Study of Per Tone Equalization Technique and its implementation for xDSL system
Date Issued
2004-05-31
Date
2004-05-31
Author(s)
DOI
922622E002012CC3
Abstract
Orthogonal Frequency Division
Multiplexer (OFDM) and Discrete
Multi-Tone (DMT) are these of the
multi-carrier modulation techniques,
which have been extensively adopted
both in wire and wireless
communication, such as 802.11a
standard, and xDSL systems. In
OFDM/DMT modulation scheme, the
communication channel is divided into a
bank of orthogonal sub-channels in the
frequency domain. The primary
advantage of the multi-carrier
modulation is that the bits allocation for
each sub-channels can be dynamic based
on the quality of each channel. In high
SNR sub-channels, we can allocate more
bits to transfer. On the contrast, fewer
bits are allocated in these channels with
low SNR. As the result, we can make
full use of the bandwidth with a
sophisticated adaptive-bits-allocation
approach.
One major disadvantage of the
OFDM/DMT scheme is that it is very
sensitive to Inter Symbol Interference
(ISI). In the xDSL systems, time domain
equalization (TEQ) is often
implemented to eliminate the
impairment of ISI. The hardware cost of
TEQ, however, is very high; especially,
when the channel impulse response is
very longer. On the other hand, to
operate in different systems with one
hardware-module, such as in xDSL
systems, we must implement TEQ in the
worst case. This is not desired when the
tap-delay line of TEQ is very different
among the xDSL systems. In the
updated research [1], the equalization is
performed for each sub-carrier. This will
improve the overall performance. In the
project, based on [1], we will focus on
the study and implementation of xDSL
equalizer in frequency domain to
achieve low cost, low power, and high
performance (high SINR).
Subjects
OFDM/DMT
TEQ
Per Tone FEQ
XDSL
Publisher
臺北市：國立臺灣大學電子工程學研究所
Type
report
File(s)![Thumbnail Image]()
Loading...
Name
922622E002012CC3.pdf
Size
75.8 KB
Format
Adobe PDF
Checksum
(MD5):84b5f338b78a8db8c0dc0e0aa074fb61