A method and system for blind detection of a physical downlink control channel of a 5G NR system

Abstract

The present application relates to the technical field of 5G NR channel detection, and particularly relates to a physical downlink control channel blind detection method and system of a 5G NR system, comprising: obtaining a plurality of candidate sets to be detected in a search space; selecting a candidate set; in a channel estimation process, extracting a demodulation reference signal from the candidate set, performing correlation calculation on the demodulation reference signal and a local reference sequence to obtain a correlation result, and determining whether the candidate set contains a physical downlink control channel; if yes, subsequent processing is performed; if no, a new candidate set is obtained. The beneficial effects are that, by performing correlation calculation on the demodulation reference signal and the local reference sequence in the channel estimation process, it is determined whether the candidate set represented by the demodulation reference signal contains a physical downlink control channel, and the candidate set that is impossible to contain a physical downlink control channel is removed, thereby reducing the number of candidate sets that need to be blindly detected in the subsequent blind detection step, and improving the blind detection efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of 5G NR channel detection technology, and particularly relates to a physical downlink control channel blind detection method and system of a 5G NR system. BACKGROUND

[0002] 5G NR (New Radio) is a global 5G standard based on OFDM (Orthogonal Frequency Division Multiplexing) air interface design. In the 5G NR system, the frequency domain scheduling range information and the time domain OFDM symbol number information of the PDCCH (Physical Downlink Control Channel) are encapsulated in the CORESET (Control Resource Set), and the time domain starting symbol information and the detection period information are encapsulated in the SearchSpace (Search Space). At this time, the user equipment can only know that the PDCCH will be sent within the RB (Resource Block) range of the CORESET, but cannot determine which RBs are sent on. Therefore, after the PDCCH channel determines the physical resource information, the search space type (CSS or USS) and other information, the user equipment will search the PDCCH on the CORESET according to different RNTI types in different search spaces. Since the user equipment does not explicitly know the time-frequency location of the PDCCH, it can only continue to demodulate the candidate set of the PDCCH, so this process is called blind detection of the PDCCH.

[0003] In the prior art, the number of PDCCH candidates (candidate sets) that the user equipment needs to perform blind detection is as high as 44, and each candidate set may carry PDCCH scheduling information, and the user equipment does not know which candidate sets the network will carry the scheduling information. Therefore, it is necessary to perform independent signal demapping, channel estimation (CE), noise estimation (NE), MIMO, polar decoder on each candidate set, and only after the complete decoding process, it is known whether the candidate set has a real and effective PDCCH payload.

[0004] In the implementation process, the inventor found that the calculation of each step in the above process is relatively complex, time-consuming and power-consuming on the user equipment, which shortens the effective time of subsequent system processing and may cause data loss in some cases. SUMMARY

[0005] In view of the above problems existing in the prior art, the present application provides a physical downlink control channel blind detection method for a 5G NR system, and on the other hand, provides a physical downlink control channel blind detection system for implementing the physical downlink control channel blind detection method.

[0006] The specific technical solutions are as follows:

[0007] The physical downlink control channel blind detection method for a 5G NR system comprises the following steps:

[0008] Step S1: obtaining a plurality of candidate sets to be detected in a search space;

[0009] Step S2: selecting one of the candidate sets;

[0010] Step S3: for the candidate set, in a channel estimation process, extracting a demodulation reference signal from the candidate set, performing correlation calculation on the demodulation reference signal and a local reference sequence to obtain a correlation result, and determining whether the candidate set contains a physical downlink control channel according to the correlation result;

[0011] If yes, go to step S4;

[0012] If no, return to step S2 to obtain a new candidate set;

[0013] Step S4: performing noise estimation, signal matrix demodulation and polar code decoding on the selected candidate set in sequence to obtain a decoding result corresponding to the candidate set, and determining whether the candidate set contains the physical downlink control channel according to the decoding result;

[0014] If yes, output the candidate set;

[0015] If no, return to step S2 to obtain a new candidate set.

