Multi‐layer interleave‐division multiple access: theory and practice

Direct‐sequence code‐division multiple access(DS‐CDMA) is often put on the same level with CDMA, ignoring the fact that many different CDMA techniques exist. A special CDMA technique which has recently become popular isinterleave‐division multiple access(IDMA). In this semi‐tutorial, focus is on a generalisation of IDMA referred to asinterleave‐division multiplexing(IDM)/IDMA ormulti‐layer IDMAfor short. Multi‐layer IDMA is a special form of superposition coding, and can be interpreted as ajoint modulation, channel coding and multiple access scheme. Motivated by information theoretical arguments and practical functionalities, a wide range of subjects (such as capacity bounds, power allocation, receiver analysis, quality of service aspects, multi‐layer ARQ and possible applications) are covered. This semi‐tutorial consists of three parts: in the first part, an introduction to IDMA (Section 1) and multi‐layer IDMA (Section 2) is given. In the second part, practical issues such as functionalities of multi‐layer IDMA (Section 3) and multi‐layer ARQ (Section4) are studied. In the third part, information theoretical bounds in conjunction with power allocation (Section 5) and a receiver analysis (Section 6) are provided, before conclusions are drawn in Section 7.