MIMO systems with adaptive modulation

Zhendong Zhou, B. Vucetic
2004 IEEE 59th Vehicular Technology Conference. VTC 2004-Spring (IEEE Cat. No.04CH37514)  
Adaptive modulation (AM) schemes in multiple input multiple output (MIMO) systems with a perfect or imperfect channel state information (CSI) at both the transmitter and receiver were investigated. Under an average transmit power and instantaneous bit error rate (BER) constraint, the transmit parameters including the subchannel transmit power and/or spectral efficiency are optimally adapted in the spatial and/or temporal domain to maximize the average spectral efficiency (ASE). Two categories,
more » ... ). Two categories, the continuous rate and discrete rate, of adaptive systems were considered, where the derived asymptotic closed form expressions for the former provided much insight into the latter. Analytical and numerical results showed that a full multiplexing gain was achieved in variable rate variable power (VRVP) systems and variable rate (VR) systems. Variable power (VP) systems with unequal numbers of transmit and receive antennas also achieved the full multiplexing gain, unlike VP systems with equal number of transmit and receive antennas. The effect of CSI imperfection on the ASE and BER was evaluated for VR systems and closed form expressions for the ASE and BER were obtained. They prove to be a useful tool to assess the system performance without taking time consuming AM MIMO system simulations. Index Terms-Adaptive modulation (AM), channel state information(CSI), multiple input multiple output (MIMO) systems.
doi:10.1109/vetecs.2004.1388932 fatcat:33jepifoyvbdppu7asieitvlxu