A special case of mahler’s conjecture.pdfVIP

Novel Decoding Technique for the Synchronous and Quasi-synchronous Multiple Access Adder Channel G. Markarian P. Benachour B. Honary Lancaster Communications Research Centre SECAMS, Lancaster University, Lancaster, LA1 4YR E-mail : g.markarian@tancaster.ac.uk Abstract A novel technique that allows efficient trellis decoding for the M-choose-T synchronous multiple access (MA) adder channel is investigated. Decoding in the M-choose-T system is performed in two operations, identifying the set of active users in the channel and decoding the received data according to which set of users are active. The results show that a sufficient performance improvement is achieved without the need for additional information regarding the active users. The application of the proposed technique to the quasi-synchronous MA adder channel is also analysed. The modified decoding procedure shows a further improvement when compared to the conventional hard decoding technique. 1. Introduction A MA adder channel is said to be synchronous, if the encoders and the decoder are in block synchronism. If no block synchronism exists between the encoders and the decoder, the system is said to be asynchronous. However, it is quasi-synchronous if the encoders are not in block synchronism with each other, but the decoder knows the block position of each encoder in the received sequence of symbols, and bit synchronism is maintained amongst the encoders and the decoder. In the MA adder channel, the output symbol value is the arithmet