MobiPADS++: A Mobile QoS Middleware based on Hierarchical Fuzzy Control

Computation and networking resources in mobile operating environments are much scarcer and more dynamic than in desktop operating environments. Mobile applications require the benefits of adaptive computing to optimize the QoS management of dynamic contextual situations. Fuzzy control models have been successfully applied to various distributed network QoS managements systems. However, these models are either application-specific or limited to abstract modeling and simple conceptual scenarios that do not take into account overall model scalability. Specifically, the large number of QoS parameters in mobile operating environment causes the rule-explosion problem, in which an exponential increase in the number of rules increases the demand for processing power to infer the rules. Hierarchical fuzzy systems were introduced to reduce the number of rules using hierarchical fuzzy control, in which correlated linguistic variables are hierarchically inferred and grouped into abstract linguistic variables which can then be used as input for higher level fuzzy rules. In this paper, we propose a mobile QoS management framework that uses a hierarchical fuzzy control model to support a highly extensible and uncomplicated adaptation paradigm. This framework makes use of the synergy between mobile operating environments, mobile services and mobile applications, produces optimal system performance and satisfies the QoS needs of individual mobile applications.