Dr Vijay Subramanian

About me

I earned my degrees in two different continents: B. Tech. in Electronics Engineering in 1993 from the Indian Institute of Technology, Chennai, India , M.Sc.(Engg.) in Electrical Communication Engineering in 1995 from the Indian Institute of Science, Bengaluru, India, Ph.D. in Electrical Engineering in 1999 from the University of Illinois at Urbana-Champaign, Illinois, USA. After graduating I worked in the research arm of the Networks Business Sector of Motorola in Arlington Heights, Illinois, USA until May 2006. In May 2006 I moved to the Hamilton Institute of the National University of Ireland, Maynooth as a Research Fellow.

Research interests

My main research interests are in communications, information theory, stochastic modelling and applied mathematics. Most of my recent work has been on probabilitistic analysis of communication networks, especially analysis of scheduling and routing algorithms. Thanks to interesting visitors at the Hamilton Institute, I also have some interest in applications in immunology and coding of stochastic processes.

Copyright notice

Copyright belongs to the publisher in case of published articles. Copyright belongs to the authors or authors in all other cases.

Working articles

1. Vijay G. Subramanian and R. Agrawal.
   Convergence and Optimality of Opportunistic Scheduling Algorithms.
   July 2010.
2. A. Nedich, Vijay G. Subramanian.
   Approximately Optimal Utility Maximization.
   July 2010.

Book chapters

1. J. Huang, Vijay G. Subramanian, R. Berry and R. Agrawal.
   Scheduling and Resource Allocation in OFDMA Wireless Systems.
   Book Chapter in Orthogonal Frequency Division Multiple Access, Auerbach Publications, CRC Press, appeared April 2010.

Journal Papers Submitted

1. Vijay G. Subramanian and D.J.Leith.
   Convexity conditions for 802.11 WLANS.
   Submitted. July 2010.
2. D. J. Leith, Q. Cao and Vijay G. Subramanian.
   Max-min Fairness in 802.11 Mesh Networks.
   Submitted. March 2010.
3. X. Chen, Vijay G. Subramanian and D. J. Leith.
   PHY Modulation/Rate Control for Fountain Codes in 802.11 WLANs.
   Submitted to IEEE Trans. Wireless Comm. June 2009.
4. Vijay G. Subramanian, T. Javidi and S. Kittipiyakul.
   Many Sources Large Deviations of Max-Weight Scheduling.
   Submitted Feb 2009, under revision April 2010.
5. T. P. Coleman, N. Kiyavash and Vijay G. Subramanian.
   The Rate-Distortion Function of a Poisson Process with a Queueing Distortion Measure.
   Submitted May 2008, under revision.