[0016] On the other hand, after performing step S2 and before performing step S3, a signal energy screening process is further included, which is used to determine whether the candidate set contains the physical downlink control channel, and only the candidate set containing the physical downlink control channel is subjected to step S3;

[0017] The signal energy screening process comprises:

[0018] Step A1: calculating the signal energy in the frequency domain position of the candidate set;

[0019] Step A2: comparing the signal energy with a pre-set signal energy threshold value to determine whether the signal energy is greater than the signal energy threshold value;

[0020] If yes, go to step S3;

[0021] If not, return to step S2 to obtain the new candidate set.

[0022] On the other hand, step S3 includes:

[0023] Step S31: Perform channel estimation on the candidate set to obtain the estimation result;

[0024] Step S32: Filter the estimation result to obtain the demodulated reference signal;

[0025] Step S33: Perform autocorrelation analysis on the demodulated reference signal and the reference sequence to obtain the correlation result;

[0026] Step S34: Compare the correlation result with a preset correlation threshold to determine whether the correlation result is greater than the correlation threshold.

[0027] If so, proceed to step S4;

[0028] If not, return to step S2 to obtain the new candidate set.

[0029] On the other hand, after performing the solution of the signal matrix and before performing polar code decoding, a soft bit discrimination process is also included. The soft bit discrimination process is used to determine whether the candidate set after the solution of the signal matrix contains the physical downlink control channel, and polar code decoding is only performed on the candidate set that contains the physical downlink control channel.

[0030] The soft bit discrimination process includes:

[0031] Step B1: Extract soft bit information from the candidate set;

[0032] Step B2: Obtain the modulation signal information of the candidate set based on the soft bit information;

[0033] Step B3: Compare the modulation signal information with the pre-constructed modulation signal threshold to determine whether the modulation signal information is greater than the modulation signal threshold;

[0034] If so, decode the candidate set;

[0035] If not, return to step S2 to obtain the new candidate set.

[0036] On the other hand, in step B2, the method for generating the modulation signal information includes:

[0037] Multiple values ​​to be mapped to constellation points are determined from the soft bit information, and the modulation signal information is obtained by accumulating all the values ​​to be mapped.

[0038] A physical downlink control channel blind detection system of a 5G NR system, used for implementing the physical downlink control channel blind detection method described above;

[0039] The physical downlink control channel blind detection system comprises:

[0040] An effectiveness verification module, which acquires a plurality of candidate sets to be detected in a search space;

[0041] A candidate set extraction module, which is connected to the effectiveness verification module, and selects one candidate set from the plurality of candidate sets to be detected;

[0042] A channel estimation module, which is connected to the candidate set extraction module, and is used for performing channel estimation on the candidate set;

[0043] A correlation calculation module, which is connected to the channel estimation module, and extracts a demodulation reference signal from the candidate set extraction, and performs correlation calculation on the demodulation reference signal and a local reference sequence to obtain a correlation result, and judges whether to allow the candidate set to pass according to the correlation result;

[0044] A noise estimation module, which is connected to the correlation calculation module, and performs noise estimation on the candidate set output by the correlation calculation module;

[0045] A de-signal matrix module, which is connected to the noise estimation module, and performs de-signal matrix on the candidate set according to the output result of the noise estimation output module;

[0046] A polar code decoding module, which is connected to the de-signal matrix module, and decodes the candidate set after de-signal matrix, so as to screen the physical downlink control channel according to the decoding result.

[0047] In another aspect, it also comprises:

[0048] A signal energy screening module, an input end of which is connected to the candidate set extraction module, and an output end of which is connected to the channel estimation module, and which is used for judging whether to output the candidate set to the channel estimation module;

[0049] The signal energy screening module comprises:

[0050] a signal energy calculation module, configured to calculate signal energy in a frequency domain position for the candidate set;

[0051] a signal energy decision module, configured to compare the signal energy with a preset signal energy threshold value to determine whether to output the candidate set to the channel estimation module.

[0052] In another aspect, the correlation calculation module comprises:

[0053] a filtering module, configured to receive an estimation result output from the channel estimation module and filter the estimation result to obtain the demodulation reference signal;

[0054] a correlation calculation module, configured to generate a correlation result according to the demodulation reference signal and the reference sequence;

[0055] a correlation decision module, connected to the correlation calculation module, configured to determine whether to allow the candidate set to pass according to the correlation result.

