7th International Conference on Cognitive Radio Oriented Wireless Networks

Research Article

Comparison of Underlay and Overlay Spectrum Sharing Strategies in MISO Cognitive Channels

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  • @INPROCEEDINGS{10.4108/icst.crowncom.2012.248283,
        author={Ricardo Blasco-Serrano and Jing Lv and Ragnar Thobaben and Eduard Jorswieck and Adrian Kliks and Mikael Skoglund},
        title={Comparison of Underlay and Overlay Spectrum Sharing Strategies in MISO Cognitive Channels},
        proceedings={7th International Conference on Cognitive Radio Oriented Wireless Networks},
        publisher={IEEE},
        proceedings_a={CROWNCOM},
        year={2012},
        month={7},
        keywords={overlay underlay cognitive radio spectrum sharing multiple antenna},
        doi={10.4108/icst.crowncom.2012.248283}
    }
    
  • Ricardo Blasco-Serrano
    Jing Lv
    Ragnar Thobaben
    Eduard Jorswieck
    Adrian Kliks
    Mikael Skoglund
    Year: 2012
    Comparison of Underlay and Overlay Spectrum Sharing Strategies in MISO Cognitive Channels
    CROWNCOM
    IEEE
    DOI: 10.4108/icst.crowncom.2012.248283
Ricardo Blasco-Serrano1,*, Jing Lv2, Ragnar Thobaben1, Eduard Jorswieck2, Adrian Kliks3, Mikael Skoglund1
  • 1: School of Electrical Engineering and ACCESS Linnaeus Centre, KTH Royal Institute of Technology, Stockholm, Sweden
  • 2: Communications Theory, Communications Laboratory, Dresden University of Technology, Dresden, Germany
  • 3: Chair of Wireless Communications, Poznan University of Technology, Poznan, Poland
*Contact email: ricardo.blasco@ee.kth.se

Abstract

We consider an extension of the cognitive radio channel model in which the secondary transmitter has to obtain (``learn") the primary message in a first phase rather than having non-causal knowledge of it. We propose an achievable rate region that combines elements of decode--and--forward relaying with coding for the pure cognitive radio channel model. Moreover, we find the choice of parameters that maximize the secondary rate under a primary rate constraint. Finally, we compare numerically the performance of our system to that of an underlay scheme that combines beamforming, rate splitting, and successive decoding. We observe that although the overlay design provides higher rates, the losses due to the first phase are quite severe. In fact, for the considered scenarios, cleverly designed underlay schemes can provide comparable performance.