CN114175693B

CN114175693B - Resource configuration for feedback channel for device-to-device communication

Info

Publication number: CN114175693B
Application number: CN201980098927.4A
Authority: CN
Inventors: 刘勇; 李栋; T·维尔德斯彻克; 谭钧
Original assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Priority date: 2019-07-30
Filing date: 2019-07-30
Publication date: 2024-12-13
Anticipated expiration: 2039-07-30
Also published as: CN114175693A; WO2021016882A1

Abstract

Embodiments of the present disclosure relate to devices, methods, apparatuses, and computer-readable storage media for resource allocation of feedback channels for device-to-device communications. In an example embodiment, if device-to-device data is to be transmitted over a device-to-device data channel to a second terminal device during a transmission period, the first terminal device selects a sub-channel from a plurality of sub-channels of the device-to-device data channel during the transmission period. The first terminal device selects a feedback period from a plurality of feedback periods on the device-to-device feedback channel based on the transmission period and a predetermined delay range between the device-to-device data channel and the device-to-device feedback channel. The first terminal device also sends an indication of the feedback period to the second terminal device to enable the second terminal device to send an acknowledgement of the device-to-device data over the device-to-device feedback channel for the feedback period.

Description

Resource configuration for feedback channels for device-to-device communication

Technical Field

Embodiments of the present disclosure relate generally to the field of communications and, in particular, relate to devices, methods, apparatuses, and computer-readable storage media for resource configuration of feedback channels for device-to-device communications.

Background

New Radio (NR) internet of vehicles (V2X) is being developed to provide advanced V2X services in NR systems. In Long Term Evolution (LTE) V2X, broadcast modes are specified for side-chain communications only at the Physical (PHY) layer. Unicast and multicast modes need to be implemented at a higher level. For NR V2X side-chain communication, unicast and multicast communication are considered to be implemented directly at the PHY layer under standardization in release 16 of the 3 rd generation partnership project (3 GPP).

To enable hybrid automatic repeat request (HARQ) at the PHY layer, acknowledgement or non-acknowledgement (ACK/NACK) needs to be fed back from the receiver to the transmitter. There is a need to configure related feedback resources and to multiplex feedback from multiple User Equipments (UEs) to improve feedback efficiency.

Disclosure of Invention

In general, example embodiments of the present disclosure provide devices, methods, apparatuses, and computer-readable storage media for resource configuration of a feedback channel for device-to-device communication.

In a first aspect, a first terminal device is provided, the first terminal device comprising at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the first terminal device to select a subchannel from a plurality of subchannels of the device-to-device data channel during a transmission time period in response to device-to-device data to be transmitted to the second terminal device over the device-to-device data channel during the transmission time period. The first terminal device is further caused to select a feedback period from a plurality of feedback periods on the device-to-device feedback channel based on the transmission period and a predetermined delay range between the device-to-device data channel and the device-to-device feedback channel. The first terminal device is further caused to send an indication of the feedback period to the second terminal device to enable the second terminal device to send an acknowledgement of the device-to-device data over the device-to-device feedback channel within the feedback period.

In a second aspect, a second terminal device is provided, the second terminal device comprising at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the second terminal device to decode device-to-device data from the first terminal device at a subchannel of a plurality of subchannels of the device-to-device data channel over a transmission time period. The second terminal device is caused to receive an indication of a feedback period of the plurality of feedback periods from the first terminal device on a device-to-device feedback channel. The second terminal device is further caused to determine a code sequence from the plurality of orthogonal code sequences based on a predetermined association between the plurality of subchannels and the plurality of orthogonal code sequences of the feedback period. The second terminal device is also caused to send an acknowledgement of the device-to-device data to the first terminal device using the selected code sequence over the device-to-device feedback channel for a feedback period of time.

In a third aspect, a network device is provided that includes at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the network device to allocate a plurality of feedback time periods in the resource pool to the device-to-device feedback channel. The network device is caused to allocate a plurality of orthogonal code sequences for a feedback period of a plurality of feedback periods. The network device is also caused to determine a delay range between the device-to-device data channel and the device-to-device feedback channel. The network device is also caused to associate a plurality of orthogonal code sequences with at least a plurality of sub-channels of the device-to-device data channel within a transmission time period based on the delay range.

In a fourth aspect, a method is provided. In the method, the first terminal device selects a subchannel from a plurality of subchannels of the device-to-device data channel during a transmission time period in response to device-to-device data to be transmitted to the second terminal device during the transmission time period on the device-to-device data channel. The first terminal device selects a feedback period from a plurality of feedback periods on the device-to-device feedback channel based on the transmission period and a predetermined delay range between the device-to-device data channel and the device-to-device feedback channel. The first terminal device also sends an indication of the feedback period to the second terminal device to enable the second terminal device to send an acknowledgement of the device-to-device data over the device-to-device feedback channel for the feedback period.

In a fifth aspect, a method is provided. In the method, the second terminal device decodes device-to-device data from the first terminal device at a subchannel of a plurality of subchannels of the device-to-device data channel during a transmission time period. The second terminal device receives an indication of a feedback period of the plurality of feedback periods from the first terminal device on a device-to-device feedback channel. The second terminal device determines a code sequence from among the plurality of orthogonal code sequences based on a predetermined association between the plurality of subchannels and the plurality of orthogonal code sequences of the feedback period. The second terminal device transmits an acknowledgement of the device-to-device data to the first terminal device using the selected code sequence over the device-to-device feedback channel for a feedback period of time.

In a sixth aspect, a method is provided. In the method, a network device allocates a plurality of feedback time periods to a device-to-device feedback channel in a resource pool. The network device allocates a plurality of orthogonal code sequences for a feedback period of the plurality of feedback periods. The network device determines a delay range between the device-to-device data channel and the device-to-device feedback channel. The network device associates a plurality of orthogonal code sequences with at least a plurality of subchannels of the device-to-device data channel during the transmission time period based on the delay range.

In a seventh aspect, there is provided an apparatus comprising means for performing the method according to the fourth, fifth or sixth aspect.

In an eighth aspect, a computer readable storage medium having a computer program stored thereon is provided. The computer program, when executed by a processor of a device, causes the device to perform the method according to the fourth, fifth or sixth aspect.

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

Drawings

Some example embodiments will now be described with reference to the accompanying drawings, in which:

FIG. 1 illustrates an example resource configuration of a short PSFCH in a resource pool;

FIG. 2 illustrates an example environment in which embodiments of the present disclosure may be implemented;

FIG. 3 illustrates an example structure of a resource pool according to some example embodiments of the present disclosure;

FIG. 4 illustrates an example extended resource configuration in a resource pool according to some example embodiments of the present disclosure;

fig. 5 illustrates signaling flows between a network device and two terminal devices according to some example embodiments of the present disclosure;

fig. 6 illustrates an example resource configuration in a resource pool for D2D communication according to some example embodiments of the present disclosure;

fig. 7 illustrates an example structure of a D2D feedback channel according to some example embodiments of the present disclosure;

FIG. 8 illustrates an example configuration of delay ranges according to some example embodiments of the present disclosure;

Fig. 9 illustrates an example association between a D2D data channel and a D2D feedback channel according to some example embodiments of the present disclosure;

fig. 10 illustrates an example selection of D2D resources according to some example embodiments of the present disclosure;

fig. 11 illustrates signaling flows between a network device and two terminal devices according to some other example embodiments of the present disclosure;

FIG. 12 illustrates an example configuration of delay ranges according to some other example embodiments of the present disclosure;

fig. 13 illustrates an example association between a D2D data channel and a D2D feedback channel according to some example embodiments of the present disclosure;

Fig. 14 illustrates an example selection of feedback time periods for a D2D feedback channel according to some example embodiments of the present disclosure;

FIG. 15 illustrates a flowchart of an example method according to some example embodiments of the present disclosure;

FIG. 16 illustrates a flowchart of an example method according to some other example embodiments of the present disclosure;

FIG. 17 shows a flowchart of an example method in accordance with other example embodiments of the present disclosure, and

Fig. 18 shows a simplified block diagram of a device suitable for implementing embodiments of the present disclosure.

The same or similar reference numbers will be used throughout the drawings to refer to the same or like elements.

Detailed Description

Principles of the present disclosure will now be described with reference to some example embodiments. It should be understood that these embodiments are described merely for the purpose of illustrating and helping those skilled in the art to understand and practice the present invention and are not meant to limit the scope of the present disclosure in any way. The disclosure described herein may be implemented in various ways other than those described below.

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

As used herein, the term "network device" refers to a device via which services can be provided to terminal devices in a communication network. Examples of network devices may include relays, access Points (APs), transmission points (TRPs), node bs (nodebs or NB), evolved nodebs (eNodeB or eNB), new Radio (NR) nodebs (gNB), remote radio modules (RRU), radio Headers (RH), remote Radio Heads (RRHs), low power nodes (such as femto, pico), etc.

As used herein, the term "terminal device" or "user equipment" (UE) refers to any terminal device capable of wireless communication with each other or with a base station. Communication may involve the transmission and/or reception of wireless signals using electromagnetic signals, radio waves, infrared signals, and/or other types of signals suitable for conveying information over the air. In some example embodiments, the UE may be configured to transmit and/or receive information without direct human-machine interaction. For example, the UE may transmit information to the network device according to a predetermined schedule when triggered by an internal or external event, or in response to a request from the network side.

