Resource allocation and ue behavior for d2d synchronization signal transmission

Abstract

The present disclosure relates to resource allocation for device-to-device (D2D) synchronization signal transmission and user equipment (UE) behavior. Techniques are disclosed to improve resource allocation for time synchronization and inter-cell D2D discovery between UEs connected to an asynchronous network deployment. In addition, transmission rules are provided for the network, where a discovery resource pool is allocated in a frequency division multiplexing (FDM) manner. There can be an overlap between resources allocated for the discovery resource pool and resources allocated for D2D synchronization signals (D2DSS) in a first subframe of the transmission resource pool. Non-overlapping PRBs in the discovery resource pool can be allocated for WAN transmission or D2D discovery transmission. In the case of FDM allocation of the discovery resource pool, a measurement result such as a reference signal received power or a path loss can be made for the UE. The measurement result can be compared to a threshold to determine whether the UE will transmit a D2DSS.

Description

[0001] This application is a divisional application of Chinese Invention Patent Application No. 201580037165.9 (PCT International Application No. PCT / US2015 / 037170), filed on June 23, 2015, entitled “Resource Allocation and UE Behavior for D2D Synchronization Signal Transmission in Inter-cell D2D Discovery”. Background Technology

[0002] In cellular radio access networks such as the Evolved Universal Mobile Telecommunications System Terrestrial Radio Access Network (E-UTRAN), mobile devices can wirelessly communicate with each other through one or more network nodes such as evolved Node Bs (eNBs). Additionally, proximity-based services that facilitate direct communication between mobile devices are also available in some wireless networks. Attached Figure Description

[0003] The features and advantages of this disclosure will become apparent from the following detailed description taken in conjunction with the accompanying drawings, which illustrate the features of this disclosure by way of example, wherein:

[0004] Figure 1a The example shows a transport resource pool in which the six central PRBs in the first subframe completely overlap with the discovery resource pool;

[0005] Figure 1b The example shows a transport resource pool in which six central PRBs in the first subframe of the transport resource pool partially overlap with the discovery resource pool.

[0006] Figure 2 The example shows a transport resource pool in which the six center PRB202s in the first subframe do not overlap with the discovery resource pool;

[0007] Figure 3 The example shows that, based on the transport resource pool, it was found that the PRB in the first subframe of the transport resource pool is also in one of the six center PRBs.

[0008] Figure 4 The example shows a transport resource pool where the six central PRBs in the first subframe overlap with both the Type-1 discovery resource pool and the Type-2B discovery resource pool.

[0009] Figure 5 Exemplary functionality of a UE, operable according to an example, for performing D2D communication is shown;

[0010] Figure 6 Exemplary functionality of a cellular base station, based on an example, is shown;

[0011] Figure 7A schematic diagram of a wireless device (e.g., UE) based on an example is shown.

[0012] The exemplary embodiments shown will now be described with reference to them and in specific language. However, it should be understood that no limitation is intended to be imposed on the scope herein. Detailed Implementation

[0013] Before disclosing and describing some embodiments, it should be understood that the subject matter for which protection is sought is not limited to the specific structures, processing operations, or materials disclosed herein, but extends to equivalents that would be recognized by one of ordinary skill in the art. It should also be understood that the terminology used herein is for the purpose of describing particular examples only and is not intended to be limiting. The same reference numerals denote the same elements in different figures. The figures provided in the flowcharts and procedures are provided to clearly illustrate operations and do not necessarily indicate a particular order or sequence.

[0014] The following provides a preliminary overview of the technical embodiments, followed by a more detailed description of specific technical embodiments. This preliminary overview is intended to help the reader understand the technology more quickly, and is not intended to identify key or essential features of the technology, nor to limit the scope of the subject matter for which protection is sought.

[0015] For 3GPP Long Term Evolution (LTE) Release 12 (and similarly for future releases), it has been agreed to support certain types of device-to-device (D2D) discovery in network coverage areas. Specifically, inter-cell direct D2D discovery will be supported in both synchronous and asynchronous networks. Because cells in asynchronous networks can use different time and frequency resources, a user equipment (UE) connected to or camped on a first cell and a second UE connected to or camped on an asynchronous second cell need to identify and / or synchronize time and frequency resource pools in order to communicate with each other via D2D signaling. The Radio Access Network-1 (RAN-1) Working Group (WG) has agreed that UEs in asynchronous networks can derive time and frequency synchronization and determine the precise location of resource pools configured in neighboring cells from a combination of the following: (1) neighbor-cell resource-pool configuration signaling forwarded by the serving cell (for UEs in Radio-Resource-Control Connected (RRC_CONNECTED) mode) or by the camping cell (for UEs in Radio-Resource-Control Idle (RRC_IDLE) mode) via System-Message-Block (SIB) signaling; and (2) D2D synchronization signals (D2DSS) sent by UEs in neighboring cells. D2DSS includes a primary D2D synchronization signal (PD2DSS) and a secondary D2D synchronization signal (SD2DSS), where PD2DSS is a Zadoff Chu sequence (i.e., ZC sequence) and SD2DSS is a maximum length sequence (i.e., M sequence). Note that D2DSS, PD2DSS, and SD2DSS are also referred to as Sidelink Synchronization Signal (SSS), Primary Sidelink Synchronization Signal (PSSS), and Secondary Sidelink Synchronization Signal (SSSS), respectively. As used here, the UE transmits a discovery signal at time T = T1 - T2, where T1 is the reception time of the D2DSS transmitted by the D2D synchronization source, which the UE uses as a time reference, and is equal to the DL reception time for the UE's serving or camped cell within network coverage. T2 is an offset that is positive, negative, or zero.

