Signal processing method and system

Abstract

The present invention provides a signal processing method and system, including: despreading the PSDU part of the zigbee signal after MSK demodulation, and each zigbee signal is independently despread to avoid the introduction of correlation errors between the two when converting from MSK to O-QPSK, and to avoid the ambiguity caused by the threshold selection when the sampling points are merged. By storing pre-transcoding and similarity soft decision calculation to despread the PSDU part of the zigbee baseband signal after MSK demodulation, the following two purposes can be achieved at the same time: 1) Avoid the introduction of errors due to the correlation between the previous and next chips when converting from MSK to O-QPSK. 2) Avoid the ambiguity caused by the threshold selection when the sampling points are merged; since the two technical problems are solved at the same time, the present invention achieves an unexpected technical effect.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a signal processing method and system. Background Art

[0002] The existing methods for receiving 2.4G zigbee signals after down-conversion include: directly demodulating the O-QPSK signal, or for compatibility with Bluetooth BLE, performing MSK demodulation, then merging the sampling points, and performing MSK to O-QPSK transcoding to obtain the zigbee chip code, and then despreading.

[0003] However, when converting from MSK to O-QPSK, the previous and next chips are correlated, which introduces errors. In addition, ambiguity will occur due to the threshold selection when merging sampling points. Summary of the invention

[0004] The object of the present invention is to provide a signal processing method and system to solve the problem of error introduced during the existing MSK to O-QPSK conversion and ambiguity caused by threshold selection during sampling point merging.

[0005] In order to solve the above technical problems, the present invention provides a signal processing method, comprising:

[0006] The PSDU part of the zigbee signal after MSK demodulation is despread, and each zigbee signal is despread independently to avoid the correlation error between the two when converting from MSK to O-QPSK, and to avoid the ambiguity caused by the threshold selection when merging sampling points.

[0007] Optionally, the signal processing method further includes:

[0008] By storing pre-transcoding and similarity soft decision calculation, the PSDU part of the zigbee baseband signal after MSK demodulation is despread to avoid the error introduced by the correlation between the previous and next chips when converting from MSK to O-QPSK, and to avoid the ambiguity caused by the threshold selection when merging sampling points.

[0009] Optionally, the signal processing method further includes:

[0010] The zigbee baseband signal is processed by the receiver based on MSK demodulation, including:

[0011] The zero-IF zigbee baseband signal undergoes low-pass filtering, MSK demodulation, frame synchronization, frequency offset compensation, header information extraction, PSDU despreading, and symbol-to-bit conversion.

[0012] Optionally, in the signal processing method, in order to improve the overall sensitivity of the receiver of MSK demodulation, PSDU despreading includes:

[0013] Through mathematical derivation of O-QPSK and MSK, the coding table is obtained;

[0014] The receiver samples the 2M / s Zigbee chip bit signal 16 times at a rate of 32M / s;

[0015] The first sampling point of PSDU is obtained through the frame synchronization module;

[0016] Starting from the first sampling point, count the number of sampling points with signal amplitude greater than 0 in every 16 sampling points, and get the value X;

[0017] Similarly, 32 groups of 16 sampling points are calculated, and X1 to X32 are obtained, with a value range of [0,16].

[0018] Optionally, the signal processing method further includes:

[0019] Calculate the similarities S0~S15 with sym0~sym15 respectively, compare S0~S15, and take the sym corresponding to the minimum value among S0~S15;

[0020] Calculating the similarity S0~S15 with sym0~sym15 respectively includes:

[0021] Determine whether chip[n] is 1. If so, calculate |16-Xn|. Otherwise, calculate |Xn-0| to get Yn.

[0022] Find the sum of Y1~Y31 and get the similarity S0 of sym0.

[0023] Optionally, the signal processing method further includes:

[0024] Use X1 to X32 to perform the following similarity calculations on 0000 to 1111. 0000 corresponds to the signal Sym0, and so on for Sym0 to Sym15. Take Sym0 as an example:

[0025] If chip[n] corresponding to Sym0 is 1, then calculate |16-Xn| and get Yn;

[0026] If chip[n] corresponding to Sym0 is 0, then calculate |Xn-0| and get Yn;

[0027] Similarly, we get Y1~Y31 corresponding to the 31 bits in the chip corresponding to sym0, and then calculate the sum of Y1~Y31 to get the similarity S0 of sym0;

[0028] Use the above method to obtain S0~S15 corresponding to sym0 to sym15 respectively;

[0029] Then compare S0~S15 to get the smallest number, and its corresponding sym is the despreading result;

[0030] If there are multiple smallest numbers, take the sym with the smallest value as the despreading result.

