An adaptive spatial transmission method and system suitable for unidirectional channels

Abstract

The application relates to the technical field of one-way channel communication, and particularly discloses a self-adaptive space transmission method and system suitable for one-way channels, which comprises the following steps: a channel sending end senses a channel state and adjusts a space transmission mode accordingly; source information is encoded by using a fountain code to obtain N encoded packages; the N encoded packages are respectively spread coded according to the space transmission mode to obtain spread coded packages; the spread coded packages are modulated and amplified to serve as sending signals and are sent out; a part of the sending signals is coupled, the coupled signals are analyzed to determine the current channel state, and the space transmission mode is adjusted accordingly. The method and system can switch decoding modes adaptively at the receiving end after the space transmission mode is changed at the sending end, so that the self-adaptive space transmission of information of one-way channels is realized, and the method and system are suitable for absolute one-way communication link systems containing multiple antennas.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of one-way channel communication, and in particular to an adaptive spatial transmission method and system suitable for one-way channel. BACKGROUND

[0002] One-way channel mainly exists in satellite communication, deep space communication and broadcast television communication system, etc. Some of these systems are one-way by nature, and some can be approximated as one-way system due to their sensitivity to time delay. In order to ensure the reliability of communication, the spacecraft usually arranges multiple antennas on its surface, so that electromagnetic waves can be transmitted through multiple spatial channels between the transceiver. In this way, the transmission capacity of the transmission link can be effectively improved by fully utilizing the spatial channel resources without increasing the spectrum resources.

[0003] The multi-antenna system can maximize the utilization of channel spatial resources by changing the spatial transmission mode, i.e. the content of information transmitted by each antenna on the surface of the spacecraft. The space-time transmission mode mainly includes spatial diversity and spatial multiplexing. Spatial diversity and multiplexing both increase the number of information transmission channels by arranging multiple antennas at the transceiver of the channel. Spatial diversity transmits multiple copies of the same information between different channels to improve the transmission reliability of the link; spatial multiplexing transmits multiple independent information between different channels to improve the transmission efficiency and capacity of the link. The choice of spatial diversity and spatial multiplexing mode is mainly based on the communication condition of the channel at each antenna. Generally, when the channel condition is good, the information transmission error rate is low, and the system can use spatial multiplexing transmission mode to improve the transmission efficiency of the system; when the channel condition is poor, the information transmission error rate is high, and the system can use spatial diversity transmission mode to improve the transmission reliability of the system.

[0004] In the traditional communication process, the receiving end usually senses the communication condition of the channel, then informs the sending end through the feedback channel, and the sending end changes the spatial transmission mode according to the channel condition. Therefore, in this mode, both the receiving end and the sending end can know the currently used spatial transmission mode. However, for one-way channel, there is no feedback loop in the channel. At this time, the channel state can only be sensed by the sending end through relevant measurable parameters, and the channel communication quality is divided into different levels according to the real-time measurement of the standing wave ratio of the transmitting antenna. Finally, the spatial transmission mode (spatial diversity or spatial multiplexing) of the sending end is adjusted according to the channel condition, but the receiving end cannot know the currently used transmission mode in real time, which will cause decoding error of the receiving end if the traditional transmission mode is used. SUMMARY

[0005] In view of the technical problems in the prior art, the present application provides an adaptive spatial transmission method and system suitable for one-way channel.

[0006] The application comprises an adaptive spatial transmission method suitable for a one-way channel, comprising:

[0007] The channel sending end senses the channel state and adjusts the spatial transmission mode accordingly;

[0008] The source information is encoded by a fountain code to obtain N encoded packets;

[0009] The N encoded packets are respectively spread coded according to the spatial transmission mode to obtain spread coded packets;

[0010] The spread coded packets are modulated and amplified to be sent as sending signals;

[0011] The coupled sending signals are analyzed to determine the current channel state and adjust the spatial transmission mode accordingly.

[0012] Further, the spatial transmission mode comprises spatial diversity and spatial multiplexing.

[0013] Further, the spread coding of the N encoded packets according to the spatial transmission mode comprises:

[0014] If the spatial transmission mode is spatial diversity, the N encoded packets are respectively spread coded by a pseudo code "sequence 0";

[0015] If the spatial transmission mode is spatial multiplexing, the N encoded packets are respectively spread coded by a pseudo code "sequence n" according to the number n of the transmitting antenna corresponding to the encoded packet; n is a positive integer greater than 1.

