OFDMA Uplink Frequency Offset Estimation Via Cooperative Relaying
. Orthogonal Frequency-Division Multiple Access (OFDMA), where each user employs a different set of orthogonal sub-carriers, eliminates Multiple Access Interference (MAI) under perfect conditions. However, frequency offsets generate Inter-Carrier Interference (ICI). Although the impact of frequency offset in OFDMA has been widely investigated, these conventional algorithms may perform poorly in fading, especially when the subcarriers allocated to one user are too few, and all these subcarriers are in a deep fade simultaneously. The impact of fading can be alleviated by using cooperative relaying.