WO2012003675A1

WO2012003675A1 - Blind detection method

Info

Publication number: WO2012003675A1
Application number: PCT/CN2010/077822
Authority: WO
Inventors: 吴松; 陈永倩
Original assignee: 新邮通信设备有限公司
Priority date: 2010-07-06
Filing date: 2010-10-18
Publication date: 2012-01-12
Also published as: CN101883369A; CN101883369B

Abstract

A blind detection method is provided by the present invention. The method determines a candidate set of physical downlink control channel (PDCCH) downlink control information (DCI) formats adopted by the blind detection by using a transmission mode allocated to a user equipment (UE) by a network and history scheduling information, and initially determines the number of control channel element (CCE) resources carrying PDCCH by using a measurement result of a channel signal-to-noise ratio and a channel change of two consecutive scheduling processes, thus effectively reducing attempt times of the UE PDCCH blind detection. The present invention enables reducing computing amount and processing complexity of the UE, and reduces UE power consumption and improves system performance.

Description

Blind detection method

Technical field

The invention relates to blind detection technology in a mobile communication system, in particular to long-term evolution

A blind detection method in a (LTE) system. Background of the invention

The LTE system is a broadband mobile communication system. The uplink uses single-carrier frequency division multiple access (SC-FDMA) technology, and the downlink uses orthogonal frequency division (OFDM) multiple access technology. The supported system bandwidth includes 1.4MHz and 3MHz. 5MHz, 10MHz, 15MHz and 20MHz. In the LTE system and the subsequent LTE+ system, in order to maximize the use of resources and improve the system throughput, all the physical resources in the cell are shared and are uniformly scheduled and allocated by the network to the user equipment in the cell (UE). ).

In the LTE system, uplink and downlink resource scheduling are performed through a physical downlink control channel (PDCCH). For the downlink resource allocation, the network side first transmits the related information of the resource allocation to the UE through the PDCCH. After detecting the PDCCH sent to itself, the UE detects the data channel, that is, the physical downlink shared channel (PDSCH) according to the control information in the PDCCH. . For the uplink resource allocation, when the UE needs to send the uplink data, the network side needs to initiate a scheduling request to the network side, and the network side indicates the uplink physical resource allocated to the UE by using the PDCCH, and then the UE can send the uplink data on the allocated physical resource. Therefore, in the LTE system, the physical downlink control channel PDCCH plays a very important role in uplink and downlink resource scheduling. Currently, 10 types of downlink control information (PDCCH DCI, Downlink Control Information) format are defined for scheduling information and different data transmission modes carried by the PDCCH, including DCI Format 0, 1, 1A, 1B, 1C, 1D, 2, 2A. , 3 and 3A, each format carries different control information. Where DCI Format 0 is mainly used for For line scheduling, DCI Format 1, 1A, 1B, 1C, 1D, 2, and 2A are used for downlink scheduling, and DCI Format 3 and 3 A are mainly used to carry uplink power control command words. The physical resources carrying the PDCCH are allocated in units of control channel elements (CCEs, Control Channel Element), each CCE includes 9 resource element groups (REG, Resource Element Group), and each REG includes 4 resource elements (RE , Resource Element;), RE is the smallest resource unit in the LTE system, and each RE represents a time-frequency symbol. As shown in FIG. 1, where one time slot includes one OFDM symbol in the time domain, and one resource block includes ^Λ ^ subcarriers in the frequency domain, therefore, the number of REs included in one resource block in one time slot is AC XW. _s , the number of subcarriers included in the entire system bandwidth is XN.

In order to reduce the control signaling overhead, the LTE system requires the UE to use the blind detection mode when receiving the PDCCH, that is, the UE needs to detect the PDCCH channel currently sent to itself by means of blind detection, and perform downlink data according to the content indicated by the PDCCH channel. The reception or transmission of uplink data. Each PDCCH channel may be carried by one or more consecutive CCEs, and one or more consecutive CCEs carrying the PDCCH constitute a CCE search space. In order to reduce the number of blind detections of the UE, the PDCCH format is generally specified. Each format corresponds to a CCE number that can be used to carry the PDCCH (ie, the CCE search space size). For example, four PDCCH formats are defined in the 3GPP LTE standard. 1, 2, 3, and 3, respectively, the number of CCEs is 1, 2, 4, and 8, that is, in the communication process, according to the information bit length of the DCI and the channel quality during transmission, the network side can The appropriate number of CCEs are selected in the range of 1, 2, 4, and 8 to carry the PDCCH DCI, so that the PDCCH can adapt to the channel change, and meet the requirement that the demodulation error block rate does not exceed 1%. All CCE search spaces that may carry the PDCCH constitute a CCE search space candidate set. For each UE, there are two CCE search spaces that carry the PDCCH channel, that is, a common search space and a UE-specific search space, where the common search space is mainly used for the bearer to notify the UE to receive broadcast and seek. The PDCCH channel of the information, and all UEs are common, and the dedicated search space is allocated for each UE, that is, when the UE is scheduled, the PDCCH channel sent to it may only be used by the common search space or the dedicated search space belonging to it. CCE bearer. For scheduling flexibility, and reducing the number of UE searches, the PDCCH DCI sent by the network to the UE may be carried by using one CCE search space in the CCE search space candidate set. The UE needs to traverse all possible CCE search space candidate sets. The CCE search space, until the PDCCH blind detection is completed, the size of the CCE search space candidate set is configured by the network side. The number of CCEs corresponding to each PDCCH format currently defined in the 3GPP LTE standard and the CCE search

Table 1

Generally, when the UE performs PDCCH blind detection, it first needs to assume the number of CCE resources used for the current PDCCH transmission, and then assumes the DCI format adopted by the PDCCH, performs a decoding attempt, and determines whether the detection is correct by using a CRC check. 2 is a schematic flowchart of a conventional blind detection method. As shown in FIG. 2, the method includes:

Step 201: In each downlink subframe, the UE detects the control region OFDM symbol, and performs demapping, demodulation, and descrambling on the PDCCH channel.

