Abstract
Time-domain equalization is crucial in reducing channel dispersion and canceling interference in multicarrier systems. The equalizer is a finite impulse response (FIR) filter with the purpose that the delay spread of the combined channel-plus-equalizer IR is not longer than the cyclic prefix length. In this paper, a specific framework of long FIR channel-shortening problem is studied. In fact, approximated by a stable pole-zero model, we show that the channel transfer function poles introduce interference. Hence, to cancel bad poles, we propose the use of lattice structure to implement the channel shortener which places their zeros very close to critical channel poles and cancels them out. For low complexity implementation, we adopt adaptive algorithms to design the lattice channel shorteners. This paper analyzes the lattice structure performances of two blind adaptive channel shorteners: sum-squared autocorrelation minimization and multicarrier equalization by restoration of redundancy algorithms. The proposed implementation performances are given in terms of bit rate, and the simulation results are studied in the context of asymmetric digital subscriber line system.
Highlights
Multicarrier (MC) modulation has various advantages that make it useful for a wide variety of digital communication systems [1]
In order to shorten the recursive channel, an effective time-domain equalizer (TEQ) will place their zeros on the critical poles to cancel them out
Inspired by the behavior of the lattice implementation of the squared autocorrelation minimization (SAM) cost function, we examine throughout this section the benefit that can be accomplished by implementing multicarrier equalization by restoration of redundancy (MERRY) with the same structure
Summary
Multicarrier (MC) modulation has various advantages that make it useful for a wide variety of digital communication systems [1]. A highly time-dispersive channel leads to a significant reduction of the transmission data rate since the received signal is corrupted by both inter-carrier and inter-symbol interferences. To avoid such a performance degradation, a channel-shortening technique, commonly referred to as time-domain equalizer (TEQ), is introduced at the. It is proven that in twisted pair lines, the channel is well modeled by a recursive filter with a slowly decaying IR [8,9] This means that the channel transfer function presents poles close to the unit circle (UC). It is worth noting that inaccurate zeros position results in a limited channel-shortening performance, which motivates the use of lattice structure to cancel channel poles. The notation sk,n is used to present the nth MC sample transmitted or received at kth MC symbol period
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
