Infrared wireless systems with multiple subcarrier modulation to reduce average optical power by allocating appropriate amplitude for corresponding subcarrier to the punctured patterns

摘要

We propose infrared wireless systems with multiple subcarrier modulation to reduce average optical power by allocating appropriate amplitude for corresponding subcarrier to the punctured patterns. Although the punctured bits are not allocated to the subcarrier amplitude in the systems with rate-conpatible punctured convolutional codes, in the proposed systems, they are replaced by the dummy information, and the appropriate amplitudes are allocated to reduce the average optical power. In this paper, we propose two schemes to select the amplitude values of subcarriers for the bit positions corresponding to '0' in the punctured patterns: one scheme uses only the zero amplitude value (proposed 1), and the other scheme selects the appropriate amplitude value among 0, and ±1 in order to minimize average optical power (proposed 2). We show that the proposed 2 can achieve the best BER performance at the same average optical power. We also show that the proposed 2 can achieve the best SNR performance at the same number of subcarriers.