Feedback reduction in OFDMA systems by scheduling probability prediction

In this paper, we propose a new feedback scheme called scheduling probability prediction-based selective feedback (SPP-SF) for channel state feedback in OFDMA downlink system. In the SPP-SF scheme, each user first calculates the scheduling probability of each subchannel (i.e., the probability that the user wins the scheduling competition for the subchannel) and then reports the state of a part of the subchannels whose “scheduling probabilities” are higher than the other subchannels. The conventional selective feedback (SF) scheme which reports a part of the subchannels whose “MCS levels” are higher than the other subchannels may be regarded as a subset of the SPP-SF scheme applicable in statistically identical subchannel environment. Numerical results reveal that the SPP-SF scheme achieves significant performance gain over the conventional SF scheme, especially when the statistical characteristics of different subchannels are non-identical.