WO2006056122A1

WO2006056122A1 - A method for rapidly resuming the context of compression and decompression

Info

Publication number: WO2006056122A1
Application number: PCT/CN2005/001824
Authority: WO
Inventors: Zhenghua Tang
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2004-11-26
Filing date: 2005-11-02
Publication date: 2006-06-01
Also published as: CN1780296A; CN1780296B

Abstract

A method for rapidly resuming context of compression and decompression, in order to solve the problem related art that can not rapidly resume the context so as to cause in lower success ratio of decompression when compressor side occurs a great amount of lost packets; the method includes, automatically sending the status indication information of lost packet when the data compression side detects the data packet being lost; said data compression side initializes the context of the compressor again in accordance with said status indication information, and sending a packet carrying the context information to corresponding data decompression side; the data decompression side updates the context of the de-compressor using the context information of said packet, making the context of both compressor side and de-compressor side to synchronize.

Description

一种快速恢复压缩解压缩上下文的方法 A method for quickly recovering compression and decompression context

技术领域 Technical field

本发明涉及通信技术，尤其涉及在 WCDMA ***中恢复压缩解压缩上下文的方法。 The present invention relates to communication technologies, and more particularly to a method of recovering a compressed decompression context in a WCDMA system.

背景技术 Background technique

随着互联网协议 (IP)技术在无线网络上的应用日益增加， IP协议既可以应用于音频 /视频业务，也可以应用于其它的数据业务，如： www浏览，远程登陆（TELNET)和文件传输（FTP)等。 With the increasing use of Internet Protocol (IP) technology on wireless networks, the IP protocol can be applied to both audio/video services and other data services, such as: www browsing, remote login (TELNET) and file transfer. (FTP), etc.

针对无线信道和 IP协议的特点， WCDMA***引入了一种基于 IP的头压缩算法。通过增量编码的方式，在数据传输中只传递子头域的变化部分，这样可以大大增加 WCDMA ***无线资源的利用率。比如，一个传输控制协议 (TCP) (头长度 20字节） + IP (头长度 ²0字节）的数据包，压缩后的头长度只有 4个字节，压缩比达到了 90%。 For the characteristics of wireless channel and IP protocol, WCDMA system introduces an IP-based header compression algorithm. In the incremental coding mode, only the changed part of the sub-header field is transmitted in the data transmission, which can greatly increase the utilization of the wireless resources of the WCDMA system. For example, a packet with Transmission Control Protocol (TCP) (header length 20 bytes) + IP (header length ²⁰ bytes) has a compressed header length of only 4 bytes and a compression ratio of 90%.

3gpp的 25.323协议（PDCP协议）定义了一种对 IP头进行压缩来节省空中接口资源的头压缩算法，该算法采用差分（DELTA) 的编码方法。如图 1所示，其头压缩算法的主要步骤如下： 3gpp's 25.323 protocol (PDCP protocol) defines a header compression algorithm that compresses IP headers to save air interface resources using a differential (DELTA) encoding method. As shown in Figure 1, the main steps of the header compression algorithm are as follows:

(1)建立两个对等实体：压缩器和解压缩器； (1) Establish two peer entities: a compressor and a decompressor;

(2) 首先压缩器发送 BASE包（全头包），携带上下文信息； (2) First, the compressor sends a BASE packet (full header), carrying context information;

(3)压缩器和解压缩器同时维护这个 BASE包； (3) The compressor and the decompressor simultaneously maintain the BASE package;

(4)压缩器对原始数据 N进行压缩处理，消除冗余部分，形成压缩包 N*, 发送到解压缩器； (4) The compressor compresses the original data N, eliminates the redundant part, forms a compressed package N*, and sends it to the decompressor;

( 5 )解压缩器才艮据 BASE包和 N*,增加冗余部分，恢复原始包 N，更新上下文信息； (5) The decompressor adds the redundant part according to the BASE package and N*, restores the original package N, and updates the context information;