[0016] RAN1 WG defines at least two types of D2D discovery procedures. In Type 1, resources for discovery signal transmissions are allocated in a non-UE-specific manner; resources can be allocated to all UEs or a group of UEs. In Type 2, resources for discovery signal transmissions are allocated in a UE-specific manner. At least two subtypes of Type 2 have been defined: Type 2A (resources are allocated for each specific transmission instance of the discovery signal) and Type 2B (resources are semi-permanently allocated for discovery signal transmissions). Note that the transmission of the Physical Sidelink Discovery Channel (PSDCH) in the 3GPP specification also references discovery signal or message transmissions.

[0017] Regarding Type 1 discovery, in Frequency Division Multiplexing (FDD) mode (a bidirectional communication mode where transmission and reception occur at the same time on different carrier frequencies), RAN1 WG has agreed that UEs in RRC_CONNECTED mode should send discovery signals based on the downlink (DL) reference time (T2 = 0). In Time Division Multiplexing (TDD) mode (a bidirectional communication mode where transmission in each direction occurs on the same carrier frequency in different time slots), RAN1 WG has agreed that UEs in RRC_CONNECTED and RRC_IDLE modes should send discovery signals based on the reference time T2 = 624Ts.

[0018] Regarding Type 2B discovery, for a UE in RRC_Connected mode that sends a Type 2B discovery signal, if a UE in RRC_Idle mode cannot send a Type 2B discovery signal, the value of T2 can be, for example, between the following two values: T2 = Active Timing Advance (TA) value for FDD mode and T2 = 624Ts + TA for TDD mode; T2 = 0 for FDD mode and 624Ts for TDD mode. On the other hand, if a UE in RRC_Idle mode can send a Type 2B discovery signal, the value of T2 can be, for example, T2 = 0 for FDD mode and 624Ts for TDD mode.

[0019] Furthermore, the RAN1 WG has agreed that if the network supports both D2D discovery and D2D communication, the D2DSS-transmission configuration used for both will be identical. For Type 1 discovery, UEs in a cell can transmit PD2DSS and SD2DSS during the first subframe of the transport resource pool in the discovery period. If the transport resource pool is configured by the evolved Node B (eNB) using a System Information Block (SIB) broadcast, the PD2DSS and SD2DSS sequences for a given transmission can also be configured using SIB broadcast, and the same PD2DSS and SD2DSS sequences are used for D2D communication. If the transport resource pool is not configured using SIB broadcast, the PD2DSS and SD2DSS sequences can be configured using dedicated Radio-Resource-Control (RRC) signaling. For Type 2B discovery, the eNB can instruct one or more UEs to transmit PD2DSS and SD2DSS sequences.

[0020] The RAN1 WG has agreed that the PD2DSS and SD2DSS used for discovery transmissions in the first subframe of the transport resource pool occupy the six central physical resource blocks (PRBs) of the uplink (UL) system bandwidth (BW). These six central PRBs may overlap with the discovery resource pool, which comprises a subset of the resources in the transport resource pool. For systems with larger system bandwidths (e.g., 50 PRBs for a system with 10 MHz bandwidth or 100 PRBs for a system with 20 MHz bandwidth), there is currently no agreed-upon method for using the remaining PRBs in the first subframe of the discovery resource pool (i.e., PRBs other than the six central PRBs in the first subframe of the discovery resource pool).

[0021] On the one hand, non-central PRBs can be left idle; this ensures that there is no interference from in-band transmission (IBE) caused by transmissions in remaining PRBs that would otherwise affect D2DSS transmissions received in the central PRB. However, this approach leads to a waste of available spectrum at the system level. Therefore, it is necessary to specify how any remaining PRBs in the first subframe of the discovery resource pool will be used to avoid wasting available spectrum resources.

[0022] Additional rules for D2DSS transmissions also need to be defined when multiple discovery resource pools are allocated in frequency division multiplexing (FDM) mode, such as rules for identifying the reference time to be used and rules for determining which UE will transmit a given D2DSS.

