Low complexity zero-padding zero-jamming DMT systems

Discrete multitone (DMT) systems have been widely adopted in broadband communications. When the transmission channel is frequency selective, there will be interblock interference (IBI). IBI can be avoided by zero-padding (ZP) [1]. Another solution is to allow IBI during transmission, and at the receiver the samples that contain IBI are removed by zero-jamming (ZJ) [2]. The ZP DMT system employs the ZP technique whereas the CP DMT system where a cyclic prefix is added at the transmitter uses the ZJ technique. In both the ZP DMT and CP DMT systems, the number of redundant samples are larger than or equal to the channel order. In this paper, we propose a ZP-ZJ DMT system. By combining ZP and ZJ techniques, we are able to reduce the number of redundant samples needed for IBI elimination by as much as one half. The transmitter of the ZP-ZJ DMT system involves only one IFFT operation and its receiver can be implemented efficiently using a small number of FFT/IFFT operations. Simulation shows that the bandwidth efficient ZP-ZJ DMT system can sometimes outperform the CP DMT system.