CN101136722B - Data transmitting method and transmitting equipment suitable for high speed mobile terminal - Google Patents

Abstract

Dividing up original data packet (DP) into multiple small data packets (SDPs) with same or different lengths in order to transmit info in different priority levels, the sending end adds serial number and cyclic redundancy check (CRC) code for each SDP, and carries out permutation and combination for processed SDPs according to appointed order. Modulating the received signal to obtain DP, the receiving end carried out error corrected decoding DP so as to obtain decoded DP. Extracting SDP with pointed length from pointed position of the decoded DP, the method carries out CRC for each SDP. The invention can reduce average number of retransmission repeated request automatically, raise effective throughput, shorten transmission delay, and reduce ratio of losing packets. In each time of transmission repeated request automatically, the invention uses different sequence to permute, combine, encode, modulate, and send SDPs. Retransmission obtains diversity gain in time or frequency.

Description

A data transmission method and transmission equipment suitable for high-speed mobile terminals

technical field

The invention relates to a data sending method and transmission equipment suitable for high-speed mobile terminals, and relates to the field of data transmission in communication systems.

Background technique

Using a wireless channel to send data packets, when the duration of a frame of data packets is much shorter than the coherence time of the channel, the channel fading experienced by a frame of data packets is basically unchanged. When the mobile speed of the terminal gradually increases, the coherence time of the channel is shortened, and the duration of a frame of data packets cannot meet the condition of being much shorter than the channel coherence time, a frame of data packets experiences different channel fading, which leads to channel estimation/equalization. As the difficulty increases, the probability of packet errors introduced by channel estimation/channel equalization errors increases.

Currently, there are two main methods of data packet transmission:

1) Method 1, as shown in Figure 1, inserts a pilot at the beginning of the data packet for channel estimation and channel equalization of a frame of data packets;

The advantages of this method are: the pilot overhead is small, the channel estimation method is simple, and the processing time is short;

The disadvantage of this method is that it is only applicable to the case where the mobile speed of the terminal is relatively low, the length of the data packet is relatively short, and the duration of a frame of data packet is much shorter than the channel coherence time. Using this method, when the data packet length is long or the terminal moves at a high speed, the probability of data packet error (BLER, Block Error Rate) will increase significantly.

2) Method 2, as shown in Figure 2, inserts pilots at multiple specific positions of the data packet, for channel estimation and channel equalization of a frame of data packets;

The advantage of this method is that it can be applied to the situation where the terminal moves at a high speed and the length of the data packet is long, that is, a frame of data packets experiences fading of different channels. The premise is that the coherence time of the channel is much longer than the time interval of inserting the pilot.

The disadvantage of this method is: with the shortening of channel coherence time, the aggravation of channel variation needs to insert pilots at shorter time intervals. The overhead of the pilot frequency is large, the method of channel estimation/equalization is complicated, and the processing time is long.

No matter which method is adopted, the aggravation of the channel variation will lead to an increase of channel estimation/channel equalization error, thus leading to an increase of BLER. In other words, as the mobile speed of the terminal increases, the BLER also increases.

In order to reduce the probability of data packet loss (BLLR, Block LostRate) caused by data packet transmission errors, a common approach is to introduce an error retransmission mechanism, usually using hybrid automatic repeat request (HARQ, hybrid automatic retransmission request). HARQ is a link adaptive technology that combines forward error correction coding (FEC, Forward Error Correction) and automatic repeat request (ARQ, automatic retransmission request). Data packets contain parity bits for error correction and error detection. The receiver first performs error correction decoding on the data packet, such as convolutional decoding and Turbo decoding, and then performs a cyclic redundancy check (CRC, Cyclic Redundancy Check) on the output of the error correction decoding. If the CRC check is passed, then Indicates that the data packet is received correctly, and the receiving end sends a positive acknowledgment (ACK, acknowledgment). If the CRC check fails, it indicates that the transmission error exceeds the error correction capability of FEC, and the data packet cannot be received correctly, and the receiving end sends a negative acknowledgment (NAK) , non-acknowledgment). The sender resends the data packet or sends a new data packet according to the response information. The advantage of this method is that it can reduce the probability of packet loss and has a certain degree of channel adaptive capability. When the channel condition is good, the BLER is low, the average number of retransmissions is small, the effective data transmission rate is high, and the actual encoding rate is high. When the channel condition becomes worse, the BLER increases, the average number of retransmissions increases, the effective data transmission rate decreases, and the actual encoding rate decreases. That is, the transmission rate and encoding rate are adjusted according to channel conditions.

