Real-Time Analysis and Design of a Dual Protocol Support for Bluetooth LE Devices

Modern distributed embedded systems frequently involve wireless communication nodes where messages have to be delivered within given timing constraints. This goal can be achieved by adopting a suitable real-time communication protocol. In addition, connecting such systems with mobile devices is also desirable for performing configuration, monitoring, and maintenance activities. The Bluetooth low energy (BLE) protocol would be an attractive solution for this purpose, because it is supported by consumer devices, such as tablets and smart phones, for implementing personal area networks with reduced energy consumption. Unfortunately, however, it cannot guarantee a bounded delay for managing real-time traffic. Modern BLE radio transceivers allow partitioning the network bandwidth between the BLE protocol and another user-defined protocol running on top of the raw radio. This paper exploits this feature to provide an analysis and a design methodology to guarantee the feasibility of a real-time custom protocol that shares the radio with the BLE. Experimental results on a Nordic reference platform show the feasibility of the dual-protocol approach and its capability to support a custom real-time protocol on the raw radio with a bounded overhead.