WO2005109817A1

WO2005109817A1 - A method of transmitting the status report

Info

Publication number: WO2005109817A1
Application number: PCT/CN2005/000603
Authority: WO
Inventors: Xuezhi Yang
Original assignee: Huawei Technologies Co.,Ltd.
Priority date: 2004-05-12
Filing date: 2005-04-29
Publication date: 2005-11-17
Also published as: CN1697556A; CN100512506C

Abstract

A method of transmitting the status report is applied to the communication system including the acknowledgement model AM entity. In which, the process of sending the status report includes: when the current AM entity determines that it need send the status report, and further determines that the RLC SDU which will be encapsulated and sent by current AMD PDU is not the tail data of the RLC SDU, inserts the status report into the AMD PDU, and inserts LI specific value indicating that the RLC SUC data transmission is not over, LI indicating the length of the RLC SDU included in the current AMD PDU and LI particular value indicating that the current AMD PDU is includes the status report, then sends the AMD PDU. The process of receiving the status report includes: when the AM entity has received the AMD PDU, determines to be that the AMD PDU includes the said LI specific value, gets the RLC SDU data and the status report from the current AMD PDU; and continues receiving the succedent part of the RLC SDU. According to the invention, in the case which the RLC SDU transmission is not over, transmits the status report by concatenation.

Description

Method for transmitting status report

Technical field

The present invention relates to information transmission technology, and particularly to a method for transmitting a status report in a confirmation mode in a mobile communication system. Background of the invention

The wireless transmission technology of the Universal Mobile Telecommunications System (UMTS) includes frequency division duplex mode (FDD) and time division duplex mode (TDD). Currently, WCDMA uses the FDD mode, and TD-CDMA and TD-SCDMA use the TDD mode. According to the difference in chip rate, TD-CDMA and TD-SCDMA are also called 3.84McpsTDD and 1.28McpsTDD, respectively. The UMTS system includes radio access network (RAN) and core network (CN) parts. Among them, the RAN is used to process all radio-related functions. The CN is responsible for processing all voice calls and data connections in the UMTS system, and implements external network. Switching and routing functions.

In the UMTS system, the wireless interface protocol is divided into a physical layer, a data link layer, and a network layer. The radio link control (RLC) in the data link layer supports three modes: transparent mode (TM), unacknowledged mode (UM) and acknowledged mode (AM). It implements segmentation, concatenation, padding, error control, and flow control. , Repeatability and other functions. Among them, the AM mode has an automatic request retransmission (ARQ) mechanism, and the RLC AM mode can use a sliding window protocol.

Figure 1 shows the model of the RLC AM entity. Each RLC AM entity includes a sending side and a receiving side. The sending side is used to schedule and send data units, and sends the data units to the peer RLC AM entity. The receiving side is responsible for receiving data. The unit sends to the upper layer, and generates a status report, transmits the reception status of the data unit to the sending side, and sends it to the peer RLC AM entity. The status report is also used for functions such as window control. The specific implementation process is shown in Figure 1, including:

The sending side of the RLC AM entity receives the RLC service data unit (SDU) from the upper layer, Segment / concatenate the received RLC SDU to implement transmission of the RLC SDU into one or more acknowledgment mode data (AMD) PDUs. According to actual needs, the sending side may also perform filling processing; Assemble AMD PDUs and encrypt the assembled AMD PDUs and send them to the sending buffer; the sending buffer in the sending side schedules its own. AMD PDUs are scheduled. If the scheduled PDUs are allowed to be sent, they are based on the rules configured by the higher layer Set the polling bit and piggybacked status protocol data unit (Piggybacked STATUS PDU). If it is a newly assembled AMD PDU, set the sequence number field. Then, submit the scheduled AMD PDU to the underlying AM entity and send it to the peer AM entity.

