Maintaining handoff QoS in TD-CDMA networks

Quality of service (QoS) at the call or flow level in time division code division multiple access (TD-CDMA) networks is an important topic that has not yet received much attention. We propose a two tier admission and scheduling policy that keeps the probability of violating the bit error rate (BER) limits for new call arrivals below a specified threshold. The proposed policy allocates bandwidth for newly arrived calls on the basis of the outage probability threshold. It also reserves bandwidth in all surrounding sectors for future handoff events, which minimizes the probability that the handoff call from one sector will cause an outage condition in the target sector. The performance of the proposed policy is evaluated through simulations in the presence of voice and data traffic types. We show that the proposed scheme can provide satisfactory quality for a call or data flow during its lifetime.