Interleaved Orthogonal Frequency Division Multiplexing (IOFDM) System

Prasad, VGS and Hari, KVS (2004) Interleaved Orthogonal Frequency Division Multiplexing (IOFDM) System. In: IEEE Transactions on Signal Processing, 52 (6). pp. 1711-1721.

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Abstract

In orthogonal frequency division multiplexing (OFDM) systems, for every block of K data samples, an overhead of L samples of cyclic prefix (CP) or zero padding (ZP) is added to combat frequency selective channels. The code rate, which is defined as the ratio K/(K + L), is a measure of the efficiency of transmitting user information. In this paper, a new system is proposed to increase the code rate without increasing the number of subcarriers and without increasing the bandwidth. The proposed system considers appending the L zeros (ZP) once for every P blocks of data samples, which would increase the code rate to PK/(PK + L). It is assumed that the channel is not varying over the transmission of P consecutive data blocks. In order to recover the P data blocks in a computationally efficient manner, an interleaving scheme is proposed, and the proposed system is called the interleaved OFDM (IOFDM) system. Various issues such as computational complexity, peak-to-average power ratio (PAPR), and the effect of synchronization errors on the performance of the IOFDM system are also presented. Based on a numerical simulation study, the average bit-error-rate (BER) performance of the IOFDM system is shown to be very close to that of the OFDM system for a moderate increase in computational complexity and delay.

Item Type:	Journal Article
Publication:	IEEE Transactions on Signal Processing
Publisher:	IEEE
Additional Information:	Copyright of this article belongs to IEEE. "YEAR IEEE. This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Raman Research Institute's's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to pubs-permissions@ieee.org. By choosing to view this document, you agree to all provisions of the copyright laws protecting it."
Keywords:	Code rate;cyclic prefix;interblock interference;interleaving;OFDM;zero padding.
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	19 Dec 2008 05:21
Last Modified:	19 Sep 2010 04:55
URI:	http://eprints.iisc.ac.in/id/eprint/17100

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