Cognitive Networking
▶ Introduction
 

The explosive traffic increase of ubiquitous wireless services over the past several years illustrates the huge and growing demand for bandwidth. Spectral shortage and inefficient spectral usage has been forced to address in order to adaptively accommodate the exponential demand on spectrum access, efficiency and reliability. Cognitive radio (CR), a new communication paradigm relaxing the radio spectrum scarcity, has been considered as a promising technology for realizing dynamic spectrum access (DSA). Many standardization activities such as IEEE 802.22, ECMA 392, IEEE SCC41, and IEEE 802.11af have recently been released for potential CR applications.

The research field of Cognitive Radio Networks will focus on the newly emerging wireless communications and networking technologies, which aim at mitigating the problem of the spectrum underutilization, energy inefficiency, unfairness of resource allocation, channel outage, and unreliable path in dynamic spectrum access networks. We are improving the interoperability and coexistence among different wireless/mobile communications systems, and making the future wireless network generation become autonomous and self-reconfigurable. Specifically, the distributed/mobile multi-hop architecture with the time/location-dependent spectrum availability is one of our key interests. The current research challenges of the CRNs are addressed from the following viewpoints:

  • Spectrum Sensing/Management: The cognitive users (CUs) seek spectrum opportunities overover a wide frequency range by detecting/monitoring and making decision for their best transmission without downgrading the licensed users (LUs) QoS.
  • Cross-layer optimization Protocols: To ensure reliable end-to-end delivery and obtain fair/efficient dynamic resource allocation, the interaction relationship among higher layershelps CUs balance between bandwidth demand and capacity supply to optimize interference, energy and interference.


  • Fig. 1. Interaction relationship of rate control, power control, and spectrum management


    ▶ Research Issues

     
  • Joint power-controlled MAC and congestion control scheme for fading channels in cognitive radio networks.
  • Performance evaluation of multi-hop cognitive radio networks for interference constraint and outage constraint.
  • Cross-layer optimization design for congestion control, power control and relay selection in cooperative cognitive radio networks.
  • Joint Optimal Rate-Power-Controlled Multi-Channel MAC Design For OSA-Based Multi-hop Cognitive Radio Networks.
  • Delay-limited Scheduling in Multi-hop Cognitive Radio Networks.


  • ▶ References

     


    ▶ Achievements

     
    1. Cuong T. Do, Nguyen H. Tran, Mui Van Nguyen, ChoongSeon Hong, Sungwon Lee, "Social Optimization Strategy in Unobserved Queueing Systems in Cognitive Radio Networks", IEEE Communications Letters (accepted for publication, 2012)
    2. Mui Van Nguyen, Sungwon Lee, ChoongSeon Hong, "Joint Rate Adaption, Power Control, and Spectrum Allocation in OFDMA-Based Multi-hop CRNs", IEICE Transactions on Communications(accepted for publication, 2012)
    3. Mui Van Nguyen, ChoongSeon Hong, Sungwon Lee, "Cross-Layer Optimization for Congestion and Power Control in OFDM-Based Multi-hop Cognitive Radio Networks", IEEE Transactions on Communications, VOL. 60, NO. 8, pp. 2101 - 2112, August, 2012
    4. Mui Van Nguyen, Trung Q. Duong, ChoongSeon Hong, Sungwon Lee, and Yan Zhang, “Optimal and Sub-Optimal Resource Allocation in Multi-hop Cognitive Radio Networks with Primary User Outage Constraint”, IET Networks, Vol. 1, Iss. 2, pp. 47?57, June 2012
    5. Cuong T. Do, Nguyen H. Tran, ChoongSeon Hong and Sungwon LEE, "Finding an Individual Optimal Threshold of Queue Length in Hybrid Overlay/Underlay Spectrum Access in Cognitive Radio Networks", IEICE Transactions on Communications, Vol.E95-B, No. 06, pp.1978-1981, June 2012
    6. ZawHtike, Jun Lee, ChoongSeon Hong and Sungwon Lee, "A Hybrid MAC Protocol for Cognitive Radio Ad Hoc Networks", IEICE Transactions on Communications Vol.E95-B, No. 04, pp.1135-1142, April 2012
    7. Nguyen H. Tran, ChoongSeon Hong and Sungwon Lee, "Utility Maximization with Packet Collision Constraint in Cognitive Radio Networks", IEICE Transactions On Communications, Vol.E95-B, No.1, pp.321-324, January 2012
    8. Cuong T. Do, ChoongSeon Hong, Jinpyo Hong, "Pricing Control for Hybrid Overlay/Underlay Spectrum Access in Cognitive Radio Networks", The 14th Asia-Pacific Network Operations and Management Symposium(APNOMS 2012), September 25-27(27), 2012, Seoul, Korea
    9. Mui Van Nguyen, and ChoongSeon Hong, "Joint Optimal Rate, Power, and Spectrum Allocation in Multi-hop Cognitive Radio Networks", IEEE Internationnal Conference on Communications(ICC 2012), June 10-15(13), 2012, Ottawa, Canada
    10. Cuong T. Do, Nguye H. Tran, ChoongSeon Hong, "Optimal Queueing Control in Hybrid Overlay/Underlay Spectrum Access in Cognitive Radio Networks" , 2012 IEEE 75th Vehicualr Technology Conference (VTC 2012), 6-9 May, Yokohama, Japan
    11. Jun Lee, Thant ZinOo, Sungwon Lee, ChoongSeon Hong and Heeyoung Jung, "Design of Handover Scheme for IEEE 802.22 WRAN", 2012 International Conference on Ubiquitous Information Management and Communication (ICUIMC 2012), February 20-22(21) 2012, Kuala Lumpur, Malaysia
    12. ZawHtike, Jun Lee and ChoongSeon Hong, "A MAC Protocol for Cognitive Radio Networks with Reliable Control Channels Assignment", The International Conference on Ingormation Networking 2012(ICOIN 2012), February 1-3(2) 2012, Bali, Indonesia
    13. Cuong T. Do, Nguyen H. Tran and ChoongSeon Hong, "Throughput Maximization for The Secondary User over Multi-channel Cognitive Radio Networks", The International Conference on Ingormation Networking 2012(ICOIN 2012), February 1-3(2) 2012, Bali, Indonesia
    14. Mui Van Nguyen, ChoongSeon Hong and Il Kwon Cho, "Joint Rate Adaption, Power Control, and Spectrum Allocation for OFDMA-Based Multi-hop CRNs", International Conference on ICT Convergence(ICTC2011) September 28-30, 2011, Seoul, Korea
    15. Nguyen Van Mui and ChoongSeon Hong, "A Cross-Layer Design for Resource Allocation and Congestion Control in Multichannel Multi-hop Cognitive Radio Networks", International Conference on Ubiquitous Information Management and Communication(ICUIMC 2011) February 21-23, 2011, Seoul, Korea