Performance Analysis of a High Data Rate Uwb-DTR System in Dense Multipath Channels (original) (raw)
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IET Communications, 2009
A novel weighted high data rate single-user ultra-wideband transmitted-reference (UWB-TR) system is proposed and its performance in log-normal slow fading channels is investigated, which has not been addressed before. This system employs a novel signalling scheme, which provides a nearly inter-symbol interference (ISI) free-channel response at the receiver and eliminates the need for equalisation. It also enhances the reference pulse quality by employing optimum power allocation. The performance of the proposed system is compared with that of the differential transmitted-reference (DTR) system in IEEE 802.15.3a Channel Model 1 (CM1) both analytically and via simulations by taking into account noise, log-normal slow fading, inter-path/pulse interference (IPI) and ISI. Both analytical and simulation results show that our system significantly outperforms the DTR one. It is shown that the proposed method is robust against small changes in both weighting coefficients and integration interval, whereas the UWB-DTR scheme is too susceptible to such changes in the integration interval.
AEU - International Journal of Electronics and Communications, 2012
Recently, a novel single-user weighted transmitted-reference (WTR) system has been proposed for high rate ultra-wideband (UWB) communications. The WTR system can achieve a superior performance in high data rates and is also robust to variations of both weight coefficient and integration interval. In this paper, a multi-access (MA) scheme is proposed for the WTR system and its performance assuming perfect power control at the receiver is evaluated over dense multipath channels at 114 Mbps in the presence of inter-block interference (IBI) for the first time. Closed-form representation of both synchronous and asynchronous MA scenarios are derived and validated by simulations, in the presence of noise and all interfering terms for the first time. Interfering terms are inter-path/pulse interference (IPaI/IPI), intersymbol interference (ISI), and IBI. It is shown that the proposed MA scheme can significantly improve the system performance in multiuser scenario. Moreover, the single user performance of the WTR system is compared to those of a full-Rake receiver, conventional transmitted-reference (CTR), and differential transmitted-reference (DTR) through theoretical analysis and computer simulations by averaging over 100 realizations of IEEE 802.15.3a Channel Model 1 (CM1) including slow fading in the presence of noise and all aforementioned interfering terms.
Performance analysis of transmitted-reference UWB systems with narrowband interference suppression
Wireless Communications and Mobile Computing, 2009
In this paper, we propose a receiver structure for transmitted-reference ultra-wideband (TR-UWB) systems with both narrowband interference (NBI) and inter-pulse interference (IPI) mitigation capabilities. The effects of additive white Gaussian noise (AWGN) and the IEEE 802.15.4a fading channel are also taken into consideration. We adopt band-stop filtering to suppress the NBI. For IPI, it is statistically removed by a sum-and-average process. Theoretical analysis is carried out to study the lower bound of the bit-error rate (BER) performance of the proposed receiver. Numerical results show that the proposed receiver is able to provide satisfactory performance and is robust to variations in the system design parameters. It is also observed that the proposed receiver is able to deliver good performance even when there is zero delay between the reference and data pulses, which can effectively double the system throughput.
High Rate Multiuser UWB Weighted-TR System in Dense Multipath Channels
2011
Recently, a novel single user weighted transmitted-reference (WTR) system has been proposed for high data rate ultrawideband (UWB) communications. The WTR system not only achieves a superior performance but also supports high data rates and is robust to variations of both weighting coefficient and integration interval. To benefit of these advantages in multiuser environments, in this paper, a novel multi-access (MA) scheme is proposed for the WTR system and its performance for equal power users is evaluated over realistic dense multipath channels at 114Mbps in the presence of inter-block interference (IBI) of all previous blocks for the first time. To the authors' best knowledge, the rate of 114Mbps is the highest rate considered in UWB-TR systems. Closed-form representation of both synchronous and asynchronous MA scenarios are derived and validated by simulations, taking into account noise, inter-path/pulse interference (IPaI/IPI), inter-symbol interference (ISI), and IBI. It is shown that the system using the proposed MA scheme significantly outperforms the system with no MA scheme. Moreover, the single user performance of the WTR is compared to those of a full-Rake receiver, conventional transmitted-reference (CTR), and differential transmitted-reference (DTR) both analytically and via simulation averaged over 100 perfect realizations of IEEE 802.15.3a Channel Model 1 (CM1).
