In this paper, a Hierarchical Cellular System (HCS) supporting two classes of users with high and low velocity is considered. Based on the analytical model of the bidirectional calloverflow scheme, a new dynamic guard channel assignment method is proposed In this method, the number of guard channels in both macrocells and microcells varies in realtime according to the different call traffic load in the HCS, and as a result, the lowest dissatisfaction grade of users is achieved.
Shan Wenhao Fan Pingzhi(institute of Mobile Communications, Southwest Jiaotong University, Chengdu 610031)
A new two level spreading despreading scheme is presented in this paper. By adopting the two level scheme, the Generalized Orthogonal (GO) zone of GO codes can be utilized. In this paper, the forward link of a multi cell CDMA system employing the two level scheme is presented and analyzed. The BER performance obtained by Gaussian Approximation is compared with that of the conventional single level spreading despreading system. The results reveal that the two? level CDMA system introduced in this paper exhibits larger performance gain when time delay can be restricted within a given zone.
HAO Li, FAN Ping zhi (Institute of Mobile Communications, Southwest Jiaotong University, Chengdu, 610031, P.R. China)
