Ranging Mechanism, Preamble Generation, and Performance with IEEE 802.15.4a Low-Rate Low-Power UWB Systems

Abstract

IEEE 802.15.4a Task Group is defining an ultra low power consumption and low cost radio for Wireless Personal Area Networks (WPANs) applications using Ultra-wideband (UWB) technology with high precision ranging capability. Ternary preamble sequences of two different lengths have been proposed and adopted in the IEEE 802.15.4a specification for ranging. In order for a IEEE 802.15.4a low cost UWB device to support multiple frequency bands across the available spectrum and ranging features, as many as twenty-four ternary sequences is required. A sizeable amount of memory is needed to store the codes. In this paper, we propose a method to generate the ternary codes using linear feedback shift registers (LFSRs) as and when it is required, resulting in significant memory savings. The ranging performance using the proposed ternary preamble sequence is evaluated through simulation.

A distributed newton iteration based localization scheme in underground tunnels

“…[3,4]. These potential applications of wireless positioning were also recognized by IEEE, which approved a new amendment, IEEE 802.15.4a, that provides a new physical layer for low data rate communications combined with positioning capabilities [5,6].…”

“…RF TOF ranging occurs in short bursts and in a frequency hopped fashion thereby reducing the chance of interference. RF-TOF ranging is such an attractive option for WSNs that some prototypes have been demonstrated, but work has been largely limited to wide bandwidths and high power devices [22].Optimization of RF-TOF for WSNs has recently received attention with some interesting results in the wideband signal domain [6]. In bandwidth limited systems, measuring the TOF requires accurately resolving the phase offset of a signal.…”

Maximal operating distance estimation for ranging in IEEE 802.15.4a Ultra Wideband

“…In contrast to the coherent receiver the non-coherent receiver uses a different despreading code than the spreading code, which shows also perfect circular correlation properties for the squared sequences. The despreading codec is created by squaring c and setting all zeros to −1 [2]. As observable, the output of the energy detector is dependent on a signal-by-signal y ss [n], a linear signal-by-noise y sν [n] and a quadratic noise-by-noise y νν [n] term.…”

“…The standard allows the usage of high complexity coherent receivers and low-complexity energy detectors. The used preamble sequences show perfect autocorrelation properties for both receiver types [2].…”

“…The standard allows the usage of high complexity coherent receivers and low-complexity energy detectors. The used preamble sequences show perfect autocorrelation properties for both receiver types [2].Energy detectors promise low-cost and low-power consumption. On the other hand, a performance loss [3] and more vulnerability to interfering signals occur [4].…”