Wireless physical layer security model and resource allocation algorithm in MISO-OFDMA

The problem of wireless security for the downlink of multiuser MISO-OFDMA systems operating over a frequency-selective channel is investigated. Considering interference suppression and resource allocation between different users, a physical-layer security model is proposed that exploits the redundancy of transmit antenna arrays to provide security by deliberate signal randomisation. Signal randomisation causes the receiver´s signal to have lower power efficiency than the optimal transmit beamforming. To overcome this problem, a suboptimal, but efficient resource allocation algorithm based on spatial correlation and array redundancy is devised.