JP5822549B2 - Signal transmission method, signal transmission system and transmitter - Google Patents

Description

  The present invention relates to wireless communication technology, and more particularly to a signal transmission method, a signal transmission system, a transmitter, and a receiver.

  With the development of wireless communication technology, people have submitted higher demands on the effectiveness and reliability of wireless transmission. The multi-antenna technology is widely used because it can fully utilize multipath transmission in radio propagation and greatly improves the frequency utilization efficiency and link reliability.

  Considering that when a signal is transmitted to a radio channel, it is affected by the fading effect of the radio channel, it is possible to perform coded transmission and reception analysis of the signal using coherent transmission detection technology in the application of multi-antenna technology Many. The coherent transmission detection technology combines the diversity gain of multi-antenna and the coding gain of channel coding, and can effectively resist the fading effect of the radio channel without reducing the data transfer rate. High data transmission can be realized. However, coherent detection requires accurate channel estimation, and if there is a relatively large relative velocity between the sender and receiver, the coherent times are compared, for example, in a fast moving environment. Therefore, if the frequency of the pilot sequence for channel estimation is insufficient, the accuracy of channel estimation is greatly reduced, and the loss of system performance is further increased. On the other hand, when a large number of pilot sequences are used, the frequency utilization efficiency of the system is reduced, and it is useless to use a large number of pilot sequences in a low-speed moving environment, which increases the cost of channel estimation. Thus, for systems using coherent transmission detection, a high speed mobile environment is a challenge.

  Therefore, in the application of multi-antenna technology, non-coherent transmission detection technology also exists. Non-coherent detection does not require channel estimation and is not affected by high-speed moving environments. And since channel information is not required, extra pilot overhead is not required for non-coherent transmission detection. However, non-coherent transmission detection has a performance loss compared to coherent transmission detection. And the decoding complexity of non-coherent detection is very high, usually increasing exponentially according to the size of the transmit antenna and constellation diagram. This limits the application of non-coherent transmission detection.

  Therefore, how to provide better system performance under various different mobile environments is a problem to be solved in the current wireless transmission.

  The present invention has been made in view of the above, and in order to provide better system performance even in wireless transmission under various different mobile environments, a signal transmission method is provided in one aspect of the present invention. In one aspect, a signal transmission system and a transmitter and receiver are provided.

  In the signal transmission method according to the present invention, when a transmitter determines a current moving speed mode of a receiver and the moving speed mode is a low speed moving mode, a signal to be transmitted is transmitted using a coding method of a coherent transmission mode. Encoding, when the moving speed mode is the high speed moving mode, encoding a transmission target signal using an encoding method of a non-coherent transmission mode, and transmitting the encoded signal to a receiver.

  The signal transmission system according to the present invention determines a current moving speed mode of a receiver, and when the moving speed mode is a low speed moving mode, encodes a transmission target signal using a coding method of a coherent transmission mode, When the moving speed mode is a high-speed moving mode, a transmitter that encodes a transmission target signal using an encoding method of a non-coherent transmission mode, and transmits the encoded signal to the receiver; and And a receiver that decodes the received signal using a decoding method corresponding to the encoding method.

  The transmitter according to the present invention is determined by a speed mode determination module for determining whether a current movement speed mode of the receiver is a low speed movement mode or a high speed movement mode, and the speed mode determination module. When the movement speed mode is the low-speed movement mode, the first encoding module that encodes the transmission target signal using the encoding method of the coherent transmission mode, and the movement speed mode determined by the speed mode determination module is the high-speed movement. In the case of the mode, the second encoding module that encodes the transmission target signal using the encoding method of the non-coherent transmission mode and the signal encoded by the first encoding module or the second encoding module are received. A signal transmission module for transmitting to the machine.

  The receiver according to the present invention receives the signal from the transmitter, and determines that the encoding method of the signal is an encoding method in a coherent transmission mode, and transmits the signal to the first decoding module. , When it is determined that the signal encoding method is a non-coherent transmission mode encoding method, the signal receiving module that transmits the signal to the second decoding module; and the signal transmitted from the signal receiving module A first decoding module for decoding using a decoding scheme in a coherent detection mode, and a second decoding for decoding a signal transmitted from the signal receiving module using a decoding scheme in a non-coherent detection mode Module.

  As can be seen from the above solution, in the embodiments of the present invention, self-adaptive signal transmission can be realized by encoding transmission target data using different encoding schemes at different moving speeds of the receiver. . In this self-applied signal transmission, coherent transmission detection technology with better performance is used in a low-speed moving environment, but by using non-coherent transmission detection technology that does not require channel estimation in a high-speed moving environment. The solutions in the embodiments of the present invention can obtain better performance even in various different mobile environments.

  Also, the embodiment of the present invention reduces the complexity of decoding when using non-coherent transmission detection technology in a high-speed moving environment by providing two types of simplified differential space-time coding. Can do.

3 is an exemplary flowchart of a signal transmission method according to an embodiment of the present invention. It is a figure which shows the 1st type differential space-time encoding method in the Example of this invention. In the Example of this invention, it is a figure for demonstrating a 1st type differential space-time coding method by giving an example. It is a figure which shows the 2nd type differential space-time encoding method in the Example of this invention. In the Example of this invention, it is a figure for demonstrating a 2nd type differential space-time coding method by giving an example. It is an exemplary block diagram of the signal transmission system in the Example of this invention.

  In order to further clarify the objects, solutions and merits of the present invention, the present invention will be described in more detail below with reference to examples and drawings.

  FIG. 1 is an exemplary flowchart of a signal transmission method according to an embodiment of the present invention. As shown in FIG. 1, this flow includes the following steps.

