Academic Background

2000 - 2004 : Bachelor of Engineering (B.E.) in Electronics and Communication Engineering, Institute of Engineering, Pulchowk Campus, Nepal

2006 - 2008 : Master of Engineering (M.E.), Tokyo Institute of Technology, Tokyo, Japan

2009 - till date : Ph.D student, Simula Research Laboratory and University of Oslo, Norway

Professional Experience

2004 - 2006 : Lecturer, Kantipur Engineering College, Nepal

2007 - 2008 : Research Assistant, Tokyo Institute of Technology, Japan

2007 - 2009: Teaching Assistant, Tokyo Institute of Technology, Japan

Research Interest

• Spectrum Sensing and Scheduling
  
• Cross Layer Design in Cognitive Radio Networks and Smart Grid Communications
  
• Game Theory
• Demand Response Management in Smart Grid
  

Cross Layer Design in Cognitive Radio Networks

While CR technology opens the doors to a huge world of opportunities for next generation networks, it also poses numerous challenges to be addressed. Apart from the requirement of reliable and accurate methods for spectrum sensing and spectrum mobility, the requirements in terms of reliability and accuracy required for routing the gathered information about spectrum sensing in the network, maintaining Quality of service (QoS) for user communication applications are also very high. After all, the responsibility of ensuring that the PUs do not get interfered by SU activities is totally on SUs.

Most of the ongoing work on CRNs focusses on the anaysis of detection performance and on optimization of different parameters at different layers. However, the connection from one layer to another is of great  importance too. Therefore, the need of analyzing the performance from cross layer point of view is not of less significance. Unlike cross layer issues in traditional wireless networks, the cross layer design in CRNs poses tremendous number of challenges due to broad range of available spectrum as well as diverse QoS requirements of applications.

Cross layer design addresses the problems of wireless network performance whose cause can be tracked back to the assumptions made for designing the architecture of the network and its protocol stacks. Cross layer design makes it possible even for non-adjacent layers to communicate with each other through additional entities introduced into the system. Another very important aspect of cross layer design for cognitive radio networks is the joint consideration of parameters at different layers (adjacent or non-adjacent) for resource optimization which is not possible using traditional layered approach. On the other hand, the cost of cross layer design can be the overhead on the system due to cross-layer communication. We are also interested to investigate this trade-off in cognitive radio networks. This research work is a part of Wireless Resilient Networks project under the supervision of Prof. Stein Gjessing and Asso. Prof. Dr. Yan Zhang.

My PhD research comprises of the following three important aspects of wireless communications:

1. My current research aims to propose new ideas and algorithms to improve network efficiency and reliability in cognitive radio networks. I model the behavior of primary and secondary users for the coexistence of cognitive radio networks with the primary networks and study the conflict and cooperation among them employing economic approaches such as game theoretical models, price theory, market theory etc.
2. The second aspect of my research is on applying the cognitive radio technology for Smart Grid.  Smart grid is envisioned to be the next generation of power grid, which will be integrated with feedback communication to improve agility, reliability and efficiency of the grid. We propose cognitive radio enabled smart grid communication which supports and improves two fundamental requirements of smart grid: reliability and timeliness of the information flow between the power supply unit and the power consumers.
3. The third aspect of my research focuses on applying game theoretical framework to develop new approaches and distributed algorithms for demand response management in smart grid.

Publications

Book Chapters

, "Economic Approaches in Cognitive Radio Networks," in Cognitive Radio Mobile Ad Hoc Networks, edited by F. Richard Yu, Springer, USA, 2011.

1.      S. Maharjan, Y. Zhang, and S. Gjessing, "Economic Approaches in Cognitive Radio Networks: A Survey", Special Issue, CogCom, Springer Wireless Personal Communications (WPC), Volume 57, Issue 1, pp. 33-51, 2011 (published online in May 2010).

1. R. Ruilong, S. Maharjan, X. Cao, J. Chen, Y. Zhang and S. Gjessing, "Sensing-delay Tradeoff for Communication in Cognitive Radio Enabled Smart Grid", IEEE SmartGridComm 2011.
   
2. S. Maharjan, Y. Zhang, C. Yuen and S. Gjessing, "Distributed Spectrum Sensing in Cognitive Radio Networks with Fairness Consideration: Efficiency of Correlated Equilibrium", IEEE Mobile Ad-hoc and Sensor Systems (MASS), 2011.
3. S. Maharjan, C. Yuen, Y. Chew, Y. Zhang and S. Gjessing, "Distributed Spectrum Sensing for Cognitive Radio Networks with Heterogeneous Traffic", CogART 2010 (Invited paper)
4. S. Maharjan, J. Xiang, Y. Zhang and S. Gjessing, "Delay Reduction for Real Time Services in IEEE 802.22 Wireless Regional Area Network", 21st Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), September 2010, Istanbul Turkey.
5. S. Maharjan, Y. Zhang and S. Gjessing, "Economic Approaches in Cognitive Radio Networks: A Survey", Special Issue, CogCOM, Springer Wireless Personal Communications (WPC), 2010
   
6.  S. Maharjan, M. Kim and J. Takada, "Practical Detection Issues of Spectrum Sensing for Cognitive Radio System", IEICE Society Conference, 2009 (2009-1), Kyoto University, Kyoto, Japan
7.  S. Maharjan, M. Kim, K. Po and J. Takada, "Influence of Quantization on Detection Performance of Cognitive Radio Receiver”, IEICE Society Conference, 2008 (2008-9), Meiji University, Kawasaki, Japan
8. M. Kim, R. Ryo, K. Po, S. Maharjan and J. Takada, “Development of Spectrum Sensing Evaluation System”, IEICE Technical Report, SR-2008-(2008-7), NICT, Koganei, Tokyo, Japan.
9. S. Maharjan, K. Po and J. Takada, "Experimental Study of Energy Detector Prototype for Cognitive Radio System", IEICE Technical Report, SR-2007-52(2007-11), Hiroshima International University, Hiroshima, Japan
10.  S. Maharjan, K. Po and J. Takada, "Energy Detector Prototype for Cognitive Radio System", pp. 29-33, IEICE Technical Report, SR-2007-25(2007-7), Yokosuka Research Park, Tokyo, Japan
11.  "Promoting Sustainable Development in Education through UNESCO Development Project in Mongolia", Field visit to Mongolia and Contribution as a Student Member in the Preparation of the Analysis Paper of the Project, pp. 1-74, May 2007, Tokyo Institute of Technology,  http://www.unescobeijing.org/detail.do?type=publication&pubDocumentId=1200035068006
12. S. Maharjan, “If you were the head of state of your country what role would you make young people play in advancing ICT as a means for economic and social development in your country”, pp. 327-328, ITU Essay Book, ITU Telecom World 2003, Oct. 12-18, 2003, Geneva, Switchzerland, (Representative from Nepal)