CN116055006A - Physical downlink control channel blind detection method and system of 5G NR system - Google Patents

Abstract

The invention relates to the technical field of 5GNR channel detection, in particular to a physical downlink control channel blind detection method and a physical downlink control channel blind detection system of a 5G NR system, comprising the following steps: acquiring a plurality of candidate sets to be detected in a search space; selecting a candidate set, extracting demodulation reference signals from the candidate set in the channel estimation process aiming at the candidate set, carrying out correlation calculation on the demodulation reference signals and a local reference sequence to obtain a correlation result, and judging whether the candidate set contains a physical downlink control channel or not; if yes, carrying out subsequent treatment; if not, a new candidate set is acquired. The beneficial effects are that: in the channel estimation process, correlation calculation is carried out based on the demodulation reference signal and a local reference sequence, so that whether a physical downlink control channel exists in a candidate set represented by the demodulation reference signal is judged, and the candidate set which cannot exist the physical downlink control channel is removed, so that the number of candidate sets which need to be subjected to blind detection in a subsequent blind detection step is reduced, and the blind detection efficiency is improved.

Description

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

technical field

The present invention relates to the technical field of 5G NR channel detection, in particular to a blind detection method and system for a physical downlink control channel of a 5G NR system.

Background technique

5G NR (New Radio) is a global 5G standard based on a new air interface design based on OFDM (Orthogonal Frequency Division Multiplexing, Orthogonal Frequency Division Multiplexing technology). In the 5G NR system, the frequency domain scheduling range information of PDCCH (Physical Downlink Control Channel, physical downlink control channel) and the time domain OFDM symbol number information are encapsulated in CORESET (control resource set), the time domain start symbol information and detection period Information such as is encapsulated in 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 COERSET, but cannot determine which RBs will be sent. Therefore, after the physical resource information, search space type (CSS or USS) and other information are determined for the PDCCH channel, the user equipment will search for the PDCCH on the CORESET in different search spaces and according to different RNTI types. Since the user equipment does not clearly know the time-frequency position of the PDCCH transmission, it can only continuously demodulate the candidate set of the PDCCH. Therefore, this process is called blind detection of the PDCCH.

In the prior art, the maximum number of PDCCH candidates (candidate sets) that the user equipment needs to perform blind detection is 44, and each candidate set may carry PDCCH scheduling information, and the user equipment does not know which candidate sets the network will be on Carry these scheduling information. Therefore, it is necessary to do a complete set of independent signal extraction (RE demapping), channel estimation (CE), noise estimation (NE), solution signal matrix (MIMO), and polar decoder (polar decoder) for each candidate set. After the decoding process, it is known whether there is a real and effective PDCCH payload in the candidate set.

During the implementation process, the inventors found that the calculation of each step in the above process is relatively complex, time-consuming and consumes a lot of power consumption on the user equipment, which shortens the effective time of subsequent system processing, and in some cases leads to data loss.

Contents of the invention

In view of the above-mentioned problems existing in the prior art, a physical downlink control channel blind detection method of a 5G NR system is now provided, and on the other hand, a physical downlink control channel for implementing the physical downlink control channel blind detection method is also provided Blind detection system.

The specific technical scheme is as follows:

A physical downlink control channel blind detection method for a 5G NR system, comprising:

Step S1: Obtain multiple candidate sets to be detected in the search space;

Step S2: selecting one of the candidate sets;

Step S3: For the candidate set, during the channel estimation process, extract the demodulation reference signal for the candidate set, perform correlation calculation on the demodulation reference signal and the local reference sequence to obtain a correlation result, according to the As a result of the correlation, it is judged whether the candidate set contains a physical downlink control channel;

If yes, turn to step S4;

If not, return to step S2 to obtain a new candidate set;

Step S4: Perform noise estimation, signal matrix solution, and polar code decoding sequentially according to the screened candidate set to obtain a decoding result corresponding to the candidate set, and judge whether the candidate set is based on the decoding result Including the physical downlink control channel;

If so, output the candidate set;

If not, return to step S2 to obtain a new candidate set.

