Analysing and reducing network inaccessibility in IEEE 802.15.4 wireless communications

Network inaccessibility is a temporal issue derived from the presence of faults affecting the communication services provided by the medium access control (MAC) sublayer. The occurrence of network inaccessibility represents temporary “communication blackouts”, which prevent communications to be performed and may imply disruptions of network operation, therefore compromising the dependability and timeliness of communications. This paper uses an analytical model accounting for network inaccessibility periods in wireless sensor and actuator networks, presenting the IEEE 802.15.4 standard as a case study. The analytical model is then used to derive a set of simple, yet quite effective policies to reduce the durations of the periods of network inaccessibility. The effectiveness of these policies can be evaluated using a tool based on the analytical model, which is being integrated in the NS-2 simulator for validation. Reducing network inaccessibility is a crucial step to enable the use of wireless networking technologies in real-time settings.