Channel Segregation Method in a Two-Tier CDMA System

Jung-Shyr WU  Bor-Jiunn HWANG  

IEICE TRANSACTIONS on Communications   Vol.E84-B   No.3   pp.605-613
Publication Date: 2001/03/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Wireless Communication Technology
channel segregation,  CDMA,  

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The CDMA system can provide more capacity than other systems and the hierarchical layer of cells is required for system design to provide a balance between maximizing the number of users perfrequency band and minimizing the network control associated with handoff. However, the co-channel interference from microcell to macrocell and vice versa in such a two-tier structure is different from that in a homogeneous structure. In order to avoid the serious interference, different RF channels should be used in microcell and macrocell in hierarchical structure. The efficient usage of multi-channels for macrocell and microcell is of primary concern herein. In this study, we investigate the channel segregation in a two-tier cellular system. Moreover, we intentionally arrange the procedures for the MS in macrocell and microcell to choose the channel. The macrocell's (resp., microcell's ) channels to be accessed are sorted into three priority groups. In order to justify the merits of the proposed channel segregation method, we define the following three performance measures including capacity gain, response to the variation of traffic loading and system stability. Under the condition of steady-state traffic load, capacity gain is 10% on the average. If the traffic load vary, the system can respond quickly and retrieve the borrowed channels with 2tp time interval as long as appropriate system parameters are chosen.