| 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. Furthermore, the technology of wireless spectral resource management includes many sub-areas such as allocation of spectrum, wireless admission control strategy, layer-selection of HCSs, handoff technology, load balancing, power control and capacity analysis and so on. In chapter 2, such three layers as macro-cell layer, micro-cell layer and picro-cell layer construct a cellular model of a multi-code CDMA-based HCS, which synthesizes the two types of HCS structures and 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. An adaptive layer-selection strategy of HCSs will be discussed in chapter 3, in which an adaptive threshold derived from channel utility and two auxiliary thresholds from the micro-cell mobility model based on geometric parameters are introduced. Meanwhile, we estimate the normalized cell dwell time of a mobile unit in the forth-coming cell by means of the correlative between the normalized cell dwell times in this cell and the other past cells. This method developed ways of estimating the cell dwell time of a mobile unit. Chapter 4 describes the handoff technology of HCSs and is divided into three parts. The first part concerns about the handoffs in TDMA/FDMA-basecommunication systems. In this part, we study a bi-directional inter-layer handoff strategy in which wide- and narrow- band services are mapped into different cellular layers. Moreover, a channel allocation algorithm based on cost function and QoS are submitted. The second part presents both a logically layered model based on hierarchical cells and its modified model with "repacking" mechanism permitted. Three logical layers are mapped into two physical layers constructing a HCS. The performance of new calls and handoff calls are analyzed. The QoS degradation of wide-band handoff calls due to inter-layer handoffs between cellular layers and the extra system overloads from the "repacking" mechanism are presented in details respectively. In the third part, we define a new concept of residual capacity-to-loss ratio (RCLR). Based on it, a novel soft handoff criterion (RCLR criterion) of CDMA wireless cellular systems is presented. Compared to minimum path of loss (MPOL) criterion commonly used in systems, RCLR criterion considers not only POL of calls but also load balances in cells. Furthermore, RCLR criterion is applied in a hierarchical cellular structure and performances of the intra-layer soft handoff and inter-layer overflow are studied under both criterions respectively. Finally, a comprehensive conclusion that RCLR criterion reduces both the outage and overflow probability and it shows a better performance compared to MPOL criterion. Obviously, any cellular communication system cannot work without a certain power control procedure. Thus, in chapter 5 we firstly propose the prototype algorithm of an improved distributed power control (IDPC). In this algorithm, the mobile units adjust their transmitter powers according to not only their power levels at last iterative step but also the largest eigenvalue and the second smallest one of the link gain matrix at current time instant. As for this prototype algorithm, link gains for all mobile units must be measured and large burden may be brought in at base stations. Therefore, we developed the prototype algorithm further in a distributed way and lead to the IDPC algorithm. Besides, in IDPC both the...
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