HK40056604A - A method of processing a received channel signal in a device to device communications link using multiple reference symbols - Google Patents

Description

Method for processing a received channel signal in a device-to-device communication link using a plurality of reference symbols

Technical Field

The present invention relates generally TO device-TO-device wireless communications, and more particularly, but not exclusively, TO decoding signals of channels such as a physical side link shared channel (psch) and a physical side link control channel (PSCCH) using estimation and compensation for Timing Offset (TO) and DMRS identification and checking multiple PSCCH (DMRS) symbols. The invention is particularly suitable for the side link in the vehicle wireless communication technology (V2X) communication system.

Background

The sidelink is a feature of the third generation partnership project (3GPP) Long Term Evolution (LTE) and was first introduced in 3GPP Release 12 to achieve device-to-device (D2D) communication within a conventional cellular-based LTE radio access network. Sidelink has been enriched in 3GPP release 14 with various features. D2D applies to the use cases of public safety and commercial communications, and more recently to the V2X case in 3GPP Release 14.

Intelligent transportation systems provide a framework for road users and traffic managers to share information, where V2X defines the exchange of information between vehicles and other types of stations/devices (e.g., roadside units, infrastructure, pedestrians, or other vehicles). In the V2X physical layer, LTE-V2X uses side link channels designed based on LTE uplink waveforms. Two side link modes dedicated to V2X are introduced in 3GPP Release 14: mode 3 and mode 4 support direct vehicle communication, but differ in how the resources of the station are allocated. In mode 3, the vehicle is within coverage of the cellular network and the resources of the station are selected, allocated and reserved by the eNodeB. In contrast, mode 4 is designed to work without being under coverage of the cellular network: the resources are selected autonomously by the station/device without the involvement of the eNodeB even if present.

Side link waveform design is similar to LTE uplink, which was developed earlier, reusing the same principles for subframe structure. LTE-V2X is a synchronous network in which all users have the same substantially synchronous time reference (typically obtained from Global Navigation Satellite Systems (GNSS)). Time is divided into subframes. Each LTE subframe has a length of 1ms and contains 14 OFDM symbols. One LTE-V2X subframe includes 4 DMRS symbols and 9 data symbols conveying the user payload. The last symbol is not sent and serves as time protection to allow the transmitter to revert to the receiver state before the next subframe. The first data symbol may not be used by the receiver because it may be used for calibration purposes for Automatic Gain Control (AGC).

In frequency, the LTE-V2X channel bandwidth is divided into a given number of sub-channels. Each subchannel includes a plurality of Resource Blocks (RBs) having 12 subcarriers. Two main physical channels are used in LTE-V2X: the psch (referred to as a Transport Block (TB)) used to transmit data packets and the physical side link control channel (PSCCH) used to transmit associated control information, referred to as side link control information (SCI). The PSCCH SCI and its associated psch TB may be transmitted in the same subframe or in different subframes.

The PSCCH always occupies two RBs. Each of multiple DMRS carriers of PSCCH has a cycleShifting (n)_cs) Sequence of 24-bit sampled complex values of the parameter, cyclic shift (n)_cs) The parameters define how "fast" the DMRS sequence rotates in the complex plane. PSCCH DMRS is a cyclic shift (n) from Zadoff-Chu sequence in combination with_cs) Derived constant modulus sign. Cyclic shift (n)_cs) The values are chosen randomly by the transmitter, so the receiver does not know which cyclic shift (n)_cs) The value has already been selected. With different cyclic shifts (n)_cs) DMRSs of values are mutually orthogonal. In V2X, cyclic shift (n)_cs) The value may be 0,3,6 or 9. Any offset in the timing of the received PSCCH violates the orthogonality condition.

For the PSSCH, the number of RBs occupied depends on the user's payload size, subchannel division, and Modulation Coding Scheme (MCS) used.

A User Equipment (UE), which may be both a transmitter and a receiver, may transmit a data packet including a pscch carrying a message payload; the PSCCH carries control information; and DMRS is a predefined sequence known to all receiving UEs or other receiving devices. UEs in the V2X system, such as vehicle UEs (vues), are always receiving without sending and without knowing which other devices are sending or where the data packets are located. Currently, in order to receive data, a receiving UE needs to perform blind search in the PSCCH resource grid search space and then decode the corresponding PSCCH to obtain data. The entire search space may need to be searched. Therefore, the detection efficiency of PSCCH is low. In some applications, such as the V2X system, the receiving UE is required to accurately decode a certain or defined number of PSSCH payloads as soon as possible to obtain important information.

In V2X, without a priori information on how many PSCCHs and used radio resources of the received PSCCH are present, the VUEs are typically required to detect the PSCCH from up to 10 transmitted VUEs in each subframe and decode the associated PSCCH payload as quickly as possible. Since each PSCCH spans 2 RBs in the resource grid (including consecutive RB pairs), and there are at most M possible RB candidate pairs, where M46 is for a 10MHz bandwidth and M96 is for a 20MHz bandwidth, in the worst case,the VUE may have to blindly search for and detect X.M PSCCH, where X is the possible cyclic shift (n) of each PSCCH DMRS_cs) The number of options. In the case of V2X, X is 4. Such blind processing is computationally very expensive and time consuming and is therefore undesirable at least in the V2X environment.

US9001812 discloses a timing offset/error estimation (TOE) method, e.g. for LTE Uplink (UL) receivers, by using the following equation:

where L is the subcarrier spacing. TO estimate quality by using different values of LThe average value of (d) is increased.

US2018/0332491 discloses a method of detecting a side link identity by making a series of correlations using a DMRS and a set of demodulation reference templates that have been stored in a memory component of the UE.

WO2017/193972 (also disclosed as US2019/0200370) discloses a method for determining resource priority, comprising: processing the PSCCH by performing energy detection to obtain a detection result, and performing information decoding to obtain a decoding result; and weighting at least one of the detection result and the decoding result to determine the priority of the PSCCH resource.

US10165562 discloses a blind detection method and system for a Physical Downlink Control Channel (PDCCH). The method involves acquiring PDCCH data. PDCCH data is used according to a location identifier of a resource element used for a packet. Soft bit data of the control channel element is acquired according to the PDCCH data. The DCI data is acknowledged according to soft-bit data of the CCE. The random access wireless network temporary identifier is acquired according to the DCI data. The PDCCH blind detection is performed based on the random access radio network temporary identifier.

A method for pre-screening a PSCCH step by step along a plurality of received DMRSs is desired in order to speed up a PSCCH detection process, reduce unnecessary processing and power consumption, improve PSCCH detection efficiency, and ensure high detection accuracy.

Object of the Invention

It is an object of the present invention to mitigate or eliminate to some extent one or more problems associated with methods of pre-screening PSCCHs along a plurality of received DMRS to detect a corresponding PSCCH for subsequent decoding of a received channel signal to acquire PSCCH data.

The above object is achieved by the combination of the features of the independent claims; the dependent claims disclose further advantageous embodiments of the invention.

It is another object of the present invention to pre-screen the PSCCH stepwise along a plurality of received DMRS, but not process all of the plurality of received DMRS, in order to speed up the detection process of the PSCCH.

It is yet another object of the present invention to pre-screen multiple PSCCHs and use only the most likely DMRS cyclic shift (n)_cs) To detect the most likely PSCCH candidate.

Other objects of the present invention will be derived from the following description by those skilled in the art. Accordingly, the foregoing object statements are not exhaustive and serve only to illustrate some of the many objects of the present invention.

