Reduced-Complexity RF Chain and Antenna Designs for Massive MIMO Transmitters

• Author / Creator

  Kasem, Ferhad

• The amount of mobile data handled by wireless broadband cellular networks is increasing explosively. Multiple-input multiple-output (MIMO) systems have gained a significant importance in modern wireless communication systems. MIMO offers many dimensional advantages that can be utilized to boost capacity and coverage without utilizing more bandwidth or transmit power. The introduction of MIMO systems with large antenna arrays (also known as massive MIMO) and the use of millimeter wave (mmWave) frequency bands are considered some of the key enabling technologies in the 5th generation of cellular systems to satisfy high data rate demands. However, when it comes to hardware implementation, massive MIMO systems with a large number of antennas face some challenges. Each antenna element is driven by a dedicated RF-chain; therefore, the RF-cost increases with the number of antennas. Each RF chain in a MIMO transmitter includes a power amplifier (PA), a mixer
  and a digital-to-analog converter (DAC). These components are expensive and power-consuming. Consequently, the cost will increase if the number of antennas grows. Reduced-cost MIMO systems have been drawing attention lately. In this
  dissertation, the hardware of a reduced-complexity and cost MIMO transmitter utilizing a single RF chain is presented. The RF chain includes a linear, low-cost, and energy-efficient PA and without the need for a mixer or DAC. This MIMO transmitter can convert digital signals in the baseband to the RF domain. In this MIMO transmitter, antennas are fed by two-port networks called load modulators. Load modulators are diode-based RF circuits that generate the desired outputs. The MIMO transmitter is designed at 3 GHz. The MIMO transmitter is capable of generating 64-QAM constellations at its output ports. This MIMO transmitter is perfectly suitable to operate with current MIMO receivers.

• Subjects / Keywords

  • MIMO
  • RF
  • Antennas
  • RF chain
  • Load Modulator
  • 64-QAM
  • Massive MIMO

• Graduation date

  Fall 2022

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/r3-6ntc-ms34

• License

  This thesis is made available by the University of Alberta Library 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.