An integrated flexible communication system compatible with fdd and tdd

Abstract

The application discloses an integrated flexible communication system compatible with FDD and TDD, which comprises a radio frequency transmitting unit, a radio frequency receiving unit, a continuous signal processing unit, a special signal processing unit, a burst signal processing unit and a state machine control unit. The application recombines the physical layer, the coding and synchronization sublayer, the MAC sublayer, the frame sublayer, the I / O sublayer and the network layer in the FDD communication system and the TDD communication system according to the function implementation mechanism, breaks the traditional layered architecture, fuses the common modules dispersed in each sublayer according to the large data processing mechanism and the scheduling control processing mechanism, trims the control and signal processing units exclusive to each sublayer, greatly reduces the processing and scheduling overhead in the traditional layered implementation mode, and reduces the hardware implementation complexity of each function mechanism, thereby most supporting the stringent requirement of the deep space exploration task on product miniaturization.

Description

Technical Field

[0001] This invention relates to an integrated and flexible communication system compatible with both FDD and TDD, belonging to the field of near-space communication networking for deep space exploration. Background Technology

[0002] In my country's lunar exploration program, a high-throughput communication network is involved among multiple nodes in the near-space region of the moon. Its main functions include: ① achieving efficient point-to-point communication based on CCSDS Proximity-1 full-duplex mode within the near-space region; ② establishing a flexible network among multiple nodes on the lunar surface. The CCSDS Proximity-1 protocol layer comprises two main parts: the data link layer and the physical layer. The data link layer is further divided into five functionally independent sublayers: the Frame Sub-layer, the Media Access Control Sub-layer, the Coding and Synchronization Sub-layer, the Data Services Sub-layer, and the Input / Output Sub-layer. The flexible network among multiple nodes on the lunar surface uses a TDD communication system, comprising the physical layer, data link layer, and network layer. Due to the extremely stringent requirements of my country's lunar exploration program for product miniaturization and low power consumption, as well as the need to support the CCSDSProximity-1 system (two types of FDD nodes) and flexible lunar surface networking based on TDD, the demand for processing resources is enormous. Therefore, the traditional system protocol implementation method (FPGA+CPU) can no longer meet the requirements of the lunar exploration program. Summary of the Invention

[0003] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and propose an integrated flexible communication system that is compatible with both FDD and TDD.

[0004] The objective of this invention is achieved through the following technical solutions:

[0005] An integrated flexible communication system compatible with FDD and TDD includes: transceiver A and transceiver B. Transceiver A includes: radio frequency transmitting unit A, radio frequency receiving unit A, continuous signal processing unit A, special signal processing unit A, burst signal processing unit A, and state machine control unit A; transceiver B includes: radio frequency transmitting unit B, radio frequency receiving unit B, continuous signal processing unit B, special signal processing unit B, burst signal processing unit B, and state machine control unit B.

[0006] When transceiver A's state machine control unit A receives an external control signal to activate FDD mode, it first resets special signal processing unit A, putting it into low-power mode. Next, it configures RF transmitting unit A and RF receiving unit A as a call channel and generates the data field of a V3 transmission frame according to the forward / backward rate, forward / backward coding method, and service channel number specified in the control signal. This data field is then sent to burst signal processing unit A. Upon successful reception, burst signal processing unit A counts the input data, extracts the length of the V3 transmission frame data field, fills it into the frame length and frame sequence number areas in the frame header, and generates a proximity space link transmission unit, which is then sent to RF transmitting unit A. Upon receiving the proximity space link transmission unit, RF transmitting unit A performs convolutional coding on it, generating a Hail P-Frame at a rate of 1 kbps. This frame is then modulated onto an RF signal and sent to RF receiving unit B of transceiver B.

