CN102137441B - method, device and system for data transmission - Google Patents

Abstract

The invention discloses a data transmission method, device and system. The method includes: receiving a protocol data unit PDU, the first identifier in the header information of the PDU indicates whether the data in the PDU is retransmission data. The data transmission method disclosed in the embodiment of the present invention can solve the cumbersome process of determining whether the received PDCP PDU contains retransmission data in the prior art, and improves the efficiency of the transmission process.

Description

Data transmission method, device and system

technical field

The present invention relates to the communication field, in particular to a data transmission method, device and system.

Background technique

LTE (Long Term Evolution, long-term evolution) is a long-term evolution version of the third-generation wireless mobile communication protocol. LTE user protocols include: PDCP (Packet Data Convergence Protocol, packet convergence protocol), RLC (Radio Link Control, radio link control), MAC (Medium Access Control, media access control) and PHY (Physical Layer, physical layer) . Among them, the main functions of PDCP are: header compression of IP data packets, encryption and decryption of data, timer discarding, retransmission and reordering processing upon re-establishment.

The receiver determines whether to discard the received data according to the SN associated with the PDCP PDU. The process is: if the received PDCP PDU SN is smaller than the last PDCP PDU SN submitted to the upper layer, it is considered that the sender has received a duplicate due to switching and retransmission. The sent data needs to be discarded; or if the difference between the received PDCP PDU SN and the last PDCP PDU SN submitted to the upper layer is greater than half of the PDCP receiving window size, it will also be judged to be received by the sender because of switching The data sent repeatedly by retransmission is discarded.

In the prior art, the receiver determines whether the received PDCP PDU contains retransmission data according to the SN of the received PDCP PDU and the SN of the last PDCP PDU submitted by the receiver to the upper layer. The judgment process is cumbersome, resulting in low efficiency of data transmission. Low.

Contents of the invention

An aspect of the present invention provides a data transmission method, comprising:

Receiving a protocol data unit PDU, the first identifier in the header information of the PDU indicates whether the data in the PDU is retransmission data;

If the first identifier indicates that the data in the PDU is retransmission data, and the PDU is not a PDU received outside the reordering window, and the same PDU as the PDU has been buffered, the PDU is discarded; or,

If the first identifier indicates that the data in the PDU is retransmission data, and the PDU is a PDU received outside the reordering window, discarding the PDU; or,

If the first identifier indicates that the data in the PDU is retransmission data, the PDU is not a PDU received outside the reordering window, and the same PDU as the PDU is not cached, cache the PDU.

Another aspect of the present invention provides a data transmission method, comprising:

Send a protocol data unit PDU, the first identifier in the header information of the PDU indicates whether the data in the PDU is retransmission data, so that the PDU receiver performs the following steps after receiving the PDU:

The PDU receiver judges whether the data in the PDU is retransmission data according to the first identifier;

If the first identifier indicates that the data in the PDU is retransmission data, and the PDU is not a PDU received outside the reordering window, and the same PDU as the PDU has been buffered, the PDU is discarded; or,

If the first identifier indicates that the data in the PDU is retransmission data, and the PDU is a PDU received outside the reordering window, discarding the PDU; or,

When the first identifier indicates that the data in the PDU is retransmission data, the PDU is not a PDU received outside the reordering window, and the same PDU as the PDU is not cached, cache the PDU.

Another aspect of the invention provides an apparatus comprising:

A receiving unit, configured to receive a protocol data unit PDU, the first identifier in the header information of the PDU indicates whether the data in the PDU is retransmission data;

A processing unit configured to discard the PDU when the first identifier indicates that the data in the PDU is retransmission data, the PDU is not a PDU received outside the reordering window, and the same PDU has been buffered; or , when the first identifier indicates that the data in the PDU is retransmission data, and the PDU is a PDU received outside the reordering window, discarding the PDU; or, when the first identifier indicates that the If the data in the PDU is retransmission data, the PDU is not a PDU received outside the reordering window, and the same PDU is not cached, the PDU is cached.

Another aspect of the invention also provides a system.

In the embodiment of the present invention, the header information of the PDU sent by the data sender includes a first identifier, and the first identifier is used to indicate whether the data in the PDU is retransmission data. After receiving the data, the receiver passes Identifying and judging whether the data in the PDU is retransmission data or initial transmission data, and discarding the qualified PDUs with retransmission data, which changes the discrimination method of discarding processing in the prior art, and simplifies judging whether the data in the PDU is For the process of retransmitting data, the efficiency of the transmission process is improved.

Further, this method directly identifies the data in the sent PDU, without relying on the SN of the PDCP PDU received during the data transmission process and the SN of the PDCP PDU submitted by the PDCP receiver to the upper layer last time, which improves the reliability of the discrimination result and accuracy, avoiding the phenomenon of discarding normally sent data caused by the inconsistency of the state variables of the data receiver and the sender.