[0023] The examples in this disclosure provide rules for resource allocation in the first subframe for discovering the resource pool, where the discovery resource pool is a subset of the transport resource pool, and the six PRBs at the center of the transport resource pool are used for D2DSS. Additional examples provide timing options for D2DSS transmissions between UEs communicating with asynchronous network deployments. For example, if a first UE is in a first cell and a second UE is in a second cell, and the second cell uses a time asynchronous with the first cell, then these two cells are associated with an asynchronous network deployment. The first UE and the second UE can establish D2D communication with each other using D2DSS.

[0024] The additional examples provide rules for D2DSS transmissions when Type 1 and Type 2B discovery resource pools are allocated in an FDM manner. Although some examples related to inter-cell D2D discovery support have been illustrated, the concepts elucidated in the rules for resource allocation in the first subframe for discovery resource pools can also be used to support inter-cell D2D communication by associating D2DSS transmissions with a Scheduled Assignment (SA) resource pool, which is also referred to as the Physical Sidelink Control Channel (PSCCH) and configured for D2D communication.

[0025] In some of the examples below, the discovery resource pool is shown as a contiguous block of time and frequency resources. The frequency range of the discovery resource pool can extend from a value specified in a first parameter (start PRB) to a value in a second parameter (end PRB), where the start PRB and end PRB are transmitted to the UE via SIB signaling. However, a single discovery resource pool can also include two or more separate blocks from a transport resource pool. When a discovery resource pool includes more than one separate resource block, additional parameters can be added to the SIB signaling to transmit start and end frequency values ​​defining the additional resource blocks. For example, if there are two separate resource blocks defining a single discovery resource pool, the start PRB and end PRB can be used to define the frequency range of the first block, while two additional parameters (e.g., start PRB2 and end PRB2) can be used to define the frequency range of the second block.

[0026] In some examples of the following examples (e.g., the example described in Option 3), it is assumed that the configuration of the discovery resource pool in the first subframe (i.e., subframe #0) of the transport resource pool is the same as the configuration of the discovery resource pool in subsequent subframes (i.e., subframes #1 to #N-1, where the transport resource pool spans N subframes). However, it is also possible to use a first configuration of the discovery resource pool in the first subframe and a second configuration in subsequent subframes with the same transport resource pool. For example, if the transport resource pool is configured such that the six center PRBs in the first subframe are used for D2DSS, then the configuration of the discovery resource pool in the first subframe can be considered to include only those six center PRBs. For subsequent subframes, the configuration of the discovery resource pool is considered to include the frequency range defined by the start PRB and end PRB (and, where available, start PRB2 and end PRB2, etc.). If the transport resource pool is not configured such that the six center PRBs in the first subframe are used for D2DSS, then the same configuration (e.g., the configuration where the frequency range is defined by the start PRB and end PRB) can be applied to all subframes of the transport resource pool. The concept of having different configurations for the first subframe and subsequent subframes can be used to, for example, help implement the methods of options 1 and 2 (described below).

[0027] When one or more D2D discovery resource pools are used and time-division multiplexing (TDM) is allocated at the system level, the resource allocation for the first subframe of the D2D discovery resource pool is as follows: Option 1

[0028] In Option 1, the remaining PRBs in the first subframe of the resource pool (i.e., the PRBs in the transport resource pool other than the six center PRBs used for D2DSS) can be left idle. As mentioned above, this option results in a loss of system-level spectral efficiency in the UL direction. However, it also avoids potential interference to D2DSS transmissions received in the center PRBs caused by in-band transmission (IBE) due to transmission in the remaining PRBs.

[0029] When one or more D2D discovery resource pools are used and time-division multiplexing (TDM) is allocated at the system level, the resource allocation for the first subframe of the D2D discovery resource pool is as follows: Option 2

[0030] In Option 2, the remaining PRBs in the first subframe of the resource pool (i.e., PRBs in the transport resource pool other than the six central PRBs used for D2DSS) can be allocated for normal wide area network (WAN) transport. In this case, the eNB can schedule regular Physical Uplink Shared Channel (PUSCH) transport for normal UEs. This method has minimal impact on WAN transport compared to Option 1. Additionally, the eNB can reduce interference with D2DSS transport caused by IBE by applying appropriate power control when scheduling UEs close to the eNB.

[0031] When one or more D2D discovery resource pools are used and time-division multiplexing (TDM) is allocated at the system level, the resource allocation for the first subframe of the D2D discovery resource pool is as follows: Option 3

[0032] In Option 3, the remaining PRBs in the first subframe of the discovery resource pool (i.e., PRBs in the transmission resource pool other than the six center PRBs used for D2DSS) can be allocated for discovery signal transmission. To reduce interference to D2DSS transmission caused by IBE, a separate set of parameters (e.g., P0 and alpha parameters) for open-loop power control of the D2D discovery signal can be used to limit the transmission power when the remaining PRBs are used for discovery signal transmission.

