PROPOSED MULTICHANNEL ACCESS SCHEMES FOR HOT-SPOT UNDERRELAYING CDMA CELLULAR-SYSTEMS

According to Wu[1], system performance and capacity degrade due to the co-channel interference between microcells (i.e. hot-spot) and macroc ells in a hierarchical structure if the same channel is used. in order to avc,id co-channel interference, different channels are assigned fo r macrocells and microcells. That means multi channels exist in the hi erarchical structure. However, hard handoff is necessary for a mobile station (MS) across the boundary of microcell and macrocell because bo th of them use different channels. Based on a hot-spot overlaying envi ronment, this paper proposes multi-channel access schemes to avoid ser ious interference between hot-spot and macrocell and thus the capaciti es are increased. Besides, the same channel can be used in macrocell a nd hot-spot simultaneously. It makes soft handoff workable and improve s the system performance.