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Optimal power distribution over pilot tones for multi-carrier communications over power lines | IEEE Journals & Magazine | IEEE Xplore

Optimal power distribution over pilot tones for multi-carrier communications over power lines


Abstract:

In this paper, we propose a method for finding the optimal distribution of pilot power, which will optimize the performance of multi-carrier transmissions over power line...Show More

Abstract:

In this paper, we propose a method for finding the optimal distribution of pilot power, which will optimize the performance of multi-carrier transmissions over power lines, using comb-type pilots. To find this optimal distribution, we took noise characteristics and channel estimation techniques based on pilot tones associated with interpolation techniques into account. We used two criteria: the classic Mean Square Error of channel estimation and an indicator of performance for multi-tones systems. With these criteria, we used the traditional Lagrange method to obtain different power distributions over pilot tones. In this paper, we show that minimizing the performance indicator is a good criterion, since it evolves as Bit Error Rate. We then present the optimal distribution of pilot power. Our results show that good performances can be achieved with a uniform distribution of pilot power, although the additive noise over pilots is highly colored.
Published in: IEEE Transactions on Consumer Electronics ( Volume: 56, Issue: 3, August 2010)
Page(s): 1794 - 1800
Date of Publication: 28 October 2010

ISSN Information:


I. Introduction

High-speed data transmissions over power lines (PL) constitute a real challenge for engineers and researchers. The low voltage grid has been recently proposed as a potential medium for the “last mile” access network, due to its ability to offer a low-cost existing solution. Various classic modulation schemes, such as multi-carrier modulation, spread spectrum or combinations of these two techniques [1] [2], could be adapted for power line channels. The key benefit of multi-carrier modulation methods (orthogonal frequency division multiplexing (OFDM) or discrete multi-tones (DMT)) is their ability to turn a frequency-selective channel with additive colored noise into a set of independent narrowband subchannels with additive white noise, which greatly simplifies the channel equalization process. In addition, given a stationary channel, it is possible to use a loading algorithm to adapt the sub-carrier modulation parameters to the channel conditions [3] [4], which improves the data rate performance substantially. In both cases, it's clear that final performance is highly dependent on the quality of the channel estimation. In this paper, we focus on most popular channel estimation techniques, which use pilot sub-carriers and piecewise polynomial interpolations.

References

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