[0007] In transceiver B, when its state machine control unit B receives an external control signal to activate FDD mode, it first resets the special signal processing unit B, putting it into low-power mode. Then, it configures the radio frequency transmitting unit B and the radio frequency receiving unit B as call channels, waiting for transceiver A to initiate a call. When the radio frequency receiving unit B receives the Hail P-Frame, it decodes it and sends the obtained near-space link transmission unit to the burst signal processing unit B. The burst signal processing unit B first determines the position of the ASM header in the near-space link transmission unit, then reads the frame length information from the frame header of the V3 transmission frame, thereby extracting the V3 transmission frame for CRC verification. After successful verification, it parses the forward / backward rate, forward / backward coding method, and service channel number from the data field of the V3 transmission frame and sends them to the state machine control unit B. After receiving the forward / backward rate, forward / backward coding scheme, and service channel number, state machine control unit B configures the backward rate, backward coding scheme, and service channel number to RF transmitting unit B, and configures the forward rate, forward coding scheme, and service channel number to RF receiving unit B. Then, it sends the split external valid frame to continuous signal processing unit B. Continuous signal processing unit B counts the input data blocks, extracts their length, fills them into the frame length area and frame sequence number area in the frame header, and generates a proximity space link transmission unit, which is then sent to RF transmitting unit B. Upon receiving the proximity space link transmission unit, RF transmitting unit B generates a U-Frame according to the configured coding scheme, rate, and service channel number, modulates it onto an RF signal, and sends it to RF receiving unit A of transceiver A.

[0008] In transceiver A, after the radio frequency (RF) transmitting unit A sends the Hail P-Frame, the state machine control unit A configures the back-fly rate, back-fly coding scheme, and service channel number from the external control signals to the RF receiving unit A, and configures the forward rate, forward coding scheme, and service channel number to the RF transmitting unit A. Then, it sends the split external valid frame to the continuous signal processing unit A. The continuous signal processing unit A counts the input data blocks, extracts their length, fills them into the frame length area and frame sequence number area in the frame header, and generates a proximity space link transmission unit, which is then sent to the RF transmitting unit A. Upon receiving the proximity space link transmission unit, the RF transmitting unit A generates a U-Frame according to the configured coding scheme, rate, and service channel number, modulates it onto an RF signal, and sends it to the RF receiving unit B of transceiver B. At this point, the FDD communication system process ends.

[0009] When transceiver A's state machine control unit A receives an external control signal to activate TDD mode, it first resets the continuous signal processing unit A, putting it into low-power mode. Then, it configures the back-fly rate, back-fly coding scheme, and service channel number from the external control signal to the RF receiving unit A, and configures the forward rate, forward coding scheme, and service channel number to the RF transmitting unit A. In addition, it configures the forward transmission duration T... 前向 The forward frame time stamp is sent to radio frequency transmitter unit A, and the return transmission duration T is sent. 返向 The return frame time stamp is sent to RF receiving unit A. Finally, the external valid frame, forward rate, and forward transmission duration T are sent. 前向 The data is sent to Special Signal Processing Unit A. Upon successful reception, Special Signal Processing Unit A uses a TDD data interception algorithm to split the external valid frame and sends the split external valid frame to Burst Signal Processing Unit A before the next forward frame time stamp. Burst Signal Processing Unit A counts the input split external valid frames, extracts their length, fills the frame length and frame sequence number areas in the frame header, and generates a Near Space Link Transmission Unit, which is then sent to Radio Frequency Transmitting Unit A. Upon receiving the Near Space Link Transmission Unit, Radio Frequency Transmitting Unit A generates a U-Frame according to the configured encoding method, rate, and service channel number. After the forward frame time stamp, it modulates the U-Frame onto an radio frequency signal and sends it to Radio Frequency Receiving Unit B of Transceiver B.

[0010] In transceiver B, when its state machine control unit B receives an external control signal to activate TDD mode, it first resets the continuous signal processing unit B, putting it into a low-power mode. Then, it configures the back-flying rate, back-flying coding method, and service channel number from the external control signal to the radio frequency transmitting unit B, and configures the forward-flying rate, forward-flying coding method, and service channel number to the radio frequency receiving unit B. In addition, it configures the forward transmission duration T... 前向The forward frame time stamp is sent to the radio frequency receiving unit B, and the return transmission duration T is sent. 返向 The return frame time stamp is sent to RF transmitting unit B. Finally, the external valid frame, return rate, and return transmission duration T are sent. 返向 The data is sent to Special Signal Processing Unit B. Upon successful reception, Special Signal Processing Unit B uses the TDD data interception algorithm to split the external valid frame and sends the split external valid frame to Burst Signal Processing Unit B before the next return frame time stamp. Burst Signal Processing Unit B counts the input split external valid frames, extracts their length, fills the frame length and frame sequence number areas in the frame header, and generates a Near Space Link Transmission Unit, which is then sent to Radio Frequency Transmitting Unit B. Upon receiving the Near Space Link Transmission Unit, Radio Frequency Transmitting Unit B generates a U-Frame according to the configured encoding method, rate, and service channel number. After the return frame time stamp, it modulates the U-Frame onto an radio frequency signal and sends it to Radio Frequency Receiving Unit A of Transceiver A. At this point, the TDD communication system process ends.

