KR20170125527A - Symbol detection method in generalized spatial modulation multiple input multiple output system and receiver using thereof - Google Patents

Abstract

The present invention relates to a symbol detection method. The symbol detection method in a generalized spatial modulation multiple-input multiple-output (MIMO) antenna system can comprise: forming a plurality of subtree groups including a plurality of active transmission antenna nodes; calculating transmission costs for each of the plurality of subtree groups; and detecting combinations of the active transmission antennas and transmission symbols based on the calculated transmission costs. The spatial modulation MIMO antenna system can accurately and quickly detect the transmission antennas and the transmission symbols while reducing the calculation complexity of the process of detecting the transmission antennas and the transmission symbols.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a symbol detection method and a receiver using the symbol detection method in a generalized space-

The present invention relates to a symbol detection method and a receiver using the same in a generalized spatial-modulation multi-antenna system.

(MIMO) technology is being introduced to achieve high data rate and wide communication distance in a communication system. [0004] MIMO (Multi-Antenna) technology is used to transmit data at high speed without increasing bandwidth or increasing transmit power. And is applied to various wireless communication systems.

Since detection of data symbols in multi-antenna wireless communication has a high computational complexity, lowering the computational complexity is the key to practical applications. Higher throughput is required for next generation communications, and computational complexity is increasing accordingly. The background technology of the present application is disclosed in Korean Patent Registration No. 10-1136184.

Meanwhile, the spatial modulation system is receiving the spotlight as a next generation wireless communication system because it can transmit low power with low complexity of a transmitting side while maintaining the advantages of a multi-antenna system (Spatial Multiplexing, SMx).

Recently, a generalized spatial modulation system has been proposed in which symbols are transmitted by activating two or more antennas among a plurality of antennas. Since a symbol is transmitted by activating two or more antennas among a plurality of antennas, it is required to find a combination of a plurality of transmission antennas that transmit symbols and detect a symbol transmitted from the corresponding transmission antenna.

However, in the conventional spatial modulation system, the computational complexity of the symbol detection process is high, and thus there is a problem in implementing the symbol detection process in hardware.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and it is an object of the present invention to provide a spatial modulation multi-antenna system capable of detecting transmission antennas and transmission symbols more quickly and accurately while reducing computational complexity of a detection process of transmission antennas and transmission symbols, And a receiver using the same.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a symbol detection method and a receiver using the symbol detection method in a space-modulated multi-antenna system which can reduce the complexity of the detection process, .

It is to be understood, however, that the technical scope of the embodiments of the present invention is not limited to the above-described technical problems, and other technical problems may exist.

As a technical means for achieving the above technical object, a symbol detection method in a Spatial Modulation Multiple-input multiple-output system according to an embodiment of the present invention includes: (a) (B) calculating a transmission cost for each of the plurality of subtree groups, and determining a combination of active transmission antennas based on the calculated transmission cost and And detecting transmission symbols.

In addition, the number of the plurality of subtree groups may be determined based on the number of active transmission antennas among all transmission antennas.

In addition, the transmission cost may include a Euclidean distance value based on an active transmission antenna index and a transmission symbol index included in each of the plurality of subtree groups.

The step (b) may further include the steps of: (b1) calculating a Euclidean distance value for a first subtree group which is one of the plurality of subtree groups; (b2) (B3) comparing Euclidian distance values of the first subtree group with Euclidean distance values of the second subtree group, and (b4) comparing the Euclidean distance values of the plurality of Detecting a transmission antenna combination and a transmission symbol of a subtree group having a minimum Euclidean distance value among the subtree groups, and the steps (b1) to (b3) may be performed at least once.

The step (b) may store the smallest Euclidean distance value among the Euclidean distance values for the plurality of subtree groups.

In addition, the number of transmission symbols and the number of bits of the transmission symbol may be determined based on a signal modulation scheme.

In addition, the signal modulation method may be a BPSK (Quadrature Phase Shift Keying), QPSK (Quadrature Phase Shift Keying), QAM (Quadrature Amplitude Modulation), PSK (Phase Shift Keying), ASK (Amplitude Shift Keying) Or the like.

The step of detecting the transmit antenna combination and the transmit symbol of the subtree group having the minimum Euclidean distance value may be performed based on Equation (1).

In addition, the step of detecting the transmit antenna combination and the transmit symbol of the subtree group having the minimum Euclidean distance value is performed based on Equation (2) by applying QR decomposition to Equation (1) for each subtree group .

A receiver for performing symbol detection in a spatial multiplexing multiple antenna system according to an embodiment of the present invention includes a group forming unit for forming a plurality of subtree groups including a plurality of active transmission antenna nodes, And a detector for calculating a transmission cost for each of the subtree groups and detecting combinations of active transmission antennas and transmission symbols based on the calculated transmission cost.

The group forming unit may determine the number of the plurality of subtree groups based on the number of active transmission antennas among all the transmission antennas.

In addition, the transmission cost may include a Euclidean distance value based on an active transmission antenna index and a transmission symbol index included in each of the plurality of subtree groups.

The detection unit may calculate a first Euclidean distance value for a first subtree group which is one of the plurality of subtree groups, and calculate a first Euclidean distance value for the second subtree group, which is another one of the plurality of subtree groups, 2 Euclidean distance value and compares a first Euclidean distance value of the first subtree group with a second Euclidean distance value of the second subtree group and determines whether the Euclidean distance value of the plurality of subtree groups is a minimum The first Euclidean distance value calculation, the second Euclidean distance value calculation, and the comparison may be performed at least one time.

The receiver for performing symbol detection in the spatial multiplexing multiple antenna system according to an embodiment of the present invention may further include a storage unit for storing the smallest Euclidean distance value among the Euclidean distance values for the plurality of subtree groups .

In addition, the detection unit can detect a transmission antenna combination and a transmission symbol of a subtree group having a minimum Euclidean distance value.

