Method and device for reusing context in robustness header compression

Abstract

Provided are a method and a device for reusing a context in a robust header compression, comprising: a method and device for reusing a context by a compression side and a method and device for reusing a context by a decompression side. The method for reusing a context by a compressor includes: finding out, via the compressor after receiving a packet to be compressed, the compression context which has not been used for the longest time in currently existing compression contexts, if a corresponding compression context is not found and there is not enough context identifier (CID) space to create a new compression context; reusing the compression context which has not been used for the longest time to generate a compression context for the packet to be compressed; and packaging the packet to be compressed as an initialization and refresh IR packet carrying a reuse identifier, then sending the same to the decompressor. The decompressor side determines that the received IR packet is an IR packet of a reused context by way of the reuse identifier; the reuse of context will no longer be restricted by the context mode, thus full use can be made of limited context resources and compression efficiency can be improved.

Description

technical field [0001] The invention relates to a robust header compression algorithm in the field of mobile communication, and mainly proposes a context reuse method and device. Background technique [0002] Due to the limitation of physical conditions, the wireless link in the mobile communication system has a lower transmission rate and a higher bit error rate than the wired link. In order to effectively utilize limited wireless channel bandwidth resources, a robust header compression technology (RObust Header Compress, hereinafter referred to as ROHC) is introduced. The core of ROHC is to transparently compress and decompress the information in the packet header between directly connected nodes by using the information redundancy between the packets of the service flow. The ROHC technology is described by the RFC3095 document of the IETF (Internet Engineering Task Force), and was revised by the IETF in February 2007, and the revised document is RFC4815. [0003] Contex...

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Problems solved by technology

[0009] However, in the actual application environment, due to the limited CID space that can be used for the negotiation configuration, and the context that has not been used for a long time has not been destroyed, it is impossible to create a new context when the CID space is exhausted.

At this time, context reuse can be carried out according to the method stipulated in the RFC 4815 protocol. The protocol does not describe how to select the context to be reused. The current implementation method is to select the context that has not been used for the longest time for reuse. However, if the selected context to be reused If the context is in R mode, you can only re-select. Such a selection method may lead to two adverse consequences: 1. If all contexts do not meet the requirements, the uncompressed package will be processed directly, and all subsequent data packets of this package flow will also be Such processing greatly reduces the compression efficiency of the packet flow and the newly added packet flow; 2, the context to be reused selected in this way may be the context in use (the packet flow corresponding to the context is not over, there are still follow-up The packets to be compressed in this packet flow are received), resulting in subsequent data packets for the context to be reused must be reused for other contexts according to the process of context reuse, thus forming a vicious circle and seriously affecting the compression efficiency

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