Code division multiple access (CDMA) is the most promising access scheme for the 3rd generation mobile communications system. Because it is indispensable in coping with multimedia communications in the 3rd generation system, CDMA packet transmission with high transmission efficiency over a wide variety of traffic characteristics is also necessary for the system. There are two kinds of packet transmission, the reservation method (RM) and the contention method (CM), used as media access control (MAC) methods in radio packet transmission. The two MAC methods are evaluated and compared based on capacity. As a result, it is shown that it is necessary to switch MAC methods depending on the traffic characteristics. Moreover, this paper denotes a switching method between physical channels and a handover procedure, and quantitatively evaluates the switching frequency between physical channels and the hard handover (HHO) frequency.

Since code-division multiple-access (CDMA) capacity is interference limited, call admission control (CAC) must guarantee both a grade of service (GoS), i.e., the blocking rate, and a quality of service (QoS), i.e., the loss probability of communication quality. This paper describes the development of a new capacity design method based on these two concepts. Theoretical expressions for GoS and QoS as functions of traffic intensity and CAC thresholds are first derived from the traffic theory viewpoint, and then a design method using these expressions is presented. At that time, two strategies for CAC are assumed. One is based on the number of users, and the other is based on the interference level. Computer simulation results are presented that strongly support the proposed design method. Furthermore, numerical examples and a performance comparison of the two strategies considering various propagation parameters, nonuniform traffic distributions, and various transmission rates are shown.