The disadvantage of this method is that a response mechanism needs to be introduced in the reverse channel, which increases the complexity of the system and occupies a certain system bandwidth.

Contents of the invention

In order to make up for the deficiencies of the prior art, the present invention proposes a data transmission method and transmission equipment suitable for high-speed mobile terminals for data transmission in a wireless communication system.

To achieve the above purpose, a data transmission method suitable for high-speed mobile terminals includes a data sending method and a data receiving method.

A data sending method suitable for high-speed mobile terminals, the sending end includes the following steps:

The sender divides the original data packet into multiple small data packets;

The sender adds a packet sequence number to each data packet;

The sender adds cyclic redundancy check bits to each data packet;

The sender arranges the small data packets in a specific order and combines them into one data packet;

The sending end performs error correction coding on the generated data packet;

The sending end modulates and sends the encoded data packets.

A data receiving method suitable for high-speed mobile terminals, the receiving end includes the following steps:

The receiving end demodulates the received signal to obtain the data packet;

The receiving end performs error correction and decoding on the data packet;

The receiving end extracts small data packets from the decoded data packets in a specific order and length;

The receiving end performs a cyclic redundancy check on each small data packet;

When receiving a new data packet, if any small data packet fails the cyclic redundancy check, the receiving end sends a negative response;

When receiving retransmitted data packets, combined with the results of the previous several transmission cyclic redundancy checks, if there are still small data packets that are not received correctly, the sender sends a negative response message;

When receiving retransmitted data packets, combined with the results of the previous several transmission cyclic redundancy checks, if all small data packets have been received correctly, the receiving end sends a positive response message;

The receiving end sorts and combines the correctly received small data packets according to the sequence numbers of the packets.

A data transmission device suitable for high-speed mobile terminals, including a sending device and a receiving device; the sending device includes:

Divide the data packet into small data packets according to the specified length, and the length of these small data packets can be the same or different data packet splitters;

A packet sequence number generator that generates a unique packet sequence number for each small data packet;

Generate a cyclic redundancy check code of a specified length for each small data packet, the length of the small data packet cyclic redundancy check code can be the same or different cyclic redundancy check code generator;

Permutation and combination of small data packets with added packet sequence numbers and cyclic redundancy check codes in a specified order, data packet permutation that can permutate and combine small data packets in the same or different order for each transmission of an automatic repeat request combination device;

an encoder for error-correcting encoding of the data packets;

A modulator that modulates the encoded data packet onto the carrier;

Select a sending device for sending a new data packet or resending a data packet according to the content of the received response information;

Receiving equipment includes:

A receiving device for receiving space wireless signals of a specific frequency;

A demodulator that demodulates the received signal to obtain the data packet;

Perform a decoding operation on the data packet, and output a decoder for the decoded data packet;

A data packet extraction device for extracting small data packets from the decoded data packets according to the position and length agreed with the sending end;

a cyclic redundancy checker for performing a cyclic redundancy check on the extracted packet;

Sorting and combining the small data packets according to the packet sequence numbers, and outputting a data packet sorting and combining device for receiving the data packets;

A response message generator that synthesizes the cyclic redundancy check results of all small data packets to generate a response message.

The block diagram of the sending device is shown in Figure 7. The data packet splitter outputs the divided small data packets to the packet sequence number generator; the packet sequence number generator outputs the small data packets with the packet sequence number added to the CRC generator; the CRC generator outputs the CRC checksum The small data packet for code checking is sent to the data packet arranging device; the data packet arranging device outputs the sorted and combined data packet to the encoder; the encoder outputs the encoded data packet to the modulator; the modulator outputs the modulated signal to the sending device; The sending device sends out the modulated signal.

The block diagram of the receiving device is shown in Figure 8. The receiving device outputs signals to the demodulator; the demodulator outputs data packets to the decoder; the decoder outputs decoded data packets to the data packet extraction device; the data packet extraction device outputs small data Packet to the cyclic redundancy checker; the cyclic redundancy checker outputs correctly received small data packets to the data packet sorting combination device; the data packet sorting combination device outputs the received data packets; the CRC checker simultaneously outputs the CRC of the small data packets The verification result is sent to the response information generator; the response information generator outputs the response information.

