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Rahman M.M.,University of Quebec at Montreal | Despins C.,Prompt Inc | Affes S.,University of Quebec at Montreal
Proceedings - 2014 3rd International Conference on Eco-Friendly Computing and Communication Systems, ICECCS 2014 | Year: 2014

Wireless access virtualization is considered to be a major enabling concept of future 5G networks. It fosters network innovation, rapid time to market for emerging networking concepts and enables cohabitation of different virtual networks with customized network protocols on the same physical infrastructure. It can also alleviate the ossification problem of radio spectrum that has been a major concern for telecommunication operators. Virtualization is also a key enabler for green communications as it not only reduces energy consumption by ensuring efficient use of hardware resources through resource sharing but also facilitates use of renewable energy sources for the communications infrastructure. This paper presents two different types of frameworks to classify wireless network virtualization design alternatives. The benefits of virtual wireless networks are very often expected from a cost perspective. Yet provisioning of stringent quality of service (QoS) requirements calls for a thorough analysis especially from PHY & MAC layers perspectives. A method for selecting the most efficient network architecture has been proposed that takes into account both network operators' (and/or service providers') cost and QoS constraints. The analytical model considers both the capital expenditure (CAPEX) and operational expenditure (OPEX) for cost analysis, while the achievable data rate in different virtual frameworks has been considered for QoS modelling. © 2014 IEEE. Source

Rahman M.M.,University of Quebec at Montreal | Despins C.,Prompt Inc | Affes S.,University of Quebec at Montreal
1st IEEE Conference on Network Softwarization: Software-Defined Infrastructures for Networks, Clouds, IoT and Services, NETSOFT 2015 | Year: 2015

Virtualization is seen as a killer application of software defined networking (SDN). Virtual radio access network (RAN) is an emerging concept for 5G and beyond 5G networks and it is gaining increased attention from both academia and industry alike. Moreover, due to the current telecommunication trend of increasing network traffic and decreasing revenue, telecom operators all over the world are looking for network function virtualization (NFV) to reduce network deployment and running cost by maximizing resource sharing. In this paper, we classify virtual RAN into three possible PHY-MAC models that leverage SDN for virtualizing the underlying RAN substrate. A novel multi-criteria utility function is also proposed to evaluate the trade-offs between network cost and achievable QoS from PHY-MAC layers perspectives of these virtual RAN models. Analytical results show that a hybrid virtualization model attains the optimal balance between network cost and QoS and hence is the best virtual RAN model. © 2015 IEEE. Source

Jha S.C.,University of British Columbia | Rashid M.M.,University of British Columbia | Bhargava V.K.,University of British Columbia | Despins C.,Prompt Inc
IEEE Wireless Communications | Year: 2011

Since cognitive radio technology can significantly boost spectrum utilization by exploiting radio spectrum unused by licensed users, it is rapidly gaining popularity and inspiring numerous applications. However, many technical issues still need to be addressed for successful deployment of CR networks, especially in the MAC layer. We focus on CR networks that have distributed architecture because they offer ease of deployment, self-organizing capability, and flexibility in design, and are believed to be more practical for future deployments compared to their centralized counterparts. The MAC protocols for distributed CR networks should consider the key features of these networks such as lack of a central unit to coordinate the communication, dynamic topology, requirements to keep interference to primary users minimal, and variation of spectrum availability with time and location. To clarify the relevant research challenges and issues, we provide a detailed study of the critical design issues and an overview of current state-of-the-art MAC protocols proposed for DCRNs. A classification of existing proposals is provided, and their salient features, advantages, and limitations are discussed. We then introduce and study a novel MAC protocol that addresses some of the research issues better than existing solutions. We also highlight important research challenges that could drive future research in this area. © 2011 IEEE. Source

Despins C.,Prompt Inc | Labeau F.,McGill University | Le Ngoc T.,SRTelecom Inc. | Labelle R.,McGill University | And 9 more authors.
IEEE Communications Magazine | Year: 2011

Green communication systems and, in broader terms, green information and communications technologies have the potential to significantly reduce greenhouse gas emissions worldwide. This article provides an overview of two issues related to achieving the full carbon abatement potential of ICT. First, green communications research challenges are discussed, notably as they pertain to networking issues. Various initiatives regarding green ICT testbeds are presented in the same realm in order to validate the ¿green performance¿ and functionality of such greener cyber-infrastructure. Second, this article offers a description of ongoing international efforts to standardize methodologies that accurately quantify the carbon abatement potential of ICTs, an essential tool to ensure the economic viability of green ICT in the low carbon economy and carbon credit marketplace of the 21st century. © 2011 IEEE. Source

Punchihewa A.,University of British Columbia | Bhargava V.K.,University of British Columbia | Despins C.,Prompt Inc
IEEE Transactions on Wireless Communications | Year: 2011

This paper presents a lower-bound on the ergodic sum capacity of single-input single-output (SISO) opportunistic spectrum sharing multiple access channel (MAC) in Rayleigh fading channels with imperfect channel estimates. Unlike the previous studies, this paper considerers the channel estimation errors for both sets of SISO channels between the secondary user (SU) transmitters and the SU receiver and between the SU transmitters and the primary user receivers. By considering these channel estimation errors, an optimal power allocation policy for each SU transmitter is derived to achieve a lower-bound of the ergodic sum capacity of opportunistic spectrum sharing MAC, subject to a set of SUs transmit power constraints and a set of interference power constraints at each PU receiver. Furthermore, convex optimization techniques are exploited to derive an efficient algorithm to obtain the optimal power allocation for each SU transmitter. Numerical results are presented to illustrate the influences of the channel estimation errors on the ergodic sum capacity. © 2011 IEEE. Source

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