Energy-aware QoS for application sessions across multiple protocol domains in mobile computing

The proliferation of heterogeneous devices and diverse networking technologies demands flexible models to guarantee the quality-of-service (QoS) at the application session level, which is a common behavior of many network-centric applications, e.g., Web browsing and Instant messaging. Several QoS models have been proposed for heterogeneous wired/wireless environments. However, we envision that the missing part, which is also a big challenge, is taking energy, a scarce resource for mobile and energy-constrained devices, into consideration. In this paper we propose a novel energy-aware QoS model, e-QoS, for application sessions that might across multiple protocol domains, which will be common in the future Internet, rather than an exception. The model provides QoS guarantee by dynamically selecting and adapting application protocols. To the best of our knowledge, our model is the first attempt to address QoS adaptation at the application session level by introducing a new QoS metric called session lifetime. To show the effectiveness of the proposed scheme, we have implemented two case studies: Web browsing from a Pocket PC to a regular Web server, and an instant messaging application between two Pocket PCs. In the former case study, our approach outperforms the conventional approach without energy-aware QoS by more than 30% in terms of the session lifetime. In the second case study, we also successfully extend the session lifetime to the value negotiated by two Pocket PCs with very diverse battery capacities. 2007 Elsevier B.V. All rights reserved.