[0016] The application further comprises an adaptive spatial transmission method suitable for a one-way channel, comprising:

[0017] The channel receiving end receives the receiving signals, and down-converts and demodulates the receiving signals;

[0018] The receiving signals are decoded according to the spatial diversity mode;

[0019] It is judged whether the decoding is successful, if yes, then

[0020] The first decoded information is outputted and decoded by a fountain code; if not, then

[0021] The receiving signals are packet decoded according to the spatial multiplexing mode, and a plurality of second decoded information is outputted;

[0022] The plurality of second decoded information is decoded by a fountain code cascade decoding.

[0023] Further, the decoding of the receiving signals according to the spatial diversity mode comprises:

[0024] The received signal is despread by taking the sequence 0 as a despread sequence number.

[0025] Further, the received signal is packet decoded in a spatial multiplexing manner, comprising:

[0026] The received signal is packeted into received signal 1, received signal 2, …, received signal n according to the receiving order; n is the number of transmitting antennas set by the channel transmitting end;

[0027] The received signal 1, received signal 2, …, received signal n are despread respectively by taking the sequence 1 to the sequence n as a despread sequence number.

[0028] Further, the second decoding information is cascade decoded by a fountain code, comprising:

[0029] Finding the row with weight 1 in the encoding generation matrix G corresponding to all the second decoding information;

[0030] Adding all the rows with weight 1 in the encoding generation matrix G corresponding to the second decoding information;

[0031] The fountain decoding is performed according to the encoding generation matrix G to obtain the source information corresponding to each second decoding information. The application further comprises an adaptive spatial transmission system suitable for a one-way channel, which comprises a channel transmitting end and a channel receiving end; wherein:

[0032] The channel transmitting end comprises a fountain code encoding module, a spread spectrum encoding module, a modulation module, a coupler module and a transmitting antenna, the fountain code encoding module is connected with the spread spectrum encoding module, the spread spectrum encoding module is connected with the modulation module, the modulation module is connected with the coupler module, and the coupler module is connected with the transmitting antenna; the fountain code encoding module is used for fountain code encoding the source information to obtain N encoding packets; the spread spectrum encoding module is used for spread spectrum encoding the N encoding packets respectively according to the spatial transmission mode to obtain spread spectrum encoding packets; the modulation module is used for modulating and amplifying the spread spectrum encoding packets as a transmitting signal; the coupler module is used for coupling part of the transmitting signal, analyzing the coupled signal, determining the current channel state and adjusting the spatial transmission mode correspondingly; and the transmitting antenna is used for transmitting the transmitting signal to the channel receiving end.

[0033] The channel receiving end comprises a receiving antenna, a frequency conversion demodulation module, a space diversity decoding module, a space multiplex decoding module and a fountain code decoding module, the receiving antenna is connected with the frequency conversion demodulation module, the frequency conversion demodulation module is connected with the space diversity decoding module and the space multiplex decoding module, and the space diversity decoding module and the space multiplex decoding module are connected with the fountain code decoding module; the receiving antenna is used for collecting a receiving signal; the frequency conversion demodulation module is used for down-converting and demodulating the receiving signal; the space diversity decoding module is used for decoding the receiving signal in a space diversity manner and outputting first decoding information; the space multiplex decoding module is used for decoding the receiving signal in a space multiplex manner and outputting a plurality of second decoding information; and the fountain code decoding module is used for decoding the first decoding information and cascade decoding the plurality of second decoding information.

[0034] Further, the spread spectrum coding module comprises a space diversity spread spectrum coding unit and a space multiplex spread spectrum coding unit, wherein:

[0035] The space diversity spread spectrum coding unit is used for spread spectrum coding of the coding packet by using the pseudo code "sequence 0";

[0036] The space multiplex spread spectrum coding unit is used for spread spectrum coding of the coding packet by using the pseudo code "sequence n" according to the number n of the transmitting antenna corresponding to the coding packet; n is a positive integer greater than 1.

[0037] Further, the space diversity decoding module is used for checking the receiving signal by using "sequence 0" as a despread sequence number; the space multiplex decoding module is used for dividing the receiving signal into receiving signal 1, receiving signal 2,..., receiving signal n according to the receiving order; n is the number of the transmitting antennas provided by the channel transmitting end; and the receiving signal 1, the receiving signal 2,..., the receiving signal n are respectively despread by using "sequence 1" to "sequence n" as the despread sequence numbers.

