Disclosure of Invention
The invention provides a method and a system for identifying a downlink transmission mode, which are used for solving the defect that the transmission mode of a downlink channel between UE and eNodeB can not be identified when signaling is encrypted after a security mode is established between the UE and the eNodeB in the prior art.
In a first aspect, the present invention provides a method for identifying a downlink transmission mode, including:
acquiring a DCI set of downlink control information to be processed and an initial Transmission Mode (TM) parameter, and judging and identifying any DCI in the DCI set to be processed based on the TM parameter;
if judging that any DCI has a plurality of TM modes in a single antenna mode, carrying out preset optimal transmission mode identification by adopting preset double periods to obtain a first determined transmission mode, otherwise, carrying out transmission mode identification according to common DCI to obtain a second determined transmission mode;
if judging that the multiple TM modes exist in the dual-antenna mode of any DCI, performing frequency offset estimation based on a preset appointed transmission mode to obtain a third determined transmission mode.
In one embodiment, acquiring a set of downlink control information DCI to be processed, and an initial transmission mode TM parameter, and performing, based on the TM parameter, judgment and identification on any DCI in the set of DCI to be processed includes:
after the initial network connection is established, acquiring the TM parameter in the PDSCH configuration of a physical downlink shared channel from the RRCConnection setup of the radio resource control connection;
acquiring a downlink transmission signal, and performing AD conversion, digital mixing, extraction filtering, cell synchronization, channel equalization, physical Downlink Control Channel (PDCCH) demodulation, DCI blind detection and DCI screening on the downlink transmission signal to acquire the DCI set to be processed;
Determining a first preset format transmission mode and a second preset format transmission mode in the TM parameters, and judging the transmission mode of any DCI based on the first preset format transmission mode or the second preset format transmission mode.
In one embodiment, if it is determined that the multiple TM modes exist in the single antenna mode in any DCI, performing a preset preferred transmission mode identification with a preset dual period to obtain a first determined transmission mode, and otherwise performing transmission mode identification according to a common DCI to obtain a second determined transmission mode, including:
if judging that the any DCI does not have a plurality of TM modes, judging that the any DCI is common DCI;
determining a resource block RB based on the common DCI to extract a PDSCH demodulation symbol, performing PDSCH demodulation decoding, performing analysis attempt on a bit code stream obtained by decoding, extracting an initial TM mode in the RRCConnection setup message if the RRCConnection setup message is obtained by analysis, and otherwise, processing the next DCI;
and judging whether transmission mode identification is needed or not according to the initial TM mode and the cell bandwidth information, and if so, processing the next DCI.
In one embodiment, if it is determined that the multiple TM modes exist in the single antenna mode in any DCI, performing a preset preferred transmission mode identification with a preset dual period to obtain a first determined transmission mode, or performing transmission mode identification according to a common DCI to obtain a second determined transmission mode, and further including:
If judging that a plurality of TM modes exist in any DCI in a single antenna mode, determining that the initial TM mode is a transmission diversity mode TM2 or a transmission diversity mode TM3, and determining a format1 format transmission mode identification starting mark;
if the format1 format transmission mode identification starting mark is judged to be started, judging whether the format1 format transmission mode identification process is finished, if not, entering the format1 format transmission mode identification process, and if so, processing the identification result on any DCI;
determining a first statistical period and a second statistical period, respectively acquiring a first format1 analysis number and a first Cyclic Redundancy Check (CRC) passing number based on a single antenna port transmission mode (TM 1) in the first statistical period, and acquiring a second format1 analysis number and a second Cyclic Redundancy Check (CRC) passing number based on a single stream wave speed shaping mode (TM 7) in the second statistical period;
if the first Cyclic Redundancy Check (CRC) passing number is larger than the second Cyclic Redundancy Check (CRC) passing number, determining that a format1 optimal transmission mode is TM1, otherwise, TM2, if the first Cyclic Redundancy Check (CRC) passing number and the second Cyclic Redundancy Check (CRC) passing number are both 0, and the first format1 analysis number and the second format1 analysis number exceed a preset threshold, determining that a format1 format does not exist, otherwise, continuing to identify the format1 format transmission mode.