In addition, the detection unit may detect a transmission antenna combination and a transmission symbol of a subtree group having a minimum Euclidean distance value by applying QR decomposition to each subtree group.

The above-described task solution is merely exemplary and should not be construed as limiting the present disclosure. In addition to the exemplary embodiments described above, there may be additional embodiments in the drawings and the detailed description of the invention.

According to the above-mentioned problem solving means of the present invention, a plurality of subtree groups including a plurality of active transmission antenna nodes are formed, and the number of subtree groups is determined based on the number of active transmission antennas among all transmission antennas And detects the combination of the active transmission antennas and the transmission symbols based on the transmission cost calculated for each of the plurality of subtree groups, thereby reducing the computational complexity of the detection process of the transmission antenna and the transmission symbol, And the transmission symbol can be detected.

According to the above-mentioned problem solving means of the present invention, subtree groups of antenna nodes are formed in consideration of the number of active transmission antennas, an optimum solution is calculated for each transmission antenna combination, and an antenna combination having an optimal solution is selected Therefore, the complexity of the detection process can be reduced and the hardware implementation can be simplified.

By dividing the entire tree into a plurality of subtree groups, the tree structure can be simplified and the number of node trees can be reduced. Therefore, it is possible to reduce the number of tree searches and achieve an optimum error rate performance Can be achieved.

1 is a schematic block diagram of a spatial modulation multi-antenna system in accordance with one embodiment of the present application.
FIG. 2 is a diagram schematically illustrating a data modulation method and a transmission process in a spatial-modulation multiple antenna system.
3 is a schematic operation flowchart of a symbol detection method in a spatial-modulation multiple antenna system according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating a tree structure for explaining a symbol detection method in a spatial-modulation multiple antenna system according to an embodiment of the present invention.
5 is a diagram schematically illustrating the configuration of a detector that can be applied to a symbol detection method in a spatial modulation multi-antenna system according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It should be understood, however, that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, the same reference numbers are used throughout the specification to refer to the same or like parts.

Throughout this specification, when an element is referred to as being "connected" to another element, it is intended to be understood that it is not only "directly connected" but also "electrically connected" or "indirectly connected" "Is included.

It will be appreciated that throughout the specification it will be understood that when a member is located on another member "top", "top", "under", "bottom" But also the case where there is another member between the two members as well as the case where they are in contact with each other.

Throughout this specification, when an element is referred to as "including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise.

The present invention relates to a technique for finding a combination of transmission antennas that efficiently transmit symbols and detecting symbols transmitted from corresponding transmission antennas in a spatial multiplexing multi-antenna system for transmitting symbols by activating two or more transmission antennas among a plurality of transmission antennas will be.

1 is a schematic block diagram of a spatial-modulation multi-antenna communication system according to an embodiment of the present invention.

Referring to FIG. 1, a spatial-multiplexed multiple-input multiple-output (OFDM) system 10 according to an embodiment of the present invention may include a transmitter 110 and a receiver 120.

The transmitter 110 may include a coding unit 111, a modulator 112, and a plurality of transmission antennas 113. [

The encoding unit 111 receives the bitstream and can encode the input bitstream according to a predetermined encoding scheme. For example, the encoding unit 111 may receive a signal including a plurality of bit information and divide it into an antenna bit block (or a section) and a symbol (or signal) modulation bit block (or a section). This can be more easily understood with reference to FIG.

FIG. 2 is a diagram schematically illustrating a data modulation method and a transmission process in a spatial-modulation multiple antenna system, and shows a data modulation method in the transmitter 110. FIG. The GSM modulator shown in FIG. 2 may include an encoding unit 111 and a modulation unit 112.

일 수 있다. 또한, 선택된 송신 안테나를 통해 심볼이 전송되므로, 이하에서는 선택된 송신 안테나의 수 N_A를 활성 송신 안테나의 수라 할 수 있다.Referring to FIG. 2, for example, in a spatial modulation system using a modulation method of M-QAM (Quadrature Amplitude Modulation) in which the total number of transmit antennas is N _T , N _A transmit antennas are selected The symbol can be transmitted. In the present invention applicable to a generalized spatial modulation system (GSM), ₂ ? N _A <N _T. At this time, the number of bits transmitted at one time is

Lt; / RTI &gt; Also, since the symbol is transmitted through the selected transmission antenna, the number N _A of the selected transmission antennas may be referred to as the number of active transmission antennas.

비트는 안테나 조합을 나타내고,

비트는 심볼을 나타낸다. 따라서, 부호화부(111)는 다수의 비트 정보를 포함하는 비트 스트림 신호(비트열) 중에서,

값에 해당하는 비트를 안테나 조합을 나타내는 안테나 비트 블록으로 분리 또는 할당하고,

값에 해당하는 비트를 심볼을 나타내는 심볼 변조 비트 블록으로 분리 또는 할당할 수 있다. 이때, M은 심볼 변조의 성상도가 표현 가능한 가짓수를 의미할 수 있다. 또한, 부호화부(111)는 안테나 비트 블록을 활성 송신 안테나 조합 인덱스로 부호화하고, 심볼 변조 비트 블록을 심볼 변조 성상도로 부호화할 수 있다.The bit stream input to the GSM modulator may be formed of one bit stream in the modulator. At this time,

Bit represents an antenna combination,

The bit represents a symbol. Therefore, the encoding unit 111 selects, from among bitstream signals (bit streams) including a plurality of bit information,

Separates or allocates a bit corresponding to a value into an antenna bit block representing an antenna combination,

The bit corresponding to the value can be separated or allocated as a symbol modulation bit block representing the symbol. Here, M may mean the number of symbols for which the constellation of symbol modulation can be expressed. The encoding unit 111 may encode the antenna bit block into the active transmit antenna combination index and encode the symbol modulation bit block in the symbol modulation property.

