CN109861797B

CN109861797B - Data transmission method and system

Info

Publication number: CN109861797B
Application number: CN201711461003.5A
Authority: CN
Inventors: 南书志; 杨之佐; 刘慎发; 王凯; 鲍东山
Original assignee: Nufront Mobile Communications Tech Co Ltd
Current assignee: Nufront Mobile Communications Tech Co Ltd
Priority date: 2017-12-28
Filing date: 2017-12-28
Publication date: 2022-07-15
Anticipated expiration: 2037-12-28
Also published as: CN109861797A

Abstract

The invention provides a data transmission method, which can perform fragmentation processing on data according to available channel resources and comprises the following steps: a sending end sends a plurality of data frames and/or fragment data according to the resources distributed by the channel; confirming the successfully received data frame and/or the fragmented data according to the confirmation management frame fed back by the receiving end; retransmitting unsuccessfully received data frames and/or fragmented data; and when the retransmission is carried out, the data frame and/or the fragment data are subjected to fragment processing again according to the current available resources. The channel resources can be used to the maximum extent and are not influenced by the fixed fragment size; the method can avoid a large number of fragmentations under the condition of sufficient resources, reduce the cost of wireless resources, reduce the processing time of a processor and reduce the overall cost; through immediate confirmation, the multiple transmission of the confirmed receiving fragments is avoided, and meanwhile, the network delay is effectively reduced.

Description

Data transmission method and system

Technical Field

The invention belongs to the technical field of wireless communication, and particularly relates to a data transmission method and a data transmission system.

Background

In network data Transmission, fragmentation is beneficial to a network in which a network packet passes through a Maximum Transmission Unit (MTU) that is shorter than the packet length. Under the condition that wireless channel fading, multipath fading and inter-channel interference are serious, the fragmented transmission is adopted, so that the retransmission of the whole frame of data caused by channel error codes can be avoided, and the overall transmission success rate of the data is improved. However, if the fragmentation is too small, there are more overheads such as packet header and fragmentation information, and the proportion of payload is small, which may cause waste of network resources. At present, network data fragmentation is generally performed according to a fixed size, and various different network environments are adapted by adjusting the size of the fragmentation. The fragment mode generally adopts offset to position the data position, and the receiving end judges whether all fragment data are received after receiving the fragments and then synthesizes a whole packet. This approach has the following disadvantages:

Firstly, the signaling overhead caused by fragmentation is large, the transmitting end indicates the fragmentation number in the data transmission process, and the receiving end confirms each fragmentation to cause large signaling overhead.

Secondly, the fragmentation size is fixed, and the resources of the wireless link are changing continuously. Therefore, setting a larger fragmentation threshold will cause a waste of radio resources at most equivalent to the fragmentation threshold, and setting a smaller fragmentation threshold will cause a larger signaling overhead. This contradiction is particularly prominent in wireless communication scenarios with high-speed movement. Two requirements are caused by rapid change of wireless channels caused by high-speed movement, on one hand, in low signal to noise ratio, narrow bandwidth, low Modulation and Coding Scheme (MCS), and multi-user scenarios, because channel resources are limited, a smaller fragmentation design is required to improve the utilization rate of wireless resources. On the other hand, at high snr, the need for high throughput requires a reduction of the signaling overhead due to fragmentation.

Thirdly, a large number of fragments can bring burden to a processor and storage, and the cost of equipment is increased.

And fourthly, the sender does not determine the receiving condition of the receiver in the sub-slice mode. Every retransmission needs to retransmit all fragments, wasting network bandwidth.

And fifthly, once the fragments are lost, the sender confirms the condition of retransmission, and the time delay is large.

In order to solve the above problems, improve the utilization rate of wireless resources and reduce the signaling overhead caused by fragmentation, the present document proposes an immediate acknowledgement fragmentation data transmission scheme, which can utilize network resources to the maximum extent, and does not need to fragment all long frames into short frames, nor needs to retransmit all fragments every time, thereby achieving the maximum utilization rate of network resources and reducing the signaling overhead caused by fragmentation.