On the other hand, after performing the step S2 and before performing the step S3, a signal energy screening process is also included, the signal energy screening process is used to determine whether the candidate set contains the physical downlink control channel, and only performing the step S3 for the candidate set including the physical downlink control channel;

The signal energy screening process includes:

Step A1: Calculating the signal energy in the frequency domain position for the candidate set;

Step A2: comparing the signal energy with a preset signal energy threshold, and judging whether the signal energy is greater than the signal energy threshold;

If yes, turn to step S3;

If not, return to step S2 to obtain a new candidate set.

On the other hand, the step S3 includes:

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

Step S32: Filter the estimation result to obtain the demodulation reference signal;

Step S33: performing an autocorrelation analysis on the demodulation reference signal and the reference sequence to obtain the correlation result;

Step S34: comparing the correlation result with a preset correlation threshold value, and judging whether the correlation result is greater than the correlation threshold value

If yes, turn to step S4;

If not, return to step S2 to obtain a new candidate set.

On the other hand, after performing signal matrix decompression and before performing polar code decoding, a soft bit discrimination process is also included, and the soft bit discrimination process is used to determine whether the candidate set after decompression signal matrix contains the physical a downlink control channel, and only perform polar code decoding on the candidate set including the physical downlink control channel;

The soft bit discrimination process includes:

Step B1: extracting soft bit information from the candidate set;

Step B2: Obtain modulation signal information of the candidate set according to the soft bit information;

Step B3: comparing the modulated signal information with a pre-built modulated signal threshold, and judging whether the modulated signal information is greater than the modulated signal threshold;

If so, decoding the candidate set;

If not, return to step S2 to obtain a new candidate set.

On the other hand, in the step B2, the method for generating the modulated signal information includes:

A plurality of values to be mapped to constellation points are determined from the soft bit information, and all the values to be mapped are accumulated to obtain the modulated signal information.

A physical downlink control channel blind detection system of a 5G NR system, used to implement the above-mentioned physical downlink control channel blind detection method;

The physical downlink control channel blind detection system includes:

A validity verification module, the validity verification module obtains a plurality of candidate sets to be detected in the search space;

A candidate set extraction module, the candidate set extraction module is connected to the validity verification module, and the candidate set extraction module selects one of the candidate sets from a plurality of candidate sets to be detected;

A channel estimation module, the channel estimation module is connected to the candidate set extraction module, and the channel estimation module is used to perform channel estimation on the candidate set;

A correlation calculation module, the correlation calculation module is connected to the channel estimation module, the correlation calculation module extracts a demodulation reference signal from the candidate set, and correlates the demodulation reference signal with a local reference sequence calculating a correlation result, and judging whether to allow the candidate set to pass according to the correlation result;

A noise estimation module, the 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, the signal matrix solution module is connected to the noise estimation module, and the signal matrix solution module performs signal matrix solution for the candidate set according to the output result of the noise estimation output module;

A polar code decoding module, the polar code decoding module is connected to the signal matrix solution module, and the polar code decoding module decodes the candidate set after the signal matrix solution, so that according to the decoding result The physical downlink control channel is obtained by screening.

On the other hand, also include:

A signal energy screening module, the input end of the signal energy screening module is connected to the candidate set extraction module, the output end of the signal energy screening module is connected to the channel estimation module, and the signal energy screening module is used to judge whether to The channel estimation module outputs the candidate set;

The signal energy screening module includes:

a signal energy calculation module, the signal energy calculation module calculates the signal energy in the frequency domain position for the candidate set;

A signal energy judging module, the signal energy judging module compares the signal energy with a preset signal energy threshold to judge whether to output the candidate set to the channel estimation module.

