Iterative Compressive Sensing for the Cancellation of Clipping Noise in Underwater Acoustic OFDM System

摘要

Due to the characteristics of the underwater acoustic channel especially the limited bandwidth, orthogonal frequency division multiplexing (OFDM) is widely used because of its high spectrum efficiency and ability in anti-multipath fading. However OFDM also has its drawbacks, one of which is the relatively high peak-to-average ratio (PAPR). The problem leads to saturation in the power amplifier and consequently distorts the signal which is not allowed in the underwater acoustic communication. Clipping as the most classic and convenience way is widely applied to address the high PAPR. However, it introduces additional noise that degrades the system performance. In this paper compressed sensing (CS) technique is proposed to mitigate the clipping noise. The scheme exploited pilot tones and data tones instead of reserved tones, which is different from the previous works and causes less loss of data rate. Also, in contrast with previous works, to minimizing the influence of underwater acoustic channel, compressed sensing in channel estimating is also adopted during mitigating the clipping noise, which can provide more accurate channel characteristics for estimating the clipping noise than traditional method such as LS or MMSE. The iterative CS technology proposed in this article can significantly improve the communication quality even in low SNR.