CN108632782B

CN108632782B - Transmitting and receiving method and device in V2X communication

Info

Publication number: CN108632782B
Application number: CN201810053841.7A
Authority: CN
Inventors: 王轶; 李迎阳; 张世昌
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2017-03-24
Filing date: 2018-01-19
Publication date: 2023-11-21
Anticipated expiration: 2038-01-19
Also published as: CN108632782A

Abstract

The embodiment of the application provides a transmitting and receiving method in vehicle-to-outside V2X communication, which comprises the following steps: the first class of UEs detects PSCCHs in SCI X transmitted by other UEs, determines from SCI X whether to further measure the PSSCH-RSRP of the SCI X scheduled PSSCH, and further demodulates the SCI X scheduled PSSCH. The method provided by the application further comprises the following steps: the second class of UEs detects PSCCHs in SCI X transmitted by other UEs and determines the TBS of the PSSCH scheduled by SCI X based on the modulation and coding bit field in SCI X and predefined TBS mapping criteria. The method provided by the application further comprises the following steps: and the second class of UE determines the PSCCH of SCI X and the transmission power of the PSSCH scheduled by the SCI X according to the modulation mode. By the method, the coexistence problem of the first V2X UE and the second V2X UE can be better realized, and the transmission efficiency of the second V2X UE is improved.

Description

Transmitting and receiving method and device in V2X communication

Technical Field

The application relates to the technical field of communication, in particular to a method for transmitting and receiving bypass control information SCI (Sidelink control information) borne on a PSCCH in vehicle-to-outside (V2X) communication, and a method for measuring and demodulating the PSSCH based on SCI scheduling.

Background

In the 3GPP standard, the direct communication link between devices to settings is called bypass (sidlink), and like uplink and downlink, there are also control channels and data channels on the bypass, the former called bypass control channel (english: physical Sidelink Control CHannel, acronym: PSCCH), and the latter called bypass data channel (english: physical Sidelink Shared CHannel, acronym: PSSCH). The PSCCH is used to indicate a time-frequency domain resource location of PSSCH transmission, a modulation coding scheme, a priority of data carried in the PSSCH, and the like, and the PSSCH is used to carry data.

Control information and data in vehicle-to-outside communication (english: vehicle to Vehicle/petestrian/Infrastructure/Network, acronym: V2X) can be transmitted through a bypass, where V2X communication includes two transmission modes, namely transmission Mode 3 (Mode 3) and transmission Mode 4 (Mode 4). In Mode 4, the transmission resources of the PSCCH and the PSSCH are autonomously selected by the UE according to the channel detection result. In the channel detection process, the UE firstly determines the time-frequency resource position and the priority of a scheduled PSSCH by receiving PSCCH sent by other UE, then further detects the demodulation reference channel receiving power (PSSCH-RSRP) of the scheduled PSSCH, and excludes resources with PSSCH-RSRP higher than a specific threshold; the UE then calculates the average received energy (S-RSSI) of the remaining resources and finally randomly selects one resource from the partial resources with the lowest S-RSSI as the transmission resource.

In V2X communication of LTE Rel-14, transmission of PSSCH is specified in consideration of implementation complexity, and only QPSK and 16QAM modulation are employed, and 64QAM modulation is not employed. Whereas for LTE Rel-15 or later versions of V2X devices, 64QAM modulation will be supported for increased transmission rates as device capabilities are enhanced. In order to support coexistence of V2X devices of LTE Rel-14 (referred to as first class V2X UEs) with V2X devices of LTE Rel-15 or later releases (referred to as second class V2X UEs), it is required that the first class V2X UEs be able to demodulate SCI (bypass control information: sidelink control information) of the second class V2X UEs and select their own transmission resources according to the SCI. Therefore, it is necessary to define the behavior of the first class V2X UEs when receiving SCI indicating 64 QAM. SCI has different formats, and SCI in various formats will be collectively referred to as SCI X hereinafter.

In general, when a packet is initially transmitted, if the coding rate exceeds 0.93, the ue may not properly demodulate the packet. Thus, the UE may not demodulate the data packet. In LTE Rel-14V2X communication, since the first symbol is used as Automatic Gain Control (AGC) adjustment, the 3,6,9, 12 th symbol maps demodulation reference signal (DM-RS), and the last symbol is used as Gap (Gap) in 14 symbols of one subframe, the symbols actually available for effective data transmission are 8 symbols. In Rel-15 or later, if 8 symbols are still available after 64QAM is introduced, there may be multiple MCSindex coding rates exceeding 0.93 in the existing MCS table, so that the UE cannot demodulate correctly. Therefore, an existing MCS table needs to be adjusted.

In the conventional LTE Rel-14V2X communication, the PSCCH having the format SCI X is transmitted only once, and 2 times of PSSCH transmission are scheduled. To ensure the same reception performance, the power of the PSCCH formatted SCI X is 2 times the power of the PSCCH scheduled by SCI X. In LTE Rel-15 or later, however, as the PSSCH modulation coding rate increases, the existing power relationship is not optimal and needs to be improved in order to achieve the same reception performance of the PSSCH and PSCCH.

Disclosure of Invention

The application provides a sending and receiving method and equipment in V2X communication, which are used for better realizing the coexistence problem of a first V2X UE and a second V2X UE.

The application discloses a receiving method in vehicle-to-outside V2X communication, which comprises the following steps:

A. the User Equipment (UE) receives bypass control channels (PSCCH) sent by other UE and detects bypass control information (SCI) sent by the PSCCH;

B. the UE determines parameter information of a bypass data channel PSSCH scheduled by the SCI according to the SCI;

C. the UE determines whether to receive and measure the demodulation reference channel receiving power PSSCH-RSRP of PSSCH scheduled by SCI and/or the average receiving energy S-RSSI of the residual resources according to the parameter information of the PSSCH, and selects the sending resources according to the measurement information;

D. The UE receives the PSSCH scheduled by the SCI according to the SCI, and determines whether to demodulate the PSSCH according to the SCI.

Preferably, the B includes: V2X UE of the first class is based on the value I of MSC bit domain of SCI modulation coding mode _MCS Determining a modulation mode of PSSCH of other UE, and correspondingly, implementing the C and the D by the V2X UE of the first type according to at least one of the following modes:

mode one: if I _MCS >20, the first V2X UE measures PSSCH-RSRP and/or S-RSSI of the scheduled PSSCH according to the parameter information of the PSCCH, selects transmission resources according to the measurement information, and demodulates or skips demodulating the PSSCH scheduled by the PSCCH;

mode two: if I _MCS >20, when modulation scheme Q ' =min (4, Q ' ' _m ) When the calculated effective channel coding rate is greater than the set threshold Thc, the V2X UE of the first class measures PSSCH-RSRP and/or S-RSSI of the scheduled PSSCH according to the parameter information of the PSCCH, selects transmission resources according to the measurement information, and demodulates or skips demodulating the PSSCH scheduled by the PSCCH; when modulation scheme Q ' =min (4, Q ' ' _m ) When the calculated effective channel coding rate is less than or equal to a set threshold Thc, the V2X UE of the first class measures PSSCH-RSRP and/or S-RSSI of the scheduled PSSCH according to parameter information of the PSCCH, selects transmission resources according to the measurement information, and demodulates the PSSCH scheduled by the PSCCH;

Mode three: when 20 is<I _MCS <29, when modulation scheme Q ' =min (4, Q ' ' _m ) When the calculated effective channel coding rate is greater than the set threshold Thc, the V2X UE of the first class measures PSSCH-RSRP and/or S-RSSI of the scheduled PSSCH according to the parameter information of the PSCCH, selects transmission resources according to the measurement information, and demodulates or skips demodulating the PSSCH scheduled by the PSCCH; when modulation scheme Q ' =min (4, Q ' ' _m ) When the calculated effective channel coding rate is less than or equal to a set threshold Thc, the V2X UE of the first class measures PSSCH-RSRP and/or S-RSSI of the scheduled PSSCH according to parameter information of the PSCCH, selects transmission resources according to the measurement information, and demodulates the PSSCH scheduled by the PSCCH; when I _MCS When the PSSCH is not less than 29, the first V2X UE demodulates or skips demodulation of the PSSCH, and skips measurement of PSSCH-RSRP; i _MCS Nor is the MCS used by the second class V2X UEs to indicate the PSSCH;

mode four: if I _MCS >20, when modulation scheme Q ' =min (4, Q ' ' _m ) When=4, the first V2X UE judges the number of PSSCHs scheduled by the PSCCH and calculates an effective channel coding rate, if the effective channel coding rate is greater than a set threshold Thc, the first V2X UE measures PSSCH-RSRP and/or S-RSSI of the scheduled PSSCH according to parameter information of the PSCCH, selects transmission resources according to the measurement information, and demodulates or skips demodulating the PSSCH scheduled by the PSCCH; when modulation scheme Q ' =min (4, Q ' ' _m ) When the calculated effective channel coding rate is less than or equal to a set threshold Thc, the V2X UE of the first class measures PSSCH-RSRP and/or S-RSSI of the scheduled PSSCH according to parameter information of the PSCCH, selects transmission resources according to the measurement information, and demodulates the PSSCH scheduled by the PSCCH;

wherein Q' _m According to I _MCS And (5) determining a modulation mode.

