A method performed by a first terminal device, and the first terminal device

Abstract

This invention provides a communication method, apparatus, and computer-readable medium that avoid resource collisions when discontinuous reception (DRX) is configured in V2X (vehicle-to-everything) communication. [Solution] The method involves a first terminal device receiving first sidelink control information and a first reference signal associated with the first sidelink control information from a second terminal device during the on-duration of a discontinuous reception cycle, and determining available candidate resources in the resource selection window for a first sidelink transmission based on at least the first sidelink control information and the first reference signal, in accordance with the determination that there is an overlapping period between the off-duration of the discontinuous reception cycle and the sensing window.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to the field of telecommunications, and more particularly to a communication method, apparatus, and computer-readable medium for resource selection in discontinuous reception (DRX).

Background Art

[0002] DRX is a method of reducing power consumption by a communication device receiving information from another communication device discontinuously. DRX may be set for a terminal device in a vehicle-to-everything (V2X) use case, or for a terminal device in a public safety and commercial use case where it is necessary to minimize power consumption.

[0003] In V2X communication, a terminal device may autonomously select a resource within a resource pool for sidelink transmission by performing full sensing or partial sensing. When DRX is set, the terminal device may become active during the on-duration of a DRX cycle and monitor and decode a control channel. During the off-duration of the DRX cycle, the terminal device may enter an inactive state where it does not perform monitoring and decoding. Therefore, the terminal device may obtain inaccurate sensing results. As a result, resource collisions may occur.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Generally, exemplary embodiments of the present disclosure provide a communication method, apparatus, and computer-readable medium.

Means for Solving the Problems

[0005] In a first embodiment, a communication method is provided. The method includes, during the on-duration of a discontinuous reception cycle, a first terminal device receiving from a second terminal device first sidelink control information and a first reference signal associated with the first sidelink control information. The method includes, in accordance with the determination that there is an overlap period between the off-duration of the discontinuous reception cycle and a sensing window, determining available candidate resources in a resource selection window for a first sidelink transmission, based on at least the first sidelink control information and the first reference signal.

[0006] In a second embodiment, a method of communication is provided. The method includes determining in a first terminal device whether there is an overlap period between the off-duration of a discontinuous reception cycle and a sensing window. The method further includes, in accordance with the determination that an overlap period exists, determining available candidate resources in the resource selection window for a first sidelink transmission, based on information about resource selection received from a third terminal device.

[0007] In a third embodiment, a method of communication is provided. The method includes receiving sidelink control information and a reference signal from a second terminal device within a second sensing window, in accordance with the determination that there is an overlap period between the off duration of a first discontinuous reception cycle and a first sensing window. The second sensing window is within the on duration of a second discontinuous reception cycle following the first discontinuous reception cycle. The method further includes determining available candidate resources in a resource selection window for a first sidelink transmission, based on at least the first sidelink control information and the reference signal. The resource selection window is after the second sensing window and within the on duration.

[0008] In a fourth embodiment, a terminal device is provided. The terminal device includes a processor and a memory for storing instructions. The memory and the instructions are configured to cause the terminal device to perform the method according to the first embodiment using the processor.

[0009] In a fifth embodiment, a terminal device is provided. The terminal device comprises a processor and a memory storing instructions. The memory and the instructions are configured to cause the terminal device to execute the method according to the second embodiment using the processor.

[0010] In a sixth embodiment, a terminal device is provided. The terminal device includes a processor and a memory for storing instructions. The memory and the instructions are configured to cause the terminal device to perform the method according to the third embodiment using the processor.

[0011] In a seventh embodiment, a computer-readable medium storing instructions is provided. When the instructions are executed on at least one processor of the device, the device is caused to perform the method according to the first embodiment.

[0012] In an eighth embodiment, a computer-readable medium storing instructions is provided. When the instructions are executed on at least one processor of the device, the device is caused to perform the method according to the second embodiment.

[0013] In a ninth embodiment, a computer-readable medium storing instructions is provided. When the instructions are executed on at least one processor of the device, the device is caused to perform the method according to the third embodiment.

[0014] It should be understood that the summary portion of the invention is not intended to identify any important or fundamental features of the embodiments of this disclosure, nor to limit the scope of this disclosure. Other features of this disclosure will be readily apparent from the following description. [Brief explanation of the drawing]

[0015] By further elaborating several embodiments of the present disclosure in the drawings, the above and other objects, features, and advantages of the present disclosure will be made more apparent.

[0016] [Figure 1] It is a diagram showing an exemplary communication network capable of implementing embodiments of the present disclosure.

[0017] [Figure 2] It is an exemplary signaling diagram showing an exemplary process for resource selection according to some embodiments of the present disclosure.

[0018] [Figure 3A] It is a schematic diagram showing partial sensing and DRX setting according to some embodiments of the present disclosure.

[0019] [Figure 3B] It is a schematic diagram showing partial sensing and DRX setting according to some other embodiments of the present disclosure.

[0020] [Figure 4] It is a schematic diagram showing sensing and DRX setting according to some embodiments of the present disclosure.

[0021] [Figure 5] It is a schematic diagram showing sensing and DRX setting according to some other embodiments of the present disclosure.

[0022] [Figure 6] It is a schematic diagram showing sensing and DRX setting according to still other embodiments of the present disclosure.

[0023] [Figure 7] It is a schematic diagram showing sensing and DRX setting according to still other embodiments of the present disclosure.

[0024] [Figure 8]This is an exemplary signaling diagram illustrating an exemplary process for resource selection according to some other embodiments of the present disclosure.

[0025] [Figure 9] This is an exemplary signaling diagram illustrating an exemplary process for resource selection according to yet another embodiment of the present disclosure.