( 6 )压缩器和解压缩器之间通过反馈来维护上下文信息的一致性。从头压缩的原理可以看出，解压缩器恢复数据包完全依赖于前一个数据包的上下文信息，丢包将严重影响解压缩的性能；在 WCDMA网络中，无线链路控制（RLC)的确认模式（AM)和按序发送特性可以确保 PDCP 的数据包完全按照发送时的顺序到达对端。只有在 RLC 出现复位，重建和 SDU丟失时， RLC才会主动丟失緩存的数据包，此时可能出现大量连续的丢包，这将导致解压缩成功率急剧下降。为解决这一问题现有技术提供了一些方法来提高解压缩的成功率。 (6) The consistency between the context information is maintained by feedback between the compressor and the decompressor. The principle of de novo compression can be seen that the decompressor recovers the data packet completely depends on the context information of the previous data packet, and the packet loss will seriously affect the decompression performance. In the WCDMA network, the radio link control (RLC) acknowledgement mode The (AM) and Sequential Transmission features ensure that PDCP packets arrive at the peer exactly as they were sent. Reconstruction only occurs in RLC When the SDU is lost, the RLC will actively lose the buffered packets. At this time, a large number of consecutive packet loss may occur, which will result in a sharp drop in the decompression success rate. To solve this problem, the prior art provides methods to improve the success rate of decompression.

一种是"二次算法"：解压缩器在收到一个压缩的数据包后，先根据上一个数据包的上下文信息和压缩包中携带的增量信息进行解压缩，如果解压缩失败，则假定存在丢包，这时将压缩包中的增量信息按步长增加一倍，然后再次尝试进行解压缩。 One is a "secondary algorithm": after receiving a compressed data packet, the decompressor first decompresses according to the context information of the previous data packet and the incremental information carried in the compressed packet. If the decompression fails, Assuming there is a packet loss, the incremental information in the compressed package is doubled in steps and then attempted to decompress again.

虽然 "二次算法"在丢失一个数据包的情况下，通过步长递增的方法能够提高解压缩的成功率，但是当出现连续丢包的时候，如 RLC 出现复位，重建和 SDU丟失， "二次算法"无法恢复这种错误引起的解压缩失败。 Although the "secondary algorithm" can increase the success rate of decompression by increasing the number of packets in the case of losing one packet, when there is continuous packet loss, such as RLC reset, reconstruction and SDU loss, "two The secondary algorithm "cannot recover the decompression failure caused by this error.

另一种方法在处理 TCP报文的时候，解压缩器在解压缩失败后向压缩器发送反馈信息一上下文 ( CONTEXT )报文， CONTEXT报文中包括了解压缩失败的上下文索引信息，压缩器在收到 CONTEXT报文后，根据 4艮文中的上下文索引重新初始化压缩器上下文，并在下一个数据包中发送全头包，使得两端的压缩、解压缩上下文达成同步；在处理用户数据报协议 ( UDP )报文的时候，由于没有 CONTEXT的反馈机制，压缩器为了防止两端上下文出现不一致的现象，会周期性地发送全头包，解压缩器在收到全头包后重新初始化解压缩的上下文，从而保证两端的压缩解压缩上下文达到同步。 In another method, when the TCP packet is processed, the decompressor sends a feedback information (CONTEXT) message to the compressor after the decompression fails, and the CONTEXT message includes the context index information for understanding the compression failure, and the compressor is in the compressor. After receiving the CONTEXT message, the compressor context is reinitialized according to the context index in the message, and the full header packet is sent in the next data packet, so that the compression and decompression contexts of both ends are synchronized; in processing the user datagram protocol (UDP) When the message is received, since there is no feedback mechanism of CONTEXT, the compressor periodically sends the full header packet in order to prevent the inconsistency between the two ends of the context. The decompressor re-initializes the decompressed context after receiving the full header packet. To ensure that the compression and decompression contexts at both ends are synchronized.