On the other hand, the correlation calculation module includes:

a filtering module, the filtering module receives an estimation result output from the channel estimation module, and filters the estimation result to obtain the demodulation reference signal;

a correlation calculation module, the correlation calculation module generates a correlation result according to the demodulation reference signal and the reference sequence;

A correlation judgment module, the correlation judgment module is connected to the correlation calculation module, and the correlation judgment module judges whether to allow the candidate set to pass according to the correlation result.

On the other hand, it also includes a soft bit discrimination module, the input end of the soft bit discrimination module is connected to the de-signal matrix module, the output end of the soft bit discrimination module is connected to the polar code decoding module, and the soft bit discrimination module is connected to the polar code decoding module. The bit discrimination module is used to judge whether to input the candidate set into the polar code decoding module;

Described soft bit discriminating module comprises:

A soft bit extraction module, the soft bit extraction module extracts soft bit information from the candidate set after decomposing the signal matrix;

A modulation information generation module, the modulation information generation module is connected to the soft bit extraction module, and the modulation information generation module generates modulation signal information according to the soft bit information;

A comparison module, the comparison module is connected to the modulation information generation module, and the comparison module judges whether to input the candidate set into the polar code decoding module according to the modulation information and a preset modulation signal threshold.

On the other hand, the modulation information generating module accumulates a plurality of values to be mapped to constellation points in the soft bit information to obtain the modulation signal information.

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 judged whether there is a physical downlink in the candidate set represented by the demodulation reference signal control channel, and eliminate candidate sets that are unlikely to have physical downlink control channels, reducing the number of candidate sets that need to be blindly detected in subsequent blind detection steps, thereby improving blind detection efficiency.

Description of drawings

Embodiments of the present invention are more fully described with reference to the accompanying drawings. However, the accompanying drawings are for illustration and illustration only, and do not limit the scope of the present invention.

FIG. 1 is a flowchart of a method for blind detection of a physical downlink control channel according to an embodiment of the present invention;

Fig. 2 is the flow chart of signal energy screening process in the embodiment of the present invention;

Fig. 3 is the sub-step flowchart of step S3 in the embodiment of the present invention;

Fig. 4 is the flow chart of soft bit discrimination process in the embodiment of the present invention;

5 is a functional block diagram of a physical downlink control channel blind detection system in an embodiment of the present invention;

Fig. 6 is a functional block diagram of a signal energy screening module in an embodiment of the present invention;

Fig. 7 is a functional block diagram of a correlation calculation module in an embodiment of the present invention;

Fig. 8 is a functional block diagram of a soft bit discrimination module in an embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

It should be noted that, in the case of no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

The technical solution recorded in the present invention is implemented on the basis of 3GPP TS 38.211, TS 38.212, and TS 38.213 standards. For parts not described in detail, please refer to 3GPP TS 38.211, TS 38.212, and TS 38.213 standards for implementation.

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but not as a limitation of the present invention.

The present invention includes:

A physical downlink control channel blind detection method for a 5G NR system, comprising:

Step S1: Obtain multiple candidate sets to be detected in the search space;

Step S2: Select a candidate set;

Step S3: For the candidate set, during the channel estimation process, extract the demodulation reference signal for the candidate set, perform correlation calculation between the demodulation reference signal and the local reference sequence to obtain the correlation result, and judge whether the candidate set contains Physical downlink control channel;

If yes, turn to step S4;

If not, return to step S2 to obtain a new candidate set;

Step S4: Carry out noise estimation, signal matrix solution, and polar code decoding sequentially according to the filtered candidate set to obtain a decoding result corresponding to the candidate set, and judge whether the candidate set includes a physical downlink control channel according to the decoding result;

If so, output the candidate set;

If not, return to step S2 to obtain a new candidate set.