Preferably, the B includes: the first V2X UE determines the resource reservation information of PSSCH of other UE according to the resource reservation bit field of SCI, and correspondingly, the first V2X UE realizes the C and D in the following modes:

mode five: if the value indicated by the resource reservation bit field in PSCCH of other UE is more than or equal to Thr_int, the V2X UE of the first type measures PSSCH-RSRP and/or S-RSSI of the scheduled PSSCH according to the parameter information of the PSCCH, selects transmission resources according to the measurement information, and demodulates or skips demodulating the PSSCH scheduled by the PSCCH; wherein, the first V2X UE performs PSSCH-RSRP measurement based on PSSCH scheduled by the PSCCH, and does not use the measurement result in subframes of other PSSCH transmitted later.

Preferably, if the first V2X UE determines that the transport block size TBS exceeds the maximum UE capability according to the MCS information of the received PSCCH, the first V2X UE measures the PSSCH-RSRP and/or S-RSSI of the scheduled pscsch according to the information of the PSCCH, selects transmission resources according to the measurement information, and demodulates or skips demodulating the PSCCH scheduled pscsch.

Preferably, the B includes: the second V2X UE determines the effective channel coding rate of PSSCH scheduled by PSCCH of other UE according to SCI;

the second class V2X UE implements the selecting of the transmission resources according to the measurement information in the C according to at least one or more of the following ways: mode one: the UE performing transmission resource selection determines the threshold of PSSCH-RSRP from other UEs according to the modulation scheme to be adopted. And if the PSSCH-RSRP from other UE is higher than the threshold, eliminating the resources corresponding to the PSSCH when the transmission resource selection is carried out.

Further, the PSSCH-RSRP threshold corresponding to the 64QAM modulation scheme is lower than the PSSCH-RSRP threshold corresponding to the QPSK or 16QAM modulation scheme.

Mode two: after the UE for selecting the transmission resources excludes the resources higher than the PSSCH-RSRP threshold, the proportion of the residual resources to the total resources in the resource selection window must not be lower than a specific threshold Thr_step2_ratio; and the UE for selecting the transmission resources calculates the average received energy (S-RSSI) of the residual resources, sequentially picks up the residual resources according to the order of the S-RSSI from small to large until the proportion of all the picked resources to the total resources in a resource selection window is not lower than a specific threshold Thr_step3_ratio, and randomly selects one resource from the picked resources as the transmission resource. The specific threshold thr_step2_ratio and/or thr_step3_ratio may be determined according to a modulation scheme to be adopted by the UE performing the transmission resource selection.

Further, the specific threshold corresponding to the 64QAM modulation scheme is lower than the specific threshold corresponding to the QPSK or 16QAM modulation scheme.

Mode three: the UE performing transmission resource selection also determines the threshold of the PSSCH-RSRP from other UEs according to the modulation scheme of the PSCCH instruction received from other UEs.

Further, when the modulation scheme indicated by the PSCCH from other UEs is 64QAM, the PSSCH-RSRP threshold is lower than the PSSCH-RSRP threshold when the modulation scheme indicated by the PSCCH is QPSK or 16 QAM.

The second class V2X UEs implement said C and D in at least one of the following ways:

mode six: if the effective channel coding rate of PSSCH scheduled by PSCCH of other UE is greater than the set threshold Thc, the second V2X UE measures PSSCH-RSRP and/or S-RSSI of the scheduled PSSCH according to the information of the PSCCH, selects transmission resources according to the measurement information, and demodulates or skips demodulating the PSSCH scheduled by the PSCCH;

mode seven: if the effective channel coding rate of PSSCH scheduled by PSCCH of other UE is greater than the set threshold Thc, the second V2X UE does not measure PSSCH-RSRP and/or S-RSSI of the scheduled PSSCH according to the information of PSCCH, and demodulates or skips demodulating PSSCH scheduled by PSCCH.

Preferably, the B includes: and the second V2X UE determines TBS according to the modulation coding mode indication information of SCI and the frequency domain resource position information.

Preferably, the TBS is determined in at least one of the following ways:

mode one of determining TBS: according to the jointThe received frequency domain resource position information indicated in the PSCCH determines that the number of PRBs occupied by PSSCH scheduled by the PSCCH is N' _PRB And according to N _PRB A look-up table determines the TBS, wherein,

preferably, the beta used may be different for PSSCHs having different transmission time lengths.

Mode two of determining TBS: when I _MCS >When Th_mcs1 is used, according to the frequency domain resource position information indicated in the received PSCCH, the PRB number occupied by PSSCH scheduled by PSCCH is determined to be N' _PRB And according to N _PRB A look-up table determines the TBS, wherein,when I _MCS When the number of PRBs occupied by PSSCH scheduled by PSCCH is less than or equal to Th_mcs1, determining that the number of PRBs occupied by PSSCH scheduled by PSCCH is N according to the received frequency domain resource position information indicated in the PSCCH _P ′ _RB And according to N' _PRB Table lookup to determine TBS; th_mcs1 is a preset value;

Preferably, for PSSCHs having different transmission time lengths, the corresponding th_mcs1 may be different.

Mode three of determining TBS: for UEs that can distinguish whether the received PSCCH is from a first type V2X UE or a second type V2X UE:

if the received PSCCH comes from the V2X UE of the first class, determining that the number of PRBs occupied by PSSCH scheduled by the PSCCH is N according to the frequency domain resource position information indicated in the received PSCCH _P ′ _RB And according to N _P ′ _RB Table lookup to determine TBS;

if the received PSCCH comes from the second V2X UE, determining that the number of PRBs occupied by PSSCH scheduled by the PSCCH is N according to the frequency domain resource position information indicated in the received PSCCH _P ′ _RB And according to N _PRB A look-up table determines the TBS, wherein,alternatively, if the received PSCCH is from a second class V2X UE, when I _MCS >When Th_mcs1 is used, according to the received frequency domain resource position information indicated in PSCCH, determining that the number of PRBs occupied by PSSCH scheduled by PSCCH is N _P ′ _RB And according to N _PRB Determining TBS by looking up a table, wherein->When I _MCS When the number of PRBs occupied by PSSCH scheduled by PSCCH is less than or equal to Th_mcs1, determining that the number of PRBs occupied by PSSCH scheduled by PSCCH is N according to the received frequency domain resource position information indicated in the PSCCH _P ′ _RB And according to N _P ′ _RB The TBS is determined by looking up a table.

Preferably, for any of the ways of determining TBS, β=0.75, or β=0.8, or β=2/3, or β is a non-negative number of no more than 1 configured.

Preferably, for the second or third mode of determining TBS:

th_mcs1 is the minimum I corresponding to 64QAM _MCS ；

Alternatively, th_msc1=18;

or, for the PRB number possibly occupied by PSSCH, respectively determining corresponding Th_msc1 to enable all the corresponding I of 64QAM _MCS And I in 16QAM which may result in an effective code rate greater than 0.93 _MCS At N _P ′ _RB After weighting, the effective coding rate of the corresponding TBS is smaller than or equal to 0.93;

alternatively, th_msc1=23.

The application also provides a user equipment, comprising: the system comprises a control information detection module, a parameter determination module, a transmission resource selection module and a demodulation module, wherein:

the control information detection module is used for receiving PSCCH sent by other UE and detecting SCI sent by the PSCCH;

the parameter determining module is used for determining parameter information of PSSCH scheduled by the SCI according to the SCI by the UE;

the sending resource selection module is used for determining whether to receive and measure PSSCH-RSRP and/or S-RSSI of PSSCH scheduled by SCI according to parameter information of PSSCH, and selecting sending resources according to measurement information;

the demodulation module is used for receiving the PSSCH scheduled by the SCI according to the SCI, and determining whether to demodulate the PSSCH according to the SCI.