In one embodiment, if it is determined that multiple TM modes exist in the dual antenna mode in any DCI, performing frequency offset estimation based on a preset specified transmission mode to obtain a third determined transmission mode, including:
if the format2a and format2b format transmission modes are judged to be enabled, analyzing any DCI based on the format2b format to acquire demodulation reference signal (DMRS) scrambling codes and RB resource information occupied by a PDSCH;
extracting a channel pre-estimated value at a DMRS symbol of a user corresponding to any DCI from a cell rank beamforming channel pre-estimated result based on the DMRS scrambling code and the RB resource information, and taking a front half frame value and a rear half frame value of the channel pre-estimated value as downlink frequency offset estimated values;
if the downlink frequency offset estimation value is smaller than the preset frequency offset threshold value, the current subframe of the user corresponding to any DCI is judged to adopt a double-current wave speed shaping mode TM8, and channel equalization, demodulation and decoding of the current subframe of the user are to be completed, and the next DCI is processed.
In one embodiment, if it is determined that the multiple TM modes exist in the dual antenna mode in any DCI, performing frequency offset estimation based on a preset specified transmission mode to obtain a third determined transmission mode, further including:
If the format2a and format2b format transmission modes are not started, analyzing any DCI based on the format2a format;
and carrying out channel equalization, demodulation and decoding on the current sub-frame of the user corresponding to any DCI according to an open-loop spatial multiplexing mode TM3, and finishing post-processing of the next DCI.
In a second aspect, the present invention further provides a system for identifying a downlink transmission mode, including:
the acquisition module is used for acquiring a DCI set of downlink control information to be processed and an initial Transmission Mode (TM) parameter, and judging and identifying any DCI in the DCI set to be processed based on the TM parameter;
the first judging module is used for carrying out preset optimal transmission mode identification by adopting preset double periods if judging that a plurality of TM modes exist in any DCI in a single antenna mode, so as to obtain a first determined transmission mode, or carrying out transmission mode identification according to common DCI, so as to obtain a second determined transmission mode;
and the second judging module is used for carrying out frequency offset estimation based on a preset appointed transmission mode to obtain a third confirmed transmission mode if judging that any DCI has a plurality of TM modes in the dual-antenna mode.
In a third aspect, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor, where the processor implements the steps of any one of the downlink transmission mode identification methods described above when the program is executed by the processor.
In a fourth aspect, the present invention also provides a non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the steps of a downlink transmission mode identification method as described in any of the above.
In a fifth aspect, the present invention also provides a computer program product comprising a computer program which, when executed by a processor, implements the steps of a method for downlink transmission mode identification as described in any one of the above.
The downlink transmission mode identification method and system provided by the invention are based on the analysis of the air interface signals of the actual base station, and a rapid identification scheme is provided through mode analysis statistics and channel estimation, so that the PDSCH analysis rate is improved while the number of monitoring users is not reduced.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention is mainly applied to the field of wireless signal analysis, when a security mode command is established between UE and eNodeB, and signaling is encrypted and can not be analyzed, and reconfiguration information issued by a network changes the scene of a transmission mode of a special channel of the UE, under the scene, DCI information with the same length corresponds to various interpretation conditions (under the environment of a double-antenna base station, DCI format1 has different meanings under different transmission modes (TM 1 and TM 7) and corresponds to different PDSCH demodulation methods, format2a and format2b correspond to different transmission modes (TM 3 and TM 8) and correspond to different PDSCH demodulation methods, but the DCI length of blind selection is the same), when the same DCI can be subjected to various interpretation, the decoding needs to be tried for multiple times, the monitored actual user number is reduced under the limitation of hardware processing capacity, and the PDSCH decoding rate is reduced. Here, the transmission mode TM (Transmission Mode) according to the present invention is specifically classified into the following:
TM1: single antenna port transmission;
TM2: a transmission diversity mode;
TM3: an open loop spatial multiplexing mode;
TM7: a single stream wave velocity shaping mode;
TM8 dual-stream wave velocity shaping mode.
