User-specific chip-level interleaver design for IDMA systems
User-specific chip-level interleaver design for IDMA systems
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DOI：
10.1049/el:20063770
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发表时间：
2006-02
影响因子：
1.1
通讯作者：
Hao Wu;L. Ping;A. Perotti
中科院分区：
文献类型：
--
作者：
Hao Wu;L. Ping;A. Perotti
Introduction: The multiple access scheme recently studied in [1, 2] relies on interleaving as the only means for user separation, and hence it is referred to as interleave-division multiple-access (IDMA). IDMA not only inherits many advantages from conventional code-division multiple-access (CDMA), such as robustness against fading and mitigation of cross-cell interference, but also allows a very simple chip-by-chip (CBC) iterative multiuser detection (MUD) strategy while achieving impressive performance [1, 2]. In multipath channels, the per-user complexity of the IDMA MUD algorithm [2] is O(L), which is independent of the user number K and linear with the channel tap number L. It is much lower than that of other alternatives, such as O(2) for the maximum a posteriori (MAP)-based method [3] and O(K) for the well-known minimum mean squared error (MMSE) method [4]. In IDMA systems, different interleavers are assigned to different users. In theory, the user-specific interleavers can be generated independently and randomly. If this is the case, the base station (BS) has to use a considerable amount of memory to store these interleavers, which may cause serious concern when the number of users is large. Also, during the initial link setting-up phase, there should be messages passing between the BS and mobile stations (MSs) to inform each other about their interleavers. Extra bandwidth resource will be consumed for this purpose if the interleavers used by the BS and MSs are long and randomly generated. In this Letter, we examine a power-interleaver generation method to alleviate this concern. With this method, the interleaver assignment scheme is simplified and memory cost is greatly reduced without sacrificing performance.