Step 202: The UE selects one of the unselected CCEs from the preset CCE number candidate set. The number is taken as the current CCE search space size S.

Step 203: In the preset CCE search space candidate set, select a CCE search space of size S and not selected as the current CCE search space.

Specifically, in this step, a method of sequential selection is implemented when selecting a CCE search space. That is, the multiple CCE search spaces included in the CCE search space candidate set of the UE are generally continuous, and when the UE searches, the first search space (S consecutive CCEs) is blindly detected from the start position. If a CCE search space fails, the next CCE search space is detected in turn. For example, if the CCE search space candidate set includes 4 CCE search spaces, and the size N of each CCE search space is 4, the UE first detects the first CCE search space (composed of the 1st to 4th CCEs), if If it fails, the second CCE search space is selected as the current CCE search space for detection (composed of the 5th to 8th CCEs), and so on.

Steps 204 to 208: Select one PDCCH DCI format from the preset PDCCH DCI format set, and use the current CCE search space to perform decoding and CRC check on the selected PDCCH DCI format, if the CRC check succeeds If the blind detection succeeds, the blind detection process ends. Otherwise, an undetected PDCCH DCI format is selected, and the decoding and verification are continued; all possible PDCCH DCI formats are traversed, and if the CRC check is incorrect, the execution is performed. Step 209.

Here, the PDCCH DCI format set will include all PDCCH DCI formats that may be employed by the network side.

Step 209: Determine whether all CCE search spaces of size S are selected in the CCE search candidate set. If yes, go to step 210, otherwise go to step 203.

Step 210: Determine whether there is one unselected number of CCEs in the preset CCE number candidate set. If yes, go to step 202, otherwise exit the blind detection process.

If the blind detection process is exited in this step, the current network may not be given to the UE. The PDCCH is transmitted, or the PDCCH fails to be detected due to network quality or other reasons.

It can be seen from the above process that the existing blind detection method needs to be continuously tried, especially in the limit case, all the CCE numbers and the PDCCH DCI format need to be tried. Therefore, the method has a large processing amount, high complexity, and consumption. The duration and the problems that are not conducive to the power saving of the UE. Summary of the invention

In view of this, the main object of the present invention is to provide a blind detection method, which can effectively reduce the processing complexity and power consumption of the UE.

In order to achieve the above object, the technical solution proposed by the present invention is:

A blind detection method, when the last two effective scheduling intervals of the user equipment (UE) are within a preset correlation time T, the method includes the following steps:

XI) in each downlink receiving subframe, the UE performs detection, demodulation, and descrambling of a control symbol where a physical downlink control channel (PDCCH) is located;

Determining, by the UE, the PDCCH DCI format candidate set adopted by the network side of the current scheduling subframe according to the downlink transmission mode adopted by the previous scheduling subframe adjacent to the current scheduling subframe in the preset correlation time T, and according to The PDCCH DCI format of the PDCCH DCI format candidate set is sorted by a preset ordering principle, and the PDCCH DCI format corresponding to the downlink transmission mode adopted by the previous scheduling subframe is preferentially ranked in front of the queue, where The PDCCH DCI format adopted by the previous scheduling subframe is ranked first in the queue;

X3) the UE determines a control channel element (CCE) that may be used when receiving the PDCCH according to a signal-to-noise ratio (SNR) measurement result of a most recent secondary feedback channel quality indicator (CQI) in the latest or the relevant time T The number of CCEs used as the current CCE search space is N;

X4) The UE selects a CCE of size N in a preset search space candidate set Search space as the current CCE search space;

X5) the UE uses the current CCE search space to sequentially detect, decode, and CRC the sorted PDCCH DCI format until the CRC check succeeds; if the CRC check fails Go to step X6, otherwise, exit the blind detection method;

X6) The UE determines whether there is a CCE search space that is not selected and the number of CCEs is N in the CCE search space candidate set, and if yes, selects a CCE search space that is not selected and has a CCE number of N as the current CCE search space, perform step X5; otherwise, perform step X7;

X7) The UE determines whether there is an unselected number of CCEs in the preset number of CCEs, and if yes, selects an unselected number of CCEs as the number of CCEs of the current CCE search space, and performs steps. X4; Otherwise, the blind detection method ends.

