Adaptive Multimedia Flow Splitting over WiMAX and WiFi Links

Jong-Ok KIM  Toshiaki YAMAMOTO  Akira YAMAGUCHI  Sadao OBANA  

IEICE TRANSACTIONS on Communications   Vol.E91-B   No.10   pp.3085-3094
Publication Date: 2008/10/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e91-b.10.3085
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Next-Generation Mobile Multimedia Communications)
cognitive access network,  airtime cost,  multimedia transmission,  WiMAX,  WiFi,  

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To meet the bandwidth requirements of multimedia services, multipath transmission is a promising solution. In this paper, we consider multi-access networks, where WiMAX and WiFi links are set up at the same time. Multipath transmission suffers from the intrinsic problem of out-of-order packet delivery. This has an adverse impact on TCP and even UDP-based delay sensitive applications. However, multimedia streaming services allow some tolerance to transmission delay. Motivated by this observation, we investigate how to split multimedia flows over heterogeneous links. Wireless link capacity varies widely over time due to dynamic radio conditions. The capacity variations should be promptly reflected in traffic splitting in order to accomplish an equal load-balance. A practical prototype system has been implemented. We have performed extensive measurements from a prototype system. Through practical experimental results, we could verify two major research goals. One is that multimedia splitting can improve the overall network performance (e.g., the permitted multimedia sessions or the aggregated bandwidth) while still keeping an acceptable media quality. The other is an adaptation capability to varying link quality. It has been widely investigated under various radio conditions and different monitoring intervals. It is shown that the adaptive technique is effective under dynamic radio environments.