虽然 CONTEXT反馈机制和周期刷新在一定程度上可以恢复压缩解压缩上下文，但存在以下不足： Although the CONTEXT feedback mechanism and periodic refresh can restore the compression and decompression context to a certain extent, the following disadvantages exist:

1、解压缩器只有在解压缩失败后才会向压缩器发送 CONTEXT反馈信息，这样在压缩器收到 CONTEXT报文之前发送的压缩包都会在解压缩器丟失，从而影响解压缩的成功率； 1. The decompressor sends CONTEXT feedback information to the compressor only after the decompression fails, so that the compressed packet sent before the compressor receives the CONTEXT message will be lost in the decompressor, thereby affecting the success rate of decompression;

2、由于 CONTEXT报文属于带内信令，如果带内信令过于频繁，将会占据大量的空中接口资源，严重影响空口资源的利用率。 2. Since the CONTEXT message belongs to in-band signaling, if the in-band signaling is too frequent, it will occupy a large amount of air interface resources, which seriously affects the utilization of air interface resources.

3、对于用户数据报协议（UDP )连接，虽然周期性的发送全头包可以一定程度上防止两端上下文出现不一致的现象。但如果发送全头包过于频繁，压缩效率将降低；另外，如果全头包周期过大，一旦出现解压缩错误，在比较长的时间内也无法恢复。 3. For the User Datagram Protocol (UDP) connection, although the periodic transmission of the full header packet can prevent the inconsistency of the context at both ends to a certain extent. However, if the full header packet is sent too frequently, the compression efficiency will decrease; in addition, if the full header period is too large, once the decompression error occurs Mistakes can't be recovered in a long time.

发明内容 Summary of the invention

本发明提供一种快速恢复压缩解压缩上下文的方法，以解决在压缩器端出现大量丟包时，使用现有技术无法快速恢复上下文，从而导致解压缩成功率较低的问题。 The present invention provides a method for quickly recovering a compression and decompression context, so as to solve the problem that when a large number of packet loss occurs on the compressor side, the existing technology cannot quickly recover the context, resulting in a low success rate of decompression.

一种快速恢复压缩解压缩上下文的方法，包括： A method for quickly recovering a compression and decompression context, including:

A、数据压缩端检测到数据包丟失时重新初始化压缩器的上下文，并向对应的数据解压缩端发送一个携带上下文信息的数据包；使压缩器和解压缩器两端的上下文同步。 A. The data compression end re-initializes the context of the compressor when the data packet is lost, and sends a data packet carrying the context information to the corresponding data decompressing end; synchronizes the context between the compressor and the decompressor.

其中： among them:

由数据压缩端的无线链路控制（RLC )层进行数据包丟失检测。所述数据包丢失为无线链路控制（RLC )复位、重建或服务数据单元 ( SDU )丟失时出现的数据包丟失。 Packet loss detection is performed by the Radio Link Control (RLC) layer of the data compression side. The packet loss is a packet loss that occurs when Radio Link Control (RLC) reset, rebuild, or Service Data Unit (SDU) is lost.

由检测到数据丢失的 RCL层将状态指示信息发送给本端网络层；由本端网络层向本端的分组数据协议（PDCP )层发送重新初始化压缩器的上下文的配置消息，和由该 PDCP层根据所述配置消息初始化本端压缩器的上下文。 The RCL layer that detects the data loss sends the status indication information to the local network layer; the local network layer sends a configuration message re-initializing the context of the compressor to the local packet data protocol (PDCP) layer, and is configured by the PDCP layer. The configuration message initializes the context of the local compressor.

由检测到数据丟失的所述 RLC层将状态指示信息发送给本端 PDCP 层；由该 PDCP层^^据该状态指示信息重新初始化本端压缩器的上下。 The RLC layer that detects the data loss sends the status indication information to the local PDCP layer; and the PDCP layer reinitializes the upper and lower sides of the local compressor according to the status indication information.

而且，通过内部信令传送本端的信息。 Moreover, the information of the local end is transmitted through internal signaling.

所述数据解压缩端收到所述携带上下文的数据包后，由本端的 RLC 向数据压缩端的 PDCP发送确认信息，数据压缩端的 PDCP收到该确认信息后确定上下文同步过程完成。 After receiving the data packet carrying the context, the data decompressing end sends the acknowledgement information to the PDCP of the data compression end by the RLC of the local end, and the PDCP of the data compression end receives the acknowledgement information, and determines that the context synchronization process is completed.