[0011] Preferably, the calling channel is the Hailing Channel specified in the CCSDS Proximity-1 protocol, namely channel 1, 1kbps and convolutional encoding and decoding.

[0012] Preferably, the V3 transfer frame, specifically the Version-3 Transfer Frame, consists of a frame header and a data field, wherein the frame header is 5 bytes and the data field is 1 to 2043 bytes.

[0013] Preferably, the Proximity Link Transmission Unit consists of a 3-byte ASM header, a V3 transmission frame, and a 4-byte CRC checksum.

[0014] Preferably, the Hail P-Frame is a control signal transmitted in the form of a V3 transmission frame, used to inform the other party of the frequency point, forward and backward rate and encoding method of the service channel of the transceiver.

[0015] Preferably, the external valid frame after splitting is specifically split into a form with a maximum length of no more than 2043 bytes. Generally, the length of the external valid frame after splitting is an integer power of 2.

[0016] Preferably, the U-Frame is a user data signal transmitted in the form of a V3 transmission frame.

[0017] Preferably, the forward frame timestamp is the starting point of the forward communication time.

[0018] Preferably, the return frame timestamp is the starting point of the return communication time.

[0019] Preferably, the TDD data interception algorithm is specifically calculated as forward / backward rate × forward / backward transmission duration × (1-η) / 8, rounded down to the power of 2, where η is the time protection interval.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] (1) By integrating the continuous signal processing functions of each sub-layer in the FDD communication system and the TDD communication system into the continuous signal processing unit, the slice and RAM resources in the FPGA (Field-Programmable Gate Array) are greatly saved.

[0022] (2) By integrating the burst signal processing functions of each sub-layer in the FDD communication system and the TDD communication system into the burst signal processing unit, the Slice and DSP resources in the FPGA (Field-Programmable Gate Array) are greatly saved.

[0023] (3) The state machine control unit integrates the control functions and protocol processing functions of each sub-layer in the FDD communication system and the TDD communication system, and switches flexibly in the form of a state machine, thus avoiding the use of the CPU.

[0024] (4) The state machine control unit merges resources such as Block RAM according to the time-sharing principle, which greatly saves RAM resources in the FPGA.

[0025] (5) This invention can be applied to deep space exploration, represented by the moon, and embodies the design concept of optimal products and optimal resources in deep space exploration missions. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the system of the present invention.

[0027] Figure 2 This is a block diagram of the PLTU format and its components.

[0028] Figure 3 This is a block diagram of the frame header. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0030] An integrated flexible communication system compatible with FDD and TDD is proposed. This system reorganizes the physical layer, coding and synchronization sublayer, MAC sublayer, frame sublayer, I / O sublayer, and network layer of the CCSDS Proximity-1 and lunar multi-node flexible networking system according to their respective functional implementation mechanisms. This breaks away from the traditional layered architecture and integrates the common modules scattered in each sublayer according to the big data processing mechanism and scheduling and control processing mechanism. It also eliminates the dedicated control and signal processing units of each sublayer, significantly reducing the processing and scheduling overhead in the traditional layered implementation method and reducing the hardware implementation complexity of each functional mechanism. Compared with the traditional implementation method of FDD and TDD communication systems, it significantly reduces resources and reflects the design concept of product optimization and resource optimization in deep space exploration missions.

[0031] like Figure 1 As shown, an integrated flexible communication system compatible with FDD and TDD includes: transceiver A and transceiver B. Transceiver A includes: radio frequency transmitting unit A, radio frequency receiving unit A, continuous signal processing unit A, special signal processing unit A, burst signal processing unit A, and state machine control unit A; transceiver B includes: radio frequency transmitting unit B, radio frequency receiving unit B, continuous signal processing unit B, special signal processing unit B, burst signal processing unit B, and state machine control unit B.

