Search results for " Network"

Analysis on channel bonding/aggregation for multi-channel cognitive radio networks

2010

Channel bonding/aggregation techniques, which assemble several channels together as one channel, could be used in cognitive radio networks for the purpose of achieving better bandwidth utilization. In existing work on this topic, channel bonding/aggregation is focused on the cases when primary channels are time slotted or stationary as compared with secondary users' activities. In this paper, we analyze the performance of channel bonding/aggregation strategies when primary channels are not time slotted and the time scale of primary activities is at the same level as the secondary users', given that spectrum handover is not allowed. Continuous time Markov chain models are built in order to a…

5G V2V Communication With Antenna Selection Based on Context Awareness: Signaling and Performance Study

2022

Enhanced vehicle-to-everything (eV2X) communication is one of the key challenges to be addressed by the fifth generation (5G) of cellular mobile communications. In particular, eV2X includes some 5G vehicular applications targeting fully autonomous driving which require ultra-high reliability. Although vehicular communications are by default assumed between single antennas located on the roof of the transmitter and receiver vehicles, prior art has shown that there are other antenna positions more suitable for V2X communication, depending on the specific communication context. Antenna selection can be used in this case to select one specific antenna or a subset of them better suited for a cer…

Virtualization of Remote Devices and Services in Residential Networks

2009

Lately solutions for remote access for residential services have been proposed. However, these solutions require modifications to the service controllers. In addition, remote access adds complexity to the client application. We propose here a solution for decoupling remote access from the client itself with an entity that creates virtual instances of remote services in a local network. Thereby, clients will be able to discover the virtual instance and use it. Moreover, client applications do not need to distinguish between local and remote services hence reducing complexity.

Security in mobile agent systems

2007

Priority Enabled Grant-Free Access With Dynamic Slot Allocation for Heterogeneous mMTC Traffic in 5G NR Networks

2021

Although grant-based mechanisms have been a predominant approach for wireless access for years, the additional latency required for initial handshake message exchange and the extra control overhead for packet transmissions have stimulated the emergence of grant-free (GF) transmission. GF access provides a promising mechanism for carrying low and moderate traffic with small data and fits especially well for massive machine type communications (mMTC) applications. Despite a surge of interest in GF access, how to handle heterogeneous mMTC traffic based on GF mechanisms has not been investigated in depth. In this paper, we propose a priority enabled GF access scheme which performs dynamic slot …

DTMC modeling for performance evaluation of DW-MAC in wireless sensor networks

2016

Synchronized duty cycling (DC) aligns sensor nodes to wake up at the same time in order to reduce idle listening for medium access control (MAC) in wireless sensor networks (WSNs). Demand wakeup MAC (DW-MAC) is a popular synchronous DC MAC protocol which allows nodes to compete and transmit multiple packets in one operational cycle. This multiple packet transmission (MPT) feature makes DW-MAC more energy efficient when comparing with other existing single time competition based protocols such as sensor MAC (S-MAC). In the literature, no analytical model exists to evaluate the performance of DW-MAC. In this paper, we develop two associated discrete time Markov chain (DTMC) models and incorpo…

A simulation study of load balancing algorithms in cellular packet networks

2001

This paper provides a comparative performance evaluation of various load balancing schemes in cellular packet networks. With respect to traditional schemes, that measure each cell load in terms of number of admitted calls, our schemes use supplementary packet level information, expressed in terms of effective resource consumption of each individual call when retransmission mechanisms are employed. The simulation model adopted is based on a toroidal cellular network topology, to avoid border effects affecting the numerical results.

A Self-Powered Long-range Wireless IoT Device based on LoRaWAN

2020

In this article, we propose a self-powered long-range wireless Internet-of-Things (IoT) device based on Long Range Wide Area Network (LoRaWAN) with various sensing capabilities. The nodes are designed based on ambient energy harvesting in such a way that these are self-sustainable throughout the components’ lifespan. Also, these nodes can be deployed on a large scale and are maintenance-free. In addition, these nodes can be deployed in remote places where the accessibility is limited, and maintenance is difficult. The wireless sensor nodes can be deployed both in indoor and outdoor environments with sufficient light levels for the solar panel, such as indoor lights in the indoor environment…

Face Processing on Low-Power Devices

2009

The research on embedded vision-based techniques is considered nowadays as one of the most interesting matters of computer vision. In this work we address the scenario in which a real-time face processing system is needed to monitor people walking through some locations. Some face detection (e.g., Viola-Jones face detector) and face recognition (e.g., eigenfaces) approaches have reached a certain level of maturity, so we focused on the development of such techniques on embedded systems taking into account both hardware and software constraints. Our goal is to detect the presence of some known individuals inside some sensitive areas producing a compact description of the observed people. Cap…

FoSBaS: A bi-directional secrecy and collusion resilience key management scheme for BANs

2012

Body Area Network (BAN) consists of various types of small physiological sensors, transmission modules and low computational components and can thus form an E-health solution for continuous all-day and any-place health monitoring. To protect confidentiality of collected data, a shared group key is usually deployed in a BAN, and consequently a secure communication group is generated. In this paper, we propose a bi-directional security and collusion resilience key management scheme for BAN, referred to as FoSBaS. Detailed analysis shows that the scheme can provide both forward security and backward security and resist against collusion attacks. Furthermore, the FoSBaS is implemented on a Sun …