Disclosure of Invention

The present invention relates to a stepwise pre-screening of a PSCCH along a plurality of received DMRSs, but without necessarily requiring processing of all of said plurality of received DMRSs. The method relates to decoding a PSCCH, wherein for PSCCH candidates in a resource grid, the method comprises the steps of: processing the received DMRS in a subframe of the resource grid associated with the PSCCH candidate to determine one or more potential PSCCHs for decoding, each of the one or more potential PSCCHs being cyclically shifted (n) by a Resource Block (RB) position in the resource grid and a respective DMRS_cs) A value. Repeating this step for at least one other DMRS in the subframe to determine one or more potential PSCCHs for the at least one other DMRS. Then, L PSCCH subsets are selected from the potential PSCCH such that the selected L PSCCH subsets and their corresponding PSCCH subsetsDMRS cyclic shift (n)_cs) The value can be used in a decoding process of the received channel signal.

As a preliminary procedure, the method may include PSCCH resource grid search space reduction, including identifying PSCCH candidates having a signal power less than a first threshold, such that RB pairs including the PSCCH candidates may be excluded from further processing. The search space reduction may additionally or alternatively comprise identifying PSCCH candidates comprising RB pairs wherein the difference in signal power between the RBs making up each RB pair is above a second threshold, and excluding any such RB pair from further processing.

The Timing Offset (TO) compensation may include cyclically correlating the TO compensated received DMRSs and their corresponding local DMRSs TO obtain an energy distribution, a power distribution, or a correlation distribution.

From the energy/power/correlation distribution, a subset of the L validated PSCCHs with the highest energy/power/correlation values may be selected and provided with their respective DMRS cyclic shifts (n) and_cs) A value for a decoding process of the received channel signal.

In a first broad aspect, the invention provides a method of processing a received channel signal, the method comprising: (a) for a physical side link control channel (PSCCH) candidate in a resource grid, processing received demodulation reference signals (DMRSs) in subframes of the resource grid associated with the PSCCH candidate to determine one or more potential PSCCHs for decoding, each of the one or more potential PSCCHs being cyclically shifted (n) by a Resource Block (RB) position in the resource grid and a respective DMRS_cs) A value to identify; (b) repeating step (a) for at least one other DMRS in the subframe to determine one or more potential PSCCHs for the at least one other DMRS; (c) selecting L PSCCH subsets from the potential PSCCH determined by steps (a) and (b); and (d) cyclically shifting (n) the selected L PSCCH subsets and their corresponding DMRSs_cs) The value can be used in a decoding process of the received channel signal.

In a second broad aspect, the invention provides an apparatus for processing a received channel signal, the apparatus comprising: a receiver configured to receive a channel signal, wherein the channel signal comprises a control channel data block of a control channel; and a signal detection module configured to detect a control channel data block of the control channel, wherein the signal detection module comprises machine readable instructions that have been stored in a memory and executed by a processor to perform the steps of the first main aspect of the invention.

In a third broad aspect, the present invention provides a User Equipment (UE) for processing a received channel signal, the UE comprising: a receiver configured to receive a channel signal, wherein the channel signal comprises a control channel data block of a control channel; and a signal detection module configured to detect a control channel data block of the control channel, wherein the signal detection module comprises machine readable instructions stored in a memory and executed by a processor to perform the steps of the first main aspect of the invention.

Other aspects of the invention provide a method of processing a received channel signal, the method comprising performing one or both of the following sets of steps (a) and (b): wherein the set of steps (a) comprises: (i) determining a signal power for a Resource Block (RB) in a resource grid; (ii) comparing the determined signal power of the RB with a selected, calculated or preset first threshold value (Th)₀) Comparing; (iii) identifying the resource grid having a determined threshold (Th) less than the first threshold₀) And excluding from further processing any or all of such RBs; and wherein the set of steps (b) comprises: (i) selecting a candidate RB pair in the resource grid; (ii) determining a signal power of each RB in each pair of candidate RBs in the resource grid; (iii) for each candidate RB pair in the resource grid, determining a difference in signal power between the RBs that make up the RB pair; (iv) comparing the determined signal power difference between the RBs making up the RB pair with a selected, calculated or preset second threshold (Th)₁) Comparing; (v) identifying the determined between the RBs comprising the RB pairIs greater than the second threshold value (Th)₁) And any or all such candidate RB pairs are excluded from further processing.

This summary of the invention does not necessarily disclose all features necessary to define the invention; the invention may reside in a subcombination of the disclosed features.

The foregoing has outlined rather broadly the features of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention.

Drawings

The foregoing and further features of the invention will become apparent from the following description of preferred embodiments, which are provided by way of example only, with reference to the accompanying drawings, in which:

fig. 1 is a schematic block diagram of a channel signal processing apparatus according to the present invention;

fig. 2 is a schematic diagram of an LTE-V2X network in which the concepts of the present invention may be implemented;

fig. 3 is a schematic diagram showing a PSCCH resource grid space with candidate RB pairs;

figure 4 is a schematic diagram illustrating a first method of PSCCH resource grid space reduction according to the present invention;

figure 5 is a schematic diagram illustrating a second method of PSCCH resource grid space reduction according to the present invention;

figure 6 is a schematic diagram illustrating a second method of PSCCH resource grid space reduction when combined with the first method of PSCCH resource grid space reduction;

fig. 7 is a schematic diagram showing TO between different VUEs resulting in DMRS quadrature violations;

figure 8 is a flow chart illustrating a first and second method of PSCCH resource grid space reduction according to the present invention;

FIG. 9 is a flow chart illustrating a first method of TO estimation and compensation according TO the present invention;

FIG. 10 is a flow chart illustrating a second method of TO estimation and compensation according TO the present invention;

fig. 11 is a schematic diagram illustrating a PSCCH resource grid space with multiple received DMRSs;

fig. 12 is a flowchart illustrating an enhanced method for TO estimation and compensation of a plurality of received DMRSs according TO the present invention; and

fig. 13 is another flowchart illustrating an enhanced method for TO estimation and compensation of a plurality of received DMRSs in more detail according TO the present invention.

Detailed Description

The following description is of preferred embodiments by way of example only and is not limited to the combination of features necessary for implementing the invention.

Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. In addition, various features are described which may be present in some embodiments and not in others. Similarly, various requirements are described which may be requirements for some embodiments but not other embodiments.

It should be understood that the elements shown in the fig. may be implemented in various forms of hardware, software or combinations thereof. These elements are implemented in a combination of hardware and software on one or more appropriately programmed general-purpose devices, which may include a processor, memory and input/output interfaces.

This description illustrates the principles of the invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope.

Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include all currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure.

Thus, for example, it will be appreciated by those skilled in the art that the block diagrams presented herein represent conceptual views of systems and apparatus embodying the principles of the invention.

The functions of the various elements shown in the figures may be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software. When provided by a processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared. Moreover, explicit use of the term "processor" or "controller" should not be construed to refer exclusively to hardware capable of executing software, and may implicitly include, without limitation, digital signal processor ("DSP") hardware, read-only memory ("ROM") for storing software, random access memory ("RAM"), and non-volatile storage.

In the claims hereof, any element expressed as a means for performing a specified function is intended to encompass any way of performing that function including, for example, a) a combination of circuit elements that performs that function or b) software in any form, including, therefore, firmware, microcode or the like, combined with appropriate circuitry for executing that software to perform the function. The invention as defined by said claims is intended to cover such a fact: the functionalities provided by the various recited means are combined together as desired by the claims. It is thus regarded that any means that can provide those functionalities are equivalent to those shown herein.

The invention relates to device-to-device wireless communication. The method may include a method for PSCCH search space reduction comprising pre-screening a PSCCH candidate for a PSCCH search space using energy detection, but particularly involving Timing Offset (TO) estimation/compensation of a received channel signal, using a PSCCH candidate, identifying a plurality of DMRS and selecting a PSCCH candidate TO decode the received channel signal based on the DMRS identification. The invention is particularly suitable for the communication system of the vehicle wireless communication technology (V2X).

