tailieunhanh - VoIP Technologies Part 13

Tham khảo tài liệu 'voip technologies part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Multi-path Transmission Selection and Handover Mechanism for High-Quality VoIP 291 MP cmpSCTP SP RTP--------MP SCTP a The new cell has smaller available bandwidth MP cmpSCTP -SP RTP------MP mSCTP I b The new cell has the same available bandwidth c The new cell has larger available bandwidth Fig. 8. Association throughput during handover 292 VoIP Technologies e MP cmpSCTP -ft-SP RTP------MP mSCTP Fig. 9. Impact of moving speed on handover latency. path is almost the same regardless of the moving speed. Therefore handover latency becomes larger as the moving speed becomes faster and the Latent Handover scheme always has the handover latency close to zero for all moving speeds which explained for Fig. 9. Until the speed of MH movement increases to the degree that MH s overlapping area transiting time is smaller than the new path acquisition time cmpSCTP will cause some amount of handover latency. 5. Conclusion In future wireless access networks CMT can enhance aggregating throughput and enable the network resource to be utilized efficiently. In this chapter we proposed a new cmpSCTP protocol to better support high-quality VoIP applications over heterogeneous wireless networks. The cmpSCTP keeps two or more end-to-end paths concurrent transferring new data from a source to a destination host. More sophisticated network deployments mean that there may be some topologically shared or joint links between different transport paths. Thus we propose a multipath selection strategy to exploit the path diversity by taking into account the potential path correlation. The probing and grouping mechanism can select the path set with minimum correlations thus enabling the subsequent selection to avoid underlying shared bottleneck. There is another demand for mobility between networks with maintained connectivity which requires the ability to switch the transmission path. Thus we discuss the issue of handover in heterogeneous wireless networks. Our simulation results demonstrate that