Journal Papers Appeared

1. Vijay G. Subramanian.
   LDP for Max-Weight scheduling over convex compact rate-regions.
   Accepted to Mathematics of Operations Research, June 2010.
2. Vijay G. Subramanian, R. Berry and R. Agrawal.
   Joint scheduling and resource allocation in Downlink of CDMA systems.
   Appeared in IEEE Trans. on Information Theory, 56(5), 2416-2432, 2010.
3. D. J. Leith, Vijay G. Subramanian and K. R. Duffy.
   Log Convexity of Rate Region in 802.11e WLANs.
   Appeared in IEEE Comm. Letters, 14(1), 57-59, 2010.
4. V. Badarla, Vijay G. Subramanian and D. J. Leith.
   Low-delay Dynamic Routing Using Foutain Codes.
   Appeared in IEEE Comm. Letters, 13(7), 552-554, 2009.
5. Vijay G. Subramanian, K. R. Duffy and D. J. Leith.
   Existence and uniqueness of fair rate allocations in lossy wireless networks.
   Appeared in IEEE Transactions on Wireless Communications, 8(7), 3401-3406, 2009.
6. K. R. Duffy and Vijay G. Subramanian.
   On the impact of correlation between collaterally consanguineous cells on lymphocyte population dynamics.
   Published online Oct 2008, Journal of Mathematical Biology, Link.
   Appeared in Journal of Mathematical Biology, 59 (2), 255-285, 2009.
7. J. Huang, Vijay G. Subramanian, R. Agrawal and R. Berry.
   Joint scheduling and resource allocation in uplink OFDM systems for broadband wireless access networks.
   Appeared in IEEE JSAC Special Issue on Broadband Access Networks, Vol. 27:2, Feb 2009 Pages: 226--234.
8. J. Huang, Vijay G. Subramanian, R. Agrawal and R. Berry.
   Downlink scheduling and resource allocation for OFDM systems.
   Appeared in IEEE Trans. on Wireless Communications, Vol. 8:1, Jan 2009, Pages:288--296.
9. Vijay G. Subramanian, K. R. Duffy, M. L. Turner and P. D. Hodgkin.
   Determining the expected variability of immune responses using the Cyton Model.
   Appeared in Journal of Mathematical Biology, 56 (6), 861-892, June 2008.
10. B. Hajek and Vijay G. Subramanian.
    Broad-band fading channels: Signal Burstiness and Capacity.
    Appeared in IEEE Trans. on Information Theory Vol. 48:4, April 2002.
11. Vijay G. Subramanian, and B. Hajek.
    Capacity and Reliability Function for Small Peak Signal Constraints.
    Appeared in IEEE Trans. on Information Theory Vol. 48:4, April 2002.
12. Vijay G. Subramanian and R. Srikant.
    Tail probabilities of low-priority waiting times and queue lengths in MAP/GI/1 queues.
    Appeared in Queueing Systems Vol 34:1-4, 2000.