[0026] [Figure 10] This is a schematic diagram illustrating partial sensing and DRX settings according to yet another embodiment of the present disclosure.

[0027] [Figure 11] This is a flowchart illustrating an exemplary method according to some embodiments of the present disclosure.

[0028] [Figure 12] This is a flowchart illustrating an exemplary method relating to some other embodiments of the present disclosure.

[0029] [Figure 13] This is a flowchart illustrating an exemplary method according to yet another embodiment of the present disclosure.

[0030] [Figure 14] This is a schematic block diagram of a device suitable for implementing an embodiment of the present disclosure.

[0031] In the diagram, identical or similar reference numbers represent identical or similar elements. [Modes for carrying out the invention]

[0032] Herein, the principles of the disclosure will be explained with reference to several exemplary embodiments. These embodiments are provided for illustrative purposes only and should be understood as helping those skilled in the art to understand and implement the disclosure, and should not be considered as implying any limitation on the scope of the disclosure. The disclosures described herein can be implemented in a variety of ways other than those described below.

[0033] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art.

[0034] As used in this text, the term “terminal device” means any device having wireless or wired communication capabilities. Examples of terminal devices include, but are not limited to, user devices (UEs), personal computers, desktop computers, mobile phones, cellular phones, smartphones, personal digital assistants (PDAs), portable computers, tablets, wearable devices, Internet of Things (IoT) devices, any Internet of Things (IoE) devices, machine-type communication (MTC) devices, and in-vehicle devices for V2X communication. In V2X, the “X” represents pedestrians, vehicles or infrastructure / networks, or image acquisition devices such as digital cameras, game consoles, music storage and playback devices, or internet-connected home appliances that enable wireless or wired internet access and browsing.

[0035] As used in this text, the terms “network device” or “base station” (BS) mean a device capable of providing or hosting a cell or coverage on which terminal devices can communicate. Examples of network devices include, but are not limited to, Node B (NodeB or NB), Evolutionary Node B (eNodeB or eNB), Next Generation Node B (gNB), Transmit / Receive Point (TRP), Remote Radio Unit (RRU), Radio Head (RH), Remote Radio Head (RRH), Femtonode, piconode, and other low-power nodes.

[0036] As used herein, the singular "one" and "the foregoing" also include the plural unless explicitly indicated in the context. The term "including" and its variations should be understood as an open-ended term meaning "including, but not limited to." The term "based on" should be understood as "at least partially based on." The terms "several embodiments" and "embodiment" should be understood as "at least several embodiments." The term "another embodiment" should be understood as "at least one other embodiment." Terms such as "first," "second," etc., may refer to different or identical subjects. The following may include other explicit and implicit definitions.

[0037] In some examples, values, procedures, or devices are referred to as “best,” “lowest,” “highest,” “minimum,” “maximum,” etc. Such descriptions are intended to show that a choice can be made from among many used functional alternatives, and it will be understood that such a choice does not need to be better, smaller, higher, or otherwise more desirable than other choices.

[0038] During the off-duration of the DRX cycle, the terminal device may enter an inactive state where it does not perform monitoring and decryption. Therefore, the terminal device may obtain inaccurate sensing results. As a result, resource conflicts may occur.

[0039] Embodiments of this disclosure provide a solution for resource selection in DRX to solve the above-mentioned problems and one or more other potential problems. According to this solution, a first terminal device receives sidelink control information (SCI) and a reference signal associated with the SCI from a second terminal device during the on-duration of a DRX cycle. If the first terminal device determines that there is an overlap period between the off-duration of the discontinuous reception cycle and the sensing window, the first terminal device determines, based at least on the SCI and the reference signal, an available candidate resource in the resource selection window for sidelink transmission. Thus, the first terminal device can obtain accurate sensing results. As a result, resource collisions can be avoided.

[0040] Figure 1 is a schematic diagram showing an exemplary communication network 100 capable of implementing embodiments of the present disclosure. As shown in Figure 1, the communication network 100 may include a first terminal device 110, a second terminal device 120, and a third terminal device. It should be understood that the communication network 100 may further include network devices (not shown). The network devices may communicate with the first terminal device 110, the second terminal device 120, and the third terminal device 130 via their respective wireless communication channels. It should be understood that the number of devices in Figure 1 is given for illustrative purposes only and does not imply any limitation to the present disclosure. The communication network 100 may include any suitable number of network devices and / or terminal devices suitable for implementing embodiments of the present disclosure.

[0041] Figure 1 shows a vehicle in which a first terminal device 110, a second terminal device 120, and a third terminal device 130 enable V2X communication. It should be understood that the embodiments of this disclosure are also applicable to other terminal devices other than vehicles, such as mobile phones, sensors, etc.

[0042] Communication in the communication network 100 may comply with any appropriate standard, including but not limited to, the Global System for Mobile Communications (GSM), Long-Term Evolution (LTE), LTE-Evolution, LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA®), Code Division Multiple Access (CDMA), GSM Edge Radio Access Network (GERAN), and Machine Type Communications (MTC). Furthermore, communication may be performed in accordance with any generation of communication protocol currently known or to be developed in the future. Examples of communication protocols include, but are not limited to, first-generation (1G), second-generation (2G), 2.5G, 2.75G, third-generation (3G), fourth-generation (4G), 4.5G, and fifth-generation (5G) communication protocols.