)개 중 어느 하나에 매핑시킬 수 있다. 이때, 안테나 조합 수(N_C)는 활성 송신 안테나의 수(N_A개)를 고려한 조합 수를 의미할 수 있다. 예를 들어, 전체 송신 안테나의 개수(N_T)가 4개이고, 활성 송신 안테나의 개수(N_A)가 2개인 경우,

는 4개 중에서 순서를 고려하지 않고 서로 다른 2개가 선택될 수 있는 경우의 수인 6을 의미할 수 있다. 이때, 안테나 조합 수(N_C)는 비트 할당 효율을 고려하여

를 통해 4로 계산될 수 있다.The modulator 112 can receive a signal output from the encoder 111 and generate a modulation symbol based on a predetermined signal modulation scheme. More specifically, based on the antenna mapping table shown in FIG. 2, the modulator 112 converts the antenna bit block into an antenna combination N _C (

). &Lt; / RTI &gt; At this time, the number N _{C of} antenna combinations may mean the number of combinations considering the number (N _A ) of active transmission antennas. For example, if the total number N _T of transmission antennas is four and the number N _A of active transmission antennas is two,

Can mean 6, which is the number of cases in which two different can be selected without considering the order among the four. At this time, the number of antenna combinations (N _C ), considering the bit allocation efficiency

Lt; RTI ID = 0.0 &gt; 4 &lt; / RTI &gt;

On the other hand, the modulator 112 may map the symbol modulation bit block to a symbol corresponding to the number N _A of active antennas (N _A ) based on the symbol mapping table shown in FIG. The number of transmission symbols and the number of bits of transmission symbols may be determined based on the signal modulation scheme.

The modulator 112 modulates a modulation symbol using a modulation scheme such as Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (QAM), Phase Shift Keying (ASK), Amplitude Shift Keying ) And FSK (Frequency Shift Keying).

In addition, the modulator 112 can transmit the generated symbol to the selected one of the plurality of transmit antennas 113, that is, the active transmit antenna. In the spatial multiplexing multiple antenna system 10 according to an exemplary embodiment of the present invention, two or more transmission antennas of a plurality of transmission antennas 113 can be activated, and accordingly, the modulation unit 112 converts the generated symbols into an active transmission To each antenna. Each of the activated transmission antennas may transmit the symbol received from the modulation unit 112 to the receiver 120 through wireless communication.

The receiver 120 may include a plurality of reception antennas 121, a detection unit 123, a demodulation unit 125, and a decoding unit 126. At this time, the detecting unit 123 may include a group forming unit (not shown) and a storing unit (not shown).

The receiver 120 may receive symbols (or signals) transmitted through active transmission antennas N _A of the plurality of transmission antennas 113. At this time, the receiver 120 can know only the number of active transmission antennas through the received symbols, and can not know which of the plurality of transmission antennas 113 the symbols are transmitted through. Accordingly, when a symbol is transmitted from the transmitter 110 through two or more transmission antennas among the plurality of transmission antennas 113, the receiver 120 finds a combination of two or more transmission antennas transmitting the symbol, Lt; RTI ID = 0.0 &gt; a &lt; / RTI &gt; According to the receiver 120 that performs symbol detection in the spatial-modulation multi-antenna system 10 according to an embodiment of the present invention, transmission antennas and transmission symbols can be detected more quickly and accurately while reducing computational complexity. Here is a closer look.

The group forming unit (not shown) may form a plurality of subtree groups including a plurality of active transmission antenna nodes. The active transmit antenna node may be a node in a tree structure corresponding to an active transmit antenna. The group forming unit may include only a plurality of active transmission antenna nodes in each subtree group when forming a plurality of subtree groups. Each subtree group may include a node corresponding to an antenna capable of activating the number (N _A ) of active transmission antennas. The group forming unit may determine the number of the plurality of subtree groups based on the number of active transmission antennas in the total number of transmission antennas.

)에 기초하여, 4개의 서브트리 그룹을 형성할 수 있다.For example, when the total number (N _T ) of transmission antennas is 4 and the number N _A of active transmission antennas is 2, the group forming unit calculates the number of combinations

, It is possible to form four subtree groups.

In addition, each of the plurality of subtree groups formed through the group forming unit may include a plurality of leaf nodes. This can be more easily understood with reference to FIG. 4 to be described later.

The detection unit 123 calculates a transmission cost for each of the plurality of subtree groups generated in the group formation unit, and calculates a combination of the active transmission antennas and a transmission symbol transmitted from the active transmission antenna of the combination based on the calculated transmission cost Detection is possible. Here, the transmission cost may include an Euclidean Distances value based on the active transmission antenna index and the transmission symbol index included in each of the plurality of subtree groups. In other words, the detection unit 123 can calculate the transmission cost for each of the plurality of subtree groups by calculating the Euclidean distance between the active transmission antenna nodes included in each of the plurality of subtree groups.

According to an embodiment of the present invention, the detecting unit 123 calculates (i) a Euclidean distance value for a first subtree group which is one of a plurality of subtree groups, (ii) (Iii) comparing the Euclidean distance value of the first subtree group with the Euclidean distance value of the second subtree group, iv) comparing the Euclidean distance value of the first subtree group with the Euclidean distance value of the second subtree group, The transmission antenna combination and the transmission symbol of the subtree group having the minimum Euclidean distance value can be detected. At this time, the detection unit 123 may perform the calculation of the first Euclidean distance value, (ii) the calculation of the second Euclidean distance value, and (iii) the comparison of the first Euclidean distance value and the second Euclidean distance value at least once . A more detailed description thereof will be described later.