Description of drawings

Fig. 1 is the structural representation of the PDCP PDU that an embodiment of the present invention provides;

FIG. 2 is a flowchart of a data transmission method provided by an embodiment of the present invention;

FIG. 3 is a flowchart of another data transmission method provided by an embodiment of the present invention;

Fig. 4 is a schematic structural diagram of a device provided by an embodiment of the present invention;

Fig. 5 is a schematic structural diagram of another device provided by an embodiment of the present invention;

Fig. 6 is a schematic structural diagram of the system provided by the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

An embodiment of the present invention provides a data transmission method, wherein a protocol data unit (PDU) is sent, and a first identifier in the header information of the PDU indicates whether the data in the PDU is retransmission data.

Taking the PDCP PDU as an example, the structure of the PDU is shown in Figure 1. The R_TX in the header information of the PDU is the retransmission bit that identifies whether the data is retransmission data. For example, when R_TX is 1, it means that the data in the PDU is retransmitted by the sender, and when R_TX is 0, it means that the data in the PDU is initial transmission data, that is, it is not data retransmitted by the sender. For another example, when R_TX is True, it means that the data in the PDU is data retransmitted by the sender; when R_TX is False, it means that the data in the PDU is initial transmission data.

This embodiment is applicable to the data transmission process in confirmation mode, that is, in the method provided by this embodiment, the data sender can identify whether the data is heavy by setting the value of the first identifier during the process of generating the PDU. Data transmission, so that the receiver can directly determine whether the received PDU contains retransmission data according to the first identifier, which simplifies the receiver's identification process for retransmission data, improves the efficiency and reliability of data transmission, and saves air interface resources .

This embodiment does not limit that the structural improvement method is only applicable to PDCP PDUs, and can also be applied to other protocol data units. For example, the header information of the protocol data units of the MAC layer includes retransmission bits, and the The data is marked, which simplifies the process of judging whether the data in the PDU is retransmitted data, and improves the efficiency of the transmission process.

As shown in FIG. 2 , another embodiment of the present invention provides a data transmission method, including the following steps.

Step S21, receiving a protocol data unit PDU, the first identifier in the header information of the PDU indicates that the data in the PDU is retransmission data.

Step S22, judging according to the first identifier that the data in the received PDU is retransmission data.

In this embodiment, the data receiver judges whether the data in the PDU is retransmitted data through the first identifier in the received PDU, which simplifies the process of judging retransmitted data and improves the efficiency and reliability of protocol transmission.

This embodiment may also include the following steps.

Step S23, judging whether the PDU is a PDU outside the reordering window, if yes, execute step S25; otherwise, execute step S24.

For example, the process of judging whether it is a PDU outside the reordering window is: obtaining the difference between the sequence number SN of the PDU and the PDU SN submitted to the upper layer last time. When the difference is greater than the length of the reordering window, the PDU For PDUs received outside the reordering window. Wherein, the size of the reordering window can be set according to actual conditions, for example, the size of the reordering window is set to half of the number of SNs. Assuming that the number of SNs is 4096, the reordering window size is 2048. Assuming that the number of SNs is 8192, the reordering window size is 4096.

When the data in the PDU is initial transmission data, it can be cached and sorted and then directly submitted to the upper layer, such as the layer application above the protocol layer corresponding to the PDU, which will not be repeated here.

Step S24, judging whether the same PDU as the PDU is cached, if yes, execute step S25; otherwise, execute step S26.

Step S25, discarding the PDU.

In this step, by discarding the received PDU, repeated processing of the same PDU can be avoided, which is beneficial to improve processing efficiency and correct rate.

Step S26, buffering the PDU.

In this step, by buffering the received PDU, it is possible to avoid wrongly discarding the data originally transmitted by the sender due to misjudgment, avoid data loss, and improve data transmission quality.

Optionally, when the data in the PDU received by the receiver is initially transmitted data, it may be considered that the receiver has received all the data that needs to be retransmitted.

This embodiment may further include step S27: after receiving all PDUs containing retransmitted data, sort the received PDUs containing retransmitted data according to the ascending order of COUNT values, and then submit the PDUs to the upper layer in sequence. Wherein, the counter COUNT of the receiving side is composed of the rollover statistics count HFN and SN, and the COUNT in each PDU is the same as its corresponding SN.

In this embodiment, whether the PDU with retransmission data needs to be discarded is judged by the reordering window and whether the same PDU is currently buffered, which improves the accuracy of the judgment result and avoids the occurrence of data receiver and sender states The phenomenon of discarding normally sent data caused by variable inconsistency improves the reliability of the data transmission process.

As shown in FIG. 3 , another embodiment of the present invention provides a data transmission method, including the following steps.

