We describe a new characteristic of soft handoff, call failure when a mobile moves from the handoff region to the normal region, and introduce the metric of region-transition failure probability to more accurately assess the performance of CDMA systems that support real-time video streaming services. This characteristic has not been considered in previous research. Simulations show that this failure must be considered since it significantly degrades system performance.

In this letter, we propose an efficient channel allocation scheme to provide multicast traffic in multitier cellular systems. Our proposed scheme allocates microcell/macrocell channels based on the 'microcell-group size' and probability. Also, we analyze the performance of the scheme in view of the call blocking probability in case of considering overflow traffic or not. Numerical results show that our proposed scheme exhibits a better performance than conventional schemes.

While spatial reuse in a high-speed ring increases the throughput performance, it leads to a fairness problem in distributing the network bandwidth among distinct nodes. To alleviate this problem, fairness control algorithms based on a packet window have been developed. Under these algorithms, satisfied nodes are forced to pass empty slots to starved downstream nodes until their windows are refilled by a reset signal. This regulation incurs a bandwidth waste corresponding to the travel distance of those empty slots. In this paper, a waste-free fairness control method based on a two-layer window composed of the cycle and packet windows is developed. Using the proposed method, packets allocated to multiple fairness cycles are simultaneously transferred and, in consequence, the otherwise wasted bandwidth can be reused to carry, in advance, packets allocated to future fairness cycles. This method is applied to two typical ring protocols with only the packet window, ATMR and MetaRing, and their performances are investigated. The simulation results show that the cycle window is very effective to improve the performance of the ATMR and MetaRing protocols.

In the future PCS (personal communication system), it is needed to use wireless and wired resources most efficiently, because of the increase of users and various multimedia traffics. Therefore, there have been much researches on CDMA (code division multiple access) whose frequency reuse is most efficient. Here, if one of PCS subsystems is broken down because of system, power, or network failure, it is impossible to serve PCS user terminals anymore. To solve this problem, the integrated network management function is required to examine each subsystem periodically or non-periodically, and handle each error properly, and inform network manager or PCS service management center of error occurrence. In this paper, we consider standard SNMP (simple network management protocol) and CMIP (common management information protocol) as the management protocol of PCS land mobile network. Also, we present the overall structure of management information taking CDMA PCS characteristics into consideration. Since there were little considerations for characteristics specific to cellular environment in the conventional network management systems, we add the CDMA PCS-specific management informations to each agent systems. Thereafter, we present the optimum network management protocol stack for PCS environment which provides TMN (telecommunications management network) interfaces among each subsystems as well as including wired networks.