Comparison of Vertical Handover Mechanisms Using Generic QOS Trigger for Next Generation Network

Next Generation Network (NGN) is envisage to integrate heterogeneous wireless systems. NGN is expectedto have Quality as the major challenging issue. More specifically, NGN aims at providing guaranteedQuality of Service (QoS) and Quality of Experience (QoE) i.e. what quality a network provider can offer(or claims) & what quality user experiences. NGN user may be interested in changing its network operatoror is forced to change the serving access point (AP) or base station (BS) in order to achieve a given levelof QoE. Seamless transfer of user’s service from existing operator to a new operator bearing dissimilarradio access technology is called Vertical Handover (VHO). VHO decision may depend on the popularsignal to noise ratio (SNR) criteria or other performance metrics like bit error rate, delay, jitter etc orcombination of these metrics. Performance of candidate target network depends on the type of traffic i.e.whether conversational, streaming, interactive or background is implemented. Therefore to optimise VHOmechanism, all these metrics & traffic types should be evaluated. Paper elucidates contemporary VHOapproaches i.e. hybrid ANP/ RTOPSIS & Oliver blume method. Different Interworking scenarios & NGNtestbeds are prepared considering Wi-Fi, WiMAX, UMTS etc. as the candidate networks. Neuro-fuzzybased MCDM weight assignment technique is applied & overall network cost function is computed basedon Qualnet simulation. At the end of the paper investigation suggests that Blume algorithm is better thanthe hybrid ANP mechanism because it is simple to implement, more efficient (40% more accurate), quicklycomputed (20 times less) and more dynamic (application oriented).