The handover speed is always vital for the further development of Wireless Local Area Network (WLAN), which is enjoying a fast growth. Based on the handover technology specified in IEEE 802.11 WLAN, Manageable Fast Ha...The handover speed is always vital for the further development of Wireless Local Area Network (WLAN), which is enjoying a fast growth. Based on the handover technology specified in IEEE 802.11 WLAN, Manageable Fast Handover (MFHO) mechanism is proposed to speed up handover at the Access Point (AP), meet handover demands of services with different Quality of Service (QoS), and ensure service continuity. Adopting a handover policy named 'Make-before-break', this mechanism enables wireless APs to control and manage handover between two stations based on improving Inter-Access Point Protocol (IAPP). Tests have been carried out to compare functions and performance of MFHO and IAPP-based handover technology. The test results prove that MFHO provides a higher successful handover ratio and better handover performance than IAPP-based handover technology.展开更多
Hierarchical Mobile IPv6 (HMIPv6) can reduce the delay and the amount of signaling during handover compared with the basic mobile IPv6. However, the protocol still cannot meet the requirement for traffic that is delay...Hierarchical Mobile IPv6 (HMIPv6) can reduce the delay and the amount of signaling during handover compared with the basic mobile IPv6. However, the protocol still cannot meet the requirement for traffic that is delay sensitive, such as voice, especially in macro mobility handover. Duplicate address detection and the transmission time for the handover operation could cause high handover delay. This paper proposes a new mechanism to improve the fast handover algorithm's efficiency in HMIPv6 network. And we present and analyze the performance testing for our proposal by comparing it with the traditional HMIPv6 fast handover algorithm. The results of simulation show that our scheme can reduce the handover delay much more than the traditional fast handover method for HMIPv6 network.展开更多
The network-centric applied research team (N-CART) is continuing its work on an ambitious project known as the network-enabled powered wheelchair adaptor kit (NEPWAK). It introduces techniques for modifying and using ...The network-centric applied research team (N-CART) is continuing its work on an ambitious project known as the network-enabled powered wheelchair adaptor kit (NEPWAK). It introduces techniques for modifying and using powered wheelchairs as mobile platforms enabling communication and remote control. The wheelchair is equipped with a laptop computer, a CCD camera and a wireless network interface card (NIC) for 802.11b Internet access. The laptop acts as a server allowing network clients to gain access through a custom control interface on the chair. The remote controlling client receives a video and audio feed from the chair and sends control signals for maneuvering. While traveling, the chair is able to change its network association from one access point (AP) to another within the same subnet-the process is known as handoff. However, there is no inter-network handoff mechanism presently available in IP networks. This restricts the mobility of the wheelchair to within the coverage area of the subnet APs. This paper shows that the Internet engineering task force’s (IETF) network layer mobility protocol—Mobile IP suffers from large handoff latencies that can hinder communication between the client and the wheelchair during handoff. Mobile IP alone is not a sufficient solution for a mobile telebotic system such as NEPWAK. An interesting solution to the handoff latency problem comes from the Fast-handover protocol described in Section 4.4 with simulation results in Section 6.2.展开更多
文摘The handover speed is always vital for the further development of Wireless Local Area Network (WLAN), which is enjoying a fast growth. Based on the handover technology specified in IEEE 802.11 WLAN, Manageable Fast Handover (MFHO) mechanism is proposed to speed up handover at the Access Point (AP), meet handover demands of services with different Quality of Service (QoS), and ensure service continuity. Adopting a handover policy named 'Make-before-break', this mechanism enables wireless APs to control and manage handover between two stations based on improving Inter-Access Point Protocol (IAPP). Tests have been carried out to compare functions and performance of MFHO and IAPP-based handover technology. The test results prove that MFHO provides a higher successful handover ratio and better handover performance than IAPP-based handover technology.
文摘Hierarchical Mobile IPv6 (HMIPv6) can reduce the delay and the amount of signaling during handover compared with the basic mobile IPv6. However, the protocol still cannot meet the requirement for traffic that is delay sensitive, such as voice, especially in macro mobility handover. Duplicate address detection and the transmission time for the handover operation could cause high handover delay. This paper proposes a new mechanism to improve the fast handover algorithm's efficiency in HMIPv6 network. And we present and analyze the performance testing for our proposal by comparing it with the traditional HMIPv6 fast handover algorithm. The results of simulation show that our scheme can reduce the handover delay much more than the traditional fast handover method for HMIPv6 network.
文摘The network-centric applied research team (N-CART) is continuing its work on an ambitious project known as the network-enabled powered wheelchair adaptor kit (NEPWAK). It introduces techniques for modifying and using powered wheelchairs as mobile platforms enabling communication and remote control. The wheelchair is equipped with a laptop computer, a CCD camera and a wireless network interface card (NIC) for 802.11b Internet access. The laptop acts as a server allowing network clients to gain access through a custom control interface on the chair. The remote controlling client receives a video and audio feed from the chair and sends control signals for maneuvering. While traveling, the chair is able to change its network association from one access point (AP) to another within the same subnet-the process is known as handoff. However, there is no inter-network handoff mechanism presently available in IP networks. This restricts the mobility of the wheelchair to within the coverage area of the subnet APs. This paper shows that the Internet engineering task force’s (IETF) network layer mobility protocol—Mobile IP suffers from large handoff latencies that can hinder communication between the client and the wheelchair during handoff. Mobile IP alone is not a sufficient solution for a mobile telebotic system such as NEPWAK. An interesting solution to the handoff latency problem comes from the Fast-handover protocol described in Section 4.4 with simulation results in Section 6.2.
