiving end:

1) the second terminal receives the information from the first terminal, can obtain the MCS Table used in the receiving process through the SCI, and calculates the corresponding TBS to receive the resource.

The third scheme is as follows:

in the scheme, when the first terminal only carries the CSI without data, padding bits are filled in the MAC layer according to an agreed padding mechanism to ensure that the total bit number is equal to the TBS for transmitting information determined according to the MCS table.

In a specific implementation, padding bits are filled by circularly mapping MAC CE information at the MAC layer until the number of spare bits is filled.

Specifically, the scheme does not need to introduce additional information bits into SCI, but rather appoints a padding bit mechanism in the MAC layer processing process.

A sending end:

1) when the first terminal sends data, the physical layer TBS is first calculated according to the configured MCS table and the MCS level in the SCI. The MAC layer ensures that the total number of bits can be equal to the TBS by adjusting the padding bits of the last part.

2) In the MAC layer final padding field padding process, the total number of bits can be matched to the TBS by padding "0" or by cyclically mapping MAC CE information.

Receiving end:

1) after the second terminal receives the data sent by the first terminal, the TBS is calculated according to the MCS Table configured by the resource pool and the MCS level indicated in the SCI, so that the data is received

2) Then, according to a padding mechanism agreed in advance, the MAC data packet is decoded;

the following is an example.

Example 5:

the embodiment is mainly directed to scheme three, and the first terminal is in a CSI-only state:

a sending end:

1) the first terminal only sends CSI information, and at the moment, the data channel only comprises SL-SCH subheader + R/LCID subheader + MAC CE + padding bits. After the TBS is calculated by using the MCS Table configured in the resource pool and the MCS level in the SCI, the MAC layer supplements bits through padding bits to achieve the matched TBS;

2) wherein padding bits can be all '0' or cyclic repetition mapping of CSI information;

receiving end:

1) and after receiving the information sent by the first terminal, the second terminal calculates the TBS by using the MCS Table configured by the resource pool and the MCS level indication in the received SCI.

2) Performing demapping according to a padding mechanism agreed in advance;

3) if the padding mechanism is to cyclically and repeatedly map information in the MAC CE, the information can be understood as repeated transmission, so that the reliability is improved;

based on the same inventive concept, the embodiment of the present invention further provides a terminal, a CSI feedback device, a CSI receiving device, and a computer readable storage medium, and because the principles of these devices for solving the problems are similar to the CSI feedback method and the CSI receiving method, the implementation of these devices may refer to the implementation of the methods, and repeated parts are not described again.

When the technical scheme provided by the embodiment of the invention is implemented, the implementation can be carried out as follows.

Fig. 4 is a schematic structural diagram of a first terminal, as shown in the figure, the terminal includes: a processor 400, a memory 420, and a transceiver 410, wherein:

the processor 400, which is used to read the program in the memory 420, executes the following processes:

when feeding back CSI, sending the CSI according to a rule agreed with a second terminal receiving the CSI, wherein the agreed rule comprises one or the combination of the following modes:

when the first terminal only bears CSI and has no data, padding bits according to an agreed padding mechanism at an MAC layer to ensure that the total bit number is equal to the TBS of the sending information determined according to the MCS table;

a transceiver 410 for receiving and transmitting data under the control of the processor 400.

Where in fig. 4, the bus architecture may include any number of interconnected buses and bridges, with various circuits of one or more processors, represented by processor 400, and memory, represented by memory 420, being linked together. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further herein. The bus interface provides an interface. The transceiver 410 may be a number of elements including a transmitter and a receiver that provide a means for communicating with various other apparatus over a transmission medium. For different user devices, the user interface 430 may also be an interface capable of interfacing with a desired device externally, including but not limited to a keypad, display, speaker, microphone, joystick, etc.

The processor 400 is responsible for managing the bus architecture and general processing, and the memory 420 may store data used by the processor 400 in performing operations.

The embodiment of the invention also provides a CSI feedback device of the direct link, which comprises the following concrete steps:

fig. 5 is a schematic structural diagram of a CSI feedback apparatus for a direct link, as shown in the figure, including:

a first determining module 501, configured to determine CSI to be fed back;

a sending module 502, configured to send CSI according to a rule agreed with a second terminal receiving CSI when feeding back CSI, where the agreed rule includes one or a combination of the following manners:

selecting an MCS Table, identifying the used MCS Table in the SCI, and determining the TBS of the transmitted information by using the MCS Table; or the like, or, alternatively,

when the first terminal only carries CSI but has no data, padding bits according to an agreed padding mechanism at an MAC layer to ensure that the total bit number is equal to the TBS of the transmission information determined according to the MCS table.

For convenience of description, each part of the above-described apparatus is separately described as being functionally divided into various modules or units. Of course, the functionality of the various modules or units may be implemented in the same one or more pieces of software or hardware in practicing the invention.

