Abstract:
To propose an efficient soft handoff procedure for CDMA mobile communication systems using fuzzy inference. In order to control limited trunk-resource efficiency and call quality, the gradient descent method with fuzzy inference system and simple step control are introduced to use. In addition, the other objectives of fuzzy inference system applied to soft handoff are to relieve non-uniform traffic and pilot pollution problems. From the simulations, when compared with IS-95A soft handoff and IS-95B/cdma2000 soft handoff, soft handoff based on fuzzy inference system can give more users, higher trunk-resource efficiency, lower new call blocking probability, lower handoff call blocking probability, and lower system load. However, the quality of communications is acceptable. The fuzzy inference system based soft handoff can better allocate resource in non-uniform traffic area and can solve the pilot pollution problem by giving the performance close to that of normal environment. In addition, the soft handoff using gradient descent with fuzzy inference system and simple step control can control trunk-resource efficiency or call quality according to the requirements. All of the proposed method can be implemented in the real system by changing software and increasing memories to the base station controller