[0033] Figure 1a An exemplary transport resource pool 100a is shown, wherein the six central PRBs 102a in the first subframe 106a of transport resource pool 100a completely overlap with the discovery resource pool 104a. Discovery resource pool 104a can be type 1 or type 2B. WAN resource 108a and Physical Uplink Control Channel (PUCCH) resource 110a are also shown in transport resource pool 100a. The horizontal axis of transport resource pool 100a represents time, and the vertical axis represents frequency. The remaining PRBs 112a can be used for discovery transmissions. When configuring discovery resource pool 104a, the eNB may need to specify that the discovery resource pool includes the six central PRBs 102a. Additionally, for the remaining PRBs 112a, the UE can be configured not to perform duplicate transmissions for D2D discovery.

[0034] Figure 1bAn exemplary transport resource pool 100b is shown, wherein the six central PRBs 102b in the first subframe 106b of transport resource pool 100b partially overlap with the discovery resource pool 104b. Discovery resource pool 104b can be type 1 or type 2B. WAN resource 108b and Physical Uplink Control Channel (PUCCH) resource 110b are also shown in transport resource pool 100b. The horizontal axis of transport resource pool 100b represents time, and the vertical axis represents frequency. The remaining PRBs 112b can be used for discovery transmissions. When configuring discovery resource pool 104b, the eNB may need to specify that the discovery resource pool includes the six central PRBs 102b. Additionally, for the remaining PRBs 112b, the UE can be configured not to perform duplicate transmissions for D2D discovery.

[0035] Figure 2 An exemplary transport resource pool 200 is shown, wherein the six central PRBs 202 in the first subframe 206 of transport resource pool 200 do not overlap with the discovery resource pool 204. Discovery resource pool 204 can be type 1 or type 2B. WAN resource 208 and Physical Uplink Control Channel (PUCCH) resource 210 are also shown in transport resource pool 200. The horizontal axis of transport resource pool 200 represents time, and the vertical axis represents frequency. Because discovery resource pool 204 and the six central PRBs 202 do not overlap, the six central PRBs can be used for D2DSS, and all resources in discovery resource pool 204 in the first subframe 206 can be allocated for discovery transport.

[0036] Figure 3 An exemplary transport resource pool 300 is shown, wherein only the PRBs in the first subframe 306 of transport resource pool 300, located in discovery resource pool 304, are also in the six central PRBs 302. Discovery resource pool 304 can be type 1 or type 2B. WAN resource 308 and Physical Uplink Control Channel (PUCCH) resource 310 are also shown in transport resource pool 300. The horizontal axis of transport resource pool 300 represents time, and the vertical axis represents frequency. In this case, D2DSS can still be transmitted in the six central PRBs 302. PRBs in other subframes of discovery resource pool 304 besides the first subframe 306 can be allocated for D2D discovery transmission.

[0037] Figure 4An exemplary transport resource pool 400 is shown, wherein the six central PRBs 402 in the first subframe 406 of the transport resource pool 400 overlap with both the Type 1 discovery resource pool 404 and the Type 2B discovery resource pool 405. WAN resources 408 and Physical Uplink Control Channel (PUCCH) resources 410 are also shown in the transport resource pool 400. The horizontal axis of the transport resource pool 400 represents time, and the vertical axis represents frequency. In this case, the remaining PRBs 411 in the first subframe 406 of the transport resource pool 400 from the Type 1 discovery resource pool 404 can be allocated for Type 1 D2D discovery transport. Additionally, the remaining PRBs 412 in the first subframe 406 of the transport resource pool 405 from the Type 2B discovery resource pool 405 can be allocated for Type 2B D2D discovery transport.

[0038] When multiple discovery resource pools, which can be either type 1 or type 2B discovery resource pools, are allocated in an FDM manner, it is similar to Figures 1a to 4 The resource mechanisms shown can be used.

[0039] When Type 1 and Type 2B discovery resource pools are allocated in TDM mode, the D2DSS transfer time used for D2D discovery in asynchronous deployments.

[0040] When the six center PRBs in the first subframe of the transport resource pool overlap with a Type 1 discovery resource pool allocated in TDM mode, the D2DSS transmitted in the six center PRBs can simply follow the transmission time used for Type 1 discovery (e.g., by using DL reference time). When the six center PRBs in the first subframe of the transport resource pool overlap with a Type 2B discovery resource pool allocated in TDM mode, the D2DSS transmitted in the six center PRBs can follow the transmission time used for Type 2B discovery, or can be fixed to follow either DL or UL reference time. For UEs with Active Timing Advance (TA) configuration, UL reference time = DL reference time + TA.

[0041] When Type 1 and Type 2B discovery resource pools are allocated in FDM mode, the D2DSS transfer time used for D2D discovery in asynchronous deployments.

[0042] When the six central PRBs in the first subframe of the transmission resource pool overlap with a Type 1 or Type 2B discovery resource pool allocated in FDM mode, there are at least two different time options available. These options are partly inspired by the observation that when multiple UEs attempt to transmit D2DSS in a single-frequency network (SFN) manner, following a single reference time for all D2DSS transmissions within the cell improves detection performance.