Specifically, in the prior art, it is necessary to carry out the process of signal extraction, channel estimation, noise estimation, MIMO solution, and polar code decoding one by one and cyclically for several candidate sets before it can be judged according to the decoding result Does the current candidate set contain relevant information of the physical downlink control channel? Its processing takes a long time and is inefficient. In this embodiment, in the process of channel estimation, according to the demodulation obtained in the process of signal extraction The reference signal (DM-RS) and the local pre-generated reference sequence (UE DM-RS) corresponding to the demodulation reference signal are used for correlation calculation, so as to judge whether the position of the candidate set contains Corresponding to the physical downlink control channel of the local user equipment, the candidate sets with low correlation are directly eliminated in this step, without performing subsequent noise estimation, MIMO solution and decoding processes. In the general blind detection process, when this step shows that the current candidate set does not contain the physical downlink control channel, it will directly turn to the blind detection process for the next candidate set; only when this step shows that the current candidate set may contain Subsequent noise estimation and other content are performed only when the physical downlink control channel is used, thereby reducing the steps of eliminating the wrong candidate set in the overall blind detection process, thereby improving the processing efficiency.

In one embodiment, step S1 includes:

In each slot (slot), for all search spaces that require blind detection, divide and obtain all candidate sets;

For the divided candidate sets, respectively calculate the time-frequency domain CCE position and time sequence order of each candidate set;

Calculate the validity of each candidate set according to the validity formula of the candidate set, and then screen out the candidate sets that need blind detection. The number of candidate sets that need blind detection is not more than 44.

In one embodiment, after step S2 is performed and before step S3 is performed, a signal energy screening process is included, the signal energy screening process is used to determine whether the candidate set contains a physical downlink control channel, and only for the candidate set that contains a physical downlink control channel Execute step S3;

As shown in Figure 2, the signal energy screening process includes:

Step A1: Calculate the signal energy in the frequency domain position for the candidate set;

Step A2: Comparing the signal energy with a preset signal energy threshold, and judging whether the signal energy is greater than the signal energy threshold;

If yes, turn to step S3;

If not, return to step S2 to obtain a new candidate set.

Specifically, in the prior art, it is necessary to carry out the process of signal extraction, channel estimation, noise estimation, MIMO solution, and polar code decoding one by one and cyclically for several candidate sets before it can be judged according to the decoding result Whether the current candidate set contains the relevant information of the physical downlink control channel, its processing takes a long time and is inefficient. In this embodiment, after completing the validity detection of the candidate set in the search space, in Before signal extraction, the calculation of the signal energy of the candidate set itself in the frequency domain is added. If the signal energy of the candidate set itself is too low, that is, lower than the signal energy threshold, it indicates that the position of the candidate set contains The number of effective signals is small or only contains noise, so the candidate set is directly eliminated without subsequent steps such as signal extraction, so as to reduce the elimination steps of the wrong candidate set in the overall blind detection process, thereby improving processing efficiency.

In one embodiment, as shown in Figure 3, step S3 includes:

Step S31: Perform channel estimation on the candidate set to obtain an estimation result;

Step S32: Filter the estimation result to obtain the demodulation reference signal;

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

Step S34: Comparing the correlation result with a preset correlation threshold value to determine whether the correlation result is greater than the correlation threshold value;

If yes, turn to step S4;

If not, return to step S2 to obtain a new candidate set.

Specifically, in order to achieve a better screening effect on the candidate set, in this embodiment, for the candidate set to obtain data after channel estimation, by extracting the demodulation reference signal, and based on the locally generated reference corresponding to the demodulation reference signal Sequence analysis of the correlation between the two; when the correlation is high, it indicates that the candidate set may carry a physical downlink control channel; and when the correlation is low, it indicates that the location of the candidate set may be noise or local The physical downlink control channel is irrelevant, and then the candidate set is discarded, the subsequent steps such as noise estimation are skipped, and the process of blind detection for the next candidate set is directly transferred.