[0056] In another aspect, a soft bit discrimination module is further included, an input end of the soft bit discrimination module is connected to the de-signal matrix module, an output end of the soft bit discrimination module is connected to the polar code decoding module, and the soft bit discrimination module is configured to determine whether to input the candidate set to the polar code decoding module.

[0057] The soft bit discrimination module comprises:

[0058] a soft bit extraction module, configured to extract soft bit information from the candidate set after de-signal matrix;

[0059] a modulation information generation module, connected to the soft bit extraction module, configured to generate modulation signal information according to the soft bit information;

[0060] a comparison module, connected to the modulation information generation module, configured to determine whether to input the candidate set to the polar code decoding module according to the modulation information and a preset modulation signal threshold.

[0061] In another aspect, the modulation information generation module accumulates a plurality of to-be-mapped values to be mapped to constellation points in the soft bit information to obtain the modulation signal information.

[0062] The above technical solution has the following advantages or beneficial effects: by performing correlation calculation based on the demodulation reference signal and the local reference sequence in the channel estimation process, it is determined whether the physical downlink control channel exists on the candidate set represented by the demodulation reference signal, and the candidate set in which the physical downlink control channel is impossible to exist is eliminated, thereby reducing the number of candidate sets that need to be blindly detected in the subsequent blind detection step, and improving the blind detection efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0063] The embodiments of the present application will be described in more detail with reference to the accompanying drawings. However, the accompanying drawings are only used for illustration and explanation, and do not constitute a limitation on the scope of the present application.

[0064] Figure 1 The physical downlink control channel blind detection method flowchart of the embodiment of the present application is shown in the figure.

[0065] Figure 2 The signal energy screening process flowchart in the embodiment of the present application is shown in the figure.

[0066] Figure 3 The step S3 sub-step flowchart in the embodiment of the present application is shown in the figure.

[0067] Figure 4 The soft bit discrimination process flowchart in the embodiment of the present application is shown in the figure.

[0068] Figure 5 The physical downlink control channel blind detection system principle block diagram in the embodiment of the present application is shown in the figure.

[0069] Figure 6 The signal energy screening module principle block diagram in the embodiment of the present application is shown in the figure.

[0070] Figure 7 The correlation calculation module principle block diagram in the embodiment of the present application is shown in the figure.

[0071] Figure 8 The soft bit discrimination module principle block diagram in the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0072] The technical solutions in the embodiments of the present application will be described in detail below with reference to the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0073] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0074] The technical solution described in the present application is implemented on the basis of 3GPP TS 38.211, TS 38.212, TS 38.213 standards, and the part not described in detail refers to 3GPP TS 38.211, TS 38.212, TS 38.213 standards implementation.

[0075] The present application will be further described below in conjunction with the drawings and specific embodiments, but not as a limitation of the present application.

[0076] The present application comprises:

[0077] A blind detection method of a physical downlink control channel of a 5G NR system, comprising:

[0078] Step S1: obtaining a plurality of candidate sets to be detected in the search space;

[0079] Step S2: selecting one candidate set;

[0080] Step S3: for the candidate set, in the channel estimation process, extracting the demodulation reference signal from the candidate set, calculating the correlation result by correlating the demodulation reference signal with the local reference sequence, and judging whether the candidate set contains the physical downlink control channel according to the correlation result;

[0081] If yes, go to step S4;

[0082] If no, return to step S2 to obtain a new candidate set;

[0083] Step S4: according to the screened candidate set, sequentially perform noise estimation, signal matrix demodulation, and polar code decoding to obtain the decoding result corresponding to the candidate set, and judge whether the candidate set contains the physical downlink control channel according to the decoding result;

[0084] If yes, output the candidate set;

[0085] If no, return to step S2 to obtain a new candidate set.