The receiving side of the RLC AM entity puts the received AMD PDU into the receiving buffer; then decrypts it and parses the decrypted data; and then determines whether the parsed PDU can reassemble the RLC SDU, and if it can reassemble the complete The RLC SDU performs a recombination operation, and submits the recombined RLC SDU to the upper layer. Among them, the RLC control unit, the receiving buffer and the retransmission management module on the receiving side will determine whether the current AMD PDU transmission is accurate and whether it is necessary to return a corresponding status report. If a status report is required, and the status report can be carried by the AMD PDU , The sending side of the AM entity performs the step of setting fields in the RLC header to place the status report in the Piggybacked STATUS PDU, which is piggybacked by the AMD 'PDU to the peer AM entity; if the status report cannot currently be piggybacked through the AMD PDU, it sends The side separately constructs a status protocol data unit (STATUS PDU), and sends a status report to the peer AM entity through the STATUS PDU.

FIG. 2 shows the format of an AMD PDU, where a length indicator (LI, Length Indicator) is used to indicate the number of bytes from the end of the RLC header in the AMD PDU to the last byte of the RLC SDU in the PDU, that is, the data The length of (Data) can also be understood as identifying the end position of the RLC SDU data in the PDU. For AMD PDUs, when the length of the AMD PDU is not greater than 126 bytes, a 7-bit LI is used; otherwise, a 15-bit LI is used. In addition to LI for length indication, some special values are also used to indicate other meanings. Such as As shown below, Table 1 shows the meaning of the special 7-bit LI value, and Table 2 shows the special 15-bit LI value.

Meaning of '.

Bit Description

0000000 The previous RLC PDU is exactly filled with an RLC SDU. There is no LI in the previous RLC PDU to mark the end of the SDU.

1111100 UMD PDU: The first byte of this RLC PDU is an RLC

The first byte of the SDU;

AMD PDU: Reserved (In the current version, PDUs with this value are discarded)

1111101 Reserved (in the current version, PDUs with this value are discarded)

1111110 AMD PDU: The rest of the PDU contains a piggybacked status protocol data unit (Piggybacked STATUS PDU);

UMD PDU: Reserved (In the current version, PDUs with this value are discarded)

The remaining part of the 1111111 RLC PDU is stuffing bits. The length of stuffing bits can be zero.

Table 1

Bit Description

000000000000000 The previous RLC PDU is exactly filled with an RLC SDU. There is no LI in the previous RLC PDU to mark the end of the SDU.

111111111111011 The last segment of the RLC SDU is filled with one byte remaining after the previous RLC PDU. There is no LI in the previous RLC PDU to mark the end of the RLC SDU. The last byte in the previous PDU is ignored.

111111 111 111 100 UMD PDU: The first byte of this RLC PDU is a

The first byte of the RLC SDU;

AMD PDU: Reserved (In the current version, PDUs with this value are discarded)

111111111111101 Reserved (In the current version, PDUs with this value are discarded)

111111111111110 AMD PDU: The rest of the PDU contains a piggybacked status protocol data unit (Piggybacked STATUS PDU);

UMD PDU: Reserved (In the current version, PDUs with this value are discarded)

The remaining part of the 111111111111111 RLC PDU is padding bits, and the length of the padding bits can be zero Table 2

Referring to Figure 2 and Table 1, the following Table 3 is AMD PDU with Piggybacked

The format of the STATUS PDU, where LI = 1111110 is used to indicate that the rest of the PDU contains a Piggybacked STATUS PDU.

RLC header (first byte)-

RLC header (second byte)

LI = bbbbbbb, indicating length indication

LI = 1111110, indicating that the rest of the PDU contains a piggybacked status agreement

Protocol Data Unit Data Piggybacked STATUS PDU _

table 3

It has been explained above that in the RLC protocol of the UMTS system, an AM entity may use a status protocol data unit (STATUS PDU) or a piggybacked status protocol data unit (Piggybacked STATUS PDU) to send a status report to the peer AM entity. At present, when sending a status report, before the current RLC SDU transmission is not completed, only one can be constructed. A separate STATUS PDU is used to transmit the status report. The way of constructing a STATUS PDU introduces a lot of padding bits and occupies bandwidth.

