Distributed Antenna System Using Concurrent Transmission for Wireless Automation System

This paper proposes to adopt concurrent trans- mission in a distributed antenna system to achieve the real- time capability and reliability for wireless automation systems. Our scheme is the simplest way to realize spatial diversity by deploying a large number, e.g. several tens, of transmit antennas and allow all of them to participate in simultaneous packet transmission without any cooperation. We examine the performance, including packet error rate and high- reliability area percentage, in simulation and over-the-air experiments under the IEEE 802.15.4 standard, where the experiments are conducted with up to 32 concurrent transmitters using Tmote Sky sensor nodes. We found that the presence of a timing offset limits the performance. By lowering the timing offset to be below half of a chip period, the reliable performance can be achieved without sacrificing the real-time capability.