ElasticWISP: Energy-Proportional WISP Backhaul Networks

<p>The provision of rural broadband infrastructure is a challenge for network operators across the globe, irrespective of their size. Wireless Internet Service Providers (WISPs) have shown that the small-scale deployment of wireless broadband infrastructure is a viable alternative to relying on cellular network providers for remote coverage. However, WISPs must often resort to using off-grid renewable energy sources such as solar energy for powering network sites, often resulting in undesirable, low-performance backhaul radios being used between sites out of concern for excessive energy consumption. The challenges of managing performant wireless backhaul networks in respect to energy constraints at remote, off-grid sites informs the need for energy-proportional design. Backhaul radios typically used by WISPs are not energy-proportional, meaning they use a consistent amount of energy, irrespective of wireless link utilisation. Using data from a real WISP network, diurnal traffic patterns show that WISP networks could benefit from energy-proportional design, without having to sacrifice performance. To encourage the development of high-performance, energy-proportional WISP backhaul networks, ElasticWISP, an optimisation architecture that reduces network-wide backhaul energy consumption while satisfying the user-demand for traffic, is introduced. ElasticWISP dynamically controls the configuration of backhaul radios based on bandwidth demands and the network-wide energy consumption of these radios. Through simulations driven by real WISP topology and data traffic, results show that ElasticWISP can offer energy savings of approximately 65% when WISP operators follow the proposed backhaul design methodology. Finally, a lightweight Multiprotocol Label Switching (MPLS)-based traffic engineering scheme, based on Segment Routing, is proposed. The implementation, named Segment Routing over MPLS (SR-MPLS), keeps traffic engineering path-state within each packet, meaning per-flow state is only held at SR-MPLS ingress routers. The lightweight approach of SR-MPLS also eliminates the otherwise necessary network-wide label flooding of traditional Segment Routing, making it ideal for bandwidth-sensitive wireless backhaul networks. Evaluation of SR-MPLS shows that it can perform as well as – and sometimes better than – competitor schemes.</p>

ElasticWISP: Energy-Proportional WISP Backhaul Networks

<p>The provision of rural broadband infrastructure is a challenge for network operators across the globe, irrespective of their size. Wireless Internet Service Providers (WISPs) have shown that the small-scale deployment of wireless broadband infrastructure is a viable alternative to relying on cellular network providers for remote coverage. However, WISPs must often resort to using off-grid renewable energy sources such as solar energy for powering network sites, often resulting in undesirable, low-performance backhaul radios being used between sites out of concern for excessive energy consumption. The challenges of managing performant wireless backhaul networks in respect to energy constraints at remote, off-grid sites informs the need for energy-proportional design. Backhaul radios typically used by WISPs are not energy-proportional, meaning they use a consistent amount of energy, irrespective of wireless link utilisation. Using data from a real WISP network, diurnal traffic patterns show that WISP networks could benefit from energy-proportional design, without having to sacrifice performance. To encourage the development of high-performance, energy-proportional WISP backhaul networks, ElasticWISP, an optimisation architecture that reduces network-wide backhaul energy consumption while satisfying the user-demand for traffic, is introduced. ElasticWISP dynamically controls the configuration of backhaul radios based on bandwidth demands and the network-wide energy consumption of these radios. Through simulations driven by real WISP topology and data traffic, results show that ElasticWISP can offer energy savings of approximately 65% when WISP operators follow the proposed backhaul design methodology. Finally, a lightweight Multiprotocol Label Switching (MPLS)-based traffic engineering scheme, based on Segment Routing, is proposed. The implementation, named Segment Routing over MPLS (SR-MPLS), keeps traffic engineering path-state within each packet, meaning per-flow state is only held at SR-MPLS ingress routers. The lightweight approach of SR-MPLS also eliminates the otherwise necessary network-wide label flooding of traditional Segment Routing, making it ideal for bandwidth-sensitive wireless backhaul networks. Evaluation of SR-MPLS shows that it can perform as well as – and sometimes better than – competitor schemes.</p>

Energy Optimization of a Laser-Powered Hovering-UAV Relay in Optical Wireless Backhaul

<div>Due to their flexibility and low cost deployment, unmanned aerial vehicles (UAV) will most likely act as base stations and backhaul relays in the next generation of wireless communication systems. However, these UAVs---in the untethered mode---can only operate for a finite time due to limited energy they carry in their batteries. In free-space optical communications, one solution is to transport both the data and the energy from the source to the UAV through the laser beam---a concept known as <i>simultaneous lightwave information and power transfer</i> (SLIPT). In this study, we have analyzed the SLIPT scheme for laser-powered decode-and-forward UAV relays in an optical wireless backhaul. The major goal of this study is to optimally allocate the received beam energy between the decoding circuit, the transmitting circuit and the rotor block of the relay in order to maximize a quality-of-service metric such as maximum achievable rate, outage or error probabilities. As expected, we note that the optimal power allocation depends heavily on the source-relay and relay-destination channel conditions. In the final part of this study, we have maximized the operational time of the UAV relay given that the maximum achievable rate stays above a certain threshold in order to meet a minimum quality-of-service requirement.</div>

