In-Network Multi-Rate Conditional Compression using Multiple Descriptions

Media content distribution constitutes a growing share of the services on the Internet. Two distinct distribution approaches used today are Layered Coding (LC) and Multiple Description Coding (MDC). Current wireless connection technologies, e.g. WiMAX, have properties which make them unsuitable for media distribution using these traditional approaches. In particular, the asymmetric relationship between the uplink and the downlink bandwidth makes the cooperative distribution difficult. A promising concept, termed MDC with Conditional Compression (MDC-CC), has been proposed, which essentially acts as an adaptive hybrid between LC and MDC. In order to facilitate the use of MDC-CC, a new overlay network approach is proposed, using tree of meshes. A control system for managing description distribution and compression in a small mesh is implemented in the discrete event simulator NS-2. The two traditional approaches, MDC and LC, are used as references for the performance evaluation of the proposed scheme. The system is simulated in a heterogeneous network environment, where packet errors are introduced. Moreover, a test is performed at different network loads. Performance gain is shown over both LC and MDC.




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Figure 1. (a) Tree of meshes: Mesh 1 has two child meshes, Mesh 1,1 and Mesh 1,2, where an example of the content distribution flow within a mesh is shown for Mesh 1,1. (b) In-Network conditional compression: Two nodes receive data from a source and exchange a compressed description in order to efficiently improve the delivered media quality.