Disclosure of Invention

In view of this, the technical problem to be solved by the present invention is to provide a method for transmitting wireless communication data, which employs a fragmentation technical scheme that uses a non-fixed fragmentation length and performs fragmentation based on the size of available wireless network data resources, so as to effectively reduce the number of fragments and use network resources to the maximum extent.

The data transmission method provided by the invention can perform fragmentation processing on data according to available channel resources, and comprises the following steps:

a sending end sends a plurality of data frames and/or fragment data according to the resources distributed by the channel;

confirming the successfully received data frame and/or the fragmented data according to the confirmation management frame fed back by the receiving end; retransmitting unsuccessfully received data frames and/or fragmented data;

When retransmission is carried out, the data frame and/or the fragment data are subjected to fragment processing again according to the current available resources.

The sending end sending a plurality of data frames and/or fragmented data according to the resource allocated by the channel specifically includes:

the sending end sequentially takes out data from the data to be sent to judge whether the wireless resources are enough to send the data packet, and if the resources are enough, all the remaining data of the data packet are sent; and if the number of the wireless resources is not enough, the data packet is fragmented according to the number of the remaining wireless resources, and the size of the fragmentation is equal to the number of the remaining wireless resources.

Specifically, after receiving the data frame and/or the fragment data, the receiving end confirms through responding to a confirmation management frame; and the confirmation management frame is provided with an identification bit for indicating whether the confirmation opposite end successfully receives.

The invention also provides a data transmission system, which can process data in a slicing way according to the available channel resources, and the system comprises:

the system comprises a sending end and a receiving end, wherein the sending end is used for sending a plurality of data frames and/or fragment data according to resources distributed by a channel;

the receiving end feeds back a confirmation management frame to the sending end for confirmation after receiving the data frame and/or the fragment data;

the sending end confirms the successfully received data frame and/or the fragment data according to the confirmation management frame fed back by the receiving end; retransmitting unsuccessfully received data frames and/or fragmented data;

the sending end sequentially takes out data from the data to be sent to judge whether the wireless resources are enough to send the data packet, and if the resources are enough, all the residual data of the data packet are sent; and if the number of the wireless resources is not enough, the data packet is fragmented according to the number of the remaining wireless resources, and the size of the fragmentation is equal to the number of the remaining wireless resources.

In summary, the method and system for transmitting wireless communication data according to the present invention can perform fragmentation processing on data according to available channel resources, and compared with the prior art, can use the channel resources to the maximum extent, and is not affected by the size of the fixed fragments; the method can avoid carrying out a large amount of fragmentation under the condition of sufficient resources, reduce the cost of wireless resources, reduce the processing time of a processor and reduce the overall cost; through immediate confirmation, the multiple transmission of the confirmed receiving fragments is avoided, and meanwhile, the network delay is effectively reduced.

For the purposes of the foregoing and related ends, the one or more embodiments include the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative aspects and are indicative of but a few of the various ways in which the principles of the various embodiments may be employed. Other benefits and novel features will become apparent from the following detailed description when considered in conjunction with the drawings and the disclosed embodiments are intended to include all such aspects and their equivalents.

Drawings

FIG. 1 is a diagram illustrating a packet format for transmission in an embodiment of the present invention;

FIG. 2 is a diagram of a frame body structure of an acknowledgment management frame fed back by a receiving end in an embodiment of the present invention;

FIG. 3 is a diagram illustrating a physical frame structure according to an embodiment of the present invention;

fig. 4a, 4b, 4c and 4d are schematic diagrams of a data transmission state according to an embodiment of the invention.