[0043] Figure 2 is an exemplary signaling diagram showing an exemplary process 200 for resource selection according to some embodiments of the present disclosure. As shown in Figure 2, the process 200 may involve a first terminal device 110 and a second terminal device 120, as shown in Figure 1. The process 200 may include additional operations not shown, and / or some operations shown may be omitted, and it should be understood that the scope of the present disclosure is not limited in this respect. Furthermore, although presented herein primarily as being performed sequentially, it will be understood that at least some of the operations of the process 200 may be performed simultaneously or in a different order than that shown in Figure 2.

[0044] As shown in Figure 2, the first terminal device 110 receives the first SCI and the first reference signal associated with the first SCI from the second terminal device 120 during the ON duration of the DRX cycle (210).

[0045] In some exemplary embodiments, the first terminal device 110 may receive a first SCI on the Physical Sidelink Control Channel and a first reference signal on the Physical Sidelink Control Channel or an associated Physical Sidelink Shared Channel.

[0046] The first terminal device 110 determines whether there is an overlapping period between the off-duration time of the discontinuous reception cycle and the sensing window (220).

[0047] If the first terminal device 110 determines that an overlapping period exists, the first terminal device 110 determines available candidate resources in the resource selection window for the first sidelink transmission, based at least on the first SCI and the first reference signal (230). In this way, the first terminal device 110 can obtain accurate sensing results. As a result, resource collisions between the first terminal device 110 and the second terminal device 120 can be avoided.

[0048] In some exemplary embodiments, the first reference signal may include a demodulated reference signal (DMRS). The first terminal device 110 may decode the first SCI by channel estimation using the DMRS.

[0049] In some exemplary embodiments, if the first terminal device 110 is configured to include both partial sensing and DRX, the first terminal device 110 may be expected to be configured to include candidate sensing occasions that fall within only the ON duration of the DRX cycle. This will be illustrated with reference to Figure 3A.

[0050] Figure 3A is a schematic diagram illustrating partial sensing and DRX according to some embodiments of the present disclosure. As shown in Figure 3A, the first terminal device 110 is configured to include partial sensing. To perform partial sensing, the protocol layer of the first terminal device 110, which is higher than the physical layer of the first terminal device 110, configures the physical layer to have a minimum number of candidate resources to be selected in the resource selection window 310. Hereinafter, for discussion purposes, the protocol layer above the physical layer will also be referred to as the upper layer. For example, the upper layer may include a Media Access Control (MAC) layer or a Radio Resource Control (RRC) layer. This number may be any value, and the scope of the present disclosure is not limited thereto. For example, in the example shown in Figure 3A, the number of candidate resources is 1. Therefore, the physical layer determines one candidate resource 311 in the resource selection window 310.

[0051] Additionally, the upper layer configures the physical layer to have candidate sensing occasions within the sensing window 320. In some exemplary embodiments, candidate sensing occasions may be indicated by a parameter gapCandidateSensing from the upper layer. The parameter gapCandidateSensing may be in the form of a bitmap. Bits in the bitmap are set to "1" to indicate that the corresponding slot is set as a candidate sensing occasion. Conversely, bits in the bitmap are set to "0" to indicate that the corresponding slot is not set as a candidate sensing occasion. For example, in the example shown in Figure 3A, the bitmap may be "11100", where "11100" indicates that slots 321, 322, and 323 are set as candidate sensing occasions, and slots 324 and 325 are not set as candidate sensing occasions.

[0052] Note that the bitmap containing the five bits described above is only an example. The bitmap may contain more or fewer bits depending on the number of candidate sensing occasions.

[0053] The first terminal device 110 is also configured to include a DRX. For example, a DRX cycle 330 includes an on duration 331 and an off duration 332. Candidate sensing occasions 321, 322, and 323 are all within the on duration 331. There is an overlap period 333 between the off duration 332 and the sensing window 320. In candidate sensing occasions 321, 322, and 323, the first terminal device 110 monitors the sidelink control channel to receive the first SCI and the first reference signal from the second terminal device 120.

[0054] Furthermore, the first terminal device 110 determines available candidate resources in the resource selection window 310 based on at least the first SCI and the first reference signal. For example, the first terminal device 110 may determine the resource reservation period P_rx of the second terminal device 120 based on the first SCI. Furthermore, the first terminal device 110 may determine resource 311 based on sensing occasions 321, 322, and 323 and the resource reservation period P_rx. In addition, the first terminal device 110 may measure the reference signal received power (RSRP) of the first reference signal. The first terminal device 110 may then compare the measured RSRP with a threshold RSRP. If the measured RSRP is higher than the threshold RSRP, the first terminal device 110 may determine that one or more subchannels in resource 311 are reserved by the second terminal device 120 for the second terminal device 120's sidelink transmission occurring within the corresponding one or more subchannels in slot resource 321, 322, or 323. Conversely, the first terminal device 110 may determine a different resource in resource 311 from the one or more subchannels in resource 311 as an available candidate resource for the first sidelink transmission of the first terminal device 110.

[0055] In the example shown in Figure 3A, the first terminal device 110 does not perform sensing or partial sensing during the off-duration period 332, thus reducing the power consumption of the first terminal device 110.

[0056] Figure 3B is a schematic diagram showing partial sensing and DRX according to some other embodiments of the present disclosure. Unlike the example shown in Figure 3A, in the example shown in Figure 3B, some of the candidate sensing occasions indicated by the bitmap from the upper layer are within the on duration 331, and others are within the off duration 332. For example, the bitmap may be "11100", where "11100" indicates that slots 321, 322, and 326 are set as candidate sensing occasions, and slots 324 and 325 are not set as candidate sensing occasions. Of the candidate sensing occasions 321, 322, and 326, candidate sensing occasions 321 and 322 are within the on duration 331, and sensing occasion 326 is within the off duration 332. In such an example, only during candidate sensing occasions 321 and 322 within the ON duration 331, the first terminal device 110 monitors the sidelink control channel to receive the first SCI and the first reference signal from the second terminal device 120.

