| In this thesis, we propose, analyze and assess three novel radio channel access techniques to effectively manage the interference in the reverse links of a cellular CDMA network with the emphasis on the packet data applications. The first scheme is based on the combined use of rate, power and cell control, whereby base station receivers attempt to operate with equal receive power. In the second approach, the temporal variations of the channels are exploited to schedule packet-transmissions in different modes of operations. The third technique uses the overlapping sectors for adaptive sectoring of a cell based on the non-uniform angular traffic around the base stations. All of these approaches are systematically developed based on the fact that both the interference-reduction and the interference-balancing improve the CDMA system performance. The techniques in effect implement interference control at the system level respectively (a) exploiting the source characteristics of the mobiles for network-wide interference-balancing, (b) time separating the signals based on the relative channel conditions and delaying dominant interferers and (c) jointly selecting the best possible set of antenna based on the angular traffic at the antenna and making the user assignment that minimizes the total transmit power. Algorithms for base station selection, transmission rate adjustment and mobile power adaptation for the above schemes are also discussed. Simulation results and numerical examples that compare ours with previously reported techniques demonstrate the effectiveness of the new techniques. |