In summary, the blind detection method proposed by the present invention determines the PDCCH DCI format candidate set for blind detection by using the network configuration to the UE transmission mode and historical scheduling information, and uses the channel SINR/SNR measurement result and the adjacent two times. The channel change during scheduling initially determines the number of CCE resources that carry the PDCCH, which greatly reduces the number of attempts of the UE PDCCH blind detection, and can reduce the calculation amount and processing complexity of the UE, reduce the power consumption of the UE, and improve system performance. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an existing downlink resource element;

2 is a schematic flow chart of a conventional blind detection method;

3 is a schematic flowchart of blind detection when the last two effective scheduling intervals of the UE do not exceed the relevant time T according to an embodiment of the present invention;

4 is a schematic flowchart of a UE feeding back a CQI and receiving a PDCCH in an existing system; FIG. 5 is a schematic flowchart of blind detection when a UE's last two effective scheduling intervals are greater than a correlation time T or a UE first receives a PDCCH signal according to another embodiment of the present invention. Mode for carrying out the invention

The present invention will be further described in detail below with reference to the drawings and specific embodiments.

The core idea of the present invention is: determining the PDCCH DCI format blind detection candidate set by using the network configuration to the UE transmission mode and historical scheduling information, and initially determining the bearer PDCCH by using the channel SINR/SNR measurement and the channel change in the adjacent two schedulings. The range of the number of CCE resources can greatly reduce the number of UE PDCCH blind detection attempts, reduce the computational complexity and processing complexity of the UE, reduce UE power consumption, and improve system performance.

FIG. 3 is a schematic diagram of a blind detection process according to an embodiment of the present invention. The embodiment provides a transmission mode and historical scheduling using a network configuration to a UE when the last two effective scheduling intervals of the UE are within a preset correlation time T. A method for blind detection of information, as shown in FIG. 3, the embodiment includes:

Step 301: In each downlink receiving subframe, the UE performs detection, demodulation, and descrambling of a control symbol where a physical downlink control channel (PDCCH) is located. Step 302: The UE determines, according to a downlink transmission mode that is used by the previous scheduling subframe that is adjacent to the current scheduling subframe in the preset correlation time T, the PDCCH DCI format candidate set used by the network side of the current scheduling subframe, and The PDCCH DCI format in the PDCCH DCI format candidate set is sorted according to a preset ordering principle, and the PDCCH DCI format corresponding to the downlink transmission mode adopted by the previous scheduling subframe is preferentially ranked in front of the queue. The PDCCH DCI format adopted by the previous scheduling subframe is ranked first in the queue. It should be noted here that the "scheduling subframe" here is different from the previous "downlink receiving subframe" concept: in the LTE system, the network side sends a scheduling command to the scheduled UE in the downlink receiving subframe, for the For the scheduled UE, the downlink receiving subframe is a "scheduling subframe", that is, the "scheduling subframe" is for a certain UE, and only the UE correctly detects the network in a certain downlink receiving subframe. When the scheduling command is used, the downlink receiving subframe is the scheduling subframe of the UE. Appropriate values are set by the UE's moving speed and channel change in the application. For example, when the UE motion speed is high, the correlation time T can be set smaller, and when the UE motion speed is low, the correlation time T can be set larger.

In the LTE system, in order to distinguish different UEs, it is convenient for the network side to schedule the UE, and a set of Radio Network Temporary Identifiers (RNTIs) are defined as temporary IDs, which are allocated to UEs in the cell for use. The RNTI can be classified into a cell RNTI (C-RNTI, Cell RNTI), a semi-persistent scheduling C-RNTI (SPS C-RNTI, Semi-Persistent Scheduling C-RNTI), and a system according to the type of data transmitted and the state of the UE. Information RNTI (SI-RNTI, System Information RNTI), paging RNTI (P-RNTI, Paging RNTI), and temporary C-RNTI (TC-RNTI, Temporary C-RNTI) „ When the PDCCH is transmitted on the network side, it will be selected according to the situation. The corresponding RNTI is used to scramble the CRC check value of the control information carried by the PDCCH channel, so that when receiving the PDCCH, the UE performs PDCCH detection by using the RNTI indicated by the upper layer to determine whether the current PDCCH channel is sent to itself. When the system allocates C-RNTI, TC-RNTI or SPS C-RNTI to the UE in the cell, the ID assigned by each UE is different, and for SI-RNTI, P-RNTI and RA-RNTI, it is a cell. The UE is shared within use.

It should be noted that, in the current 3GPP LTE standard, when the UE is in the connected state, the upper layer configures the UE to receive the PDCCH that is scrambled by the C-RNTI cyclic check code (CRC code). At the time of the multi-antenna transmission and reception mode adopted by the UE, seven transmission modes are defined. In each transmission mode, there is a corresponding PDCCH DCI format, a specific transmission mode, and a PDCCH DCI format that can be adopted in each mode, such as Table 2 shows. In addition, when the UE is in the connected state, the network layer may adopt a semi-persistent scheduling mode for the UE. In this case, the upper layer configures the UE to receive the PDCCH that is scrambled by the SPS C-RNTI, and in this case also defines 7 A transmission mode, each mode has a corresponding PDCCH DCI format, as shown in Table 2a.