  In step 101, the transmitter determines the current moving speed mode of the receiver, and if the moving speed mode is the low speed moving mode, the process proceeds to step 102, and if the moving speed mode is the high speed moving mode, step 103 Proceed to

  In this step, the moving speed mode of the receiver can be divided into a low speed moving mode and a high speed moving mode. When the moving speed mode of the receiver is specifically determined, it may be determined by the exchange between the receiver and the transmitter. At this time, the transmitter may determine the current moving speed mode of the receiver based on the feedback information of the receiver. Alternatively, it may be determined in cooperation with the transmitter by a third party module. Here, there are at least two types of determination methods as described below when the determination is made by the exchange between the receiver and the transmitter.

Method 1:
The receiver detects its current moving speed, compares the detected current moving speed with a predetermined speed threshold, and if the current moving speed is higher than the speed threshold, its own current moving speed If the mode is determined to be a high speed movement mode, and the current movement speed is not higher than the speed threshold, the current movement speed mode is determined to be a low speed movement mode, and the determined current movement speed mode is determined. To the transmitter, and the transmitter determines the current moving speed mode of the receiver based on the instruction of the receiver.

  Here, when the receiver indicates the determined current traveling speed mode to the transmitter, 1 bit of information is used to save the determined current traveling speed mode in order to save system resources. You may be instructed to. For example, 1 is used to represent the low speed movement mode, and 0 is used to denote the high speed movement mode.

Method 2:
The receiver detects its current travel speed, instructs the transmitter on the detected current travel speed, and the transmitter compares the current travel speed detected by the receiver with a predetermined speed threshold. When the current moving speed is higher than the speed threshold, the receiver determines that the current moving speed mode of the receiver is a high speed moving mode, and when the current moving speed is not higher than the speed threshold, It is determined that the current movement speed mode is the low speed movement mode.

  In the above two types of methods, the receiver may periodically detect its current moving speed according to a predetermined cycle, or when the receiver satisfies the set trigger condition, The current moving speed may be detected.

  In step 102, the signal to be transmitted is encoded using the encoding method in the coherent transmission mode.

  In this step, the coherent transmission mode encoding scheme may be any coherent transmission mode encoding scheme in the prior art, for example, space-time encoding. In space-time coding, that is, after the input information bits are modulated, the information bits are left based on the space-time code coding method to complete space-time coding.

  In addition, the coding method of the coherent transmission mode may be a coding method of various newly added coherent transmission modes.

  In step 103, the transmission target signal is encoded using the encoding method of the non-coherent transmission mode.

  In this step, the non-coherent transmission mode coding scheme may be any non-coherent transmission mode coding scheme in the prior art, for example, various differential space-time coding in the prior art.

  Also, the encoding method for the non-coherent transmission mode may be a coding method for various newly added non-coherent transmission modes.

  In step 104, the encoded signal is transmitted to the receiver.

  After receiving the signal encoded by the transmitter, the receiver decodes the encoded signal using a decoding scheme corresponding to the encoding scheme.

  In concrete implementation, if there is only one selectable encoding method for each of the coherent transmission mode encoding method and the non-coherent transmission mode encoding method, the receiver is determined by itself. The encoding method corresponding to the received signal may be determined based on the current moving speed mode. Alternatively, the transmitter may instruct the receiver about the moving speed mode or encoding method corresponding to the signal encoding, and the receiver may determine the encoding method corresponding to the received signal based on the instruction of the transmitter. Also good. For example, the transmitter may attach one instruction information to the downlink signal in order to explain the encoding method used in the current encoding.

  Coherent transmission mode encoding schemes may have more than one selectable encoding scheme and / or non-coherent transmission mode encoding schemes may have more than one selectable encoding scheme. In this case, the receiver may be instructed of an encoding scheme corresponding to the signal encoding, and the receiver may determine the encoding scheme corresponding to the received signal based on the instruction of the transmitter. For example, the transmitter may attach one instruction information to the downlink signal in order to explain the encoding method used in the current encoding.

  In an embodiment of the present invention, in order to reduce the decoding complexity of non-coherent detection, Alamouti space-time code has a high bit rate, a large diversity gain and a low decoding complexity. Considering the above, in step 103 above, two types of simplified differential space-time coding methods are provided based on the Alamouti space-time code.

  FIG. 2 is a diagram showing a first type differential space-time coding method according to the embodiment of the present invention. As shown in FIG. 2, the encoding process of the first type differential space-time code includes the following.

Two channel information bits are input, the two channel information bits are modulated, that is, Alamouti differential space-time coding is performed on the two channel information bits, and the encoded signals s ₁ and s ₂ are obtained. obtain.

を得、符号化行列W_M×2（WはM×Mのユニタリ行列の任意の２列であり、Mは２以上の任意の整数である）を用いて、前記時空間符号行列

をＭ本の送信アンテナに拡張して、送信信号行列

を得る。 With respect to the coded signal s ₁ and s _2, performs pre-coding process including a matrix mapping spatial frequency block coding (SFBC), i.e., Alamouti time to the coded signal s ₁ and s ₂ Perform space-time coding and space-time code matrix

Using the encoding matrix W _{M × 2} (W is an arbitrary two columns of an M × M unitary matrix, and M is an arbitrary integer equal to or greater than 2).

Is expanded to M transmit antennas, and the transmit signal matrix

Get.

  Hereinafter, the above process will be described with reference to an example of the case of binary phase shift (BPSK) modulation and four transmission antennas. As shown in FIG. 3, the encoding process includes:

を得る。その後、符号化行列W_4×2を用いて、Ａｌａｍｏｕｔｉ時空間符号を４本の送信アンテナに拡張して、送信信号行列

を得る。 Information bits a ₁ and a ₂ are input to perform Alamouti differential space-time coding to obtain encoded signals s ₁ and s ₂ . Then, Alamouti space-time encoding is performed on the encoded signals s ₁ and s ₂ ,

Get. Then, using the encoding matrix W _{4 × 2} , the Alamouti space-time code is expanded to four transmission antennas, and the transmission signal matrix

Get.