[0057] Furthermore, in the example shown in Figure 3B, the physical layer of the first terminal device 110 may transmit an instruction to the upper layer indicating that the candidate sensing occasion 326 is unavailable during the overlap period 333. For example, this instruction may be in the form of a bitmap. The bits in the bitmap are set to "1" to indicate that the corresponding candidate sensing occasion is unavailable. For example, in the example shown in Figure 3B, the bitmap may be "00100" to indicate that the candidate sensing occasion 326 is unavailable.

[0058] Upon receiving the instruction, the upper layer may avoid indicating the third bit as a candidate sensing occasion for a later transmission. Thus, the terminal device can obtain accurate sensing results.

[0059] In some exemplary embodiments, the first terminal device 110 may monitor the sidelink control channel during the off-duration of the DRX cycle in order to obtain accurate sensing results. This will be explained with reference to Figure 4.

[0060] Figure 4 is a schematic diagram illustrating sensing and DRX configuration according to some embodiments of the present disclosure. As shown in Figure 4, on resource 341, the first terminal device 110 monitors the sidelink control channel to receive the first SCI and the first reference signal from the second terminal device 120. Based on the first SCI and the first reference signal, the first terminal device 110 determines the first resource 342 reserved by the second terminal device 120 for the second sidelink transmission.

[0061] If the first terminal device 110 determines that the first resource 342 is within the off-duration 332, the first terminal device 110 receives a second SCI and a second reference signal associated with the second SCI from the second terminal device 120 on the first resource 342. Furthermore, the first terminal device 110 determines available candidate resources based on the second SCI and the second reference signal. For example, the first terminal device 110 may determine, based on the second SCI and the second reference signal, that resource 343 in the resource selection window 310 is reserved by the second terminal device 120. Therefore, the first terminal device 110 determines a resource different from resource 343 in the resource selection window as an available candidate resource.

[0062] In some exemplary embodiments, the first terminal device 110 may remain active from the start of the off-duration 332 until the end of the first resource 342 in order to receive the second SCI and the second reference signal on the first resource 342. In other words, the first terminal device 110 may remain awake from the start of the off-duration 332 until the end of the first resource 342 in order to monitor the sidelink control channel. Thus, if any other SCI is transmitted by the second terminal device 120, the other SCI can be detected by the first terminal device 110.

[0063] Alternatively, the first terminal device 110 may switch from an inactive state to an active state on the first resource 342 to monitor the sidelink control channel in order to receive the second SCI and the second reference signal on the first resource 342. In other words, during the off-duration 332, the first terminal device 110 may wake up only on the first resource 342 to monitor the sidelink control channel and enter a sleep state after the first resource 342 has finished. In this way, the power consumption of the first terminal device 110 can be reduced.

[0064] In some exemplary embodiments, it may be assumed that the possible continuous resource reservations of the second terminal device 120 are within the off-duration. This will be explained with reference to Figure 5.

[0065] Figure 5 is a schematic diagram illustrating sensing and DRX configuration according to some other embodiments of the present disclosure. Similar to the example shown in Figure 4, in the example shown in Figure 5, the first terminal device 110 determines a second resource 344 reserved by the second terminal device 120 for a third sidelink transmission, based on a first SCI and a first reference signal received on resource 341.

[0066] Unlike the example shown in Figure 4, in the example shown in Figure 5, the first terminal device 110 does not monitor the sidelink control channel during the off-duration 332 of the DRX cycle 330. Instead, if the first terminal device 110 determines that the second resource 344 is within the off-duration 332, the first terminal device 110 determines any contiguous resources that may be reserved by the second terminal device 120 based on the first SCI received on resource 341, the first reference signal, the start of the off-duration, and the end of the resource selection window 310.

[0067] For example, the first terminal device 110 determines the resource reservation period P_rx of the second terminal device 120 based on the first SCI received on resource 341. Then, the first terminal device 110 determines the possible consecutive resources reserved by the second terminal device 120 based on the sum of resource 341 and P_rx, the sum of resource 341 and 2*P_rx, ..., and the sum of resource 341 and Q*P_rx. Here, Q = |T_scal / P_rx|, where T_scal represents the duration from the start of the off-duration (represented as T_OFF in Figure 5) to the end of the resource selection window 310 (represented as T_END in Figure 5). In the example shown in Figure 5, the possible consecutive resources reserved by the second terminal device 120 include resources 344, 345, and 346.

[0068] If the first terminal device 110 determines that at least one of the contiguous resources is within the resource selection window 310, the first terminal device 110 determines a resource within the resource selection window 310 that is different from the at least one resource as an available candidate resource. In the example shown in Figure 5, the at least one of the contiguous resources within the resource selection window 310 includes resource 346 (also referred to as the third resource). In this case, the first terminal device 110 determines a resource within the resource selection window 310 that is different from resource 346 as an available candidate resource.

[0069] In some exemplary embodiments, assume that for any resource m during the off-duration, all resources represented by m+P_allowed located in the resource selection window are reserved by the second terminal device 120, where P_allowed represents each of the resource reservation periods pre-configured to be allowed for the resource pool. Furthermore, the first terminal device 110 determines resources in the resource selection window 310 that are different from the reserved resources 346 as available candidate resources. This will be illustrated with reference to Figure 6.

