In this project we investigate the design and performance of advanced digital receivers for use in multiple access communications networks, where a potentially large number of simultaneous users share a common transmission environment. The receivers we study apply iterative soft information processing, which has proven very effective and efficient in the decoding of so-called "turbo" codes. Our receivers integrate error control decoding and multiple access interference resolution to achieve maximum performance. We study the fundamental theoretical limits of various multiple access strategies, including code-division multiple access (CDMA), and design receivers aimed at approaching these limits as closely as possible under a given computational complexity constraint. The theoretical as well as the implementation complexity of these receivers is studied carefully, and hardware implementations are proposed and evaluated. The goal is to design and verify efficient joint receivers for multiple access systems. We also study the interaction of the proposed receivers with higher level communication protocol layers, particularly the operation of these receivers in packet oriented networks with their unique requirements