如果数据压缩端的在预定时间内未收到数据解压缩端对所述携带上下文的数据包的确认消息，则重新发送该携带上下文的数据包。 If the data compression end does not receive the acknowledgment message from the data decompressing end to the data packet carrying the context within a predetermined time, the data packet carrying the context is resent.

所述携带上下文信息的数据包为全头包。 The data packet carrying the context information is a full header package.

本发明在出现 RLC复位、重建或 SDU丟失情况时，由数据压缩端的 RLC主动发送状态指示信息来使本端的 PDCP更新压缩器上下文，并主动向解压缩端发送全头包，由解压缩端更新解压缩器的上下文，因而能够快速恢复压缩解压缩上下文的同步，可避免大量连续丢包，从而提高了解压缩成功率。 When the RLC reset, re-establishment or SDU loss occurs, the RLC of the data compression end actively sends the status indication information to enable the local PDCP to update the compressor context and actively The full header packet is sent to the decompressing end, and the decompressor updates the context of the decompressor, so that the synchronization of the compressed decompression context can be quickly restored, and a large number of consecutive packet loss can be avoided, thereby improving the compression success rate.

附图说明 DRAWINGS

图 1为 IP头压缩原理示意图； Figure 1 is a schematic diagram of the IP header compression principle;

图 2为网络和终端之间的逻辑关系示意图； 2 is a schematic diagram of a logical relationship between a network and a terminal;

图 3、图 4为本发明的流程图。 3 and 4 are flowcharts of the present invention.

具体实施方式 detailed description

参阅图 2, 先以网络 UTRAN和终端 UE为例说明压缩器和解压缩器的逻辑关系。 RRC ( Radio Resource Controller, 无线资源控制器）协议层即网络层（L3 ), 它主要负责配置数据链路层的各个单元（本发明主要涉及 PDCP层和 RLC协议层）；分组数据协议（ PDCP )层和无线链路控制 ( RLC )层是数据链路层 ( L2 )的两个协议层，数据业务的传输主要由这两个协议层完成。 PDCP层主要完成数据的压缩解压缩，而 RLC层主要完成数据的传输和与对端的数据确认（即确认发送的数据对端是否已经收到），因此，对于数据压缩端（发送数据端）的 RLC层能检测到数据包是否丟失。 Referring to Figure 2, the network UTRAN and the terminal UE are taken as an example to illustrate the logical relationship between the compressor and the decompressor. The RRC (Radio Resource Controller) protocol layer is the network layer (L3), which is mainly responsible for configuring each unit of the data link layer (the present invention mainly relates to the PDCP layer and the RLC protocol layer); Packet Data Protocol (PDCP) The Layer and Radio Link Control (RLC) layer is the two protocol layers of the Data Link Layer (L2), and the transmission of data services is mainly performed by these two protocol layers. The PDCP layer mainly performs compression and decompression of data, and the RLC layer mainly completes data transmission and data confirmation with the peer end (ie, confirms whether the transmitted data peer has received), and therefore, for the data compression end (sending data end) The RLC layer can detect if a packet is lost.

图 2中以一个双向业务为例（图中两个 PDCP层之间的箭头表示数据流向）：一个双向业务既存在下行数据（即 UTRAN发给 UE数据），也存在上行数据即（即 UE发给 UTRAN数据）。因此在一个 PDCP层中，既包括一个压缩器，也包括一个解压缩器，它们分别完成下行数据的压缩和上行数据的解压缩。对于下行数据， UTRAN的 PDCP层的压缩器经过压缩后发送给 RLC层， RLC层再经过底层的传输发送到 UE的 RLC层， UE 的 RLC层递交给 UE的 PDCP层的解压缩器，解压缩器完成解压缩操作后递交给上层。反之，对于上行数据的传输也是如此。 In Figure 2, a two-way service is taken as an example (the arrow between the two PDCP layers indicates the data flow direction): a two-way service has both downlink data (that is, UTRAN sends data to the UE), and there is also uplink data (that is, the UE sends Give UTRAN data). Therefore, in a PDCP layer, both a compressor and a decompressor are provided, which respectively perform compression of downlink data and decompression of uplink data. For the downlink data, the compressor of the PDCP layer of the UTRAN is compressed and sent to the RLC layer, and the RLC layer is transmitted to the RLC layer of the UE through the underlying transmission, and the RLC layer of the UE is delivered to the decompressor of the PDCP layer of the UE, and decompressed. After the decompression operation is completed, it is delivered to the upper layer. Conversely, the same is true for the transmission of upstream data.