Fig. 1 is a flow chart of a downlink transmission mode identification method provided by the present invention, as shown in fig. 1, including:
s1, acquiring a DCI set of downlink control information to be processed and an initial Transmission Mode (TM) parameter, and judging and identifying any DCI in the DCI set to be processed based on the TM parameter;
s2, if judging that a plurality of TM modes exist in any DCI in a single antenna mode, carrying out preset preferred transmission mode identification by adopting preset double periods to obtain a first determined transmission mode, otherwise, carrying out transmission mode identification according to common DCI to obtain a second determined transmission mode;
and S3, if judging that the multiple TM modes exist in the dual-antenna mode of any DCI, performing frequency offset estimation based on a preset designated transmission mode to obtain a third determined transmission mode.
Specifically, the invention relates to a method for intelligently identifying a downlink transmission mode in an LTE bypass analysis system, which comprises the steps of firstly carrying out time-sharing analysis statistics on PDSCH of format1 according to different transmission modes (TM 1, TM 7) under a monitoring cell, and selecting a preferential selection mode corresponding to the format1 by comparing the statistical results; for the formats 2a and 2b with the same DCI length, performing channel estimation according to a wave speed shaping mode (TM 8, corresponding to the formats 2 b), judging whether the DCI is the wave speed shaping mode according to a channel estimation result, if so, performing processing according to the wave speed shaping mode (TM 8), otherwise, performing processing according to a common mode (TM 3, corresponding to the formats 2 a); the two modes are combined, and the probability of processing according to a correct mode is improved, so that the overall success rate of PDSCH decoding is improved.
When an initial network connection is established between the UE and the eNodeB, acquiring initial TM parameters in the special PDSCH configuration from the RRCConnection setup; when the value (TM 2 or TM 3) of the initial TM parameter is taken, intelligent recognition processing of the format1 is started, namely two recognition processing periods (T1 and T2) are set, the format1 is processed according to the TM1 in the period T1, the format1 is processed according to the TM7 in the period T2, corresponding analysis numbers and CRC passing numbers of the format1 are counted in the two periods, whether the format1 really exists is judged according to the analysis numbers and the CRC passing numbers, and if the format1 exists, priority interpretation is carried out according to which mode;
starting format2b identification processing according to the initial TM parameter value (TM 2 or TM 3) and the number of cell antenna ports being 2, namely generating two sets of DRMS reference signals with full bandwidth for two SCIDs (generated scrambling code numbers of demodulation reference signals in TM8 mode) in accordance with TM8 mode, taking out frequency domain symbols received at corresponding positions, and obtaining two sets of channel estimation results with full bandwidth through channel estimation processing; analyzing DCI (namely, format2a or Format2 b) with mixed length as Format2b, taking out SCID parameters and internal subdivision antenna modes (port 7, port8 and port 78) and occupying RB resources, selecting one set from two sets of channel estimation results with full bandwidth which are preprocessed according to the SCID parameters, selecting a corresponding channel estimation result according to the RB resources, correspondingly calculating the preprocessed channel estimation result according to the subdivision antenna modes to obtain a final equivalent channel estimation result which synthesizes a forming factor and air channel characteristics, carrying out frequency offset estimation according to the values of a front half frame and a rear half frame on each receiving antenna, analyzing DCI according to Format2a, and carrying out subsequent PDSCH channel equalization and demodulation decoding according to TM8 when the frequency offset estimation is smaller than a threshold value, otherwise, carrying out subsequent PDSCH demodulation decoding according to TM 3.