  As can be seen from the above, when using BPSK modulation, two information bits are input every time, but when using quadrature phase shift (QPSK) modulation, four information bits are input every time, that is, two information bits per channel. Is a bit.

  FIG. 4 is a diagram showing a second type differential space-time coding method according to the embodiment of the present invention. As shown in FIG. 4, the encoding process of the second type differential space-time code includes the following.

  N / 2 Alamouti differential space-time coding units are provided in advance in correspondence with N (N is an even number of 2 or more) transmission antennas.

Corresponding to each Alamouti differential space-time coding unit, each channel inputs 2 bits of information bits and modulates the input information bits of each channel, that is, each Alamouti differential space-time coding unit itself Are subjected to Alamouti differential space-time coding to obtain encoded signals s ₁ , s ₂ ,..., S _N−1 , s _N.

を得る。 The coded signals s ₁ , s ₂ ,..., S _N−1 , s _N are subjected to space-time block coding (SFBC) + frequency switching transmission diversity (FSTD) space-time coding, that is, precoding. Transmit signal matrix

Get.

  Next, the above process will be described by taking an example of the case of BPSK modulation and four transmission antennas. As shown in FIG. 5, the encoding process includes:

  Two Alamouti differential space-time coding units are provided in advance corresponding to the four transmission antennas.

を得る。 Information bits a ₁ and a ₂ are input to perform Alamouti differential space-time coding to obtain encoded signals s ₁ and s ₂ . Information bits a ₃ and a ₄ are input and Alamouti differential space-time coding is performed to obtain encoded signals s ₃ and s ₄ . Thereafter, SFBC + FSTD space-time coding is performed on the encoded signals s ₁ , s ₂ , s _3, and s ₄ to obtain a transmission signal matrix

Get.

  As can be seen from the above, when BPSK modulation is used, four information bits are inputted every time, but when QPSK modulation is used, eight information bits are inputted every time, that is, four information bits per channel.

を初期設定する。 Next, similarly, taking BPSK modulation as an example, the Alamouti differential space-time encoding process in the above-described two types of differential space-time encoding methods will be described in detail.

Is initialized.

になる。ここで、ＡおよびＢは入力情報ビットによって決定され、入力情報ビットがa₁およびa₂であるとき、相応のＡおよびＢを算出して、s₃およびs₄を得ることができる。入力情報ビットa₃およびa₄に基づいて、新しいＡおよびＢを得、

によって、s₅およびs₆を算出することができる。パラメータＡ、Ｂは、数式

によって算出することができる。ここで、Map(・)はビットからシンボルへのマッピングを表す。 When t = 1

become. Here, A and B are determined by input information bits. When the input information bits are a ₁ and a ₂ , s ₃ and s ₄ can be obtained by calculating corresponding A and B. Based on the input information bits a ₃ and a ₄ , new A and B are obtained,

S ₅ and s ₆ can be calculated. Parameters A and B are mathematical expressions

Can be calculated. Here, Map (•) represents a mapping from bits to symbols.

であり、現在の入力ビットが（１ ０）であると、ビット（１ ０）がシンボル（−１ １）にマッピングされるため、A=0、B=1を得る。そうすると、

になる。 For example, the signal at the previous time is

If the current input bit is (1 0), since bit (1 0) is mapped to symbol (−1 1), A = 0 and B = 1 are obtained. Then

become.

  In response, the receiver receives a signal encoded using the first type differential space-time code or the second type differential space-time code from the transmitter, and then performs a corresponding decoding method. And performing differential decoding in the frequency domain between two consecutive frames of received signals. For the sake of clarity, the decoding methods corresponding to the above two types of encoding methods will now be described in detail, taking the case of BPSK modulation, four transmission antennas and one reception antenna as an example.

  The decoding method of the first type differential space-time code includes the following.

であるとすると、受信信号はR=HC+Nになる（Nは雑音行列である）。 Suppose the channel matrix is H = (h ₁₁ h ₁₂ h ₁₃ h ₁₄ ), and the transmission signal matrix is

, The received signal is R = HC + N (N is a noise matrix).

であり、時刻２の受信信号が

である。 Received signal at time 1

And the received signal at time 2 is

It is.

There is a relationship between the encoded signals s ₃ and s ₄ , s ₁ and s _2, and transmission information bits, and there is also an intrinsic relationship between the received signals r ₁ , r ₂ , r ₃ and r ₄ . Received signals r ₁ , r ₂ , r ₃ and r ₄ are processed to obtain variables R ₁ and R ₂ .

上式において、N'およびN''は雑音信号であり、N'''およびN''''は雑音関連信号であり、Vは(AB)からなるベクトル集合である。上式から(AB)を算出する。 R ₁ and R ₂ can be considered to be scaled with the same size for A and B. Therefore, maximum likelihood estimates of A and B can be obtained.

In the above equation, N ′ and N ″ are noise signals, N ′ ″ and N ″ ″ are noise related signals, and V is a vector set consisting of (AB). Calculate (AB) from the above equation.

  Since there is a one-to-one mapping relationship between the vector (AB) and the transmission information bits, it is possible to obtain the transmission information bits from (AB) and complete the decoding.

  The decoding method of the second type differential space-time code includes the following.

であるとすると、受信信号はR=HC+Nになる（Nは雑音行列である）。 Suppose the channel matrix is H = (h ₁₁ h ₁₂ h ₁₃ h ₁₄ ), and the transmission signal matrix is

, The received signal is R = HC + N (N is a noise matrix).

