應用於使用再生能源之無線感測器網路的類比傳輸分散式估計系統

Distributed Estimation with Analog Forwarding Transmissions in Energy-Harvesting Wireless Sensor Networks

鄭元熙(Yuan-Hsi Cheng)

指導教授 ： 洪樂文

國立清華大學/電機資訊學院/通訊工程研究所/碩士(2013年)

摘要

摘要
本論文探討一個再生能源的分散式估計系統。在此系統中，每個感測器量測一個共同的參數，並乘上一放大倍率後，通過正交的通道回傳至匯流中心估測。感測器將會隨機收取附近的再生能源，作為傳輸之用。由於現有電量的不確定性，將影響傳送訊號是否失真，在論文中，我們考慮三種傳送接收的架構。第一種考慮的架構是在避免訊號失真下，在現有電量不夠時，感測器不進行傳輸，匯流中心無法得知傳送資訊，感測器不進行傳輸則匯流中心收到雜訊。第二種狀況下同樣在現有電量不夠時，感測器不進行傳輸，匯流中心擁有傳送資訊，能夠知道哪些感測器未進行傳輸。第三種則在現有電量不夠時，傳送既有的最大電量，匯流中心擁有傳送資訊，能夠知道哪些感測器未進行傳輸。在論文中，我們推導了個架構下最大似然估計器的型式以及相對應的現有電量統計特性。同時，我們嘗試在第二種架構下，找尋一個較佳放大倍率，增進估測的方根差值。最後，我們根據蒙地卡羅模擬分析不同架構的趨勢。

關鍵字

再生能源 ； 分散式估計 ； 無線感測器網路

並列摘要

Distributed estimation in energy-harvesting wireless sensor networks is examined in this
work. Here, each sensor takes a local measurement of the common parameter of interest
and forwards a scaled version of it to the fusion center through orthogonal channels. The
energy available for transmission at each sensor is converted from ambient energy, whose
arrival is random. Two analog forwarding transmission schemes, clipping avoidance and
best effort are proposed. Based on the information of whether the sensors transmit, we
propose three transmission-reception schemes, transmission unaware clipping avoidance
(TUCA), transmission aware clipping avoidance (TACA) and transmission aware best
effort (TABE) schemes. In TUCA and TACA, each sensor transmits only when its required
transmission energy is less than its available battery energy. Besides, in TABE, each sensor
transmits regardless of its available battery energy, in which case, clipping errors may occur.
The information of whether the sensors transmit is known by the fusion center in TACA
and TABE, but not in TUCA. The maximum-likelihood estimator is adopted at the fusion
center and is derived based on the statistics of the energy arrival process. The transmission
policy parameters of TACA are sub-optimized by average of mean square error bound. The
effectiveness of our proposed schemes is demonstrated through Monte Carlo simulations.

並列關鍵字

Energy harvesting ； Distributed estimation ； Wireless sensor networks

參考文獻

IEEE Commun. Mag., vol. 40, no. 8, pp. 102–114, 2002.

[2] J. Yick, B. Mukherjee, and D. Ghosal, “Wireless sensor network survey,” Comput.

energy efficiency in distributed sensing,” IEEE Trans. Signal Process., vol. 55, no. 9,

[4] D. Steingart, “Power sources for wireless sensor networks,” in Energy Harvesting Technologies.

[5] J. A. Paradiso and T. Starner, “Energy scavenging for mobile and wireless electronics,”