Examples of UEs include, but are not limited to, user Equipment (UE), such as smart phones, wireless enabled tablet computers, laptop embedded devices (LEEs), laptop mounted devices (LMEs), wireless Customer Premise Equipment (CPE), sensors, metering devices, personal wearable devices such as watches, and/or vehicles capable of communication. The terminal device may also include a vehicle that communicates V2X via a D2D side chain. For purposes of discussion, some example embodiments will be described with reference to a UE as an example of a terminal device, and the terms "terminal device" and "user equipment" (UE) may be used interchangeably in the context of this disclosure.

As used herein, the term "circuitry" may refer to one or more or all of the following:

(a) Pure hardware circuit implementations (such as implementations in analog and/or digital circuitry only), and

(B) A combination of hardware circuitry and software, such as (i) a combination of analog and/or digital hardware circuit(s) and software/firmware, as applicable, and (ii) any portion of a hardware processor having software, including digital signal processor(s), and memory(s), that cooperate to cause a device, such as a mobile phone or server, to perform various functions, and

(C) Hardware circuit(s) and/or processor(s), such as microprocessor(s) or portion of microprocessor(s), that require software (e.g., firmware) to operate, but may not require software to operate.

The definition of circuitry applies to all uses of this term in this application, including in any claims. As another example, as used in this disclosure, the term circuitry also encompasses hardware-only circuitry or processor (or multiple processors) or an implementation of a hardware circuit or portion of a processor and its (or their) accompanying software and/or firmware. For example, if applicable to the particular claim element, the term circuitry also encompasses a baseband integrated circuit or processor integrated circuit for a mobile device, or a similar integrated circuit in a server, a cellular network device, or other computing or network device.

As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term "comprising" and variants thereof should be understood to mean open-ended terms including, but not limited to. The term "based on" should be understood as "based at least in part on". The terms "one embodiment" and "an embodiment" should be understood as "at least one embodiment". The term "another embodiment" should be understood as "at least one other embodiment". Other definitions (explicit and implicit) may be included below.

As used herein, the terms "first," "second," and the like may be used herein to describe various elements, which should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term "and/or" includes any and all combinations of one or more of the listed terms.

Unlike LTE V2X, both unicast and multicast communications need to be implemented directly at the PHY layer to improve the transmission efficiency of these communications. There is a need to design more advanced schemes to enable direct communication at the PHY layer. For example, a short physical side chain feedback channel (PSFCH) is assigned for acknowledgement feedback in side chain communication.

Fig. 1 illustrates an example resource configuration of a short PSFCH in a resource pool 100. As shown, in every N time slots 105-1, 105-N, where N represents a positive integer, one time slot 105-N is configured for a short PSFCH 110, short PSFCH 110 occupies the last three (or more) symbols in slot 105-N (14 symbols total per slot) for a period of N slots. The short PSFCH 110 occupies the entire frequency band 115 in the resource pool 100. Typically, the first symbol of short PSFCH is used for Automatic Gain Control (AGC) and the last symbol is used for transmit and receive (T/R) switching. Only the middle symbol(s) are actually used to convey HARQ feedback.

The inventors noted that the scheme using the short PSFCH has the following drawbacks. First, the feasibility of this scheme is constrained by half-duplex. For example, when there is bi-directional unicast communication between two UEs, both UEs may need to feedback ACK/NACK in the same PSFCH slots to meet the respective delay requirements. However, due to half duplex constraints, this is not feasible because the UE cannot transmit and receive simultaneously. Furthermore, stringent delay requirements may not be met because the UE must wait PSFCH slots to feed back the ACK/NACK.

The inventors have also noted that one approach for alleviating the above two problems may be to reduce the period of the N slots. However, the small period of short PSFCH may result in a significant resource consumption because short PSFCH occupies the entire frequency band of the configured resource pool, as shown in fig. 1.

Embodiments of the present disclosure provide a feasible and efficient resource configuration scheme for feedback channels (e.g., hybrid configurations of HARQ feedback channels such as PSFCH) in device-to-device (D2D) communications (e.g., side-chain communications). According to this scheme, the feedback channel is configured to have a plurality of feedback time periods (such as slots or subframes) in the time domain. The feedback period may be continuous. The feedback channel may occupy one or more PRBs of the network configuration in the frequency domain. When the terminal device intends to initiate a D2D transmission, the terminal device selects one of a plurality of feedback periods for receiving an acknowledgement from the recipient. The determination is based on a predetermined delay range between the D2D data channel and the D2D feedback channel, such as a physical side chain shared channel (PSSCH). The delay range may be dynamically configured, or pre-configured semi-statically or statically by the network, or predefined in the 3GPP specifications. The terminal device indicates the selected feedback period to the receiver to enable the receiver to feedback the ACK/NACK.

Further, the association between the plurality of orthogonal code sequences and the D2D data channel is configured, preconfigured or predefined. The orthogonal code sequences may be generated by base sequences (such as Zadoff-Chu sequences) with different Code Division Multiplexing (CDM) signatures. The CDM signature may be a combination of cyclic shift and Orthogonal Cover Code (OCC). For example, each subchannel of a D2D data channel in one or more transmission periods (e.g., time slots) is configured with a unique CDM signature for HARQ feedback in the corresponding feedback channel. Such resource allocation of the feedback channel may provide timely HARQ feedback for traffic with stringent delay requirements and may effectively alleviate half-duplex constraints.

FIG. 2 illustrates an example environment 200 in which embodiments of the present disclosure may be implemented. The environment 200, which is part of a communication network, comprises two terminal devices 210 and 220 (referred to as a first terminal device 210 and a second terminal device 220, respectively) and a network device 230. It should be understood that two terminal devices and one network device are shown in fig. 2 for illustrative purposes only and not to imply any limitation.

The two terminal devices 210 and 220 may communicate directly via a D2D connection or via the network device 230. The two terminal devices 210 and 220 may also communicate with other terminal devices (not shown) directly or via the network device 230. Communications in environment 200 may conform to any suitable communication standard or protocol, such as Universal Mobile Telecommunications System (UMTS), long Term Evolution (LTE), LTE-advanced (LTE-a), fifth generation (5G) NR, wireless fidelity (Wi-Fi), and Worldwide Interoperability for Microwave Access (WiMAX) standards, and employ any suitable communication technology including, for example, multiple Input Multiple Output (MIMO), orthogonal Frequency Division Multiplexing (OFDM), time Division Multiplexing (TDM), frequency Division Multiplexing (FDM), code Division Multiplexing (CDM), bluetooth, zigBee, machine Type Communications (MTC), enhanced mobile broadband (eMBB), mass machine type communications (mMTC), ultra-reliable low delay communications (URLLC), carrier Aggregation (CA), dual Connectivity (DC), new radio unlicensed (NR-U), and V2X technologies.

For D2D communication between the two terminal devices 210 and 220, the network device 230 configures a resource pool. In the resource pool, the network device 230 configures resources of a D2D feedback channel for HARQ feedback in addition to the D2D data channel.

Fig. 3 illustrates an example structure of a resource pool 300 according to some example embodiments of the present disclosure.

The resource pool 300 includes a plurality of time periods 305-1, 305-2, and..the time period 305-N (collectively referred to as time period 305) in the time domain, where N represents any suitable positive integer. The time period 305 may have any suitable length of time. For example, the time period 305 may include a time slot in an NR network or a time subframe in an LTE network. Further, the resource pool 300 includes a plurality of subchannels 310-1 in the frequency domain, the term "subchannels 310", 310-M (collectively referred to as subchannels 310), where M represents any suitable positive integer. The sub-channel 310 may include one or more PRBs depending on the system configuration.

In the resource pool 300, the D2D data channel 315 is configured to have a plurality of time periods 305 in the time domain and a plurality of subchannels 310 in the frequency domain. The D2D data channel 315 may be implemented by the PSSCH. The resources of the D2D data channel 315 may also be used for D2D control channels, such as a physical side chain control channel (PSCCH).

Further, the D2D feedback channel 320 is configured in the resource pool 300, and the D2D feedback channel 320 occupies a plurality of consecutive time periods in the time domain. For ease of discussion, the period of time in the D2D data channel 315 is referred to as a transmission period, and the period of time in the D2D feedback channel 320 is referred to as a feedback period. In this example, the D2D feedback channel 320 occupies 1 PRB (or multiple PRBs configured by the network device 230) in each time period 305 of the resource pool 300. The D2D feedback channel 320 may be implemented by PSFCH. The D2D feedback channel 320 may provide timely HARQ feedback for services with stringent delay requirements and may alleviate half-duplex constraints.

Further, as shown, the short D2D feedback channel 325 is also configured to have a duration that is less than one time period. As an example, the short D2D feedback channel 325 may be implemented by the short PSFCH 110 as shown in fig. 1. In some example embodiments, the continuous feedback period of the D2D feedback channel 320 may not include the period 330 in which the short D2D feedback channel 325 is configured because the receiver may use the short D2D feedback channel 325 for HARQ feedback during the period 330.

Alternatively, the D2D feedback channel 320 is configured in the resource pool 300, and the D2D feedback channel 320 may not occupy a plurality of consecutive time periods in the time domain. As one example, as shown in fig. 3, time period 305-3 may be excluded from D2D feedback channel 320. The first terminal device will not select a period 305-3 for acknowledgement feedback. As another example, as shown in fig. 3, the D2D feedback channel 320 may occupy one time period every K (e.g., k=2) time periods. K may be set to a positive integer less than N, which means that the period of the D2D feedback channel 320 is shorter than the period of the short PSFCH.

With the resource configuration in the resource pool 300, when the first terminal device 210 performs D2D transmission to the second terminal device 220 on the D2D data channel 315, the second terminal device 220 may use the D2D feedback channel 320 for acknowledgement feedback for the D2D transmission.

