Hybrid coherent and frequency-shifted-reference ultrawideband radio

Liu, H.; Molisch, Andreas F.; Goeckel, Dennis; Orlik, Philip V.

doi:10.1016/j.phycom.2009.06.003

Cited by 5 publications

(7 citation statements)

References 21 publications

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“…For each data point shown, 2000 channels are simulated. Four systems will be considered: the original FSR system [1], the improved FSR-2 system [12], the PPM system, and a test system termed PPM-2, for which:…”

Section: A Numerical Resultsmentioning

confidence: 99%

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A Class of Ultra Wideband (UWB) Systems with Simple Receivers

Goeckel

Mehlman

Burkhart

2007

MILCOM 2007 - IEEE Military Communications Conference

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Ultra-wideband (UWB) communication systems are of interest in many applications, including those that require accurate positioning and low data rate communications (e.g. IEEE 802.15.4a). However, UWB systems have been dogged by implementation concerns, particularly that of building the receiver in a small integrated fashion for extremely low-power devices. Thus, UWB systems with simple receivers are of interest. Candidate modulations for such include the burst-mode pulse-position modulation (PPM) being standardized in IEEE 802.15.4a, and the recently-introduced frequency-shifted reference (FSR) UWB scheme. Here, we show that, in the singleuser case, the FSR-UWB system can be modified in a very simple way to yield other systems that are also easy to implement. In particular, rather than employing a cosine for separating the data and reference signals (as we originally proposed in the FSR-UWB system), one can employ any waveform from a very large class for such. The resulting class is general enough to encompass FSR-UWB, PPM, and on-off keying (OOK), thus capturing all three of the commonly-considered UWB schemes that provide very simple receivers. We provide a performance characterization of systems in the class on both additive white Gaussian noise (AWGN) and multipath fading channels as a function of the waveform employed, thus allowing a unified performance comparison of not only the commonly considered systems listed above but also numerous other heretofore unconsidered systems. Optimization across this class can then be considered for various operating scenarios.

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Section: A Numerical Resultsmentioning

confidence: 99%

“…In [12], it is observed that the frequency of the FSR-UWB separating signal can be halved. Since the minimal frequency offset provides the best performance in a multipath fading channel [1], this is a desirable modification.…”

Section: Introductionmentioning

confidence: 99%

A Class of Ultra Wideband (UWB) Systems with Simple Receivers

Goeckel

Mehlman

Burkhart

2007

MILCOM 2007 - IEEE Military Communications Conference

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“…Assume the channel remains static during a data burst (say 100µs [8]) and CIR is available at the transmitter. How CIR is obtained is not a task of this paper.…”

Section: System Descriptionmentioning

confidence: 99%

“…Mainly due to potentially low implementation complexity, suboptimal reception strategies, such as transmitted reference (TR) [1]- [8] and its variants [9]- [13] as well as energy (or square law) detector [14]- [17], have received increasing attention for complexity and cost constrained wideband applications. These suboptimal schemes are of low-complexity in the sense that no channel estimation is required and they are less sensitive to timing error.…”

Section: Introductionmentioning

confidence: 99%

Waveform-level precoding with simple energy detector receiver for wideband communication

Guo

Saini

et al. 2009

2009 41st Southeastern Symposium on System Theory

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Wideband waveform-level precoding with simple energy detector receiver is investigated in this paper. The motivation is to provide a cheap radio network with simple receivers and sophisticated transmitters. The energy detector receiver performs relatively poorly, but waveform-level precoding can be used to compensate for the performance loss. Waveform-level precoding is a transmitter-side processing taking advantage of known channel information. Given channel impulse response (CIR), transmitted waveform can be optimized in some criterion. In this paper the optimization goal is to maximize an equivalent signal-to-noise ratio (SNR) at the receiver, assuming no inter-symbol-interference (ISI). Close-form expressions are derived based on the Park's empirical model for evaluating the receiver operating characteristic (ROC) of energy-detector. Numerical approach is adopted to handle continuous time signals. Channel data measured in office area is used to obtain numerical results. Performance comparison with time reversal precoding as benchmark shows that the optimal waveform can offer gains of several decibels.

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“…In fact, the simplicity allowed a team of University of Massachusetts undergraduates to build and demonstrate a low data rate FSR-UWB system on two small circuit boards [6]. Researchers have also extended methods developed for TR-UWB systems during the IEEE 802.15.4a standardization process to allow flexible receiver architectures to FSR-UWB [7]. Other researchers have started working on the multicarrier approach for FSR, both in digital [8], [9] and analog [10] domains.…”

Section: Introductionmentioning

confidence: 99%

Optimization of frequency-shifted reference ultrawideband systems

Joshi

Lai

Morrison

et al. 2008

2008 42nd Asilomar Conference on Signals, Systems and Computers

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Recently, there has been significant interest in developing ultrawideband (UWB) radio techniques. A transmitted reference (TR)-UWB technique is often considered for low-tomoderate data rate applications. However, the TR-UWB technique is limited by the difficulty in building the required highly accurate wideband analog delay line in the receiver. Frequencyshifted reference (FSR)-UWB avoids this analog delay by shifting the reference signal from the data signal in frequency, and FSR-UWB has been shown to outperform the standard TR-UWB scheme. The performance of the FSR-UWB system has been further improved in succeeding work by sending multiple data signals that share a common reference carrier, referred to as multi-differential (MD) FSR, but this comes with a significant increase in the peak-to-average power (PAPR) of the pulses. In this paper, three improvements are proposed for the FSR-UWB system: the front-end filter and the integration time at the receiver are optimized, and a PAPR minimization scheme for the MD-FSR scheme is introduced. After describing and characterizing these approaches, simulation results are provided to consider the varying degrees of improvement offered through the proposed techniques.

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Hybrid coherent and frequency-shifted-reference ultrawideband radio

Cited by 5 publications

References 21 publications

A Class of Ultra Wideband (UWB) Systems with Simple Receivers

A Class of Ultra Wideband (UWB) Systems with Simple Receivers

Waveform-level precoding with simple energy detector receiver for wideband communication

Optimization of frequency-shifted reference ultrawideband systems

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