上下文信息是压缩器和解压缩器维护的一些状态信息。它和每一个数据包相关。从上面的描述可以看出，如果 UTRAN的压缩器和 UE的解压缩器能够很好的协作工作，两者必须维护相同的上下文信息。如果 UTRAN 出现了丢包，那么 UTRAN的压缩器维护的上下文信息和 UE的解压缩器维护的上下文信息出现了不一致，这样将导致解压缩失败而引起数据丢失。 Context information is some state information maintained by the compressor and decompressor. It is associated with every packet. As can be seen from the above description, if the compressor of the UTRAN and the decompressor of the UE work well together, both must maintain the same context information. If UTRAN has packet loss, then UTRAN's compressor maintains context information and the UE's decompressor There is an inconsistency in the context information maintained, which will cause the decompression to fail and cause data loss.

本发明为了在出现丢包，尤其是在无线链路控制（RLC ) 出现复位、重建或服务数据单元（SDU )丟失出现大量丟包的时候，能够尽快使压缩器的上下文和对应的解压缩器的上下文达到一致，由检测到数据丢失的 RLC层（如 UTRAN的 RLC层）通过内部信令主动通知本端的 RRC层或者是 PDCP层，然后由 RRC层或者是 PDCP层通知压缩器重新发送一个携带上下文信息的数据包，使得数据压缩端维护的上下文信息和对端（数据解压缩端）的维护的上下文信息重新恢复一致。 The present invention enables the context of the compressor and the corresponding decompressor as soon as possible in the event of packet loss, especially when there is a large number of drops in the reset, re-establishment or loss of service data unit (SDU) of the radio link control (RLC). The context is consistent. The RLC layer (such as the RLC layer of the UTRAN) that detects the data loss actively informs the RRC layer or the PDCP layer of the local end through internal signaling, and then the RRC layer or the PDCP layer notifies the compressor to resend a carry. The data packet of the context information is such that the context information maintained by the data compression end and the context information maintained by the peer end (the data decompressing end) are restored.

无线链路控制层（ RLC )层支持 AM (确认模式）、 UM (非确认模式）和 TM (透明模式）三种工作模式，主要完成数据传输、流量控制、加解密等功能。由于数据业务的 QoS—般要求保证数据的可靠性，因此在数据业务中通常使用 RLC的 AM模式，在 AM模式下，发送方的 RLC收到来自上层协议栈的 PDU (上层的 PDU对应于 RLC层的 SDU )后，首先根据配置的 RLC PDU大小进行分段级联，然后添加 RLC协议头组装成完整的 RLC PDU, 最后完成加密等操作后发送给下层协议栈；接收方的 RLC收到来自下层协议栈的 SDU (下层的 SDU对应于 RLC层的 PDU ) 后，首先进行解密等操作，然后结合当前状态信息和 RLC PDU中的轮循标志判断是否需要向发送方发送状态报告，最后将 PDU 重组成完整的 RLC SDU后提交给上层协议栈。 The Radio Link Control Layer (RLC) layer supports AM (acknowledgement mode), UM (unconfirmed mode), and TM (transparent mode) modes of operation, mainly for data transmission, flow control, and encryption. Since the QoS of the data service generally requires the reliability of the data, the AM mode of the RLC is usually used in the data service. In the AM mode, the RLC of the sender receives the PDU from the upper protocol stack (the upper layer PDU corresponds to the RLC) After the SDU of the layer, the segmentation cascade is first performed according to the configured RLC PDU size, and then the RLC protocol header is added to assemble a complete RLC PDU, and finally the encryption operation is performed, and then sent to the lower layer protocol stack; the RLC of the receiver is received from the receiver. After the SDU of the lower layer protocol stack (the lower layer SDU corresponds to the PDU of the RLC layer), the operation is first performed, and then the current status information and the round robin flag in the RLC PDU are used to determine whether a status report needs to be sent to the sender, and finally the PDU is sent. Recompose the complete RLC SDU and submit it to the upper protocol stack.