The LTE bypass analysis system according to the present invention has a structure as shown in fig. 2, and includes: a signal data source 00, a physical layer basic processing module 10, a DCI screening and scheduling module 20 and a high-level protocol processing module 30;
the physical layer basic processing module 10 specifically includes:
cell synchronization module 11: acquiring cell synchronization points and master information block MIB information according to the designated frequency point/physical cell identifier PCI;
signal preprocessor 12: performing time-frequency conversion on the input signal by using the synchronization point, PCI and MIB information provided by the cell synchronization module, performing cell-level channel estimation by using the cell reference signal, and performing channel equalization pretreatment according to the transmission diversity and the spatial multiplexing mode;
DCI blind detector 13: extracting PDCCH channel data from the preprocessed transmission diversity data, and performing DCI blind detection;
PDSCH demodulation decoder 14: extracting corresponding PDSCH channel symbol data from the preprocessing transmission diversity or the space multiplexing data according to the scheduled DCI, or directly using the preprocessing fft data and the channel estimation information to perform channel equalization to obtain the PDSCH channel symbol data, performing PDSCH demodulation decoding, and estimating P_A in the demodulation decoding process;
P_a estimator 15: according to the scheduled DCI and the user initial transmission mode, the P_A estimation output by the PDSCH demodulation decoder adjusts the P_A parameter, and improves the PDSCH high-order demodulation performance;
the DCI screening scheduling module 20 specifically includes:
DCI screener 21: performing DCI de-duplication and screening high suspected users according to the condition priority;
DCI interpreter 22: analyzing DCI information in different modes according to different lengths, directly sending the DCI without length ambiguity to a scheduler for processing, and respectively sending the DCI information to corresponding modules according to the lengths for identification processing if the DCI information is ambiguous;
FormAT1 identifier 23: determining which transmission mode (TM 1 or TM 7) is represented by FORMAT 1;
FormAT2a/FormAT2b identifier 24: determining how the DCI interprets (FORMAT 2a under TM3 or FROAMT2b under TM 8);
DCI scheduler 25: controlling a PDSCH demodulation decoder to perform demodulation and decoding, and controlling the overall load;
the higher-layer protocol processing module 30 specifically includes:
BIT level parsing and channel extraction (MAC/RLC/PDCP) 31: bit-level decoding is carried out on different channels, and logical channel PAYLOAD information (including unencrypted and encrypted information) is extracted;
RRC resolver 32: performing protocol analysis on the RRC layer such as unencrypted SIB, RRCConnectionSetup and the like to obtain cell-level parameters and user-level parameters (including information such as an initial Transmission Mode (TM), P_A and the like);
Analysis statistics 33: counting PDSCH decoding conditions;
user pattern analysis 34: and carrying out user behavior statistics according to the related information of the user logical channel PAYLOAD.
Correspondingly, in the wireless signal analysis system, when the wireless signal of the air interface is analyzed, the processes of the signal acquisition, AD conversion, digital mixing, decimation filtering, physical layer decoding, MAC, RLC, RRC, higher layer protocol analysis and the like are needed, and in the system, the physical layer decoding and protocol analysis part is mainly involved, and other parts are not described in detail.
The acquired signal data source (00) is subjected to early signal acquisition, AD conversion, digital mixing, extraction and filtering to obtain a time domain signal with the sampling rate of 30.72M, and the time domain signal is provided for the physical layer basic processing module (10) for processing.
The synchronizer (11) performs cell synchronization processing after performing down-sampling on time domain data according to the configured PCI to obtain synchronization points and MIB information;
the signal preprocessor (12) performs time-frequency conversion according to the synchronous point, PCI and MIB information, acquires a receiving end frequency domain resource grid, generates a reference signal according to PCI, performs cell-level channel estimation, performs channel equalization preprocessing on data in the receiving end frequency domain resource grid according to a channel estimation result, acquires an estimated transmitting end frequency domain resource grid (transmission diversity or space division multiplexing), and performs channel estimation precomputation on beamforming (port 7, port8 and port 78) because the reference signal position is fixed and the scrambling code scid is only two;
A DCI blind detector (13) extracts PDCCH channel data from the transmission diversity resource grid obtained by preprocessing, carries out DCI blind detection, and sends the obtained DCI information to a DCI screening and scheduling module (20) for screening, analysis and scheduling;
the PDSCH demodulation decoding module (14) performs actual demodulation decoding processing according to the DCI information provided by the DCI scheduler (25):
PDSCH symbol data may be extracted directly from the preprocessed equalization data (transmission diversity or spatial multiplexing resource grid) without using wave velocity shaping, demodulated and decoded,
for (FORMAT1@TM7) adopting port5 wave speed shaping, extracting a PDSCH receiving end signal from a receiving end frequency domain resource grid, generating a corresponding DMRS to perform channel estimation, channel equalization and demodulation decoding, and for (FORMAT 2 b) adopting (port 7, port8 and port 78) wave beam shaping, extracting the PDSCH receiving end signal and the preprocessed channel estimation from the receiving end frequency domain resource grid to perform channel equalization and demodulation decoding.