[0086] Specifically, in the prior art, after the signal extraction, channel estimation, noise estimation, MIMO decoding and polar code decoding process is performed on each candidate set, it is determined whether the candidate set contains the information of the physical downlink control channel according to the decoding result. The processing time is long and the efficiency is low. In the embodiment, in the process of channel estimation, the correlation between the demodulation reference signal (DM-RS) obtained in the signal extraction process and the reference sequence (UE DM-RS) corresponding to the demodulation reference signal generated in advance is calculated, so as to determine whether the position of the candidate set contains the physical downlink control channel corresponding to the local user equipment according to the demodulation reference signal, and the candidate set with low correlation is directly eliminated in this step without subsequent noise estimation, MIMO decoding and decoding process. In the general blind detection process, when the current candidate set does not contain the physical downlink control channel, the next candidate set is directly detected; only when the current candidate set may contain the physical downlink control channel, the subsequent noise estimation and the like are performed, so as to reduce the elimination step of the wrong candidate set in the overall blind detection process, and improve the processing efficiency.

[0087] In one embodiment, step S1 comprises:

[0088] In each slot, all candidate sets are divided for all search spaces that need to be blindly detected.

[0089] For the divided candidate sets, the time-frequency domain CCE position and the time sequence of each candidate set are calculated respectively.

[0090] The validity of each candidate set is calculated according to the candidate set validity formula, and the candidate set that needs to be blindly detected is screened out. The number of candidate sets that need to be blindly detected is not more than 44.

[0091] In one embodiment, after step S2 is performed, a signal energy screening process is further included before step S3 is performed. The signal energy screening process is used to determine whether the candidate set contains the physical downlink control channel, and only the candidate set containing the physical downlink control channel is executed in step S3.

[0092] As shown in Figure 2 , the signal energy screening process comprises:

[0093] Step A1: Calculate the signal energy in the frequency domain position of the candidate set.

[0094] Step A2: Compare the signal energy with the pre-set signal energy threshold value to determine whether the signal energy is greater than the signal energy threshold value.

[0095] If yes, go to step S3;

[0096] If no, return to step S2 to obtain a new candidate set.

[0097] Specifically, in the prior art, after the signal extraction, channel estimation, noise estimation, MIMO decoding, and polar code decoding process is performed on each candidate set, it is determined whether the candidate set contains the relevant information of the physical downlink control channel according to the decoding result, which is time-consuming and inefficient. In the embodiment, after the effectiveness of the candidate set in the search space is detected, the signal energy of the candidate set in the frequency domain is calculated before signal extraction. If the signal energy of the candidate set is too low, i.e. lower than the signal energy threshold, it indicates that the position of the candidate set contains a small amount of effective signals or only contains noise, so the candidate set is directly excluded without subsequent signal extraction and other steps, thereby reducing the exclusion steps of the wrong candidate set in the overall blind detection process, and improving the processing efficiency.

[0098] In one embodiment, as shown in FIG. 3, step S3 includes: Figure 3

[0099] Step S31: performing channel estimation on the candidate set to obtain an estimation result;

[0100] Step S32: filtering the estimation result to obtain a demodulation reference signal;

[0101] Step S33: performing autocorrelation analysis on the demodulation reference signal and the reference sequence to obtain a correlation result;

[0102] Step S34: comparing the correlation result with a pre-set correlation threshold to determine whether the correlation result is greater than the correlation threshold;

[0103] If yes, go to step S4;

[0104] If no, return to step S2 to obtain a new candidate set.

[0105] Specifically, to achieve better screening effect of the candidate set, in the embodiment, the data obtained after channel estimation of the candidate set is extracted, and the correlation between the demodulation reference signal and the reference sequence corresponding to the demodulation reference signal generated locally is analyzed. When the correlation is high, it indicates that the candidate set may carry the physical downlink control channel. When the correlation is low, it indicates that the position of the candidate set may be noise or irrelevant to the local physical downlink control channel, and the candidate set is discarded, skipping the subsequent noise estimation and other steps, and directly proceeding to the blind detection process of the next candidate set.