Fig. 1 shows an exemplary embodiment of a channel signal processing apparatus 100 according to the concepts of the present invention. In the illustrated embodiment, the processing device 100 includes a communication device, such as a handset, UE, network node, V2X unit (e.g., vehicle UE (vue) or roadside unit), etc., operating in a V2X environment (e.g., without limitation, a wireless network, such as a wireless cellular network). The wireless cellular network may comprise a 4G cellular network. It should be understood, however, that the concepts of the present invention are not limited to use in the V2X environment. It will also be understood that the inventive concept does not require the presence or operation of an eNodeB in the communication network.

The processing device 100 may include a number of functional blocks for performing its various functions. For example, the processing device 100 includes a receiver module 110 that provides received signal processing and is configured to provide received signals and/or information extracted therefrom to a function block module (or function blocks) 120, which function block module 120 may include, for example, various data receivers, a control element (or elements), a user interface (or user interfaces), and so forth. Although the receiver module 110 is described as providing received signal processing, it should be understood that the functional blocks may be implemented as transceivers providing transmit and receive signal processing. Regardless of the particular configuration of the receiver 110, embodiments include a signal detection module 130 disposed in association with the receiver module 110 for facilitating accurate processing and/or decoding of received channel signals in accordance with the present invention. The multiple channel signals may be received by the antenna module 105. Furthermore, when the transmitting station identifier information is not known, or more particularly, is not provided as is typically the case in the side-link of a V2X system, the receiver module 110 is configured to process and/or decode the received channel signal.

Although the signal detection module 130 is shown as being deployed as part of the receiver module 110 (e.g., including part of the receiver module control and logic circuitry), there is no limitation on this deployment configuration in accordance with the concepts of the present invention. For example, the signal detection module 130 may be deployed as a functional block of the processing device 100 that is distinct from the receiver module 110 but connected to the receiver module 110. The signal detection module 130 may be implemented, for example, using logic circuits and/or executable code/machine readable instructions that have been stored in the memory 140 of the processing device 100 for execution by the processor 150 to perform the functions described herein. For example, executable code/machine-readable instructions may have been stored in one or more memories 140 (e.g., Random Access Memory (RAM), Read Only Memory (ROM), flash memory, magnetic memory, optical memory, etc.), the one or more memories 140 being adapted to store one or more sets of instructions (e.g., application software, firmware, operating systems, applets, etc.), data (e.g., configuration parameters, operating parameters and/or thresholds, collected data, processed data, etc.), and so forth. The one or more memories 140 may include a processor-readable memory for use with the one or more processors 150, the processors 150 operable to execute code segments of the signal detection module 130 and/or utilize data provided thereby to perform the functions of the signal detection module 130 described herein. Alternatively or in addition, the signal detection module 130 may include one or more special-purpose processors (e.g., an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a Graphics Processing Unit (GPU), etc.) configured to perform the functions of the signal detection module 130 described herein.

As described in more detail below, the signal detection module 130 is configured to implement PSCCH resource grid search space reduction, estimation and compensation of timing offset of the received channel signal, and DMRS symbol identification.

Although the following description refers to LTE-V2X networks by way of example, it will be appreciated that the concepts of the present invention are adaptable to New Radios (NRs), i.e. 5G, broadcast networks, and in particular, but not exclusively, to LTE-V2X evolution of 3GPP Release 15 to support applications such as 5G-V2X communications and autonomous vehicles.

The LTE-V2X channel bandwidth is divided into a given number of subchannels. Each subchannel has a plurality of Resource Blocks (RBs) having 12 subcarriers. The two primary physical channels used in LTE-V2X include multiple PSCCHs used to transmit data packets in multiple Transport Blocks (TBs) and multiple PSCCHs used to transmit associated side link control information (SCI). The PSCCH SCI and its associated psch TB may be transmitted in the same subframe or in different subframes.

The PSCCH always occupies two RBs. DMRS carrying PSCCH with cyclic shift (n)_cs) Sequence of 24-bit sampled complex values of the parameter, cyclic shift (n)_cs) The parameters define how "fast" the DMRS sequence rotates in the complex plane. Cyclic shift (n)_cs) The values are chosen randomly by the transmitter, so the receiver does not know which cyclic shift (n)_cs) The value has already been selected. With different cyclic shifts (n)_cs) DMRSs of values are mutually orthogonal. In V2X, there are four possible cyclic shifts (n)_cs) Value, i.e. n_cs0,3,6 or 9.

In V2X, without a priori information on how many PSCCHs and radio resources used by the received PSCCH are present, the VUEs are typically required to detect the PSCCH from up to 10 transmitted VUEs in each subframe and decode the associated PSCCH payload as quickly as possible. Each PSCCH spans 2 RBs (including consecutive RB pairs) in the resource grid, and there are at most M possible RB candidate pairs, where M46 is for a 10MHz bandwidth and M96 is for a 20MHz bandwidth. In the worst case, the VUE may have to blindly search for and detect the 4M PSCCH because there are four possible cyclic shifts (n) for each PSCCH DMRS_cs) And (6) selecting options.

Referring to fig. 2, in a conventional uplink/downlink LTE network scenario, two UEs 205 typically communicate over a radio link 206 using the LTE "Uu" interface, and data always passes through the LTE eNodeB 210. In contrast, the edge link 211 enables the use of a "PC 5" interface to include multiple VUIes (VUIE)_R、VUE₁、VUE₂)215, 220, 225 to communicate directly between the near-end UEsAnd data does not need to pass through the eNodeB 210. It is to be appreciated that in the V2X network of fig. 2, all devices including multiple UEs 205, multiple VUEs 215, 220, 225 and roadside unit(s) 230 may communicate via side link 211, thereby eliminating participation of eNodeB 210.

In the example of FIG. 2, which is provided for illustration only, the VUE_R215 from at least VUE₁220 and VUE₂225 receives the channel signal (psch/PSCCH). As shown, VUE₁220 ratio VUE₂225 closer to the VUE_R215, make VUE_RVUE at 215₁220 has a signal strength greater than VUE_RVUE at 215₂225. This can be better understood with reference to FIG. 4, where it can be seen that in the VUE_RVUE at 215₁220 RB signal power stronger than in VUE_RVUE at 215₂225 of the RB.

FIG. 3 illustrates a diagram for a VUE_R215 are identified in VUE_RFrom VUE at 215₁220 and VUE₂225 RB resource grid of the received channel signal (PSCCH RB).

In a first method of PSCCH resource grid space reduction according to the present invention, as illustrated by the set of steps (a) of figure 8, the method comprises a first co-synchronization step 300 of receiving one or more channel signals (e.g. PSCCH) at the channel signal processing apparatus 100. As shown in fig. 3, the received PSCCH occupies RB pairs within the resource grid. In this example, some of the RBs in the resource grid are unused. The first PSCCH space reduction method includes the next step 305 of determining a signal power for each RB in the resource grid using the signal receiver module 110 and/or the signal detection module 130. As shown in FIG. 4, a next step 310 involves comparing the determined signal power of each RB with a selected, calculated or preset first threshold (Th)₀) A comparison is made. Then, in step 315, it is identified and/or marked that there is a determined sub-first threshold (Th) in the resource grid₀) Such that at step 320 the RB can be identified for further processing from the method of the present inventionAnd (4) excluding. First threshold value (Th)₀) Selected, calculated, or preset by off-line theoretical analysis, simulation analysis, field-in-the-field testing, and/or online adaptation. The first PSCCH space reduction method provides a computationally efficient way to significantly reduce the PSCCH search space.

Preferably, the signal power for the RBs determined by the signal receiver module 110 and/or the signal detection module 130 is determined at the DMRS of each RB, and preferably further at Orthogonal Frequency Division Multiplexing (OFDM) symbols of the DMRS of the RB. Further, preferably, the signal power is determined only for RBs with DMRS.