Funding/Travel Grants

1. Science Foundation of Ireland Short-Term Travel Fellowship 2009 - 3 month research visit to LIDS, MIT in 2010.

Conference submissions

Conference publications - Refereed and Invited

1. D. Vasudevan, Vijay G. Subramanian and D. J. Leith.
   Scheduling jobs with hard deadlines over Multiple Access and Degraded Broadcast Channels.
   to appear in Proceedings of IEEE International Symposium on Information Theory 2010, Austin, Texas, USA.
2. D. Vasudevan, Vijay G. Subramanian and D. J. Leith.
   On ARQ for Packet Erasure Channel with Bernoulli Arrivals.
   to appear in Proceedings of IEEE International Symposium on Information Theory 2010, Austin, Texas, USA.
3. D. J. Leith, Q. Cao and Vijay G. Subramanian.
   Realising Max-min Fairness in 802.11e Mesh Networks.
   Appeared in Proceedings of IEEE International Symposium on Wireless Pervasive Computing 2010, Modena, Italy.
4. H. Qi, D. Malone and Vijay G. Subramanian.
   Does every bit need the same power? An investigation on unequal power allocation for irregular LDPC codes.
   In Proceedings of International Conference on Wireless Communications and Signal Processing 2009, Nanjing, China.
5. A. Nedich, Vijay G. Subramanian.
   Approximately Optimal Utility Maximization.
   In Proceedings of IT Workshop 2009, Volos, Greece.
6. S. Kittipiyakul, T. Javidi and Vijay G. Subramanian.
   Many Sources Large Deviations of Max-Weight Scheduling.
   Considers the many sources LDP for max-weight scheduling with simplex rate region and non-idling server.
   In Proceedings of Allerton Conference 2008.
7. Vijay G. Subramanian and D. J. Leith.
   On a class of optimal rateless codes.
   Shows some interesting optimality properties of systematic equiprobable codes.
   In Proceedings of Allerton Conference 2008.
8. S. Bodas, S. Viswanath and Vijay G. Subramanian.
   Random Access Over Multiple Access Channels: A Queueing Perspective.
   High and intermediate SNR analysis of queueing capacity region of MIMO MAC region.
   Appeared in Proceedings of CISS 2008.
9. T. Coleman, N. Kiyavash and Vijay G. Subramanian.
   Alternate proof of rate-distortion function of a Poisson Process.
   Uses information theoretic inequalities and test-channel approach to prove rate distortion function of a Poisson Process.
   Appeared in Proceedings of DCC 2008.
10. Vijay G. Subramanian.
    Large Deviations Of Max-Weight Scheduling Policies On Convex Rate Regions.
    Proved an LDP for max-weight scheduling over general rate regions.
    Appeared in Proceedings of ITA 2008, UCSD.
11. Vijay G. Subramanian and Douglas J. Leith.
    Draining-time based scheduling algorithm.
    Alternate scheduling and routing algorithm proposal for networks, in contrast to max-pressure algorithms.
    Appeared in Proceedings of CDC 2007.
12. J. Huang, Vijay G. Subramanian, R. Berry and R. Agrawal.
    Scheduling and resource allocation for UL of OFDM systems.
    Solves the scheduling and resource allocation problem for the uplink of OFDM systems with a centralised scheduler. Optimal solution is tough to compute, hence simpler sub-optimal algorithms that don't sacrifice performance much are highlighted.
    Appeared in Proceedings of Asilomar 2007.
13. R. Agrawal, R. Berry, J. Huang and Vijay G. Subramanian.
    Scheduling and resource allocation for DL of OFDM systems.
    Solves the scheduling and resource allocation problem for the downlink of OFDM systems with self-noise formulating as a convex optimization problem.
    Appeared in Proceedings of Asilomar 2006.
14. J. Huang, Vijay G. Subramanian, R. Agrawal and R. Berry.
    Scheduling and resource allocation for DL of OFDM systems.
    Solves the scheduling and resource allocation problem for the downlink of a regular OFDM system formulating as a convex optimization problem.
    Appeared in Proceedings of CISS 2006.
15. R. Agrawal, Vijay G. Subramanian and R. Berry.
    Scheduling and resource allocation for DL of CDMA systems.
    Solves the scheduling and resource allocation problem for the downlink of a regular CDMA system formulating as a convex optimization problem.
    Appeared in Proceedings of WiOpt 2004.
16. R. Agrawal and Vijay G. Subramanian.
    Optimality of opportunistic scheduling algorithms.
    Using stochastic approximation showed the optimality of gradient-based scheduling for maximising utility of throughput.
    Appeared in Proceedings of Allerton Conference 2002.
17. R. Agrawal, A. Bedekar, R. La and Vijay G. Subramanian.
    Scheduling for DL of CDMA systems.
    Proposed algorithms for scheduling on the downlink of a regular CDMA system to maximise utility of throughput.
    Appeared in Proceedings of ITC 2001.
18. R. Agrawal, A. Bedekar, R. La, R. Pazhyannur and Vijay G. Subramanian.
    Scheduling for DL of TDMA systems.
    Proposed algorithms for scheduling on the downlink of a regular TDMA system to maximise utility of throughput.
    Appeared in Proceedings of SPIE 2001.
19. Vijay G. Subramanian and B. Hajek.
    Small signal capacity and reliability function.
    Appeared in Proceedings of CISS 2000.
20. B. Hajek and Vijay G. Subramanian.
    Capacity per unit fourthegy of WSSUS channels.
    Appeared in Proceedings of IT Workshop Kruger National Park 1999.
21. Vijay G. Subramanian and B. Hajek.
    Capacity per unit fourthegy of WSSUS channels.
    Appeared in Proceedings of CISS 1999.
22. Vijay G. Subramanian and R. Srikant.
    Tail probabilities of waiting times of low-proirity traffic.
    Appeared in Proceedings of CDC 1997.
23. Vijay G. Subramanian and U. Madhow.
    Blind demodulation of DS-CDMA signals using an antenna-array.
    Appeared in Proceedings of CISS 1996.

Presentations

1. Fair Throughput Allocation In Wireless Networks.
   Presentation at Deutsche-Telekom Labs, Technical University Berlin, Berlin, Germany, July 2010.
   

2. Large deviations of max-weight scheduling policies on convex rate regions.
   Presentation at Workshop on Stochastic Processes in Communication Sciences for Young Researchers, Edinburgh, UK, June 2010.
   

3. Large Deviations Of Max-Weight Scheduling Policies.
   Presentation at TREC, INRIA Paris-Roquencourt, France, March 2010.
   

