I'm Rajarajan Sivaraj, a PhD candidate in the Department of Computer Science at the University of California, Davis, USA, supervised by Prof. Prasant Mohapatra. I work on problems concerning radio resource management and Quality-of-Service provisioning in next-generation OFDMA cellular networks, such as 3GPP LTE-Advanced, from theory, simulations and systems perspectives. Particularly, I focus on 4G+/5G technologies on both the radio access network (RAN) as well as the mobile user modem. I have published on the design of cross-layer optimization algorithms for advanced RAN architecture, LTE systems prototyping and deployment, networking and link simulations, numerical analysis and performance evaluation. I've had a citation count of 210 (till Aug 1) over my 6 years of research career and I was awarded an Honorable Mention in recognition of my outstanding graduate research by the department of CS at UC Davis.
I'm joining AT&T labs Research, San Ramon, CA, as a Senior Member of Technical Staff in Jan 2017.
My areas of expertise include:
Telecommunications: 3GPP LTE-Advanced, Unlicensed LTE, License-Assisted Access, LTE-WiFi Link Aggregation, Carrier Aggregation, eMBMS and Single Frequency Networks, eICIC, Coordinated Multi-point Transmission and beamforming (CoMP)
Wireless: MIMO-OFDM beamforming, Multi-user MIMO, MIMO Channel estimation and de-precoding, Open-loop and closed-loop MIMO Receiver design, Multi-antenna communication
Machine Learning: Convex Optimization, Sub-modular Optimization, Cooperative graph-Cuts
System Prototyping/characterization: LTE real L2/L3 eNB, WiMAX L2 base station (pico-chip testbed), Intel Software-defined Radio for LTE MODEM, Qualcomm QXDM/QCAT, LTE-unlicensed Femto-cell Access Point in TV White Space, Wireshark
Simulations/Coding: NS3 LTE/EPC Network Simulator, LTE Toolbox in Matlab, NS2 (Tcl/C++), Poco C++, C/C++/Java, Matlab, Awk scripts
Relevant Graduate Courses: Network Theory, Algorithm design and optimization, Computer Networks, Special Topics on Next-Generation LTE and WiMAX networks, Performance Evaluation, Networking Architecture and Resource Management, Operation System Models, Computer Architecture, Computer Security, Network Planning, Design and Optimization, Finite Model Theory.
During PhD, I have had internship experiences in some of the most-competitive top-notch research labs in the industry (relevant to my Ph.D thesis), which include:
Microsoft Research (Cambridge, UK) during Spring 2016 where I was working with Bozidar Radunovic in the Networking and Systems research group on characterizing VoLTE traffic in LTE unlicensed TV White Space band for achieving low latency in 5G networks.
Intel Labs (Santa Clara, CA) during Summer 2015 in the Micro-architecture design research labs on the efficient and flexible design of MIMO-MMSE receivers for LTE MODEMs and their implementation/prototyping on a software-defined radio.
NEC Laboratories (Princeton, NJ) during Summer 2014 where I was working with Karthik Sundaresan and Mustafa Arslan in the Mobile Communications and Networking Research group on the design of efficient algorithms for video broadcasting over LTE single frequency networks,
AT&T Research (Florham Park, NJ) during Summer 2013 where I was working with Ioannis Broustis and Vaneet Aggarwal (currently, with Purdue University) in the Networking and Services Quality Research group on the design of efficient eICIC algorithms to mitigate macro-small cell interference in LTE-Advanced systems supporting Carrier Aggregation,
Broadcom (Sunnyvale, CA) during Summer 2012 where I was working with Kamlesh Rath (currently, with Quantenna communications) in the LTE systems engineering team on the prototyping of low-latency schedulers for uplink on both the MODEM side as well as the radio access network on real TD-LTE L2 eNB with emulated PHY.
During Fall 2012, I visited the University of New South Wales, Networks Research group, upon invitation by Prof. Sanjay Jha to study problems concerning multi-cell resource allocation in Coordinated multi-point systems, which we subsequently extended for Unlicensed LTE features in 5G, such as License-Assisted Access (LAA) and LTE-WiFi Link Aggregation (LWA). Prior to my PhD, I was working as a researcher at Embedded Systems Innovation Labs, Tata Consultancy Services, Bangalore, India for 8 months during 2010. I was interning with Prof. Abderrahim Benslimane at University of Avignon, France, from Nov-Dec 2009.
I have achieved the following honors in my PhD:
I was awarded the "Honorable Mention in Recognition of Outstanding Graduate Research" by the Graduate Group of Computer Science, UC Davis, for the year 2015-16 with a cash prize of $500 USD
I won the Spring Quarter 2015 GGCS Fellowship of $10,500 USD from the Graduate Group of Computer Science, UC Davis.
I was nominated for AT&T's virtual university research initiative (VURI) for a PhD fellowship of $30,000 USD for 2013-14.
I have had a publication citation count of 210 till date, spanning over my PhD career from 2011. My conference publications in PhD have been in highly-selective venues with less than 25% acceptance rates. I have won NSF, IEEE/IFIP and UC Davis-sponsored travel grant awards in all my conference participations.
