Research On Seamless Handover And Related Technology In UMA

Current trend on development of wireless technology indicates that traditional GSM network and emerging new technology like WLAN and Bluetooth are all becoming maturity on their voice service. Nevertheless, when UMA (Unlicense Mobile Access) comes into the world, all the people will benefit from its seamless handover between GSM and WLAN voice call.Firstly, the writer gives a general introduction on the UMA network architecture to show how client end and server end devices work and how seamless handover happens. Based on the good comprehension of UMA technology, the writer implements a kind of UMA client end devices in both hardware and software.Then, focusing on the coexistence-interference of different wireless technology embedded in one mobile host, the writher did much analysis and handled the coexistence issue among GSM, WLAN and Bluetooth.Thirdly, UMA spec never takes care of seamless roaming within WLAN networks. By researching on current WLAN network, we introduce our solution so called "AP Pre-Forward", which could deploy the pre-forwarding data scheme between APs for roaming Mobile Station.Finally, based on DCF (Distributed Coordination Function, based on carrier sense multiple access with collision avoidance) and PCF (Point Coordination Function, contention-free protocol) we calculate out the capability of WLAN networks.