Further, the received signal may be described as follows.

There is a relationship between the reception signals r ₁ and r ₂ and the transmission signals s ₁ and s _2, and a relationship between r ₅ and r ₆ and the transmission signals s ₅ and s ₆ . In the encoding process, s ₅ and s ₆ are related to the transmission bits on the transmitting side of s ₁ and s ₂ , and between the corresponding received signals r ₅ and r ₆ and r ₁ and r ₂ There is an intrinsic connection.

Calculate the following formula.

Here, N ′ ″ and N ″ ″ are noise related signals. As can be seen from the above equation, R ₁ and R ₂ are scaled sums of the modulo values of the A and B channels, respectively, and have the same scaling factor. Then, maximum likelihood estimation can be performed for A and B from the following equation.

  In the above equation, V is a vector set consisting of (AB). After obtaining (AB), since there is a one-to-one mapping relationship between the vector (AB) and the transmission information bits, it is possible to obtain the transmission information bits from (AB) and complete the decoding.

  In concrete implementation, in the embodiment of the present invention, first, the channel frequency selectivity is determined, and if the channel frequency selectivity is strong, preferably the first type differential space-time coding method is selected, When the channel frequency selectivity is weak, the first type differential space-time coding method may be used, or the second type differential space-time coding method may be used. At this time, the transmitter may instruct the receiver of the currently selected encoding method.

  The signal transmission method in the embodiment of the present invention has been described in detail above. Next, the signal transmission system in the embodiment of the present invention will be described in detail.

  FIG. 6 is an exemplary configuration diagram of a signal transmission system according to an embodiment of the present invention. As shown in FIG. 6, this system determines the current moving speed mode of the receiver, and when the moving speed mode is the low speed moving mode, the system encodes the transmission target signal using the coding scheme of the coherent transmission mode. And when the moving speed mode is a high-speed moving mode, a transmitter that encodes a signal to be transmitted using a coding method of a non-coherent transmission mode and transmits the encoded signal to a receiver; and the transmitter And a receiver that decodes the received signal using a decoding scheme corresponding to the encoding scheme.

  Here, if there is only one selectable encoding method for the coherent transmission mode encoding method and the non-coherent transmission mode encoding method, the receiver determines the current moving speed mode determined by itself. Based on the above, the encoding scheme corresponding to the received signal may be determined, and then the received signal may be decoded using a decoding scheme corresponding to the encoding scheme. Alternatively, the transmitter further instructs the receiver about an encoding scheme or a moving speed mode corresponding to the encoded signal, and the receiver moves to a moving speed mode corresponding to the encoding indicated by the transmitter or An encoding scheme corresponding to the received signal may be determined based on the encoding scheme, and then the received signal may be decoded using a decoding scheme corresponding to the encoding scheme.

  Coherent transmission mode encoding schemes may have more than one selectable encoding scheme and / or non-coherent transmission mode encoding schemes may have more than one selectable encoding scheme. Instructing the receiver about the encoding scheme corresponding to the signal encoding, the receiver determines the encoding scheme corresponding to the received signal based on the instruction of the transmitter, and then decoding corresponding to the encoding scheme The received signal may be decoded using an encoding method.

  In specific implementation, the transmitter may determine the current moving speed mode of the receiver based on the feedback information of the receiver.

  For example, the receiver further detects its current moving speed, compares the detected current moving speed with a predetermined speed threshold, and if the determined current moving speed is higher than the speed threshold, Determining that the current movement speed mode is a high speed movement mode, and if the determined current movement speed is not higher than the speed threshold, determining that the current movement speed mode is a low speed movement mode; The determined current speed mode may be indicated to the transmitter. In response, the transmitter determines the current traveling speed mode of the receiver based on the instruction of the receiver. Here, the receiver may use the 1-bit information to indicate the determined current moving speed mode to the transmitter.

  Alternatively, the receiver may instruct the transmitter of the detected current moving speed after detecting the current moving speed of the receiver. In response, the transmitter compares the received current speed of the receiver with a predetermined speed threshold, and if the current speed is higher than the speed threshold, the current speed mode of the receiver is If it is determined that the current movement speed is not higher than the speed threshold, it is determined that the current movement speed mode of the receiver is the low speed movement mode.

  Corresponding to the method in the present embodiment, when the transmitter encodes the transmission target signal using the encoding method in the non-coherent transmission mode, the differential space-time encoding method shown in FIGS. Can be used. Accordingly, the receiver may perform differential decoding in the frequency domain between two consecutive received signals after determining the encoding method corresponding to the received signal. In concrete implementation, the transmitter first determines the channel frequency selectivity and, if the channel frequency selectivity is strong, preferably selects the first type differential space-time coding method, and selects the channel frequency When the nature is weak, the first type differential space-time coding method may be used, or the second type differential space-time coding method may be used. At this time, the transmitter may instruct the receiver of the currently selected encoding method.

  Specifically, as shown in FIG. 6, the transmitter in the embodiment of the present invention specifically includes a speed mode determination module, a first encoding module, a second encoding module, and signal transmission. A module.

  Here, the speed mode determination module determines whether the current moving speed mode of the receiver is the low speed moving mode or the high speed moving mode. In particular, the speed mode determination module may determine the current moving speed mode of the receiver based on the feedback information of the receiver.

  When the movement speed mode determined by the speed mode determination module is the low-speed movement mode, the first encoding module encodes the transmission target signal using a coherent transmission mode encoding scheme.

  When the moving speed mode determined by the speed mode determining module is the high speed moving mode, the second encoding module encodes the transmission target signal using the encoding method of the non-coherent transmission mode.

  The signal transmission module transmits the signal encoded by the first encoding module or the second encoding module to the receiver.

