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Jung-Shyr WU Jen-Kung CHUNG Yu-Chuan YANG
According to Wu, system performance and capacity degrade due to the co-channel interference between microcells (i. e. hot-spot) and macrocells in a hierarchical structure if the same channel is used. In order to avoid co-channel interference, different channels are assigned for macrocells and microcells. That means multi channels exist in the hierarchical structure. However, hard handoff is necessary for a mobile station (MS) across the boundary of microcell and macrocell because both of them use different channels. Based on a hot-spot overlaying environment, this paper proposes multi-channel access schemes to avoid serious interference between hot-spot and macrocell and thus the capacities are increased. Besides, the same channel can be used in macrocell and hot-spot simultaneously. It makes soft handoff workable and improves the system performance.