当发送方的 RLC接收到来自接收方 RLC的状态报告后，根据状态报告中的信息确定接收方 RLC是否正确接收了发送方 RLC发送的 PDU,如果接收方 RLC没有正确接收，发送方 RLC重新发送该 PDU,如果该 PDU 在发送方经过多次重发后都没有被接收方正确接收，则可能存在底层链路故障或双方协议参数不一致，此时发送方 RLC会主动发起 RESET过程，从而导致数据包丢失。另外在 RLC实体重建和 RLC丟弃的时候也会出现数据包丢失。 After the RLC of the sender receives the status report from the receiver RLC, it determines whether the receiver RLC correctly receives the PDU sent by the sender RLC according to the information in the status report. If the receiver RLC does not receive correctly, the sender RLC resends. The PDU, if the PDU is not correctly received by the receiver after multiple retransmissions by the sender, the underlying link may be faulty or the parameters of the two protocols are inconsistent. At this time, the sender RLC will initiate the RESET process, resulting in data. The package is missing. In addition, packet loss occurs when RLC entity rebuild and RLC discard.

在 UM和 TM模式，发送方 RLC和接收方 RLC之间没有上面描述的确认过程，因此发送方 RLC无法判断发送的 PDU是否被接收方 RLC正确接收，但是当 RLC重建或 RLC丟弃的时候还是可以知道数据包发生了丢失。 In the UM and TM modes, there is no acknowledgement procedure described above between the sender RLC and the receiver RLC, so the sender RLC cannot determine whether the transmitted PDU is being received by the receiver RLC. Accepted, but when the RLC is re-established or the RLC is dropped, it is still known that the packet has been lost.

因此， RLC在 AM模式下可以获取到任何情况下的数据包丢失； UM 模式下可以获取部分情况下的数据包丢失。 Therefore, RLC can obtain packet loss in any case in AM mode; packet loss in some cases can be obtained in UM mode.

参阅图 2、图 3所示，以 UTRAN端向 UE端发送数据，和以 UTRAN 端的 RLC层向本端的网络层（L3 )发送状态指示信息为例，对恢复压缩解压缩上下文的过程说明如下： Referring to FIG. 2 and FIG. 3, the UTRAN end sends data to the UE, and sends the status indication information to the local network layer (L3) by using the RLC layer on the UTRAN side. The process of restoring the compression and decompression context is as follows:

步骤 1、出现 RLC复位或重建，或者业务数据单元（SDU )丢失， UTRAN端（数据压缩端）的 RLC检测到大量数据包丢失。 Step 1. RLC reset or re-establishment occurs, or the service data unit (SDU) is lost, and the RLC of the UTRAN end (data compression end) detects a large amount of data packet loss.

步驟 2、 UTRA的 RLC层主动向本端的网络层 ( L3 )上报一条状态指示信息，表示此时出现了大量数据包丟失。 Step 2: The RLC layer of the UTRA actively reports a status indication message to the local network layer (L3), indicating that a large amount of packet loss occurs at this time.

步骤 3、网络层（L3 )在收到 RLC层上报的状态指示信息后，向本端的分组数据汇聚协议 ( PDCP )层发送一条配置信息，配置信息中的 R/I/C 信元设置为 R, 即要求 PDCP层重新初始化压缩器上下文。 Step 3: After receiving the status indication information reported by the RLC layer, the network layer (L3) sends a configuration information to the local packet data convergence protocol (PDCP) layer, and the R/I/C cell in the configuration information is set to R. , that is, the PDCP layer is required to reinitialize the compressor context.

