Advanced resource utilization in wireless networks

Efficient resource utilization techniques are very important to wireless communication systems due to the limited spectrum resource. In this dissertation, we propose advanced resource utilization techniques for multiuser and multiple-input-multiple-output (MIMO) systems. Multiuser systems can provide multiuser diversity gains by assigning channels to users with higher channel gains. To avoid the extensive information exchange with the access point for the uplink access, we propose a distributed opportunistic access scheme. Through a judicious design of a novel backoff mechanism to utilize the channel information and reduce collisions, significant multiuser diversity gains are achieved. We further extend our proposed scheme to heterogenous and orthogonal frequency division multiple access (OFDMA) systems. Compared with centralized and distributed access schemes in the literature, our proposed schemes reduce overhead and achieve a higher throughput. In this dissertation, we also adopt game theory to design multiple access control (MAC) schemes in slotted Aloha systems. A distributed fair pricing strategy is proposed for slotted Aloha systems in which users act selfishly to improve their own utilities for both the collision model and the multipacket reception (MPR) model by appropriately designing the Nash equilibrium thresholds. Our simulation results show that significant multiuser diversity gains are achieved in terms of energy consumption and/or spectral efficiency. In addition, we present a novel scheme for integrating opportunistic space-time block codes (STBC) with orthogonal frequency division multiplexing (OFDM) for frequencyselective channels with an unequal error protection capability. Our proposed new scheme optimizes the tradeoff between coding gain and peak-to-average ratio (PAR) while minimizing inter-carrier interference in the presence of carrier frequency offset. A robust STBC transmission scheme is also proposed in this dissertation to combat timing synchronization errors over frequency-selective spatial-division-multiple-access channels. Based on our derived equivalent channel model and statistical channel power gain profiles, a robust statistical bit loading algorithm is proposed to optimize the BER performance in scenarios where link adaptation based on instantaneous channel information is infeasible or undesirable. Simulation results show that our proposed scheme is robust to timing synchronization errors and provides appreciable performance gains.