Effect of antenna separation on the capacity of BLAST in correlated channels.pdf

IEEE COMMUNICATIONS LETTERS, VOL. 4, NO. 11, NOVEMBER 2000 337 Effect of Antenna Separation on the Capacity of BLAST in Correlated Channels Dimitry Chizhik, Farrokh Rashid-Farrokhi, Jonathan Ling, and Angel Lozano, Member, IEEE Abstract—As the base station is usually placed above local of the signals received by antennas and , separated by distance clutter, the angular spectrum incident on the base is narrow, , and illuminated by an angular spectrum is [3]. inducing correlation among base antenna signals, which reduces the capacity of a multiple transmit and receive antenna systems. In this work the general expression for link capacity is derived, when there is correlation among receive antennas and among transmit antennas. It is found that an antenna separation of 4 (1) wavelengths between nearest neighbors in a linear base array of dually polarized antennas allows one to achieve 80% of the where is the azimuth angle of incidence of each plane wave; capacity attainable in the uncorrelated antenna case. is the wavenumber at the angular frequency ; and is the angle of orientation of the linear array, set to be 90 for I. INTRODUCTION the broadside array considered here. In the case of uniform il- lumination and , where is the LAST (Bell-labs LAyered Space–Time) is a communica-