DCI Format UE dedicated search space multi-user MIMO

ID

Mode 6 DCI Format Common and UE-specific search Send diversity

1A cable space

DCI Format UE dedicated search space closed loop space-time complex IB under single transport layer

Mode 7 DCI Format Common and UE-specific search single antenna port transmission or transmit diversity

1A cable space

DCI Format 1 UE-specific search space Single antenna port transmission, port 5 Table 2

In addition to the above two cases, in the current 3GPP LTE protocol specification, for different receiving states of the UE or data types to be received, such as receiving broadcast data, paging data, or resource allocation indication on the network side when receiving random access, The PDCCH DCI format that may be used is also defined for the LTE specifications to facilitate the UE to perform detection. When the UE needs to receive the broadcast information, the DCI format corresponding to the PDCCH that the upper layer configures the UE to receive the scrambling CRC by the SI-RNTI is as shown in Table 2b. When the UE needs to receive the paging information, the upper layer configures the UE to receive the P-RNTI. The DCI format corresponding to the PDCCH of the CRC is as shown in Table 2b. When the UE receives the resource allocation indication of the network side during the random access, the high-level configuration UE receives the DCI format corresponding to the PDCCH that is scrambled by the RA-RNTI. 2b is shown. In addition, in some cases, the upper layer configures the UE to receive the PDCCH that is scrambled by the temporary C-RNTI (TC-RNTI), and the corresponding DCI format is as shown in Table 2c. Transmission mode DCI format search space description mode 1 DCI Format public and UE dedicated search antenna port transmission, port O

1A cable space

DCI Format UE dedicated search space single antenna port transmission, port O 1

Mode 2 DCI Format Common and UE-specific search Send diversity

1A cable space

DCI Format UE dedicated search space Send diversity 1

Mode 3 DCI Format Common and UE-specific search Send diversity

1A cable space

DCI Format UE dedicated search space Send diversity 2A

Mode 4 DCI Format Common and UE-specific search Send diversity

1A cable space

DCI Format UE dedicated search space Send diversity 2

Mode 5 DCI Format Common and UE-specific search Send diversity

1A cable space

Mode 6 DCI Format Common and UE-specific search Send diversity

1A cable space

Mode 7 DCI Format Common and UE-specific search single antenna port transmission, port 5

1A cable space

DCI Format UE dedicated search space Single antenna port transmission, port 5 1

Table 2a

Table 2b DCI Format search space description

DCI Format Common and UE-specific If the number of antenna ports for transmitting PBCH is 1, the 1A search space is used. Single antenna port: port O; otherwise, transmit diversity

DCI Format 1 UE-specific search empty If there is one antenna port for transmitting PBCH, the single-antenna port is used: port O; otherwise, the transmit diversity table 2c

In this step, when the candidate set of the PDCCH DCI format is specifically determined, the following method may be implemented:

Determining, by the UE, whether the currently used downlink transmission mode is the same as the downlink transmission mode used by the previous scheduling subframe, and if yes, determining that the PDCCH DCI format candidate set includes the downlink used by the previous scheduling subframe All PDCCH DCI formats corresponding to the transmission mode; otherwise, determining that the PDCCH DCI format candidate set includes all PDCCH DCI formats corresponding to the currently adopted downlink transmission mode and corresponding to the downlink transmission mode adopted by the previous scheduling subframe All PDCCH DCI formats.

It can be seen from Table 2 that a downlink transmission mode may correspond to multiple PDCCH DCI formats. It can be seen that, in practical applications, the PDCCH DCI format candidate set determined in this step may include multiple PDCCH DCI formats. In this case, in order to reduce the number of PDCCH DCI formats that are attempted during detection, in this step, the PDCCH DCI formats in the PDCCH DCI format candidate set are sorted in descending order of the usage probability of each PDCCH DCI format. The PDCCH DCI format with a high probability of use is placed in front of the queue.

Generally, in two adjacent scheduling, the transmission mode of the same UE is less likely to change, and the possibility of adopting the PDCCH DCI format change is also small. Therefore, in this step, the PDCCH DCI format corresponding to the downlink transmission mode adopted by the previous scheduling subframe is preferentially ranked in front of the queue, where the PDCCH DCI format adopted by the previous scheduling subframe is Ranked first in the queue. Specifically, in the PDCCH DCI format candidate set, the PDCCH DCI format adopted in the last network scheduling is taken as the highest priority. In the first place, if there are other available PDCCH DCI formats in the transmission mode, the PDCCH DCI formats are sequentially arranged after the highest priority PDCCH DCI format. For example: Without loss of generality, let the priority be defined as 0, 1, 2, ... from high to low. The PDCCH DCI format available in a certain transmission mode is DCI Format#0, DCI Format#l , DCI Format#2, if the DCI format used in the previous scheduling is DCI Format#1, when determining the PDCCH DCI format candidate set, DCI Format#1 is ranked as the highest priority (priority level is 0) in the DCI format candidate. At the forefront of the set, for DCI Format#0 and DCI Format#2, the priority can be determined randomly, after DCI Format#l, for example, DCI Format#0 can be assumed to have priority 1, DCI Format#2 The priority is 2, so that the preliminary DCI format candidate set is (DCI Format#l, DCI Format#0, DCI Format#2). In addition, during downlink data transmission, the transmission mode of the same UE may change due to channel environment changes or network side scheduling. Therefore, when determining the PDCCH DCI format blind detection candidate set, other transmissions that the UE may use are needed. The PDCCH DCI format corresponding to the mode is included in the PDCCH DCI format candidate set, and the PDCCH DCI format is ranked after the last DCI format in the determined DCI format candidate set. If the new transmission mode includes multiple DCI formats, the DCI formats are The order may be randomly determined, but may not be ranked in front of the PDCCH DCI format of the determined DCI format blind detection candidate set, unless one or more PDCCH DCI formats are in the determined PDCCH DCI in the PDCCH DCI format included in the new transmission mode. The format candidate set already exists, and these PDCCH DCI formats are processed according to the determined arrangement of the PDCCH DCI format candidate set. For example: Assume that the DCI format candidate set determined by the original transmission mode is (DCI Format#l, DCI Format#0, DCI Format#2), and the new transmission mode corresponding to the available DCI format after the transmission mode is changed includes DCI Format #1, DCI. Format #3, DCI Format#4, the DCI format candidate set after adding a new DCI format is (DCI Format#l, DCI Format#0, DCI Format#2, DCI Format#3, DCI Format#4), where DCI Format#l due to The original DCI blind detection candidate set already exists, so the original priority remains unchanged, and DCI Format#3 and DCI Format#4 are not in the blind detection candidate set, and the DCI format candidate set needs to be added, and the priority is the lowest priority from the candidate set. After the DCI Format #2 of the level is started, the priority levels are 3 and 4. If there are multiple possibilities for the change of the transmission mode, the DCI formats corresponding to all possible transmission modes need to be added to the DCI format candidate set. The joining method is the same as described above. For example, if the transmission mode 4 may be changed to the transmission mode 6, or may be changed to the mode 3, the DCI formats corresponding to the transmission mode 6 and the transmission mode 3 need to be added to the DCI format blind detection candidate set.

