Digital Weighted Autocorrelation Receiver Using
Channel Characteristic Sequences for Transmitted
Reference UWB Communication Systems
Zhonghua Liang
1,2
, Xiaodai Dong
2
, Xiaojun Yang
1
, and Huansheng Song
1
1
School of Information Engineering, Chang’an University, Xi’an 710064, P. R. China
Email: lzhxjd@hotmail.com, {xjyang,hshsong}@chd.edu.cn
2
Department of Electrical and Computer Engineering, University of Victoria, Victoria, BC V8W 3P6, Canada
Email: {xdong}@ece.uvic.ca
Abstract—Weighted autocorrelation receivers have been pro-
posed in the literature to suppress noise or interference for
transmitted reference ultra-wideband communication systems.
Usually weight optimization is performed for partitioned integra-
tion bins. To improve the optimization effect, this paper proposes
a digital weighted autocorrelation receiver, in which the sampled
auto-correlated signal is first rearranged following a channel
characteristic vector that sorts the strengths of the received
channel samples, and then it is divided into multiple partitions.
Finally, the integration bins corresponding to these partitions are
weighted according to the minimum mean square error principle.
Results show that compared to the digital versions of existing
weighted autocorrelation receivers, the proposed digital scheme
can achieve significantly better bit error rate performance with
limited penalty in terms of implementation complexity.
Index Terms—autocorrelation receiver, transmitted reference,
ultra-wideband, weight optimization, bit error rate.
I. INTRODUCTION
T
RANSMITTED reference (TR) signaling in conjunction
with autocorrelation receiver (AcR) has become one of
the two popular noncoherent ultra-wideband (UWB) systems
(the other popular scheme is the noncoherent UWB system
with energy detector) due to its simplicity and robust per-
formance [1]. For the original AcR, because of the nature of
clustered and dispersive energy distribution in dense multipath
propagation environments, considerable noise-dominated por-
tions of the received signal are involved in the autocorrelation
operation even though the integration interval has been opti-
mized, and that inevitably results in a significant performance
loss.
To mitigate the noise effect, the concept of weighted
AcR (W-AcR) was first proposed in [2], where the original
autocorrelation operation was replaced by a linear optimal
combination of specific parts of the auto-correlated signal.
This work was supported in part by the Natural Sciences and Engineering
Research Council of Canada (NSERC) under Grant 261524-2003, in part
by the National Natural Science Foundation of China (NSFC) under Grant
61271262, 61473047, 61572083, and 61201233, in part by Shaanxi provincial
natural science foundation under Grant 2015JM6310, and in part by the
Special Fund for Basic Scientific Research of Central Colleges, Changan
University (310824152010 and 0009-2014G1241043).
Accordingly, two methods were presented in [2] to divide
the auto-correlated signal within the integration interval into
specific subsections for linear combining. The first method
splits the auto-correlated signal based on its amplitude distri-
bution and forms multiple subsections labeled with equally-
spaced amplitude levels (ESAL). The other scheme divides
the auto-correlated signal along with the integration interval
and generates different portions corresponding to uniformly
partitioned integration bins (UPIB). The results reported in
[2] show that the UPIB-W-AcR significantly outperforms the
ESAL-W-AcR. Moreover, the ESAL-W-AcR requires an ideal
channel-dependent parameter as an indication of the maximum
amplitude, and hence this makes it infeasible.
The UPIB-W-AcR has been further developed to suppress
noise or interference [3]–[6]. Meanwhile, in another popular
noncoherent UWB system using binary on-off keying (OOK)
modulation or pulse position modulation (PPM), UPIB-based
weighted energy detectors (WEDs) were also widely investi-
gated to address similar issues [7]–[10].
However, even with the popular UPIB-based schemes, it is
still possible that both signal-dominated and noise-dominated
components are inside in the same integration bin, due to the
limited time resolution of integration bins and the dispersive
energy distribution in multipath channels. In this case, for
those bins that contain significant signal components as well
as considerable portions of noise, the same weights will be
applied to both the signal and the noise components, and
therefore the overall optimization will be intractable.
On the other hand, recent works on digital architectures for
UWB systems [11]–[18] show that reduced complexity digital
receivers, such as monobit or finite-resolution digital receivers,
can achieve satisfactory bit error rate (BER) performances
approaching that of the full-resolution digital implementations.
These achievements pave the way to develop feasible digital
receivers for UWB applications with low cost, low power
consumption and low complexity, as well as making full use
of the flexibility of digital signal processing (DSP).
In this paper, we propose a digital W-AcR design, where
the sampled auto-correlated signal is first rearranged into
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