[0070] Figure 6 is a schematic diagram showing sensing and DRX configuration according to yet another embodiment of the present disclosure. In the example shown in Figure 6, the first terminal device 110 may determine at least one fourth resource based on the resource 347 within the off-duration 332 and at least one pre-set resource reservation period. For example, the at least one pre-set resource reservation period may include 10ms, 20ms, 30ms, etc. The first terminal device 110 may determine a contiguous resource that may be reserved by the second terminal device 120 based on the sum of the resource 347 and each of the at least one pre-set resource reservation periods.

[0071] If the first terminal device 110 determines that at least one fourth resource is present in the resource selection window, the first terminal device 110 determines a resource in the resource selection window 310 that is different from the at least one fourth resource as an available candidate resource. In the example shown in Figure 6, the at least one fourth resource may include resource 348. Therefore, the first terminal device 110 determines a resource in the resource selection window 310 that is different from resource 348 as an available candidate resource.

[0072] In the example shown in Figure 6, the first terminal device 110 may also determine at least one fourth resource based on the resources 349 within the off-duration 332 and the at least one preset resource reservation period. For example, the first terminal device 110 may determine a sequence of resources that may be reserved by the second terminal device 120 based on the sum of the resources 349 and each of the at least one preset resource reservation period.

[0073] If the first terminal device 110 determines that at least one fourth resource is present in the resource selection window, the first terminal device 110 determines a resource in the resource selection window 310 that is different from the at least one fourth resource as an available candidate resource. In the example shown in Figure 6, the at least one fourth resource may further include resource 350. Therefore, the first terminal device 110 determines a resource in the resource selection window 310 that is different from resource 350 as an available candidate resource.

[0074] In some exemplary embodiments, if the first terminal device 110 determines that the priority of the data transmitted by the first terminal device 110 is higher than the threshold priority, the first terminal device 110 determines the at least one fourth resource.

[0075] In some other exemplary embodiments, if the first terminal device 110 determines that the channel congestion rate is lower than a threshold rate, the first terminal device 110 determines the at least one fourth resource.

[0076] In another exemplary embodiment, if the first terminal device 110 determines that the off duration is less than a threshold duration, the first terminal device 110 determines the at least one fourth resource.

[0077] In another exemplary embodiment, if the first terminal device 110 determines that the number of the at least one preset resource reservation period is less than a threshold number, the first terminal device 110 determines the at least one fourth resource.

[0078] In some exemplary embodiments, SCI transmission is not permitted during the off-duration so that no missed reserved SCI detections occur during the off-duration. In such exemplary embodiments, a dedicated resource pool is configured for the power-saving terminal device. For example, if the first terminal device 110 and the second terminal device 120 are power-saving terminal devices, a first resource pool for transmission and a second resource pool for reception are configured for the first terminal device 110 and the second terminal device 120, respectively. The DRX settings are pool-specific. In other words, the on-duration of the first pool is aligned with the on-duration of the second pool, and the off-duration of the first pool is aligned with the off-duration of the second pool.

[0079] In this exemplary embodiment, the first terminal device 110 and the second terminal device 120 may select only one or more resources from the first pool for transmission and one or more resources from the second pool for reception. This will be explained with reference to Figure 7.

[0080] Figure 7 is a schematic diagram showing sensing and DRX settings according to yet another embodiment of the present disclosure. In the example shown in Figure 7, an on duration 331 is set for the second pool and an off duration 332 is set for the second pool. The first terminal device 110 may receive the first SCI from the second terminal device 120 on resource 351 or 353 in the second pool.

[0081] The ON duration 331 is also set for the first pool (not shown), and the OFF duration 332 is also set for the first pool (not shown). The second terminal device 120 may transmit the first SCI on the resources in the first pool.

[0082] The first terminal device 110 may determine that resource 352 is reserved by the second terminal device 120 based on the first SCI and first reference signal received on resource 351. Therefore, the first terminal device 110 determines a resource different from resource 352 in the resource selection window 310 as an available candidate resource.

[0083] Alternatively, the first terminal device 110 may determine that resource 354 is reserved by the second terminal device 120 based on the first SCI and first reference signal received on resource 352. Therefore, the first terminal device 110 determines a resource different from resource 354 in the resource selection window 310 as an available candidate resource.

[0084] In some exemplary embodiments, the on duration 331 and the off duration 332 are set using a first slot index and a second slot index with respect to the reference slot, respectively.

[0085] In some exemplary embodiments, the reference slot may be common to both the first terminal device 110 and the second terminal device 120. In some exemplary embodiments, the reference slot includes a first start slot for the serving cell's start system frame for both the first terminal device 110 and the second terminal device 120. For example, the reference slot includes slot #0 of the radio frame corresponding to the serving cell's System Frame Number (SFN) 0. Alternatively, the reference slot includes a second start slot for the start definite frame. For example, the reference slot includes slot #0 of the radio frame corresponding to Definite Frame Number (DFN) 0.

[0086] In some exemplary embodiments, assume that for the first terminal device 110 and the second terminal device 120, configured with DRX as described above, neither transmission nor reception is permitted during the off-duration 331. Therefore, no missed reserved SCI detections occur during the off-duration 331.

[0087] In some exemplary embodiments, the first and second pools configured for low-power terminal devices are not permitted to be selected by non-low-power terminal devices. For example, if the third terminal device 130 in Figure 1 is a non-low-power terminal device, then neither resource in the first nor the second pool is permitted to be selected by the third terminal device 130.

[0088] In some exemplary embodiments, for the first terminal device 110 and the second terminal device 120 configured with DRX as described above, a resource reservation period shorter than the off-duration 331 is not permitted. Here, the resource reservation period is set from the resource pool's sl-ResourceReservePeriodList-r16.