In the implementation process, the above step S3 is performed in the process of channel estimation for the candidate set, that is, in the process of channel estimation for the candidate set, the demodulation reference signal, phase tracking reference signal (PTRS), and sounding reference signal will be extracted. (SRS) and Channel State Information Reference Signal (CSI-RS). In this process, the demodulation reference signal part of the candidate set after channel estimation is intercepted and filtered, so that the demodulation reference signal can perform conjugate multiplication and addition operations according to the local reference sequence, and the operation results are used as correlation The result is judged with the correlation threshold value, so as to judge whether the demodulation reference signal is correlated with the local reference sequence.

In one embodiment, after performing signal matrix decompression and before performing polar code decoding, a soft bit discrimination process is further included, and the soft bit discrimination process is used to determine whether the candidate set after decomposing signal matrix contains a physical downlink control channel, and only perform polar code decoding on the candidate set including the physical downlink control channel;

As shown in Figure 4, the soft bit discrimination process includes:

Step B1: extracting soft bit information from the candidate set;

Step B2: Obtain the modulated signal information of the candidate set according to the soft bit information;

Step B3: comparing the modulated signal information with the pre-built modulated signal threshold to determine whether the modulated signal information is greater than the modulated signal threshold;

If so, decode the candidate set;

If not, return to step S2 to obtain a new candidate set.

Specifically, in the prior art, it is necessary to carry out the process of signal extraction, channel estimation, noise estimation, MIMO solution, and polar code decoding one by one and cyclically for several candidate sets before it can be judged according to the decoding result Does the current candidate set contain the relevant information of the physical downlink control channel? It takes a long time to process and has low efficiency. In this embodiment, after completing the MIMO solution and before performing polar code decoding, the The set extracts the soft bit information, and uses the accumulated value of the value mapped to the constellation point in the soft bit information as the modulation signal information, and then compares it with the pre-built modulation signal threshold; when the accumulated value of the value is small, it can generally be considered that the The candidate set contains many signal noise components, strong interference signals, or low signal energy, resulting in fewer mappable values obtained by solving MIMO, and then it is determined that the candidate set cannot be used for decoding to obtain the corresponding physical downlink control channel. Directly switch to blind detection for the next candidate set, reducing the steps of subsequent polar code decoding.

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

Multiple values to be mapped to the constellation points are determined from the soft bit information, and all the values to be mapped are accumulated to obtain modulation signal information.

A physical downlink control channel blind detection system of a 5G NR system, used to implement the above-mentioned physical downlink control channel blind detection method;

As shown in Figure 5, the physical downlink control channel blind detection system includes:

Validity verification module 1, the validity verification module 1 acquires a plurality of candidate sets to be detected in the search space;

The candidate set extraction module 2, the candidate set extraction module 2 is connected to the validity verification module 1, and the candidate set extraction module 2 selects a candidate set from a plurality of candidate sets to be detected;

A channel estimation module 3, the channel estimation module 3 is connected to the candidate set extraction module 3, and the channel estimation module 3 is used to perform channel estimation on the candidate set;

The correlation calculation module 4, the correlation calculation module 4 is connected to the channel estimation module 3, the correlation calculation module 4 extracts the demodulation reference signal for the candidate set, and performs correlation calculation between the demodulation reference signal and the local reference sequence to obtain a correlation result, Judging whether to allow the candidate set to pass according to the correlation result;

Noise estimation module 5, noise estimation module 5 connects correlation calculation module 4, noise estimation module 5 carries out noise estimation to the candidate set that correlation calculation module outputs;

Solution signal matrix module 6, solution signal matrix module 6 connects noise estimation module 5, solution signal matrix module 6 carries out solution signal matrix to candidate set according to the output result of noise estimation output module;

The polar code decoding module 7, the polar code decoding module 7 is connected to the signal matrix solution module 6, and the polar code decoding module 7 decodes the candidate set after the signal matrix solution, so as to obtain the physical downlink according to the decoding result control channel.