Meanwhile, the process of comparing the calculated Euclidean distance values with respect to each of the plurality of subtree groups may be performed a number of times minus one in the number of the plurality of subtree groups. For example, when the number of the plurality of subtree groups is 4, the calculation of the Euclidean distance value is performed for each of the plurality of subtree groups, so that it can be performed four times. And the process of comparing the Euclidean distance values can be performed three times. More specifically, the first comparison can be performed by comparing the Euclidian distance value of the first subtree group and the Euclidean distance value of the second subtree group among the plurality of subtree groups. Thereafter, the second comparison can be performed by comparing the Euclidian distance values of the third subtree group based on the first comparison result value. The third comparison can be performed by comparing the Euclidean distance values of the fourth subtree group based on the second comparison result value. Accordingly, the detecting unit 123 compares the Euclidean distance value by 3 times (4-1 = 3), which is the number obtained by subtracting 1 from the number of the plurality of subtree groups, so that the Euclidean distances Value comparison can be performed.

The detection unit 123 calculates the Euclidean distance value based on the active transmission antenna index included in each subtree group and the index of the transmission symbol transmitted through each active transmission antenna with respect to each of the plurality of subtree groups, By identifying the subtree group having the smallest Euclidean distance value among the subtree groups, combinations of active transmission antennas and transmission symbols can be detected.

The detecting unit 123 compares the Euclidean distance value of the first subtree group with the Euclidean distance value of the second subtree group and then stores the Euclidean distance value having a smaller value in a storage unit (not shown) to be described later . The detection unit 123 can sequentially calculate the Euclidean distance values for all of the plurality of subtree groups. The Euclidean distance value calculated every time the Euclidean distance value is calculated for the new subtree group is compared with the Euclidean distance value stored in the storage unit Can be compared. At this time, if the Euclidean distance value for the new subtree group is smaller than the Euclidean distance value stored in advance in the storage unit, the detecting unit 123 may update and store the Euclidean distance value having a smaller value in the storage unit. Then, when the Euclidean distance value comparison is performed for all of the plurality of subtree groups, the detecting unit 123 calculates the Euclidean distance value of the subtree group having the smallest Euclidean distance value based on the Euclidean distance value having the smallest value stored in the storage unit. The transmit antenna combination and the transmit symbol can be detected. This will be described in more detail with reference to FIG. 4, which will be described later.

When calculating the Euclidean distance values for a plurality of subtree groups, the detecting unit 123 may calculate the Euclidean distance value for each of a plurality of leaf nodes included in each subtree group. Here, the Euclidean distance value for the leaf node means the Euclidean distance value from the root node to the corresponding leaf node. Then, the detecting unit 123 can identify leaf nodes (leaf nodes having the smallest Euclidean distance from the root node to the leaf node) having the smallest Euclidean distance value among the plurality of leaf nodes in each of the plurality of subtree groups have. Then, the detecting unit 123 can detect the transmit antenna combination and the transmit symbol of the leaf node having the smallest Euclidean distance value among the leaf nodes having the smallest Euclidean distance value identified in each of the plurality of subtree groups. This will be described in more detail with reference to FIG. 4, which will be described later.

On the other hand, the detection unit 123 can detect the transmission antenna combination and the transmission symbol of the subtree group having the minimum Euclidean distance value based on the following equations (1) to (2).

) 중 활성 송신 안테나 수(N_A)의 열벡터의 조합으로 이루어진 서브 채널 행렬(N_R X N_A 행렬)을 나타낸다. s는 활성 송신 안테나에 의해 송신된 심볼 벡터를 나타낸다. 달리 말해, s는 송신 심볼 벡터 중 N_A개의 심볼만으로 이루어진 벡터(N_A X 1)를 나타낸다. i는 활성 송신 안테나 조합의 인덱스를 나타낸다.Here, y denotes a received symbol vector of N _R X 1. H _i is a wireless communication channel matrix (N _R x N _T matrix, N _R N) based on the number of receiving antennas (N _R ) and the number of transmitting antennas (N _T )

(N _R X N _A matrix) consisting of a combination of column vectors of the number of active transmission antennas (N _A ). s represents the symbol vector transmitted by the active transmit antenna. In other words, s represents a vector (N _A X 1) consisting of only N _A symbols of the transmission symbol vectors. i represents the index of the active transmit antenna combination.

According to Equation (1), the number of combinations in which the number of the plurality of subtree groups formed through the group forming unit can be selected as the active transmission antenna among all the transmission antennas, that is, the number of active transmission antennas is considered.

Next, the detection unit 123 applies Equation (1) to Equation (2) by applying QR decomposition to H _i in Equation (1) for each subtree group (for each antenna combination considering the number of active transmission antennas) You can convert them together. The detection unit 123 can detect the transmission antenna combination and the transmission symbol of the subtree group having the minimum Euclidean distance value based on Equation (2).

의 계산을 통해, i번째 서브트리 그룹(i번째 활성 송신 안테나의 조합)에서

부터 s_i의 순서로 해(유클리드 거리값, 송신 비용)를 계산할 수 있다. 달리 말해, 검출부(123)는 i번째 서브트리 그룹 내에서 계층 순으로 해를 계산할 수 있다. 검출부(123)는 수학식 2에 기초하여, 활성 송신 안테나의 조합 및 송신 심볼의 검파 방법을 도 4와 같이 트리(tree) 구조로 표현할 수 있으며, 후술하여 보다 자세히 설명하기로 한다.At this time, H _i = Q _i R _i , and R _i can have an upper triangular shape. Therefore, the detection unit 123

(The combination of the i &lt; th &gt; active transmission antennas)

(Euclidean distance value, transmission cost) can be calculated in the order of s ₁ to s _i . In other words, the detection unit 123 can calculate the solution in the order of the hierarchy in the ith subtree group. The detection unit 123 can express the combination of the active transmission antennas and the detection method of the transmission symbol on the basis of Equation (2) as a tree structure as shown in FIG. 4, and will be described later in more detail.

In other words, the detecting unit 123 generates a sub-channel matrix H _i corresponding to N _C active antenna combinations (or each subtree group) using the wireless communication channel matrix H through Equations 1 and 2 can do. Then, the detector 123 finds a symbol having a minimum transmission cost using the sub-channel matrix H _i and outputs a corresponding cost function. Then, the detector 123 compares the output N _C cost functions, and detects the active antenna combination and the transmission symbol based on the cost function having the minimum value among the cost functions.

