Lattice decoding for joint detection in direct-sequence CDMA systems
A new joint detection method based on sphere packing lattice decoding is presented in this paper. The algorithm is suitable for both synchronous and asynchronous multiple access direct-sequence code-division multiple-access (DS-CDMA) systems, and it may jointly detect up to 64 users with a reasonable complexity. The detection complexity is independent of the modulation size and large M-PAM or M-QAM constellations can be used. Furthermore, a theoretical gain analysis is performed in which the multiple-access system performance is derived from the lattice parameters.
Various peer-to-peer (P2P) architectures for ad-hoc networks have been proposed over the last few years. Most of them are unstructured and use some form of flooding to locate content, because the physical constraints of the underlying network make the construction of arbitrary application-layer overlays impractical. In this paper, we study the problem of applying distributed hash tables (DHT) for mobile ad-hoc networks. Our approach to efficiently lookup content in such networks exploits physical proximity of peers when establishing and maintaining the DHT based routing tables. The efficiency of our method is demonstrated by simulation of large networks.