Specifically, in the prior art, it is necessary to carry out the process of signal extraction, channel estimation, noise estimation, MIMO solution, and polar code decoding one by one and cyclically for several candidate sets before it can be judged according to the decoding result Whether the current candidate set contains the relevant information of the physical downlink control channel, its processing takes a long time and the problem of low efficiency, in this embodiment, by setting the correlation calculation module 3 in the subsequent stage of the channel estimation module 3, in In the correlation calculation module 4, the correlation calculation is performed according to 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 locally, thereby according to Demodulate the reference signal to determine whether the position of the candidate set contains the physical downlink control channel corresponding to the local user equipment, and the correlation calculation module 4 selects whether to let the candidate set output to the noise estimation of the subsequent stage according to the judgment result In module 5, the steps of eliminating the wrong candidate sets in the overall blind detection process are reduced, thereby improving the processing efficiency.

In one embodiment, as shown in Figure 6, also includes:

Signal energy screening module 21, the input end of signal energy screening module 21 is connected to candidate set extraction module 2, the output end of signal energy screening module 21 is connected to channel estimation module 3, and signal energy screening module 21 is used for judging whether to output candidate to channel estimation module set;

Signal energy screening module 21 includes:

The signal energy calculation module 211, the signal energy calculation module 211 calculates the signal energy in the frequency domain position for the candidate set;

A signal energy judging module 212 . The signal energy judging module 212 compares the signal energy with a preset signal energy threshold to judge whether to output the candidate set to the channel estimation module 3 .

Specifically, in the prior art, it is necessary to carry out the process of signal extraction, channel estimation, noise estimation, MIMO solution, and polar code decoding one by one and cyclically for several candidate sets before it can be judged according to the decoding result Whether the current candidate set contains the relevant information of the physical downlink control channel, its processing takes a long time and the problem of low efficiency, in this embodiment, after the validity verification module 1 completes the candidate set in the search space After the validity detection, a candidate set in the search space is selected by the candidate set extraction module 2 to carry out the normal blind detection process; subsequently, by setting the signal energy screening module 21 at the front stage of the channel estimation module 3, the signal energy screening module 21 The signal energy calculation module 211 in the module 21 calculates the signal energy of the candidate set itself in the frequency domain, and then judges by the signal energy judgment module 212. If the signal energy of the candidate set itself is too low, that is, lower than the signal energy The threshold value indicates that the position of the candidate set contains less effective signals or only contains noise, so the candidate set is directly eliminated and will not be output to the subsequent channel estimation module 3, thereby reducing The step of eliminating the wrong candidate set in the overall blind detection process is eliminated, thereby improving the processing efficiency.

In one embodiment, as shown in Figure 7, the correlation calculation module 4 includes:

A filtering module 41, the filtering module 41 receives the estimation result output from the channel estimation module 3, and filters the estimation result to obtain a demodulation reference signal;

A correlation calculation module 42, the correlation calculation module 42 generates a correlation result according to the demodulation reference signal and the reference sequence;

The correlation judgment module 43, the correlation judgment module 43 is connected to the correlation calculation module 43, and the correlation judgment module judges whether to allow the candidate set to pass according to the correlation result.

Specifically, in order to achieve a better screening effect on the candidate set, in this embodiment, the data obtained after channel estimation for the candidate set is obtained by extracting the demodulation reference signal, and filtered by the filtering module 41 to output an output that can be used to calculate the correlation The demodulation reference signal, then, the correlation calculation module 42 analyzes the correlation between the two based on the locally generated reference sequence corresponding to the demodulation reference signal, and uses the correlation judgment module 43 to judge whether to output the candidate set to the rear Stage Noise Estimation Module 5. When the correlation is high, it indicates that the candidate set may carry a physical downlink control channel; and when the correlation is low, it indicates that the location of the candidate set may be noise or has nothing to do with the local physical downlink control channel, and then the The candidate set is discarded, the subsequent steps such as noise estimation are skipped, and the process of blind detection for the next candidate set is directly transferred.