Step 303: The UE determines the number of CCEs that may be used when receiving the PDCCH according to the SNR measurement result of the last time or the latest secondary feedback channel quality indicator (CQI) in the relevant time T, and uses the _Np as the Number of CCEs in the current CCE search space

In this step, the current downlink receiving subframe is currently.

It should be noted that in the communication process, the UE receives the downlink common pilot signal, performs SNR/SINR measurement, and maps it to the CQI feedback to the network side, and the network side refers to the CQI measurement result to perform user resource allocation and scheduling. In addition, when the network side allocates the CCE resources used by the PDCCH, it also refers to the CQI measurement value reported by the UE. Therefore, the UE may store the SINR/SNR corresponding to the measured CQI according to the CQI and the PDCCH receiving relationship of the measurement feedback, and establish a mapping relationship with the CCE resource used when the PDCCH blind detection succeeds according to the timing relationship. PDCCH blind detection provides a reference.

4 is a schematic flowchart of a UE feeding back a CQI and receiving a PDCCH in an existing system. As shown in FIG. 4, in the communication process, the UE measures the CQI in the nth subframe and feeds back to the network side base station (eNB), so that the corresponding SNR is SNR _n , and the eNB refers to the CQI value, at the nth. The +k (k>0) subframe schedules the UE, and adopts A CCEs to carry the PDCCH. The UE successfully detects the PDCCH blindly in the n+k subframe, and is set in the n+i (i>k) subframe. , UE measured again The CQI is measured and reported to the eNB, and the corresponding SNR is SNR _n+i . In the n+m (m>i) subframe, the eNB refers to the CQI reported by the UE in the n+i subframe to schedule the UE. The B CCEs are used to carry the PDCCH. The UE needs to infer that the eNB sends o P according to the measured SNR change.

The number of CCEs that may be adopted in the PDCCH, thereby blindly detecting the PDCCH transmitted by the eNB in the n+m subframe. Based on the above idea, specifically, in this step, it may be determined according to the SNR measurement result when the CQI is most recently fed back in the relevant time T, including:

= SNR _{n -} SNR _{n + i} , calculating a difference ^ of the SNR measurement results of the last two feedback CQIs of the UE during the correlation time T, where "and " are the last two feedback CQIs respectively The subframe number of the time, w<w + ;

Querying a preset correspondence table between AWR and CCE relative offsets, and obtaining a relative offset of the number of CCEs corresponding to the ASNR; l + j<

According to P 0<l + j<P , it is determined that the N _{p is} in the CCE l + j>P number set: {Λ^. , Λ^, ..... , N _P }, the element subscript ρ , 0<p<P; where P is the difference between the number of elements in S and 1 and / is the current most recent time of the UE The number of CCEs used in the successful blind detection is subscripted in the element in the S;

According to the p, the number of sets from the CCE {N. , N ..... , N _P } is obtained. In the above determined method, the correspondence table between the MM? and the CCE relative offset may be constructed in the manner of Table 3:

A^ R range ( _dB ) relative offset

ASNR < Th ₀ -P

Th ₀ < ASNR < Th _x - (Pl )

T < ASNR < Th ₂ - (P-2) Th _p _ _x < ASNR < Th _p 0

Th _p < ASNR < Th _p+1 1

Th _2P < ASNR < Th _2P+1 P- l

Th _2P+1 < ASNR P

table 3

The threshold value 73⁄4 ( 0 ≤ ≤ 2« - 1 ) in Table 3 can be determined according to the simulation, that is, for different channel environments, for a certain PDCCH DCI format, by using a different number of CCE resources for carrying Demodulate the signal to noise ratio. Considering the measurement error and the difference between the actual channel environment and the simulation, the actual threshold value needs to be appropriately offset based on the simulation. In the actual simulation, the demodulation SNR requirement of the PDCCH DCI format under the condition of additive white Gaussian noise (AWGN) and different CCEs can be directly simulated, so that the M layer and the CCE are established according to the SNR obtained by these simulations. In the actual correspondence process, the UE obtains the SNR value of the measured SNR value through the signal-to-noise ratio mapping method, such as the exponential effective signal-to-noise ratio mapping method EESM, to obtain the SNR under the corresponding AWGN channel, so that the look-up table is relatively biased. Transfer amount. Here, the specific simulation method is known to those skilled in the art, and details are not described herein again.

