Time-Frequency Spectrum Sharing Scheme for Next Generation OFDM Systems

Spectrum sharing and multiple-access techniques are challenging matters for future wireless communication systems. Orthogonal frequency division multiplexing (OFDM) has been considered as the most important physical layer candidate for the next generation wireless systems. Alternatively, multiband OFDM (MB-OFDM) approach has shown some novelty and efficiency for high-rate (HR) WPAN applications and so has been selected for future HR ultrawideband (UWB) systems. Based on an optimization problem formulation, we jointly consider resource allocation and scheduling to define a novel dynamic time-frequency spectrum sharing mechanism based on the MB-OFDM approach. Viewed as a cross-layer solution, the proposed MB-OFDM multiple-access (MB-OFDM-MA) scheme can achieve an efficient multiuser spectrum sharing under QoS constraints. While the optimization formulation results in a high-complexity time-frequency sharing solution, we propose a low-complexity suboptimal solution able to jointly provide fairness provision with the QoS support. Compared with traditional orthogonal frequency division multiple access (OFDMA), the simple time-frequency MB-OFDM-MA approach ensures a high level of fairness among the users while satisfying high-priority users having strict QoS requirements.