Beamforming for underlay two-way relay networks

• Author / Creator

  CAO, Yun

• Although underlay networks mitigate the dual problems of spectrum congestion and spectrum under-utilization, the bi-directional (primary-to-secondary and secondary-to-primary) interference issues must be addressed to improve their reliability, coverage and capacity. To address these problems, this thesis investigates beamforming and two-way relaying. Specifically, the two underlay configurations considered are (a) multi-antenna terminals and one single-antenna two-way relay and (b) single-antenna terminals and multiple single-antenna two-way relays. First, for Configuration (a), assuming the availability of perfect channel state information, the performance of sub-optimal beamforming algorithms is characterized. Specifically, the exact and asymptotic outage probabilities in high transmit power and interference temperature limit region are derived considering both path loss effect and small-scale fading. Second, also for Configuration (a), efficient transmitter and receiver beamforming strategies are developed, e.g., transmit powers, transmitter-side beamforming and receiver-side beamforming vectors at the two multi-antenna terminals. Third, for Configuration (b), assuming the availability of second-order channel statistics, the joint relaying and transmitter designs are developed.

  Overall, these research findings show the capability of beamforming and relaying in addressing the bi-directional interferences problems in underlay networks and thus improving their reliability.

• Subjects / Keywords

  • Underlay Cognitive Radio
  • Two-Way Relay
  • Beamforming

• Graduation date

  Fall 2015

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3MC8RN2V

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.