[0032] When transceiver A's state machine control unit A receives an external control signal to activate FDD mode, it first resets special signal processing unit A, putting it in low-power mode. Then, it configures RF transmitting unit A and RF receiving unit A as a call channel, specifically the Hailing Channel specified in the CCSDS Proximity-1 protocol, namely channel 1 (forward frequency 435.6MHz, backward frequency 404.4MHz), 1kbps, and convolutional encoding / decoding. Subsequently, it generates the data field of a V3 transmission frame according to the forward / backward rates, forward / backward coding scheme, and service channel number specified in the control signal, and sends it to burst signal processing unit A. The V3 transmission frame is as follows: Figure 2 As shown, its full name is Version-3 Transfer Frame, which consists of a frame header and a data field. The frame header is 5 bytes and the data field is 1 to 2043 bytes.

[0033] After successfully receiving the data field of the V3 transmission frame, the burst signal processing unit A counts the input data, extracts its length, fills it into the frame length area and frame sequence number area in the frame header, and generates a near-space link transmission unit, which is then sent to the radio frequency transmission unit A. The near-space link transmission unit is as follows: Figure 2As shown, its full name is Proximity Link Transmission Unit, which consists of a 3-byte ASM header, a V3 transport frame, and a 4-byte CRC checksum. The block diagram of the frame header is shown below. Figure 3 As shown, the frame length area contains 11 bits, and the frame sequence number area contains 8 bits.

[0034] After receiving the near-space link transmission unit, radio frequency transmitting unit A performs convolutional coding on it to generate a Hail P-Frame at a rate of 1kbps. This frame is then modulated onto a radio frequency signal and transmitted to radio frequency receiving unit B of transceiver B. The Hail P-Frame is specifically a control signal transmitted in the form of a V3 transmission frame, used to inform transceiver B of the frequency point, forward and backward rates, and coding method of the service channel.

[0035] In transceiver B, when its state machine control unit B receives an external control signal to activate FDD mode, it first resets the special signal processing unit B, putting it into low-power mode. Then, it configures the radio frequency transmitting unit B and the radio frequency receiving unit B as call channels, waiting for transceiver A to initiate a call. When the radio frequency receiving unit B receives the Hail P-Frame, it decodes it and sends the obtained near-space link transmission unit to the burst signal processing unit B. The burst signal processing unit B first determines the position of the ASM header in the near-space link transmission unit, then reads the frame length information from the frame header of the V3 transmission frame, thereby extracting the V3 transmission frame for CRC verification. After successful verification, it parses the forward / backward rate, forward / backward coding method, and service channel number from the data field of the V3 transmission frame and sends them to the state machine control unit B. After receiving the forward / backward rate, forward / backward coding scheme, and service channel number, state machine control unit B configures the backward rate, backward coding scheme, and service channel number to radio frequency transmission unit B, and configures the forward rate, forward coding scheme, and service channel number to radio frequency receiving unit B. Then, it sends the split external valid frame to continuous signal processing unit B, such as... Figure 2 As shown, the maximum length of the split external effective frame does not exceed 2043 bytes. In order to facilitate digital signal processing and save resources, the length of the split external effective frame is generally an integer power of 2, such as 1024, 512, 256, etc.

[0036] After receiving the split external valid frames, continuous signal processing unit B counts them, extracts their length, fills the frame length area and frame sequence number area in the frame header, and generates a proximity space link transmission unit, which is then sent to radio frequency transmission unit B. Upon receiving the proximity space link transmission unit, radio frequency transmission unit B generates a U-Frame according to the configured encoding method, rate, and service channel number, modulates it onto a radio frequency signal, and sends it to radio frequency receiving unit A of transceiver A. According to the CCSDS protocol, the U-Frame is specifically a user data signal transmitted in V3 transmission frame format.