In a second method of PSCCH resource grid space reduction according to the present invention, as shown in the set of steps (b) of figure 8, the method is based on the selected plurality of candidate RB pairs. Alternatively (as shown in fig. 5) or in addition (as shown in fig. 6) to the first PSCCH space reduction method, a second PSCCH space reduction method may be implemented.

In the case shown in fig. 5, four possible consecutive candidate RB pairs are shown, denoted as "candidate 1", "candidate 2", etc. After the first co-synchronization step 300, the first embodiment of the second PSCCH space reduction method calls for the selection of candidate RB pairs at step 325. In this embodiment of the method, no RB has been marked to exclude further processing, i.e. in this case the first PSCCH space reduction method described above has not been used. In a next step 330, the signal receiver module 110 and/or the signal detection module 130 determines the signal power of each RB in each pair of candidate RBs in the resource grid. Then, in step 335, the difference in signal power between the RBs making up the RB pair is determined. In step 340, the difference between the signal powers of the RBs in the determined candidate RB pair is compared to a selected, calculated or preset second threshold (Th)₁) A comparison is made. For example, the "candidate 1" RB pair in fig. 5 is determined to see whether the difference between the signal powers indicated as "1" is larger than the second threshold value (Th)₁) I.e. 1>Th₁. For a "candidate 1" RB pair, determining that the difference in signal power between the two RBs forming the candidate pair is less than Th₁. Thus, like "candidate 4" RB to oneLikewise, the "candidate 1" RB pair is reserved for further processing; but the "candidate 2" RB pair and the "candidate 3" RB pair are excluded from further processing. The difference of power signals comparing step 340 enables identification of any RB pair at step 345, wherein the determined difference of signal power between the RBs making up the RB pair is greater than a second threshold (Th)₁). This then results in step 350, wherein any such candidate RB pair is identified for exclusion from further processing by the method of the present invention. Second threshold value (Th)₁) Selected, calculated, or preset by off-line theoretical analysis, simulation analysis, field-in-the-field testing, and/or online adaptation.

In a second embodiment of the second PSCCH space reduction method as shown in fig. 6, the second PSCCH space reduction method (set of steps (b)) is performed after the first PSCCH space reduction method (set of steps (a)) is performed. This has the following advantages: the selection of candidate RB pairs in step 325 is modified because some RBs have been excluded from further processing as a result of the first PSCCH space reduction method and therefore are not included in the selection of candidate RB pairs for the second PSCCH space reduction method. Therefore, as shown in fig. 6, in the second embodiment of the second PSCCH space reduction method, the "candidate 2" RB pair and the "candidate 3" RB pair (fig. 5) are not considered, but the "candidate 1" RB pair and the "candidate 4" RB pair are selected.

Preferably, the RB candidate pair is selected as a contiguous pair of RBs from any valid RBs, i.e. RBs that have not been excluded from further processing.

It should be noted that the first PSCCH space reduction method seeks to be at the receiver module 110 (VUE)_R) RBs with very low signal power are excluded, while the second PSCCH space reduction method seeks to exclude RB pairs where there is a large difference in signal power between the RBs making up the pair.

Referring TO fig. 7 and also TO fig. 2, the Timing Offset (TO) problem is illustrated whereby TO may occur at the receiver VUE due TO conditions such as non-ideal GNSS and/or fading channels. In the network environment example of FIG. 2, it can be seen in FIG. 7 that, relative to the VUE₁VUE of_RWhere there is a unique TORelative to VUE₂VUE of_RThere is another unique TO. The TO between the receiver and the transmitter violates the orthogonality of the DMRS.

As shown in fig. 9 and 10, the present invention proposes a TO estimation and compensation method TO solve the problem shown in fig. 7. It is highly preferred that the TO estimation and compensation method described below is performed after performing the first PSCCH space reduction method and/or the second PSCCH space reduction method such that the TO estimation and compensation is limited TO approved candidate RB pairs, wherein the approved candidate RB pairs include RB pairs, wherein a difference in the determined signal power between the RBs making up the RB pair is less than or equal TO a second threshold (Th)₁). However, the TO estimation and compensation method may be performed without first performing the first PSCCH space reduction method and/or the second PSCCH space reduction method.

After a channel signal (PSCCH) has been received at step 400 (fig. 9), the signal detection module 130 is configured to select a candidate RB pair from a PSCCH resource grid of the received channel signal at step 405. For each selected (approved) candidate pair, the signal detection module 130 is configured to base the selected plurality of different local DMRSs (l) at step 410₀，l₃，l₆And l₉) Making a Timing Offset (TO) estimate TO provide an estimated TOs for the received PSCCH (TAnd) Selected plurality of different local DMRS (l)₀，l₃，l₆And l₉) With a corresponding number of cyclic shifts (n)_cs0,3,6, 9). In a V2X environment, a plurality of different selected local DMRSs (l)₀，l₃，l₆And l₉) Comprising 4, with 4 corresponding cyclic shifts (n)_cs0,3,6,9) to provide 4 estimated TOs(s) ((s)(s) ((s))And). Said 4 estimated TOs (c: (c))And) Preferably determined by the following equation:

wherein:

y is the received DMRS

l_ncsIs provided with cyclic shift n_csLocal DMRS of

i is the subcarrier index

N_FFTIs the FFT length

(·)^*: is a complex conjugate operation

K_sIs a configurable interval.

Interval K_sIs configurable so that the correct cyclic shift can be automatically identified after TO compensation and local DMRS correlation. For example, for embodiments in LTE V2X release, K_sBetween 4 and 12, contains the boundary.

In a next step 415, the signal detection module 130 is configured to use the estimated TOs(s) ((s))And) TO compensation TO obtain TO compensated receive DMRS: (And). Each of the TO-compensated DMRSs is preferably determined by the following formula:

wherein the content of the first and second substances,stands for TO compensated DMRS, andrepresenting the received DMRS. i.e. i₀Is the starting index in the frequency domain of the current PSCCH.

In an ideal case without noise, the received DMRS is only affected by TO, and then the ith element of the received time-shifted DMRS can be represented as:

will be provided withSubstituting TO estimate equation gives:

only the part inside the angle function is of interest and is calledThe equation:

the third bracket on the right can be simplified and taken from the sum because it is independent of the sum index i:

the part of the summation can be further simplified according to the orthogonal property:

where γ represents the summed amplitude portion.

In the presence of the correct n_csThe condition for then making a correct TO estimate is that the angle function should not wrap around (wrap-around). This means that:

in this case, K_sIs limited by the maximum value of TO, which is given by the maximum length of the cyclic shift in the LTE system, i.e. TO_max168, which results in K_sWhen NFFT is 2048 as an integer, Ks, max is 12.

In using the wrong n_csThe condition leading TO a wrong TO estimation is that the angle function wraps around, which will lead TO a weak peak in the energy/power/correlation distribution that follows in the subsequent step. This means that:

comparing TO induced phase accumulation, by wrong n_csThe phase accumulation caused by the selection is the main factor in the summation.

Therefore, we can relax the conditions:

which result in K_sThe lower limit of (2) is 4 as follows:

then, in step 420, the signal detection module 130 is configured TO cyclically associate TO compensated received DMRSs(s) ((s)),(s)And) And its corresponding local DMRS (l)₀，l₃，l₆And l₉) And obtaining a cyclically associated TO compensated received DMRS: (And) And its corresponding local DMRS (l)₀，l₃，l₆And l₉) Energy/power/correlation distribution. In a next step 425, the signal detection module 130 is configured TO obtain the energy distribution (for the received DMRS compensated for the cyclically associated TO: (for the cyclically associated TO:)And) And its corresponding local DMRS (l)₀，l₃，l₆And l₉) Acquired) normalized energy/power-Correlation distribution (z)₀，z₃，z₆And z₉). Normalized energy/power/correlation distribution (z)₀，z₃，z₆And z₉) Obtaining by (A): received DMRS with cyclically associated TO compensation: (And) And its corresponding local DMRS (l)₀，l₃，l₆And l₉) Is squared and then divided by the average of the squares of the energy/power/correlation distributions. The use of (a) is technically unexpectedly beneficial because any non-distinct peak from the average, while having a high absolute energy in itself, will not be listed as a high peak after the normalization process.

