A novel synchronization scheme for relay-assisted cooperative communication systems

This paper presents a novel synchronization scheme for relay-assisted cooperative communication systems. According to the proposed scheme, the source node transmits a self-symmetric preamble. Taking advantage of this structure, the relay nodes carry out simple yet robust timing synchronization in the presence of large carrier frequency offset (CFO). Each relay node multiplies the received preamble by different frequency rotation function before retransmission. The destination node carries out the novel synchronization algorithm in both time domain and frequency domain at the same time. When the preamble from a certain relay arrives, a sharp peak will emerge in the spectrum of the matching sequence. Simulation results show that the proposed scheme provides very good timing synchronization performance in the presence of multiple CFOs, and also provides accurate estimation of multiple CFOs.