[0037] In transceiver A, after the radio frequency (RF) transmitting unit A sends the Hail P-Frame, the state machine control unit A configures the back-fly rate, back-fly coding scheme, and service channel number from the external control signals to the RF receiving unit A, and configures the forward rate, forward coding scheme, and service channel number to the RF transmitting unit A. Then, it sends the split external valid frame to the continuous signal processing unit A. The continuous signal processing unit A counts the input data blocks, extracts their length, fills them into the frame length area and frame sequence number area in the frame header, and generates a proximity space link transmission unit, which is then sent to the RF transmitting unit A. Upon receiving the proximity space link transmission unit, the RF transmitting unit A generates a U-Frame according to the configured coding scheme, rate, and service channel number, modulates it onto an RF signal, and sends it to the RF receiving unit B of transceiver B. At this point, the FDD communication system process ends.

[0038] When transceiver A's state machine control unit A receives an external control signal to activate TDD mode, it first resets the continuous signal processing unit A, putting it into low-power mode. Then, it configures the back-fly rate, back-fly coding scheme, and service channel number from the external control signal to the RF receiving unit A, and configures the forward rate, forward coding scheme, and service channel number to the RF transmitting unit A. In addition, it configures the forward transmission duration T... 前向 The forward frame time stamp is sent to radio frequency transmitter unit A, and the return transmission duration T is sent. 返向 The forward and return frame time stamps are sent to the radio frequency receiving unit A. Specifically, the forward and return frame time stamps are the start and end times of the forward and return communications, accurate to the microsecond level.

[0039] Finally, state machine control unit A will input the external valid frames, forward rate, and forward transmission duration T. 前向The data is sent to Special Signal Processing Unit A. Upon successful reception, Special Signal Processing Unit A uses a TDD data interception algorithm to split the external valid frame. Specifically, the split is calculated as forward rate × forward transmission duration × (1-η) / 8, rounded down to the power of 2, where η is the time guard interval, typically not less than 5%. The split external valid frame is then sent to Burst Signal Processing Unit A before the next forward frame time stamp. Burst Signal Processing Unit A counts the input split external valid frames, extracts their length, fills it into the frame length and frame sequence number areas in the frame header, and generates a Near Space Link Transmission Unit, which is then sent to Radio Frequency Transmitting Unit A. Upon receiving the Near Space Link Transmission Unit, Radio Frequency Transmitting Unit A generates a U-Frame according to the configured encoding method, rate, and service channel number. After the forward frame time stamp, it is modulated into an radio frequency signal and sent to Radio Frequency Receiving Unit B of Transceiver B.

[0040] In transceiver B, when its state machine control unit B receives an external control signal to activate TDD mode, it first resets the continuous signal processing unit B, putting it into a low-power mode. Then, it configures the back-flying rate, back-flying coding method, and service channel number from the external control signal to the radio frequency transmitting unit B, and configures the forward-flying rate, forward-flying coding method, and service channel number to the radio frequency receiving unit B. In addition, it configures the forward transmission duration T... 前向 The forward frame time stamp is sent to the radio frequency receiving unit B, and the return transmission duration is sent to the transmission duration T. 返向 The data is sent to Special Signal Processing Unit B. Upon successful reception, Special Signal Processing Unit B uses the TDD data interception algorithm to split the external valid frame. Specifically, the split frame is calculated as return rate × return transmission duration × (1-η) / 8, rounded down to the power of 2, where η is the time guard interval, typically not less than 5%. The split external valid frame is then sent to Burst Signal Processing Unit B before the next return frame time stamp. Burst Signal Processing Unit B counts the input split external valid frames, extracts their length, fills it into the frame length and frame sequence number areas in the frame header, and generates a proximity space link transmission unit, which is then sent to Radio Frequency Transmitting Unit B. Upon receiving the proximity space link transmission unit, Radio Frequency Transmitting Unit B generates a U-Frame according to the configured encoding method, rate, and service channel number. After the return frame time stamp, it is modulated into an radio frequency signal and sent to Radio Frequency Receiving Unit A of Transceiver A. This concludes the TDD communication system process.

[0041] This invention has been implemented and verified on the UHF transceiver of a detector telemetry and data transmission subsystem and the UHF transceiver of a relay satellite relay communication subsystem. It realizes FDD and TDD communication systems using only one K7 series FPGA. The product functions and performance meet the overall requirements, and the weight and power consumption of the product are significantly reduced.