For each normalized energy/power/correlation distribution (z)₀，z₃，z₆And z₉) The signal detection module 130 is configured to identify a maximum peak of the normalized energy/power/correlation distribution based on the peak power level at step 430; in step 435, the power value of the maximum peak is compared to a selected, calculated or preset third threshold (Th)₂) Comparing; if the power value of the maximum peak value is greater than or equal to the third threshold value (Th)₂) Then, in step 440, the corresponding DMRS cyclic shift (n) is stored or provided_cs) The power value of the maximum peak value with which a value is associated (and preferably with the corresponding candidate pair index value). Each possible DMRS cyclic shift (n) for each RB candidate pair_cs) The foregoing steps are performed. Third threshold value (Th)₂) Selected, calculated, or preset by off-line theoretical analysis, simulation analysis, field-in-the-field testing, and/or online adaptation.

Preferably, the method further comprises steps 440A-C as shown in FIG. 10, including: stored energy of approved candidate RB pairs in order of stored power value from highest to lowestThe quantity/power/correlation values are sorted (step 440A); defining (step 440B) L subsets with respect to the stored energy/power/correlation values, starting from the highest value, the size of the subsets being preset, selected or calculated; and causing (step 440C) the highest stored energy/power/correlation value in the selected L subsets and its corresponding DMRS cyclic shift (n £ C)_cs) The values may be used in a decoding process of the received channel signal. L is a target number of PSCCH candidates that are passed to the channel signal processing apparatus 100 for decoding PSCCH and PSCCH Packet Data Units (PDUs). The target number should be no less than the required number of PSCCH/pschs to be decoded conventionally, nor more than the sustainable number of PSCCH/pschs to be decoded by the basic computational power of the channel signal processing apparatus 100 (edge link decoder).

Selected L subsets of the stored energy/power/correlation values, their corresponding DMRS cyclic shifts (n)_cs) The values and their corresponding candidate pair index values are used by the signal detection module 130 to decode the received pscch signal to obtain payload data. The selected L subsets may be used in a subsequent PSCCH/PSCCH decoding process.

The above-described method of the present invention greatly reduces the computational effort of the signal detection module 130 because L < M, a computationally expensive channel estimation, demodulation, and convolutional encoding process in a conventional channel signal decoder, need only be performed L times instead of up to X.M times (up to 4M times in a V2X environment). Simulation results indicate that the effective value of L can be in the range of 10 to 20, which is very advantageous compared to values of M-46 (10MHz) or 96(20 MHz). This saves processing costs and simplifies hardware design compared to conventional channel signal processing devices. The invention provides a PSCCH pre-screening scheme with low complexity and acceptable accuracy.

The foregoing methods, particularly those described with respect to fig. 9 and 10, are suitable for all devices where it is desirable to reduce or minimize processing overhead, and are particularly suitable for low power devices. The methods described with respect to fig. 9 and 10 involve detecting the PSCCH for decoding using a single DMRS in a subframe. The single DMRS used may include a DMRS received first in the subframe. However, for higher power devices, the PSCCH may be pre-screened stepwise along multiple received DMRSs in a subframe in order to improve the PSCCH detection process. However, in order to reduce unnecessary processing and power consumption while still improving PSCCH detection efficiency and achieving high detection accuracy, it is proposed to pre-screen PSCCHs along multiple received DMRSs until an appropriate number of potential PSCCHs for decoding are identified or determined to enable selection of a validated subset of potential PSCCHs. In this way, it has been found that processing all of the plurality of received DMRSs can be avoided while improving the PSCCH detection procedure.

The following description describes enhancement methods derived from aspects of the invention that have been described herein with reference to fig. 1-10; the enhanced method is configured to progressively process two or more of the plurality of received DMRSs in a subframe, thereby enabling more accurate PSCCH detection while still limiting the throughput of the plurality of received DMRSs to maintain good delay. In other words, the enhancement method described below achieves a balance between the enhanced accuracy of PSCCH detection without significantly increasing the delay of PSCCH detection. The enhancement method uses substantially the same processing steps as those used in the method described with reference to fig. 1 to 10 for each of the plurality of received DMRSs, although any modifications are described below. The enhancement method may be implemented by the channel signal processing apparatus of fig. 1.

Fig. 11 is a diagram illustrating a PSCCH resource grid space with multiple received DMRSs, denoted DMRSs respectively₁To DMRS₄Wherein the DMRS₁To DMRS₄Indicating that the total number of DMRSs in a subframe is 4 in this example. Furthermore, there are 4 possible cyclic shifts (n)_cs) Value, i.e. n_cs0,3,6 or 9. However, the enhancement method is not limited to 4 DMRSs in a subframe or the above cyclic shift (n)_cs) The value is obtained.

Referring to fig. 12, which includes a flowchart illustrating an enhanced method of processing multiple received DMRSs according to the present invention, preferably, a first method of performing PSCCH space reduction (set of steps (a) of fig. 8) and/or a second method of performing PSCCH space reduction (set of steps of fig. 8)After step (b)), performing processing of the plurality of received DMRSs such that processing of the plurality of received DMRSs is limited to PSCCH candidates, wherein the selected PSCCH candidates include RB pairs, wherein a signal power difference determined between RBs making up the RB pair is less than or equal to a second threshold (Th)₁). However, the enhancement method of fig. 12 may be implemented without first implementing the first method of PSCCH space reduction and/or the second method of PSCCH space reduction of fig. 8.

After a channel signal (PSCCH) has been received at step 500 (fig. 12), the signal detection module 130 is configured to select PSCCH candidates comprising RB pairs from a PSCCH resource grid of the received channel signal at step 505. For the selected PSCCH candidate, the signal detection module 130 is configured to process, at step 510, one of a plurality of received DMRSs in a subframe associated with the selected PSCCH candidate to determine one or more potential PSCCHs for decoding. The one of the plurality of received DMRS that is processed is preferably the first of the plurality of received DMRS in the associated subframe, e.g. DMRS₁. By processing DMRS₁Each of the determined one or more potential PSCCHs is preferably cyclically shifted (n) by a DMRS including a Resource Block (RB) position and a corresponding DMRS in a resource grid_cs) Data of values. The identification data may also include respective index numbers for one or more potential PSCCHs.

The potential PSCCH for decoding determined from processing some of the multiple received DMRSs is subjected to a validation process, as will be described more fully below. However, it is preferred that the threshold value (Th), which is referred to herein before as the "third threshold value (Th 2)" for the verification process₂) Is determined, selected or calculated to have a value or level such that the DMRS from processing the first received DMRS₁The determined number of potential PSCCHs for decoding is less than the required or desired number L, such that at decision block 515, the signal detection module 130 is required to repeat step 510 for at least another one of the plurality of received DMRSs, e.g., at the DMRS₂，DMRS₃Or DMRS₄At least one other of the above. Therefore, an adjustable threshold (Th) is preferred₂) Is designed such that the enhancement method of fig. 12 requires two or more of a plurality of received DMRSs to be processed. Preferably, in case more than one such other DMRS needs to be processed, the other DMRSs processed according to the repetition of step 510 are processed in their order of reception.