The method for intelligently identifying the transmission mode can still effectively decode the PDSCH signal when the parameters in RRC reconfiguration cannot be analyzed, improves the analysis rate of PDSCH, has the advantages of simple realization, good real-time performance, low system overhead and good identification effect, and has very high practical value.
Based on the above embodiment, the method step S1 includes:
after the initial network connection is established, acquiring the TM parameter in the PDSCH configuration of a physical downlink shared channel from the RRCConnection setup of the radio resource control connection;
acquiring a downlink transmission signal, and performing AD conversion, digital mixing, extraction filtering, cell synchronization, channel equalization, physical Downlink Control Channel (PDCCH) demodulation, DCI blind detection and DCI screening on the downlink transmission signal to acquire the DCI set to be processed;
determining a first preset format transmission mode and a second preset format transmission mode in the TM parameters, and judging the transmission mode of any DCI based on the first preset format transmission mode or the second preset format transmission mode.
Specifically, as shown in fig. 3, in step S100, after operations such as signal acquisition, AD conversion, digital mixing, decimation filtering, cell synchronization, channel estimation, channel equalization, pdcch demodulation, DCI blind detection, DCI screening, etc., a DCI set to be processed is obtained;
for each piece of DCI in the DCI set, as illustrated in step S101, it is determined whether there is ambiguity interpretation (i.e. format1 has two interpretations, i.e. TM1 and TM7, format2a and format2b have the same information length and different interpretation meanings in the dual-antenna cell), if not, other common DCI information is skipped to S102; if yes, jump to 107 for specific analysis.
The invention determines the analysis format under the single antenna or double antenna mode through the pre-processing of the signal, and is convenient for the subsequent recognition of the transmission mode under different analysis formats.
Based on any of the above embodiments, the method step S2 includes:
if judging that the any DCI does not have a plurality of TM modes, judging that the any DCI is common DCI;
determining a resource block RB based on the common DCI to extract a PDSCH demodulation symbol, performing PDSCH demodulation decoding, performing analysis attempt on a bit code stream obtained by decoding, extracting an initial TM mode in the RRCConnection setup message if the RRCConnection setup message is obtained by analysis, and otherwise, processing the next DCI;
and judging whether transmission mode identification is needed or not according to the initial TM mode and the cell bandwidth information, and if so, processing the next DCI.
Specifically, as shown in fig. 3, step S102, extracting PDSCH demodulation symbols according to the rb resource indicated by the normal dci information, and performing PDSCH demodulation decoding;
step S103, analyzing the bit code stream decoded in the step S102 to see whether the bit code stream is RRCConnection setup message, if yes, jumping to the step S104, if not, jumping to the step S102, and continuing to process the next DCI;
Step S104, deeply analyzing RRCConnection setup, extracting an initial transmission mode TM in the RRCConnection setup message;
step S105, judging whether the intelligent recognition of the transmission mode is needed according to the acquired initial transmission mode TM and the cell bandwidth information, if not, jumping to step S102, and continuing to process the next DCI.
The invention has the characteristics of simple realization, good real-time performance, small system overhead and good recognition effect.