[0043] In Option 1, D2DSS can be transmitted based on DL reference time, regardless of the transmission time used for discovery signal transmission (e.g., regardless of whether the discovery resource pool is Type 2B and whether UL or DL ​​reference time is used). Accordingly, if a Type 2B transmitter UE is instructed to transmit D2DSS (either explicitly instructed by the serving eNB or according to some predefined criteria), and if the Type 2B transmitter UE knows of a Type 1 discovery resource pool multiplexed with a Type 2B discovery resource pool via FDM, then it transmits D2DSS according to DL time. Alternatively, the serving eNB can explicitly transmit the time to be used for D2DSS transmission as part of the resource pool configuration (e.g., by indicating whether TA will be used for D2DSS transmission).

[0044] In option 2, a D2D UE with active TA configuration (e.g., a UE with active TA configuration and in RRC_CONNECTED mode) can transmit D2DSS based on UL reference time. This option is reasonable if the UE is also configured to transmit Type 2B discovery signal transmissions using UL reference time.

[0045] To provide configurability between Option 1 and Option 2, it can be specified that a UE in RRC_IDLE mode using a Type 1 discovery resource pool will follow the DL base time for D2DSS transmission. It can also be specified that a UE with an active TA in RRC_CONNECTED mode will follow the transmission time associated with Type 2B discovery signal transmission for D2DSS transmission, unless the UE is explicitly configured by the serving eNB to use the DL base time for D2DSS transmission, or configured to infer that the DL base time should be used for D2DSS transmission based on the presence of FDM multiplexing of Type 1 and Type 2B discovery resource pools.

[0046] When Type 1 and Type 2B discover resource pools are allocated in FDM mode, the D2DSS transport rules that can be used are...

[0047] When Type 1 and Type 2B discovery resource pools are allocated in FDM mode, it is necessary to determine which UE will send D2DSS rules. The following examples illustrate several different types of rules that can be applied. The rules in the following examples can be used individually or in combination.

[0048] In one example, a rule could be adopted that causes only UEs configured by the serving eNB to send D2DSS signals. The serving eNB can instruct the UE to send D2DSS signals via RRC signaling. The UE instructed to send D2DSS signals can be an RRC_CONNECTED UE participating in D2D discovery. Alternatively, the UE instructed to send D2DSS signals can be an RRC_IDLE UE that can be paged by the eNB of the serving cell.

[0049] In another example, a UE in RRC_CONNECTED or RRC_IDLE mode can be configured to autonomously transmit D2DSS signals based on a predetermined criterion, without requiring any explicit instruction from the eNB. The UE can measure the Reference Received Power (RSRP) from the serving eNB (and possibly from other eNBs) and calculate the path loss. The path loss and / or RSRP can be compared with thresholds configured by the eNB to determine whether the pre-configured criterion is met. When the pre-configured criterion is met, the UE can transmit D2DSS. Optionally, the UE's decision to transmit D2DSS can be overturned by instruction from the serving / campored eNB.

[0050] In another example, the UE can report path loss measurements (or other relevant measurements) to the eNB. The eNB can use the measurements received from the UE to determine whether the UE (and possibly other UEs) should send a D2DSS. The eNB can then, if available, instruct the UE to send a D2DSS using UE-specific signaling. The UE can be in RRC_CONNECTED mode and participate in D2D discovery. The UE can also be in RRC_IDLE mode and can be paged by the eNB of the camped cell to report path loss measurements (or relevant measurements). Alternatively, if the UE is in RRC_IDLE mode, it can also be paged by the eNB of the camped cell to report metrics used in mobility management procedures; the eNB can also use these metrics to determine a group of UEs that will be instructed to send a D2DSS.

[0051] If the specified UE behavior differs when the Type 1 and Type 2B discovery resource pools are multiplexed via FDM compared to when they are multiplexed via TDM, the eNB can transmit this difference via explicit eNB signaling as part of the transport resource pool configuration. Alternatively, the UE can be configured to infer this difference based on the presence of FDM between the Type 1 and Type 2B discovery resource pools.

[0052] Figure 5An exemplary function 500 of a device operable to perform D2D communication for a UE is illustrated. This function may be implemented as a method, or it may be executed on a machine as instructions, wherein these instructions are included on at least one non-transient computer-readable storage medium. In block 510, circuitry at the UE may receive device-to-device synchronization signal (D2DSS) configuration information and device-to-device synchronization signal (D2DSS) transmission timing information for supporting inter-cell D2D discovery in asynchronous deployments. The circuitry at the UE may include, for example, one or more processors (e.g., a baseband processor and an application processor), one or more transceivers communicating with one or more baseband processors, and one or more antennas. In some embodiments, the circuitry at the UE may also include separate modules such as a transceiver module and a processing module. The D2DSS configuration information and D2DSS transmission timing information may be received wirelessly via antennas. These antennas may be part of or communicate with the transceiver module at the UE. In some embodiments, the transceiver module may provide the D2DSS configuration information and D2DSS transmission timing information to one or more processors at the UE.