DMRS with a second DMRS₂Will be described from DMRS in step 520 according to the repeated step 510₂Processing the determined identification data for the one or more potential PSCCHs with the secondary DMRS₁The identification data determined for the one or more potential PSCCHs are stored together. Preferably, from DMRS₁Is then processed through the DMRS₂Determines a sufficient number of potential PSCCHs such that it implements a number F of validated potential PSCCHs greater than or equal to L. In the case where F ≧ L, there is no need to process any of the remaining plurality of received DMRSs. In the case where F < L, step 510 must be repeated to process one or more remaining DMRSs until F is at least equal to L or until the last remaining DMRS is processed.

The values L and F may be selected, calculated or preset by off-line theoretical analysis, simulation analysis, field testing and/or on-line adaptation, respectively.

In step 525, the signal detection module 130 processes at least the DMRS₁And DMRS₂Selecting a subset of the determined potential PSCCHs. L is a target number of PSCCH candidates passed to the channel signal processing apparatus 100 for decoding PSCCH and PSCCH PDUs. The target number should be no less than the required number of PSCCH/pschs to be decoded conventionally, and no greater than the sustainable number of PSCCH/pschs to be decoded by the basic computational power of the channel signal processing apparatus 100 (edge link decoder).

In step 530, the signal detection module 130 cyclically shifts (n) the DMRSs with their respective DMRSs_cs) Selected L PSCCH subsets of values may be used in the decoding process of the received channel signal.

At step 520, the signal detection module 130 may be configured to select potential PSCCHs sharing a common characteristic from among the potential PSCCHs stored at step 515. This may include LSubset selection with same RB position and same DMRS cyclic shift (n) in resource grid_cs) Potential PSCCH of values.

Threshold value (Th)₂) Preferably adjustable on a per subframe basis. Furthermore, after ending the selection of the L PSCCH subsets at step 525 or step 530, the method may include adjusting a threshold (Th) for verifying the potential PSCCH based on the final number F of verified potential PSCCHs₂) The step (2). For example, if the final number F of potential PSCCHs verified is equal to or greater than the number L of subsets of the PSCCH, the method may comprise increasing the threshold (Th)₂) For subsequent verification of the potential PSCCH. Conversely, if the final number F of potential PSCCHs validated is less than the number L of subsets of PSCCHs, the method may comprise reducing the threshold (Th)₂) For subsequent verification of the potential PSCCH.

In the case where the number F of validated potential PSCCHs remains less than the number L of subsets of PSCCHs after all DMRS in the subframe have been processed, then the L PSCCH subsets may form the number L by including the unverified potential PSCCH, as will be described more fully below.

The enhancement method broadly illustrated by fig. 12 is illustrated in more detail by fig. 13. Referring to fig. 13, a flow chart illustrates the enhancement method in more detail. A first step 600 of the method includes the signal detection module 130 receiving a channel signal (PSCCH). However, as already described with respect to fig. 12, the method 600 may include the signal detection module 130 first implementing the first method of PSCCH space reduction (set of steps (a) of fig. 8) and/or the second method of PSCCH space reduction (set of steps (b) of fig. 8), although this is not necessary for the implementation of the method.

In a next step 610, the signal detection module 130 initializes the list of potential PSCCHs for decoding (or their RB equivalents) to null and to have a value denoted F₀The size of (2). In addition, in step 610, the signal detection module 130 initializes an index of the received DMRS being processed to i-1, where the number of DMRSs in a subframe is a value N, e.g., for V2X, N-4 DMRSs (including DMRSs 1 to DMRSs 4).

In step 620, the signal detection module 130 performs a Timing Offset (TO) estimation on the plurality of received DMRSs for each PSCCH candidate using each cyclic shift and using the ith received DMRS TO provide an estimated TO. In the example of the network environment of FIG. 2, it is assumed that a VUE is received_RAnd each transmitting VUE (e.g., VUE)₁And VUE₂) The timing offset between is relatively constant over the sub-frames. For a selected PSCCH candidate in the ith DMRS, assuming a kth cyclic shift, a TO estimate is made for each PSCCH candidate using the first i received DMRS according TO:

wherein:

{y_j}: is the jth received DMRS

{l_k}: is with the kth cyclic shift n_csLocal DMRS of

N_FFT: is the FFT length

P: is the subcarrier index

(·)^*: is a complex conjugate operation, and

K_sis a configurable interval.

Configurable parameter K_sRepresenting the length of the interval between two associated segments to obtain the phase/time difference. Interval K_sIs configurable so that the correct cyclic shift can be automatically identified after TO compensation and local DMRS correlation. For example, for embodiments in LTE V2X release, K_sBetween 4 and 12, contains the boundary.

In step 630, the signal detection module 130 uses the code with respective cyclic shifts (n)_cs) The 4 estimated TOs with the value of 0,3,6,9 are TO compensated TO provide TO compensated received DMRSs. Furthermore, at step 630, the signal detection module 130 is configured TO cyclically associate the TO-compensated receiving DMRS and its corresponding local DMRS, and then obtain the energy/power/correlation score obtained for the cyclically associated TO-compensated receiving DMRS and its corresponding local DMRSNormalized energy/power/correlation distribution of the cloth. The normalized energy/power/correlation distribution is obtained by taking the magnitude square of the correlation result and accumulating it on the ith DMRS, i.e., taking the magnitude square of the energy/power/correlation distribution of the cyclically correlated TO-compensated received DMRS and its corresponding local DMRS, and then dividing by the average of the squares of the energy/power/correlation distributions. Using the kth n at a resource grid potential PSCCH location q_csThe real-valued sequence of the ith DMRS of the option is denoted as z_i,k,q. Due to random residual phase caused by channel fading, the square of the amplitude of the cyclic correlation result should be obtained first before accumulating the cyclic correlation result through multiple DMRSs to avoid destructive combination.

In step 640, the signal detection module 130 performs size-reduced effective peak sorting on the plurality of received DMRSs by using the normalized energy/power/correlation distribution obtained by the average value and identifying a maximum peak of the normalized energy/power/correlation distribution. Then, for the threshold (Th)₂) The maximum peak is verified and then all valid peaks are sorted. After traversing all candidates, the signal detection module 130 outputs φ including the maximum peak for run-in_i。φ_iIs the total useful candidate (potential PSCCH) (i.e., L) for decoding and up to the previous symbol (i.e., F)_i-1) Is selected as a function of the accumulated potential PSCCH. If phi is_iLess than the number of valid peaks, all valid potential PSCCHs are output. The outputted valid potential PSCCH is stored as C_i。

More specifically, to process the ith DMRS in each subframe, the method applies a sequence z_i,k,qNormalized by its mean value. Then, find each normalized z_i,k,qAnd represent them as s_i,k,q。

For each potential PSCCH used for decoding, the method records the DMRS cyclic shift hypothesis k with the highest of the four peaks^*Is also valid (i.e. the peak is larger than a (configurable and/or adjustable) threshold (Th)₂)). If potential PIf the SCCH has any valid peaks, then its location is stored and its corresponding DMRS cyclic shift (n) is recorded_cs) The value is obtained.

After traversing all determined potential PSCCHs, the number of valid peaks is recorded as M_i. The effective peaks are sorted in descending order, highest phi_iThe potential PSCCH is output as a valid potential PSCCH that contains the ordered result for the just-processed received DMRS. The output is phi_iA list of entries, each entry consisting of a validated potential PSCCH index q (i.e. resource block location), the cyclic shift giving the candidate k^*Highest correlation peak and peak of

Thus, phi_i＝f(L,F_i-1) Where L is the total number of candidates required for decoding and F_i-1Is the number of in-range candidates up to the (i-1) th DMRS. When phi is_i>M_iAll valid potential PSCCHs will be output.

The enhanced method of fig. 13 provides a method of progressively processing a received channel signal in a device-to-device communication link using a plurality of reference symbols, and further includes the following steps.