Step S31 , receiving a protocol data unit PDU, the first identifier in the header information of the PDU indicates that the data in the PDU is not retransmission data.

Step S32, judging according to the first identifier that the data in the received PDU is not retransmission data.

Step S33 , judging whether the initial transmission data in the PDU is the data sent after link reestablishment, if yes, execute step S34 , if not, execute S35 .

Step S34, judging whether the PDU SN is 1 greater than the SN of the PDU submitted to the upper layer last time, if so, then submit the received PDU to the upper layer; otherwise, buffer the received PDU.

Step S35, updating relevant state variables according to the received PDU SN, and submitting the received PDU to the upper layer.

The process can specifically be: when the received PDU SN is less than the next expected received PDU SN, add 1 to the rollover count HFN.

That is to say, when the data in the received PDU is not retransmission data, if it is normally sent and received data, its SN is incremented. Assuming the range of SN is 0-4095, the sender will continue and repeat sending SN to 0 For the data of -4095, every time the data of 0-4095 is sent, the SN rollover statistics count HFN will add 1 to indicate the number of times of data transmission. Suppose the currently received SN is 3, then the next expected received SN should be 4, but if the currently received SN is smaller than the next SN that should be received, for example, the received SN is 2, indicating that the receiver has received the above The data in one transmission process, that is, the data loss phenomenon occurred in the last data transmission, the HFN of the receiver is inconsistent with the sender at this time, which leads to the encryption and decryption of the sender and receiver at the PDCP layer according to The encryption and decryption COUNT parameters calculated by HFN and SN are inconsistent, and cause the receiver to decrypt wrong data, and continue to cause the receiver to fail to decompress.

In order to ensure that in the subsequent data transmission process, the HFN of the receiver and the sender are consistent and ensure the normal transmission of data, in the method provided by this embodiment, when it is judged that the received PDU SN is less than the next expected received PDU SN, it is The receiver's HFN is automatically incremented by 1, thus effectively ensuring the synchronization of the data sender and the receiver's SN rollover count state variable HFN when the number of lost PDUs in the link exceeds the reordering window size, which improves the protocol layer when the user plane is not empty Reliability and stability of high-speed data transmission processing under encryption algorithm encryption and ROHC compression processing conditions.

As shown in FIG. 4, another embodiment of the present invention provides a device, including: a sending unit 41, configured to send a PDU, and the first identifier in the header information of the PDU indicates whether the data in the PDU is Retransmit data. The device provided in this embodiment can be used to implement the steps performed by the sender or the base station in the methods provided in the foregoing embodiments, and details are not repeated here. The device provided in this embodiment may be a base station, or other devices that can send data packets to the UE.

As shown in FIG. 5 , a device provided by another embodiment of the present invention includes: a receiving unit 51, configured to receive a PDU, and the first identifier in the header information of the PDU indicates whether the data in the PDU is Retransmit data.

Optionally, the device further includes: a processing unit 52, configured to: when the data in the PDU is retransmission data and the PDU is a PDU received within the reordering window, and the same PDU has been buffered, or when the When the data in the PDU is retransmission data and the PDU is a PDU received outside the reordering window, the PDU is discarded; or when the PDU is a PDU received in the reordering window and the same PDU is not cached , cache the PDU.

Optionally, the processing unit 52 may include a storage unit 53, and the storage unit 53 caches the PDU.

For example, the working process of each unit in the device is: the receiving unit receives the PDU sent by the data sender, and the processing unit judges whether the data in the PDU is retransmission data according to the first identifier in the header information of the PDU. If the PDU with retransmission data is a PDU received within the reordering window and the same PDU has been buffered, or the PDU with retransmission data is a PDU received outside the reordering window, the received PDU is discarded. When it is determined that the PDU with retransmission data is a PDU received within the reordering window and the same PDU is not buffered, the PDU is buffered.

The device provided in this embodiment can be used to implement the steps performed by the receiver in the method provided in the foregoing embodiments, and details are not repeated here. The device provided in this embodiment may be user equipment UE, such as a mobile phone.

The present invention also provides a data transmission system, the structure of which is shown in Figure 6, comprising: a data sender 61 and a data receiver 62, wherein:

The data sender 61 is used to send a protocol data unit PDU, and the first identifier in the header information of the PDU indicates whether the data in the PDU is retransmission data;

The data receiver 62 is configured to receive the PDU sent by the sender.

Further, the data receiver is also used for, when the data in the PDU is retransmission data and the PDU is a PDU received within the reordering window, and the same PDU has been cached, or when the PDU in the PDU When the data is retransmission data and the PDU is a PDU received outside the reordering window, discard the PDU; or when the PDU is a PDU received within the reordering window and the same PDU is not buffered, cache The PDU.

