The Effect of Soft Handover Threshold on Data Loss and Delay in UMTS Network Using Simulation "OPNET Simulator"

Abstract

UMTS network is one of the most communication network widespread in the world , and there is continuously increasing of number of mobile users , but increasing the number of users causes problems in the network ,and we need ways to solve this problem, one of these ways is decreasing the coverage area of the Node-B’s and increasing its number , this lead to several problems , one of this problems is increase the number of soft handover, and this reason has effect of the QoS parameters . In this project we decided to study the relation between the soft handover threshold and the two main parameters from QoS which are loss and delay using OPNET simulation, to take these results during planning for any network. According to the results that we obtained, we found that increasing soft handover threshold , produce more connection established in the system and more system resources are consumed , this lead to overhead of extra connection caused by soft handover and more loss will be produced. In case of delay, by decreasing the soft handover threshold , the value of the throughput will increase, so that a packet queuing will be produced, and more delay will happen over the network , in the other hand, by decreasing the soft handover threshold the mobile will remain connect with the Node-B for time and distance higher than it at higher threshold before begin executing the handover algorithm , so the higher distance of connection will increase delay between the transmitter and receiver .