Research And Realization On Soft Handoff Arithmetic In Cdma System

Soft handoff is one of the key technologies in the CDMA system, It plays an important role in controlling and optimizing radio resources of the system.This paper introduces some typical former soft handoff arithmetic in detail and proposes three improved soft handoff algorithms. Then put one of them into practice according to the need of CMT communicational system. The main contribution of this paper is as follows:Firstly, the balance of cell traffic load is not taken into account as one criteria of making soft handoff decisions in the traditional soft handoff algorithms.In this paper,we get a new arithmetic by introducing a fuzzy adaptive parameter T based on soft handoff arithmetic of cdma2000.It has been observed,from simulation that this new arithmetic can balance the traffic to some extent,and gain a higher efficiency.Secondly,we propose an improved handoff strategy with combination of channel reservation,preemptive priority and queuing for integrated real-time and non real-time service cellular mobile systems. Simulation results show that blocking probability of real-time service and forced termination probability of real-time service performances are significantly reduced with our strategy without sacrificing none ral-time service QoS much. Our strategy improves the channel utilization and provides better QoS for mobile users.Thirdly,a Multi-class Services fuzzy-based adaptive channel reservation scheme for handoff is proposed for keeping the QoS of high priority handoff traffic. Analysis shows that good QoS can be obtained using the channel allocation and handoff strategy proposed.Finally,a soft handoff module of CMT mobile communication system is designed and realized.And this paper employs a fzzy adaptive parameter soft handoff arithmetic.Tests can prove this module can meet the demand of CMT mobile communication system's performance,also enhanced efficiency.