CN116346173A - MIMO signal detection and search method, decoding circuit and receiving antenna system - Google Patents

Abstract

The invention relates to a MIMO signal detection and search method, a decoding circuit and a receiving antenna system. The signal detection and search method includes the following steps. A signal search tree is obtained, and multiple candidate signals are sorted at each level of the signal search tree. At each level of the signal search tree, candidate signals are scanned sequentially. In each level of the signal search tree, if a cumulative geometric distance is greater than or equal to a threshold, the unscanned candidate signals are excluded. If the cumulative geometric distance is less than the threshold, then update the threshold with the cumulative geometric distance. When all candidate signals are calculated, an estimated signal combination is output, and the scanning of the signal search tree is ended.

Description

MIMO signal detection and search method, decoding circuit and receiving antenna system

technical field

The invention relates to a MIMO signal detection and search method, a decoding circuit and a receiving antenna system.

Background technique

A multi-input multi-output antenna system (Multi-input Multi-output, MIMO) is a model used to describe a multi-antenna wireless communication system. The transmitter uses multiple transmit antennas to send signals, and the receiver uses multiple receive antennas to receive and restore information.

Since the MIMO antenna system can increase the amount of data transmission without increasing the transmission power or bandwidth, the MIMO antenna system has been widely used in various communication devices.

At the receiving end of the MIMO antenna system, signal detection and search must be performed to restore the original information. However, as communication technology moves towards more complex B5G (Beyond 5G) and other next-generation satellite broadband communication backbone architectures, the complexity of signal detection and search grows exponentially with the modulation dimension, and signal detection and search become quite time-consuming. Researchers are working to come up with a new method of signal detection and search that could speed up the search while maintaining its accuracy.

Contents of the invention

The invention relates to a MIMO signal detection and search method, a decoding circuit and a receiving antenna system.

According to one aspect of the present invention, a signal detection and search method for a multi-input multi-output antenna system (Multi-Input Multi-Output, MIMO) is proposed. The signal detection and search method includes the following steps. A signal search tree is obtained, and multiple candidate signals are sorted at each level of the signal search tree. At each level of the signal search tree, candidate signals are scanned sequentially. In each level of the signal search tree, if a cumulative geometric distance is greater than or equal to a threshold, the unscanned candidate signals are excluded. If the cumulative geometric distance is less than the threshold, then update the threshold with the cumulative geometric distance. When all candidate signals are calculated, an estimated signal combination is output and the scanning of the signal search tree is ended.

In one embodiment, the signal detection and search method of the MIMO antenna system, wherein the candidate signals are sorted according to a plurality of geometric distances between the candidate signals and an estimated signal.

In one embodiment, the signal detection and search method of the MIMO antenna system, wherein the candidate signals are sorted from low to high according to the geometric distances.

In one embodiment, the signal detection and search method of the MIMO antenna system, wherein the candidate signals adopt an amplitude phase modulation system.

In one embodiment, the signal detection and search method of the MIMO antenna system, wherein the candidate signals adopt a quadrature amplitude modulation system.

In one embodiment, the signal detection and search method for the MIMO antenna system, wherein the candidate signals are searched using a depth-first search algorithm.

In one embodiment, the signal detection and search method of the MIMO antenna system, wherein a leftmost path of the signal search tree forms an initial solution.

According to another aspect of the present invention, a decoding circuit is provided. The decoding circuit includes a sorting unit, a control unit, a distance calculation unit and a threshold updating unit. The sorting unit is used for sorting multiple candidate signals at each level of a signal search tree. The control unit is used for sequentially scanning candidate signals at each level of the signal search tree. The distance calculation unit is used for calculating a cumulative geometric distance. In each level of the signal search tree, if the cumulative geometric distance is greater than or equal to a threshold, the control unit excludes unscanned candidate signals. If the cumulative geometric distance is smaller than the threshold, the threshold updating unit updates the threshold with the cumulative geometric distance. When all candidate signals are calculated, the control unit outputs an estimated signal combination and ends the scan of the signal search tree.