Detailed Description

The following description and the drawings sufficiently illustrate specific embodiments of the invention to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. The examples merely typify possible variations. Individual components and functions are optional unless explicitly required, and the sequence of operations may vary. Portions and features of some embodiments may be included in or substituted for those of others. The scope of embodiments of the invention encompasses the full ambit of the claims, and all available equivalents of the claims. Embodiments of the invention may be referred to herein, individually or collectively, by the term "invention" merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed.

The invention provides a new fragmentation scheme, which does not fix the length of the fragments and fragments the fragments according to the size of the available wireless network data resources. The scheme adopts an immediate confirmation mode, and the sender can determine the data which is correctly received by the receiving end through immediate confirmation, so that the situation that the correct data is confirmed to be received by the receiving end is avoided from being meaningless retransmitted, and the length is adjusted in real time according to the channel resources to furthest use the network resources. Through immediate confirmation, the time delay can be reduced, and the network response time is prolonged.

In order to achieve the object of the present invention, the present invention provides a data transmission method, which can perform fragmentation processing on data according to available channel resources, and includes:

and when the retransmission is carried out, the data frame and/or the fragment data are subjected to fragment processing again according to the current available resources.

the sending end sequentially takes out data from the data to be sent to judge whether the wireless resources are enough to send the data packet, and if the resources are enough, all the residual data of the data packet are sent; if not, the data packet is fragmented according to the current remaining wireless resource quantity, and the size of the fragmentation is equal to the current remaining wireless resource quantity.

In the present invention, the format of the transmitted data packet is shown in fig. 1.

The invention adds general MAC head and FCS check on the wireless network transmission data packet to form MAC Protocol Data Unit (MPDU), the frame format of MPDU is shown in figure 1. As shown in fig. 1, each MPDU may be divided into three portions.

The first part is a generic MAC header of fixed length.

The second portion is the payload carried by the MPDU.

The third part is check (FCS) information.

All the bits contained in the fields in the MAC frame are numbered from low to high and transmitted to the physical layer in the order from low to high. Bits within one byte are transferred to the physical layer in order from Left (LSB) to right (MSB). The bits contained in the same field correspond to decimal numbers such as b9-b 11-000 in the order of numbering from low to high, corresponding to 0; b9-b11 is 001, corresponding to 4.

The meaning of the fields of the generic MAC header is as follows:

A. frame control

The frame control includes protocol version, data flow information, frame type, etc.

B. Slice Number (FSN) field:

the fragment number field length is 4 bits, and is used for indicating the number of each fragment of the MPDU, and the value range is 0-15. When the MPDU has only one fragment, the fragment number is 0; when the MPDU has a plurality of slices, the first slice number thereof is 0. The slice numbers of different slices of the same MPDU are incremented by 1.

C. Sequence Number (SN) field

The sequence number field is 12 bits in length and ranges from 0 to 4095 to indicate the sequence number of the MPDU. All transmitted MPDUs within a data stream are assigned a sequence number. The first MPDU sequence number is 0 and the sequence numbers of different MPDUs are incremented by 1.

D. A fragment indication field:

the slice indication field is 1 bit in length. In all data frames or sequence number management control frames, if fragments of the current MPDU exist later, the field is set to 1; otherwise, this field is set to 0.

E. Length field

The length field is 12 bits and represents the total byte length of all fields between the MAC header field and the FCS field.

The acknowledgement of the data packet is realized by a bitmap in the field of the acknowledgement management frame. The frame body structure of the ack management frame fed back by the receiving end is shown in fig. 2, where the set fields include: a Start Serial Number (SSN) bitmap for indicating which of the MPDUs or fragments have been successfully received by the receiving end.

The meaning of each field of the frame body of the acknowledgement management frame is shown in table 1.

Table 1 body description of acknowledgement management frame

The present invention defines a physical frame divided into a downlink period and an uplink period, and the structure of the physical frame is shown in fig. 3. In the downlink period, the CAP sends acknowledgement information DACK and downlink data of the uplink data to the STA, and in the uplink period, the STA sends acknowledgement information UACK and uplink data of the downlink data to the CAP. And multiple MPDUs can be received or sent in the uplink and downlink periods, and simultaneously, the multiple MPDUs are immediately confirmed through bitmaps in DACK or UACK. Because the uplink and downlink service data are independent, the party sending the service data is defined as a sending end, and the party receiving the service data is defined as a receiving end.