The network device 230 also configures a delay range 335 between the D2D data channel 315 and the D2D feedback channel 320. In this example, as shown in FIG. 3, the delay range 335 is configured as [1,2]. That is, for D2D transmissions within time period t ₁ (e.g., time period 305-1) of D2D data channel 315, time periods Δ+1 and t ₁ +2 (e.g., time periods 305-2 and 305-3) of D2D feedback channel 320 may be used for feedback. Accordingly, time period t ₂ (e.g., time period 305-3) of D2D feedback channel 320 may be used to feedback data transmissions over D2D data channel 315 for time periods t ₂ -1 and t ₂ -2 (represented by time periods 305-1 and 305-2, respectively).

Different receiving terminal devices may use different orthogonal code sequences for ACK/NACK feedback during one time period. In some example embodiments, the same Zadoff-Chu sequence may be used to generate orthogonal code sequences using the same base sequence, such as Zadoff-Chu sequences with different CDM signatures. Different CDM signatures may be implemented by different combinations of cyclic shifts and Orthogonal Cover Codes (OCCs).

Further, the network device 230 configures an association between an orthogonal code sequence (e.g., CDM signature) of the D2D feedback channel 320 and the D2D data channel 315 within the delay range 335. For example, within the delay range 335, each subchannel 310 of the D2D data channel 315 is provided with a unique CDM signature for HARQ feedback on the D2D feedback channel 320. The CDM signature on D2D data channel 315 associated with time period t ₂ - Δt for use on D2D feedback channel 320 for time period t ₂ may be determined by (Δt, l), where l represents the index of the subchannel for time period t ₂ - Δt.

If the first terminal device 210 is to initiate a D2D data transmission to the second terminal device 220, the first terminal device 210 may select the sub-channel 310 on the D2D data channel 315 for a transmission period t ₁. Based on the delay range 335 and the association between the D2D data channel 315 and the D2D feedback channel 320 (pre) configured by the network device 230, the first terminal device 210 may select a feedback period t ₁ +Δt on the D2D feedback channel 320 for ACK/NACK feedback from the second terminal device 220.

The first terminal device 210 transmits an indication of the feedback period of the selected D2D feedback channel 320 to the second terminal device 220. The indication may be sent in side chain control information (SCI) on a D2D control channel, such as PSCCH, associated with D2D data channel 315. Thus, based on the indication, the second terminal device 220 may identify a feedback period of the D2D feedback channel 320 and determine a code sequence (such as a CDM signature) for ACK/NACK feedback. Alternatively, the indication may be sent in the D2D data channel 315. For example, the indication may be sent in the D2D data channel 315 with the data to further reduce signaling overhead.

Due to the limitation of the number of orthogonal code sequences (such as CDM signatures), in some example embodiments, a spreading scheme of the resource configuration of the D2D feedback channel 320 may be employed to reduce the number of different CDM signatures required on the D2D feedback channel. By extension, the delay range 335 may be divided into a plurality of delay sub-ranges represented by n sub-ranges, where n represents a positive integer. The association between the orthogonal code sequences and the D2D data channel 315 is reused in n sub-ranges.

Fig. 4 illustrates an example extended resource configuration in a resource pool 300 according to some example embodiments of the present disclosure.

In this example, the delay range 335 between the D2D data channel 315 and the D2D feedback channel 320 is configured as [1,4]. The delay range 335 is divided into two sub-ranges [1,2] and [3,4], denoted as sub-range 405 and sub-range 410, respectively. Within either sub-range 405 or 410, each sub-channel 310 of D2D data channel 315 is provided with a unique CDM signature for HARQ feedback over feedback time period 305-5 on D2D feedback channel 320.

Reuse of CDM signatures in n sub-ranges may significantly reduce the number of CDM signatures required for D2D feedback channel 320. Accordingly, the feedback period of the D2D feedback channel 320 may be used for ACK/NACK feedback of data transmitted on the plurality of sub-channels of the D2D data channel 315, and thus the resource consumption of the D2D feedback channel 320 may be reduced.

With reuse of CDM signatures, as shown in fig. 4, subchannels 310 of time periods 305-1 and 305-3 may be mapped to the same time period 305-5 of D2D feedback channel 320 and use the same CDM signature. In order to further improve feedback efficiency, upon selecting a feedback period in which ACK/NACK is fed back to data transmission, the first terminal device 210 may select a feedback period having an unused CDM signature based on detection or decoding of D2D control information on the D2D data channel 315 in the previous period 305.

Fig. 5 illustrates a signaling flow 500 between a network device 230 and two terminal devices 210 and 220 according to some example embodiments of the present disclosure. In this example, the network device 230 is implemented by the gNB and the two terminal devices 210 and 220 are implemented by the UE. The network device 230 communicates with the first terminal device 210 and the second terminal device 220 via a Uu interface, and the two terminal devices 210 and 220 may communicate over a D2D link.

As shown in fig. 5, the network device 230 determines 505 time and frequency resources of a short D2D feedback channel 325, such as the short PSFCH 110 shown in fig. 1. The configuration of the short D2D feedback channel 325 is optional. In some example embodiments, such a short feedback channel may not be configured. The network device 230 determines 510 time and frequency resources of the long D2D feedback channel 320.

The resource determination will be described below with reference to fig. 6, fig. 6 illustrates an example resource configuration in a resource pool 300 for D2D communication according to some example embodiments of the present disclosure.

As shown in fig. 6, in the time domain of the resource pool 300, the time resources of the short D2D feedback channel 325 occupy the last symbol in a period 305-N (e.g., a slot or subframe) with N periods. In the frequency domain, the frequency resources occupy the entire frequency band 605 of the sub-channel 310 in the resource pool 300.

For the long D2D feedback channel 320, the frequency resources in the frequency domain occupy 1 PRB (or multiple PRBs configured by the network device 230) for each time period of the resource pool 300. In the mixed resource configuration of the short D2D feedback channel 325 and the long D2D feedback channel 320, the period 330 configured with the short D2D feedback channel 325 may be excluded from the D2D feedback channel 320 because the receiver may use the short D2D feedback channel 325 when timely HARQ feedback is needed.

The D2D feedback channel 320 may occupy the entire period of each period in the time domain. Fig. 7 illustrates an example structure of a D2D feedback channel 320 according to some example embodiments of the present disclosure. In this example, as shown in fig. 7, the D2D feedback channel 320 occupies 12 subcarriers in the frequency domain. Further, in the time domain, the D2D feedback channel 320 occupies all symbols (e.g., 14 OFDM symbols) in the slot 705. Of the 14 symbols, the first symbol 710 is used for AGC and the last symbol 715 is used as a guard symbol (or GP). The middle 12 symbols 720 are used to carry ACK/NACK information.

In the slot 705, an orthogonal code sequence is allocated to the D2D feedback channel 320. For example, BPSK modulation is used, and the modulation symbols are spread with Zadoff-Chu sequences (denoted by r _u,v, with different cyclic shifts (denoted by α)) and Orthogonal Cover Codes (OCC) (denoted by w (1) to w (6)).

In some example embodiments, in the resource pool 300, the same Zadoff-Chu sequence is used for the D2D feedback channel 320. In D2D feedback channel 320, different receiving terminal devices may employ the same sequence but different CDM signatures for ACK/NACK feedback. CDM signatures are a combination of cyclic shifts and OCCs. Thus, multiplexing between HARQ feedback from a plurality of terminal devices is achieved. Furthermore, different Zadoff-Chu sequences may be employed by multiple resource pools in one region or cell or in multiple regions or cells to randomize mutual interference.

Alternatively, in the resource pool 300, a non-orthogonal code sequence having low cross correlation may be used for the D2D feedback channel 320. For example, the non-orthogonal code sequences may be generated from different base sequences (such as Zadoff-Chu sequences with low cross-correlation).

Still referring to fig. 5, the network device 230 determines (515) a delay range of Δt between the D2D data channel 315 and the D2D feedback channel 320 for HARQ feedback [ a, b ]. The delay Δt between the time period t ₁ on the D2D data channel 315 and the time period t ₂ on the D2D feedback channel 320 is t ₂-t₁. The delay range may be set based on factors such as the number of subchannels in the resource pool 300, the number of PRBs of the short D2D feedback channel 325, the period N, D of the 2D feedback channel 320, and the like. Some example values of the delay range may include [2,4], [2,2], [1,3], [1,1].

The network device 230 associates 520 a plurality of orthogonal code sequences with a plurality of subchannels 310 of a D2D data channel 315 within a delay range 335. In some example embodiments, the same Zadoff-Chu sequence is used for the resource pool 300. Different CDM signatures are associated with subchannels 310 within delay range 335. In this way, each sub-channel 310 within the delay range is provided with a unique CDM signature for HARQ feedback for a corresponding feedback period on the D2D feedback channel 320.

The CDM signature of time period t ₂ on D2D feedback channel 320 associated with subchannel l over time period t ₁ on D2D data channel 315 is determined by (Δt, l), where Δt = t ₂-t₁, l represents the index of subchannel 310 of D2D data channel 315. If the D2D data channel 315 occupies multiple (more than one) subchannels 310, l may represent an index of a starting subchannel of the D2D data channel 315.

Fig. 8 illustrates an example configuration of a delay range 335 according to some example embodiments of the present disclosure. In this example, the delay range 335 is configured as [1,2]. Subchannels 310 in time periods 305-1 and 305-2 (represented by t ₂ -2 and t ₂ -1) have different CDM signatures for their respective HARQ feedback over D2D feedback channel 320 for a corresponding time period 305-3 (represented by time period t ₂).

