Feedback-based traffic splitting for wireless terminals with multi-radio devices

It is expected that a number of heterogeneous radio access technologies will be available simultaneously at a single wireless terminal in next generation wireless networks. This paper addresses the challenge of link aggregation in a wireless terminal with multi-radio devices. A major issue in multi-path transmission is how to reduce the additional reordering delay at the receiver, which is mainly caused by the difference between link delays. This is particularly critical in wireless environments due to dynamics in link quality. Motivated by this observation, we propose a feedback-based technique to determine split ratios adaptively, based on measurements at the receiver. The link-level packet delay is measured on a periodic basis. The measurement is conveyed to the sender, and is used for split ratio calculation. The proposed technique has been implemented into an actual test-bed network which includes WiMAX and WiFi systems, and its potential usefulness is extensively evaluated. It was experimentally verified that for given radio link conditions, the traffic split ratio between WiMAX and WiFi links is optimally converged