Sum Rate Analysis of a Reduced Feedback OFDMA Downlink System Employing Joint Scheduling and Diversity

  • Authors:

  • Seong-Ho Hur;Bhaskar D. Rao

  • Affiliations:

  • Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, USA;Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, USA

  • Venue:
  • IEEE Transactions on Signal Processing
  • Year:
  • 2012

Quantified Score

Hi-index 35.68

Visualization

Abstract

We consider joint scheduling and diversity to enhance the benefits of multiuser diversity in an orthogonal frequency-division multiple access (OFDMA) downlink system. The OFDMA spectrum is assumed to consist of $N_{\rm RB}$ resource blocks and the reduced feedback scheme consists of each user feeding back channel quality information (CQI) for only the best-$N_{\rm FB}$ resource blocks. Assuming largest normalized CQI scheduling and a general value for $N_{\rm FB}$, we develop a unified framework to analyze the sum rate of the system for both the quantized and nonquantized CQI feedback schemes. Based on this framework, we provide closed-form expressions for the sum rate for three different multiantenna transmitter schemes; transmit antenna selection (TAS), orthogonal space time block codes (OSTBC) and cyclic delay diversity (CDD). Furthermore, we approximate the sum rate expression and determine the feedback ratio $\left(N_{\rm FB}\over {N_{\rm RB}}\right)$ required to achieve a sum rate comparable to the sum rate obtained by a full feedback scheme.