Orthogonal frequency division multiple access with an aggregated sub-channel structure and statistical channel quality measurement

In this paper, an orthogonal frequency division multiple access (OFDMA) is considered for the mobile air interface. To reduce the reverse link overheads for CQI feedback, we consider an aggregated sub-channel structure, where a set of adjacent sub-carriers are tied up to a sub-channel to be used as a unit of user-multiplexing and the corresponding power/rate allocation. Modeling the SNR distribution over the bandwidth of a sub-channel as Rician, the channel quality of a sub-channel is summarized with the mean and variance of channel gain envelop divided by noise standard deviation. Then, we develop a generalized two step channel/resource allocation algorithm, which uses the two statistical measurements, and analyze the spectral efficiency of the OFDMA system in terms of average frequency utilization.