The method for determining the foregoing is specifically described by using the 3GPP R8 LTE as an example. The number of CCEs carrying the PDCCH is 1, 2, 4, 8, that is, the CCE number set {Λ^. _{, Λ ^, ....., Ν Ρ} , is S: {1, 2, 4 , 8}, where Ρ = 3, the MM can be assumed with relative offset CCE number correspondence table as shown in Table? 4 shows:

- 3 < ASNR < 3 0

3≤ ASNR < 6 1

6 ≤ ASNR < 9 2

9 < ASNR 3

Table 4

Assume that the number of CCEs used in the n+k subframe is N. =l, corresponding, /=0, ASNR is -5άΒ, query table 4 knows that the corresponding relative offset =-l, then /+ =0-l=-l, since /+ is less than 0, take 0, That is, the number of CCEs used this time is the same as the last time, which is N. = l CCE; if R is 5dB, then j = l, i + j = l, the number of CCEs that may be used this time is NF2; if ^ is 10dB, then j = 3, i + j = 3, this the number of times may be used as CCE N _p N ₃ = 8 th CCE.

In practical applications, it may also be determined according to the SNR measurement result when the CQI is last feedbacked in the relevant time T. The specific method may be:

The UE queries the preset CCE-PDCCH DCI-SNR correspondence table, and obtains the number of CCEs corresponding to the SNR measurement result when the UE currently reports the CQI, and determines the number of CCEs corresponding to the SNR measurement result as the current receiving. The number of CCEs that may be used in the PDCCH.

The CCE-PDCCH DCI-SNR correspondence table includes various CCE numbers corresponding to obtain a demodulation signal-to-noise ratio SNR requirement of different PDCCH DCI formats in different CCE resource configurations by simulation, so that the CCE can be established. PDCCH DCI-SNR correspondence table.

Step 304: The UE selects a CCE search space of size N as the current CCE search space in the preset search space candidate set.

Specifically, when performing the selection, any CCE search space of size N may be selected from the start position of the search space candidate set, or may be selected from the search. The first CCE exploration space of size N starting from the beginning of the spatial candidate set.

Step 305-309: The UE performs detection, decoding, and CRC check on the sorted PDCCH DCI format in sequence according to the current CCE search space, until the CRC check succeeds; If the test fails, step 310 is performed, otherwise, the blind detection method is exited.

The method for detecting, decoding, and CRC is performed on the PDCCH DCI format, and the specific method is known to those skilled in the art, and details are not described herein.

Here, since the sorted PDCCH DCI formats are arranged in descending order according to the usage probability, in this step, the PDCCH DCI format with the highest usage probability is preferentially detected, decoded, and CRC-checked. The accuracy of the first attempt detection is effectively improved, thereby reducing the number of PDCCH DCI formats that need to be tried, and effectively reducing the complexity and power consumption of the UE processing.

Step 310: The UE determines whether there is a CCE search space that is not selected and the number of CCEs is N in the preset CCE search space candidate set. If yes, step 311 is performed; otherwise, step 312 is performed.

When all the CCE search spaces in the CCE search space candidate set are detected, the DCI blind detection fails. The number of CCEs detected is incorrect. Step 312 is required to select the next type. If the number of CCEs whose number of CCEs is N is CCE search space, if there are still CCE search spaces whose number of CCEs is not N, then go to step 311 to trigger CCE search for the number of CCEs is N. Space is tested.

Step 311: The UE selects a CCE search space that is not selected and has a CCE number of N as the current CCE search space, and proceeds to step 305.

Here, the selection may be implemented in a random selection manner, or may be implemented in a sequential selection manner, and may be determined by a person skilled in the art according to actual needs.

Step 312: The UE determines whether there is a preset number of CCEs that are not selected. The number of CCEs, if yes, step 313 is performed; otherwise, the blind detection process is ended. In this step, if it is determined that the number of all CCEs in the CCE number set has been selected, it indicates that the network side does not schedule the UE in the current subframe, or the PDCCH detection fails due to other reasons, so the blind detection will end. When it is determined that there are still CCEs in the CCE number set, the number of unselected CCEs is selected as the space size of the current CCE search space in the subsequent step, that is, the CCE search space includes The number of CCEs is N, and then proceeds to step 304 to detect the CCE search space determined by the number of CCEs.

Step 313: Select a number of CCEs that are not selected as the number of CCEs of the current CCE search space, and perform step 304.

Here, the method of selecting a number of unselected CCEs as the number of CCEs of the current CCE search space may be:

When the SNR measurement result of the UE's most recent secondary feedback CQI is increasing, the number of CCEs that are not selected is selected as the number of CCEs of the current CCE search space according to the principle of decreasing the number of CCEs.

When the SNR measurement result of the UE's recent double feedback CQI is in a downward trend, the number of CCEs that are not selected is selected as the number of CCEs of the current CCE search space according to the principle of increasing the number of CCEs.