When using Piggybacked STATUS PDU, it is possible to avoid constructing a PDU unit transmission status report separately, thereby avoiding many padding bits to save bandwidth. However, because LI. Is used to indicate the end of an RLC SDU, only after the current SDU ends in an AMD PDU, the Piggybacked STATUS PDU can be cascaded at the tail of the ADM PDU for transmission, that is, in RLC During SDU transmission, if an RLC SDU occupies multiple AMD PDUs, LI can only appear in the last AMD PDU. Piggybacked STATUS PDU can only be placed in the tail of the last AMD PDU to transmit status reports; If the status report is transmitted before the current RLC SDU transmission is not completed, then only The transmission of status reports can be achieved by constructing STATUS PDUs. Summary of the invention

In view of this, the main purpose of the present invention is to provide a status report transmission method, so that when a RLC SDU transmission is not completed, a piggybacked STATUS PDU can be used to transmit the status report, thereby avoiding the construction of a separate STATUS PDU and the introduction of Multiple padding bits save bandwidth.

The technical solution provided by the present invention includes a status report sending process: the current AM entity determines whether a status report needs to be sent, if not, then exits the current process, and if necessary, further determines whether the RLC SDU to be encapsulated and transmitted by the current AMD PDU is described as described above. The tail data of the RLC SDU, if yes, exit the current process; otherwise, insert a status report into the AMD PDU, and insert a special LI value indicating that the RLC SDU data transmission has not ended, indicating the length of the RLC SDU data contained in the current AMD PDU LI, which means that the current AMD PDU contains the LI specific value of the status report, and then sends the AMD PDU out;

The technical solution provided by the present invention further includes a receiving process of the status report: when the AM entity receives the AMD PDU, it determines whether it contains the special LI value, if not, it exits the current process, and if there is, it takes it out of the current AMD PDU. RLC SDU data and status reports; and continue receiving the subsequent parts of the RLC SDU.

Wherein, the status report is carried by piggybacked status protocol data unit Piggybacked STATUS PDU; the LI indicating that the current AMD PDU contains a status report is that the remaining part of the AMD PDU includes a specific value of a piggybacked status protocol data unit .

Wherein, in the AMD PDU, the LI indicating the RLC SDU data length in the current AMD PDU is located behind the LI special value, and the LI specific value is located after the RLC SDU data length LI in the current AMD PDU. The status agreement of the piggybacking The proposed data unit is located after the RLC SDU data in the current AMD PDU.

The special value of LI is a reserved field of LI in the AM mode of the UMTS RLC protocol. When the length of the AMD PDU is not greater than 126 bytes, the LI is 7 bits, otherwise it is 15 bits.

The communication system is a universal mobile communication system UMTS.

From the above, it can be seen that the status report transmission method provided by the present invention can transmit a status report data unit by inserting a piggybacked status protocol data unit after an AMD PDU without transmitting the RLC SDU. And it does not affect the current RLC SDU transmission process, thereby avoiding the separate construction of STATUS PDUs, thereby further avoiding the introduction of many padding bits, saving bandwidth, and improving link transmission efficiency. Brief description of the drawings

Figure 1 is a model diagram of the RLC AM entity.

Figure 2 is a schematic diagram of the AMD PDU format in UMTS.

FIG. 3 is a flowchart of sending a status report according to the present invention.

FIG. 4 is a flowchart of receiving a status report according to the present invention. Mode of Carrying Out the Invention

When the RLC SDU is not transmitted, the present invention inserts a Piggybacked STATUS PDU transmission status report without affecting the transmission of the RLC SDU to avoid constructing a STATUS PDU separately. The implementation method of the present invention is described in detail below.

The present invention uses at least 3 LIs in the LI field of the AMD PDU format. Wherein, a special value of LI is used to indicate that the RLC SDU data transmission in the current AMD PDU is not ended, and this special value is set by the present invention; a LI is used to indicate that the RLC SDU data contained in the current AMD PDU is in the current AMD PDU. Length; and use a LI feature The fixed value indicates that the current AMD PDU contains a Piggybacked STATUS PDU, and the Piggybacked STATUS PDU contains a status ^ ^: report.

