Abstract
Collaborative beamforming (CBF) is a promising technique aimed at improving energy efficiency of communication in wireless sensor networks (WSNs) which has attracted considerable attention in the research community recently. It is based on a fact that beampattern with stable mainlobe can be formed, if multiple sensors synchronize their oscillators and jointly transmit a common message signal. In this paper, we consider application of CBF with one bit of feedback in different communication scenarios and analyze the impact of constraints imposed by simple sensor node hardware, on the resulting signal strength. First, we present a CBF scheme capable of reducing interference levels in the nearby WSN clusters by employing joint feedback from multiple base stations that surround the WSN of interest. Then, we present a collaborative power allocation and sensor selection algorithm, capable of achieving beamforming gains with transmitters that are not able to adjust their oscillators' signal phase. The performance of the algorithms is assessed by means of achieved beamforming gain which is given as a function of algorithm iterations. The presented results, which are based on numerical simulations and mathematical analysis, are compared with the ideal case without constraints and with negligible noise at the Base Station (BS).
Highlights
Wireless sensor networks (WSN), which are seen as one of the main pillars of the future Internet of Things (IoT), have attracted considerable interest in the research community
CONTRIBUTIONS In this paper, we present two extensions of CBF with one bit of feedback algorithm proposed by Mudumbai et al [8] in different communication scenarios, with constraints imposed by simple sensor node hardware, and analyze their impact on the resulting signal strength: 1) Collaborative beamforming with sidelobe control (CBF-SC) in a scenario where multiple Base Station (BS) are surrounding the wireless sensor networks (WSNs) of interest, which was originally presented in [24]
NUMERICAL RESULTS AND DISCUSSION we present the results of computer simulations with the aim of illustrating the behavior of the aforementioned CBF schemes
Summary
Wireless sensor networks (WSN), which are seen as one of the main pillars of the future Internet of Things (IoT), have attracted considerable interest in the research community. WSNs, which are formed by multiple sensor nodes, are capable of measuring different phenomena in their surroundings and sending their observations to a remote Base Station (BS), where the measurements are analyzed. With potentially large WSNs consisting of many sensor nodes, which are often deployed across large remote areas, energy consumption becomes one of the main. This constraint becomes even more severe, since often, frequent battery replacement is very costly and in some cases even not feasible. For simple lowcost sensor nodes, which have constrained computational capabilities, wireless data transmission to the remote BS consumes most of the available energy. One approach to the optimal usage of the available energy for the wireless communication link would be to use a transmitter with multiple antennas and direct most of the irradiated energy towards the BS. This, would require more costly sensor nodes with more processing power and complex RF chain, which often is not feasible
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