Beneficial effects of the present invention;

A common practice is to add a cyclic redundancy check code to the entire data packet, and the receiving end performs cyclic redundancy check after error correction and decoding of the data packet. If there is one or several bit errors after error correction decoding , then the cyclic redundancy check cannot be passed, and the receiving end sends a negative acknowledgment message to request the sending end to retransmit the entire data packet.

The invention divides a user's data packet into multiple small data packets, and adds cyclic redundancy check codes of different lengths according to the importance of the information transmitted by each data packet. Bit error bits fall in one or several small data packets. Small data packets that contain erroneous bits cannot pass the cyclic redundancy check, while the rest of the small data packets that do not contain erroneous bits can pass the cyclic redundancy check, and the receiver can extract the information in it. Combined with retransmission, if all small data packets are received correctly at least once, the receiving end sends an acknowledgment message, and sorts and combines the correctly received small data packets according to the packet sequence number, which can reduce the average number of retransmissions of the automatic repeat request, Improve the effective throughput of the system, shorten the transmission delay, and reduce the packet loss rate. The present invention adopts different orders for each transmission of the automatic repeat request to arrange and combine the small data packets before encoding, modulating and sending, and the diversity gain in time or frequency can be obtained through retransmission.

Description of drawings

Fig. 1 is a schematic diagram of a transmission method for inserting a pilot signal into a header of a data packet;

Fig. 2 is a schematic diagram of a transmission method for inserting pilot signals at multiple specific positions in a data packet;

Fig. 3 is the schematic diagram of data packet segmentation method;

Fig. 4 is a schematic diagram of adding a packet sequence number to a small data packet;

Fig. 5 is a schematic diagram of adding a CRC check code to a small data packet;

Fig. 6 is a schematic diagram of the sending end sorting small data packets;

Fig. 7 is a block diagram of sending equipment;

Fig. 8 is a block diagram of receiving equipment;

FIG. 9 is a schematic diagram of packet segmentation in Embodiment 1;

Fig. 10 is a schematic diagram of adding a packet sequence number to a small data packet in Embodiment 1;

Fig. 11 is embodiment 1, the schematic diagram of adding CRC check codes of different lengths to small data packets;

Fig. 12 is a schematic diagram of arranging and combining small data packets in a specific order in Embodiment 1;

Fig. 13 is a schematic diagram of embodiment 1, where the receiving end extracts small data packets from decoded data packets;

Fig. 14 is a schematic diagram of embodiment 1, a small data packet CRC check result in the transmission process;

Fig. 15 is a schematic diagram of Embodiment 2, where the original data packet is divided into small data packets of the same length;

Fig. 16 is a schematic diagram of embodiment 2, adding a packet sequence number to a small data packet;

Fig. 17 is embodiment 2, the schematic diagram of small data packet adding same length CRC check code;

Fig. 18 is a schematic diagram of arranging and combining small data packets in a specific order in Embodiment 2;

Fig. 19 is a schematic diagram of embodiment 2, where the receiving end extracts small data packets from decoded data packets;

Fig. 20 is a schematic diagram of embodiment 2, the CRC check result of the small data packet during the transmission process.

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Detailed ways

Aiming at the data transmission in the wireless communication system, the invention proposes a data transmission method suitable for high-speed mobile terminals. The sending end divides the data packet into multiple small data packets, and adds a packet sequence number and CRC check code to each data packet. The sender sends the processed data packets in a specific order, and sends small data packets in a different order for each retransmission, so as to obtain diversity gain in time and frequency. The receiving end performs error correction and decoding on the received data packets, extracts small data packets in the specified order and length, performs CRC check on each small data packet, and sends ACK if all small data packets have been received correctly.

The present invention provides the following solutions:

The sender divides the data packet into multiple small data packets according to a specific length, and adds a packet sequence number and CRC check code to each small data packet. Arrange and combine all the processed small data packets in a specific order (a different order is used for each retransmission), input the generated data packets into the error correction encoder, and modulate and send the encoded data packets.

The receiving end demodulates the received signal to obtain data packets, and performs error correction and decoding on the data packets. Extract small data packets from decoded data packets in a specific order and length, perform CRC check on small data packets, and send ACK if all small data packets have been received correctly, if there are still small data packets that are not correct If received, a NAK is sent.