When in use, place the set LI special value at the first LI position of the three LIs in the AMD PDU, use the second LI to indicate the data length of the RLC SDU carried by the PDU, and then use the third LI LI means that Piggybacked STATUS PDU is connected at the tail of the PDU. In this way, after receiving the AMD PDU, the receiver, after detecting the first LI special value, knows that the RLC SDU behind the position specified by the second LI in the PDU has not been transmitted and will continue to receive the LC in subsequent AMD PDU SDU data to complete the reception of the RLC SDU; on the other hand, the Piggybacked STATUS PDU is read from the AMD PDU according to the third LI special value to implement the transmission of the status report. The LI special value set above is placed in the first position of the three LIs, but it is not difficult to understand that in this AMD PDU, the set LI special value may also be placed in the second or third position.

From Table 1 and Table 2, it can be shown that among the special values of the current RLC version LI, the 7-bit 1111100 and 1111101, and the 15-bit 111111111111100 and 111111111111101 are reserved fields in the AMD PDU, and can be set to indicate the next The RLC SDU indicated by the LI does not end in this PDU.

In this example, for the Ί-bit and 15-bit LI, setting 1111100 and 111111111111100 respectively indicates that the RLC SDU indicated by the next LI has not ended in the current AMD PDU. The following uses 7-bit LI as an example, and refers to the status report sending process shown in FIG. 2 and FIG. 3 and the status report receiving process shown in FIG. 4. If the current RLC SDU transmission is not completed, the transmission status report is reported. The method is described in detail, including:

Referring to the status report sending flowchart shown in FIG. 3, the current AM entity first determines whether a status report needs to be sent, and if not, exits the current process; otherwise, further determines whether the current RLC SDU to be encapsulated and transmitted by the AMD PDU is the RLC SDU Trailing data, that is, determining whether the RLC SDU transmission is complete, if it is, exit the current process, as shown in Table 3. The outgoing method piggybacks the status report when transmitting the RLC SDU. Otherwise, the method described below is used to construct an AMD PDU carrying the RLC SDU and status report; and then sends the RLC SDU piggybacking the status report.

Wherein, when piggybacking the status report in the present invention, the Piggybacked STATUS PDU is used to carry the status report, and the Piggybacked STATUS PDU is concatenated at the tail of the current AMD PDU, and is set according to the AMD PDU structure shown in Table 4. Among them, the first LI

= 1111100 means: the next RLC SDU indicated by the LI in this AMD PDU does not end in this PDU, which means that the next LI = bbbbbbb does not indicate the end of the RLC SDU transmission; the next LI is the second LI = bbbbbbb is used to Represents the number of bytes occupied by the RLC SDU in the current AMD PDU, or the length of the RLC SDU data in the AMD PDU; the next next LI = 1111110, see the description in Table 1, indicating the current AMD PDU The remaining part contains a cascaded state protocol data unit; the next data is the AMD

PDU-encapsulated RLC SDU data is piggybacked at the end of AMD PDU

STATUS PDU. After the AM entity constructs the PDU, the sending side sends the AMD PDU to the peer AM entity.

RLC header (first byte)

RLC header (second byte)

LI = 1111100, indicating: The next LI indicates that the SDU has no knot in this PDU. F LI-bbbbbbb, indicating the length indication ― LI-1111110, indicating that the remaining part of the PDU contains a cascaded state protocol data unit data piggybacked state protocol data. Unit (Piggybacked STATUS PDU)

Table 4

Referring to the status report receiving flowchart shown in FIG. 4, after receiving the AMD PDU by the receiving side of the opposite AM entity, the receiving side judges the encapsulation through LI = 1111100 and the second LI = bbbbbbb And read out the RLC SDU data, and know that the RLC SDU data in the subsequent AMD PDU still belongs to the current RLC SDU, and will continue to receive the subsequent parts of the current RLC SDU to complete the reception and reorganization of the RLC SDU. On the other hand, the receiving side learns the position of the Piggybacked STATUS PDU in the AMD. PDU according to LI = bbbbbbb and LI = 1111110, thereby reading the Piggybacked STATUS PDU and completing the transmission of the status report.

