Minimizing Power Using Large Bandwidth PPM Transmission and DPCM Source Coding
Minh-Long Pham, Tor Audun Ramstad, Ilangko Balasingham · 2009
To prolong the lifetime of nodes in wireless sensor networks, both transmission cost and processing power should be minimized. For this purpose, we propose a new direct source channel mapping method which utilizes large bandwidth. The system combines a closed-loop Differential Pulse Code Modulation (DPCM) source coder followed by pulse position modulation (PPM) transmission. To accommodate closed-loop prediction over a noisy channel an additional feedback channel is used. Two or more sequential samples are predicted at a time and combined before transmission, thus reducing transmission cost further. Simulations performed on both an auto regressive AR(1) source and a test image over additive white Gaussian noise (AWGN) channel show that our proposed system can achieve significant energy saving for both noiseless and noisy feedback channels without delay.