Theoretical limits of asynchronous multicode DS-CDMA systems over AWGN channels are investigated by computer simulations using the statistics of the associated Shannon capacity. The system capacity is identified with the maximum rate at which an errorless link may operate and is a random quantity depending on the spreading sequences and on the users relative delays and phases. A comparison is reported between chaos-based spreading, possibly complemented by an off-line orthogonalization method and OVSF spreading with a subsequent on-line scrambling in order to address the trade-off between the orthogonality of different (but synchronous) codes of the same user and the auto-correlation properties that counter asynchronous multiple-access interference. We here report that chaos-based strategies result in a non negligible increase in capacity with respect to the classical approach.
Shannon Capacity of Chaos-Based and Conventional Asynchronous Multi-Code DS-CDMA Systems over AWGN Channels
SETTI, Gianluca
2006
Abstract
Theoretical limits of asynchronous multicode DS-CDMA systems over AWGN channels are investigated by computer simulations using the statistics of the associated Shannon capacity. The system capacity is identified with the maximum rate at which an errorless link may operate and is a random quantity depending on the spreading sequences and on the users relative delays and phases. A comparison is reported between chaos-based spreading, possibly complemented by an off-line orthogonalization method and OVSF spreading with a subsequent on-line scrambling in order to address the trade-off between the orthogonality of different (but synchronous) codes of the same user and the auto-correlation properties that counter asynchronous multiple-access interference. We here report that chaos-based strategies result in a non negligible increase in capacity with respect to the classical approach.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.