This work presents an analytical model of the throughput-delay tradeoff found in proportional fair scheduling used in orthogonal frequency-division multiple access (OFDMA) systems in the context of user multiplexing. For this purpose, we propose a simple and efficient resource allocation scheme based on 2-D resource partitioning in the frequency and time domains. Basically, frequency-domain partitioning is determined by the degree of frequency diversity, and time-domain partitioning determines the degree of multiplexing (DoM), which is the number of users to be served in a subchannel of a frame. We investigate the effect of the DoM and frequency diversity on the delay quality-of-service (QoS) performance of OFDMA systems by analyzing the effective capacity. In addition, an energy efficiency analysis in the wideband regime shows that insufficient frequency diversity increases the impact of the delay QoS constraint on energy efficiency, and in this case, greater energy efficiency can be achieved by using an appropriate DoM.
Bibliographical noteFunding Information:
Manuscript received October 4, 2010; revised June 12, 2011; accepted July 22, 2011. Date of publication August 30, 2011; date of current version December 9, 2011. This work was supported by the National Research Foundation of Korea funded by the Korea government through the Ministry of Education, Science, and Technology under Grant 2010-0018938. This work was presented in part at the 2010 Asia-Pacific Conference on Communication, Auckland, New Zealand, October 31–November 3. The review of this paper was coordinated by Dr. H. Jiang.
All Science Journal Classification (ASJC) codes
- Automotive Engineering
- Aerospace Engineering
- Electrical and Electronic Engineering
- Applied Mathematics