[0053] In block 520, a circuit at the UE including one or more processors (e.g., a processing module) can identify multiple Physical Resource Blocks (PRBs) allocated for D2DSS transmission in the first subframe of the transport resource pool based on D2DSS configuration information. These multiple PRBs may include the six central PRBs in the first subframe of the transport resource pool. The transport resource pool may also include a D2D discovery resource pool. Resources in the D2D discovery resource pool can be allocated using Time Division Multiplexing (TDM) or Frequency Division Multiplexing (FDM). Resources in the D2D discovery resource pool can be allocated based on a non-UE-specific method (Type 1) or semi-permanently allocated based on a UE-specific method (Type 2B).

[0054] Multiple PRBs can overlap with a D2D discovery resource pool. A PRB in the first subframe of a D2D discovery resource pool that is not included in the multiple PRBs allocated for D2DSS transport can be allocated for WAN transport or D2D discovery transport.

[0055] In block 530, the circuitry at the UE (e.g., one or more transceivers coupled to one or more baseband processors) can receive or transmit D2D synchronization signals (D2DSS) based on D2DSS configuration information (e.g., via antenna and transceiver module). When resources in the D2D discovery resource pool are allocated in TDM mode, the circuitry at the UE can transmit D2D synchronization signals (D2DSS) based on downlink (DL) reference time or type 2B transmission time (e.g., via transceiver module). When resources in the D2D discovery resource pool are allocated in FDM mode, the circuitry at the UE can transmit D2DSS based on downlink (DL) reference time or uplink (UL) reference time (e.g., via transceiver module).

[0056] Additionally, if resources in the D2D discovery resource pool are allocated in FDM mode, the circuitry at the UE can calculate measurements such as Reference Signal Received Power (RSRP) or path loss (e.g., using a processing module including one or more processors) and determine whether the D2DSS should be transmitted by the UE based on these measurements. The circuitry at the UE can then make a determination on whether the D2DSS should be transmitted based on a comparison between the measurement results and a threshold. Alternatively, the circuitry at the UE can also transmit the measurement results to the eNB (e.g., via a transceiver module). The eNB can then determine whether the UE will transmit the D2DSS based on the measurement results and send a reversal command to the UE including this determination. When both methods for determining whether the UE should transmit the D2DSS are used, the reversal command from the eNB can replace the determination made by the circuitry at the UE.

[0057] Figure 6An exemplary function 600 of a cellular base station is illustrated. This function can be implemented as a method, or it can be executed as instructions on a machine, wherein these instructions are included on at least one non-transient computer-readable storage medium. In 610, circuitry at the cellular base station (e.g., a processing module including one or more processors) can allocate multiple physical resource blocks (PRBs) in a first subframe of a transport resource pool for device-to-device synchronization signal (D2DSS) transmission. In 620, circuitry at the cellular base station (e.g., a processing module including one or more processors) can allocate a D2D discovery resource pool within the transport resource pool. In 630, circuitry at the cellular base station (e.g., a processing module including one or more processors) can receive measurement results transmitted from at least one UE in a cell (e.g., a cell served by the cellular base station). In 640, circuitry at the cellular base station (e.g., a processing module including one or more processors) can determine, based on the measurement results, whether to signal at least one UE to transmit a D2D synchronization signal (D2DSS) (i.e., make a determination on whether to signal at least one UE to transmit D2DSS). The measurement results may include a reference signal received power (RSRP) or a path loss order. In some examples, the circuitry can determine whether to signal at least one UE to send D2DSS based on a comparison between the measurement result and a threshold. At 650, circuitry at the cellular base station (e.g., a transceiver module including a transceiver communicating with one or more antennas) can send a transmission command to at least one UE indicating the determination.

[0058] Figure 7 Example illustrations are provided for wireless devices such as User Equipment (UE), Mobile Station (MS), Mobile Wireless Device, Mobile Communication Device, Tablet PC, Mobile Phone, or other types of wireless devices. The wireless device may include one or more antennas configured to communicate with nodes, macro nodes, low-power nodes (LPNs), or transmission stations, such as base stations (BS), evolved Node Bs (eNBs), baseband units (BBUs), remote radio heads (RRHs), remote radio equipment (RREs), relay stations (RSs), radio equipment (REs), or other types of wireless wide area network (WWAN) access points. The wireless device may be configured to communicate using at least one wireless communication standard, including 3GPP LTE, WiMAX, High-Speed ​​Packet Access (HSPA), Bluetooth, and WiFi. The wireless device may communicate using separate antennas for each wireless communication standard or a shared antenna for multiple wireless communication standards. The wireless device may communicate in a wireless local area network (WLAN), a wireless personal area network (WPAN), and / or a WWAN.