步驟 4、 UTRAN的 PDCP层在收到配置信息后，如果 R/I/C信元设置为 R, 则初始化压缩器上下文，并在发送给 UE端的下一个数据包中携带上下文信息（即全头包）。 Step 4: After receiving the configuration information, the PDCP layer of the UTRAN initializes the compressor context if the R/I/C cell is set to R, and carries the context information in the next data packet sent to the UE (ie, the full header package).

步骤 5、 UE端的分组数据汇聚协议 ( PDCP )层收到携带上下文信息的数据包后，更新解压缩器上下文，使得压缩器和解压缩器两端的上下文达到同步；同时，由 RLC向 UTRAN端发送确认信息， UTRAN的 PDCP 层收到 RLC对这个全头包的确认信息后，认为上下文同步过程完成。 Step 5: After receiving the data packet carrying the context information, the Packet Data Convergence Protocol (PDCP) layer of the UE end updates the decompressor context, so that the contexts at both ends of the compressor and the decompressor are synchronized; meanwhile, the RLC sends an acknowledgement to the UTRAN end. After the RPRAN layer of the UTRAN receives the confirmation message from the RLC to the full header packet, it considers that the context synchronization process is completed.

如果 URTAN端在预定时间内没有收到 UE端接收全头包的确认消息，则重新发送。 If the URTAN terminal does not receive the acknowledgment message that the UE receives the full header packet within the predetermined time, it resends.

参阅图 2、图 4所示，以 UTRAN端向 UE端发送数据，和以 UTRAN 端的 RLC层向本端的 PDCP层发送状态指示信息为例，对恢复压缩解压缩上下文的过程说明如下： Referring to FIG. 2 and FIG. 4, the UTRAN end sends data to the UE, and sends the status indication information to the PDCP layer of the local end by using the RLC layer on the UTRAN side as an example. The process of restoring the compressed decompression context is as follows:

步骤 10、出现 RLC复位或重建，或者业务数据单元（SDU )丢失， UTRAN端（数据压缩端）的 RLC层检测到大量数据包丟失。 Step 10: RLC reset or reconstruction occurs, or the service data unit (SDU) is lost, and the RLC layer of the UTRAN end (data compression end) detects a large amount of data packet loss.

步骤 11、 UTRA 的 RLC层通过与 PDCP层之间的接口，主动向该端的 PDCP层发送一条状态指示信息，表示此时出现了大量数据包丢失。步骤 12、 UTRAN的 PDCP层在收到状态指示信息后，初始化压缩器上下文，并在发送给 UE的下一个数据包中携带上下文信息（即全头包）。 Step 11. The RLC layer of the UTRA actively forwards to the end through an interface with the PDCP layer. The PDCP layer sends a status indication message indicating that a large amount of packet loss has occurred at this time. Step 12: After receiving the status indication information, the PDCP layer of the UTRAN initializes the compressor context and carries the context information (ie, the full header packet) in the next data packet sent to the UE.

步骤 13、 UE的 PDCP层收到携带上下文信息的数据包后，更新解压缩器上下文，使得本端解压缩器和 URTAN端的压缩器的上下文达到同步；同时， UE的 RLC层向 UTRAN端发送确认信息， UTRAN的 PDCP层收到这个全头包的确认信息后，认为上下文同步过程完成。如果 URTAN端在预定时间内没有收到 UE端接收全头包的确认消息 , 则重新发送。 Step 13: After receiving the data packet carrying the context information, the PDCP layer of the UE updates the decompressor context, so that the context of the local decompressor and the compressor of the URTAN end is synchronized; meanwhile, the RLC layer of the UE sends an acknowledgement to the UTRAN end. After the PDCP layer of the UTRAN receives the confirmation message of the full header packet, it considers that the context synchronization process is completed. If the URTAN terminal does not receive the acknowledgment message that the UE receives the full header packet within the predetermined time, it resends.

对于 UE端向 UTRAN端发送数据时， UE端的 RLC层检测到数据包丟失的处理与上述过程相同理，不再赘述。 When the UE sends data to the UTRAN, the RLC layer of the UE detects that the packet is lost. The process is the same as the above process, and is not described here.

