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後卓越進度報告. 蔡育仁老師實驗室 2006/11/13. Distributed source coding (DSC) is a data compression technique to reduce the redundancy without direct communication among sensor nodes. Sensors are encoders to individually encode their received information related to a single event.
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後卓越進度報告 蔡育仁老師實驗室 2006/11/13
Distributed source coding (DSC) is a data compression technique to reduce the redundancy without direct communication among sensor nodes. Sensors are encoders to individually encode their received information related to a single event. E.g., Slepian-Wolf method is a widely used distributed source coding algorithm. : received signal … … … Distribute Source Coding (DSC) in WSNs
Slepian-Wolf Distributed Source Coding : Sensor Decoding Order : Sink
DSC with Random Access — Assumptions & Goals • Performance of a DSC scheme in a slotted ALOHA WSN has been investigated. • Consider a cluster with Nsensors and a sink. Node itransmit a packet in a slot with probability Pi. • If the packet of node i corresponding to an event is received successfully, this node will not transmit other packets for this event again. • The packet of node i can be reconstructed if the packet of node 1 to node i–1 was received successfully. • Goal — Find optimal probability Pibased on • Minimize the decoding latency • Minimize the decoding loss rate
DSC with Random Access —Analysis • Traffic load analysis • Initial total traffic load • The average remainder traffic at the k-th slot can be calculated iteratively and approximately • Average number of successfully reconstructed packets at the K-th slot
2 G = 0.5 G = 1 G = 1.5 G = 2 1.8 1.6 1.4 1.2 Simulation Results Numerical Results 1 0.8 0.6 0.4 0.2 0 100 0 10 20 30 40 50 60 70 80 90 Traffic Load Analysis Average Traffic Load Time Slots M
DSC with Random Access — Future Work • Find the exact analytical form and the statistics of the decoding delay and decoding loss. • Take packet lengths into consideration to allocate the optimum Pi for packets with different lengths.