Fig. 9 illustrates an example association between a D2D data channel 315 and a D2D feedback channel 320 according to some example embodiments of the present disclosure. In this example, while one terminal device (e.g., first terminal device 210) transmits D2D data in time period 305-1 (represented by time period t ₂ -2) and subchannel 310 (represented by subchannel l), the other terminal device (e.g., second terminal device 220) transmits D2D data in time period 305-2 (represented by time period t ₂ -1) and subchannel 310 (represented by subchannel l). Its corresponding receiving terminal device may feedback ACK/NACK over the D2D feedback channel 320 for feedback period 305-3 (represented by period t ₂), but with a different CDM signature to multiplex.

Still referring to fig. 5, the network device 230 sends (525) an indication of the resource configuration of the D2D feedback channel 320 to both the first terminal device 210 and the second terminal device 220. As an example, the indication may be sent in a broadcast or multicast message such as a System Information Block (SIB) or a Master Information Block (MIB). As an alternative example, the indication may be sent in a dedicated message such as Radio Resource Control (RRC) signaling.

The network device 230 sends (530) an indication of the delay range and the resource association to both the first terminal device 210 and the second terminal device 220. The indication may also be sent in a broadcast message such as SIB or MIB, or in a dedicated message such as RRC signaling. The delay range and/or resource association may be dynamically, semi-statically, or statically configured by the network device 230. Alternatively, the configuration may be predefined in the relevant 3GPP specifications.

It should be appreciated that the delay range may be configured or predefined as some single value, such as [2,2]. In this case, the first terminal device 210 does not need to indicate the feedback period to the second terminal device 220.

The first terminal device 210 and the second terminal device 220 may perform D2D communication through an association between the D2D data channel 315 and the D2D feedback channel 320 configured or predefined by the network device 230, and a delay range set by the network device 230. As shown, the first terminal device 210 selects (535) one or more sub-channels of the D2D data channel 315 for D2D communication with the second terminal device 220. For example, the selected subchannel may be represented by (t ₁, l), where t ₁ represents a time period and l represents an index of the subchannel in the frequency domain.

Based on the delay range, the first terminal device 210 selects (540) a time period t ₁ +Δt on the D2D feedback channel 320 for ACK/NACK feedback from the second terminal device 220. In addition to the delay range, the selection of the time period on the D2D feedback channel 320 may be accomplished by considering any other suitable factors such as delay requirements and half-duplex constraints.

Fig. 10 illustrates example selections of D2D resources according to some example embodiments of the disclosure. In this example, the delay range is configured as [1,2] as shown. The first terminal device 210 selects a subchannel 310 for the D2D transmission during the time period 305-1. In this case, there are two potential time periods 305-2 and 305-3 on the D2D feedback channel 320. The first terminal device 210 may select one of the two time periods 305-2 and 305-3 for feedback.

Still referring to fig. 5, the first terminal device 210 sends (545) an indication of the feedback period to the second terminal device 220 over a D2D control channel, such as a PSCCH. For example, the first terminal device 210 may include feedback delay information Δt as an indication in the SCI of the PSCCH associated with the PSSCH. The first terminal device 210 also transmits (550) data to the second terminal device 220 on the selected sub-channel 310 of the D2D data channel 315.

The second terminal device 220 decodes (555) the data on the sub-channel 310 of the D2D data channel 315. Based on a predetermined association between the subchannels of the D2D data channel 315 and the plurality of orthogonal code sequences, the second terminal device 220 determines (560) a code sequence from the plurality of orthogonal code sequences. For example, in an example embodiment in which the same base sequence (such as the same Zadoff-Chu sequence) the second terminal device 220 determines the CDM signature based on (Δt, l) and a (pre) configured/predefined association between the D2D data channel 315 and the D2D feedback channel 320. The second terminal device 220 transmits (565) an ACK/NACK over the D2D feedback channel 320 for a feedback period using the determined CDM signature.

Fig. 11 illustrates an example signaling flow 1100 between a network device 230 and two terminal devices 210 and 220 according to some other embodiments of the present disclosure. In this example, the extended association between the D2D data channel 315 and the D2D feedback channel 320 is configured to reduce the resource consumption of HARQ feedback.

As shown, the network device 230 determines (1105) the time and frequency resources of the short D2D feedback channel 325. The network device 230 determines 1110 time and frequency resources of the long D2D feedback channel 320. The network device 230 configures 1115 a delay range a, b of Δt between the D2D data channel 315 and the D2D feedback channel 320 for HARQ feedback. The determination of the resources and delay ranges for the short D2D feedback channel 325 and the long D2D feedback channel 320 is similar to the determination of the resources and delay ranges for the short D2D feedback channel 325 and the long D2D feedback channel 320 described above with reference to fig. 5. For simplicity, the description will not be repeated.

The network device 230 associates 1120 a plurality of orthogonal code sequences of the D2D feedback channel 320 with a plurality of subchannels of the D2D data channel 315. In this example, the delay range is divided into n sub-ranges of [ a, a+m-1], [ a+m, a+2m-1], [ a+ (n-1) m, a+nm-1], where b-a+1=nm. The association between the D2D data channel 315 and the D2D feedback channel 320 is repeated for n sub-ranges. For example, the same CDM signature used over time period t ₂ on D2D feedback channel 320 is associated with sub-channel (t ₂ - Δt, l) and sub-channel (t ₂ - Δt-km, l) on D2D data channel 315. Within the sub-range, a unique CDM signature is provided for HARQ feedback on the D2D feedback channel. The association may be pre-configured semi-statically or statically by the network device 230, or dynamically by the network device 230, or predefined in the network.

Repetition of the association may reduce the number of different CDM signatures required for D2D feedback channel 320. The larger the number of different CDM signatures required, the wider (more PRBs) the D2D feedback channel 320. Thus, extending the association may ultimately reduce the resource consumption of the D2D feedback channel 320.

Fig. 12 illustrates an example configuration of a delay range 335 according to some other example embodiments of the present disclosure. In this example, the delay range 335 is configured as [1,4]. The association between the D2D data channel 315 and the D2D feedback channel 320 is the same in the two sub-ranges 405 and 410 denoted as [1,2] and [3, 4].

Still referring to fig. 11, the network device 230 sends (1125) an indication of the resource configuration of the D2D feedback channel 320 to both the first terminal device 210 and the second terminal device 220. The network device 230 also sends (1130) an indication of the delay range and the resource association to both the first terminal device 210 and the second terminal device 220.

To avoid collisions caused by reuse of CDM signatures, enhanced sensing of control information on D2D data channel 315 is enabled at first terminal device 210. As shown in fig. 11, the first terminal device 210 decodes (1135) control information from other terminal devices on the D2D data channel 315. Based on the indication of the time period t ₂ to be used for feedback on the D2D feedback channel 320 (e.g., information about feedback delay Δt included in the control information on the D2D data channel 315), the first terminal device 210 identifies (1140) the time period t ₂ and CDM signature to be used for HARQ feedback on the D2D feedback channel 320.

The first terminal device 210 selects (1145) the subchannel denoted by (t ₁, l) for D2D transmission.

The first terminal device 210 selects 1150 a feedback period of the D2D feedback channel 320. In some example embodiments, based on the range/sub-range information, the delay requirement, and the half-duplex constraint, first terminal device 210 selects a time period t ₁ +Δt with an unused CDM signature. For example, if the time period t ₁ +Δt is not selected by other terminal devices for transmitting ACK/NACK corresponding to data transmitted within the time period t ₁ -km at subchannel l, the time period t ₁ +Δt may be selected by the first terminal device 210.

In an example embodiment in which CDM signatures are reused for n sub-ranges of the delay range, the feedback period may be selected from candidate feedback periods by detecting the feedback period of the D2D feedback channel 320 to be used by other terminal devices based on the delay range [ a, b ], the delay requirement, and the delay half-duplex constraint.

Fig. 13 illustrates an example association between a D2D data channel 315 and a D2D feedback channel 320 according to some example embodiments of the present disclosure. When another terminal device transmits D2D data to the second terminal device 220 at subchannel 310 (represented by time period t ₁, subchannel l) within time period 305-1 of D2D data channel 315, the first terminal device transmits D2D data at subchannel 310 (represented by time period t ₁ +2, subchannel l) within time period 305-3. If the first terminal device 210 determines that a period 305-5 (represented by period t ₁ +4) of the D2D feedback channel 320 has been selected by another terminal device for feedback, the first terminal device 210 selects a feedback period of the D2D feedback channel 320 with an unused CDM signature to avoid collision. The feedback period may be selected from candidate feedback periods by detecting a feedback period to be previously used by other terminal devices based on the delay range [ a, b ], the delay requirement, and the half-duplex constraint.

Fig. 14 illustrates an example selection of feedback time periods for a D2D feedback channel 320 according to some example embodiments of the present disclosure.

In this example, the delay range is configured as [1,4], [1,4] is divided into two sub-ranges of [1,2] and [3,4 ]. If the first terminal device 210 selects the subchannel 310 (represented by time period t ₁, subchannel l) for D2D transmission during time period 305-1, there are four potential resource blocks on the D2D feedback channel 320 during time periods 305-2 through 305-5 (represented by time periods t ₁+1、t₁+2、t₁ +3 and t ₁ + 4).

Still referring to fig. 11, the first terminal device 210 sends (1155) an indication of the resource blocks selected on the D2D feedback channel 320 to the second terminal device 220 via a D2D control channel, such as a PSCCH. The first terminal device 210 transmits (1160) the D2D data to the second terminal device 220. The second terminal device 220 decodes the D2D data (1165). Then, the second terminal device 220 determines a CDM signature for ACK/NACK feedback. The second terminal device 220 transmits (1175) an ACK/NACK in the feedback period using the determined CDM signature.