[0106] ​In the implementation process, the step S3 is performed in the process of channel estimation on the candidate set, that is, the candidate set extracts the demodulation reference signal, the phase tracking reference signal (PTRS), the sounding reference signal (SRS) and the channel state information reference signal (CSI-RS) in the process of channel estimation. In this process, the demodulation reference signal is conjugate multiplied and added with the local reference sequence by intercepting the demodulation reference signal part of the candidate set after the completion of the channel estimation and filtering, so that the demodulation reference signal can be operated according to the local reference sequence. The operation result is used as the correlation result to be compared with the correlation threshold value, so as to determine whether the demodulation reference signal is related to the local reference sequence.

[0107] In one embodiment, after the signal matrix is executed, the polar code decoding is performed, and further comprising a soft bit discrimination process before the polar code decoding, the soft bit discrimination process is used to determine whether the candidate set after the signal matrix contains the physical downlink control channel, and only the candidate set containing the physical downlink control channel is subjected to the polar code decoding.

[0108] As shown in Figure 4 , the soft bit discrimination process comprises:

[0109] Step B1: extracting the soft bit information of the candidate set;

[0110] Step B2: obtaining the modulation signal information of the candidate set according to the soft bit information;

[0111] Step B3: comparing the modulation signal information with the pre-constructed modulation signal threshold to determine whether the modulation signal information is greater than the modulation signal threshold;

[0112] If yes, the candidate set is decoded;

[0113] If no, return to step S2 to obtain a new candidate set.

[0114] Specifically, in the prior art, after the signal extraction, channel estimation, noise estimation, MIMO demodulation and polar code decoding are performed on each candidate set, it is determined whether the candidate set contains the information of the physical downlink control channel according to the decoding result, which is time-consuming and inefficient. In the embodiment, after the MIMO demodulation is completed, the soft bit information of the candidate set is extracted before the polar code decoding is performed, and the accumulated value of the value mapped to the constellation point in the soft bit information is used as the modulation signal information, which is compared with the modulation signal threshold constructed in advance. When the accumulated value of the value is small, it is generally considered that the candidate set contains more signal noise components, strong interference signals or low signal energy, which leads to fewer mappable values obtained by MIMO demodulation, and it is determined that the candidate set cannot be used for decoding to obtain the corresponding physical downlink control channel, and the next candidate set is directly converted for blind detection, reducing the subsequent polar code decoding steps.

[0115] In one embodiment, in step B2, the method for generating modulation signal information includes:

[0116] Determining a plurality of to-be-mapped values to be mapped to constellation points from the soft bit information, and accumulating all the to-be-mapped values to obtain modulation signal information.

[0117] A physical downlink control channel blind detection system of a 5G NR system is used to implement the above-mentioned physical downlink control channel blind detection method.

[0118] As shown in Figure 5 The physical downlink control channel blind detection system includes:

[0119] An effectiveness verification module 1 acquires a plurality of candidate sets to be detected in a search space;

[0120] A candidate set extraction module 2 is connected to the effectiveness verification module 1, and the candidate set extraction module 2 selects one candidate set from the plurality of candidate sets to be detected;

[0121] A channel estimation module 3 is connected to the candidate set extraction module 3, and the channel estimation module 3 is used for channel estimation of the candidate set;

[0122] A correlation calculation module 4 is connected to the channel estimation module 3, and the correlation calculation module 4 demodulates the reference signal of the candidate set, and calculates the correlation between the demodulated reference signal and the local reference sequence to obtain a correlation result, and determines whether the candidate set is allowed to pass according to the correlation result;

[0123] A noise estimation module 5 is connected to the correlation calculation module 4, and the noise estimation module 5 performs noise estimation on the candidate set output by the correlation calculation module;

[0124] A de-signal matrix module 6 is connected to the noise estimation module 5, and the de-signal matrix module 6 performs de-signal matrix on the candidate set according to the output of the noise estimation module;

[0125] A polar code decoding module 7 is connected to the de-signal matrix module 6, and the polar code decoding module 7 decodes the candidate set after de-signal matrix, so as to filter the physical downlink control channel according to the decoding result.