In step 650, the signal detection module 130 performs validated bounded potential PSCCH candidates using a consistency check with two or more received multiple DMRSs. From the processing of the second received plurality of DMRS, the signal detection module 130 starts at C_iAnd C_i-1The common candidates in the search, i.e. candidates with the same RB position and the same DMRS cyclic shift value, are denoted D_i. If the number of common candidates is less than (L-F)_(i-1)) Then D is_iAll candidates in (1) will go into bounds, otherwise at D_iIn (A) has (L-F)_(i-1)) Candidate entries for the highest peaks. Updating the validated potential PSCCH (F) at step 655 by accumulating the enlisted (shortlisting) validated potential PSCCH for decoding_i) A list of (a). If F_iGreater than or equal to L, the validated potential PSCCH required for decoding is found and extracted for decoding,and the screening (shortlisting) process terminates. The method may then detect the potential PSCCH for decoding by ending the procedure without processing all of the received multiple DMRSs for the selected PSCCH candidate, and may move to steps 525 and 530 of fig. 12. In addition, the method may proceed to adjust a threshold (Th) for validating the potential PSCCH based on the final number F of validated potential PSCCHs₂) Optional steps of (1). However, if F_iIf less than L, steps 620 to 650 are repeated until F_iGreater than or equal to L or until all of the received plurality of DMRSs have been processed.

More specifically, step 650 includes starting with the processing of the ith (i ≧ 2) received plurality of DMRSs, and then applying C_iPotential validated PSCCH and C in (1)_i-1Are compared and a common set of validated potential PSCCHs, i.e. stored validated potential PSCCHs with the same PSCCH candidate index i and cyclic shift value k, is obtained therefrom. Then, if | D_i|≤(L-F_i-1) Set up R_i＝D_iEnqueuing all validated potential PSCCHs in the detected PSCCH list_iOtherwise, R is_iIs arranged at D_iIn (A) has (L-F)_i-1) A highest valueVerified potential PSCCH. By removing R_iUpdate C_iAnd by adding the current number of incoming validated potential PSCCHs to F_i＝F_i-1+|R_iL to obtain F_iThe value of (c). If F_iGreater than or equal to L, the required number of validated potential PSCCHs to be entered is found.

At step 660, the signal detection module 130 performs a verified potential pscch re-screening on the last DMRS. If after the consistency check in step 650F_N<L, then the method involves enclosing in C_NHas the highest (L-F) among_N) The remaining potential PSCCHS of each normalized peak (excluding the common validated potential PSCCHS). The final L potential PSCCHs are selected for subsequent decoding processes and filteredThe process terminates. The method may then move to steps 525 and 530 of fig. 12 by ending the process of detecting the potential PSCCH for decoding, although in this case it is necessary to process all of the received multiple DMRSs for the initially selected PSCCH candidate. In addition, the method may proceed to adjust a threshold (Th) for validating the potential PSCCH based on the final number F of validated potential PSCCHs₂) Optional steps of (1).

Step 670 includes storing identification data for the validated potential PSCCH.

Step 680 includes an optional step of adjusting the threshold (Th) used to validate the potential PSCCH based on the final number F of validated potential PSCCHs or the threshold adaptation used for false peak cancellation₂). This step involves adjusting the threshold (Th) for peak validation according to the number of final entry candidates when the entire screening process has terminated₂). The adjustment of the threshold is done on a per subframe basis, such that:

if F_N>L, then Th will be₂Increase to alpha, Th₂In which α is>1 is configurable;

if F_N<L, then Th will be₂Decrease to beta, Th₂Wherein 0 is<β<1 is configurable.

Otherwise, Th₂Remain unchanged.

The above means may be implemented at least partly in software. Those skilled in the art will appreciate that the above-described apparatus may be implemented, at least in part, using general purpose computer equipment or using custom equipment.

Here, aspects of the methods and apparatus described herein may be performed on any apparatus including a communication system. Program aspects of the technology may be considered to be an "article of manufacture" or an "article of manufacture" typically represented by code and/or associated data, carried or embodied by a machine-readable medium. "storage" type media includes any or all of the memory of a mobile station, computer, processor or similar device, or associated module, such as the various semiconductor memories, tape drives, disk drives or similar drives, which may provide storage for software programming at any time. The entire software or portions thereof may sometimes be in communication via the internet or various other communication networks. For example, the communication may cause the load of the software to be transferred from one computer or processor to another computer or processor. Thus, another type of medium that may carry software components includes optical, electrical, or electromagnetic waves traversing wired, optical, landline and various wireless links, e.g., a cross-physical interface used between local devices. The physical components (e.g., wired or wireless lines, optical links, or the like) that carry these waves can also be considered a medium that carries software. As used herein, unless defined as a tangible, non-transitory "storage" medium, the term "computer-or machine-readable medium," for example, may be any medium that provides instructions to a processor for execution.

While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered as exemplary and not restrictive in character, it being understood that the illustrated and described embodiments are exemplary only and do not limit the scope of the invention in any way. It is to be understood that any of the features described herein can be used with any of the embodiments. The illustrated embodiments are not mutually exclusive and do not exclude other embodiments not described herein. Accordingly, the present invention also provides embodiments comprising a combination of one or more of the above-described embodiments. Modifications and variations may be made to the invention as described herein without departing from the spirit and scope of the invention. Accordingly, the invention should be limited only as indicated by the appended claims.

Unless the context requires otherwise, due to express language or necessary implication, in the claims following the description of the invention, the word "comprise", or variations such as "comprises" or "comprising", is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

It will be understood that, if any prior art publications are referred to herein, such reference does not constitute an admission that the publications are known in the art.

Claims (27)

1. A method of processing a received channel signal, the method comprising:

(a) for a physical side link control channel (PSCCH) candidate in a resource grid, processing received demodulation reference signals (DMRSs) in subframes of the resource grid associated with the PSCCH candidate to determine one or more potential PSCCHs for decoding, each of the one or more potential PSCCHs being cyclically shifted (n) by a Resource Block (RB) position in the resource grid and a respective DMRS_cs) A value to identify;

(b) repeating step (a) for at least one other DMRS in the subframe to determine one or more potential PSCCHs for the at least one other DMRS;

(c) selecting L PSCCH subsets from the potential PSCCH determined by steps (a) and (b); and

(d) cyclically shifting (n) the selected L PSCCH subsets and their corresponding DMRS_cs) The value can be used in a decoding process of the received channel signal.

2. The method of claim 1, further comprising the step of determining PSCCH candidates in the resource grid before performing steps (a) - (d).

3. The method of claim 1, wherein step (c) comprises selecting any one of the potential PSCCH determined from step (a) and the potential PSCCH determined from step (b) that have a common characteristic.

4. The method of claim 3, in which the common characteristic comprises a same RB position and a same DMRS cyclic shift (n) in the resource grid_cs) The value is obtained.

5. The method of claim 1, wherein after performing steps (a) and (b), when the number F of validated potential PSCCHs is equal to or greater than the number L of PSCCH subsets, then step (b) is not repeated for another DMRS in the subframe.

6. The method of claim 1, wherein after performing steps (a) and (b), when the number F of validated potential PSCCHs is less than the number L of PSCCH subsets, then repeating step (b) for another DMRS in the subframe.

7. The method of claim 6, wherein, after processing all DMRSs in the subframe, when the number F of validated potential PSCCHs remains less than the number L of PSCCH subsets, then the L PSCCH subsets constitute a number L by including unverified potential PSCCHs.

8. The method of claim 1, wherein after terminating selection of the L subsets of PSCCHs, a threshold for verifying potential PSCCHs is adjusted according to a final number F of verified potential PSCCHs.

9. The method of claim 8, wherein the step of adjusting the threshold for verifying a potential PSCCH is performed on a per subframe basis.

10. A method according to claim 8, wherein when the final number F of verified potential PSCCHs is equal to or greater than the number L of PSCCH subsets, then the method comprises the step of increasing the threshold for subsequent verification of potential PSCCHs, or when the final number F of verified potential PSCCHs is less than the number L of PSCCH subsets, then the method comprises the step of decreasing the threshold for subsequent verification of potential PSCCHs.