Fig. 15 illustrates a flowchart of an example method 1500 of resource configuration, according to some example embodiments of the present disclosure. The method 1500 may be implemented by the network device 230 shown in fig. 2. For discussion purposes, the method 1500 will be described with reference to FIG. 2.

At block 1505, the network device 230 allocates a plurality of feedback time periods to the D2D feedback channel in the resource pool. At block 1510, the network device 230 allocates a plurality of orthogonal code sequences for a feedback period of the plurality of feedback periods. At block 1515, the network device 230 determines a delay range between the D2D data channel and the D2D feedback channel. At block 1520, the network device 230 associates a plurality of orthogonal code sequences with at least a plurality of subchannels of the D2D data channel for a transmission period based on the delay range.

In some example embodiments, the network device 230 sends an indication of the delay range to at least the first terminal device 210.

In some example embodiments, the network device 230 associates a plurality of orthogonal code sequences with at least a plurality of subchannels during a transmission period and with a plurality of other subchannels during additional transmission periods. In some example embodiments, the delay range includes at least a first delay sub-range and a second delay sub-range. The time difference between the transmission period and the feedback period is within a first delay sub-range and the time difference between the further transmission period and the feedback period is within a second delay sub-range.

In some example embodiments, the network device 230 sends an indication of the association between the plurality of orthogonal code sequences and the plurality of subchannels to at least the first terminal device 210 and the different second terminal device 220.

In some example embodiments, the network device 230 allocates a frequency band for the device-to-device feedback channel in the resource pool. In some example embodiments, the allocated frequency band includes one or more physical resource blocks. Alternatively, the network device 230 may allocate different physical resource blocks in a plurality of time periods to the device-to-device feedback channel.

In some example embodiments, the time period includes a time slot. In some example embodiments, the D2D data channel comprises a physical side chain shared channel and the D2D feedback channel comprises a physical side chain feedback channel.

Fig. 16 illustrates a flowchart of an example method 1600, according to some example embodiments of the present disclosure. The method 1600 may be implemented by the first terminal device 210 shown in fig. 2. For discussion purposes, method 1600 will be described with reference to FIG. 2.

In block 1605, in response to the D2D data to be transmitted to the second terminal device 220 over the D2D data channel during the transmission period, the first terminal device 210 selects a subchannel from a plurality of subchannels of the D2D data channel during the transmission period. At block 1610, the first terminal device 210 selects a feedback period from a plurality of feedback periods on the D2D feedback channel based on the transmission period and a predetermined delay range between the D2D data channel and the D2D feedback channel. At block 1615, the first terminal device 210 sends an indication of the feedback period to the second terminal device 220 to enable the second terminal device 220 to send an acknowledgement of the D2D data over the D2D feedback channel for the feedback period.

In some example embodiments, the first terminal device 210 determines a code sequence associated with the selected subchannel from among the plurality of orthogonal code sequences based on a predetermined association between the plurality of orthogonal code sequences and at least the plurality of subchannels of the feedback period. The first terminal device 210 determines whether the code sequence is to be used for acknowledging the further D2D data. If it is determined that the code sequence is to be used to acknowledge the further D2D data, the first terminal device 210 selects a further sub-channel from the plurality of sub-channels for transmitting the D2D data to the second terminal device within the transmission period.

In some example embodiments, the first terminal device 210 detects an indication from the third terminal device that the indication feedback period is to be used to confirm the further D2D data. Upon detecting the indication, the first terminal device 210 determines whether the code sequence is to be used for acknowledging further D2D data.

In some example embodiments, a plurality of orthogonal code sequences are associated with at least a plurality of subchannels during a transmission period and with a plurality of other subchannels during a further transmission period.

In some example embodiments, the delay range includes at least a first delay sub-range and a second delay sub-range. The time difference between the transmission period and the feedback period is within a first delay sub-range and the time difference between the further transmission period and the feedback period is within a second delay sub-range.

In some example embodiments, the first terminal device 210 receives an indication of the predetermined association from the network device 230.

In some example embodiments, the first terminal device 210 selects, within a further transmission period, a further sub-channel from a plurality of other sub-channels for transmission of the device-to-device data on the device-to-device data channel. Then, the first terminal device 210 selects a feedback period from the plurality of feedback periods based on the additional transmission period and the predetermined delay range. Based on a predetermined association between the plurality of orthogonal code sequences and the plurality of other subchannels of the selected feedback period, the first terminal device 210 determines a code sequence associated with the further subchannel from the plurality of orthogonal code sequences. Further, the first terminal device 210 determines whether the code sequence is to be used for acknowledging further device-to-device data. If it is determined that the code sequence is to be used to acknowledge additional device-to-device data, the first terminal device 210 determines that the device-to-device data is to be transmitted within the transmission period. Further, the first terminal device 210 selects a subchannel from among a plurality of subchannels for transmitting device-to-device data to the second terminal device within a transmission period.

In some example embodiments, the first terminal device 210 selects a candidate feedback period set from a plurality of feedback periods based on the transmission period and the predetermined delay range. The time difference between each candidate feedback period and the transmission period is within a predetermined delay range. The first terminal device 210 selects a feedback period from the set of candidate feedback periods.

In some example embodiments, the first terminal device 210 receives an indication of the time and frequency resources of the D2D feedback channel from the network device 230. The first terminal device 210 determines a plurality of feedback time periods in time and frequency resources.

In some example embodiments, the first terminal device 210 receives an indication of the predetermined delay range from the network device 230.

In some example embodiments, the time period includes a time slot. In some example embodiments, the D2D data channel comprises a physical side chain shared channel and the D2D feedback channel comprises a physical side chain feedback channel. In some example embodiments, the first terminal device 210 sends an indication of the feedback period to the second terminal device 220 on a physical side chain control channel.

Fig. 17 illustrates a flowchart of an example method 1700 according to some other example embodiments of the present disclosure. The method 1700 may be implemented by the second terminal device 220 shown in fig. 2. For discussion purposes, the method 1700 will be described with reference to fig. 2.

At block 1705, the second terminal device 220 decodes the D2D data from the first terminal device 210 at a subchannel of the plurality of subchannels of the D2D data channel during the transmission time period. At block 1710, the second terminal device 220 receives an indication of a feedback period of the plurality of feedback periods from the first terminal device 210 over the D2D feedback channel. At block 1715, the second terminal device 220 determines a code sequence from the plurality of orthogonal code sequences based on a predetermined association between the plurality of subchannels and the plurality of orthogonal code sequences of the feedback period. At block 1720, the second terminal device 220 transmits an acknowledgement of the D2D data to the first terminal device 210 over the D2D feedback channel using the selected code sequence for a feedback period.

In some example embodiments, the second terminal device 220 receives an indication of the predetermined association from the network device 230.

In some example embodiments, the second terminal device 220 receives an indication of the time and frequency resources of the D2D feedback channel from the network device 230. The second terminal device 220 determines a plurality of feedback time periods in the time and frequency resources.

In some example embodiments, the time period includes a time slot. In some example embodiments, the D2D data channel comprises a physical side chain shared channel and the D2D feedback channel comprises a physical side chain feedback channel. In some example embodiments, the second terminal device 220 receives an indication of the feedback period from the first terminal device on a physical side chain control channel.

All of the operations and features described above with reference to fig. 2-14 are equally applicable to, and have similar effects as, methods 1500-1700. Details will be omitted for simplicity.

Fig. 18 is a simplified block diagram of a device 1800 suitable for practicing embodiments of the present disclosure. The device 1800 may be implemented at the network device 230 or the first terminal device 210 or the second terminal device 220 as shown in fig. 2.

As shown, the device 1800 includes a processor 1810, a memory 1820 coupled to the processor 1810, a communication module 1830 coupled to the processor 1810, and a communication interface (not shown) coupled to the communication module 1830. Memory 1820 stores at least programs 1840. The communication module 1830 is used for bi-directional communication, e.g., via multiple antennas. The communication interface may represent any interface required for communication.

The program 1840 is assumed to include program instructions that, when executed by the associated processor 1810, enable the device 1800 to operate in accordance with embodiments of the present disclosure, as discussed herein with reference to fig. 2-17. The embodiments herein may be implemented by computer software executable by the processor 1810 of the device 1800, or by hardware, or by a combination of software and hardware. The processor 1810 may be configured to implement various embodiments of the present disclosure.

Memory 1820 may be of any type suitable to the local technical network and may be implemented using any suitable data storage technology, such as non-transitory computer readable storage media, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory, as non-limiting examples. Although only one memory 1820 is shown in device 1800, there may be several physically distinct memory modules in device 1800. The processor 1810 may be of any type suitable to a local technology network and may include, by way of non-limiting example, one or more of general purpose computers, special purpose computers, microprocessors, digital Signal Processors (DSPs), and processors based on a multi-core processor architecture. The device 1800 may have multiple processors, such as an application specific integrated circuit chip that is subordinate in time to a clock synchronized with the host processor.

When the device 1800 is used as a network device 230 or as part of a network device 230, the processor 1810 and the communication module 1830 may cooperate to implement the method 1500 as described above with reference to fig. 15. When the device 1800 is used as the first terminal device 210 or as part of the first terminal device 210, the processor 1810 and the communication module 1830 may cooperate to implement the method 1600 as described above with reference to fig. 16. When the device 1800 is used as the second terminal device 220 or as part of the second terminal device 220, the processor 1810 and the communication module 1830 may cooperate to implement the method 1700 as described above with reference to fig. 17. All of the operations and features described above with reference to fig. 2-17 are equally applicable to the device 1800 and have similar effects. Details will be omitted for simplicity.