Based on any of the above embodiments, the method step S2 further includes:
if judging that a plurality of TM modes exist in any DCI in a single antenna mode, determining that the initial TM mode is a transmission diversity mode TM2 or a transmission diversity mode TM3, and determining a format1 format transmission mode identification starting mark;
if the format1 format transmission mode identification starting mark is judged to be started, judging whether the format1 format transmission mode identification process is finished, if not, entering the format1 format transmission mode identification process, and if so, processing the identification result on any DCI;
determining a first statistical period and a second statistical period, respectively acquiring a first format1 analysis number and a first Cyclic Redundancy Check (CRC) passing number based on a single antenna port transmission mode (TM 1) in the first statistical period, and acquiring a second format1 analysis number and a second Cyclic Redundancy Check (CRC) passing number based on a single stream wave speed shaping mode (TM 7) in the second statistical period;
If the first Cyclic Redundancy Check (CRC) passing number is larger than the second Cyclic Redundancy Check (CRC) passing number, determining that a format1 optimal transmission mode is TM1, otherwise, TM2, if the first Cyclic Redundancy Check (CRC) passing number and the second Cyclic Redundancy Check (CRC) passing number are both 0, and the first format1 analysis number and the second format1 analysis number exceed a preset threshold, determining that a format1 format does not exist, otherwise, continuing to identify the format1 format transmission mode.
Specifically, as shown in fig. 3, in step S106, if the initial transmission mode is TM2 or TM3, a format1 format transmission mode identification start flag is set; if the initial transmission mode is TM2 or TM3 and the number of cell antenna ports is 2, setting a format2a/format2b format transmission mode identification starting mark; after the setting, the process goes to step S102 to continue the processing of the next DCI.
Step S107, judging whether the dci information is in format1 format, if yes, jumping to S108 to continue processing; if not, the process proceeds to step S118 to continue the process.
Step S108, if the format1 format transmission mode identification starting identification is set, jumping to step S109; if not, the process proceeds to step S117.
Step S109, judging whether the format1 format transmission mode identification process is finished, if not, jumping to S110 to start the format1 format transmission mode identification process; if so, the process goes to S116 to perform subsequent processing according to the recognition result.
Step S110, format1 format transmission mode identification is identified by using a statistical method, and two statistical periods T1 and T2 are set;
step S111, in the period T1, the format1 format carries out CRC passing number according to the transmission mode TM1;
step S112, in the period T2, the format1 format is interpreted according to the transmission mode TM7, corresponding PDSCH channel equalization, demodulation and decoding are carried out, and the analysis number and CRC passing number of the format1 are obtained;
step S113, comparing the format1 analysis number and CRC passing number in the period T1 and the period T2, if the passing rate in the period T1 is larger than the passing rate in the period T2, determining that the format1 is preferable to be transmitted in the transmission mode of TM1; if the passing rate in the period T2 is larger than the passing rate in the period T1, judging that the format1 is in a TM7 optimal transmission mode; if the CRC passing number is 0 in two periods and the analysis number exceeds a set threshold, judging that the format1 format does not exist; otherwise, the process jumps to S110, and format1 format transmission mode recognition is continued.
Step S114, judging whether the format1 format transmission mode identification process result generates a valid result, if yes (namely, finishing judgment), jumping to S115 to finish the identification process; if not, the process goes to S110 to continue the format1 format transmission mode recognition.
Step S116, performing corresponding processing on format1 format DCI by using the judging result, and performing PDSCH demodulation and decoding according to TM1 if the preferred transmission mode is TM 1; if the preferred transmission mode is TM7, performing PDSCH channel equalization, demodulation and decoding according to the TM7 mode; if the format1 format is determined not to exist, the PDSCH demodulation and decoding processing procedure is skipped. After the process is completed, the process jumps to step S102, where the process continues with the next DCI.
Step S117, PDSCH demodulation and decoding is performed according to TM1, and after the processing is completed, the process jumps to step S102, and the next DCI is continued to be processed.
When the parameters in RRC reconfiguration cannot be analyzed, the invention can still effectively decode the PDSCH signals, and improves the analysis rate of the PDSCH.