  Here, the speed mode determination module may directly determine the current speed mode of the receiver based on the current speed mode of movement indicated by the receiver, and the current movement indicated by the receiver. Based on the speed, the current moving speed mode of the receiver may be determined by comparing with a predetermined speed threshold.

  Furthermore, if there is only one selectable encoding method for the coherent transmission mode encoding method and the non-coherent transmission mode encoding method, the signal transmission module transmits a code corresponding to the encoded signal. It is also possible to instruct the receiver about the conversion method or the moving speed mode.

  Coding scheme for coherent transmission mode has more than one selectable coding scheme and / or coding scheme for non-coherent transmission mode has more than one selectable coding scheme and signal transmission module May instruct the receiver of an encoding scheme corresponding to signal encoding.

  In concrete implementation, the second encoding module is used to implement the differential space-time encoding method shown in FIGS. 2 to 5, and according to this, the difference shown in FIGS. 2 and 3 is used. When corresponding to the space-time encoding method, the second encoding module may specifically include a first modulation module and a first precoding module (not shown in FIG. 6).

を得、符号化行列W_M×2（WはM×Mのユニタリ行列の任意の２列であり、Ｍは２以上の任意の整数である）を用いて、前記時空間符号行列

をＭ本の送信アンテナに拡張して、送信信号行列

を得る。 Here, the first modulation module performs Alamouti differential space-time coding on the currently input two-channel information bits to obtain encoded signals s ₁ and s ₂ . The first precoding module performs Alamouti space-time coding on the encoded signals s ₁ and s ₂ obtained by the modulation module to obtain a space-time code matrix

Using the encoding matrix W _{M × 2} (W is an arbitrary two columns of an M × M unitary matrix, and M is an arbitrary integer equal to or greater than 2).

Is expanded to M transmit antennas, and the transmit signal matrix

Get.

  When corresponding to the differential space-time coding method shown in FIGS. 4 and 5, the second coding module may specifically include a second modulation module and a second precoding module (see FIG. 6). Not shown).

を得る。 Here, the second modulation module includes N / 2 Alamouti differential space-time coding units provided in advance corresponding to N (N is an even number of 2 or more) transmission antennas, and each Alamouti Each of the differential space-time coding units performs Alamouti differential space-time coding on the two-channel information bits input thereto, and outputs coded signals s ₁ , s ₂ ,..., S _N−1 , s _N Get. The second precoding module is a space-time code of spatial frequency block coding (SFBC) + frequency switching transmission diversity (FSTD) for the encoded signals s ₁ , s ₂ ,..., S _N−1 , s _N. Transmit signal matrix

Get.

  Alternatively, the second encoding module includes the first modulation module, the first precoding module, the second modulation module, the second precoding module, and the channel frequency selectivity determination module. Also good.

  Here, the channel frequency selectivity determination module determines the channel frequency selectivity, and when the channel frequency selectivity is strong, notifies the first modulation module and the first precoding module to encode the encoding target signal. If the channel frequency selectivity is weak, the first modulation module and the first precoding module, or the second modulation module and the second precoding module are notified to encode the encoding target signal. At this time, the signal transmission module may instruct the receiver of the currently selected encoding method.

  Specifically, as shown in FIG. 6, the receiver in the embodiment of the present invention specifically includes a signal receiving module, a first decoding module, and a second decoding module. Good.

  Here, when the signal receiving module receives the signal from the transmitter and determines that the encoding method of the signal is the encoding method of the coherent transmission mode, the signal receiving module transmits the signal to the first decoding module. If the signal encoding method is determined to be a non-coherent transmission mode encoding method, the signal is transmitted to the second decoding module for decoding.

  The first decoding module decodes the signal transmitted from the signal receiving module using a decoding method in a coherent detection mode.

  The second decoding module decodes the signal transmitted from the signal receiving module using a decoding method in a non-coherent detection mode.

  Further, the receiver may include a speed detection module, a mode determination module, and an information instruction module.

  Here, the speed detection module detects a current moving speed of the receiver.

  The mode determination module compares the current movement speed detected by the speed detection module with a predetermined speed threshold, and if the current movement speed is higher than the speed threshold, its current movement speed mode is a high-speed movement. If the current moving speed is not higher than the speed threshold, it is determined that its current moving speed mode is the low speed moving mode.

  The information instruction module instructs the transmitter about the current traveling speed mode determined by the mode determination module.

  Alternatively, this mode determination module may not be included. At this time, the information instruction module may instruct the current moving speed detected by the speed detection module to the transmitter, and may determine the moving speed mode of the receiver by the transmitter.

  When specifically realized, the signal receiving module receives the current moving speed mode determined by the mode determining module, or the moving speed mode or encoding method corresponding to the encoding indicated by the transmitter. The encoding method corresponding to the signal may be determined.

  Further, in response to the encoding scheme used by the transmitter, the second decoding module may further include a differential space-time decoding module that performs differential decoding in the frequency domain between two consecutive frames of received signals. Good.

  For those skilled in the art, it can be understood that the drawings are only one preferred embodiment, and that the modules or flows in the drawings are not necessarily essential to the practice of the invention.

  For those skilled in the art, the modules in the apparatus according to the embodiment may be arranged in the apparatus according to the embodiment as described in the embodiment, and one or more different from the present embodiment may be made by appropriate changes. It can be understood that it may be located in the device. The modules in the above embodiments may be merged into one module and further divided into a plurality of submodules.

  Some steps in the embodiments of the present invention can be realized using software. The corresponding software program may be stored in a readable storage medium such as an optical disk or a hard disk.

  The above are only preferred embodiments of the present invention and do not limit the protection scope of the present invention. Various modifications, equivalent replacements, improvements and the like made within the spirit and principle of the present invention should all be included in the protection scope of the present invention.

