Multi(six)-port impulse ultra-wideband radio system

Ultra-wideband (UWB) technology has attracted the interest of research institutions and the industry due to its numerous advantages such as low probability of interception and the possibility of combining data communication with positioning in a single system. Previous studies have shown that six-port technology can be used for single carrier communications and has several advantages such as wideband operation, low cost, and simplicity. The objective of this project is to study the multi(six)-port technology for impulse-UWB communications. In this thesis, original contributions are made on a multi(six)-port impulse radio (MIR) system including ultra-wideband six-port modulator, demodulator, novel phase spectrum modulation (PSM) schemes, and signal processing algorithms. Simulation and experimental results have been obtained and are presented in this thesis.; A MIR platform operating over a limited bandwidth of 1 GHz has been designed and implemented with commercial components. The MIR was used to validate wide band (3GHz-4GHz) new binary phase spectrum modulation (BPSM) and quaternary phase spectrum modulation (QPSM) schemes using wideband six-port modulator and demodulator circuits. Due to the lack of a monocycle generator, the 1-GHz spectral phase channel is generated from a rectangular pulse signal, upconverted using filters, mixer, and local oscillator. The 3-4GHz pulsed signal is applied to the RF input of a six-port modulator and digital data is simultaneously fed to a switch matrix terminating four ports of the new modulator with either a short circuit or open circuit. This technique produces an output RF signal in BPSM or QPSM scheme. At the receiver, one input port of the six-port demodulator is fed with the RF phase modulated signal and the second input port is fed with a reference non-modulated signal. The demodulator's four outputs provide signals of different amplitudes, which are used by a DSP to determine the modulation state with proper digital signal processing (DSP) algorithms. Modulation, demodulation algorithms and synchronization control are implemented on a field-programmable gate-array (FPGA) based DSP platform fitted with four analog-to-digital converters (ADCs). Assuming an additive white Gaussian noise (AWGN) channel, the proposed MIR was first simulated with the advanced design system (ADS) software tool of Agilent Technologies. The test bench version was then used for bit error rate (BER) measurements with both wired and wireless AWGN channels. A data rate of 20 Mbps was used for this measurement in conformity with the available instruments. The measured BER results have been successfully compared with simulation and theoretical results. Also other factors degrading the system performance, such as signal interference and multipath propagation were investigated and mitigation methods have been proposed. The MIR UWB is able to coexist with exiting radio system although it raises the noise floor to a certain degree. A brief comparison with other UWB systems is also given.; In future, a single integrated MIR UWB prototype is expected to accommodate both impulse-UWB and multi-band UWB standards.