Selective updating of compression dictionary

摘要

A telecommunications network comprises a sending entity ( 22 ) and a receiving entity ( 24 ) which communicate over a radio interface ( 26 ). The sending entity ( 22 ) comprises a compressor ( 40 ) and a message formatter ( 34 ). The compressor ( 40 ) in turn comprises a sending entity compression dictionary ( 60 ) and dictionary update decision logic ( 62 ). The compressor ( 40 ) compresses a message to obtain a compressed message to be sent over the radio interface ( 26 ) to the receiving entity ( 24 ) and also determines a compression factor for the message. The compression factor is based on similarity of the message to contents of the sending entity compression dictionary. The dictionary update decision logic ( 62 ) makes a decision whether the compression factor justifies updating of a receiving entity decompression dictionary ( 70 ). The message formatter ( 34 ) includes, in the compressed message, an update indication regarding the decision. The receiving entity ( 24 ) has a decompressor ( 50 ) which comprises the receiving entity decompression dictionary ( 70 ) and decompression dictionary update determination logic ( 72 ). The decompressor ( 50 ) decompresses the compressed message to obtain a decompressed message. The decompression dictionary update determination logic ( 72 ) uses the update indication to ascertain whether to use the decompressed message to update the receiving entity decompression dictionary ( 70 ). In one example illustrative embodiment, the compressor ( 40 ) uses a SigComp compression scheme to compress the message to obtain the compressed message, and the message formatter ( 34 ) sets a bit flag in a SigComp portion of the compressed message as the update indication.