Using the above solution, the sender implements the following steps:

1. The sender divides the data packet into small data packets

The sender divides the original data packet into multiple small data packets. The length of each small data packet is agreed in advance between the sending end and the receiving end, without additional signaling interaction. As shown in Figure 3, there are two methods for splitting data packets:

Method 1: Divide the original data packet into multiple small data packets of equal length.

Method 2: Divide the original data packet into multiple small data packets with unequal lengths.

Important information, more important information and secondary information can be divided into different small data packets, and follow-up processing can be performed differently.

2. The sender adds a packet sequence number to each small data packet

As shown in Figure 4, the sender adds a sequence number to each small data packet. The length, format and location of the packet sequence number are agreed in advance between the sending end and the receiving end, without additional signaling interaction.

3. The sender adds a CRC check code for each small data packet

As shown in Figure 5, the sender adds a CRC check code for each small data packet. There are two methods for adding the CRC check code:

Method 1: Add a CRC check code of the same length to each small data packet

Method 2: Add CRC check codes of different lengths to each small data packet

The length of the CRC check code of each small data packet is agreed in advance between the sending end and the receiving end, and no additional signaling interaction is required. A longer check code can be added to a small data packet containing important information, and a shorter CRC check code can be added to a small data packet containing minor information.

4. The sender arranges the small data packets in a specific order

As shown in Figure 6, the sending end arranges and combines the small data packets added with the packet sequence number and CRC check code in a specific order. Different permutation orders can be used when sending new data packets and retransmitting data packets to obtain diversity gains in time and frequency. The sequence of small data packets used when sending new data packets and retransmitting data packets each time is agreed in advance between the sending end and the receiving segment, and no additional signaling interaction is required.

5. The sender encodes the data packet

The sending end performs error correction coding on the data packets generated after sorting and combining.

6. The sending end modulates the output bit stream of the encoder and sends it

The sending end modulates the data packet output by the encoder onto the carrier wave and sends it.

Using the above scheme, the receiving end realizes through the following steps:

1. The receiving end demodulates the received signal

The receiving end demodulates the received signal to obtain data packets.

2. The receiving end decodes the data packet

The receiving end performs error correction decoding on the data packet to obtain the decoded data packet.

3. The receiving end extracts small data packets

The receiving end extracts a small data packet of a specified length from the specified position of the decoded data packet.

4. The receiving end performs CRC check on the small data packet

The receiving end performs CRC check on each small data packet.

5. The receiving end generates a response message

The receiving end generates response information according to the results of CRC checks of all small data packets.

When receiving a new data packet, if any small data packet fails the CRC check, the receiving end generates a NAK.

When receiving a retransmitted data packet, combine the CRC check results of all previous transmissions of the data packet. If the retransmission is passed, all small data packets pass the CRC check at least once, and the receiving end generates an ACK.

When receiving a retransmitted data packet, combine the CRC check results of all previous transmissions of the data packet. If the retransmission is passed, there are still small data packets that have never passed the CRC check, and the receiving end generates a NAK.

6. The receiving end sorts and combines small data packets

The receiving end sorts and combines the correctly received small data packets according to the packet sequence number.

The invention provides a sending device suitable for high-speed mobile terminals. As shown in Figure 7, the device consists of the following functional modules:

Data packet divider, packet sequence number generator, CRC generator, data packet permutation and combination device, encoder, modulator, and sending device. in:

The data packet divider divides the data packet into small data packets according to the length agreed with the receiving end. The lengths of these small data packets can be the same or different.

Packet sequence number generator, which generates a unique packet sequence number for each small data packet.

The CRC generator generates a CRC check code for each small data packet according to the length agreed with the receiving end, and the length of the CRC check code of the small data packet can be the same or different.

The data packet arranging and combining device arranges and combines the small data packets added with the packet sequence number and CRC check code in the order agreed with the receiving end, and outputs "generated data packet". Each transmission of an auto-repeat request may sequence and combine small packets in the same or different order;

An encoder, performing error correction encoding on the "generated data packet", and outputting the encoded data packet;

The modulator modulates the encoded data packet onto the carrier;

The sending device selects to send a new data packet or to resend a data packet according to the content of the received response information.

