Expected capacity based handoff scheme for multimedia data in WLAN

Recently, there has been an increase in user interest in multimedia services, such as VoIP, using mobile stations equipped with the IEEE 802.11 Wireless Local Area Network (WLAN) module in fast moving environments like Vehicle Ad hoc Networks (VANETs). In order to provide mobility and guarantee bandwidth in a wide area, a handoff among access point (AP) is essential. However, the IEEE 802.11 handoff using hard-handoff may easily lose connection, and it wastes much time on recognizing the connection severance and channel search time of re-connection. Such a wasted time can cause problems for multimedia data transmission. In order to solve this problem, we use GPS information to calculate the expected capacity using location, direction, velocity and RSSI information, in advance. Therefore, we suggest a handoff algorithm that uses the expected capacity to guarantee bandwidth. We implemented the suggested algorithm and experimentally verified the performance of the algorithm.