[1] S. Mathur, L. Sankar, N. B. Mandayam, “Coalitions in Cooperative Wireless Networks” in IEEE JSAC, Special issue on Game Theory in Communications Systems” vol 26, pp. 1104-1115, September 2008.

[2] O. Ileri, and N. B. Mandayam, “Dynamic Spectrum Access Models: Towards an Engineering Perspective in the Spectrum Debate” in IEEE Communications Magazine, vol. 46, No. 1, pp. 153-160, January 2008.

[3] C. Raman, J. Singh, R. D. Yates, N. B. Mandayam, “Scheduling in Cognitive Networks” in Cognitive Wireless Networks, pp. 285-306, Springer, 2007 (BOOK CHAPTER).

[4] O. Ileri, D. Samardzija, and N. B. Mandayam, “Dynamic Property Rights Spectrum Access: Flexible Ownership Based Spectrum Management”, Proceedings of IEEE DySpan Conference, Dublin, Ireland, April 2007.

[5] O. Ileri, D. Samardzija, T. Sizer and N. B. Mandayam, “Demand Responsive Pricing and Competitive Spectrum Allocation via a Spectrum Policy Server”, Proceedings of IEEE DySpan Conference, Baltimore, MD, November 2005. [PDF]

[6] O. Ileri, S. Mau and N. Mandayam, “Pricing for Enabling Forwarding in Self-Configuring Ad-Hoc Networks”, IEEE JSAC, Special Issue on Wireless Ad Hoc Networks, Vol. 23, No. 1, pp. 151-162, January 2005. [PDF]

[7] J. Acharya, R. D. Yates, “A price based dynamic spectrum allocation scheme”, Accepted for publication in Asilomar Conf. on Signals, Systems and Computers, 4-7th November, 2007 in Pacific Grove, California

[8] J. Acharya and R. Yates, "A Framework for Dynamic Spectrum Sharing between Cognitive Radios, To appear in the Conference Proceedings of ICC 2007, Glasgow, Scotland, June 2007.

[9] J. Acharya, R. D. Yates, “Profit maximizing pricing strategies for dynamic spectrum allocation”. In Proc. of IEEE Conf. on Information Sciences and Systems (CISS), 14-16th March 2007, Baltimore.

[10] J. Singh, C. Raman, R. Yates and N. Mandayam, "Random Access for Variable Rate Links," IEEE MILCOM, Washington, DC, October 2006. pp. 1-6. [PDF]

[11] R. D. Yates, C. Raman and N. B. Mandayam, “Fair and Efficient Scheduling of Variable Rate Links Via a Spectrum Server,” Proceedings of IEEE International Communications Conference (ICC 2006), Istanbul, Turkey, Jun 11-15, 2006.

[12] C. Raman, R. D. Yates, N. B. Mandayam, “Cross-layer Scheduling of End-to-End Flows Using a Spectrum Server,” in Proceedings of the Conference of Information Sciences and Systems (CISS 2006), Princeton, NJ, Mar 22-24, 2006.

[13] C. Raman, R. Yates and N. Mandayam, "Scheduling variable Rate Links with a Spectrum Server", IEEE DySpan Conference, Baltimore MD, November 2005, pp. 110-118. [PDF]

[14] J. Singh and C. Rose, “Channel Probing Under a Power Budget”, CISS’06, Princeton, March 2006.

[15] D. C. Popescu, O. Popescu, and C. Rose. Interference Avoidance and Multiaccess Vector Channels. IEEE Transactions on Communications, vol. 55, no. 8, pp. 1466-1471, August 2007.

[16] O. Popescu, D. C. Popescu, and C. Rose. Simultaneous Water Filling in Mutually Interfering Systems. IEEE Transactions on Wireless Communications, vol. 6, no. 3, pp. 1102 - 1113, March 2007.

[17] D. C. Popescu and C. Rose. Codeword Optimization for Uplink CDMA Dispersive Channels. IEEE Transactions on Wireless Communications, vol. 4, no. 4, pp. 1563 - 1574, July 2005.


Dynamic Spectrum Algorithms

Project Objectives:
Spectrum regulation has traditionally been driven by improvements in technology, from improved filters to the sophisticated logic and radio techniques that created the cellular revolution. More recently, however, a new paradigm has emerged in which regulation has driven technology. A modest regulatory experiment in “open spectrum” that began in the ISM bands has spawned an impressive variety of important technologies and innovative uses, from cordless phones and wireless LANs to meter readers and home entertainment products. Since these systems must adapt to a wide variety of unpredictable conditions, the emerging technologies called “cognitive radio” can offer significant potential benefits in system capacity and service quality.