The invention provides a receiving device suitable for high-speed mobile terminals. As shown in Figure 8, the device consists of the following functional modules:

A receiving device, a demodulator, a decoder, a data packet extracting device, a CRC checker, a data sorting and combining device, and a response information generator. in:

The receiving device is used to receive space wireless signals of a specific frequency;

The demodulator is used to demodulate the received signal to obtain the data packet;

Decoder, which performs decoding operation on the data packet, and outputs the decoded data packet;

The data packet extracting device extracts small data packets from the decoded data packets according to the position and length agreed with the sending end;

The CRC checker performs CRC check on the extracted small data packet;

The data packet sorting and combining device sorts and combines the small data packets according to the packet sequence number, and outputs the received data packets;

The response information generation device synthesizes the CRC check results of all small data packets to generate response information.

Example 1

sender:

As shown in Figure 9, the length of the original data packet is 200Byte, and the sender divides the data packet into three small data packets of different lengths:

A small data packet with a length of 40Byte stores the highest level of important information;

A small data packet with a length of 60 bytes, storing high-level general information;

A small data packet with a length of 100 bytes, storing low-level general information.

As shown in Figure 10, add a packet sequence number for each small data packet:

A small data packet with a length of 40Byte is added with a packet number 01;

Add packet number 10 to a small data packet with a length of 60Byte;

Add packet number 11 to a small data packet with a length of 100Byte;

According to the number of small data packets, the sending end and the receiving end agree on the length of the packet sequence number in advance.

As shown in Figure 11, add a CRC check code for each small data packet:

Data packet 1 adds a 32-bit CRC check code;

Data packet 2 adds a 32-bit CRC check code;

Packet 3 adds a 16-bit CRC check code.

As shown in Figure 12, the sender arranges and combines small data packets in a specific order:

The maximum number of transfers for hybrid automatic repeat requests is equal to 3,

When transmitting new data packets, arrange and combine small data packets in a specific order1;

When retransmitting data packets once, arrange and combine small data packets in a specific order 2;

When retransmitting data packets for the second time, arrange and combine small data packets in a specific order3.

The sending end encodes and modulates the data packets generated by permutation and combination before sending.

Receiving end:

Receive the wireless signal of the specified frequency, and demodulate the received signal to obtain the data packet;

The receiving end performs error correction decoding on the data packet to obtain the decoded data packet;

As shown in Figure 13, when receiving a new data packet, 354 bits (40Byte data, 2-bit packet sequence number, 32-bit CRC check code) of data packet 1 are extracted from the first bit of the decoded data packet; self-decoding Extract 514 bits of data packet 2 (60byte data, 2-bit packet serial number, 32-bit CRC check code) from the 355th bit of the last data packet; extract 818 bits of data packet 3 from the 869th bit of the decoded data packet (100byte data, 2-bit packet serial number, 16-bit CRC check code).

When receiving a retransmitted data packet, extract 514 bits of data packet 2 (60byte data, 2-bit packet sequence number, 32-bit CRC check code) from the first bit of the decoded data packet, and the decoded data packet Extract the 818 bits of data packet 3 (100byte data, 2-bit packet sequence number, 16-bit CRC check code) from the 515th bit of the decoded data packet, and extract the 354 bits of data packet 1 (40byte data , 2-bit packet number, 32-bit CRC check code).

When receiving the second retransmitted data packet, extract 818 bits of data packet 3 (100byte data, 2-bit packet serial number, 16-bit CRC check code) from the first bit of the decoded data packet; Extract 354 bits of data packet 1 (40byte data, 2-bit packet sequence number, 32-bit CRC check code) from the 819th bit of the packet; extract 514 bits of data packet 2 (60byte data, 2-bit packet serial number, 32-bit CRC check code).

The transmission process of a data packet is shown in Figure 14:

During the initial transmission, the small data packet 2 passes the CRC check, and the receiving end generates a negative response message;

In the first retransmission, the small data packet 3 passed the CRC check, and so far the small data packet 1 has never passed the CRC check, and the receiving end generates a negative response message.

During the second retransmission, the small data packets 3 and 1 pass the CRC check, so far all the small data packets have passed the CRC check at least once, and the receiving end generates a positive response message.

The receiving end sorts and combines the correctly received small data packets according to the sequence numbers of the packets.

Example 2

sender:

As shown in Figure 15, the length of the original data packet is 400Byte. The sender divides the data packet into four small data packets of the same length, and transmits the highest-level important information, high-level important information, and low-level general information respectively.

