Cognitive Software-Radio Enabled Fair Spectrum Access in Open Spectrum Systems

Wireless devices are becoming ubiquitous, placing increasing stress on the fixed radio spectrum available to all access technologies. To eliminate interference between different wireless technologies, current policies allocate a fixed spectrum slice to each technology. This static assignment prevents devices from efficiently utilizing allocated spectrum, resulting in spectrum holes (no targeted devices in local area) and very poor utilization (6-10%) in other geographic areas(DARPA source). Studies have shown that reuse of such "wasted" spectrum can provide an order of magnitude improvement in system capacity. These results further motivate the Open Spectrum approach to spectrum access. Enabled by software defined radio (SDR) technology, Open Spectrum allows unlicensed (secondary) users to share spectrum with legacy (primary) spectrum users, thereby "creating" new capacity and commercial value from existing spectrum ranges. Based on agreements and constraints imposed by primary users, secondary users opportunistically utilize unused licensed spectrum on a non-interfering or leasing basis.

The Open Spectrum approach to spectrum access can achieve near-optimal utilization by allowing devices to sense and utilize available spectrum opportunistically. However, a naive distributed spectrum assignment can lead to significant interference between devices. In this series of work, we define a general framework that defines the spectrum access problem for several definitions of overall system utility.

Collaboration requires coordination among devices. We have proposed a distributed coordination framework for open spectrum systems. See HD-MAC project for more details.

Collaboration and Fairness in Opportunistic Spectrum Access
Haitao Zheng, Chunyi Peng
IEEE International Conference on Communications(ICC)2005
Korea, May,2005
Also as MSR Technical Report, Feb. 2005 [Abstract , PDF ]

Utilization and Fairness in Spectrum Assignment for Opportunistic Spectrum Access
Chunyi Peng, Haitao Zheng, Ben Y. Zhao
accepted by ACM Monet [Abstract  ]

Distributed Spectrum Allocation via Local Bargaining
Lili Cao, Haitao Zheng
accepted by IEEE SECON 2005 PDF [Abstract]

Device Centric Spectrum Management
Haitao Zheng, Lili Cao
accepted by IEEE Dyspan 2005 PDF [Abstract]

Talks: coming soon!
Haitao Zheng, August 8, 2005