Technology Rationale:

Ultimately, the capacity of the open access bands, and the quality of service they can offer, will depend on the degree to which radios can be designed to adapt to a wide variety of conditions, some of which cannot yet be predicted. For this reason, the emerging technologies that have been called “cognitive radio” are particularly relevant to the open and dynamic spectrum access debate. The cognitive approaches being studied here represent a range of options that encompass methods for discovery and facilitation, as well as competition and collaboration. Further, they also represent a range of cognitive options that are associated with varying levels of hardware and protocol complexity. These approaches are being studied using a combination of fundamental analysis, computer simulation and physical emulation using testbeds already being developed at WINLAB.

Technical Approach:
The advances in cognitive radio platform development including the WiNC2R platform at WINLAB are bringing closer to reality the assumption that a perfect cognitive radio exists and can configure itself to any transceiver type. Under this assumption, a number of exemplary cognitive strategies are being studied to identify the approaches which offer the greatest benefits. These strategies include:

• discovery of available spectrum,
• information servers and mechanisms to support
efficient operation,
• incentive mechanisms for cooperation,
• negotiation in situations of conflict,
• coding for efficient sharing, and
• domination in situations of conflict.

More recently, we have also begun exploring the impact of cognitive radios and dynamic spectrum access on shaping spectrum policy. The most notable aspects of this project have been infusing an engineering perspective into the spectrum policy debate between proponents of “open access” and “spectrum property rights” regimes. Specifically, relating communication theoretic performance measures to spectrum governance regimes as well concepts from microeconomics allows two breakthroughs: (1) Modeling of user preferences, operator competition, and the advanced wireless access technologies used; and (2) Evaluating the relevant quantitative performance measures under different spectrum governance regimes, allowing for more tangible comparative analysis that goes beyond rhetoric.


Results To Date and Future Work Plan:
Funded by the NSF, this program is identifying features that are essential for a good cognitive radio, and in doing so, bring the goal of a realizable cognitive radio closer to reality. Specific projects being studied here include:

• Cognitive Radio Protocols and Algorithms for Open Access:
Design of algorithms and protocols for frequency selection, coordination and cooperation among neighbor nodes in a cognitive radio network. Exploration of the role of coalitional games in cooperative transmission.

• Network Information Servers for Open Access:
Design of “spectrum servers” that can determine neighborhood and interference information from (potentially anonymous) access point/mobile measurements and reporting, and enable efficient spectrum coordination.

• Cooperative Forwarding for Spectrum Sharing:
Pricing and game theoretic strategies for incentivizing and enabling cooperation and forwarding, with the added notions of both reputations and virtual currencies to enable open access to spectrum. Exploration of alleviating costs of cooperative transmission via incentive mechanisms based on “barter” exchange of physical transmission commodities such as bandwidth and time.

• Cooperative Coded Transmission for Spectrum Sharing:
Cooperative diversity and coding techniques with varying degrees of cognitive awareness and capabilities, for increased spectrum utilization.

• Spectrum Warfare with Agile Waveforms:
Primitive distributed control actions and waveform adaptation to strategically teach autonomous radiating nodes in a system to more efficiently share spectrum resources.

Further, the results of this research are of immediate relevance for practitioners in industry, for the large potential user community, and for the civilian and military branches of the government. These results will continue to be disseminated via workshops for practitioners from the private and public sectors, including participants from the Federal Communications Commission, DARPA, and state and local governments interested in the potential benefits of open access to spectrum.


Prof. Narayan Mandayam
732-932-6857 Ext. 642   

Revelent Grants:

National Science Foundation (NSF) grant awarded to WINLAB:
“Cognitive Radios for Enabling Open Access to Spectrum”
PI: Prof. Narayan Mandayam

National Science Foundation (NSF) grant awarded to WINLAB:
“Cooperation and Conflict: Coalitional Games in Spectrum Sharing”

PI: Prof. Narayan Mandayam

National Science Foundation (NSF) grant awarded to WINLAB:
“A Joule for your Byte: Barter-Exchange Incentive Mechanisms for Wireless Networks”

PIs: Prof. Roy Yates and Prof. Narayan Mandayam


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