Multiuser interference and inter-frame interference in UWB transmitted reference systems
2004 International Workshop on Ultra Wideband Systems Joint with Conference on Ultra Wideband Systems and Technologies. Joint UWBST & IWUWBS 2004 (IEEE Cat. No.04EX812), 2004
Adshad-In transmitted reference ultra-widebaod m -m v B ) systems and differential trmsmltted reference (TITR-UWB) systems, the performance b, bnider to noire, determined by Interference among pulrss due to the dispersive multipath radio channel (Interframe Interference). The mulnplr SCPLII ioterference Ir also heavily influeaced by multipath pmpaganon. As 1 fin1 step towards the aaalysb and opthlzatioo of such systems, this paper anslyles statirtlcslly the response of the pulse-pair correlators Including Integrate and dump circuitry, which are the brric bulldiog black of TR-UWB receive-, to d n h d and un-dadred pulse-pairs. Rerulta are given Ln terms of basic channel parameters Ub RMS delay spread and Rlraan K-factor. As an erimple for the appllcstloa of OYI analysis, we present P navel multiuser DTR-UWB system.
Equivalent system model and equalization of differential impulse radio UWB systems
IEEE Journal on Selected Areas in Communications, 2000
A discrete-time equivalent system model is derived for differential and transmitted reference (TR) ultra-wideband (UWB) impulse radio (IR) systems, operating under heavy intersymbol-interference (ISI) caused by multipath propagation. In the systems discussed, data is transmitted using differential modulation on a frame-level, i.e., among UWB pulses. Multiple pulses (frames) are used to convey a single bit. Time hopping and amplitude codes are applied for multi user communications, employing a receiver front-end that consists of a bank of pulse-pair correlators.
Optimal and Suboptimal Receivers for Ultra-wideband Transmitted Reference Systems
The optimal receiver for an ultra-wideband transmitted reference (UWB TR) system in a single user multipath environment is derived, based on knowledge of channel properties. The performances of this optimal receiver and other crosscorrelation receivers are analyzed and compared. The usual crosscorrelation receiver which is often used in UWB TR systems is shown to be suboptimal. In addition, an UWB differential transmitted reference (UWB DTR) system is also proposed and its performance is evaluated.
Performance Evaluation of Multiple-Access Dual-Pulse Transmitted Reference UWB Systems
2008 International Wireless Communications and Mobile Computing Conference, 2008
This paper studies the performance of dual-pulse transmitted-reference (TR) ultra wideband (UWB) systems in presence of multi-access interference (MAI). We derive an analytical expression of the channel-averaged signal-to-interference ratio (SIR) for a TR UWB receiver in two asynchronous scenarios, based on random time-hopping (TH) codes. The analytical results and numerical results are presented for illustration. We further show the impact of the chosen system parameters (e.g. symbol duration and delay hopping code) to better understand their influence on the multi-user performance.
Study of Transmitted Reference, Frequency-Shifted Reference and Code-Shifted Reference UWB Receivers
Ultra wideband (UWB) is based on transmission with very short pulses of low energy. The use of UWB technology will increase in the fields of wireless communication in the near future. The wider bandwidth of UWB technology has several advantages such as excellent penetration ability, multi-user support and high channel capacity. UWB has many applications due to its low power consumption, low cost and low interference. UWB poses design challenges for low power and low complex systems at wider bandwidth. For digital systems, it also requires high sampling rate and intensive computation to estimate gain and delay of multipath channel. In this paper, the performance of non-coherent transmitted reference (TR), frequencyshifted reference (FSR) and code-shifted reference (CR) systems are compared with the Wa l s h coded reference (CR) systems for single and multi-user for low data rates. The results show that CR shows better performance than T R a n d F S R i n b o t h s i n g l e u s e r a n d m u l t i u s e r e n v i r o n m e nt .
Resolving inter-frame interference in a transmit-reference ultra-wideband communication system
2006 IEEE International Conference on Acoustics Speed and Signal Processing Proceedings
Transmit-reference ultra-wideband (TR-UWB) systems are attractive due to their relatively low complexity at both the transmitter and the receiver. Partly, this is achieved by making restrictive assumptions such as a frame length which should be much larger than the channel length. This limits their use to low data rate applications. In this paper, we lift this restriction and allow inter-frame interference (IFI) to occur. We propose a suitable signal processing data model and corresponding receiver algorithms which take the IFI into account. The performance of the algorithms are verified using simulations.