Energy Optimization of a Laser-Powered Hovering-UAV Relay in Optical Wireless Backhaul

<div>Due to their flexibility and low cost deployment, unmanned aerial vehicles (UAV) will most likely act as base stations and backhaul relays in the next generation of wireless communication systems. However, these UAVs---in the untethered mode---can only operate for a finite time due to limited energy they carry in their batteries. In free-space optical communications, one solution is to transport both the data and the energy from the source to the UAV through the laser beam---a concept known as <i>simultaneous lightwave information and power transfer</i> (SLIPT). In this study, we have analyzed the SLIPT scheme for laser-powered decode-and-forward UAV relays in an optical wireless backhaul. The major goal of this study is to optimally allocate the received beam energy between the decoding circuit, the transmitting circuit and the rotor block of the relay in order to maximize a quality-of-service metric such as maximum achievable rate, outage or error probabilities. As expected, we note that the optimal power allocation depends heavily on the source-relay and relay-destination channel conditions. In the final part of this study, we have maximized the operational time of the UAV relay given that the maximum achievable rate stays above a certain threshold in order to meet a minimum quality-of-service requirement.</div>

Wireless Terrestrial Backhaul for 6G Remote Access: Challenges and Low Power Solutions

Despite developments in communication systems over the last few decades, a digital divide exists in the unconnected part of the world. The latter is characterized by large distances to internet access points, underdeveloped infrastructure, sparse populations, and low incomes. This concern of digital divide is raised in the sixth generation’s (6G) initial vision as an extremely important topic. However, it is important to understand affiliated challenges and potential solutions to achieve this vision. Motivated by the recent backhaul link forecasts that expect a dominance of the microwave technology within the backhauling market, this paper studies the potential of a low-power terrestrial microwave backhaul from the sufficient-data-rate and solar powering perspective. Competing technologies (e.g., fiber) may not be energy efficient and commercially viable for global connectivity. Since rural and remote areas may not have grid power, we look at the viability of alternative sustainable sources, in particular solar power, to power the wireless backhaul in 6G. In addition, we also explore services for the operators and users to use the system efficiently. Since the access points are connected to backhaul, we also compare the two prominent solutions based on low-power small-radius cells and a mega-cell that covers a large area and show insights on the power autonomy of the systems. In the end, we propose directions for research and deployment for an inclusive connectivity as a part of future 6G networks.

Accurate Optimization Technique for Phase-Gradient Metasurfaces used in Compact Near-Field Meta-Steering Systems

Near-field Meta-Steering (NFMS) is a constantly evolving and progressively emerging novel antenna beam-steering technology that involves an elegant assembly of a base antenna and a pair of phase-gradient metasurfaces (PGMs) placed in the near-field region of the antenna aperture. The upper PGM in a Near-Field Meta-Steering system receives an oblique incidence from the lower PGM at all times, a fact that is ignored in the traditional design process of upper metasurfaces. This work proposes an accurate optimization method for metasurfaces in NFMS systems to reduce signal leakage by suppressing the grating lobes and side lobes that are innate artifacts of beam-steering. We detail the design and optimization approach for both upper and lower metasurface. Compared to the conventionally optimized compact 2D steering system, the proposed system exhibits higher directivity and lower sidelobe and grating lobe levels within the entire scanning range. The broadside directivity is 1.4 dB higher, and the sidelobe level is 4dB lower in comparison. The beam-steering patterns for the proposed 2D compact design are experimentally validated, and the measured and predicted results are in excellent concurrence. The versatile compatibility of truncated PGMs with a low gain antenna makes it a compelling technology for wireless backhaul mesh networks and future antenna hardware.

Energy Optimization of a Laser-Powered Hovering-UAV Relay in Optical Wireless Backhaul

Due to their flexibility and low cost deployment, unmanned aerial vehicles (UAV) will most likely act as base stations and backhaul relays in the next generation of wireless communication systems. However, these UAVs---in the untethered mode---can only operate for a finite time due to limited energy they carry in their batteries. In free-space optical communications, one solution is to transport both the data and the energy from the source to the UAV through the laser beam---a concept known as simultaneous lightwave information and power transfer (SLIPT). In this study, we have analyzed the SLIPT scheme for laser-powered decode-and-forward UAV relays in an optical wireless backhaul. The major goal of this study is to optimally allocate the received beam energy between the decoding circuit, the transmitting circuit and the rotor block of the relay in order to maximize a quality-of-service metric such as maximum achievable rate, outage or error probabilities. As expected, we note that the optimal power allocation depends heavily on the source-relay and relay-destination channel conditions. In the final part of this study, we have maximized the operational time of the UAV relay given that the maximum achievable rate stays above a certain threshold in order to meet a minimum quality-of-service requirement.