A practical system for improved efficiency in frequency division multiplexed wireless networks

Submitted by richard on Thu, 10/17/2013 - 18:40
Richard G. Clegg, Safa Isam, Ioannis Kanaris and Izzat Darwazeh
IET Communications, Volume 6, issue 4, p. 449-457
Spectral efficiency is a key design issue for all wireless communication systems. Orthogonal frequency
division multiplexing (OFDM) is a very well-known technique for efficient data transmission over many
carriers overlapped in frequency. Recently, several papers have appeared which describe spectrally ef-
ficient variations of multi-carrier systems where the condition of orthogonality is dropped. Proposed
techniques suffer from two weaknesses: Firstly, the complexity of generating the signal is increased.
Secondly, the signal detection is computationally demanding. Known methods suffer either unusably
high complexity or high error rates because of the inter-carrier interference. This work addresses both
problems by proposing new transmitter and receiver architectures whose design is based on using the
simplification that a rational Spectrally Efficient Frequency Division Multiplexing (SEFDM) system can
be treated as a set of overlapped and interleaving OFDM systems.
The efficacy of the proposed designs is shown through detailed simulation of systems with different
signal types and carrier dimensions. The decoder is heuristic but in practice produces very good results
which are close to the theoretical best performance in a variety of settings. The system is able to produce
efficiency gains of up to 20% with negligible impact on the required signal to noise ratio.

This paper looks at the problem of sending data using a variation on Orthogonal Frequency Division Multiplexing. In this variant frequencies are packed slightly closer. This means the frequencies are no longer orthogonal but more may be packed into a given amount of spectrum.

author={Clegg, R.G. and Isam, S. and Kanaras, I. and Darwazeh, I.},
journal={Communications, IET},
title={A practical system for improved efficiency in frequency division multiplexed wireless networks},
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