[0038] The adaptive space transmission method and system suitable for a one-way channel of the present application can realize adaptive switching of the decoding mode of the receiving end after the space transmission mode of the transmitting end is changed, thereby realizing adaptive space transmission of information of the one-way channel and being suitable for an absolute one-way communication link system containing multiple antennas. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0040] Figure 1 A step flow chart of an adaptive space transmission method suitable for a one-way channel according to an embodiment of the present application;

[0041] Figure 2 A step flow chart of another adaptive space transmission method suitable for a one-way channel according to an embodiment of the present application;

[0042] Figure 3 A flow chart of another adaptive space transmission method suitable for a one-way channel according to an embodiment of the present application;

[0043] Figure 4 A simulation example diagram according to an embodiment of the present application;

[0044] Figure 5 A structure composition diagram of an adaptive space transmission system suitable for a one-way channel according to an embodiment of the present application. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0046] The embodiments of the present application provide an adaptive space transmission method suitable for a one-way channel, as shown in Figure 1 which includes the following steps:

[0047] Step S101: The channel sending end senses the channel state and adjusts the space transmission mode correspondingly.

[0048] The space transmission mode of the embodiments of the present application includes two kinds, which are space diversity and space multiplexing. After the channel sending end senses the channel state, the space transmission mode is adjusted to be space diversity or space multiplexing.

[0049] Step S102: The source information is encoded by a fountain code to obtain N encoded packets.

[0050] The process of adopting the fountain code encoding in the present embodiment can be referred to the existing mode by those of ordinary skill in the art. The fountain code (also called as a code rate erasure code) is a kind of erasure code, which has the ability to generate an infinite sequence of encoded symbols from a given set of source symbols, and in an ideal case, only an arbitrary subset of encoded symbols with the same size or slightly larger than the source symbols is needed to recover the source symbols.

[0051] The application range of fountain code can be summarized as follows: ① high-speed large file transmission in wide area network, Internet, satellite network. The forward error correction coding represented by RS is realized by hardware, and is designed according to the requirement of protecting small data blocks, mainly detecting and correcting multiple bits or single bit damaged. The LT code aims to protect large files, and the technology is realized by software, and the speed is very fast. Without the influence of network delay of TCP on throughput, the fountain code can provide large file transmission close to network bandwidth speed in Internet, wireless network, mobile network and satellite network. ② providing perfect quality streaming media on-demand or broadcast in wireless network and mobile network. The fountain code technology can be used to process the most headache streaming video, audio, video game, MP3 file and the like in Internet, and can provide perfect quality streaming media on-demand or broadcast. ③ providing reliable data broadcast without feedback channel in 3G mobile network, digital television broadcast network, telecommunication multicast network and satellite broadcast system. Since no feedback is needed, the growth of the number of users has no effect on the sender, and the sender can serve any number of users.

[0052] Step S103: spreading code encoding is performed on the N encoded packets respectively according to the spatial transmission mode, to obtain spreading code packets.

[0053] Under the two spatial transmission modes of spatial diversity and spatial multiplexing, different spreading code encoding modes are used, which are as follows:

[0054] If the spatial transmission mode is spatial diversity, pseudo code "sequence 0" is used to perform spreading code encoding on the N encoded packets respectively;

[0055] If the spatial transmission mode is spatial multiplexing, according to the number n of the transmitting antenna corresponding to the encoded packet, pseudo code "sequence n" is used to perform spreading code encoding on the N encoded packets respectively; n is a positive integer greater than 1. That is, if the encoded packet is transmitted by transmitting antenna 1, pseudo code "sequence 1" is used to perform spreading code encoding on the encoded packet, if the encoded packet is transmitted by transmitting antenna 2, pseudo code "sequence 2" is used to perform spreading code encoding on the encoded packet, and so on, if the encoded packet is transmitted by transmitting antenna n, pseudo code "sequence n" is used to perform spreading code encoding on the encoded packet.

[0056] Step S104: the spreading code packets are modulated and amplified to be sent as a sending signal.

[0057] The spreading code packets after spreading code encoding are modulated and amplified, and are sent out by the corresponding transmitting antenna.

