Research on a New Model and Network Coding Algorithm for Orthogonal Frequency Division Multiplexing System

The paper studies a new model and network coding algorithm for orthogonal frequency division multiplexing (OFDM) system. Cooperation diversity consists on using relay nodes to combat the effects of fading channels by means of spatial diversity. Physical-layer network coding is used to make the two-way s relay network achieving higher bandwidth efficiency than the traditional four-phase and three-phase bidirectional relaying schemes. Analogy Network Coding (ANC) has been already applied to OFDM for broadband wireless communications. In order to achieve high order of spatial diversity to combat fading, multi-antenna relay can be deployed. However, as the multiple antennas are geographically co-located, the received signals on each individual antenna may experience dependent fading. An alternative spatial diversity approach is through multi-relay cooperation, which poses other design challenges, e.g., synchronization, if all the relays participate in the transmission. As a result, Relay Selection has been proposed to achieve full diversity through a multi-relay network at a lower implementation cost.