Rate-adaptive indoor infrared wireless communication systems using punctured convolutional codes and adaptive PPM

We propose a rate-adaptive indoor infrared wireless communication systems using punctured convolutional codes and adaptive pulse position modulation (PPM) to achieve high bit rate and realize communications even under bad channel conditions with limited transmitter power. The proposed system varies the code rate of the punctured convolutional codes and the modulation order L of L-PPM adaptively according to the channel conditions; when the channel condition is good, low-order PPM and high-rate codes are selected, while high-order PPM and low-rate codes are selected when the channel condition is bad. We analyze the performance of the proposed system on hybrid line-of-sight (LOS) channels. Our results show that the proposed system can achieve high bit rate and realize communications even under bad channel conditions with limited transmitter power by varying the code rate and the modulation order adaptively according to the signal-to-noise ratio (SNR)