[0089] In some exemplary embodiments, if the first terminal device 110 determines that there is an overlap period between the off-duration of the DRX cycle and the sensing window, the first terminal device 110 may consider resource selection information received from other terminal devices in order to determine available candidate resources for sidelink transmission. This will be illustrated with reference to Figure 8.

[0090] Figure 8 is an exemplary signaling diagram showing an exemplary process 800 for resource selection according to some other embodiments of the present disclosure. As shown in Figure 8, the process 800 may involve a first terminal device 110 and a third terminal device 130, as shown in Figure 1. The process 800 may include additional operations not shown and / or some operations shown may be omitted, and it should be understood that the scope of the disclosure is not limited in this respect. Furthermore, although presented herein primarily as being performed sequentially, it will be understood that at least some of the operations of the process 800 may be performed simultaneously or in an order different from that shown in Figure 8.

[0091] As shown in Figure 8, the first terminal device 110 determines whether or not there is an overlapping period between the off-duration time of the DRX cycle and the sensing window (810).

[0092] If the first terminal device 110 determines that there is an overlap period, the first terminal device 110 determines the available candidate resources in the resource selection window for the first sidelink transmission based on the resource selection information received from the third terminal device 130 (820).

[0093] In some exemplary embodiments, optionally, if the first terminal device 110 determines that an overlapping period exists, the first terminal device 110 sends a request for information for resource selection to the third terminal device 130 (830). The first terminal device 110 then receives a response to the request from the third terminal device 130 (840). This response includes information for resource selection.

[0094] In some exemplary embodiments, the request includes configuration information relating to the DRX for the first terminal device 110.

[0095] In some exemplary embodiments, if the first terminal device 110 determines that the priority of the data it transmits is higher than the threshold priority, the first terminal device 110 transmits the request.

[0096] In some exemplary embodiments, if the first terminal device 110 determines that the ratio of the first number of at least one candidate sensing occasion during the overlap period to the total number of candidate sensing occasions in the sensing window is higher than a threshold ratio, the first terminal device 110 transmits the request.

[0097] In some exemplary embodiments, optionally, before determining whether an overlapping period exists, the first terminal device 110 receives resource selection information from the third terminal device 120.

[0098] In some exemplary embodiments, the first terminal device 110 performs sensing during a short sensing window after the start of the on-duration in order to determine available candidate resources in the resource selection window for sidelink transmission. This will be illustrated with reference to Figures 9 and 10.

[0099] Figure 9 is an exemplary signaling diagram showing an exemplary process 900 for resource selection according to yet another embodiment of the present disclosure. As shown in Figure 9, the process 900 may involve a first terminal device 110 and a second terminal device 120, as shown in Figure 1. The process 900 may include additional operations not shown and / or some operations shown may be omitted, and it should be understood that the scope of the disclosure is not limited in this respect. Furthermore, although presented herein primarily as being performed sequentially, it will be understood that at least some of the operations of the process 900 may be performed simultaneously or in an order different from that shown in Figure 9.

[0100] As shown in Figure 9, the first terminal device 110 determines whether or not there is an overlapping period between the off-duration time of the DRX cycle and the sensing window (910).

[0101] If the first terminal device 110 determines that an overlapping period exists, the first terminal device 110 receives the SCI and reference signal from the second terminal device 120 within the second sensing window (920). The second sensing window is within the ON duration of the second DRX cycle following the first DRX cycle.

[0102] The first terminal device 110 determines an available candidate resource in the resource selection window for a first sidelink transmission based on at least the first SCI and a reference signal (930). The resource selection window is after the second sensing window and within the ON duration.

[0103] Figure 10 is a schematic diagram illustrating partial sensing and DRX setting according to yet another embodiment of the present disclosure. In the example shown in Figure 10, if the first terminal device 110 determines that there is an overlap period 333 between the off duration 332 of the DRX cycle 330 and the sense window 320 (also referred to as the first sense window 320), the first terminal device 110 receives the SCI and reference signal from the second terminal device 120 on resource 371 in the sense window 370 (also referred to as the second sense window 370). The second sensing window 370 is within the on duration 361 of the DRX cycle 360 ​​following the DRX cycle 330.

[0104] Conversely, if the first terminal device 110 determines, based on the received SCI and reference signal, that resource 372 in the resource selection window 380 is reserved by the second terminal device 120, the first terminal device 110 may determine a different resource from resource 372 in the resource selection window 380 as an available candidate resource. The resource selection window 380 is after the second sensing window 370 and within the on-duration 361.

[0105] In some exemplary embodiments, the length of the second sensing window 370 is associated with at least one of the packet delay budget for the first terminal device 110 or the priority of the data transmitted by the first terminal device 110.

[0106] In some exemplary embodiments, the sensing results of the first terminal device 110 during and after the off-duration 332 may be the same as the sensing results derived during the on-duration 331.

[0107] Figure 11 is a flowchart of an exemplary method 1100 according to some embodiments of the present disclosure. For example, method 1100 can be performed in a first terminal device 110 as shown in Figure 1. Method 1100 may include additional blocks not shown and / or some blocks shown may be omitted, and it should be understood that the scope of the present disclosure is not limited in this respect.

[0108] In block 1110, the first terminal device 110 receives a first SCI and a first reference signal associated with the first SCI from the second terminal device 120 during the on-duration of the DRX cycle. In block 1120, if the first terminal device 110 determines that there is an overlap period between the off-duration of the DRX cycle and the sensing window, the first terminal device 110 determines available candidate resources in the resource selection window for the first sidelink transmission based on at least the first SCI and the first reference signal.