In one embodiment, the decoding circuit further includes an estimating unit for estimating an estimated signal according to a received signal, and the sorting unit is based on a plurality of geometries between the candidate signals and the estimated signal distance, sort the candidate signals.

In one embodiment, the decoding circuit, wherein the candidate signals are sorted according to the geometric distances from low to high.

In one embodiment, the decoding circuit, wherein the candidate signals adopt an amplitude phase modulation system.

In one embodiment, the decoding circuit, wherein the candidate signals adopt a quadrature amplitude modulation system.

In one embodiment, the decoding circuit, wherein the control unit uses a depth-first search algorithm to search the candidate signals.

In one embodiment, in the decoding circuit, a leftmost path of the signal search tree forms an initial solution.

According to a further aspect of the present invention, a receiving antenna system is proposed. The receiving antenna system includes a plurality of receiving antennas, an RF combining circuit, a plurality of RF chains, a plurality of analog-to-digital circuits and a baseband combining circuit. The radio frequency link is connected to the radio frequency combining circuit. The analog-to-digital circuits are respectively connected to the radio frequency link. The base frequency combining circuit is connected to the analog-to-digital conversion circuit. The fundamental frequency combining circuit includes a decoding circuit. The decoding circuit includes a sorting unit, a control unit, a distance calculation unit and a threshold updating unit. The sorting unit is used for sorting multiple candidate signals at each level of a signal search tree. The control unit is used for sequentially scanning candidate signals at each level of the signal search tree. The distance calculation unit is used for calculating a cumulative geometric distance. In each level of the signal search tree, if the cumulative geometric distance is greater than or equal to a threshold, the control unit excludes unscanned candidate signals. If the cumulative geometric distance is smaller than the threshold, the threshold updating unit updates the threshold with the cumulative geometric distance. After all the candidate signals are calculated, the control unit outputs an estimated signal combination and ends the scanning of the signal search tree.

In one embodiment, the receiving antenna system, wherein the decoding circuit further includes:

An estimation unit is used for estimating an estimated signal according to a received signal, and the sorting unit sorts the candidate signals according to a plurality of geometric distances between the candidate signals and the estimated signal.

In one embodiment, the receiving antenna system, wherein the candidate signals are sorted according to the geometric distances from low to high.

In one embodiment, the receiving antenna system, wherein the candidate signals adopt an amplitude phase modulation system.

In one embodiment, the receiving antenna system, wherein the candidate signals adopt a quadrature amplitude modulation system.

In one embodiment, the receiving antenna system, wherein the control unit uses a depth-first search algorithm to search for the candidate signals.

In one embodiment, the receiving antenna system, wherein a leftmost path of the signal search tree forms an initial solution.

In order to have a better understanding of the above-mentioned and other aspects of the present invention, the following specific examples are given in detail with the accompanying drawings as follows:

Description of drawings

FIG. 1 shows a transmitting antenna system and a receiving antenna system according to an embodiment of the present invention.

FIG. 2 is a program of signal detection and search according to an embodiment of the present invention.

FIG. 3A is a schematic diagram of 16-APSK encoding according to an embodiment of the present invention.

FIG. 3B is a schematic diagram of 32-APSK encoding according to an embodiment of the present invention.

FIG. 3C is a schematic diagram of 32-APSK encoding of unequal signal radii according to an embodiment of the present invention.

Fig. 4 is a signal search tree of the present invention.

FIG. 5 is a schematic diagram of a signal detection and search method for a multiple-input multiple-output antenna system (MIMO) according to an embodiment of the present invention.

Fig. 6 is a sorted signal search tree according to an embodiment of the present invention.

FIG. 7A shows the relationship between candidate signals and an estimated signal according to the present invention.

FIG. 7B shows the relationship between the candidate signal of the present invention and another estimated signal.

FIG. 7C shows the relationship between the candidate signal of the present invention and another estimated signal.

