Abstract
In this paper, we pay our attention towards the noncoherent demodulation aspect of binary phase shift keying (BPSK) receivers for IEEE 802.15.4 wireless sensor networks (WSNs), and a carrier frequency offset invariant as well as error-floor free multiple-symbol differential detection (MSDD) strategy is proposed over the flat fading channel. This detector is an alternative to the multiple-symbol detector that has been considered almost exclusively in the past. In this new configuration, the receivers do not perform chip-level precompensation as in conventional scheme but bit-level postcompensation. That is, the bit-level autocorrelation operation is first implemented with the “raw” chip sample, and then the carrier frequency offset effect (CFOE) embedded in the achieved statistic is compensated. Correspondingly, the cumulative error in the detection metric is decreased so much that the pervasive error floor for the conventional MSDD scheme is suppressed. Also, complexity efficient estimators for the MSDD scheme are reinvestigated, analyzed, and summarized. Simulation results demonstrate that this new detection strategy may achieve rather more encouraging gain from differential and spread spectrum coding than the conventional single differential coherent detection (SDCD) scheme. The pervasive error floor is also eliminated as compared with conventional MSDD scheme even if the most simple estimator is configured under large bit observation length. Then, much transmitting energy may be saved for each chip symbol, which is practically desired for transmit-only nodes in WSNs.
Highlights
Recent years have witnessed much concentration on pervasive wireless sensor networks (WSNs), especially because of its wide application potentiality in the future “Internet of ings (IoT)” for the “edge access” [1,2,3,4,5]
As shown in [15], in conventional multiple-symbol di erential detection (MSDD) algorithm, carrier frequency o set e ect (CFOE) is marginalized out with chip-level compensation with an external estimator prior to the bit-level autocorrelation operation. is external estimator is activated only once before each packet detection, and it can provide an initial estimate of the unknown CFOE
We perform the simulation over a complex additive white Gaussian noise (AWGN) channel or a slow Rayleigh fading channel and give
Summary
Recent years have witnessed much concentration on pervasive wireless sensor networks (WSNs), especially because of its wide application potentiality in the future “Internet of ings (IoT)” for the “edge access” [1,2,3,4,5]. Motivated by the aforementioned observations and to achieve much more performance improvement from differential encoding and energy saving for the transmit-only node [13, 14], in this work, we restrict our attention towards developing a multiple-symbol differential detection (MSDD) scheme for the receiver in the sink node. The main contribution is that a simple and robust MSDD scheme without error floor is improved for BPSK receivers in sink nodes of WSNs. Especially, we are extending and modifying the previous work [15] mainly in four aspects as follows:. The proposed MSDD scheme may be tailored for uncoded or coded M-ary DPSK receivers Such analyses, will be under investigation in our future work.
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