2014 Volume 5 Issue 2 Pages 172-183
Wireless multihop networks can be potentially used to realize a smart community that comprehensively controls social infrastructures. In a wireless multihop transmission, personal data are forwarded by a third party, so wireless security is indispensable. In current wireless systems, security is ensured by encryption in the upper layers. However, this encryption tends to require a complex protocol or processing, which is not suitable for a multihop protocol with a simple implementation. To solve this problem, we have proposed a chaos multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) scheme with physical layer encryption and channel-coding abilities. On the other hand, an effective technique for wireless multihop transmission is point-to-multipoint (P-MP) communication, and recently, multi-user (MU)-MIMO has been proposed as an effective P-MP scheme. In MU-MIMO, wireless security is also important. However, there are few studies considering MU-MIMO security in the physical layer. Therefore, in this paper, we propose a multiuser (MU) chaos MIMO-OFDM scheme that achieves physical layer security and channel-coding gain in MU-MIMO transmission. Additionally, the user distribution and propagation loss are taken into consideration. The improved performances are shown through computer simulations.