With the increasing adoption of wireless technology, it is reasonable to expect an increase in the demand for supporting both real-time multimedia and high rate reliable data services. Next generation wireless systems employ Orthogonal Frequency Division Multiplexing (OFDM) physical layer owing to the high data rate transmissions that are possible without increase in bandwidth. Towards improving the performance of these systems, we look at the design of resource allocation algorithms at medium-access iayer, and their impact on higher layers. While TCP-based elastic traffic needs reliable transport, UDP-based real-time applications have stringent delay and rate requirements. The MAC algorithms while catering to the heterogeneous service needs of these higher layers, tradeoff between maximizing the system capacity and providing fairness among users. The novelty of this work is the proposal of various channel-aware resource allocation algorithms at the MAC layer, which can result in significant performance gains in an OFDM based wireless system.