In one embodiment, it also includes a soft bit discrimination module 61, the input end of the soft bit discrimination module 61 is connected to the signal matrix module 6, the 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 used to judge whether to input the candidate set into the polar code decoding module 7;

Soft bit discrimination module 61 comprises:

Soft bit extraction module 611, the soft bit extraction module 611 extracts soft bit information from the candidate set after the self-solution signal matrix;

A modulation information generation module 612, the modulation information generation module 612 is connected to the soft bit extraction module 611, and the modulation information generation module 612 generates modulation signal information according to the soft bit information;

The comparison module 613 is connected to the modulation information generation module 612 , and the comparison module 613 judges whether to input the candidate set into the polar code decoding module 7 according to the modulation information and the preset modulation signal threshold.

The modulation information generating module 612 accumulates multiple numerical values to be mapped to constellation points in the soft bit information to obtain modulation signal information.

Specifically, in the prior art, it is necessary to carry out the process of signal extraction, channel estimation, noise estimation, MIMO solution, and polar code decoding one by one and cyclically for several candidate sets before it can be judged according to the decoding result Whether the current candidate set contains the relevant information of the physical downlink control channel, its processing takes a long time and the problem of low efficiency, in this embodiment, the polar code decoding module 7. Add a soft bit discrimination module 61 in the front stage, extract soft bit information from the candidate set through the soft bit extraction module 611, and use the modulation information generation module 612 as the modulation signal information based on the cumulative value of the numerical value mapped to the constellation point in the soft bit information , so that the comparison module 613 can compare according to the pre-built modulation signal threshold; when the cumulative value of the values is small, it can generally be considered that the candidate set contains more signal and noise components, the interference signal is strong, or the signal energy is too low, As a result, the mappable values obtained by solving MIMO are less, and then it is determined that the candidate set cannot be used for decoding to obtain the corresponding physical downlink control channel, and it is directly converted to blind detection for the next candidate set, which reduces the subsequent polar code decoding. A step of.

The above are only preferred embodiments of the present invention, and are not intended to limit the implementation and protection scope of the present invention. For those skilled in the art, they should be able to realize the equivalent replacement and The solutions obtained by obvious changes shall all be included in the protection scope of the present invention.

Claims (10)

1. A physical downlink control channel blind detection method of a 5G NR system is characterized by comprising the following steps:

step S1: acquiring a plurality of candidate sets to be detected in a search space;

step S2: selecting one candidate set;

step S3: extracting demodulation reference signals from the candidate set in the channel estimation process aiming at the candidate set, carrying out correlation calculation on the demodulation reference signals and a local reference sequence to obtain a correlation result, and judging whether the candidate set contains a physical downlink control channel according to the correlation result;

if yes, turning to step S4;

if not, returning to the step S2 to acquire the new candidate set;

step S4: sequentially performing noise estimation, signal matrix decomposition and polarization code decoding according to the screened candidate set to obtain a decoding result corresponding to the candidate set, and judging whether the candidate set contains the physical downlink control channel according to the decoding result;

if yes, outputting the candidate set;

if not, returning to the step S2 to acquire the new candidate set.

2. The blind detection method according to claim 1, characterized in that after performing the step S2, a signal energy screening process is further included before performing the step S3, the signal energy screening process being used to determine whether the candidate set contains the physical downlink control channel, and the step S3 is performed only on the candidate set containing the physical downlink control channel;

the signal energy screening process comprises the following steps:

step A1: calculating signal energy in a frequency domain location for the candidate set;

step A2: comparing the signal energy with a preset signal energy threshold value, and judging whether the signal energy is larger than the signal energy threshold value or not;

if yes, turning to the step S3;

if not, returning to the step S2 to acquire the new candidate set.

3. The method for blind detection of physical downlink control channels according to claim 1, wherein the step S3 includes:

step S31: performing channel estimation on the candidate set to obtain an estimation result;

step S32: filtering the estimation result to obtain the demodulation reference signal;

step S33: performing autocorrelation analysis on the demodulation reference signal and the reference sequence to obtain a correlation result;

step S34: comparing the correlation result with a preset correlation threshold value to judge whether the correlation result is larger than the correlation threshold value

If yes, turning to step S4;

if not, returning to the step S2 to acquire the new candidate set.