Claims (16)

A signal transmission method comprising:
The transmitter determines the current speed mode of the receiver,
When the moving speed mode is a low speed moving mode, a signal to be transmitted is encoded using a coding method of a coherent transmission mode, and when the moving speed mode is a high speed moving mode, an encoding method of a non-coherent transmission mode is set. To encode the signal to be transmitted,
Send the encoded signal to the receiver,
Look at including it,
Encoding the transmission target signal using the non-coherent transmission mode encoding scheme includes encoding the transmission target signal using a differential space-time encoding scheme,
Encoding the transmission target signal using the differential space-time encoding method,
2 channel information bits are input, Alamouti differential space-time coding is performed on the 2 channel information bits to obtain encoded signals S ₁ and S ₂ ,
Alamouti space-time coding is performed on the coded signals S ₁ and S ₂ to obtain a space-time code matrix.

(Superscript * indicates complex conjugate)
And
Using the encoding matrix W _{M × 2} (W is an arbitrary two columns of an M × M unitary matrix, and M is an arbitrary integer of 2 or more), the space-time code matrix

Is expanded to M transmit antennas, and the transmit signal matrix

Including, including,
A method characterized by that. A signal transmission method comprising:
The transmitter determines the current speed mode of the receiver,
When the moving speed mode is a low speed moving mode, a signal to be transmitted is encoded using a coding method of a coherent transmission mode, and when the moving speed mode is a high speed moving mode, an encoding method of a non-coherent transmission mode is set. To encode the signal to be transmitted,
Send the encoded signal to the receiver,
Including
Encoding the transmission target signal using the non-coherent transmission mode encoding scheme includes encoding the transmission target signal using a differential space-time encoding scheme,
Encoding the transmission target signal using the differential space-time encoding method,
Corresponding to N (N is an even number of 2 or more) transmission antennas, N / 2 Alamouti differential space-time coding units are provided in advance,
Corresponding to each Alamouti differential space-time coding unit, two channels of information bits are inputted, and each Alamouti difference space-time coding unit is respectively at the time of Alamouti difference with respect to the two-channel information bits inputted to itself Perform spatial encoding to obtain encoded signals S ₁ , S ₂ ,..., S _N−1 , S _N ,
The coded signals S ₁ , S ₂ ,..., S _N−1 , S _N are subjected to space-time block coding (SFBC) + frequency switching transmission diversity (FSTD) space-time coding, thereby transmitting signals. matrix

(Superscript * indicates complex conjugate)
Including , including ,
How it characterized in that. A signal transmission method comprising:
The transmitter determines the current speed mode of the receiver,
When the moving speed mode is a low speed moving mode, a signal to be transmitted is encoded using a coding method of a coherent transmission mode, and when the moving speed mode is a high speed moving mode, an encoding method of a non-coherent transmission mode is set. To encode the signal to be transmitted,
Send the encoded signal to the receiver,
Including
Encoding the transmission target signal using the non-coherent transmission mode encoding scheme includes encoding the transmission target signal using a differential space-time encoding scheme,
Encoding the transmission target signal using the differential space-time coding scheme determines channel frequency selectivity, and when the channel frequency selectivity is strong, the first type differential space-time coding scheme is used. Including encoding a transmission target signal and encoding the transmission target signal using the first type differential space-time coding method or the second type differential space-time coding method when the channel frequency selectivity is weak. ,
Encoding the transmission target signal using the first type differential space-time encoding method,
2 channel information bits are input, Alamouti differential space-time coding is performed on the 2 channel information bits to obtain encoded signals S ₁ and S ₂ ,
Alamouti space-time coding is performed on the coded signals S ₁ and S ₂ to obtain a space-time code matrix.

(Superscript * indicates complex conjugate)
And
Using the encoding matrix W _{M × 2} (W is an arbitrary two columns of an M × M unitary matrix, and M is an arbitrary integer of 2 or more), the space-time code matrix

Is expanded to M transmit antennas, and the transmit signal matrix

Including, including
Encoding the transmission target signal using the second type differential space-time coding scheme is as follows.
Corresponding to N (N is an even number of 2 or more) transmission antennas, N / 2 Alamouti differential space-time coding units are provided in advance,
Corresponding to each Alamouti differential space-time coding unit, two channels of information bits are inputted, and each Alamouti difference space-time coding unit is respectively at the time of Alamouti difference with respect to the two-channel information bits inputted to itself Perform spatial encoding to obtain encoded signals S ₁ , S ₂ ,..., S _N−1 , S _N ,
The coded signals S ₁ , S ₂ ,..., S _N−1 , S _N are subjected to space-time block coding (SFBC) + frequency switching transmission diversity (FSTD) space-time coding, thereby transmitting signals. matrix

