Research Of Technology About Vertical Handoff In Digital Oilfield Heterogeneous Wireless Networks

With the Wireless and mobile networks are witnessing a great success in recentyears, as well as the need for wireless and mobile communications has growntremendously, have increasingly demands for mobility．Future wireless systems areenvisioned as being heterogeneous in that they will include a combination of variouswireless access technologies. Vertical handoff is a critical problem for the handoffmanagement of these heterogeneous wireless and mobile networks. A significantchallenge for coordination is vertical handoff decision that ensures mobile users'seamless mobility and ubiquitous access to applications across heterogeneousnetworks.In this dissertation, at first, mobility management in heterogeneous networks isintroduced comprehensively and on this basis, a systematic summary of the verticalhandoff techniques development and research is showed. Then the vertical handoffalgorithm in heterogeneous network is described and analysed briefly. The nextsome of the representative oilfield network solutions are compared and thearchitecture of WLAN and WCDMA integration is introduced. At last, In order toimprove the throughputs of system and to reduce the 'Ping-Pong effect', a differentthreshold and AHP (Analytic Hierarchy Process) based TOPSIS (Technique forOrder Preference by Similarity to an Ideal Solution) vertical handoff algorithm(DTAT) is proposed for heterogeneous networks. The handover trigger and handoverdecision are considered for DTAT. The signal to interference plus noise ratio (SINR)difference between the target network and the current network is obtained by mobilestation (MS), and the SINR difference between the two networks is compared with apredefined trigger threshold for handover trigger. The weight relations of decisionelements are determined by eigenvalue method of AHP. Finally, TOPSIS algorithmis used to make decision according to the attribute matrix and weight vector. The MSgets the TOPSIS decision values of the target network and the current network, andselect the best network. In simulation, the results show that the proposed algorithmcan improve the performance of vertical handover according to the characteristics ofthe traffic by considering the relations of multiple attributions synthetically.