显然 , 本领域的技术人员可以对本发明进行各种改动和变型而不脱离本发明的精神和范围。这样，倘若对本发明的这些修改和变型属于本发明权利要求及其等同技术的范围之内，则本发明也意图包含这些改动和变型在内。 It is apparent that those skilled in the art can make various modifications and variations to the invention without departing from the spirit and scope of the invention. Therefore, it is intended that the present invention cover the modifications and variations of the invention as claimed.

Claims

权利要求 Rights request

1、一种快速恢复压缩解压缩上下文的方法，其特征在于该方法包括如下步骤： A method for quickly recovering a compression and decompression context, characterized in that the method comprises the following steps:

A、数据压缩端检测到数据包丢失时重新初始化本端压缩器的上下文，并向对应的数据解压缩端发送一个携带上下文信息的数据包； A. The data compression end re-initializes the context of the local compressor when the data packet is lost, and sends a data packet carrying the context information to the corresponding data decompressing end;

B、所述数据解压缩端利用数据包中的上下文更新本端解压縮器的上下文，使压缩器和解压缩器两端的上下文同步。 B. The data decompressing end updates the context of the local decompressor by using the context in the data packet to synchronize the context between the compressor and the decompressor.

2、如权利要求 1 所述的方法，其特征在于，由数据压缩端的无线链路控制（RLC )层进行数据包丢失检测。 2. The method of claim 1 wherein the packet loss detection is performed by a Radio Link Control (RLC) layer of the data compression side.

3、如权利要求 1 所述的方法，其特征在于，所述数据包丢失为无线链路控制（RLC ) 复位、重建或服务数据单元（SDU )丟失时出现的数据包丢失。 3. The method of claim 1, wherein the packet loss is a packet loss that occurs when a radio link control (RLC) reset, reestablishment, or service data unit (SDU) is lost.

4、如权利要求 2所述的方法，其特征在于，由检测到数据丟失的 RCL 层将状态指示信息发送给本端网络层；由本端网络层向本端的分组数据协议（PDCP )层发送重新初始化压缩器的上下文的配置消息，以及由该 PDCP 层才艮据该配置消息初始化本端压缩器的上下文。 The method according to claim 2, wherein the RCL layer that detects the data loss sends the status indication information to the local network layer; and the local network layer sends the packet data protocol (PDCP) layer to the local end. A configuration message that initializes the context of the compressor, and the context in which the PDCP layer initializes the local compressor based on the configuration message.

5、如权利要求 2所述的方法，其特征在于，由检测到数据丟失的 RLC 层将状态指示信息发送给本端 PDCP层；由该 PDCP层根据该状态指示信息重新初始化本端压缩器的上下文。 The method according to claim 2, wherein the RLC layer that detects the data loss sends the status indication information to the local PDCP layer; and the PDCP layer reinitializes the local compressor according to the status indication information. Context.

6、如权利要求 4或 5任一项权利要求所述的方法，其特征在于，通过内部信令传送本端的信息。 The method according to any one of claims 4 or 5, characterized in that the information of the local end is transmitted by internal signaling.

7、如权利要求 1至 5任一项所述的方法，其特征在于，所述数据解压缩端收到所述携带上下文的数据包后，由本端的 RLC 向数据压缩端的 PDCP发送确认信息，数据压缩端的 PDCP收到该确认信息后确定上下文同步过程完成。 The method according to any one of claims 1 to 5, wherein after the data decompressing end receives the data packet carrying the context, the RLC of the local end sends an acknowledgement information to the PDCP of the data compression end, and the data is sent. After receiving the confirmation message, the PDCP on the compression side determines that the context synchronization process is completed.

8、如权利要求 7所述的方法，其特征在于，如果数据压缩端的在预定时间内未收到数据解压缩端对所述携带上下文的数据包的确认消息，则重新发送该携带上下文的数据包。 The method according to claim 7, wherein if the data compression end does not receive the acknowledgement message of the data packet carrying the context by the data decompressing terminal within a predetermined time, retransmit the data carrying the context. package.

9、如权利要求 1 所述的方法，其特征在于，所述携带上下文信息的数据包为全头包。 9. The method according to claim 1, wherein the data packet carrying the context information is a full header packet.