無線感知網路之壓縮率控制

Compression Rate Control in Wireless Sensor Networks

林俊隆(Chun-Lung Lin)

《電腦與通訊》 143期 (2012/02) Pp. 110-117

https://doi.org/10.29917/CCLTJ.201202.0016

摘要

近年來，感知器網路常採用失真壓縮技術收集長期的資料並分析資料趨勢及感興趣的特定資料樣板，在這些應用中，感知器被佈建來收集大量連續資料，通常允許失真及非及時的資料，且相鄰感知器資料常有時間和空間的關聯性，因此中間節點的感知器將自己所感知的資料及從鄰近感知器所傳輸過來資料進行失真壓縮以延長系統運作生命期。這篇論文探討位元率與失真度最佳化分配問題，在滿足可接受的資料失真條件下，最佳的決定如何分配各個感知器的壓縮位元率，目的是使用最少傳輸位元，蒐集到品質最好的資料。本篇論文為分配問題提出一個最佳解，也根據最佳解提出一個分散式分配的策略。所提的方法使用實際資料模擬，結果顯示最佳化分配與分散式分配策略相較於平均分配策略的確能大量的減少網路傳輸資料量。

關鍵字

無線感知器網路 ； 最佳化壓縮率配置 ； 分散式壓縮率配置

並列摘要

Lossy compression techniques are commonly used in wireless sensor networks for long-term data-gathering applications that attempt to identify trends or other interesting patterns in an entire system, since a data packet need not always be completely and immediately transmitted to the sink. In the applications, sensors are instructed to periodically sense massive data, and the data collected by nearby sensor nodes is also highly correlated both in time and in space. To exploit the data correlation, a non-terminal sensor node jointly encodes its own sensed data and the data received from its nearby nodes. The tendency for these nodes to have a high spatial correlation means that these data packets can be efficiently compressed together using a rate-distortion strategy. This article addresses the optimal rate allocation problem, which determines an optimal bit rate of each sensor based on the target overall distortion to minimize the network transmission cost. A centralized optimal allocation scheme and its distributed version are proposed. The proposed methods are evaluated via simulations using real-world data datasets. The simulation results show that the proposed methods can greatly reduce the transmission cost as compared to the uniform allocation scheme.

並列關鍵字

Wireless Sensor Networks ； WSNs ； Optimal Rate Allocation ； ORA ； Distributed Rate Allocation ； DRA