In general, the various embodiments of the disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of the embodiments of the disclosure are illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that the blocks, apparatus, systems, techniques or methods described herein may be implemented in hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, that are executed in a device on a target real or virtual processor to perform the processes 500 and 1100 and methods 1500-1700 described above with reference to fig. 2-17. Generally, program modules include routines, programs, libraries, objects, classes, components, data types, etc. that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within local or distributed devices. In distributed devices, program modules may be located in both local and remote memory storage media.

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

In the context of this disclosure, computer program code or related data may be carried by any suitable carrier to enable an apparatus, device, or processor to perform the various processes and operations described above. Examples of carriers include signals, computer readable media, and the like.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. The computer readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus or devices, or any suitable combination thereof. More specific examples of a computer-readable storage medium include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), a Digital Versatile Disc (DVD), an optical storage device, a magnetic storage device, or any suitable combination thereof.

Moreover, although operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In some cases, multitasking and parallel processing may be advantageous. Also, while the above discussion contains several specific implementation details, these should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features specific to particular embodiments. Certain features that are described in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination.

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

Various embodiments of the technology have been described. In addition to or instead of the above, the following examples are described. The features described in any of the examples below may be used with any of the other examples described herein.

In some aspects, a first terminal device includes at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the first terminal device to select a subchannel from a plurality of subchannels of a device-to-device data channel over a transmission period in response to device-to-device data to be transmitted to a second terminal device over the device-to-device data channel over the transmission period, select a feedback period from a plurality of feedback periods over a device-to-device feedback channel based on the transmission period and a predetermined delay range between the device-to-device data channel and the device-to-device feedback channel, and send an indication of the feedback period to the second terminal device to enable the second terminal device to transmit an acknowledgement of the device-to-device data over the device-to-device feedback channel over the feedback period.

In some example embodiments, the first terminal device is further caused to determine a code sequence associated with the selected subchannel from among a plurality of orthogonal code sequences of the feedback period based on a predetermined association between the plurality of orthogonal code sequences and at least the plurality of subchannels, determine whether the code sequence is to be used to acknowledge additional device-to-device data, and select an additional subchannel from the plurality of subchannels for transmitting the device-to-device data to the second terminal device within the transmission period in response to determining that the code sequence is to be used to acknowledge the additional device-to-device data.

In some example embodiments, the first terminal device is caused to determine whether the code sequence is to be used to confirm the further device-to-device data by detecting an indication from a third terminal device indicating that the feedback period is to be used to confirm the further device-to-device data, and in response to detecting the indication, determining whether the code sequence is to be used to confirm the further device-to-device data.

In some example embodiments, the plurality of orthogonal code sequences are associated with at least the plurality of subchannels during the transmission period and with a plurality of other subchannels during a further transmission period.

In some example embodiments, the delay range includes at least a first delay sub-range and a second delay sub-range, and the time difference between the transmission period and the feedback period is within the first delay sub-range and the time difference between the further transmission period and the feedback period is within the second delay sub-range.

In some example embodiments, the first terminal device is further caused to receive an indication of the predetermined association from a network device.

In some example embodiments, the first terminal device is caused to select the subchannel from the plurality of subchannels by selecting a further subchannel from a plurality of other subchannels for use in transmitting the device-to-device data on the device-to-device data channel within a further transmission period, selecting a feedback period from the plurality of feedback periods based on the further transmission period and the predetermined delay range, determining a code sequence associated with the further subchannel from the plurality of orthogonal code sequences based on a predetermined association between the plurality of orthogonal code sequences of the selected feedback period and the plurality of other subchannels, determining whether the code sequence is to be used for confirming further device-to-device data, determining that the device-to-device data is to be transmitted within the transmission period in response to determining that the code sequence is to be used for confirming the further device-to-device data, and selecting the subchannel from the plurality of subchannels for use in transmitting the device-to-device data to the second terminal device within the transmission period.

In some example embodiments, the first terminal device being caused to select the feedback period from the plurality of feedback periods includes selecting a set of candidate feedback periods from the plurality of feedback periods based on the transmission period and the predetermined delay range, each candidate feedback period having a time difference from the transmission period within the predetermined delay range, and selecting the feedback period from the set of candidate feedback periods.

In some example embodiments, the first terminal device is further caused to receive an indication of time and frequency resources of the device-to-device feedback channel from a network device and determine the plurality of feedback time periods in the time and frequency resources.

In some example embodiments, the first terminal device is further caused to receive an indication of the predetermined delay range from a network device.

In some example embodiments, the time period comprises a time slot.

In some example embodiments, the device-to-device data channel comprises a physical side-chain shared channel and the device-to-device feedback channel comprises a physical side-chain feedback channel.

In some example embodiments, the first terminal device is caused to send the indication of the feedback period to the second terminal device by sending the indication of the feedback period to the second terminal device on a physical side-chain control channel.

In some aspects, a second terminal device includes at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the second terminal device to decode device-to-device data from a first terminal device at a subchannel of a plurality of subchannels of a device-to-device data channel over a transmission period, receive an indication of a feedback period of a plurality of feedback periods from the first terminal device over a device-to-device feedback channel, determine a code sequence from a plurality of orthogonal code sequences of the feedback period based on a predetermined association between the plurality of subchannels and the plurality of orthogonal code sequences of the feedback period, and transmit an acknowledgement of the device-to-device data to the first terminal device over the device-to-device feedback channel using the selected code sequence over the feedback period.

In some example embodiments, the second terminal device is further caused to receive an indication of the predetermined association from a network device.

In some example embodiments, the second terminal device is further caused to receive an indication of time and frequency resources of the device-to-device feedback channel from a network device and to determine the plurality of feedback time periods in the time and frequency resources.

In some example embodiments, the time period comprises a time slot.

In some example embodiments, the second terminal device is caused to receive the indication of the feedback period from the first terminal device by receiving the indication of the feedback period from the first terminal device on a physical side-chain control channel.

In some aspects, a network device includes at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the network device to allocate a plurality of feedback time periods to a device-to-device feedback channel in a resource pool, allocate a plurality of orthogonal code sequences for feedback time periods of the plurality of feedback time periods, determine a delay range between a device-to-device data channel and the device-to-device feedback channel, and associate the plurality of orthogonal code sequences with at least a plurality of subchannels of the device-to-device data channel within a transmission time period based on the delay range.

In some example embodiments, the network device is further caused to send an indication of the delay range to at least a first terminal device.

In some example embodiments, the network device is caused to associate the plurality of orthogonal code sequences with at least the plurality of subchannels by associating the plurality of orthogonal code sequences with at least the plurality of subchannels during the transmission period and with a plurality of other subchannels during a further transmission period.

In some example embodiments, the network device is further caused to send an indication of the association between the plurality of orthogonal code sequences and the plurality of sub-channels to at least the first terminal device and a different second terminal device.

In some example embodiments, the network device is further caused to allocate a frequency band for the device-to-device feedback channel in the resource pool.

In some example embodiments, the allocated frequency band includes one or more physical resource blocks.

In some example embodiments, the time period comprises a time slot.

In some aspects, a method implemented at a first terminal device includes selecting a subchannel from a plurality of subchannels of a device-to-device data channel over a device-to-device data channel in response to device-to-device data to be transmitted to a second terminal device over a transmission period, over the transmission period, selecting a feedback period from a plurality of feedback periods over a device-to-device feedback channel based on the transmission period and a predetermined delay range between the device-to-device data channel and a device-to-device feedback channel, and transmitting an indication of the feedback period to the second terminal device to enable the second terminal device to transmit an acknowledgement of the device-to-device data over the device-to-device feedback channel over the feedback period.

In some example embodiments, the method further comprises determining a code sequence associated with the selected subchannel from a plurality of orthogonal code sequences based on a predetermined association between the plurality of orthogonal code sequences and at least the plurality of subchannels for the feedback period, determining whether the code sequence is to be used to acknowledge additional device-to-device data, and selecting an additional subchannel from the plurality of subchannels for transmitting the device-to-device data to the second terminal device within the transmission period in response to determining that the code sequence is to be used to acknowledge the additional device-to-device data.

In some example embodiments, determining whether the code sequence is to be used to confirm the further device-to-device data includes detecting an indication from a third terminal device indicating that the feedback period is to be used to confirm the further device-to-device data, and determining whether the code sequence is to be used to confirm the further device-to-device data in response to detecting the indication.

In some example embodiments, the method further comprises receiving an indication of the predetermined association from a network device.

In some example embodiments, selecting the subchannel from the plurality of subchannels includes selecting a further subchannel from a plurality of other subchannels for use in transmitting the device-to-device data over the device-to-device data channel within a further transmission time period, selecting a feedback time period from the plurality of feedback time periods based on the further transmission time period and the predetermined delay range, determining a code sequence associated with the further subchannel from the plurality of orthogonal code sequences based on a predetermined association between the plurality of orthogonal code sequences of the selected feedback time period and the plurality of other subchannels, determining whether the code sequence is to be used in acknowledging the further device-to-device data, determining that the device-to-device data is to be transmitted within the transmission time period in response to determining that the code sequence is to be used in acknowledging the further device-to-device data, and selecting the subchannel from the plurality of subchannels for use in transmitting the device-to-device data to the second terminal device within the transmission time period.

In some example embodiments, selecting the feedback time period from the plurality of feedback time periods includes selecting a set of candidate feedback time periods from the plurality of feedback time periods based on the transmission time period and the predetermined delay range, each candidate feedback time period having a time difference from the transmission time period within the predetermined delay range, and selecting the feedback time period from the set of candidate feedback time periods.

