Performance Analysis and Enhancement of Multiband OFDM for UWB Communications

TL;DR

This paper analyzes the Multiband OFDM system for UWB communications, proposing enhancements with coding and bit-loading, and evaluates their impact on performance and power efficiency.

Contribution

It introduces system performance improvements for Multiband OFDM in UWB by applying Turbo and RA codes and OFDM bit-loading, supported by theoretical and simulation analysis.

Findings

Turbo codes and bit-loading improve power efficiency by over 6 dB.

Multiband OFDM effectively exploits UWB channel frequency selectivity.

System performance approaches the channel cutoff rate.

Abstract

In this paper, we analyze the frequency-hopping orthogonal frequency-division multiplexing (OFDM) system known as Multiband OFDM for high-rate wireless personal area networks (WPANs) based on ultra-wideband (UWB) transmission. Besides considering the standard, we also propose and study system performance enhancements through the application of Turbo and Repeat-Accumulate (RA) codes, as well as OFDM bit-loading. Our methodology consists of (a) a study of the channel model developed under IEEE 802.15 for UWB from a frequency-domain perspective suited for OFDM transmission, (b) development and quantification of appropriate information-theoretic performance measures, (c) comparison of these measures with simulation results for the Multiband OFDM standard proposal as well as our proposed extensions, and (d) the consideration of the influence of practical, imperfect channel estimation on the performance. We find that the current Multiband OFDM standard sufficiently exploits the frequency selectivity of the UWB channel, and that the system performs in the vicinity of the channel cutoff rate. Turbo codes and a reduced-complexity clustered bit-loading algorithm improve the system power efficiency by over 6 dB at a data rate of 480 Mbps.