EFFECTIVE BYPASS OF ERROR CONTROL DECODER IN A DIGITAL RADIO SYSTEM FOR TESTING OR UPGRADING EXISTING EQUIPMENT

摘要

A digital radio communications system including a suboptional soft decision (e.g., errors and erasures) channel decoder and a speech decoder can be upgraded to effectively bypass the hard decision channel decoder and allow a higher performance soft decision (e.g., maximum likelihood sequence estimate (MLSE)) decoder to be used-- without requiring physical removal or disconnection of the hard decision channel decoder. The new decoder can feed the existing decoder the right choice of received vector r' to force the existing decoder to produce a certain codeword y' and a certain bit error estimate b'. This technique is useful to test new MLSE decoders on existing radios, or to add an MLSE decoder as an upgrade on existing receivers.