Low power design for wireless communication system

Power consumption has become the most important criteria in the design of wireless portable devices. In this work, we investigate the interaction between the wireless application domain knowledge and the general low power design technique for the optimal low power system design. In particular we look at the following areas: Low power turbo-code codec design, Low power OFDM receiver design and a battery-life-driven power control method for low power wireless system design.; For Turbo-code, we propose a low power VLSI architecture of SOVA based Turbo-code decoder using scarce state transition scheme (SST).; We also propose an adaptive reduced complexity Log-map algorithm (ARLog-map). A test chip based on this architecture for K = 3, turbo-code decoding has been designed and fabricated using TSMC 0.35um process.; Another area that we work on for low power design is the data representation area. We investigate at the feasibility of using log number system (LNS) instead of linear binary number system to reduce the complexity of operation. We propose a low complexity orthogonal frequency-division multiplexing (OFDM) receiver using Log-FFT for coded OFDM system.; Channel estimation is of crucial importance for the coherent detection of OFDM system. By exploiting the time correlation character of channel impulse response, we suggest a low power design method for channel estimation using differential and threshold schemes.; We study the power control methods for different optimization objectives given the knowledge of battery power capacity. We target for single cell multi-rate code division multiple access (CDMA) system with perfect successive interference cancellation (SIC) as our specific system. Different ordering for the SIC will lead to different power control mechanism. In particular we propose some simple ordering schemes for SIC so that we can maximize the minimum transmission/connection time for a group of users within the same cell. We also propose schemes which can increase the total amount of data that a group of users can transmit within the same cell before all of them run out of battery.