(Superscript * indicates complex conjugate)
Including, including,
How it characterized in that. The receiver detects its current moving speed, compares the detected current moving speed with a predetermined speed threshold, and if the current moving speed is higher than the speed threshold, its own current moving speed If the mode is determined to be a high speed movement mode, and the current movement speed is not higher than the speed threshold, the current movement speed mode is determined to be a low speed movement mode, and the determined current movement speed mode is determined. Further instructing the transmitter,
The transmitter determining the current moving speed mode of the receiver includes the transmitter determining the current moving speed mode of the receiver based on an instruction of the receiver;
The method according to any one of claims 1 to 3 , wherein: Indicating the determined current traveling speed mode to the transmitter includes instructing the transmitter to determine the determined current traveling speed mode using 1-bit information. Item 5. The method according to Item 4 . The receiver further comprising detecting its current moving speed and instructing the transmitter of the detected current moving speed;
The transmitter determines the current moving speed mode of the receiver when the transmitter compares the received moving speed of the receiver with a predetermined speed threshold, and the current moving speed is the speed. If it is higher than the threshold, it is determined that the current moving speed mode of the receiver is the high speed moving mode, and if the current moving speed is not higher than the speed threshold, the current moving speed mode of the receiver is the low speed moving mode. Including determining that there is,
The method according to any one of claims 1 to 3 , wherein: The receiver receives the signal from the transmitter and receives it based on the current moving speed mode determined by itself or the moving speed mode or encoding method corresponding to the encoding indicated by the transmitter. determines a coding scheme corresponding to the signal, by using a decoding method corresponding to the encoding method, decoding the received signals, further to any of the claims 1-3, characterized in that it comprises 1 The method according to item . A transmitter instructing a receiver of an encoding scheme corresponding to the encoded signal;
A receiver receives the signal from the transmitter, determines an encoding scheme corresponding to the signal based on an encoding scheme designated by the transmitter, and uses a decoding scheme corresponding to the encoding scheme Decoding the signal
The method of claim 3 further comprising: A signal transmission system,
When the current moving speed mode of the receiver is determined and the moving speed mode is the low speed moving mode, the signal to be transmitted is encoded using the coding method of the coherent transmission mode, and the moving speed mode is the high speed moving mode. In some cases, a transmitter that encodes a signal to be transmitted using an encoding scheme in a non-coherent transmission mode, and transmits the encoded signal to the receiver;
A receiver for receiving a signal from the transmitter and decoding a received signal using a decoding scheme corresponding to an encoding scheme;
It includes,
Encoding the transmission target signal using the non-coherent transmission mode encoding scheme includes encoding the transmission target signal using a differential space-time encoding scheme,
Encoding the transmission target signal using the differential space-time encoding method,
2 channel information bits are input, Alamouti differential space-time coding is performed on the 2 channel information bits to obtain encoded signals S ₁ and S ₂ ,
Alamouti space-time coding is performed on the coded signals S ₁ and S ₂ to obtain a space-time code matrix.

(Superscript * indicates complex conjugate)
And
Using the encoding matrix W _{M × 2} (W is an arbitrary two columns of an M × M unitary matrix, and M is an arbitrary integer of 2 or more), the space-time code matrix

Is expanded to M transmit antennas, and the transmit signal matrix

Including, including,
A system characterized by that. A signal transmission system,
When the current moving speed mode of the receiver is determined and the moving speed mode is the low speed moving mode, the signal to be transmitted is encoded using the coding method of the coherent transmission mode, and the moving speed mode is the high speed moving mode. In some cases, a transmitter that encodes a signal to be transmitted using an encoding scheme in a non-coherent transmission mode, and transmits the encoded signal to the receiver;
A receiver for receiving a signal from the transmitter and decoding a received signal using a decoding scheme corresponding to an encoding scheme;
Including
Encoding the transmission target signal using the non-coherent transmission mode encoding scheme includes encoding the transmission target signal using a differential space-time encoding scheme,
Encoding the transmission target signal using the differential space-time encoding method,
Corresponding to N (N is an even number of 2 or more) transmission antennas, N / 2 Alamouti differential space-time coding units are provided in advance,
Corresponding to each Alamouti differential space-time coding unit, two channels of information bits are inputted, and each Alamouti difference space-time coding unit is respectively at the time of Alamouti difference with respect to the two-channel information bits inputted to itself. Perform spatial encoding to obtain encoded signals S ₁ , S ₂ ,..., S _N−1 , S _N ,
The coded signals S ₁ , S ₂ ,..., S _N−1 , S _N are subjected to space-time block coding (SFBC) + frequency switching transmission diversity (FSTD) space-time coding to obtain a transmission signal matrix

(Superscript * indicates complex conjugate)
Including, including,
A system characterized by that. A signal transmission system,
When the current moving speed mode of the receiver is determined and the moving speed mode is the low speed moving mode, the signal to be transmitted is encoded using the coding method of the coherent transmission mode, and the moving speed mode is the high speed moving mode. In some cases, a transmitter that encodes a signal to be transmitted using an encoding scheme in a non-coherent transmission mode, and transmits the encoded signal to the receiver;
A receiver for receiving a signal from the transmitter and decoding a received signal using a decoding scheme corresponding to an encoding scheme;
Including
Encoding the transmission target signal using the non-coherent transmission mode encoding scheme includes encoding the transmission target signal using a differential space-time encoding scheme,
Encoding the transmission target signal using the differential space-time coding scheme determines channel frequency selectivity, and when the channel frequency selectivity is strong, the first type differential space-time coding scheme is used. Including encoding a transmission target signal and encoding the transmission target signal using the first type differential space-time coding method or the second type differential space-time coding method when the channel frequency selectivity is weak. ,
Encoding the transmission target signal using the first type differential space-time encoding method,
2 channel information bits are input, Alamouti differential space-time coding is performed on the 2 channel information bits to obtain encoded signals S ₁ and S ₂ ,
Alamouti space-time coding is performed on the coded signals S ₁ and S ₂ to obtain a space-time code matrix.

