Michael B. Ames

Zigbee-based intra-car wireless sensor networks: a case study

There is a growing interest in eliminating the wires connecting sensors to the microprocessors in cars due to an increasing number of sensors deployed in modern cars. One option for implementing an intra-car wireless sensor network is the use of ZigBee technology. In this article we report the results of a ZigBee-based case study conducted in a vehicle. Overall, the results of the experiments and measurements show that ZigBee is a viable and promising technology for implementing an intra-car wireless sensor network.

Potential for Intra-Vehicle Wireless Automotive Sensor Networks

We propose using a wireless network to facilitate communications between sensors/switches and control units located within a vehicle. In a typical modern vehicle, the most demanding sensor will require a latency of approximately less than 1 msec with throughput of 12 kbps. Further, the network will need to support about 15 sensors with this requirement. The least demanding sensor will require a latency of approximately 50 msec with data throughput rate of 5 bps and will need to support about 20 of these types of devices. Initial part of this paper gives an overview of the issues spanning several layers of the protocol stack. Then, we focus on the Medium access control (MAC) layer and derive necessary design parameters based on given network requirements. We evaluate the IEEE 802.15.4 standard with respect to its suitability for use in a prospective intra-vehicle wireless sensor network.

ZigBee-based Intra-car Wireless Sensor Network

Due to an increasing number of sensors deployed in cars, recently there is a growing interest in implementing a wireless sensor network within a car. In this paper, we report the results of packet transmission experiments using ZigBee sensor nodes within a car under various scenarios. The results of the experiments suggest that both Received Signal Strength Indicator (RSSI) and Link Quality Indicator (LQI) can only be used as a threshold-based indicator to evaluate the link quality - indicating poor link quality when dropping below a certain threshold. Preliminary experimental results show that a detection algorithm developed by the authors based on RSSI/LQI/error patterns and an adaptive strategy might increase the goodput performance of the link while improving power consumption of the radio.

Intra-vehicular Wireless Networks

Automotive wiring harnesses that provide the wiring infrastructure for electrical and electronic sub-systems inside vehicles have grown in size over the years. Significant engineering challenges are posed due to increased weight/decreased fuel economy, increase in production steps, increased cost and labor in harness manufacturing and installation, increased design complexity, etc. wireless communications provides an intriguing alternative to wiring. This paper investigates the issues around replacing the current wired data links between electrical control units (ECU) and sensors/switches in a vehicle, with wireless links. We present a wide range of engineering issues and discuss potential solutions. We also provide recommendations with regard to future wireless intra- vehicular networks. Specifically, we provide a discussion on limitations and opportunities, based on simulation results, for network operations over an IEEE 802.15.4 stack protocol.