1. 後卓越進度報告 蔡育仁老師實驗室 2006/09/04

2. Distribute Source Coding in WSNs Distributed source coding 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. Slepian-Wolf method is a distributed source coding algorithm. … … … : received signal

3. Multiple Access in Distributed Source Coding Systems Distributed source codings which require sequential decoding are sensitive to multiple access techniques in WSNs. For example, to resolve information from the data received by the sink node, Slepian-Wolf method requires data to be received in ordered. Multiple access has to be proper designed in WSNs with distributed source coding to minimize the decoding delay or loss due to sequential decoding.

4. : Sink : Sensor

5. System Considerations We first consider a WSN with slotted ALOHA. There are N nodes in a cluster. Node i transmit a packet in a slot with probability. 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.

6. Goal & Further Work We want to find optimal probability P i based on  Minimize the decoding latency  Minimize the decoding loss rate In future work, we will take packet lengths into consideration to allocate the optimum P i for packets with different lengths.