 
Summary: An Optimized CostEffective Multicarrier Transceiver for TwoRay Channels
Naofal AlDhahir \Lambda , Member IEEE
Information Systems Laboratory
Stanford University, Stanford CA 94305
EDICS Category 2:8 (DSP Applications)
Abstract
The optimum set of modulation filters for multicarrier modulation on tworay channels is derived in
closedform. These filters are shown to be sinusoidal even for a finite number of carriers.
The proposed modulation scheme optimizes the performance of tworay channels corrupted by addi
tive white Gaussian noise without incurring the data rate loss associated with FFTbased multicarrier
transceivers. The case of multipleray channels is also considered.
I. Introduction
Multicarrier modulation (MCM) has attracted considerable attention recently as a viable transmission tech
nology on spectrallyshaped channels [7, 3]. It involves the use of an orthogonal set of modulation basis
vectors at the transmitter to partition the channel response into a large number of parallel, independent, and
memoryless subchannels that can be individually decoded.
The optimum modulation basis vectors require the computation of the complete eigendecomposition of
a channeldependent matrix, which becomes a formidable task even for a moderate number of subchannels
[7]. In a suboptimum but computationallyefficient implementation of MCM known as the discrete multitone
transceiver (DMT), a cyclic prefix is added to each input block to make the the channel matrix circulant, and