The application also provides a method for determining the channel transmitting power, which comprises the following steps:

for the SCI carried on the PSCCH and its scheduled PSCCH, the power spectral density, PSD, offset of the PSCCH from the PSCCH is determined in any of the following ways:

mode one: PSD offset of PSCCH relative to PSSCH is irrelevant to PSSCH and PSCCH modulation modes, and total power of PSSCH and PSCCH increases along with the increase of PSSCH and/or PSCCH modulation modes;

mode two: the PSD offset of PSCCH relative to PSSCH is related to PSSCH and PSCCH modulation modes, and the total power of PSSCH and PSCCH increases with the increase of PSSCH and/or PSCCH modulation modes;

mode three: PSD of PSSCH is determined according to modulation mode of PSSCH.

The application also provides a user equipment, comprising: a transmit power determination module and a transmit module, wherein:

for SCI carried on PSCCH and its scheduled PSSCH, the transmit power determination module is configured to determine a power spectral density, PSD, offset of the PSSCH from the PSCCH in any of the following ways:

mode three: PSD of PSSCH is determined according to modulation mode of PSSCH;

the transmitting module is used for transmitting according to the power determined by the transmitting power determining module.

As can be seen from the above technical solution, the transmission and receiving method in V2X communication provided by the present application enables a V2X UE of a lower version and a V2X UE of a higher version to determine, according to scheduling information of the other party, an interference level of resources that the other party can occupy, so that the user can avoid resources with strong interference when selecting transmission resources. In addition, the application also enables the V2X UE to determine the proper size of the transmission block according to the actually occupied resources, thereby improving the transmission efficiency.

Drawings

Fig. 1 is a flowchart of a PSCCH receiving method in V2X communication according to a first embodiment of the present application;

fig. 2 is a flowchart of a PSCCH receiving method in V2X communication according to a second embodiment of the present application;

FIG. 3 is a schematic diagram of a preferred UE structure according to the present application;

Fig. 4 is a schematic diagram of the composition structure of another preferred ue according to the present application.

Detailed Description

Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the application.

As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless expressly stated otherwise, as understood by those skilled in the art. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or wirelessly coupled. The term "and/or" as used herein includes all or any element and all combination of one or more of the associated listed items.

It will be understood by those skilled in the art that all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs unless defined otherwise. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

As used herein, a "terminal" or "terminal device" includes both a device of a wireless signal receiver having no transmitting capability and a device of receiving and transmitting hardware having receiving and transmitting hardware capable of bi-directional communication over a bi-directional communication link, as will be appreciated by those skilled in the art. Such a device may include: a cellular or other communication device having a single-line display or a multi-line display or a cellular or other communication device without a multi-line display; a PCS (Personal Communications Service, personal communication system) that may combine voice, data processing, facsimile and/or data communication capabilities; a PDA (Personal Digital Assistant ) that can include a radio frequency receiver, pager, internet/intranet access, web browser, notepad, calendar and/or GPS (Global Positioning System ) receiver; a conventional laptop and/or palmtop computer or other appliance that has and/or includes a radio frequency receiver. As used herein, "terminal," "terminal device" may be portable, transportable, installed in a vehicle (aeronautical, maritime, and/or land-based), or adapted and/or configured to operate locally and/or in a distributed fashion, to operate at any other location(s) on earth and/or in space. The "terminal" and "terminal device" used herein may also be a communication terminal, a network access terminal, and a music/video playing terminal, for example, may be a PDA, a MID (Mobile Internet Device ), and/or a mobile phone with a music/video playing function, and may also be a smart tv, a set top box, and other devices.

Embodiment one:

in order to improve the transmission rate of the second class V2X UE, a higher modulation scheme, 64QAM, is introduced. In order to support coexistence of the first type V2X UE and the second type V2X UE, the first type V2X UE needs to consider resources that the second type V2X UE may occupy when selecting transmission resources. One resource includes one or more contiguous sub-channels, and one sub-channel includes N contiguous Physical Resource Blocks (PRBs), where N is configured or preconfigured for higher layer signaling. The existing transmission resource selection method includes the following steps (see section 14.1.1.6 in TS 36.213):

step1: the V2X UE of the first class determines the time-frequency resource location and priority of the scheduled PSCCH by receiving PSCCH transmitted by other UEs.

The other UEs may be UEs of the same type or UEs of different types.

Step2: the first class of V2X UEs detects the demodulation reference channel received power of the scheduled PSSCH (referred to as PSSCH-RSRP measurement) and excludes resources for which the PSSCH-RSRP is above a certain threshold. For example, if the proportion of the remaining resources is less than 20% of the total resources in the resource selection window, the specific threshold is increased by 3dB, and the step is re-executed until the proportion of the remaining resources is not less than 20%.

Step3: the first V2X UE calculates the average received energy (S-RSSI) of the residual resources, and randomly selects one resource from the partial resources with the lowest S-RSSI as a transmitting resource. For example, the remaining resources are sequentially sorted out from the remaining resources in the order of from small to large S-RSSI until the proportion of all the sorted out resources is not lower than 20% of the total resources in the resource selection window. And randomly selecting one resource from the selected resources as a transmission resource.

It is apparent from the above method that it is necessary to enable the V2X UE of the first type to correctly demodulate the PSCCH of the V2X UE of the second type, so that the resources of the PSCCH indicated by the PSCCH can be measured in Step2 and/or Step3, and an appropriate resource is selected as the transmission resource. However, the V2X UE of the first class only supports QPSK and 16QAM modulation, that is, when the V2X UE of the first class receives PSCCH (PSCCH of LTE Rel-14 contains bit information as shown in table 1) from the V2X UE of the second class, and reads the MSC bit field therein, and finds that the modulation mode indicated by the MSC bit field is 64QAM, for example, I in table 2 _MCS >At 20, the prior art does not define the behavior of the UE.

TABLE 1

(see 3GPP TS 36.212 5.4.3.1.2)

TABLE 2

(see 3GPP TS 36213 8.6.1-1:Modulation,TBS index and redundancy version table for PUSCH)

The embodiment proposes that, under the above situation, the first V2X UE may be resolved according to the following several implementation manners:

mode one: when the first V2X UE performs transmission resource selection, if I in PSCCH from other UEs is solved _MCS >20, the V2X UEs of the first class perform steps 1 to step3 according to the information of the PSCCH, but the V2X UEs of the first class may not attempt to demodulate the PSCCH scheduled PSCCH. The "no attempt to demodulate" described in the present application corresponds to "may skip decoding", namely: the first V2X UEs may demodulate the PSCCH scheduled pschs, and may skip demodulating PSCCH scheduled pschs, as follows.

Mode two: when the first V2X UE performs transmission resource selection, if I in PSCCH from other UEs is solved _MCS >20, and when modulation scheme Q '=min (4, Q' _m ) When=4 (wherein Q' _m For the purposes of Table 2 according to I _MCS Determined modulation mode), the calculated effective channel coding rate is greater than a predefined threshold Thc, for example thc=0.93, and the first type V2X UE performs steps 1 to step3 according to the information of the PSCCH, but the first type V2X UE may not attempt to demodulate the PSCCH scheduled PSCCH. And when the modulation scheme Q ' =min (4, Q ' ' _m ) When the calculated effective channel coding rate is equal to or less than the predefined threshold Thc, step 1-step 3 is performed by the V2X UE of the first class according to the information of the PSCCH, and the V2X UE of the first class tries to demodulate the PSCCH scheduled PSCCH.

Wherein only a single transmission is considered when calculating the effective channel coding rate. Specifically, when calculating the effective channel coding rate, the effective channel coding rate is calculated according to I in Table 2 _MCS Determining TBS index I _TBS And determines a TBS according to table 7.1.7.2.1-1 or 7.1.7.2.2-1 in 3gpp TS 36.213 and adds a Cyclic Redundancy Check (CRC) as a numerator for calculating an effective channel coding rate, and then takes the physical channel bit number of the PSSCH as a denominator for calculating the effective channel coding rate, for example, the physical channel bit number of the PSSCH is: number of allocated Resource Blocks (RBs) number of available symbols (8 symbols) per RB number of subcarriers modulation order Q'.

Another implementation of the second mode is: mode three: when 20 is<I _MCS <29 according to the method described in the second mode above. When I _MCS And when the PSSCH is not demodulated, the first V2X UE can neither demodulate the PSSCH nor measure the PSSCH-RSRP. In this case, I _MCS Nor are the MCSs used by the second class V2X UEs to indicate the PSSCH.