The storage unit may store the smallest Euclidean distance value among the Euclidean distance values for the plurality of subtree groups. The storage unit may update and store the Euclidean distance value having a smaller value when the Euclidean distance value for the new subtree group is smaller than the Euclidean distance value stored in advance.

The storage unit is configured to associate with a plurality of NC subtree groups considering the number of active transmission antennas, and to activate the active nodes for each of the nodes (active transmission antenna nodes), leaf nodes, and subtree groups calculated by the detection unit 123 The Euclidean distance values of the transmit antenna index and the transmit symbol index pair.

The demodulation unit 125 demodulates a symbol (signal) detected by the detection unit 123 based on the active transmission antenna index and the transmission symbol index detected by the detection unit 123 by using the modulation applied by the modulation unit 112 of the transmitter 110 The demodulation method corresponding to the demodulation method, and the bit stream inputted to the transmitter 110 can be restored. Based on this, the number of transmission symbols detected by the detection unit 123 and the number of bits of the transmission symbol can be determined based on the signal modulation method. As described above, the signal modulation method can be classified into BPSK (Binary Phase Shift Keying) (Quadrature Phase Shift Keying), Quadrature Amplitude Modulation (QAM), Phase Shift Keying (PSK), Amplitude Shift Keying (ASK), and Frequency Shift Keying (FSK).

The decoding unit 126 decodes the bit stream demodulated by the demodulation unit 125 based on the decoding system corresponding to the encoding system applied by the encoding unit 111 of the transmitter 110 and finally reconstructs the transmission data have.

Hereinafter, the operation flow of the present invention will be briefly described based on the above description.

3 is a schematic operation flowchart of a symbol detection method in a spatial-modulation multiple antenna system according to an embodiment of the present invention.

The symbol detection method in the spatial multiplexing multiple antenna system shown in FIG. 3 can be performed by the spatial modulation multi-antenna system 10 described above. Therefore, although omitted in the following description, the description of the spatial multiplexing multi-antenna system 10 can be similarly applied to FIG.

Referring to FIG. 3, in step S310, a symbol detection method in a spatial modulation multi-antenna system according to an embodiment of the present invention includes a plurality of subtrees including a plurality of active transmission antenna nodes by a group formation unit (not shown) Group can be formed.

At this time, the number of the plurality of subtree groups formed in step S310 may be determined based on the number of active transmission antennas among all the transmission antennas. More specifically, the number of the plurality of subtree groups can be determined based on the number of cases in which the active transmission antennas can be selected without considering the order among all the transmission antennas.

Next, in step S320, the detection unit 123 can calculate the transmission cost for each of the plurality of subtree groups formed in step S310.

At this time, the transmission cost may include the Euclidean distance value based on the active transmission antenna index and the transmission symbol index included in each of the plurality of subtree groups.

In addition, in step S320, when the transmission cost is calculated, the detecting unit 123 may store the smallest Euclidean distance value among the Euclidean distance values for the plurality of subtree groups.

Also, in step S320, combinations of active transmission antennas and transmission symbols can be detected based on the calculated transmission cost.

At this time, in step S320, the detecting unit 123 calculates the first Euclidean distance value for the first subtree group, which is one of the plurality of subtree groups, and calculates the first Euclidean distance value for the second subtree group The first Euclidean distance value of the first subtree group is compared with the second Euclidean distance value of the second subtree group, and among the plurality of subtree groups, the Euclidean distance value of the sub- The transmission antenna combination and the transmission symbol of the tree group can be detected. At this time, the calculation of the first Euclidean distance value, the calculation of the second Euclidean distance value, and the comparison of the first Euclidean distance value and the second Euclidean distance value may be performed at least once.

In more detail, assume that a plurality of subtree groups are formed. In step S320, the detecting unit 123 may calculate the Euclidean distance value for the first subtree group among the plurality of subtree groups, and store the calculated Euclidean distance value for the first subtree group in a storage unit (not shown) have. Then, the detecting unit 123 may calculate the Euclidean distance value for the second subtree among the plurality of subtree groups. Then, the detector 123 may compare the Euclidean distance value for the first subtree group stored in advance in the storage unit with the Euclidean distance value for the second subtree group. As a result of the comparison, if the Euclidean distance value for the second subtree group is smaller than the Euclidean distance value for the first subtree group stored previously, the detecting unit 123 determines that the Euclidean distances for the second subtree group, The distance value can be updated and stored in the storage unit. Then, the detecting unit 123 may calculate the Euclidean distance value for the third subtree among the plurality of subtree groups. Then, the detecting unit 123 may compare the Euclidean distance value for the second subtree group stored in the storage unit with the Euclidean distance value for the third subtree group. As a result of comparison, if the Euclidean distance value for the third subtree group is larger than the Euclidean distance value for the previously stored second subtree group, the detecting unit 123 detects the Euclidean distances for the fourth subtree group among the plurality of subtree groups Euclidean distance values can be calculated. Then, the detecting unit 123 may compare the Euclidean distance value for the second subtree group stored in the storage unit with the Euclidean distance value for the fourth subtree group. As a result of the comparison, if the Euclidean distance value for the fourth subtree group is smaller than the Euclidean distance value for the second subtree group previously stored, the detecting unit 123 determines that the Euclidean distances for the fourth subtree The distance value can be updated and stored in the storage unit. Next, when the Euclidean distance value comparison is performed for all of the plurality of subtree groups (four subtree groups) formed, the detecting unit 123 calculates the fourth subtree having the smallest Euclidean distance value among the plurality of subtree groups, Based on the group, the transmission antenna combination and the transmission symbol of the fourth subtree group can be detected.

