Study on the Ultra-wideband Wireless Positioning Protocol Based on Pseudo-random Turnaround Delay

Ultra-Wideband (UWB) technology is considered to be the most suitable technology to indoor wireless location technology and IEEE 802.15.4a is the first physical layer standards used for wireless ranging and positioning in IEEE. There is no malicious network equipment in ideal circumstances, but there are snoopers, impostors and jammers in reality. There are authentication and encryption supports in the data link layer or network layer in some communication standards such as Wi-Fi, IEEE 802.15.4 and 802.11, but security rarely is considered in the physical layer and MAC sub layer. Ranging can be done based on just the Preamble and SFD (Start of Frame Delimiter), so malicious network devices can get the position of attack target just in the physical layer. This shows that the security of the physical layer is very important in ranging and positioning which is different from the protocol for information exchange. To provide a secure location services, this article presents a protocol based on pseudo-random turnaround delay. In this protocol, each target node delays different turnaround time, and then the attacker cannot determine the location of the target node.