FIG. 7D shows the relationship between the candidate signal of the present invention and another estimated signal.

FIG. 8 is a block diagram of a decoding circuit according to an embodiment of the present invention.

9A to 9F are diagrams comparing the number of searches for signal detection and searching for 4 transmitting antennas and 4 receiving antennas according to the present invention using the present embodiment and the maximum likelihood estimation method.

FIGS. 10A-10F are comparison diagrams of bit error rates for signal detection and search of four transmitting antennas and four receiving antennas of the present invention using the present embodiment and the maximum likelihood estimation method.

[Description of Reference Signs]

100: Receiving Antenna System

110: RF combination circuit

120: RF link

130: Analog to digital circuit

140: Fundamental frequency combination circuit

141: decoding circuit

1411: sorting unit

1412: Estimation unit

1413: Control unit

1414: distance calculation unit

1415: Threshold update unit

900: Transmit Antenna System

910: Fundamental frequency precoding circuit

920: Digital to analog circuit

930: RF link

940: RF precoding circuit

C11, C12, C13, C14, C15, C16, C21, C22, C23, C24, C25, C26: search times curve

B11, B12, B13, B14, B15, B16, B21, B22, B23, B24, B25, B26: Bit error rate curves

N1, N2, N3, N4, N5, N6: nodes

P1: Get Program

P2: Decomposition procedure

P3: Search program

P4: Hard calculation program

P5: Iterative procedure

P6: Soft calculation program

PED: cumulative geometric distance

RA: receiving antenna

S110, S120, S130, S140, S150, S160, S170: steps

SC: Threshold

SS0, SS1, SS2, SS3: Candidate signals

TA: transmit antenna

TR0, TR1: Signal Search Tree

l ₀₀ , l ₀₁ , l ₀₂ , l ₀₃ , l ₁₀ , l ₁₁ , l ₁₂ , l ₁₃ , l ₂₀ , l ₂₁ , l ₂₂ , l ₂₃ , l ₃₀ , l ₃₁ , l ₃₂ , l ₃₃ : Geometric distance

估测信号

estimated signal

Detailed ways

Please refer to FIG. 1 , which shows a transmitting antenna system 900 and a receiving antenna system 100 according to an embodiment of the present invention. The transmit antenna system 900 includes a baseband pre-coding circuit (baseband pre-coding circuit) 910, multiple digital-to-analog circuits 920, multiple radio frequency links (RF chain) 930, a radio frequency pre-coding circuit (RF pre-coding circuit) ) 940 and a plurality of transmit antennas TA. The digital-to-analog circuit 920 is connected to the baseband precoding circuit 910 . The radio frequency links 930 are respectively connected to the digital-to-analog circuits 920 . The RF precoding circuit 940 is connected to the RF link 930 . The transmit antenna TA is connected to the RF precoding circuit 940 .

The wireless signal is transmitted to the receiving antenna system 100 after being transmitted through the transmitting antenna TA of the transmitting antenna system 900 . The receiving antenna system 100 includes a plurality of receiving antennas RA, a radio frequency combining circuit (RF combining circuit) 110, a plurality of radio frequency links (RF chain) 120, a plurality of analog-to-digital circuits 130 and a baseband combining circuit (basebandcombining circuit) 140. The RF combining circuit 110 is connected to the receiving antenna RA. The RF link 120 is connected to the RF combining circuit 110 . The analog-to-digital circuits 130 are respectively connected to the radio frequency link 120 . The baseband combining circuit 140 is connected to the analog-to-digital conversion circuit 130 .

The baseband combining circuit 140 includes a decoding circuit 141 . The decoding circuit 141 is used for analyzing the received signal to resolve the transmission signal sent by the transmission antenna system 900 .

Please refer to FIG. 2 , which is a signal detection and search procedure of an embodiment of the present invention. First, in the acquisition procedure P1, the received signal is acquired and channel estimation is performed.

