DS-UWB indoor positioning system implementation based on FPGAs

In Ultra-Wideband (UWB) Local Positioning Systems (LPS), Inter-Symbol Interference (ISI), Multiple-Access Interference (MAI) and near-far effect are significant issues that can limit system performance. This paper presents a DS-UWB (Direct Sequence UWB) LPS based on FPGAs (Field-Programmable Gate Array) and on commercially available Radio-Frequency (RF) modules. In contrast to other DS-UWB LPS, which uses TDMA (Time Division Multiple Access) and base-band pulses with low-repetition frequency rates, the proposal uses QS-CDMA (Quasi-Synchronous Code Division Multiple Access) techniques with Loosely Synchronized (LS) spreading sequences. This allows to deal with ISI, MAI and near-far effect, as well as to use very large spreading sequences to increase the processing gain.