End-to-end QoS guaranteed seamless handover scheme for cognitive heterogeneous networks

Roaming across heterogeneous wireless networks such as wireless wide area network (WWAN) and wireless local area network (WLAN) poses considerable challenges, as it is usually difficult to maintain the existing connections and guarantee the necessary end-to-end quality-of-service (QoS). This paper proposes a novel end-to-end QoS guaranteed seamless handover scheme, which can maintain the connections based on the end-to-end principle by incorporating an intelligent network status and environment detection mechanism. The proposed scheme consists of a new logical component, vertical handover manager (VHM). The VHM, by using application-layer, media access control-layer and physical-layer sensing techniques, can obtain accurate network condition and environment information, while at the same time reducing the unnecessary handover and ping-pong effect. Experiments have been performed to demonstrate the advantage of the proposed scheme.