In some example embodiments, the method further comprises receiving an indication of time and frequency resources of the device-to-device feedback channel from a network device and determining the plurality of feedback time periods in the time and frequency resources.

In some example embodiments, the method further comprises receiving an indication of the predetermined delay range from a network device.

In some example embodiments, the time period comprises a time slot.

In some example embodiments, transmitting the indication of the feedback period to the second terminal device includes transmitting the indication of the feedback period to the second terminal device on a physical side-chain control channel.

In some aspects, a method implemented at a second terminal device includes decoding device-to-device data from a first terminal device at a subchannel of a plurality of subchannels of a device-to-device data channel over a transmission time period, receiving an indication of a feedback time period of a plurality of feedback time periods from the first terminal device over a device-to-device feedback channel, determining a code sequence from a plurality of orthogonal code sequences of the feedback time period based on a predetermined association between the plurality of subchannels and the plurality of orthogonal code sequences, and transmitting an acknowledgement of the device-to-device data to the first terminal device over the device-to-device feedback channel using the selected code sequence over the feedback time period.

In some example embodiments, the time period comprises a time slot.

In some example embodiments, receiving the indication of the feedback period from the first terminal device includes receiving the indication of the feedback period from the first terminal device on a physical side-chain control channel.

In some aspects, a method implemented at a network device includes allocating a plurality of feedback time periods to a device-to-device feedback channel in a resource pool, allocating a plurality of orthogonal code sequences for feedback time periods of the plurality of feedback time periods, determining a delay range between a device-to-device data channel and the device-to-device feedback channel, and associating the plurality of orthogonal code sequences with at least a plurality of subchannels of the device-to-device data channel within a transmission time period based on the delay range.

In some example embodiments, the method further comprises transmitting an indication of the delay range to at least a first terminal device.

In some example embodiments, associating the plurality of orthogonal code sequences with at least the plurality of subchannels includes associating the plurality of orthogonal code sequences with at least the plurality of subchannels during the transmission period and with a plurality of other subchannels during a further transmission period.

In some example embodiments, the method further comprises transmitting an indication of the association between the plurality of orthogonal code sequences and the plurality of sub-channels to at least the first terminal device and a different second terminal device.

In some example embodiments, the method further comprises allocating a frequency band for the device-to-device feedback channel in the resource pool.

In some example embodiments, the time period comprises a time slot.

In some aspects, an apparatus implemented at a first terminal device includes means for selecting a subchannel from a plurality of subchannels of a device-to-device data channel during a transmission time period in response to device-to-device data to be transmitted to a second terminal device during the transmission time period on a device-to-device data channel, means for selecting a feedback time period from a plurality of feedback time periods on a device-to-device feedback channel based on the transmission time period and a predetermined delay range between the device-to-device data channel and a device-to-device feedback channel, and means for transmitting an indication of the feedback time period to the second terminal device to enable the second terminal device to transmit an acknowledgement of the device-to-device data during the feedback time period on the device-to-device feedback channel.

In some example embodiments, the apparatus further includes means for determining a code sequence associated with the selected subchannel from among a plurality of orthogonal code sequences for the feedback period based on a predetermined association between the plurality of orthogonal code sequences and at least the plurality of subchannels, means for determining whether the code sequence is to be used to acknowledge additional device-to-device data, and means for selecting an additional subchannel from the plurality of subchannels for transmitting the device-to-device data to the second terminal device within the transmission period in response to determining that the code sequence is to be used to acknowledge the additional device-to-device data.

In some example embodiments, the means for determining whether the code sequence is to be used to confirm the further device-to-device data comprises means for detecting an indication from a third terminal device indicating that the feedback period is to be used to confirm the further device-to-device data, and means for determining whether the code sequence is to be used to confirm the further device-to-device data in response to detecting the indication.

In some example embodiments, the apparatus further comprises means for receiving an indication of the predetermined association from a network device.

In some example embodiments, the means for selecting the subchannel from the plurality of subchannels includes means for selecting a further subchannel from a plurality of other subchannels for use in transmitting the device-to-device data over the device-to-device data channel during a further transmission time period, means for selecting a feedback time period from the plurality of feedback time periods based on the further transmission time period and the predetermined delay range, means for determining a code sequence associated with the further subchannel from the plurality of orthogonal code sequences based on a predetermined association between the plurality of orthogonal code sequences of the selected feedback time period and the plurality of other subchannels, means for determining whether the code sequence is to be used in acknowledging further device-to-device data, means for determining that the device-to-device data is to be transmitted during the transmission time period in response to determining that the code sequence is to be used in acknowledging the further device-to-device data, and means for selecting the subchannel from the plurality of subchannels for use in transmitting the device-to-device data to the second terminal device during the transmission time period.

In some example embodiments, the apparatus further includes means for selecting a set of candidate feedback time periods from the plurality of feedback time periods based on the transmission time period and the predetermined delay range, each candidate feedback time period having a time difference from the transmission time period within the predetermined delay range, and means for selecting the feedback time period from the set of candidate feedback time periods.

In some example embodiments, the apparatus further includes means for receiving an indication of time and frequency resources of the device-to-device feedback channel from a network device, and means for determining the plurality of feedback time periods in the time and frequency resources.

In some example embodiments, the apparatus further comprises means for receiving an indication of the predetermined delay range from a network device.

In some example embodiments, the time period comprises a time slot.

In some example embodiments, the means for transmitting the indication of the feedback period to the second terminal device comprises means for transmitting the indication of the feedback period to the second terminal device on a physical side chain control channel.

In some aspects, an apparatus implemented at a second terminal device includes means for decoding device-to-device data from a first terminal device at a subchannel of a plurality of subchannels of a device-to-device data channel over a transmission time period, means for receiving an indication of a feedback time period of a plurality of feedback time periods from the first terminal device over a device-to-device feedback channel, means for determining a code sequence from a plurality of orthogonal code sequences of the feedback time period based on a predetermined association between the plurality of subchannels and the plurality of orthogonal code sequences of the feedback time period, and means for transmitting an acknowledgement of the device-to-device data to the first terminal device over the device-to-device feedback channel using the selected code sequence over the feedback time period.

In some example embodiments, the time period comprises a time slot.

In some example embodiments, the means for receiving the indication of the feedback period from the first terminal device comprises means for receiving the indication of the feedback period from the first terminal device on a physical side chain control channel.

In some aspects, an apparatus implemented at a network device includes means for allocating a plurality of feedback time periods to a device-to-device feedback channel in a resource pool, means for allocating a plurality of orthogonal code sequences for feedback time periods of the plurality of feedback time periods, means for determining a delay range between a device-to-device data channel and the device-to-device feedback channel, and means for associating the plurality of orthogonal code sequences with at least a plurality of sub-channels of the device-to-device data channel within a transmission time period based on the delay range.

In some example embodiments, the apparatus further comprises means for sending an indication of the delay range to at least a first terminal device.

In some example embodiments, the means for associating the plurality of orthogonal code sequences with at least the plurality of subchannels includes means for associating the plurality of orthogonal code sequences with at least the plurality of subchannels during the transmission period and with a plurality of other subchannels during a further transmission period.

In some example embodiments, the apparatus further comprises means for transmitting an indication of the association between the plurality of orthogonal code sequences and the plurality of subchannels to at least the first terminal device and a different second terminal device.

In some example embodiments, the apparatus further comprises means for allocating a frequency band for the device-to-device feedback channel in the resource pool.

In some example embodiments, the time period comprises a time slot.

In some aspects, a computer-readable storage medium includes program instructions stored thereon, which when executed by a processor of a device, cause the device to perform a method according to some example embodiments of the disclosure.

Claims

1. A first terminal device, comprising:

At least one processor, and

At least one memory including computer program code;

the at least one memory and the computer program code are configured to, with the at least one processor, cause the first terminal device to:

Selecting a sub-channel from a plurality of sub-channels of a device-to-device data channel during a transmission period in response to device-to-device data to be transmitted to a second terminal device over the device-to-device data channel during the transmission period;

Selecting a feedback period from a plurality of feedback periods on a device-to-device feedback channel based on the transmission period and a predetermined delay range between the device-to-device data channel and the device-to-device feedback channel, and

And sending an indication of the feedback period to the second terminal device to enable the second terminal device to send an acknowledgement of the device-to-device data over the device-to-device feedback channel for the feedback period.

2. The first terminal device of claim 1, wherein the first terminal device is further caused to:

determining a code sequence associated with the selected subchannel from among a plurality of orthogonal code sequences of the feedback period based on a predetermined association between the plurality of orthogonal code sequences and at least the plurality of subchannels;

Determining whether the code sequence is to be used to confirm additional device-to-device data;

in response to determining that the code sequence is to be used to acknowledge the further device-to-device data, a further sub-channel is selected from the plurality of sub-channels for transmitting the device-to-device data to the second terminal device within the transmission period.

3. The first terminal device of claim 2, wherein the first terminal device is caused to determine whether the code sequence is to be used to confirm the further device-to-device data by:

Detecting an indication from a third terminal device indicating that the feedback period is to be used for acknowledging the further device-to-device data, and

In response to detecting the indication, determining whether the code sequence is to be used to confirm the further device-to-device data.

4. The first terminal device of claim 2, wherein the plurality of orthogonal code sequences are associated with at least the plurality of subchannels during the transmission period and with a plurality of other subchannels during a further transmission period.

5. The first terminal device of claim 4, wherein

The delay range includes at least a first delay sub-range and a second delay sub-range, and

The time difference between the transmission period and the feedback period is within the first delay sub-range and the time difference between the further transmission period and the feedback period is within the second delay sub-range.