Mode four: when the first V2X UE performs transmission resource selection, if I in PSCCH from other UEs is solved _MCS >20, and when modulation scheme Q '=min (4, Q' _m ) When=4 (wherein Q' _m For the purposes of Table 2 according to I _MCS The determined modulation scheme), the V2X UE of the first class further determines the number of PSCCHs scheduled by the PSCCH that are expected to be received, i.e., whether to transmit once or twice (e.g., if a PSCCH primary transmission is received, and by "primary and secondary" in table 2 The time interval of transmission "indicates that it is determined that there is one PSCCH retransmission, then there are two transmissions. ) An effective channel coding rate is calculated. For example, if there are two transmissions, the effective channel coding rate is calculated based on the two transmissions combined. If the effective channel coding rate is greater than a predefined threshold Thc, for example thc=0.93, the V2X UEs of the first class perform steps 1 to 3 according to the information of the PSCCH, but the V2X UEs of the first class may not attempt to demodulate the PSCCH scheduled pscsch. And when the modulation scheme Q ' =min (4, Q ' ' _m ) When the calculated effective channel coding rate is equal to or less than the predefined threshold Thc, step 1-step 3 is performed by the V2X UE of the first class according to the information of the PSCCH, and the V2X UE of the first class tries to demodulate the PSCCH scheduled PSCCH.

Note that for the above three implementations, if the first class V2X UE determines from the received MCS information of the PSCCH that the Transport Block Size (TBS) exceeds the maximum UE capability, e.g., 31704, then the first class V2X UE performs steps 1-step 3 from the information of the PSCCH, but does not attempt to demodulate the PSCCH scheduled PSCCH.

Mode five: when the first V2X UE performs transmission resource selection, if the value indicated by the 'resource reservation' bit field in PSCCH of other UEs is not less than Thr_int, the first V2X UE performs step 1-step 3 according to the information of the PSCCH, but does not attempt to demodulate PSSCH scheduled by the PSCCH. In step2 and/or step3, the V2X UE of the first class performs PSSCH-RSRP measurement based on the PSSCH scheduled by the PSCCH, but does not use the measurement result in subframes of other PSSCH that may be transmitted subsequently.

In existing V2X communications, the UE may reserve resources of multiple subframes for the PSSCH that may be subsequently transmitted through the "resource reservation" bit field indication. That is, the UE indicates one or two PSCCH transmissions scheduled by the PSCCH over the current PSCCH and may inform other UEs over the PSCCH in which subframes the transmitting UE may transmit other PSCCHs. In existing step2 and/or step3, the UE measures the PSSCH-RSRP and S-RSSI of the PSSCH indicated by the PSCCH and assumes that the same RSRP/RSSI is also present in these reserved subframes. However, in the fourth mode, when the value indicated by the "resource reservation" bit field is greater than or equal to thr_int, the first type V2X UE cannot determine the reserved subframe position. However, the V2X UEs of the first class may still measure PSSCH-RSRP and S-RSSI of the PSSCH indicated by the PSCCH, and consider interference that may be caused by the PSSCH when selecting resources.

Preferably thr_int=13.

A flowchart of a PSCCH receiving method in V2X communication according to this embodiment is shown in fig. 1, and includes the following steps 101 to 103:

step 101: the UE detects PSCCH in SCI X format sent by other UEs.

Step 102: the UE determines the modulation order of PSSCH scheduled by SCI X according to the modulation coding indication information (i.e., MSC bit field) of SCI X, and determines whether to measure PSSCH-RSRP and/or S-RSSI of PSSCH scheduled by SCI X according to SCI X, and selects transmission resources according to the measurement information.

Wherein the first V2X UE is performed according to one of the modes one to five.

The second class V2X UE then determines whether to measure PSSCH-RSRP and/or S-RSSI of the SCI X scheduled PSSCH according to one of the following manners six-seven:

mode six: when the second type V2X UE performs transmission resource selection, if the effective channel coding rate of the PSCCH scheduled by the other UE is greater than a predefined threshold Thc, for example, thc=0.93 (which may be defined as an effective channel coding rate of one transmission or an effective channel coding rate determined according to the number of times of transmission of the received PSCCH), the second type V2X UE performs steps 1 to 3 according to the PSCCH information, but the second type V2X UE does not attempt to demodulate the PSCCH scheduled by the PSCCH.

Mode seven: when the second class V2X UE performs transmission resource selection, if the effective channel coding rate of the PSCCH scheduled PSCCH decoded by other UEs is greater than a predefined threshold Thc, for example thc=0.93, the second class V2X UE may perform steps 1 to 3 according to the information of the PSCCH, or may not attempt to demodulate the PSCCH scheduled PSCCH.

When the second type V2X UE determines that PSSCH-RSRP and/or S-RSSI measurement is required for the PSSCH according to the PSCCH of the other UE that is detected according to the manner six or the manner seven described above, the transmission resource may be selected according to measurement information according to one of the following manners.

Mode one: in Step 2, the UE performing transmission resource selection determines a threshold of PSSCH-RSRP from other UEs according to the modulation scheme to be used. Note that in Step 2 of the prior art, the threshold of PSSCH-RSRP is related to V2X traffic priority. The invention increases the modulation mode based on the existing factors affecting the threshold.

Preferably, when the UE performing transmission resource selection will use QPSK or 16QAM modulation, the threshold of PSSCH-RSRP is thr_rsrp1, and when the UE performing transmission resource selection will use 64QAM modulation, the threshold of PSSCH-RSRP is thr_rsrp2. Wherein thr_rsrp2 is less than or equal to thr_rsrp1, thereby further protecting 64QAM based data transmission. The threshold thr_rsrp2 may be configured by higher layer signaling, or may be a value of standard definition thr_rsrp1, thr_rsrp2 being offset by Δ1 with respect to thr_rsrp1, such as thr_rsrp2=thr_rsrp1 (dB) +Δ1, e.g., Δ1 is equal to-3 (dB). Δ1 may be high-level signaling configured, preconfigured, or predefined.

Mode two: UE for selecting transmission resources, in Step 2, after excluding resources above a specific threshold PSSCH-RSRP above the specific threshold, the proportion of the remaining resources to the total resources in the resource selection window must not be lower than the specific threshold Thr _{_step2_ratio} . The characteristic threshold is determined according to a modulation mode to be adopted by the UE performing the transmission resource selection.

Further, the UE performing transmission resource selection, in Step3, the proportion of the partial resources to the total resources in the resource selection window must not be lower than a specific threshold Thr _{_step3_ratio} . The characteristic threshold is determined according to a modulation mode to be adopted by the UE performing the transmission resource selection.

Preferably, the specific threshold Thr of step2 is assumed to be the specific threshold Thr when the UE performing transmission resource selection will employ QPSK or 16QAM modulation scheme _{_step2_ratio} ＝Thr _{_step2_ratio1} The st isSpecific threshold Thr of ep3 _{_step3_ratio} ＝Thr _{_step3_ratio1} . The specific threshold Thr of step2 is the threshold when the UE for selecting transmission resources will employ 64QAM modulation scheme _{_step2_ratio} ＝Thr _{_step2_ratio2} A specific threshold Thr of step3 _{_step3_ratio} ＝Thr _{_step3_ratio2} . For example, thr _{_step2_ratio2} Less than Thr _{_step2_ratio1} ，Thr _{_step3_ratio2} Less than Thr _{_step3_ratio1} The interference level of the candidate resources can thus be further reduced.

Preferably, the method can be used in combination with the method I and the method II. For example, when the UE performing the transmission resource selection is to employ 64QAM modulation scheme, PSSCH-RSRP thresholds Thr-RSRP, thr in step2 _{_step2_ratio} Thr in step3 _{_step3_ratio} Both below the threshold where the UE will employ QPSK or 16QAM modulation. Mode three: in Step2, the UE performing transmission resource selection determines the threshold of the PSSCH-RSRP from other UEs according to the modulation scheme of the PSCCH instruction received from other UEs. Preferably, when the UE for selecting the transmission resource adopts QPSK or 16QAM modulation mode, the threshold of PSSCH-RSRP is Thr_rsrp1, and when the other UE adopts 64QAM modulation mode, the threshold of PSSCH-RSRP is Thr_rsrp3. Wherein thr_rsrp3 is less than or equal to thr_rsrp1, thereby further protecting 64QAM based data transmission. The threshold thr_rsrp3 may be configured by higher layer signaling, or may be a value of standard definition thr_rsrp1, thr_rsrp3 being offset by Δ2 with respect to thr_rsrp1, such as thr_rsrp3=thr_rsrp1 (dB) +Δ2, e.g., Δ2 is equal to-3 (dB). Δ2 may be higher layer signaling configured, preconfigured, or predefined.