[0058] The method of the embodiment of the application further comprises:

[0059] Step S105: the coupling part sends a signal, analyzes the coupling signal, determines the current channel state and adjusts the spatial transmission mode accordingly.

[0060] A part of the transmission signal sent by the transmitting antenna is coupled to evaluate the channel state and then adjust the spatial transmission mode (i.e. select "spatial diversity" or "spatial multiplexing") adaptively.

[0061] Another adaptive spatial transmission method suitable for one-way channel of the embodiment of the present application is shown in Figure 2 and Figure 3 and includes the following steps:

[0062] Step S201: the channel receiving end collects a received signal and performs frequency down-conversion and demodulation on the received signal.

[0063] The received signal in the step of the present application is processed and sent by the channel transmitting end of the previous embodiment. When the channel transmitting end of the first embodiment of the present application switches between the two spatial transmission modes of spatial diversity and spatial multiplexing, the present embodiment first performs frequency down-conversion and demodulation on the collected received signal, and then executes step S202.

[0064] Step S202: decode the received signal in the mode of spatial diversity.

[0065] The present embodiment sets the decoding system of spatial diversity as a priority decoding system, and first decodes the received signal in the mode of spatial diversity, which can be specifically: spreading the received signal with "sequence 0" as the spreading sequence number.

[0066] In the previous embodiment of the present application, the code packet is spread coded with the pseudo code "sequence 0", so when decoding in the mode of spatial diversity, the present embodiment still uses "sequence 0" as the spreading sequence number.

[0067] Step S203: determine whether the decoding is successful.

[0068] If yes, it means that the current channel transmits information in the mode of spatial diversity, so after spreading the received signal with "sequence 0" as the spreading sequence number, step S204 is executed to output the first decoded information, which is the information contained in the spread received signal. If the decoding is not successful, it means that the current channel transmits information in the mode of spatial multiplexing, and spreading the received signal with "sequence 0" as the spreading sequence number will not have a corresponding output, so step S205 is continued.

[0069] Step S204: output the first decoded information and perform fountain code decoding.

[0070] The fountain code decoding mode is not described in detail here, and those skilled in the art can realize it according to the existing experience.

[0071] Step S205: The received signal is packet-decoded in a spatial multiplexing manner, and a plurality of second decoding information is output.

[0072] In the case where it is determined that the current channel does not use the spatial diversity manner for information transmission, the received signal is packet-decoded in a spatial multiplexing manner, and a plurality of second decoding information is output. Specifically, step S205 includes:

[0073] The received signal is packet-decoded in a spatial multiplexing manner, and a plurality of second decoding information is output. Specifically, step S205 includes:

[0074] The received signal is packet-decoded in a spatial multiplexing manner, and a plurality of second decoding information is output. Specifically, step S205 includes:

[0075] Step S206: The plurality of second decoding information is cascade-decoded by using the fountain code.

[0076] In order to improve the decoding efficiency of the channel receiving end in the spatial multiplexing transmission manner, the embodiment of the application designs a fountain code cascade decoding manner, specifically: finding a row with a weight of 1 in the encoding generation matrix G corresponding to all second decoding information; adding all rows with a weight of 1 in the encoding generation matrix G corresponding to the second decoding information; and performing fountain decoding according to the encoding generation matrix G to obtain the source information corresponding to each second decoding information.

[0077] Taking the BP decoding process as an example, assuming that the transmitted data is x = [x1, x2, …, xn]T, the received data is y = [y1, y2, …, yn]T, and the encoding generation matrix constructed by the channel receiving end is G = [g1, g2, …, gn]T, then k T k T k T

[0078]

[0079] wherein g m is a column vector composed of the mth column of the encoding generation matrix G; an ith row with a weight of 1 is found from the encoding generation matrix G, and the column in which the only element 1 of the row is located is the jth column, and the ith source information is:

[0080] y i = x j (2). ​​​​​​

[0081] After this step of decoding, formula (1) can be further expressed as:

[0082]

[0083] Formula (3) can be further expressed as:

[0084]

[0085] Wherein, y'=y+g j x j ,

[0086] Compared with formula (1), formula (4) is completely consistent with the above two formulas except that the encoding sequence y of the channel receiving end and the encoding generation matrix G are updated. Therefore, as long as the row with weight 1 is continued to be contained in G', the transformation process of formula (1) to formula (4) can be repeated, and new y i can be obtained. As can be seen from the above decoding process, the total decoding efficiency of the BP decoding algorithm mainly depends on the number of rows with weight 1 in the encoding generation matrix G. And Figure 3 In the channel receiving end of formula (4), if n information can be obtained after decoding of the fountain code in channel 1, the n information can be used for decoding of the fountain code in channel 2 and channel 3, which is equivalent to adding n rows with weight 1 to the encoding generation matrix G of channel 2 and channel 3. By the same token, the information obtained by decoding of the fountain code in channel 2 and channel 3 can also supplement the rows with weight 1 to the encoding generation matrix G of the other two channels. The cascade decoding method can effectively reduce the number of iterations in the decoding process.