[0059] Figure 7It also provides illustrations of a microphone and one or more speakers that can be used for audio input and audio output from the wireless device. The display screen can be a liquid crystal display (LCD) screen, or other types of displays such as organic light-emitting diode (OLED) displays. The display screen can be configured as a touchscreen. The touchscreen can use capacitive, resistive, or other types of touchscreen technology. The application processor and graphics processor can be coupled to the internal memory to provide processing and display capabilities. Non-volatile memory ports can also be used to provide data input / output options to the user. Non-volatile memory ports can also be used to expand the memory capacity of the wireless device. The keyboard can be integrated with the wireless device or wirelessly connected to it to provide additional user input. A virtual keyboard can also be provided using a touchscreen.

[0060] Various technologies and certain aspects or parts thereof may take the form of program code (i.e., instructions) embedded in a tangible medium, such as a floppy disk, CD-ROM, hard drive, non-transient computer-readable storage medium, or any other machine-readable storage medium, wherein when the program code is loaded into a machine such as a computer and executed by the machine, the machine becomes a means for implementing the various technologies. Circuitry may include hardware, firmware, program code, executable code, computer instructions, and / or software. Non-transient computer-readable storage media may be computer-readable storage media that does not include signals. In the case of program code execution on a programmable computer, a computing device may include a processor, a processor-readable storage medium (including volatile and non-volatile memory and / or storage elements), at least one input device, and at least one output device. Volatile and non-volatile memory and / or storage elements may be RAM, EPROM, flash memory drive, optical disk drive, hard disk drive, solid-state drive, or other media for storing electronic data. Nodes and wireless devices may also include transceiver modules, counter modules, processing modules, and / or clock modules or timer modules. One or more programs that can implement or utilize the various technologies described herein may use application programming interfaces (APIs), reusable controls, etc. These programs may be implemented in high-level or object-oriented programming languages ​​to communicate with the computer system. However, when needed, one or more programs may be implemented in assembly or machine language. In any case, the language may be a compiled or interpreted language and may be combined with hardware implementations.

[0061] As used herein, the word “or” indicates inclusive disjunction. For example, the phrase “A or B” as used herein represents inclusive disjunction of exemplary conditions A and B. Therefore, “A or B” is false only if condition A is false and condition B is false. “A or B” is also true when condition A is true and condition B is also true. “A or B” is true when condition A is true and condition B is false. “A or B” is true when condition B is true and condition A is false. In other words, the term “or” as used herein should not be understood as exclusive disjunction. The term “exclusive OR” is used when exclusive disjunction is desired.

[0062] As used herein, the term "processor" can include general-purpose processors, special-purpose processors such as VLSL, FPGA, and other types of special-purpose processors, as well as baseband processors used in transceivers to transmit, receive, and process wireless communications.

[0063] It should be understood that many of the functional units described in this specification have been labeled as modules to more specifically emphasize their implementation independence. For example, a module can be implemented as a hardware circuit that includes custom VLSL circuitry or gate arrays, logic chips, transistors, or other discrete components from off-the-shelf semiconductors. Modules can also be implemented in programmable hardware devices such as field-programmable gate arrays, programmable array logic, programmable logic devices, etc.

[0064] Modules can also be implemented in software executed by various types of processors. The executable code identifying a module can include, for example, one or more physical or logical blocks of computer instructions, which can be organized, for example, into objects, procedures, or functions. However, the executable files identifying the module do not need to be physically located together, but can include different instructions stored in different locations, which, when logically grouped together, constitute the module and achieve the aforementioned purpose of the module.

[0065] In practice, an executable code module can be a single instruction or many instructions, and can even be distributed across multiple different code segments in different programs on several memory devices. Similarly, operational data can be identified and represented within the module, and can be embodied in any suitable form and organized in any suitable type of data structure. Operational data can be collected in a single data set or distributed across different locations (including different storage devices), and can exist at least partially as electronic signals on a system or network. Modules can be passive or active modules and include agents operable to perform desired functions.

[0066] As used herein, the term "processor" can include general-purpose processors, special-purpose processors such as VLSI, FPGA, and other types of special-purpose processors, as well as baseband processors used in transceivers to transmit, receive, and process wireless communications.

[0067] Throughout the specification, the phrase "an example" means that a particular feature, structure, or characteristic described in connection with the example is included in at least one embodiment of this disclosure. Therefore, the phrase "in an example" appearing in multiple places throughout the specification does not necessarily refer to the same embodiment.

[0068] As used herein, for convenience, multiple items, structural elements, composite elements, and / or materials may be presented in a general list. However, these lists should be understood as each element in the list being identified as a separate and unique element. Therefore, without indication to the contrary, one element should not be construed as a de facto equivalent of another element in such a list simply because some elements in such lists appear in the same group. Furthermore, various embodiments and examples of this disclosure may be referenced herein along with alternatives to their various components. It should be understood that these embodiments, examples, and alternatives should not be construed as de facto equivalents of each other, but should be considered as independent and autonomous representations of this disclosure.