[0031] The present invention also provides a signal processing system, comprising:

[0032] An MSK demodulation receiver configured to demodulate the zigbee signal MSK; and

[0033] The despreading module is configured to despread the PSDU part of the zigbee signal after MSK demodulation. Each zigbee signal is despread independently to avoid the correlation error between the two when converting from MSK to O-QPSK, and to avoid the ambiguity caused by the threshold selection when merging the sampling points.

[0034] Optionally, in the signal processing system, the despreading module includes:

[0035] A storage pre-transcoding module is configured to despread the PSDU part of the zigbee baseband signal after MSK demodulation through storage pre-transcoding; and

[0036] The similarity soft decision calculation module is configured to despread the PSDU part of the zigbee baseband signal after MSK demodulation through similarity soft decision calculation.

[0037] Optionally, in the signal processing system, the receiver for MSK demodulation includes:

[0038] A low-pass filter module is configured to perform low-pass filtering on a zero intermediate frequency Zigbee baseband signal to be subjected to MSK demodulation; and

[0039] The MSK demodulation module is configured to perform MSK demodulation on the zero intermediate frequency Zigbee baseband signal.

[0040] Optionally, the signal processing system further includes:

[0041] The frame synchronization module is configured to perform frame synchronization processing on the zero intermediate frequency Zigbee baseband signal after MSK demodulation;

[0042] The frequency offset compensation module is configured to perform frequency offset compensation processing on the zero intermediate frequency Zigbee baseband signal after frame synchronization processing;

[0043] A header information extraction module is configured to perform header information extraction processing on a zero intermediate frequency Zigbee baseband signal after frequency offset compensation processing and before PSDU despreading processing; and

[0044] The symbol-to-bit conversion module is configured to perform symbol-to-bit conversion processing on the zero intermediate frequency Zigbee baseband signal after the PSDU despreading processing.

[0045] In the signal processing method and system provided by the present invention, the PSDU part of the zigbee baseband signal after MSK demodulation is despread by storing pre-transcoding and similarity soft decision calculation, which can achieve the following two purposes at the same time: 1) avoid the error introduced by the correlation between the previous and next chips when converting from MSK to O-QPSK. 2) avoid the ambiguity caused by the threshold selection when merging the sampling points; because the two technical problems are solved at the same time, the present invention achieves an unexpected technical effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic diagram of the overall process of a receiver processing a zigbee baseband signal based on MSK demodulation in a signal processing method according to an embodiment of the present invention;

[0047] Figure 2 It is a flow chart of using X1 to X32 to respectively calculate similarity of signals in a signal processing method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0048] The present invention will be further described below in conjunction with specific embodiments with reference to the accompanying drawings.

[0049] It should be noted that the components in the various figures may be shown exaggeratedly for the sake of illustration and are not necessarily true to scale. In the various figures, identical or functionally identical components are provided with the same reference numerals.

[0050] In the present invention, unless otherwise specified, "arranged on...", "arranged above..." and "arranged above..." do not exclude the existence of an intermediate between the two. In addition, "arranged on or above..." merely indicates the relative positional relationship between two components, and in certain cases, such as after reversing the product direction, it can also be converted into "arranged below or below...", and vice versa.

[0051] In the present invention, each embodiment is only intended to illustrate the aspects of the present invention and should not be construed as limiting.

[0052] In the present invention, unless otherwise specified, the quantifiers "a", "an" and "an" do not exclude the presence of a plurality of elements.

[0053] It should also be noted that in the embodiments of the present invention, for the sake of clarity and simplicity, only a portion of the parts or components may be shown, but those of ordinary skill in the art will understand that under the teachings of the present invention, the required parts or components may be added according to the needs of the specific scenario. In addition, unless otherwise specified, the features in different embodiments of the present invention may be combined with each other. For example, a feature in the second embodiment may be used to replace a corresponding or functionally identical or similar feature in the first embodiment, and the resulting embodiment also falls within the disclosure scope or recorded scope of the present application.

[0054] It should also be noted that within the scope of the present invention, the terms "same", "equal", "equal to" and the like do not mean that the values ​​of the two are absolutely equal, but allow a certain reasonable error, that is, the terms also cover "substantially the same", "substantially equal", "substantially equal to". By analogy, in the present invention, the terms "perpendicular to", "parallel to" and the like indicating directions also cover the meanings of "substantially perpendicular to" and "substantially parallel to".

[0055] In addition, the numbering of the steps of the methods of the present invention does not limit the execution order of the method steps. Unless otherwise specified, the method steps can be executed in different orders.

