  With the emergence of connected and autonomous vehicles, sensors are
increasingly deployed within cars to support new functionalities. Traffic
generated by these sensors congest traditional intra-car networks, such as CAN
buses. Furthermore, the large amount of wires needed to connect sensors makes
it harder to design cars in a modular way. To alleviate these limitations, we
propose, simulate, and implement a hybrid wired/wireless architecture, in which
each node is connected to either a wired interface or a wireless interface or
both. Specifically, we propose a new protocol, called Hybrid-Backpressure
Collection Protocol (Hybrid-BCP), to efficiently collect data from sensors in
intra-car networks. Hybrid-BCP is backward-compatible with the CAN bus
technology, and builds on the BCP protocol, designed for wireless sensor
networks. Hybrid-BCP achieves high throughput and shows resilience to dynamic
network conditions, including adversarial interferences. Our testbed
implementation, based on CAN and ZigBee transceivers, demonstrates the load
balancing and routing functionalities of Hybrid-BCP and its resilience to DoS
attacks. We further provide simulation results, obtained with the ns-3
simulator and based on real intra-car RSSI traces, that compare between the
performance of Hybrid-BCP and a tree-based collection protocol. Notably, the
simulations show that Hybrid-BCP can achieve the same performance as the
tree-based protocol while reducing the radio transmission power by a factor of
10.