(Superscript * indicates complex conjugate)
And
Using the encoding matrix W _{M × 2} (W is an arbitrary two columns of an M × M unitary matrix, and M is an arbitrary integer of 2 or more), the space-time code matrix

Is expanded to M transmit antennas, and the transmit signal matrix

Including, including
Encoding the transmission target signal using the second type differential space-time coding scheme is as follows.
Corresponding to N (N is an even number of 2 or more) transmission antennas, N / 2 Alamouti differential space-time coding units are provided in advance,
Corresponding to each Alamouti differential space-time coding unit, two channels of information bits are inputted, and each Alamouti difference space-time coding unit is respectively at the time of Alamouti difference with respect to the two-channel information bits inputted to itself. Perform spatial encoding to obtain encoded signals S ₁ , S ₂ ,..., S _N−1 , S _N ,
The coded signals S ₁ , S ₂ ,..., S _N−1 , S _N are subjected to space-time block coding (SFBC) + frequency switching transmission diversity (FSTD) space-time coding, thereby transmitting signals. matrix

(Superscript * indicates complex conjugate)
Including, including,
A system characterized by that. The receiver further detects its current moving speed, compares the detected current moving speed with a predetermined speed threshold, and if the current moving speed is higher than the speed threshold, If the current moving speed mode is not higher than the speed threshold, the current moving speed mode is determined to be the low speed moving mode, and the determined current speed is determined to be the high speed moving mode. Instruct the transmitter to move speed mode,
The transmitter determines a current moving speed mode of the receiver based on an instruction of the receiver;
The system according to any one of claims 9 to 11, characterized in that: A transmitter,
A speed mode determination module for determining whether the current moving speed mode of the receiver is a low speed moving mode or a high speed moving mode;
A first encoding module that encodes a transmission target signal using an encoding scheme of a coherent transmission mode when the movement speed mode determined by the speed mode determination module is a low-speed movement mode;
When the moving speed mode determined by the speed mode determining module is a high speed moving mode, a second encoding module that encodes a transmission target signal using an encoding method of a non-coherent transmission mode;
A signal transmission module for transmitting a signal encoded by the first encoding module or the second encoding module to a receiver;
Only including,
The second encoding module includes:
A first modulation module that performs Alamouti differential space-time coding on the currently input two-channel information bits to obtain encoded signals S ₁ and S ₂ ;
A space-time code matrix is obtained by performing Alamouti space-time coding on the coded signals S ₁ and S ₂ obtained by the first modulation module.

(Superscript * indicates complex conjugate)
Using the encoding matrix W _{M × 2} (W is an arbitrary two columns of an M × M unitary matrix, and M is an arbitrary integer greater than or equal to 2).

Is expanded to M transmit antennas, and the transmit signal matrix

A first precoding module to obtain
A transmitter characterized by that. A transmitter,
A speed mode determination module for determining whether the current moving speed mode of the receiver is a low speed moving mode or a high speed moving mode;
A first encoding module that encodes a transmission target signal using an encoding scheme of a coherent transmission mode when the movement speed mode determined by the speed mode determination module is a low-speed movement mode;
When the moving speed mode determined by the speed mode determining module is a high speed moving mode, a second encoding module that encodes a transmission target signal using an encoding method of a non-coherent transmission mode;
A signal transmission module for transmitting a signal encoded by the first encoding module or the second encoding module to a receiver;
Including
The second encoding module includes:
Corresponding to N (N is an even number of 2 or more) transmission antennas, N / 2 Alamouti differential space-time coding units provided in advance are provided, and each Alamouti differential space-time coding unit includes A second modulation module that performs Alamouti differential space-time coding on two-channel information bits input to itself to obtain encoded signals S ₁ , S ₂ ,..., S _N−1 , S _N ;
The coded signals S ₁ , S ₂ ,..., S _N−1 , S _N are subjected to space-time block coding (SFBC) + frequency switching transmission diversity (FSTD) space-time coding, thereby transmitting signals. matrix

(Superscript * indicates complex conjugate)
The obtained comprising a second precoding module, a,
Shin machine sending you, characterized in that. A transmitter,
A speed mode determination module for determining whether the current moving speed mode of the receiver is a low speed moving mode or a high speed moving mode;
A first encoding module that encodes a transmission target signal using an encoding scheme of a coherent transmission mode when the movement speed mode determined by the speed mode determination module is a low-speed movement mode;
When the moving speed mode determined by the speed mode determining module is a high speed moving mode, a second encoding module that encodes a transmission target signal using an encoding method of a non-coherent transmission mode;
A signal transmission module for transmitting a signal encoded by the first encoding module or the second encoding module to a receiver;
Including
The second encoding module includes:
If the channel frequency selectivity is determined and the channel frequency selectivity is strong, the first modulation module and the first precoding module are notified to encode the signal to be encoded, and if the channel frequency selectivity is weak, A channel frequency selectivity determination module for notifying the first modulation module and the first precoding module or the second modulation module and the second precoding module to encode the encoding target signal;
A first modulation module that performs Alamouti differential space-time coding on the currently input two-channel information bits to obtain encoded signals S ₁ and S ₂ ;
A space-time code matrix is obtained by performing Alamouti space-time coding on the coded signals S ₁ and S ₂ obtained by the first modulation module.

(Superscript * indicates complex conjugate)
Using the encoding matrix W _{M × 2} (W is an arbitrary two columns of an M × M unitary matrix, and M is an arbitrary integer greater than or equal to 2).

Is expanded to M transmit antennas, and the transmit signal matrix

A first precoding module to obtain
Corresponding to N (N is an even number of 2 or more) transmission antennas, N / 2 Alamouti differential space-time coding units provided in advance are provided, and each Alamouti differential space-time coding unit includes A second modulation module that performs Alamouti differential space-time coding on two-channel information bits input to itself to obtain encoded signals S ₁ , S ₂ ,..., S _N−1 , S _N ;
The coded signals S ₁ , S ₂ ,..., S _N−1 , S _N are subjected to space-time block coding (SFBC) + frequency switching transmission diversity (FSTD) space-time coding, thereby transmitting signals. matrix

(Superscript * indicates complex conjugate)
A second precoding module to obtain
The signal transmission module further instructs a receiver on an encoding scheme corresponding to the encoded signal;
Shin machine sending you, characterized in that. The transmission according to any one of claims 13 to 15, wherein the signal transmission module further instructs a receiver about an encoding scheme or a moving speed mode corresponding to the encoded signal. Machine.

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