[0056] The signal processing method and system proposed by the present invention are further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer according to the following description. It should be noted that the accompanying drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0057] The object of the present invention is to provide a signal processing method and system to solve the problem of error introduced during the existing MSK to O-QPSK conversion and ambiguity caused by threshold selection during sampling point merging.

[0058] To achieve the above-mentioned purpose, the present invention provides a signal processing method and system, including: despreading the PSDU part of the zigbee signal after MSK demodulation, and independently despreading each zigbee signal to avoid the introduction of correlation error between the two when converting from MSK to O-QPSK, and to avoid the ambiguity caused by threshold selection when merging sampling points.

[0059] Figures 1-2 A first embodiment of the present invention is provided, which shows a flow chart of a signal processing method; specifically, as Figure 1 The overall framework (process or module) of the signal processing method shown in FIG. 1 includes: a receiver based on MSK demodulation for processing the zigbee baseband signal, and a despreading method for the PSDU part to improve the sensitivity of the overall receiver, such as Figure 1 As shown, specifically including:

[0060] Through the mathematical derivation of O-QPSK and MSK, the coding table is obtained, and the coding table is shown in Table 1 below:

[0061] Bin Sym Original zigbee chip Converted chip 0000 0 11011001110000110101001000101110 1100000011101111010111001101100x 0001 1 11101101100111000011010100100010 1001110000001110111101011100110x 0010 2 00101110110110011100001101010010 1101100111000000111011110101110x 0011 3 00100010111011011001110000110101 1100110110011100000011101111010x 0100 4 01010010001011101101100111000011 0101110011011001110000001110111x 0101 5 00110101001000101110110110011100 1111010111001101100111000000111x 0110 6 11000011010100100010111011011001 1110111101011100110110011100000x 0111 7 10011100001101010010001011101101 0000111011110101110011011001110x 1000 8 10001100100101100000011101111011 0011111100010000101000110010011x 1001 9 10111000110010010110000001110111 0110001111110001000010100011001x 1010 10 01111011100011001001011000000111 0010011000111111000100001010001x 1011 11 01110111101110001100100101100000 0010001001100011111100010000101x 1100 12 00000111011110111000110010010110 1010001000100110001111110001000x 1101 13 01100000011101111011100011001001 0000101000100010011000111111000x 1110 14 10010110000001110111101110001100 0001000010100010001001100011111x 1111 15 11001001011000000111011110111000 1111000100001010001100100110001x

[0062] Table 1 (Note: the x in the table depends on the correlation between the previous and next data)

[0063] The receiver of MSK demodulation samples the 2M / s Zigbee chip bit signal at 16 times the rate of 32M / s, obtains the first sampling point of PSDU through the frame synchronization module, and calculates the number of sampling points with signal amplitude greater than 0 in every 16 sampling points starting from the first sampling point, and obtains the value X. Similarly, 32 groups of 16 sampling points are calculated, each with 16 sampling points, to obtain X1~X32, with a value range of [0,16].

[0064] Use X1 to X32 to perform the following similarity calculations on the 16 items in Table 1, taking sym0 as an example:

[0065] If the chip[n] corresponding to Sym0 is 1, then calculate |16-Xn|. If the chip[n] corresponding to Sym0 is 0, then calculate |Xn-0| to get Yn. Similarly, we can get Y1~Y31 corresponding to the 31 bits in the chip corresponding to sym0, and then calculate the sum of Y1~Y31 to get the similarity S0 of sym0. Use the above method to get S0~S15 corresponding to sym0 to sym15 respectively. Then compare S0~S15 to get the smallest number, and its corresponding sym is the despreading result. If there are multiple smallest numbers, take the sym with the smallest value as the despreading result. Similar calculations are as follows Figure 2 shown.

[0066] This embodiment provides a signal processing method, including: despreading the PSDU part of the zigbee signal after MSK demodulation, and each zigbee signal is independently despread to avoid the introduction of correlation errors between the two when converting from MSK to O-QPSK, and to avoid the ambiguity caused by the threshold selection when the sampling points are merged. It also includes: despreading the PSDU part of the zigbee baseband signal after MSK demodulation by storing pre-transcoding and similarity soft decision calculation to avoid the introduction of errors due to the correlation between the front and back chips when converting from MSK to O-QPSK, and to avoid the ambiguity caused by the threshold selection when the sampling points are merged.

[0067] Specifically, the signal processing method also includes: the zigbee baseband signal is processed by a receiver based on MSK demodulation, including: the zero intermediate frequency zigbee baseband signal is sequentially subjected to low-pass filtering, MSK demodulation, frame synchronization, frequency offset compensation, header information extraction, PSDU despreading, and symbol-to-bit conversion.