[0109] Additionally, if the first terminal device 110 determines that an overlapping period exists, the first terminal device 110 provides instructions from its physical layer to the protocol layer that at least one candidate sensing occasion during the overlapping period is unavailable. The protocol layer is higher than the physical layer.

[0110] In some exemplary embodiments, the first terminal device 110 determines, based on the first SCI and the first reference signal, a first resource reserved by the second terminal device 120 for a second sidelink transmission. If the first terminal device 110 determines that the first resource is within the off-duration period, the first terminal device 110 receives the second SCI and the second reference signal associated with the second SCI from the second terminal device 120 on the first resource. Furthermore, the first terminal device 110 may determine available candidate resources based on the second SCI and the second reference signal.

[0111] In some exemplary embodiments, the first terminal device 110 may remain active from the start of the off-duration until the end of the first resource, and in that active state, it may receive the second SCI and the second reference signal.

[0112] Alternatively, in some exemplary embodiments, the first terminal device 110 may switch from an inactive state to an active state on the first resource and receive the second SCI and the second reference signal in the active state.

[0113] In some exemplary embodiments, the first terminal device 110 determines a second resource reserved by the second terminal device 120 for a third sidelink transmission, based on the first SCI and a first reference signal. If the first terminal device 110 determines that the second resource is within the off-duration period, the first terminal device 110 may determine a third resource based on the first SCI, the first reference signal, the start of the off-duration period, and the end of the resource selection window. If the first terminal device 110 determines that the third resource is within the resource selection window, the first terminal device 110 may determine a different resource within the resource selection window as an available candidate resource.

[0114] In some exemplary embodiments, the first terminal device 110 may determine at least one fourth resource based on a fifth resource within the off-duration period and at least one preset resource reservation period. If the first terminal device 110 determines that the at least one fourth resource is within the resource selection window, it determines a different resource within the resource selection window as an available candidate resource.

[0115] In some exemplary embodiments, if the first terminal device 110 determines that the priority of the data transmitted by the first terminal device 110 is higher than the threshold priority, the first terminal device 110 determines the at least one fourth resource.

[0116] In some exemplary embodiments, if the first terminal device 110 determines that the channel congestion rate is lower than a threshold rate, the first terminal device 110 determines the at least one fourth resource.

[0117] In some embodiments, if the first terminal device 110 determines that the off duration is less than a threshold duration, the first terminal device 110 determines the at least one fourth resource.

[0118] In some embodiments, if the first terminal device 110 determines that the number of the at least one preset resource reservation period is less than a threshold number, the first terminal device 110 determines the at least one fourth resource.

[0119] In some exemplary embodiments, the first SCI may be transmitted on a fifth resource in a first resource pool configured for the first terminal device 110 and the second terminal device 120. In such exemplary embodiments, the first terminal device 110 may receive the first SCI on a sixth resource in a second resource pool configured for the first terminal device 110 and the second terminal device 120. On-duration and off-duration are configured for the first and second pools, respectively.

[0120] In some exemplary embodiments, the on-duration and off-duration may be set using a first slot index and a second slot index with respect to the reference slot, respectively.

[0121] In some exemplary embodiments, the reference slot may include a first start slot for the serving cell start system frame for the first terminal device 110 and the second terminal device 120. Alternatively, the reference slot may include a second start slot for the start confirmation frame.

[0122] Figure 12 is a flowchart of an exemplary method 1200 according to some embodiments of the present disclosure. For example, method 1200 can be performed in a first terminal device 110 as shown in Figure 1. Method 1200 may include additional blocks not shown and / or some blocks shown may be omitted, and it should be understood that the scope of the present disclosure is not limited in this respect.

[0123] In block 1210, the first terminal device 110 determines whether or not there is an overlapping period between the off-duration time of the DRX cycle and the sensing window.

[0124] If the first terminal device 110 determines in block 1220 that an overlapping period exists, the first terminal device 110 determines available candidate resources in the resource selection window for the first sidelink transmission based on the resource selection information received from the third terminal device 130.

[0125] In some exemplary embodiments, if the first terminal device 110 determines that an overlapping period exists, the first terminal device 110 sends a request for information for resource selection to the third terminal device 130 and receives a response to the request from the third terminal device 130. This response includes information for resource selection.

[0126] In some exemplary embodiments, the request may include configuration information relating to the DRX for the first terminal device 110.

[0127] In some exemplary embodiments, if the first terminal device 110 determines that the priority of the data it transmits is higher than the threshold priority, the first terminal device 110 transmits the request.

[0128] In some exemplary embodiments, if the first terminal device 110 determines that the ratio of the first number of at least one candidate sensing occasion during the overlap period to the total number of candidate sensing occasions in the sensing window is higher than a threshold ratio, the first terminal device 110 transmits the request.

[0129] Additionally, in some exemplary embodiments, before determining whether or not an overlapping period exists, the first terminal device 110 receives resource selection information from the third terminal device 130.

[0130] Figure 13 is a flowchart of an exemplary method 1300 according to some embodiments of the present disclosure. For example, method 1300 can be performed in a first terminal device 110 as shown in Figure 1. Method 1300 may include additional blocks not shown and / or some blocks shown may be omitted, and it should be understood that the scope of the present disclosure is not limited in this respect.

[0131] In block 1310, if the first terminal device 110 determines that there is an overlapping period between the off duration of the first DRX cycle and the first sensing window, the first terminal device 110 receives the SCI and reference signal from the second terminal device 120 within the second sensing window, which is within the on duration of the second DRX cycle following the first DRX cycle.

[0132] In block 1320, the first terminal device 110 determines available candidate resources in the resource selection window for a first sidelink transmission, based at least on the first SCI and a reference signal. The resource selection window is after the second sensing window and within the on-duration.