[0042] This invention is low in complexity and flexible in implementation, and can be widely applied in deep space exploration, represented by the Moon. It provides strong technical support for the establishment of a lunar near-space communication system under conditions where resources such as power and weight are limited, and has great technical and economic value.

[0043] The contents not described in detail in this specification are common knowledge to those skilled in the art.

[0044] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. An integrated flexible communication system compatible with both FDD and TDD, characterized in that, include: Transceiver A and transceiver B. Transceiver A includes: radio frequency transmitting unit A, radio frequency receiving unit A, continuous signal processing unit A, special signal processing unit A, burst signal processing unit A, and state machine control unit A; transceiver B includes: radio frequency transmitting unit B, radio frequency receiving unit B, continuous signal processing unit B, special signal processing unit B, burst signal processing unit B, and state machine control unit B. The FDD communication system process includes: When the state machine control unit A receives the external control signal to start the FDD mode, it first resets the special signal processing unit A to put it in low-power mode. Then, it configures the radio frequency transmitting unit A and the radio frequency receiving unit A as a call channel, and generates the data field of the V3 transmission frame according to the forward and backward rate, forward and backward coding method and service channel number specified in the control signal, and sends it to the burst signal processing unit A. After the burst signal processing unit A successfully receives the data, it counts the input data and extracts the length of the V3 transmission frame data field, fills it into the frame length area and frame sequence number area in the frame header, and generates the adjacent space link transmission unit, which is then sent to the radio frequency transmitting unit A. After receiving the adjacent space link transmission unit, the radio frequency transmitting unit A performs convolutional coding on it to generate a Hail P-Frame, modulates it into a radio frequency signal and sends it to the radio frequency receiving unit B of the transceiver B. In transceiver B, when the state machine control unit B receives an external control signal to activate FDD mode, it first resets the special signal processing unit B to a low-power mode. Then, it configures the radio frequency transmitting unit B and the radio frequency receiving unit B as call channels, waiting for transceiver A to initiate a call. When the radio frequency receiving unit B receives the Hail P-Frame, it decodes it and sends the obtained near-space link transmission unit to the burst signal processing unit B. The burst signal processing unit B first determines the position of the ASM header in the near-space link transmission unit, then reads the frame length information from the frame header of the V3 transmission frame, extracts the V3 transmission frame for CRC verification, and after successful verification, parses the forward / backward rate, forward / backward coding scheme, and service channel number from the data field of the V3 transmission frame, and sends it to the state machine control unit B. Upon receiving the forward / backward rate, forward / backward coding scheme, and service channel number, the state machine control unit B... The forward rate, forward coding scheme, and service channel number are configured for the radio frequency transmitting unit B. Then, the split external valid frame is sent to the continuous signal processing unit B. The continuous signal processing unit B counts the input data blocks and extracts their length, fills them into the frame length area and frame sequence number area in the frame header, and generates an adjacent space link transmission unit, which is then sent to the radio frequency transmitting unit B. After receiving the adjacent space link transmission unit, the radio frequency transmitting unit B generates a U-Frame according to the configured coding scheme, rate, and service channel number, modulates it onto a radio frequency signal, and sends it to the radio frequency receiving unit A of the transceiver A. In transceiver A, after the radio frequency transmitting unit A sends out the Hail P-Frame, the state machine control unit A configures the back-fly rate, back-fly coding method, and service channel number from the external control signal to the radio frequency receiving unit A, and configures the forward rate, forward coding method, and service channel number to the radio frequency transmitting unit A. Then, it sends the split external valid frame to the continuous signal processing unit A. The continuous signal processing unit A counts the input data blocks and extracts their length, fills them into the frame length area and frame sequence number area in the frame header, and generates a proximity space link transmission unit, which is then sent to the radio frequency transmitting unit A. After receiving the proximity space link transmission unit, the radio frequency transmitting unit A generates a U-Frame according to the configured coding method, rate, and service channel number, modulates it onto a radio frequency signal, and sends it to the radio frequency receiving unit B of transceiver B. The TDD communication system process includes: When state machine control unit A receives an external control signal to initiate TDD mode, it first resets continuous signal processing unit A, putting it into low-power mode. Then, it configures the back-row rate, back-row coding method, and service channel number from the external control signal to RF receiving unit A, and configures the forward rate, forward coding method, and service channel number to RF transmitting unit A. In addition, it configures the forward transmission duration... The forward frame time stamp is sent to radio frequency transmitter unit A, and the return transmission duration is sent. The return frame time stamp is sent to RF receiving unit A; finally, the external valid frame, forward rate, and forward transmission duration are sent. The data is sent to special signal processing unit A. After successful reception, special signal processing unit A uses the TDD data interception algorithm to split the external valid frame and sends the split external valid frame to burst signal processing unit A before the next forward frame time stamp. Burst signal processing unit A counts the input split external valid frames and extracts their length, filling it into the frame length area and frame sequence number area in the frame header, and generates a near space link transmission unit, which is then sent to radio frequency transmission unit A. After receiving the near space link transmission unit, radio frequency transmission unit A generates a U-Frame according to the configured encoding method, rate and service channel number, modulates it into a radio frequency signal after the forward frame time stamp, and sends it to radio frequency receiving unit B of transceiver B. In transceiver B, when its state machine control unit B receives an external control signal to activate TDD mode, it first resets the continuous signal processing unit B, putting it into low-power mode. Then, it configures the back-fly rate, back-fly coding scheme, and service channel number from the external control signal to the radio frequency transmitting unit B, and configures the forward rate, forward coding scheme, and service channel number to the radio frequency receiving unit B. In addition, it configures the forward transmission duration... The forward frame time stamp is sent to the radio frequency receiving unit B, and the return transmission duration is sent. The return frame time stamp is sent to RF transmitting unit B; finally, the external valid frame, return rate, and return transmission duration are sent. The data is sent to Special Signal Processing Unit B. After successful reception, Special Signal Processing Unit B uses the TDD data interception algorithm to split the external valid frame and sends the split external valid frame to Burst Signal Processing Unit B before the next return frame time stamp. Burst Signal Processing Unit B counts the input split external valid frames and extracts their length, filling it into the frame length area and frame sequence number area in the frame header, and generates a Near Space Link Transmission Unit, which is then sent to Radio Frequency Transmitting Unit B. After receiving the Near Space Link Transmission Unit, Radio Frequency Transmitting Unit B generates a U-Frame according to the configured encoding method, rate, and service channel number, and modulates it into a radio frequency signal after the return frame time stamp before sending it to Radio Frequency Receiving Unit A of Transceiver A.

