Opportunistic scheduling for wireless network coding on two-user OFDMA systems

Opportunistic scheduling for wireless network coding (OWNC) combines the strategies of opportunistic scheduling and network coding. This paper applies two variants of OWNC on a two-user OFDMA system. Symbol-based OWNC decides a strategy from sum rate of the whole OFDM symbol. Subcarrier-based OWNC decides a strategy from the capacity on a subcarrier level. Novel algorithms are derived for power allocation on an OFDM symbol. They appear in the form of waterfilling algorithms but are specifically tailored to the OWNC. Simulation results show average capacity and outage capacity obtained by different approaches of the OWNC. It is shown that, for OWNC with two-user OFDMA, the proposed waterfilling power allocations have modest gains over uniform power allocation at low SNR.