Transport Protocols over UMTS and its Evolutions - Performance Investigation and Enhancements

The UMTS networking protocol stack contains protocols that are concerned with the low level services provided by the cellular network, and higher layer protocol layers, i.e. transport and application layer protocols, have to run on top of them to complete the end-to-end data connection. One such option is to utilise protocols from the TCP/IP (Transmission Control Protocol/Internet Protocol) stacks, which are currently used on the Internet. However, these protocols were designed and optimised for wired networks, and they might not perform well if they are used in a wireless network because of the high block error rates, high processing delays, variable bandwidth, and asymmetry experienced in wireless networks. That is, though reusing existing TCP/IP protocol units will save a lot of work, an extensive investigation and tuning should be done with regard to their performance in conjunction with UMTS networks.The main objective of this project work is to investigate the performance of transport layer protocols over UMTS networks, considering the overall QoS (Quality of Service) required by the user; and to come up with methods to optimise their performance. Once the main bottlenecks have been identified, ways of optimising the performance of the system, either by tuning the transport protocols or the UMTS network, will be devised. The major determining factors for packet data transmission and their effect on the overall QoS of a service running on top of a UMTS network have been identified and a platform is developed where the effects of a UMTS network on packet data transmission will be emulated. Emulation is chosen so that real transport and application layers can be used, which in turn will make the evaluation more realistic. Also, usability studies can be performed as we can deal with real applications, such as streaming, running over the emulated network. Tests are being carried out to find out the effect of different protocol parameters on the QoS, and the emulation platform is being refined. (Oumer Teyeb, Preben E. Mogensen; Jeroen Wigard, Nokia)