[0068] Furthermore, in the signal processing method, in order to improve the overall sensitivity of the receiver of MSK demodulation, PSDU despreading includes: obtaining a coding table through mathematical derivation of O-QPSK and MSK; the receiver samples the zigbee chip bit signal of 2M / s at a rate of 32M / s by 16 times; obtaining the first sampling point of PSDU through the frame synchronization module; starting from the first sampling point, the number of sampling points with signal amplitude greater than 0 in every 16 sampling points is calculated in sequence to obtain a value X; and 32 groups of 16 sampling points are calculated in this way, each group of 16 sampling points, to obtain X1~X32, with a value range of [0,16]. Calculate the similarities S0~S15 with sym0~sym15 respectively, compare S0~S15, and take the sym corresponding to the minimum value in S0~S15; calculate the similarities S0~S15 with sym0~sym15 respectively, including: determine whether chip[n] is 1, if so, calculate |16-Xn|, otherwise calculate |Xn-0|, and get Yn; calculate the sum of Y1~Y31 to get the similarity S0 of sym0.

[0069] like Figure 2 As shown, in the signal processing method, it also includes: using X1~X32 to perform the following similarity calculation on 0000~1111 respectively, 0000 corresponds to the signal Sym0, and so on for Sym0~Sym15, taking Sym0 as an example: if the chip[n] corresponding to Sym0 is 1, then calculate |16-Xn| to obtain Yn; if the chip[n] corresponding to Sym0 is 0, then calculate |Xn-0| to obtain Yn; and so on, obtain Y1~Y31 corresponding to 31 bits in the chip corresponding to sym0, and then calculate the sum of Y1~Y31 to obtain the similarity S0 of sym0; use the above method to obtain S0~S15 corresponding to sym0 to sym15 respectively; then compare S0~S15 to obtain the smallest number, and its corresponding sym is the despreading result; if there are multiple smallest numbers, take the sym with the smallest value as the despreading result.

[0070] This embodiment also provides a signal processing system, including: an MSK demodulation receiver, configured to demodulate the zigbee signal MSK; and a despreading module, configured to despread the PSDU part of the zigbee signal after MSK demodulation, and each zigbee signal is independently despread to avoid the introduction of correlation errors between the two when converting from MSK to O-QPSK, and to avoid ambiguity caused by threshold selection when merging sampling points.

[0071] Specifically, in the signal processing system, the despreading module includes: a storage pre-transcoding module, which is configured to despread the PSDU part of the zigbee baseband signal after MSK demodulation by storing pre-transcoding; and a similarity soft decision calculation module, which is configured to despread the PSDU part of the zigbee baseband signal after MSK demodulation by similarity soft decision calculation.

[0072] Furthermore, in the signal processing system, the receiver of MSK demodulation includes: a low-pass filtering module configured to perform low-pass filtering on the zero intermediate frequency Zigbee baseband signal to be MSK demodulated; and an MSK demodulation module configured to perform MSK demodulation on the zero intermediate frequency Zigbee baseband signal.

[0073] In addition, the signal processing system also includes: a frame synchronization module, which is configured to perform frame synchronization processing on the zero intermediate frequency Zigbee baseband signal after MSK demodulation; a frequency offset compensation module, which is configured to perform frequency offset compensation processing on the zero intermediate frequency Zigbee baseband signal after frame synchronization processing; a header information extraction module, which is configured to perform header information extraction processing on the zero intermediate frequency Zigbee baseband signal after frequency offset compensation processing and before PSDU despreading processing; and a symbol-to-bit conversion module, which is configured to perform symbol-to-bit conversion processing on the zero intermediate frequency Zigbee baseband signal after PSDU despreading processing.

[0074] In the signal processing method and system provided by the present invention, the PSDU part of the zigbee baseband signal after MSK demodulation is despread by storing pre-transcoding and similarity soft decision calculation, which can achieve the following two purposes at the same time: 1) avoid the error introduced by the correlation between the previous and next chips when converting from MSK to O-QPSK. 2) avoid the ambiguity caused by the threshold selection when merging the sampling points; because the two technical problems are solved at the same time, the present invention achieves an unexpected technical effect.

[0075] In summary, the above embodiments describe in detail different configurations of the signal processing method. Of course, the present invention includes but is not limited to the configurations listed in the above embodiments. Any content that is transformed based on the configurations provided in the above embodiments belongs to the scope of protection of the present invention. Those skilled in the art can draw inferences based on the contents of the above embodiments.