As shown in Figure 16, add a 4-bit packet sequence number for each small data packet;

As shown in Figure 17, add a 32-bit CRC check code for each small data packet;

As shown in Figure 18, the sender arranges and combines small data packets in a specific order:

The maximum number of transfers for mixed automatic repeat requests is equal to 4,

When transmitting new data packets, arrange and combine small data packets in a specific order1;

When retransmitting data packets once, arrange and combine small data packets in a specific order 2;

When retransmitting data packets for the second time, arrange and combine small data packets in a specific order3;

When retransmitting data packets three times, arrange and combine small data packets in a specific order4.

Receiving end:

Receive the wireless signal of the specified frequency, and demodulate the received signal to obtain the data packet;

The receiving end performs error correction decoding on the data packet to obtain the decoded data packet;

As shown in Figure 19, when receiving a new data packet, 836 bits (100Byte data, 4-bit packet sequence number, 32-bit CRC check code) of data packet 1 are extracted from the first bit of the decoded data packet; self-decoding Extract 836 bits of data packet 2 from the 837th bit of the last data packet (100byte data, 4-bit packet number, 32-bit CRC check code); extract 836 bits of data packet 3 from the 1673rd bit of the decoded data packet (100byte data, 4-bit packet serial number, 32-bit CRC check code); extract 836 bits of data packet 4 from the 2509th bit of the decoded data packet (100byte data, 4-bit packet serial number, 32-bit CRC check code ).

When receiving a retransmitted data packet, extract 836 bits of data packet 2 (100Byte data, 4-bit packet serial number, 32-bit CRC check code) from the first bit of the decoded data packet; Extract 836 bits (100byte data, 4-bit packet sequence number, 32-bit CRC check code) of data packet 3 from the 837th bit of the decoded data packet; extract 836 bits (100byte data , 4-bit packet sequence number, 32-bit CRC check code); 836 bits (100byte data, 4-bit packet sequence number, 32-bit CRC check code) of data packet 1 are extracted from the 2509th bit of the decoded data packet.

When receiving the second retransmitted data packet, extract 836 bits of data packet 3 (100Byte data, 4-bit packet sequence number, 32-bit CRC check code) from the first bit of the decoded data packet; From the 837th bit of the packet, extract the 836 bits (100byte data, 4-bit packet sequence number, 32-bit CRC check code) of the data packet 4; from the 1673rd bit of the decoded data packet, extract the 836 bits (100byte data, 4-bit packet sequence number, 32-bit CRC check code); extract 836 bits of data packet 2 (100byte data, 4-bit packet sequence number, 32-bit CRC check code) from the 2509th bit of the decoded data packet.

When receiving three retransmitted data packets, extract 836 bits of data packet 4 (100Byte data, 4-bit packet serial number, 32-bit CRC check code) from the first bit of the decoded data packet; Extract the 836 bits of data packet 1 (100byte data, 4-bit packet sequence number, 32-bit CRC check code) from the 837th bit of the decoded data packet; extract the 836 bits of data packet 2 (100byte data , 4-bit packet sequence number, 32-bit CRC check code); extract 836 bits (100byte data, 4-bit packet sequence number, 32-bit CRC check code) of data packet 3 from the 2509th bit of the decoded data packet.

The transmission process of a certain data packet is shown in Figure 20:

During the initial transmission, the small data packets 1 and 3 pass the CRC check, and the receiving end generates a negative response message;

During the first retransmission, the small data packets 1 and 2 passed the CRC check, and so far the small data packet 4 has never passed the CRC check, and the receiving end generates a negative response message.

During the second retransmission, the small data packets 1 and 4 pass the CRC check, so far all the small data packets have passed the CRC check at least once, and the receiving end generates a positive response message.

The receiving end sorts and combines the correctly received small data packets according to the sequence numbers of the packets.