[0069] Furthermore, the features, structures, or characteristics described herein can be combined in any way in one or more embodiments. In the following description, various specific details, such as layouts, distances, network examples, etc., are provided to provide a thorough understanding of embodiments of this disclosure. However, those skilled in the art will recognize that embodiments of this disclosure can be implemented without one or more of these specific details, or implemented using other methods, components, layouts, etc. In other instances, well-known structures, materials, or operations have not been shown or described in detail to avoid obscuring various aspects of this disclosure.

[0070] While the foregoing examples illustrate the principles of this disclosure in one or more specific applications, those skilled in the art will understand that various modifications can be made to the use, details, and form of the embodiments without departing from the principles and concepts of this disclosure and without inventiveness. Therefore, this disclosure is not intended to be limited beyond the appended claims.

Claims

1. An apparatus for a user equipment (UE) operable to perform inter-cell device-to-device (D2D) discovery in a wireless network, the apparatus comprising: Memory, used to store instructions; as well as One or more processors are configured to execute the instructions to: The UE receives configuration information from the Evolved Universal Mobile Telecommunications System Terrestrial Radio Access Network (E-UTRAN), wherein the configuration information is used for inter-cell D2D discovery at the UE and includes information for configuring multiple discovery resource pools; and When the UE sends a secondary link synchronization signal discovery message by a radio-resource-control (RRC) signaling instruction, the secondary link synchronization signal discovery message is sent to the second UE on resources in multiple discovery resource pools based on the configuration information. The multiple discovery resource pools are allocated in a frequency division multiplexing (FDM) manner.

2. The apparatus of claim 1, wherein, The one or more processors are also configured to process system information blocks (SIBs) received from the E-UTRAN.

3. The apparatus of claim 1, further comprising: The transceiver is configured to process the configuration information received from the E-UTRAN via RRC signaling or via broadcast.

4. The apparatus of claim 1, wherein, The allocated resources correspond to the first subframe of the transmission resource pool, which is allocated for secondary link synchronization signal (SLSS) transmission based on the configuration information.

5. The apparatus of claim 1, wherein, The one or more processors are also configured to encode SLSS discovery messages to be sent to the second UE based on downlink reference time.

6. The apparatus of claim 1, wherein, The UE includes an antenna, a touch-sensitive display, a speaker, a microphone, a graphics processor, an application processor, internal memory, a non-volatile memory port, a transceiver, or a combination thereof.

7. An eNodeB apparatus operable to assist a user equipment (UE) in performing inter-cell device-to-device (D2D) discovery in a wireless network, the apparatus comprising: Memory, used to store instructions; as well as One or more processors are configured to execute the instructions to: Configuration information is sent at the eNodeB, wherein the configuration information is used for inter-cell D2D discovery at the UE. The configuration information includes information for configuring multiple discovery resource pools, wherein the configuration information enables the UE to perform inter-cell D2D discovery on resources in multiple discovery resource pools when the UE is sent a secondary link synchronization signal discovery message by a radio-resource-control (RRC) signaling instruction. The multiple discovery resource pools are allocated in a frequency division multiplexing (FDM) manner.

8. The apparatus of claim 7, wherein, The one or more processors are also configured to process system information blocks (SIBs) to be sent to the UE.

9. The apparatus of claim 7, wherein, The one or more processors are also configured to process the configuration information for transmission to the UE via RRC signaling.

10. The apparatus of claim 7, wherein, in, The one or more processors are also configured to process the configuration information for transmission to the UE via broadcast.

11. A machine-readable storage medium storing instructions thereon for performing inter-cell device-to-device (D2D) discovery at a user equipment (UE) in a wireless network, the instructions causing the UE to perform the following operations when executed by one or more processors: The UE receives configuration information from the Evolved Universal Mobile Telecommunications System Terrestrial Radio Access Network (E-UTRAN), wherein the configuration information is used for inter-cell D2D discovery at the UE, and the configuration information includes information for configuring multiple discovery resource pools; and When the UE sends a secondary link synchronization signal discovery message by a radio-resource-control (RRC) signaling instruction, the secondary link synchronization signal discovery message is sent to the second UE on resources in multiple discovery resource pools based on the configuration information. The multiple discovery resource pools are allocated in a frequency division multiplexing (FDM) manner.

12. The machine-readable storage medium of claim 11, further comprising instructions that, when executed by the one or more processors, cause the UE to perform the following operation: process a system information block (SIB) received from the E-UTRAN.

13. The machine-readable storage medium of claim 11, further comprising instructions that, when executed by the one or more processors, cause the UE to perform the following operations: process the configuration information received from the E-UTRAN via dedicated signaling or via broadcast.

14. The machine-readable storage medium of claim 11, wherein, The allocated resource is the available subframe closest to the first subframe in the transmission resource pool, which is allocated for secondary link synchronization signal (SLSS) transmission based on the configuration information.

15. The machine-readable storage medium of claim 11, further comprising instructions that, when executed by the one or more processors, cause the UE to perform the following operation: encode an SLSS discovery message to be transmitted to the second UE based on downlink reference time.

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