| Popis: |
In recent years, vertical handover (VHO) has been identified as the primary vehicle to provision seamless mobility and quality of service (QoS) transparency for end-user in composite network. This allows end-user to enjoy ubiquitous connectivity in the most efficient way, irrespective of time and place, commonly known as always best connected. In this chapter, the authors introduce the notion of cognitive cooperation as a means to provide optimized VHO opportunistically in order to exploit the inherent heterogeneity that exists within such composite network to improve radio resource usage. Through the cognitive cooperation, the chapter proposes a distributed load adaptation strategy (LAS) framework which exploits the benefits of joint optimization, particularly between link adaptation and load adaptation on-demand. The authors advocate that such synergetic interactions between the physical layer (PHY) and medium access control (MAC) layer have advantages over the PHY approach based only on link adaptation. Comprehensive performance analyses show that the LAS framework arbitrates a QoS-balanced system in which statistical QoS guarantee for multimedia traffic can be provisioned and overall system capacity can be maximized. |
