| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 495275 | Applied Soft Computing | 2015 | 17 Pages |
•Optimal allocation of source and channel coding rates and power levels of nodes.•Minimization of the average and maximum distortion of video received by all nodes.•Mixed integer optimization problems.•Mixed-integer optimization problems arise.•The particle swarm optimization (PSO) algorithm is used.•A hybrid algorithm that combines PSO and active set algorithm is used.
Visual sensor networks (VSNs) consist of spatially distributed video cameras that are capable of compressing and transmitting the video sequences they acquire. We consider a direct-sequence code division multiple access (DS-CDMA) VSN, where each node has its individual requirements in compression bit rate and energy consumption, depending on the corresponding application and the characteristics of the monitored scene. We study two optimization criteria for the optimal allocation of the source and channel coding rates, which assume discrete values, as well as for the power levels of all nodes, which are continuous, under transmission bit rate constraints. The first criterion minimizes the average distortion of the video received by all nodes, while the second one minimizes the maximum video distortion among all nodes. The resulting mixed integer optimization problems are tackled with a modern optimization algorithm, namely particle swarm optimization (PSO), as well as a hybrid scheme that combines PSO with the deterministic Active-Set optimization method. Extensive experimentation on interference-limited as well as noisy environments offers significant intuition regarding the effectiveness of the considered optimization schemes, indicating the impact of the video sequence characteristics on the joint determination of the transmission parameters of the VSN.
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