Companding System Based on Time Clustering for Reducing Peak Power of OFDM Symbol in Wireless Communications

Osamu TAKYU; Tomoaki OHTSUKI; Masao NAKAGAWA

doi:10.1093/ietfec/e89-a.7.1884

Companding System Based on Time Clustering for Reducing Peak Power of OFDM Symbol in Wireless Communications

Osamu TAKYU, Tomoaki OHTSUKI, Masao NAKAGAWA

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This paper proposes a novel compressing and expanding (companding) system for OFDM wireless communications that minimizes the compression distortion and so reduces the peak power of OFDM symbols. OFDM systems suffer from large variations in instantaneous peak power. Such transients distort the signals when they are passed through a nonlinear high power amplifier (HPA) prior to transmission. Existing companding systems are far from perfect since the receiver can not accurately estimate the degree of compression applied by the transmitter and thus can not regenerate the original signal by expansion; the key problems are the band pass filter (BPF), HPA, and the noise component enhanced by the channel compensation filter. In the proposed companding system, each symbol is divided into segments, and series of consecutive segments are grouped into clusters. Each cluster is multiplied by a weight equal to the inverse of the largest instantaneous power within the cluster. The receiver estimates the weight used for each time cluster. The weights for all clusters are averaged to mitigate the weight estimation error. As a result, the proposed expander can accurately estimate the weights used and thus well suppress the compression distortion.

Publication: IEICE TRANSACTIONS on Fundamentals Vol.E89-A No.7 pp.1884-1891

Publication Date: 2006/07/01

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Online ISSN: 1745-1337

DOI: 10.1093/ietfec/e89-a.7.1884

Type of Manuscript: Special Section PAPER (Special Section on Multi-dimensional Mobile Information Networks)

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Osamu TAKYU, Tomoaki OHTSUKI, Masao NAKAGAWA, "Companding System Based on Time Clustering for Reducing Peak Power of OFDM Symbol in Wireless Communications" in IEICE TRANSACTIONS on Fundamentals, vol. E89-A, no. 7, pp. 1884-1891, July 2006, doi: 10.1093/ietfec/e89-a.7.1884.
Abstract: This paper proposes a novel compressing and expanding (companding) system for OFDM wireless communications that minimizes the compression distortion and so reduces the peak power of OFDM symbols. OFDM systems suffer from large variations in instantaneous peak power. Such transients distort the signals when they are passed through a nonlinear high power amplifier (HPA) prior to transmission. Existing companding systems are far from perfect since the receiver can not accurately estimate the degree of compression applied by the transmitter and thus can not regenerate the original signal by expansion; the key problems are the band pass filter (BPF), HPA, and the noise component enhanced by the channel compensation filter. In the proposed companding system, each symbol is divided into segments, and series of consecutive segments are grouped into clusters. Each cluster is multiplied by a weight equal to the inverse of the largest instantaneous power within the cluster. The receiver estimates the weight used for each time cluster. The weights for all clusters are averaged to mitigate the weight estimation error. As a result, the proposed expander can accurately estimate the weights used and thus well suppress the compression distortion.
URL: https://global.ieice.org/en_transactions/fundamentals/10.1093/ietfec/e89-a.7.1884/_p

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@ARTICLE{e89-a_7_1884,
author={Osamu TAKYU, Tomoaki OHTSUKI, Masao NAKAGAWA, },
journal={IEICE TRANSACTIONS on Fundamentals},
title={Companding System Based on Time Clustering for Reducing Peak Power of OFDM Symbol in Wireless Communications},
year={2006},
volume={E89-A},
number={7},
pages={1884-1891},
abstract={This paper proposes a novel compressing and expanding (companding) system for OFDM wireless communications that minimizes the compression distortion and so reduces the peak power of OFDM symbols. OFDM systems suffer from large variations in instantaneous peak power. Such transients distort the signals when they are passed through a nonlinear high power amplifier (HPA) prior to transmission. Existing companding systems are far from perfect since the receiver can not accurately estimate the degree of compression applied by the transmitter and thus can not regenerate the original signal by expansion; the key problems are the band pass filter (BPF), HPA, and the noise component enhanced by the channel compensation filter. In the proposed companding system, each symbol is divided into segments, and series of consecutive segments are grouped into clusters. Each cluster is multiplied by a weight equal to the inverse of the largest instantaneous power within the cluster. The receiver estimates the weight used for each time cluster. The weights for all clusters are averaged to mitigate the weight estimation error. As a result, the proposed expander can accurately estimate the weights used and thus well suppress the compression distortion.},
keywords={},
doi={10.1093/ietfec/e89-a.7.1884},
ISSN={1745-1337},
month={July},}

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TY - JOUR
TI - Companding System Based on Time Clustering for Reducing Peak Power of OFDM Symbol in Wireless Communications
T2 - IEICE TRANSACTIONS on Fundamentals
SP - 1884
EP - 1891
AU - Osamu TAKYU
AU - Tomoaki OHTSUKI
AU - Masao NAKAGAWA
PY - 2006
DO - 10.1093/ietfec/e89-a.7.1884
JO - IEICE TRANSACTIONS on Fundamentals
SN - 1745-1337
VL - E89-A
IS - 7
JA - IEICE TRANSACTIONS on Fundamentals
Y1 - July 2006
AB - This paper proposes a novel compressing and expanding (companding) system for OFDM wireless communications that minimizes the compression distortion and so reduces the peak power of OFDM symbols. OFDM systems suffer from large variations in instantaneous peak power. Such transients distort the signals when they are passed through a nonlinear high power amplifier (HPA) prior to transmission. Existing companding systems are far from perfect since the receiver can not accurately estimate the degree of compression applied by the transmitter and thus can not regenerate the original signal by expansion; the key problems are the band pass filter (BPF), HPA, and the noise component enhanced by the channel compensation filter. In the proposed companding system, each symbol is divided into segments, and series of consecutive segments are grouped into clusters. Each cluster is multiplied by a weight equal to the inverse of the largest instantaneous power within the cluster. The receiver estimates the weight used for each time cluster. The weights for all clusters are averaged to mitigate the weight estimation error. As a result, the proposed expander can accurately estimate the weights used and thus well suppress the compression distortion.
ER -