In the above method, the number of other CCEs in the CCE number set is selected based on the first selected number of CCEs _Np , and is preferentially selected by referring to the measured SNR change trend. Since the network side configures the CCE according to the SNR change trend, selecting the next CCE number by referring to the measured SNR change trend can improve the success rate of selecting the correct number of CCEs, and reducing the number of attempts during detection, thereby reducing the UE. The complexity of side processing. Assuming that the SNR measured by the n+i subframe is lower than the SNR measured by the nth subframe, it indicates that the number of CCE resources needs to be increased, pt=p+l, otherwise, /7=ρ-1, if 0≤pt≤P, then Take N in the CCE number set S as CCE Number, and assign the N _pi value to N, ? N= N _pt , for example: If 4 CCE blind detection fails, if the SNR trend is smaller, MNR >0, then the number of possible CCE resources is 8, if the SNR trend becomes larger ( Δ^Μ? <0), the number of CCE resources replaced is two.

The above method determines the PDCCH DCI format blind detection candidate set by using the transmission mode and the historical scheduling information of the network configuration to the UE in the relevant time T, and initially determines the bearer by using the channel SINR/SNR measurement and the channel change in the adjacent two schedulings. The number of CCE resources of the PDCCH greatly reduces the number of attempts of the UE PDCCH blind detection, which can reduce the calculation amount and processing complexity of the UE, reduce the power consumption of the UE, and improve system performance. In the actual communication process, there may be a time when the UE is in the discontinuous reception (DRX) state, and the two consecutive effective scheduling times exceed the configured correlation time T, so that when the UE performs the PDCCH blind detection The information about the last successful detection of the PDCCH may not be completely used as a reference for the current detection, or the UE receives the PDCCH for the first time, and no history detection information is available for reference. In the above case, the last two effective scheduling intervals of the UE When the correlation time T is greater than the correlation time T, or when the UE receives the PDCCH signal for the first time, as shown in FIG. 5, the following steps may be used to implement blind detection of the PDCCH.

Step 501: A CCE-PDCCH DCI-SNR correspondence table is established in advance by using a simulation, and is stored in the UE, where the UE determines a PDCCH DCI candidate set according to a downlink transmission mode configured by a high layer or a data type that needs to be received currently; The CCE-PDCCH DCI-SNR correspondence table includes PDCCH DCI formats corresponding to the number of various CCEs and SNR values corresponding to the number of various CCEs.

Here, the PDCCH DCI candidate set is determined according to the downlink transmission mode of the high layer configuration: Query Table 2/Table 2a/Table 2b/Table 2c, the PDCCH DCI format corresponding to the downlink transmission mode, and the PDCCH DCI format is used as the PDCCH DCI Selection.

Determining the PDCCH DCI candidate set according to the type of data currently required to be received: According to the data type currently required to be received, the query table 2/table 2a/table 2b/table 2c may be used. The PDCCH DCI format uses these PDCCH DCI formats as PDCCH DCI candidate sets. Here, the specific method for determining the CCE search space corresponding to the data type is known to those skilled in the art, and details are not described herein again.

For example, assuming that the UE currently needs to receive broadcast information or paging information carried by the PDSCH, according to Table 2b, it may be determined that the search space of the UE is a common search space, and the DCI format is PDCCH DCI Format 1A or 1C; - RNTI scrambles the PDCCH of the CRC, and the corresponding data transmission mode is mode 4. According to Table 2, the corresponding DCI format blind detection candidate set is (DCI Format 1A, DCI Format 2).

In this step, the method for constructing the CCE-PDCCH DCI-SNR correspondence table is the same as the method in step 303, and details are not described herein again.

Step 502: The UE selects one PDCCH DCI format from the determined PDCCH DCI format candidate set as the current PDCCH DCI format according to the SNR measurement result when the CQI is reported last time.

Step 503: The UE queries the CCE-PDCCH DCI-SNR correspondence table, and obtains the number of CCEs corresponding to the current PDCCH DCI format under the SNR measurement result, and uses the obtained CCE number as the current CCE search space. The number of CCEs is N.

Step 504: The UE selects a CCE search space of size N from the preset CCE search space candidate set as the current CCE search space.

Step 505: The UE performs detection, decoding, and CRC check on the current PDCCH DCI format based on the current CCE search space.

Step 506: Determine whether the CRC check is correct. If yes, exit the blind detection process; otherwise, go to step 507.

Here, if the CRC check is successful, the PDCCH DCI detection is successful, so the blind detection process is exited.

Step 507: Determine whether all CCE search spaces with N number of CCEs have been If yes, go to step 509, otherwise, go to step 508.

When the CRC check based on all the CCE search spaces with the number of CCEs is N, the current N value is not the correct CCE search space size. Therefore, step 509 is performed to select a new CCE search space size. try.

Step 508: Select a CCE search space with a number of CCEs N and not selected as the current CCE search space from the CCE search space candidate set, and perform step 505 again.

Step 509: The UE determines whether there is an unselected number of CCEs in the preset CCE number set. If yes, step 510 is performed; otherwise, step 512 is performed.

The preset CCE number set may be a CCE number set corresponding to a common search space or a dedicated search space.

Step 510: The UE selects an unselected number of CCEs as the number of CCEs of the current CCE search space, and performs step 504.

Step 511: The UE determines whether there is an unselected PDCCH DCI format in the PDCCH DCI format candidate set. If yes, step 512 is performed; otherwise, the blind detection process is exited.

Step 512: Select an unselected PDCCH DCI format as the current PDCCH DCI format, and perform step 503.