11. The method of claim 1, wherein PSSCH candidate comprises any RB pair in the resource grid having less than or equal between the RBs comprising the RB pairAt a preset, selected or calculated threshold value (Th)₁) The determined signal power difference.

12. The method of claim 1, wherein step (a) comprises performing the following steps on the PSSCH candidate to determine or identify a potential PSSCH for decoding:

based on having a corresponding number of cyclic shifts (n)_cs) A selected number of different local DMRSs TO make a Timing Offset (TO) estimate TO provide an estimated TO;

performing TO compensation using the estimated TO TO obtain a TO-compensated receive DMRS; and

cyclically associating the TO-compensated receive DMRS and its corresponding local DMRS.

13. The method of claim 12, wherein the step of TO estimation based on a selected number of different local DMRSs comprises processing the ith DMRS in each subframe TO have a kth cyclic shift (n) with the ith received DMRS, respectively_cs) Each potential PSCCH of values is subjected TO a TO estimate, thereby obtaining an estimated TO.

14. The method of claim 13, wherein the cyclic shift (n) is based on the use of (n) for the ith DMRS in each subframe_cs) The estimated TO of value TO compensate for the TO of each potential PSCCH q.

15. The method of claim 14, wherein cyclically associating the TO-compensated received DMRS and its corresponding local DMRS comprises squaring the magnitude of the association result and accumulating the result on the first i received DMRS, thereby resulting in an i DMRS and a k cyclic shift (n) for a q PSCCH subframe location_cs) The real-valued sequence of values is denoted z_i,k,q。

16. The method of claim 15, wherein for the ith DMRS, relativeNormalizing each sequence z on its mean_i,k,qDetermining its peak value(s)_i,k,q) Then a cyclic shift (n) is determined for each value of all possible positions q_cs) The value K, which provides the highest peak s at K1, 2 … K_i,k,qStoring the RB index values q and k and said determined peak value(s)_i,k,q) Associated cyclic shift (n)_cs) Value such that when s_i,k,q>Selected, calculated or preset threshold value (Th)₂) The potential PSCCH is determined to be valid.

17. The method of claim 16, further comprising determining the peak values(s) relative to their respective determined peak values(s)_i,k,q) Ordering all valid potential PSCCHs in descending order to provide M for the ith DMRS_iThe valid potential PSCCH.

18. The method of claim 17, wherein for having M_iThe i-th DMRS of the valid potential PSCCH, by [ [ phi ] ]_i＝f(L,F_i-1) To determine the number of potential PSCCHs desired or needed to be active, where F_i-1Is the accumulated number of valid potential PSCCHs up to the previous DMRS (DMRSi-1) and F _0 ═ 0 and F _1 ═ 0, and L is the required or necessary number of valid potential PSCCHs, by determining whether or not Φ is_i>M_iIf yes, then create a slave phi_iSet C of setting valid potential PSCCHs_i。

19. The method of claim 18, wherein for i ≧ 2, from set C_iAnd C_i-1Is found as set D_iOf a common valid potential PSCCH, where C_iAnd C_i-1Have the same RB position and the same DMRS cyclic shift (n) in the subframe_cs) Value, then, when the number of common valid potential PSCCHs is less than L-F_i-1Then set D will be_iAll of the common valid potential PSCCH entries in,otherwise set D_iL-F in (1)_i-1A common valid potential PSCCH entry with the highest peak, denoted R_iA common valid potential PSCCH for each entry.

20. The method of claim 19, comprising taking the R_iThe entered common valid potential PSCCH is accumulated as F_i＝F_i-1+|R_iL, wherein when F_i≧ L, the desired or required number of potential PSCCHs available is detected to provide selected L PSCCH subsets for decoding, where | -R_iL is R_iThe size of the set.

21. The method of claim 19, wherein for the nth DMRS, R is taken_NThe surrounding potential PSCCH is accumulated into F_N＝F_N-1+│R_NL, wherein when F_N<When L is greater than the set C_NUsing the highest (L-F) of potential PSCCHs from which a common valid PSCCH has been excluded_N) The normalized peaks screen the remaining PSCCH and form L PSCCH subsets for decoding, where R_iL is R_iThe size of the set.

22. The method of claim 12, wherein step (a) comprises performing the following steps on the potential pschs for decoding:

obtaining a normalized energy/power/correlation distribution for the cyclically associated TO-compensated receive DMRS and its corresponding local DMRS; and

for each normalized energy/power/correlation distribution:

identifying a maximum peak of the normalized energy/power/correlation distribution;

-comparing the energy/power/correlation value of the maximum peak with a selected, calculated or preset threshold value (Th)₂) Comparing; and

when the power value of the maximum peak is greater than or equal to the threshold value (Th)₂) Then the potential PSCCH corresponding to the largest peak is taken as the validated potential PSCCH.

23. The method of claim 22, wherein step (c) comprises the steps of:

ranking the energy/power/correlation values of the validated potential PSCCH by energy/power/correlation values from highest to lowest; and

starting from the validated potential PSCCH with the highest energy/power/correlation value, the number L of validated potential PSCCHs is delimited based on their sorted energy/power/correlation values.

24. The method of claim 12, wherein the estimated TO is determined by the formula:

wherein:

y is the received DMRS

l_ncsIs provided with cyclic shift n_csLocal DMRS of

i is the subcarrier index

N_FFTIs the FFT length

(·)^*: is a complex conjugate operation, and

K_sis a configurable interval.

25. The method of claim 2, wherein the step of determining PSCCH candidates in the resource grid comprises performing one or both of the following two sets of steps (a) and (b):

(a) (i) determining a signal power for an RB in the resource grid;

(ii) comparing the signal power obtained on the RB with a selected, calculated or preset threshold (Th)₀) Comparing;

(iii) recognition stationHaving a determined value less than the threshold value (Th)₀) And excluding any or all such RBs from further processing;

(b) (i) selecting a candidate RB pair in the resource grid;

(ii) determining a signal power of each RB in each pair of candidate RBs in the resource grid;

(iii) for each candidate RB pair in the resource grid, determining a difference in signal power between the RBs that make up the RB pair;

(iv) comparing the difference in the obtained signal power between the RBs making up the RB pair with a selected, calculated or preset threshold (Th)₁) Comparing;

(v) identifying that the difference in the obtained signal power between the RBs making up the RB pair is greater than the threshold (Th)₁) And any or all such candidate RB pairs are excluded from further processing.

26. The method according to claim 25, wherein said set of steps (a), to be determined as having a value less than said first threshold value (Th), is performed before said set of steps (b)₀) Is excluded from the selection of candidate RB pairs for processing in said set of steps (b).

27. An apparatus for processing a receive channel signal, the apparatus comprising:

a receiver configured to receive a channel signal, wherein the channel signal comprises a control channel data block of a control channel; and

a signal detection module configured to detect a control channel data block of the control channel, wherein the signal detection module comprises machine readable instructions that have been stored in a memory and executed by a processor to perform the steps of:

(a) for a physical side link control channel (PSCCH) candidate in a resource grid, determining a physical side link control channel (PSCCH) candidate in the resource grid associated with the PSCCH candidateTo determine one or more potential PSCCHs for decoding, each of the one or more potential PSCCHs being cyclically shifted (n) by a Resource Block (RB) position in the resource grid and a respective DMRS_cs) A value to identify;

(b) repeating step (a) for at least one other DMRS in the subframe to determine one or more potential PSCCHs for the at least one other DMRS;

(c) selecting L PSCCH subsets from the potential PSCCH determined by steps (a) and (b); and

(d) shifting (n) the selected L PSCCH subsets and their corresponding cycles_cs) The value can be used in a decoding process of the received channel signal.