An efficient probing mechanism for next generation mobile broadband systems

Abstract

Opportunistic scheduling exploits multiuser diversity for improving the performance of wireless systems. However, it requires instantaneous channel state information (CSI) to be available at the transmitter side. Since acquiring CSI is resource consuming, it always comes at a cost. We consider the problem of efficient channel state estimation in the context of 4G mobile broadband systems. Our proposed mechanism selects the subcarriers to be probed per user, by estimating the anticipated tentative rate with and without probing. For the latter an informed guess of the channel state is performed. The distinguishing characteristic of this work is that the channel state evolution is assumed Markovian, thus capturing the impact of mobility, contrary to the much simpler i.i.d. case hitherto considered. Based on this probing mechanism we derive a subcarrier allocation algorithm that aims at maximizing the sum rate of the system. Our simulations indicate that the proposed algorithm leads to significant performance benefits. © 2012 IEEE.