Cognitive radio

A main aim in this area is to conduct research on cognitive radio technologies at radio access level in close collaboration with industry and country regulator and participate in relevant standardization bodies (e.g. P1900, ETSI RRS etc).

We have research expertise in spectrum sensing algorithms, cooperative sending mechanisms, dynamic spectrum allocations and sharing, signal processing for cognitive radio, white space modelling, coexistence of heterogeneous architectures, interference management in cognitive networks, reconfigurable architectures and green communications using cognitive radio.

The rapid increase in the number of wireless devices highlights the importance of intensive dynamic use of the available spectrum. The achievement of dynamic capacity concept will involve the development of new spectrum policies and regulations. The expected major enables for dynamic spectrum access techniques are Cognitive Radio (CR) systems. Cognitive radio is an intelligent radio potentially has the ability of self-reconfiguration and adaptation to the communication environment.

From the definition, the main functionalities required for the cognitive radio systems can be summarised as follows:

  • Spectrum Sensing: sensing and monitoring the available spectrum bands reliably to detect the unused portion of the primary user spectrum.
  • Spectrum Decision: the cognitive radio can allocate a channel based on the regularly policies and spectrum sensing results.
  • Spectrum Sharing: coordination among multiple cognitive radio users is needed to pre-vent the colliding in the available portion of the spectrum.
  • Spectrum Mobility: the cognitive radio user is regarded as visitor to the primary user spectrum, and a reliable communication cannot be sustained for a long time if the primary user uses the licensed spectrum frequently. Therefore, the cognitive radio system should support mobility to continue the communication in other vacant bands.

Collaborative Spectrum Sensing

One of the main challenges of CR is gaining spectrum awareness, thus being able to undertake reliable and sufficiently sensitive spectrum sensing. It enables the cognitive radio to be aware of and sensitive to the changes in its environments by detecting the white spaces in the primary user spectrum. In general, the spectrum sensing techniques can be broadly categorized into three groups: primary receiver detection, interference temperature management and primary transmitter detection. The research in this area focuses on:

  • Spectrum Sensing Algorithms
  • Collaborative Spectrum Sensing

Dynamic Spectrum Management (DSM)

The achievement of dynamic capacity concept will involve the development of new spectrum policies and regulations. Dynamic use of spectrum can improve spectrum utilisation and hence is a promising approach to satisfy increasing demand for spectrum. The research in ICS mainly focuses on:

  • Dynamic Load prediction algorithms
  • Cell-by-cell short term DSA for UMTS Multi-operator
  • Genetic Algorithm based DSA for wireless networks

Interference Management in CRN

Current research is in the area of:

  • Distributed power control (DPC) algorithms for CR
  • Joint rate and power control in cognitive femtocell
  • Antenna selection schemes for Cognitive Radio

Cognitive Radio Testbed

Our in house cognitive radio testbed includes the following features:

  • USRP hardware which includes
  • Ettus USRP motherboard
  • RFX2400 transceivers
  • Quad patch 2.4GHz antenna
  • 2 Linux workstations with GNU radio installed
  • WARP-based Cognitive Radio Testbed

Members of ICS have been extensively involved in the definition and execution of EU FP6/FP7 projects such as DRiVE/OVERDRiVE, WINNER, ROCKET, MOBILIFE, SPICE, ORACLE, E2R I/II, E3 and more recently in C2POWER and QoSMOS. We are also a key player in Mobile VCE and chair the IEEE standardisation group P1900.6.

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Institute for Communication Systems
James Clerk Maxwell building
University of Surrey