Next, in the decomposition procedure P2, QR decomposition is performed on the channels.

Then, in the search program P3, signal detection and search are performed using the Maximum Likelihood (ML) method.

Then, it is applied in hard-decision program (Hard-decision) P4 or soft-type calculation program (Soft-decision) P6.

During the search procedure P3, the iterative procedure P5 can be used to improve the accuracy of the soft calculation procedure P6.

In this embodiment, the search speed of the search program P3 is improved through a new search strategy without compromising the accuracy of the hard calculation program P4 and the soft calculation program P6.

The signal detection and search method disclosed in this embodiment is applicable to the encoding of the amplitude phase modulation system (Amplitude and phase-shift keying modulation, APSK modulation), and is also applicable to the encoding of the quadrature amplitude modulation system (QAM, Quadrature Amplitude Modulation) .

Please refer to Figures 3A-3C, Figure 3A is a schematic diagram of 16-APSK encoding according to an embodiment of the present invention, Figure 3B is a schematic diagram of 32-APSK encoding according to an embodiment of the present invention, Figure 3C is a schematic diagram of an embodiment of the present invention Schematic diagram of 32-APSK encoding with equal signal radius. The next-generation satellite broadband communication backbone architecture such as B5G (Beyond 5G) has widely adopted the amplitude phase modulation system (APSK modulation). Each point on FIGS. 3A-3C is a candidate signal to be searched. As shown in FIGS. 3A-3C , the modulation dimension of the amplitude phase modulation system grows geometrically and the signal radius is not fixed, so the search complexity becomes quite high.

Taking M _T transmitting antennas TA and M _R receiving antennas RA as an example, the relationship between the received signal and the transmitted signal is as follows (1), where H is the channel response, s is the transmitted signal vector, y is the received data vector, and n is Noise vector.

Y＝Hs+n................................................ ............(1)

In the above search program P3, it is mainly required to solve the following formula (2):

其中R为上三角矩阵。After H is decomposed by the QR of the following formula (3), the following formula (4) can be obtained

where R is an upper triangular matrix.

可以替换为下式(5)。of formula (2)

It can be replaced by the following formula (5).

例如是下式(6)。Taking 4 transmit antennas TA and 4 receive antennas RA as an example, each receive antenna RA corresponds to 4 candidate signals SS0 , SS1 , SS2 , SS3 .

For example, it is the following formula (6).

Please refer to FIG. 4 , which is a signal search tree TR0 of the present invention. Taking 4 transmit antennas TA and 4 receive antennas RA as an example, the signal search tree TR0 has layers 0-3. The topmost layer ₃ represents 4 candidate signals SS0, SS1, SS2, SS3 of s3. Layer ₂ represents 4 candidate signals SS0, SS1, SS2, SS3 of s2. The _first layer represents 4 candidate signals SS0, SS1, SS2, SS3 of s1. Layer ₀ represents 4 candidate signals SS0, SS1, SS2, SS3 of s0. Any path from layer 3 to layer 0 constitutes a set of solutions of s ₃ , s ₂ , s ₁ , and s ₀ .

However, if the signal detection and search are performed in an exhaustive manner, a large amount of computing resources will be consumed and the computing speed will be delayed.

Please refer to FIG. 5 , which is a schematic diagram of a signal detection and search method for a multiple-input multiple-output antenna system (MIMO) according to an embodiment of the present invention. For the convenience of description, 4 transmit antennas TA and 4 receive antennas RA are taken as an example for illustration below. However, the technique of this embodiment is applicable to N transmit antennas TA and M receive antennas RA, where N and M are any positive integers greater than or equal to 2. First, in step S110, a signal search tree TR1 is obtained and a plurality of candidate signals SS0-SS3 are sorted at each level of the signal search tree TR0. Please refer to FIG. 6 , which is a sorted signal search tree TR1 according to an embodiment of the present invention. The arrangement order of the candidate signals SS0 to SS3 in each layer is not completely the same.