Preferably, the first mode and the third mode can be combined. In Step 2, the UE performing transmission resource selection determines the threshold of the psch-RSRP from other UEs according to the adjustment mode to be adopted by the UE performing transmission resource selection and the modulation mode of the PSCCH instruction received from other UEs. Preferably, when the UE performing transmission resource selection uses QPSK or 16QAM modulation, the threshold of PSSCH-RSRP is thr_rsrp1, and the value of the threshold thr_rsrp4 of PSSCH-RSRP may be the same or different, corresponding to four cases of whether the UE performing transmission resource selection uses 64QAM and whether the received PSCCH instruction from other UEs has modulation of 64 QAM. Wherein thr_rsrp4 is less than or equal to thr_rsrp1, thereby further protecting 64QAM based data transmission. The threshold thr_rsrp4 may be configured with higher layer signaling or may be a value of standard definition thr_rsrp1, thr_rsrp4 being offset by Δ3 with respect to thr_rsrp1, such as thr_rsrp4=thr_rsrp1 (dB) +Δ3, e.g., Δ3 is equal to-3 (dB). Δ3 may be high-level signaling configured, preconfigured, or predefined.

Preferably, the first mode, the second mode and the third mode can be combined.

By the method, the threshold is determined according to the modulation mode, so that interference suffered by PSSCH when 64QAM transmission is adopted is reduced.

For a second class V2X UE, the modulation order is determined according to one of the following ways:

mode one: the second V2X UE reads MCS indication information in PSCCH from other UEs, and determines a modulation mode Q ' =Q ' according to a MCS-TBS table ' _m 。

Preferably, the MCS-TBS table is shown in Table 2.

Preferably, the MCS-TBS table, I _MCS As shown in table 2, the values=0 to 28 correspond to I of table 2 _MCS ＝0～28，I _MCS The terms=29 to 31 are defined as modulation coding schemes supporting 64QAM or 256QAM and TBS index to support higher modulation coding rates.

Preferably, the MCS-TBS table, I _MCS =0 to 28 as shown in table 2, I _MCS =29 to 31 can be defined as the same as I in table 2 _MCS Modulation and coding scheme and TBS index same as those of =21 to 23, i.e., I in table 2 _MCS Three lines of =21 to 23 are copied to I _MCS ＝29～31。

Preferably, the MCS-TBS table, I _MCS =0 to 20, 24 to 28 as shown in table 2, I _MCS =21 to 23 defined as the sum of I in table 2 _MCS =21 to 23 phasesThe same TB index, but with a modulation order of 4, i.e. 16QAM. I _MCS =29 to 31 can be defined as the same as I in table 2 _MCS The modulation and coding scheme and TBS index are the same as those of=21 to 23, i.e., the modulation order is 6 (64 QAM). The advantage of this is that the second class V2X UEs can transmit I _MCS =21 to 23, and realizes that a large TB is still transmitted in the low-order modulation scheme, i.e., in the 16QAM scheme. By transmitting the PSSCH twice, the first type V2X UE or the second type V2X UE can demodulate the PSSCH. Because the V2X UE of the first class is receiving I _MCS When=21 to 23, the modulation scheme is also determined according to 16 QAM. In this way, the SCIX sent by the second class V2X UE is made post-compatible. If the second V2X UE wants to use a larger modulation scheme, such as 64QAM, and the same TBS as the LTE system, it can transmit I _MCS =29 to 31. V2X UE of the first class detects I _MCS When=29 to 31, demodulation of PSSCH is abandoned.

Mode two: the second class V2X UEs read MCS indication information in PSCCHs from other UEs. According to Table 2, I in MCS indication information of PSCCH _MCS When Th_mcs is not more than, modulation scheme Q ' =min (4, Q ' ' _m ) When I _MCS >When th_mcs, Q '=q' _m . Where th_mcs is predefined by a standard, e.g. th_mcs=23, or th_mcs=24.

Mode three: if the second type V2X UE can distinguish whether the received PSCCH is from the first type V2X UE or the second type V2X UE, if the received PSCCH is from the second type V2X UE, determining a modulation scheme Q ' =q ' according to table 2 and MCS indication information of the PSCCH ' _m The method comprises the steps of carrying out a first treatment on the surface of the If the received PSCCH comes from the V2X UE of the first class, when the MCS of the PSCCH indicates I in the information _MCS When Th_mcs is not more than, modulation scheme Q ' =min (4, Q ' ' _m ) When I _MCS >When th_mcs, Q '=q' _m . Where th_mcs is standard predefined, e.g., th_mcs=24.

The present embodiment does not define how the UE distinguishes what type of V2X UE the received PSCCH is from. For example, in SCI transmitted by the second type V2X UE, the MCS mapping method may be indicated by one bit of the reserved bits, i.e., operating in the MCS mapping manner of the first type V2X UE or in the MCS mapping manner of the second type V2X UE.

Step 103: the UE determines whether to further demodulate the PSSCH scheduled by SCI X according to the SCI X modulation coding indication information.

Embodiment two:

in general, when a data packet is initially transmitted, if the code rate exceeds 0.93, the UE may not properly demodulate the data packet, and thus, the UE may not demodulate the data packet. In the LTE Rel-8 system, when the transport block size is defined (tables 7.1.7.2.1-1 to 7.1.7.2.5-1 in 3GPP TS 36.213), I _TBS When=0 to 25, the number of resources mapped by the TB is assumed to be 120 Resources (REs) per PRB, _S I _BT when=26, the number of resources mapped by the TB is assumed to be 136 Resources (REs) per PRB, so the effective coding rate determined according to the TBs in the table and the number of physical resources mapped by the TB does not exceed 0.93. In the V2X communication in LTE Rel-14/15, since the first symbol is used as AGC adjustment, the 3 rd, 6 th, 9 th, and 12 th symbols are mapped to demodulation reference signals (DM-RS), and the last symbol is used as Gap (Gap), the symbols actually available for data effective transmission are 8 symbols, i.e., the number of resources mapped by the TB is that each PRB contains only 96 Resources (REs). Thus, if the MCS table (Table 2) and TBS table (Table 7.1.7.2.1-1 in 3GPP TS 36.213) of LTE Rel-8 are reused, part I will occur _MCS The effective code rate exceeds 0.93. In order to avoid an effective coding rate exceeding 0.93, only the remaining I can be used _MCS So that the flexibility of supportable TBSs is impaired. Especially after 64QAM support, e.g. in Table 2, I _MCS >23 all I _MCS And cannot be used. Similarly, in V2X communication in LTERel-14/15 or NR, one V2X transmission may occupy a shorter time resource, for example, may occupy only one slot, i.e. 7 symbols, and if half of the symbols are used as AGC adjustment, half of the symbols are used as Gap, and the 3,6 th symbols map demodulation reference signals (DM-RS), i.e. the number of resources mapped by the TB is that each PRB contains only 48 Resources (REs). Also, in future communication systems, one V2X transmission may occupy shorter time resources. If reuse of MCS of LTE Rel-8Table (Table 2) and TBS Table (Table 7.1.7.2.1-1 in 3GPP TS 36.213) more I's will occur _MCS The effective code rate exceeds 0.93. To avoid available I _MCS The number is reduced, and the present embodiment proposes that the TBS may be determined by one of the following ways:

mode one of determining TBS: determining the number of PRBs occupied by PSSCH scheduled by PSCCH as N according to the information of 'primary transmission and retransmitted frequency domain resource position' indicated in the received PSCCH _P ′ _RB And when looking up TBS according to table 7.1.7.2.1-1 in 3gpp ts36.213, according to N _PRB Determining, wherein,/>

preferably, β=0.75, or β=0.8, or β=2/3, or β is a non-negative number of the higher layer configuration of not more than 1.

Preferably, the beta used may be different for PSSCHs having different transmission time lengths. For example, when the length of time resource occupied by the transmitted PSSCH is 1ms, β=0.75 is used, and when the length of time resource occupied by the transmitted PSSCH is 0.5ms, β=0.375 is used. Alternatively, when the time resource degree occupied by the PSSCH of the transmission is 1ms, β=1 is used, i.e. the number of PRBs occupied by the PSSCH of the PSCCH schedule is determined to be N' _PRB And when looking up TBS according to table 7.1.7.2.1-1 in 3gpp TS36.213, according to N' _PRB Determining; when the time resource degree occupied by the transmitted PSSCH is 0.5ms, the used beta=0.5,

for example, I _MCS When=25, determine I according to table 2 _TBS =23. Assuming that the number of PRBs indicated by the received PSCCH is 40, the prior art is: according to 40 PRBs, look up table 7.1.7.2.1-1 in 3GPP TS36.213, determine TBS as 22920, effective coding rate>0.93. In a first aspect of the present embodiment, the following is: first determineFrom 32 PRBs, look up table 7.1.7.2.1-1 in 3GPP TS36.213, determine TBS as 18336. At this time, the effective encoding speed is lower than 0.93.

