Characteristics of collaborative beamforming for wireless sensor networks in phase noise environments

Abstract

Collaborative beamforming has been widely used in wireless sensor networks to improve the directivity of signals in long-distance transmission. The performance of collaborative beamforming has been well analyzed for the case without phase offset in the literature. However, there always exists the phase ambiguity caused by carrier phase jitter between the transmitter and receiver nodes in a practical system. Although the effects of imperfect phase have been studied for Uniform node distribution and Tikhonov phase noise distribution, the performance analysis of collaborative beamforming with arbitrary node distributions and any phase offset is still an open issue. This paper proposes a unified method to evaluate the performance of collaborative beamforming in the case of phase noise. Since the non-parametric kernel method is used to build the probability density functions of node and phase offset distributions, the proposed nonparametric approach can provide accurate performance analysis for various node and phase noise distributions. The simulation results verify the proposed method.

Effect Analysis of Time and Carrier Frequency Offset on the Performance of Distributed Transmit Beamforming for Emergency Radio

“…We also compare the 3 dB width, 3 dB sidelobe region and normalized directivity, which are shown in Tables 1-3 As shown in Figures 6-9, while the average power level of the sidelobe remains unchanged at 1 N 10log 10 1 16 = −12 dB , the array gain at the desired direction is pulled down because of the offsets. As ρ increases, the corresponding TO and CFO increases, which leads to a larger degradation in the array gain.…”

“…Here we use Gaussian kernel method as shown in (7). This choice has been proved suitable to the performance analysis in [10].…”

“…The non-parametric kernel method in [9], [10] can estimate the PDF of z i for radio nodes distributions with or without explicit PDFs. Its basic procedure is to get an estimated PDF from a survey set.…”

“…It is an open issue to evaluate the effects of time and carrier frequency offsets on DTBF with arbitrary node distribution. Inspired by [9] and [10], this paper presents performance analysis of DTBF with arbitrary node distribution in presence of TO and CFO. The basic idea of this paper is to convert time and carrier frequency offsets into corresponding phase offset (PO) and then analyze their effects on beampattern properties in statistical way.…”

Congestion-Aware Routing and Fuzzy-based Rate Controller for Wireless Sensor Networks

“…In WSNs, some nodes (which are called sink nodes) are responsible for collecting data from other sensor nodes. For this reason, data collection is a crucial issue in WSNs [1,2]. In WSNs, routing is a very complex problem for a number of reasons.…”