In the invention, the sending end needs to obtain the confirmation information of the last sending condition before sending each time. The sending end can send a plurality of whole frame data and/or fragment data according to the number of resources allocated to the channel. And the sending end sequentially takes out the data from the data to be sent to judge whether the wireless resources are enough to send the data packet, and if the resources are enough, all the residual data of the data packet are sent. And if the number of the wireless resources is not enough, the data packet is fragmented according to the number of the remaining wireless resources, and the size of the fragmentation is equal to the number of the remaining wireless resources.

And after receiving the MPDU/fragment data, the receiving end confirms through responding to the confirmation management frame. Every 1bit in the acknowledgement management frame Bitmap indicates whether a certain MPDU/fragment is successfully received. And the transmitting end confirms whether the opposite end successfully receives the data according to the bit information in the Bitmap.

For the fragment packets which are not received by the receiving end, the length of the fragment data packet is not required to be consistent with the last length when the transmitting end retransmits the fragment packets again. In order to prevent the ACK loss, the fragment data received by the receiving end needs to check whether the sequence number and the fragment number of the current fragment data are consistent with the received sequence number and the received fragment number. If consistent indicates that the previously replied ACK was lost, the current fragment is used in place of the last received fragment.

For the fragment packet received by the receiving end, the transmitting end transmits the next fragment according to the position of the last fragment, and the size of the next fragment is related to the size of the wireless channel resource which is currently obtained. The transmitting end can fragment the same data packet for multiple times according to the change of the wireless channel, and the receiving end splices the complete data messages with the same serial number at the receiving end according to the fragment number.

For the whole packet which is not received by the receiving end, the transmitting end can perform fragmentation when retransmitting again, and the fragmentation mechanism is the same as that of the primary fragmentation, so that a plurality of fragments corresponding to the whole packet with different serial numbers may need to be transmitted in one physical frame.

The same physical frame only allows one SN number to occur, but multiple data packets of different SNs can be sent. Once the fragment request of a packet of service data is confirmed, the packet of service data is not sent according to the whole packet format.

Examples

If there are 4 packets of 1.5kB to be transmitted, the SN numbers of the packets are 1, 2, 3, and 4, respectively. The resource of the 1 st frame is 5kB, which can send the whole packet with SN number 1/2/3 and 500-byte fragment with SN equal to 4, assuming that receiving ACK as shown in fig. 4a, the SN1/2 transmission failure requires retransmission.

If the resource of the 2 nd frame is 500 bytes, the SN1 data packet is preferentially sent. Since the available resources (or remaining resources) are only 500 bytes, the SN1 data is fragmented. Assume that the ACK received case is as shown in fig. 4 b. SN1 is successfully transmitted in fragment 0, and the rest is sent continuously in the next frame.

If the resource of the 3 rd frame is 1.5kB, the remaining fragment of the SN1 data packet and partial data of the SN2 are continuously sent, and it is assumed that receiving ACK is as shown in fig. 4c, transmission of the SN1 fragment 1 fails, and transmission of the SN2 fragment 0 succeeds.

And if the resource of the 4 th frame is 3kB, the rest fragments of the SN1/2/4 data packet are sent, and if the ACK receiving condition is shown in the figure 4c, the SN1/2/4 fragments are successfully transmitted.

To this end all data transfer is completed.

Compared with the fixed fragmentation threshold scheme in the prior art, the invention has the following advantages:

1. can use the channel resource to the maximum extent and is not influenced by the fixed fragment size

2. The method can avoid a large number of fragmentations under the condition of sufficient resources, reduce the cost of wireless resources, reduce the processing time of a processor and reduce the overall cost

3. Through immediate confirmation, the multiple transmission of the confirmed receiving fragments is avoided, and meanwhile, the network delay is effectively reduced.