Rajarajan Sivaraj , Prasant Mohapatra, "Future Radio Access, Wi-Fi LTE, LTE-Advanced: the path to 5G", Book Chapter, Fiber-Wireless Convergence in Next-Generation Communication Networks, Springer Optical Network Series , ISBN 978-3-319-42822-2, 2017.
Rajarajan Sivaraj , Vaneet Aggarwal, Zizhan Zheng, Sanjay Jha, Prasant Mohapatra, "Fi-G: Aggregating cellular carriers from LTE-licensed and WiFi-unlicensed bands", Submitted, 2017
Rajarajan Sivaraj , Ioannis Broustis, N.K. Shankaranarayanan, Rittwik Jana, Vaneet Aggarwal, Prasant Mohapatra, "A QoS-enabled Holistic Optimization Framework for LTE-Advanced HetNets" , IEEE INFOCOM, San Francisco, Apr 2016 [PPTX] [Acceptance Rate: 18.25%, Citation: 1]
Rajarajan Sivaraj , Ioannis Broustis, N. K. Shankaranarayanan, Vaneet Aggarwal, Prasant Mohapatra, "Mitigating Macro-cell Outage in LTE-Advanced Deployments", in Proc. IEEE INFOCOM, Hong Kong, Apr 2015[PPTX] [Acceptance Rate: 19%]
Amit Pande, Vishal Ahuja, Rajarajan Sivaraj , Eilwoo Baik, Prasant Mohapatra, "Video Delivery over 4G Networks : Challenges and Opportunities", IEEE Multimedia Magazine, Vol. 20, No. 3, September 2013 (Impact factor: 1.77, Citations: 11)
Rajarajan Sivaraj , Amit Pande, Prasant Mohapatra, "Spectrum-aware Radio Resource Management for Scalable Video Multicast in LTE-Advanced Systems", in Proc. IFIP Networking, Brooklyn, NY, USA, May 2013 [Acceptance Rate: 25%. Citations: 8, Won IFIP and GGCS (UC Davis) travel grant awards][ PPT(pdf) ]
Rajarajan Sivaraj , Amit Pande, Kai Zeng, Kannan Govindan, Prasant Mohapatra, "Edge-prioritized Channel- and Traffic-aware Uplink Carrier Aggregation in LTE-Advanced Systems", in Proc. IEEE WoWMoM , San Francisco, CA, USA, Jun 2012 [Acceptance Rate: 22%. Citations: 25, Won NSF travel grant award][ PPTX ]
Rajarajan Sivaraj , Aravind Kota Gopalakrishna, M. Girish Chandra, P. Balamuralidhar, "QoS-based Group Communication in Integrated VANET-LTE Heterogeneous Wireless Networks", in Proc. IEEE WiMob , Shanghai, China, Oct. 2011 [Citations: 30][ ppt ]
Abderrahim Benslimane, Tarik Taleb, Rajarajan Sivaraj , "Dynamic Clustering-based Adaptive Mobile Gateway Management in integrated VANET-3G Heterogeneous Wireless Networks", IEEE Journal on Selected Areas in Communications (JSAC), Vol. 29, No. 3, pp. 559-570, Mar. 2011 (Impact factor: 3.5, Citations: 118)[ PPT ]
R. Manoharan, E. Ilavarasan, Rajarajan Sivaraj , "Adaptive Gateway Management in Heterogeneous Wireless Networks", International Journal of Research and Reviews in Ad Hoc Networks (IJRRAN), Vol. 1, No. 2, pp. 1-7, ISSN: 2046-5106, Jun. 2011
R. Manoharan, Rajarajan Sivaraj , S. Sashtinathan, K. Sriram, "A Novel Beyond 3G Architecture for Adaptive Gateway Management in Heterogeneous Wireless Networks", in Proc. IEEE WiMob , Marrakech, Morocco, Oct. 2009 [Citations: 19][ ppt ]
Teaching Assistant, EEC 173B - Design Projects in Computer and Communication Networks, Department of Electrical and Computer Engineering, UC Davis, June 2013 (Guest Lecturer for Reactive and Proactive MANET Routing Protocols).
Teaching Assistant, ECS 40 - Object-Oriented Programming and Software Development, Department of Computer Science, Spring 2012, UC Davis (Rating: 9.2/10 voted by 90 students)
Multi-Interface support for LTE user nodes in NS3 LENA, LTE Carrier Aggregation Module in NS3 LENA, Enhanced Inter-cell Interference (eICIC), with macro blanking support, for LTE-A in NS3 LENA, Log-normal Shadowing support (Mean = 0, SD = 6.5 dB) for Log-Distance path loss model between any UE-eNB pair for NS3 LENA Software (Dropbox Link) GitHub
Lab: 2104 Watershed Sciences, 426 La Rue Road South, Davis - 95616, CA, USA
Office: 2063 Kemper Hall, One Shields Avenue, Davis - 95616, CA, USA
Home: 1101 Village Dr., Apt 3, Belmont - 94002, CA, USA
email: rsivaraj AT ucdavis DOT edu © Rajarajan Sivaraj.