Based on any of the above embodiments, the method step S3 includes:
if the format2a and format2b format transmission modes are judged to be enabled, analyzing any DCI based on the format2b format to acquire demodulation reference signal (DMRS) scrambling codes and RB resource information occupied by a PDSCH;
Extracting a channel pre-estimated value at a DMRS symbol of a user corresponding to any DCI from a cell rank beamforming channel pre-estimated result based on the DMRS scrambling code and the RB resource information, and taking a front half frame value and a rear half frame value of the channel pre-estimated value as downlink frequency offset estimated values;
if the downlink frequency offset estimation value is smaller than the preset frequency offset threshold value, the current subframe of the user corresponding to any DCI is judged to adopt a double-current wave speed shaping mode TM8, and channel equalization, demodulation and decoding of the current subframe of the user are to be completed, and the next DCI is processed.
Specifically, as shown in fig. 3, in step S118, it is determined whether a format2a/format2b format transmission mode identification start flag is set, if yes, the process goes to step S119 to perform heuristic identification; if not, the process proceeds to S124.
Step S119, the DCI is parsed according to format2b to obtain DMRS scrambling code (scid) and RB resource information occupied by PDSCH;
step S120, extracting the channel pre-estimation value of the DCI corresponding to the user' S DMRS symbol from the cell-level beam-forming channel pre-estimation result output by the channel pre-processor according to the DMRS scrambling code (scid) and RB resource information (the DRMS signal transmitted on each transmitting antenna port under TM8 has orthogonality, and when receiving, the orthogonality can be utilized, the DMRS signal on port 0 can be directly used for channel pre-estimation, without calculating the channel estimation specific value under each transmitting port, so as to reduce the judgment calculation amount)
Step S121, using the estimated value of the position of the DMRS obtained in step S120, the front half frame and the rear half frame have values, and the estimated value can be used to estimate the frequency offset of the downlink transmitting end
Step S122, comparing the frequency offset estimation value with a set frequency offset threshold value, if the frequency offset estimation value is smaller than the set frequency offset threshold value, judging that the DCI corresponds to the current subframe of the user and uses a TM8 transmission mode, and jumping to S123 for subsequent processing; otherwise, determining that the DCI corresponds to the current subframe of the user and uses the TM3 transmission mode, and jumping to S124 for subsequent processing.
Step S123, corresponding PDSCH channel equalization and demodulation decoding are carried out according to TM8, after the processing is completed, the step S102 is skipped, and the next DCI is continuously processed.
When the parameters in RRC reconfiguration cannot be analyzed, the invention can still effectively decode the PDSCH signals, and improves the analysis rate of the PDSCH.
Based on any of the above embodiments, the method step S3 further includes:
if the format2a and format2b format transmission modes are not started, analyzing any DCI based on the format2a format;
and carrying out channel equalization, demodulation and decoding on the current sub-frame of the user corresponding to any DCI according to an open-loop spatial multiplexing mode TM3, and finishing post-processing of the next DCI.
Specifically, as shown in fig. 3, in the last step S124, the DCI is reinterpretated according to format2a, PDSCH demodulation and decoding is performed according to TM3, and after the processing is completed, the process jumps to step S102, and the next DCI is continued to be processed.
The method has the advantages of simple realization and good real-time performance, and has very high practical value in LTE wireless signal analysis products.
The downlink transmission mode identification system provided by the invention is described below, and the downlink transmission mode identification system described below and the downlink transmission mode identification method described above can be referred to correspondingly.
Fig. 4 is a schematic structural diagram of a downlink transmission mode identification system provided by the present invention, as shown in fig. 4, including: acquisition module 41, first judgment module 42, and second judgment module 43
The acquiring module 41 is configured to acquire a downlink control information DCI set to be processed and an initial transmission mode TM parameter, and determine and identify any DCI in the DCI set to be processed based on the TM parameter; the first judging module 42 is configured to, if it is judged that multiple TM modes exist in the single antenna mode of any DCI, perform a preset preferred transmission mode identification with a preset dual period to obtain a first determined transmission mode, or perform a transmission mode identification according to a common DCI to obtain a second determined transmission mode; the second determining module 43 is configured to, if it is determined that the multiple TM modes exist in the dual-antenna mode in any DCI, perform frequency offset estimation based on a preset designated transmission mode, and obtain a third determined transmission mode.