2. The integrated flexible communication system according to claim 1, characterized in that, The call channel is specifically the Hailing Channel as defined in the CCSDSProximity-1 protocol.

3. The integrated flexible communication system according to claim 1, characterized in that, The V3 transfer frame, specifically the Version-3 Transfer Frame, consists of a frame header and a data field. The frame header is 5 bytes long, and the data field is 1 to 2043 bytes long.

4. The integrated flexible communication system according to claim 1, characterized in that, The Proximity Link Transmission Unit (PRT) consists of a 3-byte ASM header, a V3 transmission frame, and a 4-byte CRC checksum.

5. The integrated flexible communication system according to claim 1, characterized in that, Hail P-Frame is a control signal transmitted in the form of a V3 transmission frame, used to inform the other party of the frequency point, forward and backward rates, and encoding method of the service channel of the transceiver.

6. The integrated flexible communication system according to claim 1, characterized in that, The split external valid frame is specifically split into segments with a maximum length of no more than 2043 bytes, and the length of the split external valid frame is an integer power of 2.

7. The integrated flexible communication system according to claim 1, characterized in that, U-Frame refers specifically to user data signals transmitted in the form of V3 transmission frames.

8. The integrated flexible communication system according to claim 1, characterized in that, Forward frame timestamp, specifically the starting point of the forward communication time.

9. The integrated flexible communication system according to claim 1, characterized in that, The return frame timestamp is specifically the starting point of the return communication time.

10. The integrated flexible communication system according to claim 1, characterized in that, The TDD data interception algorithm is specifically calculated as: forward / backward rate × forward / backward transmission duration × (1-η) / 8, rounded down to the power of 2, where η is the time protection interval.

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