[0087] The present application combines the above two embodiments, and uses the cascade BP decoding algorithm for simulation experiment. Assuming that the number of source information is 2000, and the encoding redundancy is 0, as shown in Figure 4 , the simulation result of the cascade BP decoding algorithm is shown. The decoding rate of the present channel rapidly increases with the increase of the decoded information obtained from others, so that the cascade fountain code decoding can not only improve the decoding efficiency, but also realize decoding of all information with small transmission redundancy, which is particularly suitable for one-way transmission channels in a poor transmission environment.

[0088] The present application also provides an embodiment of a self-adaptive spatial transmission system suitable for one-way channels, as shown in Figure 5 , the system comprises a channel sending end 10 and a channel receiving end 20; wherein:

[0089] The channel sending end 10 comprises a fountain code encoding module 101, a spread spectrum encoding module 102, a modulation module 103, a coupler module 104 and a transmitting antenna 105, the fountain code encoding module 101 is connected with the spread spectrum encoding module 102, the spread spectrum encoding module 102 is connected with the modulation module 103, the modulation module 103 is connected with the coupler module 104, and the coupler module 104 is connected with the transmitting antenna 105; the fountain code encoding module 101 is used for fountain code encoding of source information to obtain N encoding packets; the spread spectrum encoding module 102 is used for spread spectrum encoding of the N encoding packets respectively according to a space transmission mode to obtain spread spectrum encoding packets; the modulation module 103 is used for modulation and amplification of the spread spectrum encoding packets as a sending signal; the coupler module 104 is used for coupling part of the sending signal, analyzing the coupled signal, determining a current channel state and adjusting the space transmission mode correspondingly; and the transmitting antenna 105 is used for sending the sending signal to a channel receiving end.

[0090] The spread spectrum encoding module 102, the modulation module 103, the coupler module 104 and the transmitting antenna 105 in the embodiment of the application can be provided in plurality and form a plurality of signal processing channels according to the above connection relationship.

[0091] The channel receiving end 20 comprises a receiving antenna 201, a frequency conversion demodulation module 202, a space diversity decoding module 203, a space multiplex decoding module 204 and a fountain code decoding module 205, the receiving antenna 201 is connected with the frequency conversion demodulation module 202, the frequency conversion demodulation module 202 is connected with the space diversity decoding module 203 and the space multiplex decoding module 204, and the space diversity decoding module 203 and the space multiplex decoding module 204 are connected with the fountain code decoding module 205; the receiving antenna 201 is used for collecting a receiving signal; the frequency conversion demodulation module 202 is used for frequency conversion and demodulation of the receiving signal; the space diversity decoding module 203 is used for decoding of the receiving signal in a space diversity mode and output of first decoding information; the space multiplex decoding module 204 is used for packet decoding of the receiving signal in a space multiplex mode and output of a plurality of second decoding information; and the fountain code decoding module 205 is used for fountain code decoding of the first decoding information and fountain code cascade decoding of the plurality of second decoding information.

[0092] Specifically, the spread spectrum encoding module 102 in the embodiment of the application comprises a space diversity spread spectrum encoding unit and a space multiplex spread spectrum encoding unit, wherein: the space diversity spread spectrum encoding unit is used for spread spectrum encoding of an encoding packet by using a pseudo code "sequence 0"; the space multiplex spread spectrum encoding unit is used for spread spectrum encoding of the encoding packet by using a pseudo code "sequence n" according to a number n of a transmitting antenna corresponding to the encoding packet; and n is a positive integer greater than 1.

