Study Of Multi-AP Handover Algorithm Based On OFDMA For Next Generation WiFi

The wireless access technology allows people to be free from tedious physical connections, and gives people more freedom and flexibility. In a variety of wireless access techniques, the wireless network based on IEEE 802.11 has become the mainstream standard of wireless access techniques. It’s referred to as wireless fidelity (WiFi, Wireless Fidelity), designed for the short-range wireless communication, and especially the communication distance is generally 100m or less. In order to cover a relatively large area, it is necessary to lay a large number of wireless access points (AP, AccessPoint). In addition, because the current wireless LAN (WLAN, Wireless Local Area Network) has the disadvantages of limited coverage and imperfect voice services, it has not applied to the next generation of WiFi. The main work of this thesis is to research multi-AP handover algorithm based on OFDMA for next generation WiFi. The research project of this thesis comes from a national specialized key project on scientific technology, which is named "the technology verification and research of ultra high speed local area wireless network and its international standardization"(No:2012ZX030040 05-003).The main work is as follows:(1) Research multi-AP handover algorithm from the perspective of OFDMA resource reallocation to improve the system throughput and ensure the users’QoS.(2) Research the handover technology of WiFi network, and focus on the application of handover algorithm.(3) The objective is to propose a handover method to maximize system throughput and ensure the users’QoS.(4) Analyz the advantages and disadvantages of the traditional RSSI-based algorithm. Design handoff algorithms based on subcarrier and power redistribution with short scanning time, and the simulation results of the algorithms prove the superiority of the designed algorithms compared with the traditional algorithm.The thesis discusses the significance and research status of WiFi network handover technology. Based on the detail analysis of handover process and performance of the traditional IEEE 802.11 network, the thesis proposes the handover algorithm based on sub-carrier redistribution, handover algorithm based on power redistribution, and handover algorithm based on sub-carrier and power joint redistribution. By analyzing and comparing the performance, the simulation results show that the designed handover algorithms have short handover delay, and they can satisfy the needs of real-time applications such as VoIP, video streaming and so on.The development of the next generation of WLAN depends on broadband and high transmission rate. It will be used with cellular network complementary to provide a broad space for development.