[0126] Specifically, in the prior art, after the signal extraction, channel estimation, noise estimation, de-MIMO, and polar code decoding process is performed on each candidate set, it is determined whether the current candidate set contains the relevant information of the physical downlink control channel according to the decoding result. The processing time is long and the efficiency is low. In the embodiment, the correlation calculation module 4 is arranged at the back of the channel estimation module 3. The correlation calculation module 4 performs correlation calculation on the demodulation reference signal (DM-RS) obtained in the signal extraction process and the reference sequence (UE DM-RS) corresponding to the demodulation reference signal which is generated locally in advance, so as to determine whether the position of the candidate set contains the physical downlink control channel corresponding to the local user equipment according to the demodulation reference signal. The correlation calculation module 4 selects whether to output the candidate set to the noise estimation module 5 at the back according to the determination result, so as to reduce the exclusion step of the wrong candidate set in the whole blind detection process, and further improve the processing efficiency.

[0127] In one embodiment, as shown in FIG. 21, the signal energy screening module 21 further includes: Figure 6

[0128] The signal energy screening module 21 is connected to the candidate set extraction module 2 at the input end and connected to the channel estimation module 3 at the output end. The signal energy screening module 21 is used to determine whether to output the candidate set to the channel estimation module.

[0129] The signal energy screening module 21 includes:

[0130] The signal energy calculation module 211 calculates the signal energy in the frequency domain position of the candidate set.

[0131] The signal energy decision module 212 compares the signal energy with the pre-set signal energy threshold value to determine whether to output the candidate set to the channel estimation module 3.

[0132] ​Specifically, in the prior art, the signal extraction, channel estimation, noise estimation, MIMO decoding, and polar code decoding process is performed on each candidate set in turn and in a loop, and then it is determined whether the candidate set contains the relevant information of the physical downlink control channel according to the decoding result. The processing time is long and the efficiency is low. In the embodiment, after the validity detection of the candidate set in the search space is completed by the validity verification module 1, the candidate set extraction module 2 selects a candidate set in the search space to perform the normal blind detection process. Then, the signal energy screening module 21 is arranged in the front stage of the channel estimation module 3, the signal energy of the candidate set in the frequency domain is calculated on the signal energy calculation module 211 in the signal energy screening module 21, and then the signal energy judgment module 212 judges. If the signal energy of the candidate set is too low, that is, lower than the signal energy threshold, it indicates that the position where the candidate set is located contains a small amount of effective signals or only contains noise, so the candidate set is directly excluded and will not be output to the channel estimation module 3 in the rear stage. In this way, the exclusion step of the wrong candidate set in the overall blind detection process is reduced, and the processing efficiency is improved.

[0133] In one embodiment, as shown in FIG. 4, the correlation calculation module 4 includes: Figure 7

[0134] The filtering module 41 receives the estimation result output from the channel estimation module 3 and filters the estimation result to obtain the demodulation reference signal.

[0135] The correlation calculation module 42 generates a correlation result according to the demodulation reference signal and the reference sequence.

[0136] The correlation decision module 43 is connected to the correlation calculation module 43, and the correlation decision module determines whether to allow the candidate set to pass according to the correlation result.

[0137] Specifically, to achieve better screening effect of the candidate set, in the embodiment, the data obtained after the channel estimation of the candidate set is extracted, the demodulation reference signal is extracted, and the filtering module 41 is filtered to output the demodulation reference signal that can be used for correlation calculation. Then, the correlation calculation module 42 analyzes the correlation of the two based on the reference sequence corresponding to the demodulation reference signal generated locally, and uses the correlation decision module 43 to determine whether to output the candidate set to the noise estimation module 5 in the rear stage. When the correlation is high, it indicates that the candidate set may carry the physical downlink control channel; when the correlation is low, it indicates that the position of the candidate set may be noise or irrelevant to the local physical downlink control channel, and then the candidate set is discarded, the subsequent noise estimation step is skipped, and the blind detection process of the next candidate set is directly converted. ​

[0138] In one embodiment, a soft bit discrimination module 61 is further included, an input end of the soft bit discrimination module 61 is connected to the signal demodulation matrix module 6, and an output end of the soft bit discrimination module 61 is connected to the polar code decoding module 7, and the soft bit discrimination module 61 is configured to determine whether to input the candidate set into the polar code decoding module 7;

[0139] The soft bit discrimination module 61 includes:

[0140] A soft bit extraction module 611 is configured to extract soft bit information from the candidate set after signal demodulation matrix;

[0141] A modulation information generation module 612 is connected to the soft bit extraction module 611, and the modulation information generation module 612 is configured to generate modulation signal information according to the soft bit information;

[0142] A comparison module 613 is connected to the modulation information generation module 612, and the comparison module 613 is configured to determine whether to input the candidate set into the polar code decoding module 7 according to the modulation signal information and a preset modulation signal threshold.