之间的关系。如图7A所示，候选信号SS0～SS3与估测信号/>

之间具有数个几何距离l₃₀～l₃₃。如6图6的第3层所示，候选信号SS1、SS3、SS0、SS2按照几何距离l₃₁、l₃₃、l₃₀、l₃₂由低至高排序。Please refer to FIG. 7A, which shows candidate signals SS0-SS3 and estimated signals of the present invention

The relationship between. As shown in FIG. 7A, the candidate signals SS0-SS3 and the estimated signal/>

There are several geometric distances l ₃₀ -l ₃₃ between them. As shown in the third layer of FIG. 6 , the candidate signals SS1 , SS3 , SS0 , and SS2 are sorted according to the geometric distances l ₃₁ , l ₃₃ , l ₃₀ , and l ₃₂ from low to high.

之间的关系。如图7B所示，候选信号SS0～SS3与估测信号/>

之间具有多个几何距离l₂₀～l₂₃。如图6的第2层所示，候选信号SS1、SS0、SS3、SS2按照几何距离l₂₁、l₂₀、l₂₃、l₂₂由低至高排序。Please refer to FIG. 7B, the candidate signals SS0-SS3 and estimated signals of the present invention

The relationship between. As shown in FIG. 7B, the candidate signals SS0-SS3 and the estimated signal/>

There are several geometric distances l ₂₀ -l ₂₃ between them. As shown in the second layer of FIG. 6 , the candidate signals SS1 , SS0 , SS3 , and SS2 are sorted according to the geometric distances l ₂₁ , l ₂₀ , l ₂₃ , and l ₂₂ from low to high.

之间的关系。如图7C所示，候选信号SS0～SS3与估测信号/>

之间具有多个几何距离l₁₀～l₁₃。如图6的第1层所示，候选信号SS0、SS2、SS1、SS3按照几何距离l₁₀、l₁₂、l₁₁、l₁₃由低至高排序。Please refer to FIG. 7C, which shows the candidate signals SS0-SS3 and estimated signals of the present invention

The relationship between. As shown in Figure 7C, the candidate signals SS0-SS3 and the estimated signal/>

There are several geometric distances l ₁₀ -l ₁₃ between them. As shown in the first layer of FIG. 6 , the candidate signals SS0 , SS2 , SS1 , and SS3 are sorted according to the geometric distances l ₁₀ , l ₁₂ , l ₁₁ , and l ₁₃ from low to high.

之间的关系。如图7D所示，候选信号SS0～SS3与估测信号/>

之间具有多个几何距离l₀₀～l₀₃。如图6的第0层所示，候选信号SS3、SS2、SS1、SS0按照几何距离l₀₃、l₀₂、l₀₁、l₀₀由低至高排序。Please refer to FIG. 7D, which shows the candidate signals SS0-SS3 and estimated signals of the present invention

The relationship between. As shown in Figure 7D, the candidate signals SS0-SS3 and the estimated signal/>

There are multiple geometric distances l ₀₀ -l ₀₃ between them. As shown in the 0th layer of FIG. 6 , the candidate signals SS3 , SS2 , SS1 , and SS0 are sorted according to the geometric distances l ₀₃ , l ₀₂ , l ₀₁ , and l ₀₀ from low to high.

After sorting in the above manner, a signal search tree TR1 as shown in FIG. 6 can be obtained. From layer 3 to layer 0 of the signal search tree TR1, the leftmost path of the signal search tree TR1 constitutes an initial solution.

Next, in step S120, the candidate signals SS0-SS3 are sequentially scanned in each layer of the signal search tree TR1. For example, in this embodiment, a depth-first-search algorithm (Depth-First-Search, DFS) is used to search the candidate signals SS0 - SS3 . After the initial solution (the leftmost path of the signal search tree TR1 ) is obtained, the search can be performed from the bottom layer (that is, layer 0). When searching on layer 0, the search is performed in the order of candidate signals SS3, SS2, SS1, and SS0. When searching on the first layer, the search is performed in the order of candidate signals SS0, SS2, SS1, and SS3. When searching on the second layer, the search is performed in the order of candidate signals SS1, SS0, SS3, and SS2. When searching on the third layer, the search is performed in the order of candidate signals SS1, SS3, SS0, and SS2.