For the communication process between the data sender 61 and the data receiver 62 in the system provided by this embodiment and other similar processes, reference may be made to the method provided by the above embodiment, and details will not be repeated here.

The device and system provided by the embodiments of the present invention judge whether the data in the PDU is retransmission data through the first identifier in the header information of the PDU, which simplifies the process of judging retransmission data and improves the efficiency of data transmission and reliability, and also save air interface resources. Moreover, judging whether the PDU with retransmitted data needs to be discarded is judged by the reordering window and whether the same PDU is currently cached, which improves the accuracy of the judgment result and avoids the inconsistency of the state variables of the data receiver and the sender. The phenomenon of discarding normally sent data improves the reliability of the data transmission process and improves the working performance of equipment and systems.

Each embodiment in this specification is described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same and similar parts of each embodiment can be referred to each other. As for the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and for the related information, please refer to the description of the method part.

Professionals can further realize that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, computer software or a combination of the two. In order to clearly illustrate the possible For interchangeability, in the above description, the composition and steps of each example have been generally described according to their functions. Whether these functions are executed by hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be regarded as exceeding the scope of the present invention.

The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be directly implemented by hardware, software modules executed by a processor, or a combination of both. Software modules can be placed in random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other Any other known storage medium.

The above description of the disclosed embodiments is provided to enable any person 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 general principles defined herein may be implemented in other embodiments without departing from the scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (9)

1. A data transmission method, characterized in that, comprising: Receiving a protocol data unit PDU, the first identifier in the header information of the PDU indicates whether the data in the PDU is retransmission data; If the first identifier indicates that the data in the PDU is retransmission data, and the PDU is not a PDU received outside the reordering window, and the same PDU as the PDU has been buffered, the PDU is discarded; or, If the first identifier indicates that the data in the PDU is retransmission data, and the PDU is a PDU received outside the reordering window, discarding the PDU; or, If the first identifier indicates that the data in the PDU is retransmission data, the PDU is not a PDU received outside the reordering window, and the same PDU as the PDU is not cached, cache the PDU. 2. The method according to claim 1, further comprising: Obtain the difference between the serial number SN of the PDU and the PDU SN submitted to the upper layer last time; When the difference is greater than the length of the reordering window, the PDU is received outside the reordering window PDUs. 3. The method according to claim 1, further comprising: When the first identifier indicates that the data in the PDU is not retransmission data and is data received after link reconstruction, determine whether the SN of the PDU is 1 greater than the SN of the PDU submitted last time, and if so, then Submit the PDU to the upper layer, otherwise, cache the PDU. 4. The method according to claim 3, wherein the first identifier indicates that the data in the PDU is not retransmitted data, it is data received after non-link reconstruction, and the SN of the PDU is smaller than the following When an SN expects to receive, add 1 to the SN rollover statistics variable HFN, and submit the PDU to the upper layer. 5. A data transmission method, characterized in that, comprising: Send a protocol data unit PDU, the first identifier in the header information of the PDU indicates whether the data in the PDU is retransmission data, so that the PDU receiver performs the following steps after receiving the PDU: The PDU receiver judges whether the data in the PDU is retransmission data according to the first identifier; If the first identifier indicates that the data in the PDU is retransmission data, and the PDU is not a PDU received outside the reordering window, and the same PDU as the PDU has been buffered, the PDU is discarded; or, If the first identifier indicates that the data in the PDU is retransmission data, and the PDU is a PDU received outside the reordering window, discarding the PDU; or, When the first identifier indicates that the data in the PDU is retransmission data, the PDU is not a PDU received outside the reordering window, and the same PDU as the PDU is not cached, cache the PDU. 6. The method of claim 5, wherein, The PDU includes retransmission data, and the first identifier indicates that the data in the PDU is retransmission data; or, The PDU includes initial transmission data, and the first identifier indicates that the data in the PDU is initial transmission data. 7. The method according to claim 5 or 6, characterized in that, When the PDU includes retransmission data, the first flag is 1 or True; or, When the PDU includes initially transmitted data, the first identifier is 0 or False. 8. The method according to claim 7, wherein the PDU is a Packet Convergence Protocol Data Unit (PDCP PDU). 9. A device, characterized in that it comprises: A receiving unit, configured to receive a protocol data unit PDU, the first identifier in the header information of the PDU indicates whether the data in the PDU is retransmission data A processing unit configured to discard the PDU when the first identifier indicates that the data in the PDU is retransmission data, the PDU is not a PDU received outside the reordering window, and the same PDU has been buffered; or , when the first identifier indicates that the data in the PDU is retransmission data, and the PDU is a PDU received outside the reordering window, discarding the PDU; or, when the first identifier indicates that the If the data in the PDU is retransmission data, the PDU is not a PDU received outside the reordering window, and the same PDU is not cached, the PDU is cached.

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