Eion (Canada)

In this paper, we propose a novel UAV to UAV communication approach that is based on the concept of Software Defined Networking (SDN). The proposed approach uses a controller as a central source of information to assign routes that maximize throughput, distribute traffic evenly, reduce network delay and utilize all network elements. Simulation results of the proposed methodology were compared to the performance of two common ad hoc routing protocols, namely AODV and OLSR. Performance analysis shows that the proposed methodology improves throughput by over 300%. Simulation results also show a reduction in network delay for delay sensitive packets by nearly 25% and a 26 times increase in packet delivery ratio for packets with higher priority.

In the pursuit of ever increasing demand of higher data rates, modern wireless communication systems are resorting to tighter frequency reuse patterns thereby leading to interference-limited systems. Recently proposed interference-aware receiver [1] is a low complexity and efficient receiver design for interference mitigation in cellular systems. However this advanced receiver necessitates the channel knowledge of both the desired and interfering signals which may not be available in a practical system. In this paper, we investigate the performance of interference-aware receiver under imperfect channel state information (CSI). We consider uncorrelated Rayleigh flat fading channels and model the estimation error as independent complex Gaussian random variables. We derive upper bound on the pair wise error probability (PEP) and show that the interference-aware receiver is characterized by full diversity in the presence of channel estimation errors. We compare the performance of interference-aware receiver with that of MMSE receiver and show that the degradation in the performance of MMSE receiver is much more pronounced than that of interference-aware receiver under imperfect CSI.

This paper addresses the Quality of Service (QoS) degradation problem of wireless relay node failures in multihop Worldwide interoperable Microwave Access (WiMAX) and Long Term Evolution (LTE) networks. In general, node protection in a communication network increases the reliability of the traffic flow from source to destination. For wireless networks, implementing the traditional 1+1 protection scheme increases the capital cost, as resources cannot be fully utilized. On the other hand, the design and implementation of the 1:N protection scheme in wireless networks for greater value of N (> 2) is very difficult, due to wireless network coverage and the physical layer design. To overcome the above drawbacks, a technique based on network coding is proposed for node protection in multihop wireless networks. In multihop wireless networks, few research efforts are concentrated on node protection schemes using network coding. Moreover, to best of our knowledge, no reports have been published on measuring the QoS performance for node protection in 4G wireless networks using network coding. In this paper, we first describe the node protection scheme using XOR network coding for multihop 4G wireless networks. Then, we measure the QoS performance, such as packet delivery ratio (PDR), latency and jitter, for different scenarios. The scenarios include a failure of a single relay node and failures of two relay nodes with and without our protection scheme and user's mobility. The simulation results show that the QoS performance with protection against a single relay node failure and failures of two relay nodes are very close to that of no failure scenario, while the network reliability increases due to the protection mechanism. Also, we report a decoding problem in multihop wireless networks using XOR network coding.

WiMAX technology provides a Quality of Service (QoS) system that allows system operators to configure a network to provide maximum performance compared to conventional Best Effort (BE) systems. In this paper, we address the increase in number of data rich mobile devices and the performance issues associated with Video On Demand (VOD) multimedia traffic over a WiMAX network. We present the results of application testing using WiMAX protocol where the main focus is to show how utilizing a QoS system can benefit streaming real time multimedia. The results show how WiMAX technology is beneficial to multimedia applications.

A Smart grid is characterized by two-way flows of power in electrical networks and information in communication networks [1]. The characteristics of communications in a smart grid vary for different applications that exist between control centers and power generating stations, distribution stations and consumer areas. For effective communications, proper communication network design and the selection of technology is essential. In this paper, we analyze the communication requirements of smart grids in electrical power distribution areas and in consumer places. As the communication in a Distribution Area Network (DAN) integrate the AMIs payload from the consumer area, it is necessary to analyze the data flow from the consumer area to control centers through a DAN. Few communication technologies are available to implement the DAN. Among that, WiMAX and LTE are more suitable than other technologies, as they satisfy the communication requirements and the cost. Little research has been conducted on analyzing and simulating the DAN by considering various applications that exist in a DAN. In this paper, we measure the smart metering capacity and the Quality of Service (QoS) performance (packet loss and latency) of DAN using WiMAX technology. From the obtained results, we also suggest that the 4G technologies are (WiMAX and LTE) more suitable candidate than existing cellular and wire line technologies for implementing the DAN in smart grids.

Device-to-device (D2D) communication as an underlaying cellular network empowers user-driven rich multimedia applications and also has proven to be network efficient offloading eNodeB traffic. However, D2D transmitters may cause significant amount of interference to the primary cellular network when radio resources are shared between them. During the downlink (DL) phase, primary cell UE (user equipment) may suffer from interference by the D2D transmitter. On the other hand, the immobile eNodeB is the victim of interference by the D2D transmitter during the uplink (UL) phase when radio resources are allocated randomly. Such interference can be avoided otherwise diminish if radio resource allocated intelligently with the coordination from the eNodeB. In this paper, we formulate the problem of radio resource allocation to the D2D communications as a mixed integer nonlinear programming (MINLP). Such an optimization problem is notoriously hard to solve within fast scheduling period of the Long Term Evolution (LTE) network. We therefore propose an alternative greedy heuristic algorithm that can lessen interference to the primary cellular network utilizing channel gain information. We also perform extensive simulation to prove the efficacy of the proposed algorithm.

The optimal relay selection problem in multiuser cooperative wireless networks is considered in this paper. A general discrete time model for such networks is introduced which takes into account the dynamic variations of the channel state as well as stochastic arrival of data packets into the system. The model consists of a set of mobile users, one destination node and R relay nodes which may be either mobile or fixed. The system uses the benefit of cooperative diversity by relaying in decode and forward or amplify and forward mode. We assume that each user either transmits its packets directly to the destination or selects a relay node to cooperatively transmit its packets. It is not however trivial whether a user at each time slot has to cooperate with any relay node or not and if so, which relay node should be selected for cooperation. We will propose a throughput optimal relay selection policy that can stabilize the system for all the arrival rate vectors strictly inside the stability region. Then, we show that the optimal policy is equivalent to finding the maximum weighted matching in a weighted bipartite graph at each time slot. We also use simulations to compare the performance of the throughput optimal relay selection strategy with an instantaneous throughput optimal policy as well as a non-cooperative policy in terms of average queue occupancy (or equivalently, queueing delay).

Weather attenuations can have a distorting effect on signal fidelity above 10 GHz that lead to excessive digital transmission error. This loss of signal is commonly referred to as signal attenuation. Signal attenuation impacts QoS in wireless and satellite networks. An intelligent decision support system is therefore necessary for service providers by accurately calculating rain, gaseous, cloud, fog, and scintillation attenuations using predicted signal-weather correlated database in collaboration with ITU-R propagation models combined with gateway, and ground terminal characteristics. The effect becomes a key feature in adjusting and improving satellite signal power, modulation and coding schemes, monitored and controlled altogether by a powerful and efficient intelligent-based attenuation countermeasure system. A three dimensional relationship is proposed among these attenuations with respect to propagation angle and rainfall rate (Harb et al., 2007). The result pilots an enhanced back propagation-learning algorithm that is used to iteratively tune the intelligent controller based on fuzzy logic technique with returned SNR values for activating the weighted Modulation/Codepoint to its optimal values, depending on actual or predicted weather conditions, configuration settings and tolerance/safety margins for SLA commitment.