Mimo
Multiple-Input Multiple-Output Wireless Communication Systems Using Antenna Pattern Diversity
Liang Dong, Hao Ling, and Robert W. Heath, Jr. Department of Electrical and Computer Engineering The University of Texas, Austin, TX 78712
Abstract— Multiple-input multiple-output (MIMO) wireless communication systems employ multiple transmit and multiple receive antennas to obtain significant improvement in channel capacity. However, the capacity is limited by the correlation of subchannels in non-ideal scattering environments. In this paper, we investigate MIMO systems that use antennas with dissimilar radiation patterns to introduce decorrelation, hence increasing channel capacity. We develop a ray tracing model that takes into account both the propagation channel and the transmit and receive antenna patterns. Using a computational electromagnetic simulator, we show that: (1) MIMO systems that exploit antenna pattern diversity allow for improvement over dual-polarized antenna systems; (2) The capacity increase of such MIMO systems depends on the characteristics of the scattering environment.
I. I NTRODUCTION Multiple-input multiple-output (MIMO) wireless communication is one of the most promising technologies for improving the spectrum efficiency of wireless communication systems. It is well known that the use of MIMO antenna systems allows the channel capacity to scale in proportion to the minimum of the number of transmit and receive antennas in uncorrelated Rayleigh fading channels [1], [2]. Of course, real channels do not satisfy these ideal assumptions, thus recent work has focused on measuring and characterizing real MIMO propagation channels [3]. In parallel, work is continuing on efficient spacetime coding strategies that achieve the benefits of MIMO communication [4], [5]. However, thus far there has been little work on one of the most important aspects of MIMO communication systems – the antennas that are used at both the transmitter and receiver. The
Liang Dong, Hao Ling, and Robert W. Heath, Jr. Department of Electrical and Computer Engineering The University of Texas, Austin, TX 78712
Abstract— Multiple-input multiple-output (MIMO) wireless communication systems employ multiple transmit and multiple receive antennas to obtain significant improvement in channel capacity. However, the capacity is limited by the correlation of subchannels in non-ideal scattering environments. In this paper, we investigate MIMO systems that use antennas with dissimilar radiation patterns to introduce decorrelation, hence increasing channel capacity. We develop a ray tracing model that takes into account both the propagation channel and the transmit and receive antenna patterns. Using a computational electromagnetic simulator, we show that: (1) MIMO systems that exploit antenna pattern diversity allow for improvement over dual-polarized antenna systems; (2) The capacity increase of such MIMO systems depends on the characteristics of the scattering environment.
I. I NTRODUCTION Multiple-input multiple-output (MIMO) wireless communication is one of the most promising technologies for improving the spectrum efficiency of wireless communication systems. It is well known that the use of MIMO antenna systems allows the channel capacity to scale in proportion to the minimum of the number of transmit and receive antennas in uncorrelated Rayleigh fading channels [1], [2]. Of course, real channels do not satisfy these ideal assumptions, thus recent work has focused on measuring and characterizing real MIMO propagation channels [3]. In parallel, work is continuing on efficient spacetime coding strategies that achieve the benefits of MIMO communication [4], [5]. However, thus far there has been little work on one of the most important aspects of MIMO communication systems – the antennas that are used at both the transmitter and receiver. The