Optimization of UTRA SHO Algorithm

Since the emergence of W-CDMA technology as an air interface of 3G mobile communication systems, extensive researches have been carried out to improve the performance of these systems. Most of these works show that the soft handover technique plays an important role in improving W-CDMA system performance. Several algorithms were developed to meet certain requirements of system such as capacity improvement, interference reduction and traffic balancing (Won-Ik Kim et al., 2002; Viterbi et al., 1994). Because of this the necessity to optimize these algorithms further increased. In this paper we present a dynamic simulator using MATLAB software to optimize the soft handover (SHO) parameters of UTRA networks by taking the number of SHOs as an optimization criterion. The simulations show that the minimum number of SHOs can be obtained when the active set (AS) size, Add thereshold (Add_th) and Drop threshold (Drop_th) were kept to 2, 2.5 and 3, respectively.