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In the horizontal atmospheric turbulent channel of optical wireless communication (OWC), anisotropy has been proved to be one of essential properties. This paper investigates the long term beam spread and the beam wander of Gaussian beam based on the generalized anisotropic non-Kolmogorov power spectrum, where all the influence of the anisotropy of turbulence, the finite turbulence inner and outer...
Wireless energy transfer causes heating in the surrounding tissue due to radiation. We address this issue in a joint wireless information and energy transfer setting. We consider the optimal joint wireless information and energy transfer subject to a peak temperature constraint at the receiver side in a deadline constrained frequency selective additive white Gaussian noise channel. We model the temperature...
We consider the operation of an energy harvesting wireless device (sensor node) powered by a rechargeable battery, taking non-idealities into account. In particular, we consider sudden decrease and increase of the battery level (leakage and charge recovery consequently) due to the inner diffusion processes in the battery. These processes are affecting the stability of the device operation. In particular,...
In this paper, we investigate a multi-node multi-antenna wireless-powered sensor networks (WPSN) comprised of one power beacon and multiple sensor nodes. The proposed beam-splitting technique enables a power beacon to split microwave energy beams towards multiple nodes for simultaneous charging. We propose an optimal joint beam-splitting and energy neutral control algorithm for perpetual operation...
Mobile Edge Computing (MEC) plays a key role in the 5G roadmap, as a way to bring information technology (IT) services closer to the mobile users by empowering radio access points with additional functionalities, like caching or computation offloading capabilities. At the physical layer, some of the key technologies enabling very low latency mobile services are dense deployment of radio access points,...
In the world of Internet of Things (IoT), it is desired that every IoT device is able to communicate with the network all the time. Among various technologies to enable network connectivity, Long Term Evolution (LTE) is by far the most ubiquitous technology to provide coverage for IoT devices. The IoT devices are inherently resource constraint and efficient communication is one of the primary requirements...
To increase the communication range of multi-hop cognitive radio networks (CRNs) while avoiding the implied loss in throughput, use of incremental relaying has been suggested. In this paper, we discuss an incremental relaying (IR) protocol for cooperative multi-hop CRNs (CMHCRNs). A CMHCRN with multiple decode-and-forward relays in each hop is considered. In each hop, the relays whose received signal-to-noise-ratio...
The provision of both wireless and wired services in the optical access domain will be an important function for future passive optical networks (PON). With the emergence of 5th generation (5G) mobile communications, a move toward a dense deployment of small cell antenna sites, in conjunction with a cloud radio access network (C-RAN) architecture, is foreseen. This type of network architecture greatly...
One of the main 5G issues is to enable flexible multiple access to fragmented spectrum with relaxed synchronicity. Unfortunately, the classical OFDM cannot fulfill this criterion, since a tight synchronization is essential to ensure free-distortion multiple access. Windowing is one of the most popular approaches that have been proposed to overcome this problem. In this paper, we investigate the enhancement...
Non-orthogonal multiple access (NOMA) is a promising technique for the fifth generation mobile communication system due to its high spectral efficiency (SE). Previous works focus on user scheduling or/and power allocation to achieve the maximization of sum rate. However, the energy efficiency (EE) has not been well studied for NOMA systems. In this paper, we aim to optimize user scheduling and power...
The energy efficiency of network hardware has become a topic of considerable interest in recent years, motivated by the explosive growth of information and communication technology (ICT), and the ever increasing energy costs as well as the need to reduce Greenhouse Gas (GHG) emissions globally. One approach to saving energy in routers is to use dynamic adaptation, and this paper describes the development...
Typically Ternary Content Addressable Memories (TCAMs) are used for simple lookups inside forwarding or routing information bases in routers or switches. We propose a new application of TCAM as the element of switching fabric control module inside a switching node, which is able to directly determine the set of established connections that block an arriving connection. We propose an algorithm called...
Next generation use-cases of wireless IP networks, including especially the Massive Machine Type Communications and IoT applications for the distribution of sensory and similar data will require the capability to handle large number of connections while maintaining a low-power footprint in order to function efficiently during long-term deployments. The reduction of the packetisation overhead resulting...
In this paper, we focus on the statistical characteristics of 3D channel propagation in indoor scenario with dense users. Measurements were performed at 3.5 and 6 GHz with 100 MHz by using an uniform cross-polarized rectangular transmitter (Tx) with 32 antennas and a cylindric cross-polarized receiver with 56 antennas. Placing the Tx at two different positions, against the wall which radiates signals...
The concept of Ultra Dense Networks (UDNs) is often seen as a key enabler of the next generation mobile networks. However, existing analysis of UDNs, including Stochastic Geometry, has not been able to fully determine the potential gains and limits of densification. In this paper we study performance of UDNs in downlink and provide new insights on the impact of antenna height on the network performance...
New idle-time based random access scheme, Adaptive p-persistent, is proposed for super dense wireless networks. By utilizing idle-time information, Adaptive p-persistent scheme is designed to be not only scalable to support massive number of devices but also adaptive to dynamically changing traffic load; each device updates its persistent level p every time it receives or overhears a new packet based...
Message dissemination is considered as a challenging task in Vehicular Ad-hoc network (VANET). In particular, safety messages, such as, road accident warning, traffic congestion warning, etc., are the most critical messages type that need to be efficiently transmitted in a wireless and mobile network where the topology changes dynamically. Many protocols have been proposed for the sake of disseminating...
The broadcast nature of wireless communication make it intrinsically vulnerable to jamming and eavesdropping attacks. Spread-spectrum techniques spread narrowband signals over a wide bandwidth, and provide good resistance to noise and jamming attacks. However, spread-spectrum signals can still be intercepted if their used spreading codes are known. To tackle this issue, this paper proposes a lightweight...
In this paper, we consider a cognitive indoor visible light communications (VLC) system, comprised of multiple access points serving primary and secondary users through the orthogonal frequency division multiple access method. A cognitive lighting cell is divided into two non-overlapping regions that distinguish the primary and secondary users based on the region they are located in. Under the assumption...
This paper proposes a multi-channel medium access control (MAC) protocol for hybrid VLC/Wifi networks. The proposed MAC protocol is based on an integration of two standards, IEEE 802.15.7 VLC and IEEE 802.11 Wifi CSMA/CA(s) (Carrier Sense Multiple Access/Collision Avoidance). We newly add on top of current MAC protocols a sub-layer that runs dynamic channel selection by taking intelligent control...
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