Low-Sampling-Rate Ultra-Wideband Channel Estimation Using Equivalent-Time Sampling

Abstract

In this paper, a low-sampling-rate scheme for ultra-wideband channel estimation is proposed. The scheme exploits multiple observations generated by transmitting multiple pulses. In the proposed scheme, pulses are transmitted to produce channel impulse response estimates at a desired sampling rate, while the ADC samples at a rate that is times slower. To avoid loss of fidelity, the number of sampling periods (based on the desired rate) in the inter-pulse interval is restricted to be co-prime with . This condition is affected when clock drift is present and the transmitted pulse locations change. To handle this case, and to achieve an overall good channel estimation performance, without using prior information, we derive an improved estimator based on the bounded data uncertainty (BDU) model. It is shown that this estimator is related to the Bayesian linear minimum mean squared error (LMMSE) estimator. Channel estimation performance of the proposed sub-sampling scheme combined with the new estimator is assessed in simulation. The results show that high reduction in sampling rate can be achieved. The proposed estimator outperforms the least squares estimator in almost all cases, while in the high SNR regime it also outperforms the LMMSE estimator. In addition to channel estimation, a synchronization method is also proposed that utilizes the same pulse sequence used for channel estimation.

Low-Complexity Bayesian Estimation of Cluster-Sparse Channels

“…It is found that for sparsity rates of 0.1 or less, threshold values in the interval 2-4 σ v yield excellent cluster detection in most cases. 3 Note that α is not confined to integer values. The values given are just examples.…”

“…C HANNEL impulse response estimation is an important wireless communications topic that finds applications in wireless radio communications [1]- [3], underwater acoustic commutations [4]- [6], as well as in SONAR and radar systems [7,8]. The literature is rich in methods that can be applied to estimate a channel impulse response.…”

Enhancing the Bitrate and Power Spectral Density of PPM TH-IR UWB Signals using a Sub-Slot Technique

“…Various modulation techniques, such as Pulse-Amplitude Modulation (PAM), Pulse-Interval Modulation (PIM), Pulse-Shape Modulation (PSM), Pulse-Position Modulation (PPM), On-Off Keying (OOK), and Bi-Phase Shift Keying (BPSK), are used to transmit the information in such systems [2,3]. In PPM, the information is determined by the position of one pulse [4].…”

Low-complexity WLMMSE channel estimator for MB-OFDM UWB systems

“…In the UWB literature, the channel estimation has mostly been studied for its effect on error rate performance and computational complexity [8][9][10][11][12][13][14][15][16][17][18]. For example, a minimum mean square error (MMSE) estimator has been proposed by Beek et al, and they have shown that it gives a performance gain over least square (LS) estimator [8].…”

“…Moreover, Li et al have proposed a low-complexity channel estimator developed by first averaging the overlap-added (OLA) received preamble symbols within the same band and then applying time-domain least squares method followed by the discrete Fourier transform [9]. Also, a low-sampling-rate scheme, based on multiple observations generated by transmitting multiple pulses, for ultra-wideband channel estimation has been proposed in [12]. Furthermore, authors in [18] propose preamble-based improved channel estimation in the presence of both multiple-access interference (MAI) and narrowband interference (NBI).…”