The system for intelligently identifying the transmission mode can still effectively decode the PDSCH signal when the parameters in RRC reconfiguration cannot be analyzed, improves the analysis rate of PDSCH, has the advantages of simple realization, good instantaneity, low system overhead and good identification effect, and has very high practical value.
Fig. 5 illustrates a physical schematic diagram of an electronic device, as shown in fig. 5, which may include: processor 510, communication interface (Communications Interface) 520, memory 530, and communication bus 540, wherein processor 510, communication interface 520, memory 530 complete communication with each other through communication bus 540. Processor 510 may invoke logic instructions in memory 530 to perform a downstream transmission mode identification method comprising: acquiring a DCI set of downlink control information to be processed and an initial Transmission Mode (TM) parameter, and judging and identifying any DCI in the DCI set to be processed based on the TM parameter; if judging that any DCI has a plurality of TM modes in a single antenna mode, carrying out preset optimal transmission mode identification by adopting preset double periods to obtain a first determined transmission mode, otherwise, carrying out transmission mode identification according to common DCI to obtain a second determined transmission mode; if judging that the multiple TM modes exist in the dual-antenna mode of any DCI, performing frequency offset estimation based on a preset appointed transmission mode to obtain a third determined transmission mode.
Further, the logic instructions in the memory 530 described above may be implemented in the form of software functional units and may be stored in a computer-readable storage medium when sold or used as a stand-alone product. Based on this understanding, the technical solution of the present invention may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution, in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server, a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or other various media capable of storing program codes.
In another aspect, the present invention also provides a computer program product, the computer program product including a computer program, the computer program being storable on a non-transitory computer readable storage medium, the computer program, when executed by a processor, being capable of executing the downlink transmission mode identifying method provided by the above methods, the method comprising: acquiring a DCI set of downlink control information to be processed and an initial Transmission Mode (TM) parameter, and judging and identifying any DCI in the DCI set to be processed based on the TM parameter; if judging that any DCI has a plurality of TM modes in a single antenna mode, carrying out preset optimal transmission mode identification by adopting preset double periods to obtain a first determined transmission mode, otherwise, carrying out transmission mode identification according to common DCI to obtain a second determined transmission mode; if judging that the multiple TM modes exist in the dual-antenna mode of any DCI, performing frequency offset estimation based on a preset appointed transmission mode to obtain a third determined transmission mode. In yet another aspect, the present invention also provides a non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, is implemented to perform the method for identifying a downlink transmission mode provided by the above methods, the method comprising: acquiring a DCI set of downlink control information to be processed and an initial Transmission Mode (TM) parameter, and judging and identifying any DCI in the DCI set to be processed based on the TM parameter; if judging that any DCI has a plurality of TM modes in a single antenna mode, carrying out preset optimal transmission mode identification by adopting preset double periods to obtain a first determined transmission mode, otherwise, carrying out transmission mode identification according to common DCI to obtain a second determined transmission mode; if judging that the multiple TM modes exist in the dual-antenna mode of any DCI, performing frequency offset estimation based on a preset appointed transmission mode to obtain a third determined transmission mode.
The apparatus embodiments described above are merely illustrative, wherein the elements illustrated as separate elements may or may not be physically separate, and the elements shown as elements may or may not be physical elements, may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art will understand and implement the present invention without undue burden.
From the above description of the embodiments, it will be apparent to those skilled in the art that the embodiments may be implemented by means of software plus necessary general hardware platforms, or of course may be implemented by means of hardware. Based on this understanding, the foregoing technical solution may be embodied essentially or in a part contributing to the prior art in the form of a software product, which may be stored in a computer readable storage medium, such as ROM/RAM, a magnetic disk, an optical disk, etc., including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the method described in the respective embodiments or some parts of the embodiments.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.