According to an embodiment of the present invention, calculating the Euclidean distance value for each of the plurality of subtree groups includes calculating the Euclidean distance value for each of the plurality of leaf nodes included in each subtree group To calculate the Euclidean distance value from each node to each leaf node). For reference, as described above, the Euclidean distance value for the leaf node means the Euclidean distance value from the root node to the corresponding leaf node.

That is, in step S320, the detecting unit 123 may calculate the Euclidean distance value for each of a plurality of leaf nodes included in each subtree group when calculating Euclidean distance values for a plurality of subtree groups. Thereafter, the detecting unit 123 can identify the leaf node having the smallest Euclidean distance value among the plurality of leaf nodes in each of the plurality of subtree groups. Then, the detecting unit 123 can detect the transmission antenna combination and the transmission symbol of the leaf node having the smallest Euclidean distance value among the leaf nodes, which are the smallest Euclidean distance values identified in each of the plurality of subtree groups .

For example, assume that a first subtree group among a plurality of subtree groups includes a first leaf node to a fourth leaf node as a plurality of leaf nodes.

The detection unit 123 may sequentially calculate the Euclidean distance values for each of the plurality of leaf nodes included in the first subtree group. The detecting unit 123 may calculate the Euclidean distance value for the first leaf node by calculating the Euclidean distance value from the root node to the first leaf node. In addition, the detection unit 123 may store the Euclidean distance value for the first leaf node in the storage unit. Then, the detecting unit 123 can calculate the Euclidean distance value for the second leaf node by calculating the Euclidean distance value from the root node to the second leaf node. The detecting unit 123 may then compare the Euclidean distance value for the first leaf node stored in advance in the storage unit with the Euclidean distance value for the second leaf node. As a result of the comparison, if the Euclidean distance value for the second leaf node is smaller than the Euclidean distance value for the first stored leaf node, the detecting unit 123 calculates the Euclidean distance value for the second leaf node having a small Euclidean distance value Can be updated and stored in the storage unit.

Then, the detection unit 123 may calculate the Euclidean distance value for each of the third leaf node and the fourth leaf node included in the first subtree group as well as the first leaf node and the second leaf node. At this time, The detection unit 123 can compare the Euclidean distance value previously stored in the storage unit with the Euclidean distance value for each leaf node. As a result of comparison, the detection unit 123 can store a value having the smallest Euclidean distance value in the storage unit. When the calculation and comparison of the Euclidean distance values are completed for each of the first to fourth leaf nodes included in the first subtree group, the detecting unit 123 detects the leaf node having the minimum Euclidean distance value in the first subtree group, Can be identified. For example, in the first subtree group, it is assumed that a fourth leaf node is a leaf node having a minimum Euclidean distance value.

The detection unit 123 may calculate the Euclidean distance value for each of the plurality of leaf nodes included in the second subtree group. At this time, the Euclidean distance value calculation, comparison, and value storing method for each leaf node can be applied in the same manner as the above-described logic, and thus the following description will be omitted.

When the Euclidean distance value is calculated and compared with respect to each of the first to fourth leaf nodes included in the two subtree groups, the detecting unit 123 calculates the leaf node having the minimum Euclidean distance value in the second subtree group Can be identified. For example, assume that the first leaf node in the second subtree group is a leaf node having a minimum Euclidean distance value. Also, with this logic, it is assumed that the second leaf node has the minimum Euclidean distance value in the third subtree group, and the first leaf node has the minimum Euclidean distance value in the fourth subtree group.

Thereafter, the detection unit 123 detects the leaf nodes having the minimum Euclidean distance value identified in each subtree group (i.e., the fourth leaf node in the first subtree group, the first leaf node in the second subtree group, The leaf node having the smallest value can be identified based on the first leaf node in the first subtree group, the second leaf node in the third subtree group, and the first leaf node in the fourth subtree group. For example, when the second leaf node in the third subtree group has the smallest Euclidean distance value, the detecting unit 123 detects the transmission antenna combination and the transmission symbol corresponding to the second leaf node in the third subtree group .

On the other hand, in step S320, the detecting unit 123 can detect the transmission antenna combination and the transmission symbol of the subtree group having the minimum Euclidean distance value based on Equations (1) and (2) It will be omitted.

In the above description, steps S310 to S320 may be further divided into additional steps or combined into fewer steps, according to an embodiment of the present invention. Also, some of the steps may be omitted as necessary, and the order between the steps may be changed.

As described above, according to an embodiment of the present invention, unlike the conventional scheme in which a tree structure is formed by considering all transmission antennas and the Euclidean distance is calculated for each leaf node, a node corresponding to an active antenna The number of node trees is reduced, and the complexity of calculation of the detection process can be reduced accordingly.

FIG. 4 is a diagram illustrating a tree structure for explaining a symbol detection method in a spatial-modulation multiple antenna system according to an embodiment of the present invention.

Referring to FIG. 4, for example, in a spatial multiplexing multiple antenna system according to an exemplary embodiment of the present invention, the total number N _T of transmission antennas is 4, the total number N _R of reception antennas is 4, Suppose that the number of antennas (N _A ) is 2, and the constellation of symbol modulation is expressed by the number of possible representations (M). The calculation of Equation (2) may be expressed as Equation (3) below. Equation (3) represents the Euclidean distance value of each leaf node.

는 송신 심볼에 영향을 받지 않고,

에 의해서만 영향을 받음을 알 수 있다. 이에 따라, 검출부(123)를 통해 계산되는

는 안테나 전체 송신 안테나 중에서 선택되는 송신 안테나(활성 송신 안테나)의 조합마다 값이 다르게 산출될 수 있으며, 이는 트리 구조 내의 루트(Root)에서 계층 1(layer 1)의 노드(활성 송신 안테나 노드) 정점(vertex)까지의 엣지 가중치(edge weight)로 표현될 수 있다. According to Equation (3)

Is not affected by the transmission symbol,

And that the effect of the Accordingly, the calculation is performed through the detection unit 123

(Active Transmission Antenna Node) at the root in the tree structure (active transmission antenna node) at the root in the tree structure, can be expressed by an edge weight up to a vertex.