[0076] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0077] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A signal processing method, characterized in that: include: By storing the pre-transcoding and similarity soft decision calculation, the PSDU part of the zigbee baseband signal after MSK demodulation is despread. in PSDU despreading includes: obtaining a coding table through mathematical derivation of O-QPSK and MSK; the receiver samples the 2M / s Zigbee chip bit signal 16 times at a rate of 32M / s; obtaining the first sampling point of PSDU through the frame synchronization module; starting from the first sampling point, the number of sampling points with signal amplitude greater than 0 in every 16 sampling points is calculated in sequence, and the value is X; and 32 groups of 16 sampling points are calculated in this way, each group of 16 sampling points, to obtain X1~X32, with a value range of [0,16]; Calculate the similarities S0 to S15 corresponding to sym0 to sym15 respectively, compare S0 to S15, and take the sym corresponding to the minimum value among S0 to S15; calculate the similarities S0 to S15 corresponding to sym0 to sym15 respectively, including: If chip[n] corresponding to Sym0 in the encoding table is 1, then calculate |16-Xn| to get Yn; If chip[n] corresponding to Sym0 in the encoding table is 0, then calculate |Xn-0| and get Yn; Similarly, we get Y1 to Y31 corresponding to the 31 bits in the chip corresponding to sym0, and then calculate the sum of Y1 to Y31 to get the similarity S0 corresponding to sym0; Use the above method to obtain the similarities S0~S15 corresponding to sym0 to sym15 respectively; Then compare S0~S15 to get the smallest number, and its corresponding sym is the despreading result; If there are multiple smallest numbers, take the sym with the smallest value as the despreading result.

2. The signal processing method according to claim 1, characterized in that: Also includes: The zigbee baseband signal is processed by the receiver based on MSK demodulation, including: The zero-IF zigbee baseband signal undergoes low-pass filtering, MSK demodulation, frame synchronization, frequency offset compensation, header information extraction, PSDU despreading, and symbol-to-bit conversion.

3. A signal processing system, characterized in that: include: The receiver of MSK demodulation is configured to demodulate the zigbee signal MSK; as well as The despreading module is configured to despread the PSDU part of the zigbee baseband signal after MSK demodulation by storing the pre-transcoding and similarity soft decision calculation, The PSDU despreading includes: obtaining a coding table through mathematical derivation of O-QPSK and MSK; the receiver samples the 2M / s Zigbee chip bit signal 16 times at a rate of 32M / s; obtaining the first sampling point of the PSDU through the frame synchronization module; starting from the first sampling point, the number of sampling points with signal amplitude greater than 0 in every 16 sampling points is calculated in sequence, and the value is X; and 32 groups of 16 sampling points are calculated in this way, each group of 16 sampling points, to obtain X1~X32, with a value range of [0,16]; Calculate the similarities S0 to S15 corresponding to sym0 to sym15 respectively, compare S0 to S15, and take the sym corresponding to the minimum value among S0 to S15; calculate the similarities S0 to S15 corresponding to sym0 to sym15 respectively, including: If chip[n] corresponding to Sym0 in the encoding table is 1, then calculate |16-Xn| to get Yn; If chip[n] corresponding to Sym0 in the encoding table is 0, then calculate |Xn-0| and get Yn; Similarly, we get Y1 to Y31 corresponding to the 31 bits in the chip corresponding to sym0, and then calculate the sum of Y1 to Y31 to get the similarity S0 corresponding to sym0; Use the above method to obtain the similarities S0~S15 corresponding to sym0 to sym15 respectively; Then compare S0~S15 to get the smallest number, and its corresponding sym is the despreading result; If there are multiple smallest numbers, take the sym with the smallest value as the despreading result.

4. The signal processing system according to claim 3, characterized in that The receiver for MSK demodulation includes: A low-pass filter module is configured to perform low-pass filtering on a zero intermediate frequency Zigbee baseband signal to be subjected to MSK demodulation; and The MSK demodulation module is configured to perform MSK demodulation on the zero intermediate frequency Zigbee baseband signal.

5. The signal processing system according to claim 4, characterized in that The receiver for MSK demodulation also includes: The frame synchronization module is configured to perform frame synchronization processing on the zero intermediate frequency Zigbee baseband signal after MSK demodulation; The frequency offset compensation module is configured to perform frequency offset compensation processing on the zero intermediate frequency Zigbee baseband signal after frame synchronization processing; A header information extraction module is configured to perform header information extraction processing on a zero intermediate frequency Zigbee baseband signal after frequency offset compensation processing and before PSDU despreading processing; and The symbol-to-bit conversion module is configured to perform symbol-to-bit conversion processing on the zero intermediate frequency Zigbee baseband signal after the PSDU despreading processing.

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