1. 後卓越進度報告 蔡育仁老師實驗室 2006/11/13

2. Distribute Source Coding (DSC) in WSNs 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

3. : Sensor : Sink Slepian-Wolf Distributed Source Coding Decoding Order

4. DSC with Random Access — Assumptions & Goals Performance of a DSC scheme in a slotted ALOHA WSN has been investigated.  Consider a cluster with N sensors and a sink. Node i transmit a packet in a slot with probability P i.  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 P i based on  Minimize the decoding latency  Minimize the decoding loss rate

5. 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

6. Simulation Results Numerical Results G = 0.5 G = 1 G = 1.5 G = 2 Average Traffic Load Time Slots M Traffic Load Analysis

7. 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 P i for packets with different lengths.