[0093] Specifically, the spatial diversity decoding module 203 in the embodiment of the present application is configured to perform despreading on the received signal by taking "sequence 0" as a despreading sequence number; the spatial multiplexing decoding module 204 is configured to package the received signal into received signal 1, received signal 2,..., received signal n according to the receiving order; n is the number of the transmitting antennas provided by the channel transmitting end; and the received signal 1, received signal 2,..., received signal n are respectively despread by taking "sequence 1" to "sequence n" as the despreading sequence number.

[0094] The adaptive spatial transmission system suitable for the one-way channel in the embodiment of the present application comprises the modules whose function implementation processes can be referred to the foregoing embodiment of the adaptive spatial transmission method suitable for the one-way channel, and thus will not be described herein.

[0095] The adaptive spatial transmission method and system suitable for the one-way channel in the embodiment of the present application can realize adaptive switching of the decoding mode at the receiving end after the spatial transmission mode is changed at the transmitting end, thereby realizing adaptive spatial transmission of information of the one-way channel and being suitable for the absolute one-way communication link system containing multiple antennas.

[0096] The above has further described the present application by means of specific embodiments, but it should be understood that the specific description herein should not be understood as the limitation on the essence and scope of the present application, and various modifications made to the above embodiments by the ordinary skilled in the art after reading the present specification all fall within the scope of the present application.

Claims

1. An adaptive spatial transmission method suitable for unidirectional channels, characterized in that, The system comprises a channel sending end and a channel receiving end; wherein: The channel sending end comprises: A channel state sensing unit, which senses a channel state and adjusts a spatial transmission mode correspondingly; A fountain code encoding unit, which encodes source information to obtain N encoded packets; A spread spectrum encoding unit, which respectively spreads spectrum encodes the N encoded packets according to the spatial transmission mode, to obtain spread spectrum encoded packets, wherein the spatial transmission mode comprises spatial diversity and spatial multiplexing, and wherein If the spatial transmission mode is spatial diversity, the spread spectrum encoding unit respectively spreads spectrum encodes the N encoded packets using pseudo code "sequence 0"; If the spatial transmission mode is spatial multiplexing, the spread spectrum encoding unit respectively spreads spectrum encodes the N encoded packets using pseudo code "sequence n" according to the number n of the transmitting antenna corresponding to the encoded packet; n is a positive integer greater than 1; A modulating and amplifying unit, which modulates and amplifies the spread spectrum encoded packets to send them as sending signals; A coupling unit, which couples the sending signals and analyzes the coupled signals to determine the current channel state and adjust the spatial transmission mode correspondingly; The channel receiving end comprises: A receiving unit, which receives receiving signals; A frequency down-conversion and demodulating unit, which frequency down-converts and demodulates the receiving signals; A decoding unit, which decodes the receiving signals according to the spatial diversity mode; A judging unit, which judges whether the decoding is successful, and if so, 2. The adaptive spatial transmission method for unidirectional channels of claim 1, wherein, Outputs first decoding information and performs fountain decoding; and if not, Performs packet decoding of the receiving signals according to the spatial multiplexing mode, and outputs several second decoding information; and 3. The adaptive spatial transmission method for unidirectional channels of claim 1, wherein, Performs fountain concatenated decoding of the several second decoding information. The decoding unit decodes the receiving signals according to the spatial diversity mode, comprising: Using "sequence 0" as a despread sequence number to despread the receiving signals.

4. The adaptive spatial transmission method for unidirectional channels of claim 1, wherein, The decoding unit performs packet decoding of the receiving signals according to the spatial multiplexing mode, comprising: Packing the receiving signals into receiving signal 1, receiving signal 2, …, receiving signal n according to receiving order; n is the number of transmitting antennas set by the channel sending end; Using "sequence 1" to "sequence n" as despread sequence numbers to despread the receiving signal 1, receiving signal 2, …, receiving signal n respectively. The decoding unit performs fountain concatenated decoding of the several second decoding information, comprising:

5. An adaptive spatial transmission system suitable for unidirectional channels, characterized in that, Finding all the rows with weight 1 in the encoding generator matrix G corresponding to the second decoding information; Adding all the rows with weight 1 in the encoding generator matrix G corresponding to the second decoding information; Performing fountain decoding according to the encoding generator matrix G to obtain source information corresponding to each second decoding information. The system comprises a channel sending end and a channel receiving end; wherein: The channel sending end comprises: A channel state sensing unit, which senses a channel state and adjusts a spatial transmission mode correspondingly; A fountain code encoding unit, which encodes source information to obtain N encoded packets; A spread spectrum encoding unit, which respectively spreads spectrum encodes the N encoded packets according to the spatial transmission mode, to obtain spread spectrum encoded packets, wherein the spatial transmission mode comprises spatial diversity and spatial multiplexing, and wherein If the spatial transmission mode is spatial diversity, the spread spectrum encoding unit respectively spreads spectrum encodes the N encoded packets using pseudo code "sequence 0"; If the spatial transmission mode is spatial multiplexing, the spread spectrum encoding unit respectively spreads spectrum encodes the N encoded packets using pseudo code "sequence n" according to the number n of the transmitting antenna corresponding to the encoded packet; n is a positive integer greater than 1; A modulating and amplifying unit, which modulates and amplifies the spread spectrum encoded packets to send them as sending signals; A coupling unit, which couples the sending signals and analyzes the coupled signals to determine the current channel state and adjust the spatial transmission mode correspondingly; The channel receiving end comprises: A receiving unit, which receives receiving signals; A frequency down-conversion and demodulating unit, which frequency down-converts and demodulates the receiving signals; A decoding unit, which decodes the receiving signals according to the spatial diversity mode; A judging unit, which judges whether the decoding is successful, and if so, Outputs first decoding information and performs fountain decoding; and if not, Performs packet decoding of the receiving signals according to the spatial multiplexing mode, and outputs several second decoding information; and Performs fountain concatenated decoding of the several second decoding information. The channel transmitting end comprises a fountain code encoding module, a spread spectrum encoding module, a modulation module, a coupler module and a transmitting antenna, the fountain code encoding module is connected with the spread spectrum encoding module, the spread spectrum encoding module is connected with the modulation module, the modulation module is connected with the coupler module, and the coupler module is connected with the transmitting antenna; the fountain code encoding module is used for fountain code encoding of source information to obtain N encoded packets; the spread spectrum encoding module is used for spread spectrum encoding of the N encoded packets respectively according to the spatial transmission mode to obtain spread spectrum encoded packets, the spread spectrum encoding module comprises a spatial diversity spread spectrum encoding unit and a spatial multiplexing spread spectrum encoding unit, wherein the spatial diversity spread spectrum encoding unit is used for spread spectrum encoding of the encoded packets by using pseudo code "sequence 0"; the spatial multiplexing spread spectrum encoding unit is used for spread spectrum encoding of the encoded packets by using pseudo code "sequence n" according to the number n of the transmitting antenna corresponding to the encoded packet; n is a positive integer greater than 1; the modulation module is used for modulation and amplification of the spread spectrum encoded packets as transmitting signals; the coupler module is used for coupling part of the transmitting signals, analyzing the coupled signals, determining the current channel state and adjusting the spatial transmission mode correspondingly; and the transmitting antenna is used for transmitting the transmitting signals to the channel receiving end. The channel receiving end comprises a receiving antenna, a frequency conversion and demodulation module, a spatial diversity decoding module, a spatial multiplexing decoding module and a fountain code decoding module, the receiving antenna is connected with the frequency conversion and demodulation module, the frequency conversion and demodulation module is connected with the spatial diversity decoding module and the spatial multiplexing decoding module, and the spatial diversity decoding module and the spatial multiplexing decoding module are connected with the fountain code decoding module; the receiving antenna is used for collecting receiving signals; the frequency conversion and demodulation module is used for frequency conversion and demodulation of the receiving signals; the spatial diversity decoding module is used for decoding of the receiving signals in the spatial diversity mode and output of first decoding information; the spatial multiplexing decoding module is used for packet decoding of the receiving signals in the spatial multiplexing mode and output of a plurality of second decoding information; and the fountain code decoding module is used for fountain code decoding of the first decoding information and fountain code cascade decoding of the plurality of second decoding information.

6. The adaptive spatial transmission system suitable for one-way channel according to claim 5, wherein the spatial diversity decoding module is used for despreading of the receiving signals by using "sequence 0" as a despreading sequence number; the spatial multiplexing decoding module is used for packetizing the receiving signals into receiving signal 1, receiving signal 2, …, receiving signal n according to receiving order; n is the number of transmitting antennas provided by the channel transmitting end; and the receiving signal 1, the receiving signal 2, …, the receiving signal n are respectively despreaded by using "sequence 1" to "sequence n" as despreading sequence numbers. ​

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