6. The first terminal device of claim 2, wherein the first terminal device is further caused to:

An indication of the predetermined association is received from a network device.

7. The first terminal device of claim 1, wherein the first terminal device is caused to select the subchannel from the plurality of subchannels by:

selecting a further sub-channel from a plurality of other sub-channels for transmission of the device-to-device data over the device-to-device data channel during a further transmission period;

Selecting a feedback period from the plurality of feedback periods based on the further transmission period and the predetermined delay range;

Determining a code sequence associated with the further subchannel from the plurality of orthogonal code sequences based on a predetermined association between the plurality of orthogonal code sequences of the selected feedback period and the plurality of other subchannels;

determining whether the code sequence is to be used to acknowledge additional device-to-device data;

in response to determining that the code sequence is to be used to acknowledge the further device-to-device data, determining that the device-to-device data is to be transmitted within the transmission time period, and

The sub-channel is selected from the plurality of sub-channels for transmitting the device-to-device data to the second terminal device during the transmission period.

8. The first terminal device of claim 1, wherein the first terminal device is caused to select the feedback period from the plurality of feedback periods comprises:

Selecting a set of candidate feedback time periods from the plurality of feedback time periods based on the transmission time period and the predetermined delay range, a time difference between each candidate feedback time period and the transmission time period being within the predetermined delay range, and

The feedback time period is selected from the set of candidate feedback time periods.

9. The first terminal device of claim 1, wherein the first terminal device is further caused to:

Receiving an indication of time and frequency resources of said device-to-device feedback channel from a network device, and

The plurality of feedback time periods are determined in the time and frequency resources.

10. The first terminal device of claim 1, wherein the first terminal device is further caused to:

An indication of the predetermined delay range is received from a network device.

11. The first terminal device of claim 1, wherein the time period comprises a time slot.

12. The first terminal device of claim 1, wherein the device-to-device data channel comprises a physical side-chain shared channel and the device-to-device feedback channel comprises a physical side-chain feedback channel.

13. The first terminal device of claim 12, wherein the first terminal device is caused to send the indication of the feedback period to the second terminal device by:

And sending the indication of the feedback time period to the second terminal equipment on a physical side chain control channel.

14. A second terminal device comprising:

At least one processor, and

At least one memory including computer program code;

the at least one memory and the computer program code are configured to, with the at least one processor, cause the second terminal device to:

Decoding device-to-device data from the first terminal device at a subchannel of a plurality of subchannels of the device-to-device data channel over a transmission period;

Receiving an indication of a feedback period of a plurality of feedback periods from the first terminal device on a device-to-device feedback channel;

determining a code sequence from a plurality of orthogonal code sequences of the feedback period based on a predetermined association between the plurality of subchannels and the plurality of orthogonal code sequences, and

An acknowledgement of the device-to-device data is sent to the first terminal device over the device-to-device feedback channel using the selected code sequence for the feedback period.

15. The second terminal device of claim 14, wherein the plurality of orthogonal code sequences are associated with at least the plurality of subchannels during the transmission period and with a plurality of other subchannels during a further transmission period.

16. The second terminal device of claim 14, wherein the second terminal device is further caused to:

17. The second terminal device of claim 14, wherein the second terminal device is further caused to:

18. The second terminal device of claim 14, wherein the time period comprises a time slot.

19. The second terminal device of claim 14, wherein the device-to-device data channel comprises a physical side-chain shared channel and the device-to-device feedback channel comprises a physical side-chain feedback channel.

20. The second terminal device of claim 19, wherein the second terminal device is caused to receive the indication of the feedback period from the first terminal device by:

The indication of the feedback period is received from the first terminal device on a physical side chain control channel.

21. A network device, comprising:

At least one processor, and

At least one memory including computer program code;

The at least one memory and the computer program code are configured to, with the at least one processor, cause the network device to:

allocating a plurality of feedback time periods to the device-to-device feedback channel in the resource pool;

allocating a plurality of orthogonal code sequences for a feedback period of the plurality of feedback periods;

Determining a delay range between a device-to-device data channel and said device-to-device feedback channel, and

The plurality of orthogonal code sequences are associated with at least a plurality of sub-channels of the device-to-device data channel for a transmission period based on the delay range.

22. The network device of claim 21, wherein the network device is further caused to:

An indication of the delay range is sent to at least a first terminal device.

23. The network device of claim 21, wherein the network device is caused to associate the plurality of orthogonal code sequences with at least the plurality of subchannels by:

The plurality of orthogonal code sequences are associated with at least the plurality of subchannels during the transmission time period and with a plurality of other subchannels during further transmission time periods.

24. The network device of claim 23, wherein

25. The network device of claim 22, wherein the network device is further caused to:

an indication of the association between the plurality of orthogonal code sequences and the plurality of sub-channels is sent to at least the first terminal device and a different second terminal device.

26. The network device of claim 21, wherein the network device is further caused to:

A frequency band is allocated in the resource pool for the device-to-device feedback channel.

27. The network device of claim 21, wherein the allocated frequency band comprises one or more physical resource blocks.

28. The network device of claim 21, wherein the time period comprises a time slot.

29. The network device of claim 21, wherein the device-to-device data channel comprises a physical side-chain shared channel and the device-to-device feedback channel comprises a physical side-chain feedback channel.

30. A method implemented at a first terminal device, comprising:

31. The method of claim 30, further comprising:

32. The method of claim 31, wherein determining whether the code sequence is to be used to confirm the additional device-to-device data comprises:

33. The method of claim 31, wherein the plurality of orthogonal code sequences are associated with at least the plurality of subchannels during the transmission period and with a plurality of other subchannels during a further transmission period.

34. The method of claim 33, wherein

35. The method of claim 31, further comprising:

36. The method of claim 30, wherein selecting the subchannel from the plurality of subchannels comprises:

37. The method of claim 30, wherein selecting the feedback period from the plurality of feedback periods comprises:

38. The method of claim 30, further comprising:

39. The method of claim 30, further comprising:

40. The method of claim 30, wherein the time period comprises a time slot.

41. The method of claim 30, wherein the device-to-device data channel comprises a physical side-chain shared channel and the device-to-device feedback channel comprises a physical side-chain feedback channel.

42. The method of claim 41, wherein sending the indication of the feedback period to the second terminal device comprises:

43. A method implemented at a second terminal device, comprising:

44. The method of claim 43, wherein the plurality of orthogonal code sequences are associated with at least the plurality of subchannels during the transmission time period and with a plurality of other subchannels during further transmission time periods.

45. The method of claim 43, further comprising:

46. The method of claim 43, further comprising:

47. The method of claim 43, wherein the time period comprises a time slot.

48. The method of claim 43, wherein the device-to-device data channel comprises a physical side-chain shared channel and the device-to-device feedback channel comprises a physical side-chain feedback channel.

49. The method of claim 48, wherein receiving the indication of the feedback period of time from the first terminal device comprises:

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

51. The method of claim 50, further comprising:

An indication of the delay range is sent to at least a first terminal device.

52. The method of claim 50, wherein associating the plurality of orthogonal code sequences with at least the plurality of subchannels comprises:

53. The method of claim 52, wherein

54. The method of claim 51, further comprising:

55. The method of claim 50, further comprising:

56. The method of claim 55, wherein the allocated frequency band comprises one or more physical resource blocks.

57. The method of claim 50, wherein the time period comprises a time slot.

58. The method of claim 50, wherein the device-to-device data channel comprises a physical side-chain shared channel and the device-to-device feedback channel comprises a physical side-chain feedback channel.

59. An apparatus for communication, comprising:

Means for selecting a subchannel from a plurality of subchannels of a device-to-device data channel during a transmission time period in response to device-to-device data to be transmitted to a second terminal device over the device-to-device data channel during the transmission time period;

Means for selecting a feedback period from a plurality of feedback periods on a device-to-device feedback channel based on the transmission period and a predetermined delay range between the device-to-device data channel and the device-to-device feedback channel, and

And means for sending an indication of the feedback period to the second terminal device to enable the second terminal device to send an acknowledgement of the device-to-device data over the device-to-device feedback channel for the feedback period.

60. An apparatus for communication, comprising:

means for decoding device-to-device data from the first terminal device at a subchannel of a plurality of subchannels of the device-to-device data channel over a transmission period;

means for receiving an indication of a feedback period of a plurality of feedback periods from the first terminal device on a device-to-device feedback channel;

means for determining a code sequence from a plurality of orthogonal code sequences of the feedback period based on a predetermined association between the plurality of subchannels and the plurality of orthogonal code sequences, and

Means for transmitting an acknowledgement of the device-to-device data to the first terminal device using the selected code sequence over the device-to-device feedback channel for the feedback period.

61. An apparatus for communication, comprising:

Means for allocating a plurality of feedback time periods to a device-to-device feedback channel in a resource pool;

means for allocating a plurality of orthogonal code sequences for a feedback period of the plurality of feedback periods;

Means for determining a delay range between a device-to-device data channel and the device-to-device feedback channel, and

The apparatus further includes means for associating the plurality of orthogonal code sequences with at least a plurality of subchannels of the device-to-device data channel during a transmission time period for the delay range.

62. A computer readable storage medium comprising program instructions stored thereon, which when executed by a processor of a device, cause the device to perform the method of any of claims 30 to 42.

63. A computer readable storage medium comprising program instructions stored thereon, which when executed by a processor of a device, cause the device to perform the method of any of claims 43 to 49.

64. A computer readable storage medium comprising program instructions stored thereon, which when executed by a processor of a device, cause the device to perform the method of any of claims 50 to 58.