)가 4이므로, 그룹 형성부는 전체 트리 구조(300)를 4개의 서브트리 그룹(310, 320, 330, 340)으로 형성할 수 있다. 이때, 제1 서브트리 그룹(310)은 4개의 송신 안테나 중 1 송신 안테나와 2 송신 안테나가 활성화된 경우를 고려하여 형성된 그룹으로서, 제1 활성 송신 안테나 노드와 제2 활성 송신 안테나 노드를 포함할 수 있다.In one embodiment of FIG. 4, the number of combinations N _C (

) Is 4, the group forming unit can form the entire tree structure 300 as four subtree groups 310, 320, 330, and 340. In this case, the first subtree 310 includes a first active transmission antenna node and a second active transmission antenna node, which are formed in consideration of the case where one transmission antenna and two transmission antennas are activated among four transmission antennas .

Likewise, the second subtree 320 may be a group formed considering the case where one transmission antenna and three transmission antennas are activated among the four transmission antennas. The third subtree 330 may be a group formed considering the case where one transmit antenna and four transmit antennas are activated among the four transmit antennas. The fourth subtree group 340 may be a group formed considering two transmit antennas and three transmit antennas among the four transmit antennas. One of the four subtree groups 310, 320, 330, and 340 may include two transmit antennas and four transmit antennas. In this case, Or a combination of three transmit antennas and four transmit antennas.

The values shown in Equation (3) represent values corresponding to the first subtree group 310, and for each of the second subtree group 320 to the fourth subtree group 340, combinations of active transmission antennas A value such as Equation (3) can be calculated based on H _i every time.

After the plurality of subtree groups 310, 320, 330, and 340 are formed through the group forming unit, the detecting unit 123 finds the optimal symbol in each subtree group, Active antenna combinations and transmit symbols can be obtained. In other words, the detecting unit 123 can calculate the Euclidean distance value for each subtree group, and can identify the subtree group having the minimum transmission cost based thereon. The detection unit 123 may then detect the transmission antenna combination and the transmission symbol of the subtree group having the identified minimum transmission cost.

At this time, the detecting unit 123 can calculate the Euclidean distance value for each of the plurality of subtree groups 310, 320, 330, and 340. In particular, for each of the plurality of leaf nodes included in the subtree group, Can be calculated. Here is a closer look.

Referring to FIG. 4, the first subtree 310 may include a plurality of nodes 31, 32, 33, 34, 35, 36, 37. Here, the fourth node 34 is the first leaf node 311, the fifth node 35 is the second leaf node 312, the sixth node 36 is the third leaf node 313, And the seventh node 37 may be the fourth leaf node 314. [

The detection unit 123 can calculate the Euclidean distance value for the first leaf node 311 by calculating the Euclidean distance value from the root node to the fourth node 34. [ The detecting unit 123 can also calculate the Euclidean distance value for the second leaf node 312 by calculating the Euclidean distance value from the root node to the fifth node 35. [ The detecting unit 123 can calculate the Euclidean distance value for the third leaf node 313 by calculating the Euclidean distance value from the root node to the sixth node 36. [ The detection unit 123 can calculate the Euclidean distance value for the fourth leaf node 314 by calculating the Euclidean distance value from the root node to the seventh node 37. [

The detection unit 123 may calculate the Euclidean distance value sequentially using Equation (3) for each of the leaf nodes 311, 312, 313, and 314 included in the first subtree group 310 . At this time, the detecting unit 123 compares the calculated Euclidean distance values for each leaf node, and stores the Euclidean node value having the smallest value in the storage unit. Examples of calculating, comparing, and storing Euclidean distance values between leaf nodes have been described in detail in detail above, and therefore duplicate descriptions will be omitted.

When the Euclidean distance values are calculated and compared with respect to each of the first leaf node 311 to the fourth leaf node 314 included in the first subtree group 310, RTI ID = 0.0 &gt; 310, &lt; / RTI &gt; Thereafter, the detecting unit 123 also detects, for each of the second subtree group 320 to the fourth subtree group 34, a leaf node having the smallest Euclidean distance value among a plurality of leaf nodes included in each subtree group Can be identified.

If the leaf node having the minimum Euclidean distance value is identified for each of the plurality of subtree groups, the detecting unit 123 can identify the leaf node having the smallest Euclidean distance value among the identified leaf nodes. The detection unit 123 may then detect the active transmit antenna combination and transmit symbol corresponding to the identified leaf node based on the finally identified leaf node.

In the conventional symbol detection method, the tree structure to be expressed is irregular. On the other hand, in the symbol detection method in the spatial-modulation multiple antenna system according to an embodiment of the present invention, a tree structure can be formed simply and regularly as shown in FIG. Accordingly, the symbol detection method of the present invention is simple to implement in hardware. In addition, the symbol detection method of the present invention can have an optimal error rate performance while minimizing an unnecessary tree search because the number of vertices of a node in the tree structure is much smaller than that of the prior art.

Since the number of visited node vertices in the tree search means the number of times the Euclidean distance value is calculated, the symbol detection method according to an embodiment of the present invention can perform tree search with low complexity.

5 is a diagram schematically illustrating a configuration of a detector that can be applied to a symbol detection method in a spatial-modulation multiple antenna system according to an embodiment of the present invention.

Referring to FIG. 5, a symbol detection method in a spatial modulation multiple antenna system according to an embodiment of the present invention may perform symbol detection using one SMx detector as shown in FIG. 5 (a) ), The symbol detection may be performed using N _C SMx detectors.

