基于CDMA的Ad Hoc网络抗多址干扰分析

Analysis of Anti-MAI for CDMA-Based Ad Hoc Networks

分析了基于CDMA的Ad Hoc网络抗多址干扰及其对网络性能的影响,给出了泊松分布模型下的信干比与节点分布密度、码集互相关的数学表达式,从理论上指出了基于CDMA的Ad Hoc网络在物理层进行多址干扰检测,以及在MAC层完成冲突避免和在扩频选码时寻找异步互相关性良好的码集的必要性,提出了减小多址干扰的若干措施并分析了在完全异步的无线Ad Hoc网络中不能直接采用Walsh码的原因.

Multiple access interference （MAI） analysis for CDMA-based Ad Hoc networks is presented. Relationship between SIR and density of distributed node and normalized code cross-correlation ratio is given under the Poisson distribution model. Theoretically, it is necessary for CDMA-based Ad Hoc networks to detect multiple access interference on the physical layer, to avoid collision on the MAC layer, and to select the code set with less normalized cross-correlation ratio. SINR is analyzed for an Ad Hoc network with a 64 bit Walsh set, and the result shows that the Walsh code cannot be directly used in an Ad Hoc network. Finally, several anti-MAI measures are presented for CDMA-based Ad Hoc networks.