Claims (10)

1. A data transmission method suitable for high-speed mobile terminals, comprising a data sending method and a data receiving method, characterized in that: The data sending method includes the following steps: 1) The sending end divides the original data packet into multiple small data packets; 2) The sender adds a packet sequence number to each small data packet; 3) The sending end adds a cyclic redundancy check code for each small data packet; 4) The sender arranges and combines the small data packets in the specified order; 5) The sending end performs error correction coding on the data packets generated after permutation and combination; 6) The sending end modulates and sends the encoded data packet; The data receiving method includes the following steps: 1) The receiving end receives the wireless signal, and demodulates the received signal to obtain the data packet; 2) The receiving end performs error correction and decoding on the data packet to obtain the decoded data packet; 3) The receiving end extracts small data packets from the decoded data packets; 4) The receiving end performs a cyclic redundancy check on each small data packet; 5) The receiving end generates response information according to the results of all small data packet cyclic redundancy checks; 6) The receiving end sorts and combines the correctly received small data packets according to the sequence numbers of the packets. 2. by the described method of claim 1, it is characterized in that: sending end divides original data packet into a plurality of small data packets, the length of these small data packets can be identical also can be different, and each small data packet The package sequence number of the package is unique. 3. by the described method of claim 1, it is characterized in that also comprising: sender adds cyclic redundancy check code for each small data packet, the length of the cyclic redundancy check code of each small data packet can be identical can also be different. 4. The method according to claim 1, further comprising: arranging and combining the small data packets in a specified order at each transmission sending end. 5. The method according to claim 1, further comprising: the sending end can arrange and combine the small data packets in the same order or in different orders for each transmission. 6. The method according to claim 1, wherein the receiving end extracts a small data packet of a specified length from a specified position of the decoded data packet in a specified order. 7. The method according to claim 1, further comprising: the receiving end can extract a small data packet of a specified length from a specified position of the decoded data packet in the same order or in a different order for each transmission. 8. The method according to claim 1, further comprising: when receiving a new data packet, if a small data packet is not passed through the cyclic redundancy check, the receiving end generates a negative response message; or when receiving a retransmission data packet , combined with the cyclic redundancy check results of all transmissions before the data packet, if all the small data packets have been received correctly, the receiving end generates an acknowledgment message. 9. A kind of data transmission method that is applicable to high-speed mobile terminal according to claim 1, it is characterized in that also comprising: when receiving retransmission data packet, combine the cyclic redundancy check of all the small data packets of transmission before this data packet As a result of the test, if there are still small data packets that have never been received correctly, the receiving end generates a negative acknowledgment message. 10. A data transmission device suitable for high-speed mobile terminals, comprising a sending device and a receiving device; it is characterized in that the sending device includes: Divide the data packet into small data packets according to the specified length, and the length of these small data packets can be the same or different data packet splitters; A packet sequence number generator that generates a unique packet sequence number for each small data packet; Generate a cyclic redundancy check code of a specified length for each small data packet, the length of the small data packet cyclic redundancy check code can be the same or different cyclic redundancy check code generator; Permutation and combination of small data packets with added packet sequence numbers and cyclic redundancy check codes in a specified order, data packet permutation that can permutate and combine small data packets in the same or different order for each transmission of an automatic repeat request combination device; an encoder for error-correcting encoding of the data packets; A modulator that modulates the encoded data packet onto the carrier; Select a sending device for sending a new data packet or resending a data packet according to the content of the received response information; Receiving equipment includes: A receiving device for receiving space wireless signals of a specific frequency; A demodulator that demodulates the received signal to obtain the data packet; Perform a decoding operation on the data packet, and output a decoder for the decoded data packet; A data packet extraction device for extracting small data packets from the decoded data packets according to the position and length agreed with the sending end; a cyclic redundancy checker for performing a cyclic redundancy check on the extracted packet; Sorting and combining the small data packets according to the packet sequence numbers, and outputting a data packet sorting and combining device for receiving the data packets; A response information generator that synthesizes the cyclic redundancy check results of all small data packets to generate response information; The data packet splitter outputs the divided small data packet to the packet serial number generator; the packet serial number generator outputs the small data packet added with the packet serial number to the CRC generator; the CRC generator outputs the small data packet added with the CRC check code to the The data packet permutation and combination device; the data packet permutation and combination device outputs the permuted and combined data packets to the encoder; the encoder outputs the encoded data packets to the modulator; the modulator outputs the modulated signal to the sending device; the sending device sends the modulated The signal is sent out; The receiving device outputs the signal to the demodulator; the demodulator outputs the data packet to the decoder; the decoder outputs the decoded data packet to the data packet extraction device; the data packet extraction device outputs the small data packet to the cyclic redundancy check The cyclic redundancy checker outputs the correctly received small data packets to the data packet sorting and combining device; the data packet sorting and combining device outputs the received data packets; the CRC checker simultaneously outputs the CRC check result of the small data packets to the response information generation device; the response information generator outputs the response information.

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