In this paper, we propose two different types of downlink scheduling scheme based on assembling the schemes of 1) the switch-and-examine scheduling in the network layer and 2) the joint adaptive modulation and output-threshold maximum ratio combining (OT-MRC) in the physical layer and, thus, attempt to find an efficient cross-layer access scheme to exploit the user diversity as well as the high spectral efficiency and the antenna diversity gain. We consider a multiuser environment in which each base station (BS) equipped with a single antenna attempts to communicate with each user equipped with an L-finger RAKE receiver based on switch-and-examine transmission (SET) as a user selection-scheduling scheme. We propose two different SETs, i.e., spectrally efficient SET and feedback load-efficient SET. We analyze the performance of our proposed schemes and compare them with the optimal scheduling scheme in terms of average spectral efficiency and average number of estimated paths per user to quantify the complexity.
Bibliographical noteFunding Information:
Manuscript received May 29, 2007; revised November 26, 2007 and June 6, 2008. This work was supported by the Center for Broadband OFDM Mobile Access (BrOMA) at POSTECH through the ITRC program of the Korean MIC, supervised by IITA under Grant IITA-2005-C1090-0502-0008. This paper was presented in part at the IEEE Vehicular Technology Conference (VTC’07), Dublin, Ireland, April 2007. The review of this paper was coordinated by S. Cui.
- Adaptive modulation
- Cross-layer optimization
- Diversity techniques
- Downlink scheduling scheme
ASJC Scopus subject areas
- Automotive Engineering
- Aerospace Engineering
- Electrical and Electronic Engineering
- Applied Mathematics