| As a key technology, the wireless spectral resource management of' hierarchical cellular systems (HCSs) has been a hot spot area and many researches centering on it have been done. Wide service supports and high Quality of Service (QoS) depend on the efficient allocation and utilization of spectrum resource due to limited affordable spectral resources.In chapter 2 and 3, theories this system required are stated, such three layers as macro-cell layer, micro-cell layer and picro-cell layer construct a cellular model. In chapter 4, we present hierarchical cell deployment strategies for designing a high capacity cellular mobile radio system by using tilt antennas. The focuses are on the ratio of required receive power of micro-cell to that of the picro-cell and the tilt angle of the microcell antenna to increase the system capacity. We show the system capacity is dependent on the location of picro-cell and the tilt angle. The optimal tilt angle of picro-cell is obtained by defining the interference trade-off factor that will be used to maximize the capacity. Chapter 6 analyzes the uplink capacity of a cellular CDMA system. Compared to other methods in literatures, the solution of ours to this problem fits real environments better. Such two random processes as shadowing and distance play effects on the propagating of signals. Based on this assumption, the statistics of the outer interference are available.In chapter 5 An layer-selection strategy of HCSs is stated, which is more fit to the real conditions. On this basis, with channel utilities and mobility characteristics considered, a novel multi-services call admission control strategy is submitted. It is validated to be superior to the fixed threshold call admission control strategy commonly used and decreases the signaling loads and the handoff frequency.What we listed in this paper does not necessarily deal with the third or second generation wireless mobile communication systems, more have universal applications leading to future ones. |
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