Jamming-resilient subcarrier assignment for OFDMA based space-time coded systems

This paper considers highly efficient jamming resilient wireless system design. First, we introduce a collision free frequency hopping (CFFH) system based on the OFDMA framework and an innovative secure subcarrier assignment scheme. The secure subcarrier assignment algorithm is designed to ensure that: (i) Each user hops to a new set of subcarriers in a pseudo-random manner at the beginning of each hopping period; (ii) Different users always transmit on non-overlapping sets of subcarriers, such that malicious users cannot predict or repeat the hopping pattern of the authorized users, and hence cannot launch follower jamming attacks. Second, we enhance the anti-jamming property of CFFH by incorporating the space-time coding (STC) scheme. The enhanced system is referred to as STC-CFFH. Our analysis indicates that STC-CFFH is particularly powerful in eliminating channel distortion and hostile jamming interference, including both random jamming and follower jamming attacks. Simulation examples are provided to illustrate the performance of the proposed schemes.