Efficient random multiple-access using iterative interference cancelation receivers

An asynchronous multi-packet multiple user receiver for ALOHA-type random access is detailed and examined for application in high-density multiple-access satellite systems. Coordination of transmissions is avoided by applying a multi-packet receiver at the satellite hub. This hub receiver differs from the recently standardized Diversity Slotted ALOHA protocols in that it executes traffic separation at the PHY protocol layer via an iterative interference cancelation (IIC) receiver algorithm. While principles of IIC are well established in theory [4], [5], practical examples are rare, and face numerous implementation challenges that need to be overcome. Typical channel impairments, such as as carrier and clock frequency off-sets, as well as channel Doppler effects are investigated. User-specific frequency-domain equalizers as well as accurate reconstruction filters for the mutual signal cancelation are introduced. A software implementation of the receiver is discussed and used to quantify system performance which is compared with theoretical limits.