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Physical Layer Data Fusion Via Distributed Co-Phasing With General Signal Constellations

Manesh, A and Murthy, Chandra R and Annavajjala, Ramesh (2015) Physical Layer Data Fusion Via Distributed Co-Phasing With General Signal Constellations. In: IEEE TRANSACTIONS ON SIGNAL PROCESSING, 63 (17). pp. 4660-4672.

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Official URL: http://dx.doi.org/10.1109/TSP.2015.2442954


This paper studies a pilot-assisted physical layer data fusion technique known as Distributed Co-Phasing (DCP). In this two-phase scheme, the sensors first estimate the channel to the fusion center (FC) using pilots sent by the latter; and then they simultaneously transmit their common data by pre-rotating them by the estimated channel phase, thereby achieving physical layer data fusion. First, by analyzing the symmetric mutual information of the system, it is shown that the use of higher order constellations (HOC) can improve the throughput of DCP compared to the binary signaling considered heretofore. Using an HOC in the DCP setting requires the estimation of the composite DCP channel at the FC for data decoding. To this end, two blind algorithms are proposed: 1) power method, and 2) modified K-means algorithm. The latter algorithm is shown to be computationally efficient and converges significantly faster than the conventional K-means algorithm. Analytical expressions for the probability of error are derived, and it is found that even at moderate to low SNRs, the modified K-means algorithm achieves a probability of error comparable to that achievable with a perfect channel estimate at the FC, while requiring no pilot symbols to be transmitted from the sensor nodes. Also, the problem of signal corruption due to imperfect DCP is investigated, and constellation shaping to minimize the probability of signal corruption is proposed and analyzed. The analysis is validated, and the promising performance of DCP for energy-efficient physical layer data fusion is illustrated, using Monte Carlo simulations.

Item Type: Journal Article
Additional Information: Copy right for this article belongs to the IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA
Keywords: Distributed co-phasing; K-means algorithm; sensor networks; data fusion; mutual information; Nakagami-m fading
Department/Centre: Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited: 24 Sep 2015 04:52
Last Modified: 24 Sep 2015 04:52
URI: http://eprints.iisc.ac.in/id/eprint/52391

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