1,026 research outputs found
Channel Estimation for Ambient Backscatter Communication Systems with Massive-Antenna Reader
Ambient backscatter, an emerging green communication technology, has aroused
great interest from both academia and industry. One open problem for ambient
backscatter communication (AmBC) systems is channel estimation for a
massive-antenna reader. In this paper, we focus on channel estimation problem
in AmBC systems with uniform linear array (ULA) at the reader which consists of
large number of antennas. We first design a two-step method to jointly estimate
channel gains and direction of arrivals (DoAs), and then refine the estimates
through angular rotation. Additionally, Cramer-Rao lower bounds (CRLBs) are
derived for both the modulus of the channel gain and the DoA estimates.
Simulations are then provided to validate the analysis, and to show the
efficiency of the proposed approach.Comment: 5 figures, submitted to IEEE Transactions on Vehicular Technology, 29
March, 201
Improved Signal Detection for Ambient Backscatter Communications
In ambient backscatter communication (AmBC) systems, passive tags connect to
a reader by reflecting an ambient radio frequency (RF) signal. However, the
reader may not know the channel states and RF source parameters and can
experience interference. The traditional energy detector (TED) appears to be an
ideal solution. However, it performs poorly under these conditions. To address
this, we propose two new detectors: (1) A joint correlation-energy detector
(JCED) based on the first-order correlation of the received samples and (2) An
improved energy detector (IED) based on the p-th norm of the received signal
vector. We compare the performance of the IED and TED under generalized noise
modeled using the McLeish distribution and derive a general analytical formula
for the area under the receiver operating characteristic (ROC) curves. Based on
our results, both detectors outperform TED. For example, the probability of
detection with a false alarm rate of 1% for JCED and IED is 14% and 5% higher,
respectively, compared to TED. These gains are even higher using the direct
interference cancellation (DIC) technique, with increases of 16% and 7%,
respectively. Overall, our proposed detectors offer better performance than the
TED, making them useful tools for improving AmBC system performance.Comment: This paper has got Major Revision by IEEE TGC
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