4. An Analysis of the Cyton Model Using Branching Processes. Rather, What Can One Do With the Analysis?.
   Presentation at Workshop on B cell and Ageing: theoretical and experimental approaches, BBSRC MAT- SYB network I2M & BSI, School of Applied Mathematics, University of Leeds, Leeds, UK, March 2010.
   

5. Analyzing the Cyton Model of Immune Regulation: A Mathematical Approach to Immunology.
   Yale University, New Haven, ECE Dept., Feb. 2010
   

6. Approximately Optimal Utility Maximization
   University of California, San Diego, Information Theory and Applications, Feb. 2010.
   

7. Analyzing the Cyton Model of Immune Regulation: A Mathematical Approach to Immunology.
   University of Michigan, Ann Arbor, EECS Dept., Jan. 2010.
   

8. Large Deviations Of Max-Weight Scheduling Policies.
   Tata Institute of Fundamental Research (TIFR), Mumbai, India, School of Technology and Computer Science, Dec. 2009.
   

9. Large Deviations Of Max-Weight Scheduling Policies.
   Indian Institute of Science, Bangalore, India, ECE Dept., Dec. 2009.
   

10. Large Deviations Of Max-Weight Scheduling Policies.
    University of Minnesota, Minneapolis-St.Paul, ECE Dept., Nov. 2009.
    

11. The Rate Distortion function of a Poisson Process with a Queueing Distortion Measure.
    Presentation at 5th Workshop on Coding and Systems 2009 , University College Dublin, Dublin, Ireland, Sept 2009.
    

12. On a class of optimal rateless codes.
    Presentation at The Claude Shannon Workshop on Coding and Cryptography 2009 , Boole Centre, UCC, Cork, Ireland, May 2009.
    

13. Many-sources large deviations for Max-Weight Scheduling.
    Presentation at University of California, San Diego, Information Theory and Applications, Feb. 2009.
    

14. Many-sources large deviations for Max-Weight Scheduling.
    Presentation at YEQT-II , EURANDOM, Eindhoven, The Netherlands, Dec 2008.
    

Miscellaneous

1. Tutorial on Scheduling in Wireless Networks.
   Salient features of different opportunistic scheduling algorithms for broadcast channels - pointing out how all known algorithms maximise a weighted-sum of rates over current channel.
   Tutorial at IEEE VTC 2005, Dallas, TX.
   

2. Analysis of Multiuser Diversity in Wireless Networks.
   Analysis of different opportunistic scheduling algorithms. Presentation at INFORMS 2002, Boca Raton, FL.
   Abstract.
   

1. US Patent, Method and system for allocating subcarriers to subscriber devices, #7586990, Sept. 2009.
   

2. US Patent, Method and apparatus for resource allocation and scheduling, #7564820, Jul. 2009.
   

3. US Patent, Methods for dividing base station resources, #7558577, Jul. 2009.
   

4. US Patent, Variable reliability wireless communication transmission method and apparatus, #7539214, May 2009.
   

5. US Patent, Method and apparatus for improved channel maintenance signaling, #7492752, Feb. 2009.
   

6. US Patent, System and method for increased battery saving during idle mode in a wireless communication system, #7471942, Dec. 2008.
   

7. US Patent, Method to facilitate determination of a data rate, #7447154, Nov. 2008.
   

8. Japan/Korea Patent, Method and apparatus for resource allocation and scheduling, #JP3950460, Jan. 2007.
   

9. European Patent, Method for packet scheduling and radio resource allocation in a wireless communication system, #EP1227626, Oct. 2006.
   

10. US Patent, A method for packet scheduling and resource allocation in a wireless communication system, #6987738, Jan. 2006.
    

1. IEEE 802.16e, Handover triggers, Association procedures, May-June 2005.
   

2. IEEE 802.16g, Network Reference Model, Oct. 2004.
   

1. Technical Program Committee work:
   BroadWim 2004, IEEE WCNC 2006 PHY/MAC, RAWNET 2006 (along with WiOpt 2006), Globecom 2008 Wireless Networks Symposium, WICON 2008, MACOM 2009, ComNets 2010, INFOCOM 2010 WiP.