With the convergence of mobile telephony and the Internet, it seems that future telephony data will be transferred on VoIP datagram. Mobility will affect the overall system performance especially for voice communication. Thus, maintaining the quality of voice is necessary. It is important to guarantee that the end-to-end delay must be kept at a certain level. This paper investigates the performance of voice in traffic mix environment. Handover which is based on incoming traffics may cause the system to be unbalanced. A load balancing scheme was deployed to optimise the system capacity and to improve performance. The throughput, end-to-end delay and packet loss are used in measuring the performance. The results show that a better performance can be achieved by deploying this scheme. In addition, the system is able to support more number of connected users.