Communications system handoff operation combining turbo coding and soft handoff techniques

Communication systems, including, for example, cell-based mobile communication systems, multiple satellite communication systems, or multibeam satellite systems, require reliable handoff methods between cell-to-cell, beam-to-beam, or satellite-to-satellite respectively. Recent measurement of a CDMA cellular system indicates that the system is in handoff about 30% to 50% of an average call period. Therefore, system reliability during handoff is one of the major system performance parameters and eventually becomes a factor in the overall system capacity. The present invention advantageously relates to novel and improved techniques for handoff in cellular communications, multibeam and multisatellite systems. The present invention combines the soft handoff mechanism wvith a code diversity combining technique (i.e., combining signals from multiple sources), a packet combining technique (i.e., combining multiple signals), and an iterative decoding algorithm (e.g., Turbo Coding).