[0143] The modulation information generation module 612 is configured to accumulate a plurality of to-be-mapped values in the soft bit information, which are to be mapped to constellation points, to obtain the modulation signal information.

[0144] Specifically, in the prior art, the signal extraction, channel estimation, noise estimation, MIMO demodulation, and polar code decoding process need to be performed on each candidate set one by one and in a loop, and only after the process is completed, it can be determined according to the decoding result whether the current candidate set contains relevant information of the physical downlink control channel. The process is time-consuming and inefficient. In the embodiment, the soft bit discrimination module 61 is added after the signal demodulation matrix module 6 and before the polar code decoding module 7. The soft bit extraction module 611 extracts soft bit information from the candidate set, and the modulation information generation module 612 takes the accumulated value of the values mapped to the constellation points in the soft bit information as the modulation signal information, so that the comparison module 613 can compare according to the preset modulation signal threshold. When the accumulated value of the values is small, it can be generally considered that the candidate set contains more signal noise components, strong interference signals, or low signal energy, which leads to fewer values that can be mapped after MIMO demodulation, and thus it is determined that the candidate set cannot be used for decoding to obtain the corresponding physical downlink control channel, and the next candidate set is directly subjected to blind detection, thereby reducing the subsequent polar code decoding steps.

[0145] The above merely preferred embodiments of the present application and are not intended to limit the embodiments and protection scope of the present application. Those skilled in the art should be able to understand that any equivalent substitutions and obvious changes made according to the present application description and drawings should be included in the protection scope of the present application.

Claims

1. A blind detection method for the physical downlink control channel of a 5G NR system, characterized in that, include: Step S1: Obtain multiple candidate sets to be detected in the search space; Step S2: Select one of the candidate sets; Step S3: For the candidate set, during the channel estimation process, a demodulation reference signal is extracted from the candidate set, and the correlation between the demodulation reference signal and the local reference sequence is calculated to obtain the correlation result. Based on the correlation result, it is determined whether the candidate set contains a physical downlink control channel. If so, proceed to step S4; If not, return to step S2 to obtain the new candidate set; During the channel estimation process, the candidate set that does not include the physical downlink control channel is directly discarded based on the correlation results; In step S3, the candidate set is filtered according to the signal energy and modulation signal information of the candidate set to remove erroneous candidate sets. The method for generating the modulation signal information includes: Multiple values ​​to be mapped to constellation points are determined from the soft bit information in the candidate set, and the modulation signal information is obtained by accumulating all the values ​​to be mapped. Step S4: Based on the selected candidate set, perform noise estimation, signal matrix decomposition, and polar code decoding in sequence to obtain the decoding result corresponding to the candidate set, and determine whether the candidate set contains the physical downlink control channel based on the decoding result; If so, output the candidate set; If not, return to step S2 to obtain the new candidate set.

2. The physical downlink control channel blind detection method according to claim 1, characterized in that, After performing step S2 and before performing step S3, a signal energy filtering process is included. The signal energy filtering process is used to determine whether the candidate set contains the physical downlink control channel, and step S3 is performed only on the candidate set that contains the physical downlink control channel. The signal energy filtering process includes: Step A1: Calculate the signal energy at the frequency domain location for the candidate set; Step A2: Compare the signal energy with a preset signal energy threshold value to determine whether the signal energy is greater than the signal energy threshold value; If so, proceed to step S3; If not, return to step S2 to obtain the new candidate set.

3. The physical downlink control channel blind detection method according to claim 1, characterized in that, Step S3 includes: Step S31: Perform channel estimation on the candidate set to obtain the estimation result; Step S32: Filter the estimation result to obtain the demodulated reference signal; Step S33: Perform autocorrelation analysis on the demodulated reference signal and the reference sequence to obtain the correlation result; Step S34: Compare the correlation result with a preset correlation threshold to determine whether the correlation result is greater than the correlation threshold. If so, proceed to step S4; If not, return to step S2 to obtain the new candidate set.