In step S130, it is judged whether all candidate signals SS0, SS2, SS1, SS3 of each layer have been calculated. If all candidate signals SS0 , SS2 , SS1 , SS3 of each layer are calculated, proceed to step S140 ; if not all candidate signals SS0 , SS2 , SS1 , SS3 are calculated, proceed to step S150 .

In step S140, an estimated signal combination is output, and the scanning of the signal search tree TR1 is ended.

In step S150, during the scanning process of each layer of the signal search tree TR1, it is judged whether the cumulative geometric distance PED is greater than or equal to a threshold value SC. If the cumulative geometric distance PED is greater than or equal to the threshold value SC, go to step S160; if the cumulative geometric distance PED is smaller than the threshold value SC, go to step S170.

The initial value of the threshold value SC is infinite. After the initial solution is obtained, the threshold SC is updated to the cumulative geometric distance PED of the initial solution. Taking Figure 6 as an example, the cumulative geometric distance PED of the initial solution is the sum of the geometric distances l ₃₁ , l ₂₁ , l ₁₀ , and l ₀₃ .

In step S160, during the scanning process of each layer of the signal search tree TR1, the unscanned candidate signals SS0-SS3 are excluded.

In step S170, the threshold value SC is updated with the cumulative geometric distance PED.

Taking Figure 6 as an example, node N1 is the initial solution. The current threshold SC is the cumulative geometric distance PED of the node N1. After the node N1 is searched, it can be found that the cumulative geometric distance PED of the node N2 is greater than the threshold value SC, so the candidate signals SS2, SS1, and SS0 that have not been scanned in the sibling nodes are excluded.

After the node N3 is searched, it can be found that the cumulative geometric distance PED of the node N4 is greater than the threshold value SC, so the candidate signals SS2, SS1, and SS3 that have not been scanned in the sibling nodes are excluded.

After the node N5 is searched, it can be found that the cumulative geometric distance PED of the node N6 is smaller than the threshold SC, so the threshold SC is updated with the cumulative geometric distance PED of the node N6, and the search is continued.

According to the above method, during the search process, many unscanned candidate signals in the sibling nodes are excluded, so a large amount of computing resources can be saved, and the search speed can be greatly increased. In addition, the cumulative geometric distance PED of the excluded candidate signals will not be lower than the threshold value SC, so the best solution will not be excluded without compromising the search accuracy.

Please refer to FIG. 8 , which is a block diagram of the decoding circuit 141 according to an embodiment of the present invention. The decoding circuit 141 includes a sorting unit 1411 , an estimation unit 1412 , a control unit 1413 , a distance calculation unit 1414 and a threshold updating unit 1415 .

如上所述，排序单元1411按照候选信号SS0～SS3与估测信号/>

的几何距离l₃₁、l₃₃、l₃₀、l₃₂，排序候选信号SS1、SS3、SS0、SS2。排序单元1411按照候选信号SS0～SS3与估测信号/>

的几何距离l₂₁、l₂₀、l₂₃、l₂₂，排序候选信号SS1、SS0、SS3、SS2。排序单元1411按照候选信号SS0～SS3与估测信号/>

的几何距离l₁₀、l₁₂、l₁₁、l₁₃，排序候选信号SS0、SS2、SS1、SS3。排序单元1411按照候选信号SS0～SS3与估测信号/>

的几何距离l₀₃、l₀₂、l₀₁、l₀₀，排序候选信号SS3、SS2、SS1、SS0。The sorting unit 1411 is used for sorting the candidate signals SS0 - SS3 at each level of the signal search tree TR1 . The estimation unit 1412 is used for estimating each estimation signal according to a received signal