[0133] In some exemplary embodiments, the length of the second sensing window may be associated with the packet delay budget of the first terminal device 110. Alternatively, the length of the second sensing window may be associated with the priority of the data transmitted by the first terminal device 110.

[0134] Figure 14 is a schematic block diagram of a device 1400 suitable for implementing an embodiment of the present disclosure. Device 1400 can be considered as another exemplary embodiment of the terminal devices 110, 120, or 130 shown in Figure 1. Thus, device 1400 can be implemented in or as part of terminal device 110 or terminal device 120.

[0135] As illustrated, the device 1400 comprises a processor 1410, a memory 1420 coupled to the processor 1410, a suitable transmitter (TX) and receiver (RX) 1440 coupled to the processor 1410, and a communication interface coupled to the TX / RX 1440. The memory 1410 stores at least a portion of the program 1430. The TX / RX 1440 is used for bidirectional communication. The TX / RX 1440 has at least one antenna to facilitate communication, although the access node referred to herein may actually have multiple antennas. The communication interface can represent any interface necessary for communication with other network elements, such as an X2 interface for bidirectional communication between eNBs, an S1 interface for communication between a mobility management entity (MME) / serving gateway (S-GW) and an eNB, an Un interface for communication between an eNB and a relay node (RN), or a Uu interface for communication between an eNB and a terminal device.

[0136] It is assumed that program 1430 includes program instructions that, when executed by the associated processor 1410 as described herein with reference to Figures 1 to 13, enable the device 1400 to operate according to embodiments of the present disclosure. Embodiments of the present can be implemented by computer software executable by the processor 1410 of the device 1400, by hardware, or by a combination of software and hardware. The processor 1410 can be configured to implement various embodiments of the present disclosure. Furthermore, a combination of the processor 1410 and memory 1420 can form a processing means 1450 suitable for implementing various embodiments of the present disclosure.

[0137] Memory 1420 may be of any type suitable for a local technology network and may be implemented using any suitable data storage technology, such as non-temporary 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 1420 is shown in device 1400, several physically different memory modules may be present in device 1400. Processor 1410 may be of any type suitable for a local technology network and may include, as non-limiting examples, one or more of general-purpose computers, dedicated computers, microprocessors, digital signal processors (DSPs), and processors based on multicore processor architectures. Device 1400 may have multiple processors, for example, application-specific integrated circuit chips that are temporally dependent on a clock that synchronizes the main processor.

[0138] Overall, various embodiments of the Disclosure can be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. Some embodiments may be implemented in hardware, while others may be implemented in firmware or software that can be executed by a controller, microprocessor, or other computing device. Various embodiments of the Disclosure are illustrated and described using block diagrams, flowcharts, or any other pictorial representation, but it should be understood that the blocks, devices, systems, techniques, or methods described herein can be implemented, in non-limiting examples, in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or any combination thereof.

[0139] This disclosure also provides at least one computer program product tangibly stored on a non-temporary computer-readable storage medium. The computer program product includes computer-executable instructions, such as instructions contained in a program module, which are executed within a device on a target real or virtual processor to perform any one of the processes or methods described above with reference to Figures 2 to 8 and Figures 11 to 13. Generally, a program module includes routines, programs, libraries, objects, classes, components, data structures, etc., that perform a specific task or implement a specific abstract data type. In various embodiments, the functionality of program modules can be combined or separated from program modules as needed. The machine-executable instructions of a program module can be executed within a local or distributed device. In a distributed device, program modules may be located both in locally readable and remotely readable media.

[0140] Program code for performing the methods of this disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general-purpose computer, a dedicated computer, or other programmable data processing device, and when executed by the processor or controller, the program code may implement the functions / operations specified in the flowcharts and / or block diagrams. The program code may run entirely on a machine, partially on a machine, as an independent software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0141] The program code described above may be implemented on a machine-readable medium, which may be any tangible medium that can contain or store programs used by or associated with an instruction execution system, device, or apparatus. The machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. The machine-readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or apparatus, or any suitable combination of the aforementioned mediums. More specific examples of machine-readable storage media may include electrical connections with one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable optical disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above.

[0142] While the operations have been described in a specific order, it should not be understood that, in order to obtain the desired results, these operations must be performed in the specific order shown, or in a sequential order, or that all of the described operations must be performed. In some cases, multitasking or parallel processing may be advantageous. Similarly, while some specific implementation details are included in the above discussion, these should not be interpreted as limitations on the scope of this disclosure, but rather as descriptions of features that may be specific to a particular embodiment. Some features described in the context of individual embodiments may be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may be implemented separately or in any suitable subcombination in multiple embodiments.

[0143] While this disclosure has been described in language specific to structural features and / or methodological behavior, it should be understood that the disclosure as defined in the attached claims is not necessarily limited to the specific features or behaviors described above. Rather, the specific features and behaviors described above are disclosed as exemplary forms of implementing the claims.

Claims

1. A method performed by a first terminal device, The Physical Sidelink Control Channel reception and Reference Signal Received Power (RSRP) measurement are performed only during sensing occasions within the DRX inactive time slot of a discontinuous reception (DRX) cycle. A method comprising determining the resources for sidelink transmission based on the physical sidelink control channel and the RSRP measurement.

2. The first terminal device, A means for performing reception of the Physical Sidelink Control Channel and measurement of the Reference Signal Received Power (RSRP) only during sensing occasions from slots within the DRX inactive time of a discontinuous reception (DRX) cycle, A first terminal device comprising the physical sidelink control channel and means for determining the resources for sidelink transmission based on the RSRP measurement.

Images