Iterative decodings used for turbo codes, concatenated codes and LDPC codes have been the main current of Coding Theory. Many researches have been done to improve the structure, algorithms and so on. But, the iterative process itself was not so much improved. On the other hand, in the field of nonlinear analysis, various iterative methods have been studied for nonlinear mappings. We consider the iterative decodings as nonlinear discrete dynamical systems in mathematics and apply iterative processes called Mann type iteration to the iterative decoding process. We will show, by using monotone operator theory, that the proposed method has more extensive stable domain than that of the conventional iterative process. Moreover, we will see the effect of proposed method in computer simulations.

This paper investigates the improvement of the radiation pattern design of transmitting array antenna beamforming and transmission power control (TPC) for forward link of DS-CDMA/FDD system. Optimum transmission beamforming and TPC can be derived from the information of the propagation channel for the forward link, in terms of outage probability minimization. It is assumed that the channel is static and then all mobile stations (MS's) report channel characteristics measured in the forward link to a base station (BS) that can control signal to interference plus noise ratios (SINR's) received by individual MS's using that measured information. Then, for the multi-user environment of a single cell, goal programming (GP) is applied to derive an optimum weight vector of the transmitting array antenna and optimum TPC such that outage probability can be minimized.