Header compression in real time services.

摘要

The invention relates to a method for transferring a data packet from a compressor to a decompressor said data packet including a header with header data fields. A number of the header data fields that remain constant during the data transfer are stored in the decompressor. In a compressed data packet, a header data field that varies is replaced by a compressed value identifying a data packet in a compression sequence. In the decompressor context data comprising information for relating the received compressed value to a corresponding compression sequence is maintained and the information is updated according to the received compressed values. The compressed value and the information of the corresponding compression sequence are used for mapping the compressed value into a decompressed header data field. Thus compressed data is unambiguously mapped to a full packet data header field in the decompressor side throughout the session.