Fig. 6 is a schematic structural diagram of a second terminal, as shown in the figure, the terminal includes: a processor 600, a memory 620, and a transceiver 610, wherein:

the processor 600, which is used to read the program in the memory 620, executes the following processes:

a transceiver 610 for receiving and transmitting data under the control of the processor 600.

Where in fig. 6, the bus architecture may include any number of interconnected buses and bridges, with various circuits being linked together, particularly one or more processors represented by processor 600 and memory represented by memory 620. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further herein. The bus interface provides an interface. The transceiver 610 may be a number of elements including a transmitter and a receiver that provide a means for communicating with various other apparatus over a transmission medium. For different user devices, the user interface 630 may also be an interface capable of interfacing with a desired device externally, including but not limited to a keypad, display, speaker, microphone, joystick, etc.

The processor 600 is responsible for managing the bus architecture and general processing, and the memory 620 may store data used by the processor 600 in performing operations.

The embodiment of the invention also provides a CSI receiving device of the direct link, which comprises the following concrete steps:

fig. 7 is a schematic structural diagram of a CSI receiving apparatus for a direct link, as shown, including:

a receiving module 701, configured to receive, by a second terminal, CSI fed back by a first terminal according to an agreed rule when the second terminal receives CSI sent by the first terminal, where the agreed rule includes one or a combination of the following manners:

determining whether the first terminal only carries CSI without data according to the identification in the SCI, and when the identification indicates that the first terminal only carries the CSI without data, taking a preset TBS as a TBS for sending information; or the like, or, alternatively,

and after the TBS of the received information is determined according to the MCS table, decoding padding bits according to an agreed padding mechanism at the MAC layer.

In the detailed implementation, reference may be made to the implementation of the CSI feedback method and/or the CSI receiving method.

In summary, in the technical solution provided in the embodiment of the present invention, a 1bit information field is introduced into the SCI for indicating the sending of the CSI-only state, and if the UE is in the CSI-only state, the terminal is forced to use a low-spectral efficiency64QAM MCS table; or, if the UE is in the CSI-only state, the preconfigured TBS is directly used.

Or, a 2bits information field can be introduced into the SCI to indicate the MCS Table used by the terminal, and the transmitting terminal selects and uses an appropriate MCS Table to calculate the TBS according to the actual situation.

It may also be unnecessary to introduce additional information bits in the SCI. The mechanism for padding bits is agreed during MAC layer processing.

By the scheme, a TBS solution is provided for the CSI-only state, the spectrum efficiency can be improved and the CSI receiving reliability can be improved for the CSI-only state, and the terminal can autonomously select a proper MCS table.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A method for feeding back Channel State Information (CSI) of a sidelink through, comprising:

2. The method of claim 1, wherein whether the first terminal carries only CSI without data is identified by introducing a 1bit information field in the SCI.

3. The method of claim 1 wherein the MCS table used by the first terminal is identified by introducing a 2bits information field in the SCI.

4. The method of claim 1, wherein padding bits are filled by cyclically mapping MAC CE information at a MAC layer until the number of spare bits is filled.

5. A CSI receiving method for a direct link, comprising:

6. The method of claim 5, wherein whether the first terminal carries only CSI without data is identified by introducing a 1-bit information field in the SCI.

7. The method of claim 5, wherein the used MCS Table is identified by introducing a 2-bits information field in the SCI.

8. The method of claim 5, wherein padding bits are filled by cyclically mapping MAC CE information at a MAC layer until the number of spare bits is filled.

9. A first terminal, comprising: a processor, a memory, and a transceiver, comprising:

10. The terminal of claim 9, wherein whether the first terminal carries only CSI without data is identified by introducing a 1-bit information field in the SCI.

11. The terminal of claim 9, wherein the MCS table used by the first terminal is identified by introducing a 2bits information field in the SCI.

12. The terminal of claim 9, wherein padding bits are padded by cyclically mapping MAC CE information at a MAC layer until the number of spare bits is filled.

13. A second terminal, comprising: a processor, a memory, and a transceiver, comprising:

when receiving the CSI sent by the first terminal, receiving the CSI fed back by the first terminal according to an agreed rule; wherein the agreed rule comprises one or a combination of the following modes:

14. The terminal of claim 13, wherein whether the first terminal carries only CSI without data is identified by introducing a 1-bit information field in the SCI.

15. The terminal of claim 13, wherein the MCS Table used is identified by introducing a 2bits information field in the SCI.

16. The terminal of claim 13, wherein padding bits are padded by cyclically mapping MAC CE information at a MAC layer until the number of spare bits is filled.

17. A CSI feedback apparatus for a direct link, comprising:

18. A CSI receiving apparatus of a direct link, comprising:

19. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program for executing the method of any one of claims 1 to 8.