4. The physical downlink control channel blind detection method according to claim 1, characterized in that, After performing the signal matrix solution and before performing polar code decoding, a soft bit discrimination process is also included. The soft bit discrimination process is used to determine whether the candidate set after the signal matrix solution contains the physical downlink control channel, and polar code decoding is only performed on the candidate set that contains the physical downlink control channel. The soft bit discrimination process includes: Step B1: Extract soft bit information from the candidate set; Step B2: Obtain the modulation signal information of the candidate set based on the soft bit information; Step B3: Compare the modulation signal information with the pre-constructed modulation signal threshold to determine whether the modulation signal information is greater than the modulation signal threshold; If so, decode the candidate set; If not, return to step S2 to obtain the new candidate set.

5. A blind detection system for the physical downlink control channel of a 5G NR system, characterized in that, Used to implement the physical downlink control channel blind detection method as described in any one of claims 1-4; The physical downlink control channel blind detection system includes: A validity verification module, which obtains multiple candidate sets to be detected in the search space; A candidate set extraction module, which is connected to the validity verification module, selects one candidate set from the multiple candidate sets to be detected. A channel estimation module, connected to the candidate set extraction module, is used to perform channel estimation on the candidate set; A correlation calculation module is connected to the channel estimation module. The correlation calculation module extracts a demodulated reference signal from the candidate set, performs correlation calculation between the demodulated reference signal and a local reference sequence to obtain a correlation result, and determines whether the candidate set is allowed to pass based on the correlation result. A noise estimation module is connected to the correlation calculation module, and the noise estimation module performs noise estimation on the candidate set output by the correlation calculation module. A signal matrix solution module is connected to the noise estimation module, and the signal matrix solution module performs a signal matrix solution on the candidate set based on the output of the noise estimation output module. A polar code decoding module is connected to the descrambling signal matrix module. The polar code decoding module decodes the candidate set after the descrambling signal matrix to obtain the physical downlink control channel based on the decoding result.

6. The physical downlink control channel blind detection system according to claim 5, characterized in that, Also includes: A signal energy filtering module, wherein the input of the signal energy filtering module is connected to the candidate set extraction module, and the output of the signal energy filtering module is connected to the channel estimation module, and the signal energy filtering module is used to determine whether to output the candidate set to the channel estimation module; The signal energy filtering module includes: A signal energy calculation module, which calculates the signal energy at a frequency domain location in the candidate set; The signal energy decision module compares the signal energy with a pre-set signal energy threshold value to determine whether to output the candidate set to the channel estimation module.

7. The physical downlink control channel blind detection system according to claim 5, characterized in that, The correlation calculation module includes: A filtering module receives the estimation result output from the channel estimation module and filters the estimation result to obtain the demodulation reference signal; A correlation calculation module, which generates a correlation result based on the demodulated reference signal and the reference sequence; A correlation decision module is connected to the correlation calculation module, and the correlation decision module determines whether to allow the candidate set to pass based on the correlation result.

8. The physical downlink control channel blind detection system according to claim 5, characterized in that, It also includes a soft bit discrimination module, the input of which is connected to the solution signal matrix module, and the output of which is connected to the polar code decoding module. The soft bit discrimination module is used to determine whether to input the candidate set into the polar code decoding module. The soft bit discrimination module includes: A soft bit extraction module extracts soft bit information from the candidate set after self-decomposing the signal matrix; A modulation information generation module is connected to the soft bit extraction module, and the modulation information generation module generates modulation signal information based on the soft bit information; A comparison module is connected to the modulation information generation module. The comparison module determines whether to input the candidate set into the polar code decoding module based on the modulation information and a preset modulation signal threshold.

9. The physical downlink control channel blind detection system according to claim 8, characterized in that, The modulation information generation module accumulates the values ​​of multiple points to be mapped to constellation points in the soft bit information to obtain the modulation signal information.

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