Those of skill in the art will understand that the various exemplary method steps and apparatus elements described in connection with the embodiments disclosed herein can be implemented as electronic hardware, software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative steps and elements have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The steps of a method described in connection with the embodiments disclosed above may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a subscriber station. In the alternative, the processor and the storage medium may reside as discrete components in a subscriber station.

The disclosed embodiments are provided to enable those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the scope or spirit of the invention. The above-described embodiments are merely preferred embodiments of the present invention, which should not be construed as limiting the invention, and any modifications, equivalents, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A data transmission method, wherein the MAC layer data is sliced according to available channel resources in a physical frame, comprising:

the sending end sequentially sends a plurality of MAC layer data frames and/or fragment data according to the distributed channel resources, wherein the sending end sequentially takes out data from the data to be sent to judge whether the wireless resources are enough to send the data packet, and if the resources are enough, all the residual data of the data packet are sent; if not, the data packet is fragmented according to the number of the remaining wireless resources of the current physical frame, and the size of the fragmentation is equal to the number of the remaining wireless resources of the current physical frame; in each sending period, the data serial numbers sent in sequence are increased progressively, and one data frame only allows one fragment at most or transmits the whole frame of data;

after receiving the MAC layer data frame and/or the fragment data, the receiving end confirms the management frame by responding immediately; the confirmation management frame is provided with an identification bit for indicating whether the confirmation opposite terminal successfully receives: and immediately confirming the successfully received MAC layer data frame and/or the successfully received fragment data according to a confirmation management frame fed back immediately by a receiving end, and confirming by using a bitmap (bitmap) mode: the receiving end takes the serial number of the data frame and/or the fragment data successfully received by the first packet in the current period as the initial serial number of a confirmation management frame bitmap (bitmap), and marks and immediately confirms all the successfully received data frames and/or fragment data in the current period by using corresponding bits in the confirmation management frame bitmap; the transmitting end retransmits the MAC layer data frame and/or the fragmented data which are not successfully received in the next transmitting period;

And when retransmission is carried out, the MAC layer data frame and/or the fragment data are subjected to fragment processing again according to the available resources of the current physical frame.

2. A data transmission system for slicing MAC layer data based on available channel resources in a physical frame, the system comprising:

the transmitting end is used for sequentially transmitting a plurality of MAC layer data frames and/or fragment data according to the allocated current physical frame channel resources; the sending end sequentially takes out data from the data to be sent to judge whether the wireless resources are enough to send the data packet, and if the resources are enough, all the residual data of the data packet are sent; if not, the data packet is fragmented according to the number of the remaining wireless resources of the current physical frame, and the size of the fragmentation is equal to the number of the remaining wireless resources of the current physical frame; in each sending period, the sequence numbers of the data sent in sequence are increased progressively, and one data frame only allows one fragment at most or transmits the whole frame of data;

the receiving end immediately feeds back a confirmation management frame to the sending end for confirmation after receiving the MAC layer data frame and/or the fragment data; the confirmation management frame is provided with an identification bit for indicating whether the confirmation opposite terminal successfully receives:

The sending end instantly confirms the successfully received MAC layer data frame and/or fragment data according to the confirmation management frame fed back by the receiving end, and confirms by using a bitmap (bitmap) mode: the receiving end takes the serial number of the data frame and/or the fragment data successfully received by the first packet in the current period as the initial serial number of a confirmation management frame bitmap (bitmap), and marks and immediately confirms all the successfully received data frames and/or fragment data in the current period by using corresponding bits in the confirmation management frame bitmap; a transmitting end retransmits the unsuccessfully received MAC layer data frame and/or the fragmented data in the next transmitting period;

and when retransmission is carried out, the MAC layer data frame and/or the fragment data are subjected to fragment processing according to the available resources of the current physical frame.