A SIMO one-bit time reversal for UWB communication systems

Abstract

With the one-bit time reversal ultra wideband (OTR-UWB) transceiver, the data symbols are encoded using the reversed order of the channel phase. The major factor limiting SISO OTR capacity and performance is intersymbol interference (ISI). As the data rate goes up, the ISI becomes more severe and it degrades system performance and capacity. In this article, a new single input multiple output (SIMO) system is proposed for an OTR-UWB system. The proposed transceiver structure is based on spatial focusing property of OTR. The performance of the proposed SIMO OTR-UWB system is analyzed in terms of the signal-to-interference-plus-noise-ratio (SINR). It is shown that using a SIMO OTR transceiver, ISI is reduced and the system capacity is increased almost linearly with the number of received antenna. Transmitted signal power at SIMO OTR decreases therefore in low data rates, SISO performance is better than SIMO, but in high rate scenario, SIMO OTR suppresses ISI better than SISO OTR and its performance is better. It is possible to compensate the reduced power using a receiver with more sensitivity, but to compensate the ISI effects, an MMSE receiver or equalizer techniques should be used, since the computational complexity of MMSE receiver grows exponentially with channel length and equalizers reduce the efficient bit rate. It is shown that the proposed SIMO-OTR capacity linearly increases with the number of antennas and decreases logarithmic (almost linearly).

Performance of time reversal precoding technique for MISO-OFDM systems

“…Pioneer works of Paulraj et al have namely shown that the richer the scattering environment, the better the time and focusing gains [12]. In UWB systems for instance, TR is suitable as a simple and efficient prefiltering technique for pulse amplitude modulation [13][14][15] since it is realized over large frequency bandwidths. For systems addressing narrower bandwidths and hereby playing with less rich propagation conditions, the so-called rate back-off or oversampling strategies can be used to compensate for some focusing gain degradation [16,17].…”

Alamouti OFDM/OQAM Systems with Time Reversal Technique

“…Firstly experimented in acoustics and ultrasound domains [7] [8] [9], Time Reversal (TR) has also received attention recently for wireless communications [10] [11] [12]. Owing to its inherent time and spatial focusing properties, TR is now studied as a solution for future green wireless communications [12].…”

Spatiotemporal Focusing of Phase Compensation and Time Reversal in Ultrawideband Systems With Limited Rate Feedback

“…The effect of quantization error on the UWB transmit beamforming has been investigated to some extent by a few researchers [19][20][21]. They particularly study the TR beamforming performance when only the temporal phase information of the channel impulse response (the sign of each path gain) is provided on the transmitter side, a technique known as one-bit TR [19][20][21][22][23][24][25].…”

“…They particularly study the TR beamforming performance when only the temporal phase information of the channel impulse response (the sign of each path gain) is provided on the transmitter side, a technique known as one-bit TR [19][20][21][22][23][24][25]. The majority of these works are theoretical studies based on simplified models which do not consider important propagation phenomena like the frequency dependence of the MPC and path loss exponent [19][20][21]. For example in [19], Chang et al theoretically predict the performance of one-bit TR compared to the conventional TR technique, assuming a Rayleigh fading model holds for UWB channels.…”

“…They simulate the Bit-Error-Rate (BER) and the output signal to interference plus noise (SINR) performances at data rates of 25 Mbps and 50 Mbps. Abbasi-Moghadam [21] also evaluates performance of one-bit TR based on the Rayleigh channel fading assumption for single input multiple output systems. As explained in [26,27], Rayleigh fading is not a realistic propagation model for UWB systems with large bandwidth.…”