4. The blind detection method according to claim 1, further comprising a soft bit discriminating process after performing the signal matrix decoding and before performing the polar code decoding, wherein the soft bit discriminating process is used for judging whether the candidate set after the signal matrix decoding contains the physical downlink control channel and performing polar code decoding only on the candidate set containing the physical downlink control channel;

the soft bit discrimination process comprises the following steps:

step B1: extracting soft bit information from the candidate set;

step B2: acquiring modulation signal information of the candidate set according to the soft bit information;

step B3: comparing the modulated signal information with a pre-constructed modulated signal threshold, and judging whether the modulated signal information is larger than the modulated signal threshold;

if yes, decoding the candidate set;

if not, returning to the step S2 to acquire the new candidate set.

5. The blind detection method of the physical downlink control channel according to claim 4, wherein in the step B2, the method for generating the modulated signal information includes:

and determining a plurality of values to be mapped to constellation points from the soft bit information, and accumulating all the values to be mapped to obtain the modulation signal information.

6. A physical downlink control channel blind detection system of a 5G NR system, which is configured to implement a physical downlink control channel blind detection method according to any one of claims 1 to 5;

the physical downlink control channel blind detection system comprises:

the validity verification module acquires a plurality of candidate sets to be detected in the search space;

the candidate set extraction module is connected with the validity verification module and is used for selecting one candidate set from a plurality of candidate sets to be detected;

the channel estimation module is connected with the candidate set extraction module and is used for carrying out channel estimation on the candidate set;

the correlation calculation module is connected with the channel estimation module, extracts demodulation reference signals from the candidate set, carries out correlation calculation on the demodulation reference signals and a local reference sequence to obtain a correlation result, and judges whether the candidate set is allowed to pass or not according to the correlation result;

the noise estimation module is connected with the correlation calculation module and carries out noise estimation on the candidate set output by the correlation calculation module;

the signal matrix solving module is connected with the noise estimation module and used for carrying out signal matrix solving on the candidate set according to the output result of the noise estimation output module;

and the polarization code decoding module is connected with the signal matrix decoding module and decodes the candidate set after the signal matrix is decoded, so as to obtain the physical downlink control channel according to the decoding result.

7. The physical downlink control channel blind test system of claim 6, further comprising:

the input end of the signal energy screening module is connected with the candidate set extraction module, the output end of the signal energy screening module is connected with the channel estimation module, and the signal energy screening module is used for judging whether to output the candidate set to the channel estimation module;

the signal energy screening module comprises:

a signal energy calculation module that calculates signal energy in a frequency domain location for the candidate set;

and the signal energy judgment module compares the signal energy with a preset signal energy threshold value to judge whether to output the candidate set to the channel estimation module.

8. The blind detection system of claim 6 wherein the correlation calculation module comprises:

the filtering module is used for receiving the estimation result output by the channel estimation module and filtering the estimation result to obtain the demodulation reference signal;

the correlation calculation module generates a correlation result according to the demodulation reference signal and the reference sequence;

and the correlation judgment module is connected with the correlation calculation module and judges whether the candidate set is allowed to pass or not according to the correlation result.

9. The blind detection system of claim 6 further comprising a soft bit discrimination module, wherein an input end of the soft bit discrimination module is connected to the signal matrix decoding 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;

the soft bit discriminating module includes:

the soft bit extraction module extracts soft bit information from the candidate set after the signal matrix is decoded;

the modulation information generation module is connected with the soft bit extraction module and generates modulation signal information according to the soft bit information;

the comparison module is connected with the modulation information generation module and judges whether the candidate set is input into the polar code decoding module according to the modulation information and a preset modulation signal threshold.

10. The blind detection system of claim 9 wherein the modulation information generation module accumulates a plurality of values to be mapped to constellation points in the soft bit information to obtain the modulation signal information.

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