Mode two of determining TBS: when I _MCS >When Th_mcs1 is used, according to the information of 'primary transmission and retransmission frequency domain resource position' indicated in the received PSCCH, the PRB number occupied by PSSCH scheduled by PSCCH is determined to be N _P ′ _RB And when looking up TBS according to table 7.1.7.2.1-1 in 3gpp TS 36.213, according to N _PRB Determining, wherein,when I _MCS When the number of PRBs occupied by PSSCH scheduled by PSCCH is less than or equal to Th_mcs1, determining that the number of PRBs occupied by PSSCH scheduled by PSCCH is N according to the information of 'primary transmission and frequency domain resource position' of retransmission indicated in received PSCCH _P ′ _RB And when looking up TBS according to table 7.1.7.2.1-1 in 3gpp TS 36.213, according to N _P ′ _RB And (5) determining.

Preferably, th_mcs1 is defined independently, or configured independently, for different PSSCH transmission time lengths.

Preferably, th_mcs1 is standard predefined. One implementation is that th_msc1 of this embodiment is equal to th_mcs of embodiment one. In another implementation manner, th_msc1 of the present embodiment and th_mcs of the first embodiment are defined respectively. Of course, it is also possible that the standard defines only th_msc1 or th_msc, or neither.

Preferably, the standard predefined Th_mcs1 is the minimum I corresponding to 64QAM _MCS For example, th_mcs1=21.

Preferably, when the length of time resource occupied by PSSCH transmitted is 1ms, th_mcs1 is the minimum I corresponding to 64QAM _MCS When the length of time resources occupied by the transmitted PSSCH is less than 1ms, th_mcs1= -1, i.e. for all MCSs,

preferably, when the length of time resource occupied by PSSCH transmitted is 1ms, the predefined standard Th_msc1 is equal to 18. The beneficial effect of this is that all the 64QAM corresponding I _MCS And I in 16QAM which may result in an effective code rate greater than 0.93 _MCS N 'in Table 7.1.7.2.1-1' _PRB Weighting is performed so that N 'after weighting' _PRB (i.e. N _PRB ) The effective code rate of the corresponding TBS is less than or equal to 0.93.

Preferably, th_msc1 is determined for the number of PRBs possibly occupied by PSSCH, so that all the corresponding I of 64QAM _MCS And I in 16QAM which may result in an effective code rate greater than 0.93 _MCS In N' _PRB After weighting, the effective coding rate of the corresponding TBS is less than or equal to 0.93.

Preferably, when the length of the time resource occupied by the transmitted PSSCH is 1ms, the setting of the standard predefined th_msc1 is determined according to the maximum transmission times of the PSSCH, for example, the effective coding rate after combining two PSSCH transmissions is greater than the minimum MCS index corresponding to 0.93. Wherein, when determining th_msc1, the effective coding rate is calculated, one way is according to modulation scheme Q ' =min (4, Q ' ' _m ) Calculated by the method. This has the advantage of being the same as the Rel-14V2X UE calculation method. Another implementation way is that according to the modulation mode Q ' =Q ' ' _m Calculated by the method. For example, if calculated in 16QAM, th_msc1 is equal to 23. The beneficial effect of this is that I _MCS <Th_msc1, TBS is determined in the same manner as Rel-14V2X, i.e., N 'indicated by PSCCH' _PRB Determining TBS so that the first V2X UE can demodulate PSSCH scheduled PSCCH sent by the second V2X UE; when I _MCS When not less than Th_msc1, N 'indicated by PSCCH' _PRB The TBS is determined after weighting, and because the TBS determined by Rel-14V2X at this time has the corresponding coding efficiency exceeding 0.93, the PSSCH cannot be solved by the V2X UE of the first class. And for the second V2XUE, the N 'can be used for' _PRB The TBS is determined after weighting so that the second class V2X UEs can demodulate the PSSCH correctly. For another example, if calculated in terms of 64QAM, th_msc1 is equal to 26. Note that the above values are merely exemplary examples. Other values are possible depending on the system design for achieving the above-described objectives.

Preferably, for PSSCH with different transmission time lengths, the β used may be different.

Preferably, the value of th_msc1 is not standard predefined, but the value of th_msc1 is determined to be standard predefined. For example, as described above, the value of th_msc1 is determined according to the maximum number of transmissions of the PSSCH, for example, the minimum MCS index corresponding to the effective coding rate after combining the two transmissions is greater than 0.93. When the number of PRBs occupied by the actually scheduled PSSCH is different, the value of th_msc1 may be different. Alternatively, the value of th_msc1 may be different when the length of time occupied by the actually scheduled PSSCH is different.

Mode three of determining TBS: if the V2X UE can distinguish whether the received PSCCH is from a first type V2X UE or a second type V2X UE, then:

1) If the received PSCCH comes from the V2X UE of the first class, determining that the number of PRBs occupied by PSSCH scheduled by the PSCCH is N 'according to the information of' primary transmission and frequency domain resource position of retransmission 'indicated in the received PSCCH' _PRB . When looking up TBS according to Table 7.1.7.2.1-1 in TS 36.213, it is found according to N' _PRB And (5) determining.

2) If the received PSCCH comes from the second V2X UE, determining that the number of PRBs occupied by PSSCH scheduled by the PSCCH is N 'according to the information of' primary transmission and frequency domain resource position of retransmission 'indicated in the received PSCCH' _PRB . When looking up TBS according to Table 7.1.7.2.1-1 in TS 36.213, it is found according to N _PRB Determining, wherein,alternatively, if the received PSCCH is from a second class V2X UE, when I _MCS >When Th_mcs1 is used, according to the information of ' primary transmission and retransmission frequency domain resource position ' indicated in the received PSCCH, the PRB number occupied by PSSCH scheduled by PSCCH is determined to be N ' _PRB And when looking up TBS according to table 7.1.7.2.1-1 in 3gpp TS 36.213, according to N _PRB Determining, wherein->When I _MCS When the Th_mcs1 is not more thanDetermining that the number of PRBs occupied by PSSCH scheduled by PSCCH is N 'according to the information of' primary transmission and frequency domain resource position of retransmission 'indicated in received PSCCH' _PRB And when looking up TBS according to table 7.1.7.2.1-1 in 3gpp TS 36.213, according to N' _PRB And (5) determining.

This embodiment may be implemented in steps 201-203.

Step 201: the UE detects PSCCH in SCI X format sent by other UEs.

Step 202: the UE determines the TBS based on the "modulation coding scheme" indication information (MSC bit field) of SCI X and the "frequency domain resource location for initial transmission and retransmission" information.

Preferably, for the second class V2X UE, the TBS is determined according to one of the first to third modes of the present embodiment.

Step 203: the UE demodulates the PSSCH according to the SCI X information.

Embodiment III: in the V2X communication in LTE Rel-14/15, since the first symbol is used as AGC adjustment, the 3 rd, 6 th, 9 th, and 12 th symbols are mapped to demodulation reference signals (DM-RS), and the last symbol is used as Gap (Gap), the symbols actually available for data effective transmission are 8 symbols, i.e., the number of resources mapped by the TB is that each PRB contains only 96 Resources (REs). Thus, if the MCS table (Table 2) and TBS table (Table 7.1.7.2.1-1 in 3GPP TS 36.213) of LTE Rel-8 are reused, part I will occur _MCS The effective coding rate exceeds 0.932. In order to avoid an effective coding rate exceeding 0.932, only the remaining I can be used _MCS So that the flexibility of supportable TBSs is impaired. Especially after 64QAM support, e.g. in Table 2, I _MCS >23 all I _MCS And cannot be used. Similarly, in V2X communication in LTE Rel-14/15 or NR, one V2X transmission may occupy a shorter time resource, for example, may occupy only one slot, i.e. 7 symbols, and if half of the symbols are used as AGC adjustment, half of the symbols are used as Gap, and the 3,6 th symbols map demodulation reference signals (DM-RS), i.e. the number of resources mapped by the TB is that each PRB contains only 48 Resources (REs). And, in future communication systems, one V2X transmission may occupyShorter time resources. If the MCS table (Table 2) and TBS table (Table 7.1.7.2.1-1 in 3GPP TS 36.213) of LTE Rel-8 are reused, more I will occur _MCS The effective coding rate exceeds 0.932. To avoid available I _MCS The number decreases, and thus the spectral efficiency decreases, the present embodiment proposes that TBS and modulation order can be determined by:

for transmitting UE, determining the number N 'of PRBs for PSSCH transmission according to higher layer indication' _PRB According toDetermining an effective PRB number N _PRB The method comprises the steps of carrying out a first treatment on the surface of the Determining modulation coding mode index I of PSSCH according to high-layer indication _MCS Determining TBS index I according to mapping table from MCS index corresponding to beta to TBS index and modulation order _TBS And modulation order. Then according to the specific TBS index and the mapping relation from PRB number to TBS, determining the TBS value, wherein the adopted TBS index value is I _TBS The number of PRBs used is the effective number of PRBs N _PRB In the LTE system, the mapping relationship between the specific TBS index and the PRB number to the TBS may be defined by a standard, and preferably, the mapping relationship between the TBS index and the PRB number to the TBS determined in the table 7.1.7.2.1-1 in 3gpp TS 36.213 may be used.