When one detector is used as shown in FIG. 5 (a), the detector 123 according to an embodiment of the present invention performs detection on each subtree group to search for one antenna combination and its corresponding symbol It is possible to generate corresponding N _C sub-channel matrices H _i and perform N _{C number} of symbol detection. For example, assume that four subtree groups are formed as shown in FIG. 4, and the detection unit 123 performs detection using one detector. In this case, the detection unit 123 can perform four symbol detection with one detector.

Meanwhile, when N _C symbol detectors are formed in parallel in FIG. 5B, the N _C symbol detectors may generate the sub-channel matrix H _i and perform symbol detection once. More specifically, the first symbol detector may perform symbol detection on the first subtree group. And the second symbol detector may perform symbol detection on the second subtree group. The third symbol detector may perform symbol detection on the third subtree group. And the fourth symbol detector may perform symbol detection on the fourth subtree group. Accordingly, when a plurality of symbol detectors are used, each symbol detector can perform only one symbol detection.

The method of detecting a symbol in a spatial multiplexing multi-antenna system according to an exemplary embodiment of the present invention may be implemented in the form of a program command that can be performed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the medium may be those specially designed and configured for the present invention or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

It will be understood by those of ordinary skill in the art that the foregoing description of the embodiments is for illustrative purposes and that those skilled in the art can easily modify the invention without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

110: Transmitter 111:
112: Modulation section 113: Transmission antenna
120: receiver 123:
125: Demodulation unit 126: Decoding unit

Claims (17)

Spatial modulation In a symbol detection method in a multiple-input multiple-output (MIMO) system,
(a) forming a plurality of subtree groups including a plurality of active transmit antenna nodes;
(b) calculating a transmission cost for each of the plurality of subtree groups, detecting combinations of active transmission antennas and transmission symbols based on the calculated transmission cost,
/ RTI &gt; The method according to claim 1,
Wherein the number of the plurality of subtree groups is determined based on the number of active transmission antennas among the total transmission antennas. The method according to claim 1,
Wherein the transmission cost comprises a Euclidean distance value based on an active transmit antenna index and a transmit symbol index included in each of the plurality of subtree groups. The method of claim 3,
The step (b)
(b1) calculating an Euclidean distance value for a first subtree which is one of the plurality of subtree groups;
(b2) calculating a Euclidean distance value for a second subtree group which is another one of the plurality of subtree groups;
(b3) comparing Euclidean distance values of the first subtree group and Euclidean distance values of the second subtree group; And
(b4) detecting a transmission antenna combination and a transmission symbol of a subtree group having a minimum Euclidean distance value among the plurality of subtree groups,
Wherein the steps (b1) to (b3) are performed at least once. The method of claim 3,
The step (b)
And stores the smallest Euclidean distance value among the Euclidean distance values for the plurality of subtree groups. The method according to claim 1,
Wherein the number of transmission symbols and the number of bits of the transmission symbol are determined based on a signal modulation scheme. The method according to claim 6,
The signal modulation scheme may be at least one of Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (QAM), Phase Shift Keying (PSK), Amplitude Shift Keying (ASK) The signal detection method comprising the steps of: 5. The method of claim 4,
Wherein the step of detecting the transmit antenna combination and the transmit symbol of the subtree group with the minimum Euclidean distance value is performed based on Equation (1).
[Equation 1]

Here, y is a received symbol vector, H _i is a subchannel matrix formed by a combination of column vectors of the number of active transmission antennas among channel matrixes based on the number of receiving antennas and the number of transmitting antennas, s is a symbol vector transmitted by an active transmitting antenna, i is the index of the active transmit antenna combination. 9. The method of claim 8,
The step of detecting the transmit antenna combination and the transmit symbol of the subtree group having the minimum Euclidean distance value may be performed by applying QR decomposition to H _i of Equation 1 for each subtree group, Wherein the symbol detection method is performed.
&Quot; (2) &quot;

A receiver for performing symbol detection in a space-modulated multi-antenna system,
A group forming unit forming a plurality of subtree groups including a plurality of active transmission antenna nodes; And
A detector for calculating a transmission cost for each of the plurality of subtree groups and detecting combinations of active transmission antennas and transmission symbols based on the calculated transmission cost,
And a receiver. 11. The method of claim 10,
The group-
And determines the number of the plurality of subtree groups based on the number of active transmission antennas among the total transmission antennas. 11. The method of claim 10,
Wherein the transmission cost comprises a Euclidean distance value based on an active transmit antenna index and a transmit symbol index included in each of the plurality of subtree groups. 13. The method of claim 12,
Wherein:
A first Euclidean distance value for a first subtree group which is one of the plurality of subtree groups,
Calculating a second Euclidian distance value for a second subtree group that is another one of the plurality of subtree groups,
Compare the first Euclidean distance value of the first subtree group with the second Euclidean distance value of the second subtree group,
Detecting a transmission antenna combination and a transmission symbol of a subtree group having a minimum Euclidean distance value among the plurality of subtree groups,
Calculate the first Euclidian distance value, calculate the second Euclidian distance value, and perform the comparison at least once. 14. The method of claim 13,
A storage unit for storing the smallest Euclidean distance value among the Euclidean distance values for the plurality of subtree groups,
&Lt; / RTI &gt; 14. The method of claim 13,
Wherein the detecting unit detects a transmission antenna combination and a transmission symbol of a subtree group having a minimum Euclidean distance value based on Equation (3).
&Quot; (3) &quot;

Here, y is a received symbol vector, H _i is a subchannel matrix formed by a combination of column vectors of the number of active transmission antennas among channel matrixes based on the number of receiving antennas and the number of transmitting antennas, s is a symbol vector transmitted by an active transmitting antenna, i is the index of the active transmit antenna combination. 16. The method of claim 15,
The detection unit applies QR decomposition to the H _i of Equation (3) for each subtree group, detects the transmission antenna combination and the transmission symbol of the subtree group having the minimum Euclidean distance value based on Equation (4) Receiver.
&Quot; (4) &quot;

A computer-readable recording medium on which a program for executing the method of any one of claims 1 to 9 is recorded.

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