Ranging Signal Designs for MIMO-OFDMA Systems

In this paper, we propose new ranging signal designs for time-division duplexing multiple input multiple output (MIMO) orthogonal frequency division multiple access (OFDMA) systems. Exploiting the channel knowledge from the downlink channel together with initial power control, we develop three ranging transmission schemes which provide multiuser and multi-antenna diversity gains and significant power saving for the subscriber stations. The advantages of the proposed approach over existing methods in terms of ranging performance, energy saving, and complexity saving are illustrated by analytical and simulation results.