For receiving UE, determining the number of PRBs occupied by PSSCH scheduled by PSCCH as N 'according to the information of' primary transmission and frequency domain resource position of retransmission 'indicated in received PSCCH' _PRB According toDetermining an effective PRB number N _PRB The method comprises the steps of carrying out a first treatment on the surface of the Determining a modulation coding mode index of PSSCH scheduled by PSCCH according to the received 'modulation coding mode' indicated in the PSCCH, and I _MCS Determining TBS index I according to mapping table from MCS index corresponding to beta to TBS index and modulation order _TBS And modulation order. Then according to the specific TBS index and the mapping relation from PRB number to TBS, determining the TBS value, wherein the adopted TBS index value is I _TBS The number of PRBs used is the effective number of PRBs N _PRB In the LTE system, the mapping relationship between the specific TBS index and the PRB number to the TBS may be defined by a standard, and preferably, the mapping relationship between the TBS index and the PRB number to the TBS determined in the table 7.1.7.2.1-1 in 3gpp TS 36.213 may be used.

According to one implementation of this embodiment, β may have a value of 0.981,0.98 or 0.925. The adoption of beta=0.981 can increase the maximum spectrum efficiency achieved by the PSSCH, and can avoid excessive reduction of the lowest code rate of the PSSCH; β=0.98 can obtain similar advantageous effects as β=0.981, but the number of bits of β can be further reduced. β=0.925 can obtain the same maximum PSSCH spectral efficiency as the above two values, and the average spectral efficiency of the PSSCH is increased relative to the former two, but the lowest code rate of the PSSCH is lower than the former two.

The MCS index to TBS index mapping table corresponding to β=0.981, β=0.98 or β=0.925 is:

according to another implementation of this embodiment, β may have a value of 0.872 or 0.836. With β=0.872, a higher maximum spectral efficiency of the PSSCH, a higher average spectral efficiency of the PSSCH and more available I can be obtained simultaneously _MCS A number; while β=0.836 can maximize the average spectral efficiency of the PSSCH.

The MCS index to TBS index mapping table corresponding to β=0.872 or β=0.836 is:

according to yet another implementation of the present embodiment, β may have a value of 0.719. Beta=0.719 can maximize the available I _MCS A number.

The MCS index to TBS index mapping table corresponding to β=0.719 is:

embodiment four:

in a communication system, if the transmitted signals are modulated differently, the required transmit power is different to achieve the same probability of correct reception. For example, when the modulation order is higher, the required transmit power is also relatively higher to achieve the same coverage. At the same time, the transmit power required to achieve the same probability of correct reception is also related to the number of transmissions. For example, if the two transmissions combine with at least 3dB gain over one transmission, then the transmit power required for both transmissions is not greater than half that of a single transmission in order to achieve the same coverage.

Thus, in this embodiment, the power spectral density (PSD, power spectrum density) of the PSCCH in the format SCI X and the power spectral density PSD of the PSCCH scheduled by the PSCCH should be determined according to the PSSCH and/or modulation scheme of the PSCCH. For example, the power of the PSSCH may be determined first, and then the power of the PSCCH may be determined based on the PSD offset from the PSSCH. The PSD offset is determined according to a PSSCH and/or PSCCH modulation mode.

The specific implementation can be determined according to one of the following modes one to three:

mode one: the PSD offset between PSSCH and PSCCH is independent of the PSSCH and PSCCH modulation scheme, but the total PSSCH and PSCCH power increases with the PSSCH and/or PSCCH modulation scheme.

For example, for a V2X UE operating in mode three, the total power a of PSSCH and PSCCH is:

A＝10log ₁₀ (M _PSSCH +10 ^γ ×M _PSCCH )+P _{O_PSSCH，3} +α _PSSCH，3 ·PL+10log10(η) (1)

where η is a parameter related to the modulation scheme. For example, η=q _m /Q' _mPSCCH ，Q' _m For PSSCH modulation, Q' _mPSCCH Is the modulation mode of PSCCH. For example, if the modulation scheme of PSCCH is QPSK, Q' _mPSCCH ＝2。

Or,wherein f (Q' _m ) In Q' _m As a function of the variables, as Q' _m Is increased by an increase in (a).

Or,wherein X is Q' _m Related parameters, X follows Q' _m Monotonically increasing Ks is a parameter configured by higher layers, e.g. ks=0, i.e. the total power a of PSSCH and PSCCH does not vary with modulation scheme, if Ks > 0, the total power a varies with Q' _m Monotonically increasing.

Where γ is the PSD offset of the PSSCH and PSCCH defined by the standard, or parameters of the higher layer configuration. For example, γ=0.3. In the formula (1), M _PSSCH Representing the number of RBs occupied by PSSCH, M _PSCCH Representing the number of RBs occupied by PSCCH, P _{O_PSSCH,3} And alpha _PSSCH,3 Parameters configured for higher layers, PL is path loss, P _CMAX Is the maximum transmit power.

Then the power of PSCCH and PSCCH is:

it can be seen that the power ratio P of PSCCH and pscsch _PSCCH /P _PSSCH ＝10log10(10 ^γ M _PSCCH /M _PSSCH ) Independent of the ratio of the modulation scheme.

Mode two: the PSD offset of PSSCH and PSCCH is related to the relation between PSSCH and PSCCH modulation scheme, and the total power of PSSCH and PSCCH increases with the increase of PSSCH and/or PSCCH modulation scheme.

For example, for a V2X UE operating in mode four, the total power a of PSSCH and PSCCH is, if the higher layer is configured with the maximum transmission power (maxTxpower), then:

A＝min{P _CMAX ,P _{MAX_CBR} ，10log ₁₀ (M _PSSCH +10 ^γ-λ ×M _PSCCH )+P _{O_PSSCH,4} +α _PSSCH,4 PL (2) otherwise,

A＝min{P _CMAX ,10log ₁₀ (M _PSSCH +10 ^γ-λ ××M _PSCCH )+P _{O_PSSCH,4} +α _PSSCH,4 ·PL} (3)

in the formulas (2) and (3), M _PSSCH Representing the number of RBs occupied by PSSCH, M _PSCCH Representing the number of RBs occupied by PSCCH, P _{O_PSSCH,4} And alpha _PSSCH,4 Parameters configured for higher layers, PL is path loss, P _{MAX_CBR} To a value determined according to CBR (channel busy ratio), P _CMAX Is the maximum transmit power.

Assuming that the power ratio of PSSCH to PSCCH is lambda, lambda is a parameter related to modulation scheme, along with Q' _m And becomes smaller as the number of (a) increases. For example, λ= (10 log10 (Q' _m /Q' _mPSCCH ) A) or, alternatively,wherein f (Q' _m ) In Q' _m As a function of variables, e.g. when Q' _m When=6, λ=log10 (3).

Then the power of the PSSCH is:

the power of the PSCCH is:

mode three: PSCCH PSD and/or PSSCH PSD is/are determined according to PSCCH modulation mode and/or PSSCH modulation mode.

For example, the power of the PSCCH is:

η ₁ is a parameter related to the PSCCH modulation scheme. For example, eta ₁ ＝Q _mPSCCH /2. It can be seen that if PSCCH employs QPSK, P _PSCCH There is no power variation introduced by the modulation scheme. When 16QAM is used for PSCCH, then P _PSCCH P relative to QPSK _PSCCH There is a 3dB delta.

Similarly, the power of the PSSCH is:

η ₂ is a parameter related to the PSSCH modulation scheme. For example, eta ₂ ＝Q _m And/2, or alternatively,wherein f (Q' _m ) In Q' _m As a function of the variables, as Q' _m Is increased by an increase in (a). For example, when PSSCH employs 64QAM, η ₂ =3, and η when QPSK or 16QAM is used ₂ =1. It can be seen that if PSSCH employs QPSK, P _PSSCH There is no power variation introduced by the modulation scheme. When PSSCH adopts 64QAM, P at this time _PSSCH P relative to QPSK _PSSCH There is a 4.7dB delta.