As mentioned above, the sorting unit 1411 sorts the candidate signals SS0-SS3 and the estimated signal>

The geometric distances l ₃₁ , l ₃₃ , l ₃₀ , l ₃₂ , sorting candidate signals SS1, SS3, SS0, SS2. The sorting unit 1411 sorts the candidate signals SS0-SS3 and the estimated signal/>

The geometric distances l ₂₁ , l ₂₀ , l ₂₃ , l ₂₂ , sorting candidate signals SS1, SS0, SS3, SS2. The sorting unit 1411 sorts the candidate signals SS0-SS3 and the estimated signal/>

The geometric distances l ₁₀ , l ₁₂ , l ₁₁ , l ₁₃ are the sorting candidate signals SS0, SS2, SS1, SS3. The sorting unit 1411 sorts the candidate signals SS0-SS3 and the estimated signal/>

The geometric distance l ₀₃ , l ₀₂ , l ₀₁ , l ₀₀ , sorting candidate signals SS3, SS2, SS1, SS0.

The control unit 1413 is used for sequentially scanning the candidate signals SS0 - SS3 at each level of the signal search tree TR1 .

The distance calculation unit 1414 is used for calculating the cumulative geometric distance PED. In each layer of the signal search tree TR1, if the cumulative geometric distance PED is greater than or equal to the threshold value SC, the control unit 1413 excludes the candidate signals SS0-SS3 that have not been scanned in the sibling nodes.

If the accumulated geometric distance PED is smaller than the threshold SC, the threshold update unit 1415 updates the threshold SC with the accumulated geometric distance PED.

Please refer again to FIGS. 9A-9F , which are diagrams comparing the number of searches for signal detection and searching for 4 transmitting antennas TA and 4 receiving antennas RA according to this embodiment and the maximum likelihood estimation method of the present invention. From Figures 9A to 9F, when using 8-APSK to 256-APSK, the search times curves C11, C12, C13, C14, C15, and C16 of this embodiment are significantly lower than the search times curves C21 and C22 of the maximum likelihood estimation method , C23, C24, C25, C26. That is to say, the signal detection and search method of this embodiment greatly speeds up the search speed.

Please refer to FIGS. 10A-10F again, which are comparison diagrams of bit error rates of signal detection and search performed by four transmitting antennas TA and four receiving antennas RA of the present invention using this embodiment and the maximum likelihood estimation method. From Fig. 10A～10F, adopt 8-APSK to 256-APSK, the bit error rate curve B11, B12, B13, B14, B15, B16 of this embodiment are equal to the bit error rate curve of the maximum likelihood estimation method B21, B22, B23, B24, B25, B26. That is to say, the signal detection and search method of this embodiment does not damage the search accuracy.

According to the above-mentioned embodiment, during the search process of the decoding circuit 141 , many unscanned candidate signals in the sibling nodes are excluded, so a large amount of computing resources can be saved, and the search speed can be greatly accelerated. In addition, the cumulative geometric distance of the excluded candidate signals will not be lower than the threshold, so there will be no case where the best solution will be excluded without compromising the search accuracy.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc. should be included in the protection scope of the present invention, therefore, the protection scope of the present invention should be based on the claims.

Claims (21)