When the RLC SDU transmission is not completed, if the status report needs to be transmitted, the AMD PDU structure transmission status report shown in Table 4 is used. If the status report is not required to be transmitted, the subsequent RLC SDU data is transmitted using the AMD PDU structure provided by the existing technology, as shown in the following table. Table 5 is a subsequent PDU containing SDU data, and Table 6 is a SDU tail data. PDU. The RLC SDU data in the AMD PDUs shown in Table 5, Table 6 and Table 4 belong to one RLC SDIL

RLC header (first byte)

RLC header (second byte) Data Table 5

The data contained in the AMD PDU shown in Table 5 is part of the data of the RLC SDU that has not been transmitted. There is no LI byte in this AMD PDU, which means that the data of the subsequent part of the RLC SDU will continue to be transmitted in the subsequent AMD PDU.

RLC header (first byte)

RLC header (second byte)

LI = bbbbbbb, indicating length indication

LI = 1111111, indicating that the remainder is padding data Table 6

In the AMD PDU shown in Table 6, the RLC SDU ends in the PDU, that is, the data in the AMD PDU is the tail data of the RLC SDU. The first LI = bbbbbbb indicates the byte length of the RLC SDU in the current PDU, that is, the end position, and also indicates the end of the RLC SDU transmission; the second LI = 1111111 indicates that the remaining part of the AMD PDU is stuffing bits.

The opposite AM entity continues to receive the AMD PDUs shown in Tables 5 and 6 according to the existing method, reassembles the RLC SDUs in these AMD PDUs, and transmits them to the upper layer to complete the RLC SDU transmission.

It can be seen that during the RLC SDU transmission process, the Piggybacked STATUS PDU transmission status report is inserted during the RLC SDU transmission process, thereby avoiding the construction of a status protocol data unit separately for the transmission of the status report, thereby avoiding the introduction of padding bits, saving This increases bandwidth and improves link transmission efficiency.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall be included in the present invention. Within the scope of protection.

Claims

Claim

1. A method for transmitting a status report, which is applicable to a communication system including an AM entity in an acknowledgement mode. The method includes a sending process of a status report and a receiving process of the status report, and is characterized in that:

The sending process of the status report includes:

The current AM entity determines whether it is necessary to send a status report, and if not, exits the current process, and if necessary, further determines whether the RLC SDU to be encapsulated and transmitted by the current AMD PDU is the tail data of the RLC SDU, and if so, exits the current process, Otherwise, insert a status report into the AMD PDU, and insert a LI special value indicating that the RLC SDU data transmission is not completed, a LI indicating a length of the RLC SDU data in the current AMD PDU, and a LI specific value indicating that the current AMD PDU contains a status report. And then send the AMD PDU. Send it out;

The receiving process of the status report includes:

When the AM entity receives the AMD PDU, it determines whether it contains the special LI value. If not, it exits the current process. If there is, it retrieves the RLC SDU data from the current AMD PDU. Data and status report; and continues the RLC. Reception of subsequent parts of the SDU.

2. The method according to claim 1, wherein: the status report is carried by piggybacked status protocol data unit Piggybacked STATUS PDU; the LI indicating that the current AMD PDU contains the status report is the remaining AMD PDU The section contains the specific values of a piggybacked state protocol data unit.

3. The method according to claim 2, wherein in the AMD PDU, the LI indicating the length of the RLC SDU data in the current AMD PDU is located behind the LI special value, and the LI specific value is located Represents the RLC SDU in the current AMD PDU. The data length LI follows; the piggybacked status protocol data unit is located in the current AMD After the RLC SDU data in the PDU.

4. The method according to claim 1 or 3, wherein the special value of LI is a reserved field of LI in the AM mode of the UMTS RLC protocol.

5. The method according to claim 4, characterized in that, when the length of the AMD PDU is not greater than 126 bytes, the LI is 7 bits, otherwise it is 15 bits.

6. The method according to claim 1, wherein the communication system is a universal mobile communication system (UMTS).