The application provides a user equipment, comprising: the system comprises a control information detection module, a parameter determination module, a transmission resource selection module and a demodulation module, wherein:

The application also provides a user equipment, which is characterized by comprising: a transmit power determination module and a transmit module, wherein:

mode three: PSD of PSSCH is determined according to modulation mode of PSSCH;

Those skilled in the art will appreciate that the present application includes apparatuses related to performing one or more of the operations described herein. These devices may be specially designed and constructed for the required purposes, or may comprise known devices in general purpose computers. These devices have computer programs stored therein that are selectively activated or reconfigured. Such a computer program may be stored in a device (e.g., a computer) readable medium or any type of medium suitable for storing electronic instructions and respectively coupled to a bus, including, but not limited to, any type of disk (including floppy disks, hard disks, optical disks, CD-ROMs, and magneto-optical disks), ROMs (Read-Only memories), RAMs (Random Access Memory, random access memories), EPROMs (Erasable Programmable Read-Only memories), EEPROMs (Electrically Erasable Programmable Read-Only memories), flash memories, magnetic cards, or optical cards. That is, a readable medium includes any medium that stores or transmits information in a form readable by a device (e.g., a computer).

It will be understood by those within the art that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by computer program instructions. Those skilled in the art will appreciate that the computer program instructions can be implemented in a processor of a general purpose computer, special purpose computer, or other programmable data processing method, such that the blocks of the block diagrams and/or flowchart illustration are implemented by the processor of the computer or other programmable data processing method.

Those of skill in the art will appreciate that the various operations, methods, steps in the flow, acts, schemes, and alternatives discussed in the present invention may be alternated, altered, combined, or eliminated. Further, other steps, means, or steps in a process having various operations, methods, or procedures discussed herein may be alternated, altered, rearranged, disassembled, combined, or eliminated. Further, steps, measures, schemes in the prior art with various operations, methods, flows disclosed in the present invention may also be alternated, altered, rearranged, decomposed, combined, or deleted.

The foregoing description of the preferred embodiments of the application is not intended to be limiting, but rather to enable any modification, equivalent replacement, improvement or the like to be made within the spirit and principles of the application.

Claims

1. A method performed by a user equipment, UE, in a communication system, comprising:

receiving a bypass control channel PSCCH sent by other UE, wherein the PSCCH comprises bypass control information SCI;

based on the frequency domain resource in the SCIInformation related to source position, determining that the number of PRBs occupied by a bypass data channel PSSCH scheduled by PSCCH is N _P ′ _RB ；

Based on the TBS table of the transmission block size, according to TBS index I _TBS And N _PRB A corresponding TBS is determined, wherein,and β=0.8.

2. The method according to claim 1, characterized in that: the I is _TBS Is based on the modulation coding scheme index I in the SCI _MCS And modulation and transport block size MCS-TBS table.

3. The method according to any one of claims 1-2, wherein: i in the MCS-TBS table _MCS The section=29-31 is a modulation coding scheme supporting 64QAM and TBS index.

4. The method according to claim 1, characterized in that: further comprises:

Step B, according to the SCI, determining parameter information of PSSCH scheduled by the SCI;

step C, determining whether to receive and measure the demodulation reference channel receiving power PSSCH-RSRP of PSSCH scheduled by SCI and/or the average receiving energy S-RSSI of the residual resources according to the parameter information of PSSCH, and selecting the transmitting resources according to the measurement information;

and D, receiving the PSSCH scheduled by the SCI according to the SCI, and determining whether to demodulate the PSSCH according to the SCI.

5. The method according to claim 4, wherein:

the step B comprises the following steps: the first V2XUE is based on the value I of MSC bit domain of SCI modulation coding mode _MCS Determining the modulation mode of PSSCH of other UE, and correspondingly, implementing the step C and the step D by the V2XUE of the first type according to at least one of the following modes:

mode one: if I _MCS >20, the first V2XUE measures PSSCH-RSRP and/or S-RSSI of the scheduled PSSCH according to the parameter information of the PSCCH, selects transmission resources according to the measurement information, and demodulates or skips demodulating the PSSCH scheduled by the PSCCH;

Mode four: if I _MCS >20, when modulation scheme Q ' =min (4, Q ' ' _m ) When=4, the V2X UE of the first class determines the expected number of PSSCHs scheduled by the PSCCHIf the effective channel coding rate is larger than a set threshold Thc, the V2X UE of the first type measures PSSCH-RSRP and/or S-RSSI of the scheduled PSSCH according to parameter information of the PSCCH, selects transmission resources according to the measured information, and demodulates or skips demodulating the PSSCH scheduled by the PSCCH; when modulation scheme Q ' =min (4, Q ' ' _m ) When the calculated effective channel coding rate is less than or equal to a set threshold Thc, the V2X UE of the first class measures PSSCH-RSRP and/or S-RSSI of the scheduled PSSCH according to parameter information of the PSCCH, selects transmission resources according to the measurement information, and demodulates the PSSCH scheduled by the PSCCH;

wherein Q' _m According to I _MCS And (5) determining a modulation mode.

6. The method according to claim 5, wherein:

the step B comprises the following steps: the first V2X UE determines the resource reservation information of PSSCH of other UE according to the resource reservation bit field of SCI, and correspondingly, the first V2X UE realizes the step C and the step D according to the following modes:

7. The method according to claim 5 or 6, characterized in that:

if the V2X UE of the first class judges that the TBS exceeds the maximum UE capacity according to the MCS information of the received PSCCH, the V2X UE of the first class measures PSSCH-RSRP and/or S-RSSI of the scheduled PSSCH according to the information of the PSCCH, selects transmission resources according to the measurement information, and demodulates or skips demodulating the PSSCH scheduled by the PSCCH.

8. The method according to any one of claims 4 to 6, wherein:

the step B comprises the following steps: the second V2X UE determines the effective channel coding rate of PSSCH scheduled by PSCCH of other UE according to SCI;

the second class V2X UE implements said steps C and D in at least one of the following ways:

9. The method as recited in claim 4, further comprising: the TBS is determined as follows:

when I _MCS >When Th_mcs1 is used, according to the frequency domain resource position information indicated in the received PSCCH, the PRB number occupied by PSSCH scheduled by PSCCH is determined to be N _P ′ _RB And according to N _PRB A look-up table determines the TBS, wherein,when I _MCS When the number of PRBs occupied by PSSCH scheduled by PSCCH is less than or equal to Th_mcs1, determining that the number of PRBs occupied by PSSCH scheduled by PSCCH is N according to the received frequency domain resource position information indicated in the PSCCH _P ′ _RB And according to N _P ′ _RB Table lookup to determine TBS; th_mcs1 is a preset value;

for UEs that can distinguish whether the received PSCCH is from a first type V2X UE or a second type V2X UE: if the received PSCCH comes from the V2X UE of the first class, according to the received PSCC The frequency domain resource position information indicated in H determines that the number of PRBs occupied by PSSCH scheduled by PSCCH is N _P ′ _RB And according to N _P ′ _RB Table lookup to determine TBS; if the received PSCCH comes from the second V2X UE, determining that the number of PRBs occupied by PSSCH scheduled by the PSCCH is N according to the frequency domain resource position information indicated in the received PSCCH _P ′ _RB And according to N _PRB A look-up table determines the TBS, wherein,alternatively, if the received PSCCH is from a second class V2X UE, when I _MCS >When Th_mcs1 is used, according to the received frequency domain resource position information indicated in PSCCH, determining that the number of PRBs occupied by PSSCH scheduled by PSCCH is N _P ′ _RB And according to N _PRB Determining TBS by looking up a table, wherein->When I _MCS When the number of PRBs occupied by PSSCH scheduled by PSCCH is less than or equal to Th_mcs1, determining that the number of PRBs occupied by PSSCH scheduled by PSCCH is N according to the received frequency domain resource position information indicated in the PSCCH _P ′ _RB And according to N _P ′ _RB The TBS is determined by looking up a table.

10. The method according to claim 9, wherein:

for the manner of determining TBS, β=0.75, or β=0.8, or β=2/3, or β is a configured non-negative number of no more than 1.

11. The method of claim 9, wherein for the manner in which the TBS is determined:

th_mcs1 is the minimum I corresponding to 64QAM _MCS ；

Alternatively, th_msc1=18;

Or, for the PRB number possibly occupied by PSSCH, respectively determining corresponding Th_msc1 to enable all the corresponding I of 64QAM _MCS And possibly result in a large effective code rate in 16QAMI at 0.93 _MCS At N _P ′ _RB After weighting, the effective coding rate of the corresponding TBS is smaller than or equal to 0.93;

alternatively, th_msc1=23.

12. The method as recited in claim 1, further comprising:

mode three: PSD of PSSCH is determined according to modulation mode of PSSCH.

13. A user device, comprising:

a memory storing computer-executable instructions;

a processor, wherein the computer executable instructions, when executed by the processor, cause the processor to perform the method of any of claims 1 to 2.