1. A signal detection and search method for a multiple-input multiple-output antenna system, comprising: obtaining a signal search tree, and sorting a plurality of candidate signals at each layer of the signal search tree; In each layer of the signal search tree, scanning the candidate signals in sequence; In each layer of the signal search tree, if the cumulative geometric distance is greater than or equal to the threshold, then exclude the unscanned candidate signals; If the cumulative geometric distance is smaller than the threshold, updating the threshold with the cumulative geometric distance; and When all the candidate signals are calculated, the estimated signal combination is output and the scanning of the signal search tree is ended. 2. The signal detection and search method for a MIMO antenna system according to claim 1, wherein the candidate signals are sorted according to a plurality of geometric distances between the candidate signals and the estimated signal. 3. The signal detection and search method for a MIMO antenna system according to claim 2, wherein the candidate signals are sorted from low to high according to the geometric distances. 4. The signal detection and search method of the MIMO antenna system according to claim 1, wherein the candidate signals adopt an amplitude phase modulation system. 5. The signal detection and search method of the MIMO antenna system according to claim 1, wherein the candidate signals adopt a quadrature amplitude modulation system. 6. The signal detection and search method for MIMO antenna system according to claim 1, wherein the candidate signals are searched using a depth-first search algorithm. 7. The signal detection and search method for MIMO antenna system according to claim 1, wherein the leftmost path of the signal search tree constitutes the initial solution. 8. A decoding circuit, comprising: a sorting unit, configured to sort multiple candidate signals at each level of the signal search tree; The control unit is used to scan the candidate signals sequentially at each layer of the signal search tree; a distance calculation unit, configured to calculate cumulative geometric distances, in each layer of the signal search tree, if the cumulative geometric distance is greater than or equal to a threshold value, the control unit excludes the unscanned candidate signals; and a threshold updating unit, if the cumulative geometric distance is less than the threshold, the threshold updating unit updates the threshold with the cumulative geometric distance, and when all the candidate signals are calculated, the control unit outputs the estimated signal combination , and end the scan of the signal search tree. 9. The decoding circuit according to claim 8, further comprising: The estimating unit is configured to estimate an estimated signal according to the received signal, and the sorting unit sorts the candidate signals according to a plurality of geometric distances between the candidate signals and the estimated signal. 10. The decoding circuit according to claim 9, wherein the candidate signals are sorted according to the geometric distances from low to high. 11. The decoding circuit according to claim 8, wherein the candidate signals adopt an amplitude phase modulation system. 12. The decoding circuit according to claim 8, wherein the candidate signals adopt a quadrature amplitude modulation system. 13. The decoding circuit according to claim 8, wherein the control unit uses a depth-first search algorithm to search for the candidate signals. 14. The decoding circuit according to claim 8, wherein the leftmost path of the signal search tree constitutes the initial solution. 15. A receiving antenna system comprising: Multiple receiving antennas; RF combination circuit; A plurality of radio frequency links are connected to the radio frequency combined circuit; A plurality of analog-to-digital circuits are respectively connected to the radio frequency links; and The base frequency combination circuit is connected to these analog-to-digital circuits, the base frequency combination circuit includes a decoding circuit, and the decoding circuit includes: a sorting unit, configured to sort multiple candidate signals at each level of the signal search tree; a control unit, configured to sequentially scan the candidate signals at each level of the signal search tree; a distance calculation unit, used to calculate the cumulative geometric distance, in each layer of the signal search tree, if the cumulative geometric distance is greater than or equal to a threshold value, the control unit excludes the unscanned candidate signals; and a threshold updating unit, if the cumulative geometric distance is less than the threshold, the threshold updating unit updates the threshold with the cumulative geometric distance, and when all the candidate signals are calculated, the control unit outputs the estimated signal combination , and end the scan of the signal search tree. 16. The receiving antenna system according to claim 15, wherein the decoding circuit further comprises: The estimating unit is configured to estimate an estimated signal according to the received signal, and the sorting unit sorts the candidate signals according to a plurality of geometric distances between the candidate signals and the estimated signal. 17. The receiving antenna system according to claim 15, wherein the candidate signals are sorted according to the geometric distances from low to high. 18. The receiving antenna system according to claim 15, wherein the candidate signals adopt an amplitude phase modulation system. 19. The receiving antenna system according to claim 15, wherein the candidate signals adopt a quadrature amplitude modulation system. 20. The receiving antenna system according to claim 15, wherein the control unit searches for the candidate signals using a depth-first search algorithm. 21. The receiving antenna system of claim 15, wherein the leftmost path of the signal search tree constitutes the initial solution.

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