In conclusion, the above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications, equivalents, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claim

A blind detection method, characterized in that, when the last two effective scheduling intervals of the user equipment (UE) are within a preset correlation time T, the method comprises the following steps:

X3) the UE determines a control channel element (CCE) that may be used when receiving the PDCCH according to a signal-to-noise ratio (SNR) measurement result of a most recent secondary feedback channel quality indicator (CQI) in the latest or the relevant time T the number N _p as the current number of CCE CCE search space N;

X4) the UE selects a CCE search space of size N as the current CCE search space in the preset search space candidate set;

X6) The UE determines whether there is a CCE search space that is not selected and the number of CCEs is N in the CCE search space candidate set, and if yes, selects one unselected and CCE The CCE search space with the number N is used as the current CCE search space, and step X5 is performed; otherwise, step X7 is performed;

X7) The UE determines whether there is an unselected CCE in the preset number of CCEs

^ o P

If yes, select an unselected number of CCEs as the number of CCEs in the current CCE search space, and perform step X4; otherwise, end the blind detection method.

2. The method of claim 1, wherein the determining the number of CCE N _p may be used as the current reception PDCCH:

Querying a preset AWR and CCE relative offset correspondence table, and obtaining a relative offset C of the CCE corresponding to the ASNR;

l + j<

According to p 0<l + j<P , the element subscript ρ of the N _p in the CCE l + j>P number set ^{Λ^, Λ^, ....., N _P } is determined. , Q<p<P ; where is the difference between the number of elements in ^ and 1 , / is the element index of the number of CCEs used in the current blind detection of the UE in the S;

According to the p, the number of sets from the CCE {N. , N ..... , N _P } is obtained.

The method according to claim 1, wherein the determining the number of CCEs that may be used when receiving the PDCCH is:

The UE queries the preset CCE-PDCCH DCI-SNR correspondence table, and obtains the number of CCEs corresponding to the SNR measurement result when the UE last reported the CQI, and determines the number of CCEs corresponding to the SNR measurement result as The number of CCEs that may be used when receiving the PDCCH; the CCE-PDCCH DCI-SNR correspondence table includes the number of CCEs

The method according to claim 1, wherein the selecting the number of unselected CCEs as the number of CCEs of the current CCE search space is:

When the SNR measurement result of the UE's most recent secondary feedback CQI is increasing, it is preferred to select an unselected CCE number as the current one according to the principle of decreasing CCE number.

Number of CCEs in the CCE search space N

When the SNR measurement result of the UE's most recent secondary feedback CQI is in a downward trend, the number of unselected CCEs is selected as the current one according to the principle of increasing the number of CCEs.

The number of CCEs in the CCE search space is N.

The method according to claim 1, wherein when the last two active scheduling time intervals of the UE are greater than the correlation time T, or the UE receives the PDCCH signal for the first time, the method further includes:

The CCE-PDCCH DCI-SNR correspondence table is set up in advance by the UE, and is stored in the UE, and the UE determines the PDCCH DCI candidate set according to the downlink transmission mode configured by the high layer or the data type that needs to be received currently; - PDCCH DCI-SNR correspondence table includes PDCCH DCI format corresponding to the number of various CCEs and SNR value corresponding to the number of various CCEs;

Y2) the UE selects one PDCCH DCI format from the determined PDCCH DCI format candidate set according to the SNR measurement result when the CQI is reported last time;

Y3) The UE queries the CCE-PDCCH DCI-SNR correspondence table, and obtains the number of CCEs corresponding to the current PDCCH DCI format under the SNR measurement result, and uses the obtained CCE number as the CCE of the current CCE search space. Number N

Y4) the UE selects a CCE search space of size N from the preset CCE search space candidate set as the current CCE search space;

Y5) the UE is based on the current CCE search space, for the current PDCCH DCI Format for detection, decoding and CRC verification;

Y6) determining whether the CRC check is correct, and if yes, exiting the blind detection method; otherwise, performing step Y7;

Y7) judging whether all CCE search spaces with N number of CCEs have been selected, if yes, executing step Y9, otherwise, performing step Y8;

Y8) selecting, from the CCE search space candidate set, a CCE search space with a number of CCEs that is not selected as the current CCE search space, and performing step Y5 again;

Y9) The UE determines whether there is a number of unselected CCEs in the preset number of CCEs, and if yes, performs step Y10; otherwise, performs step Y11;

Y10) The UE selects an unselected number of CCEs as the number of CCEs of the current CCE search space, and performs step Y4;

Y11) The UE determines whether there is an unselected PDCCH DCI format in the PDCCH DCI format candidate set, and if yes, selects an unselected PDCCH DCI format as the current PDCCH DCI format, and performs step Y3; otherwise, exits the A blind detection method.

The method according to claim 1, wherein the determining, in the step X2, the candidate set of the PDCCH DCI format adopted by the network side of the current scheduling subframe is:

Determining, by the UE, whether the currently used downlink transmission mode is the same as the downlink transmission mode used by the previous scheduling subframe, and if yes, determining that the PDCCH DCI format candidate set includes the last scheduling subframe. All PDCCH DCI formats corresponding to the downlink transmission mode; otherwise, determining that the PDCCH DCI format candidate set includes all PDCCH DCI formats corresponding to the currently adopted downlink transmission mode and the downlink transmission mode adopted by the previous scheduling subframe All PDCCH DCI formats.