3G Americas has recently published an report: MIMO Transmission Schemes for LTE and HSPA Networks. The report is intended increases awareness and helps guide the deployment of MIMO technology in HSPA and LTE networks.
Multiple-input multiple-output (MIMO) technology is commonly defined as, the use of two or more unique radio signals, in the same radio channel, where each signal carries different digital information, or two or more radio signals that use beam forming, receive combining and spatial multiplexing (SM).
This report provides the principles behind smart antenna technologies such that the reader will be able to understand the fundamental tradeoffs. Report inludes many antenna configurations that can support a wide range of MIMO algorithms at the base station as well as extensively treat the issues behind the antenna configurations at the terminal. Report addresses the specific schemes selected by 3GPP to provide smart antenna capabilities in HSPA and LTE Rel-8.
Further it focuses on the expected standardization outcome in Rel-9 and Rel-10 and more specifically, in enhancements behind clustered linear arrays (CLA) and collaborative multipoint transmission/reception (CoMP) schemes. In addition it provides performance results for a wide variety of channel conditions, and antenna configurations for both DL and UL.
Based on simulation results presented in this report, it was shown that the relatively simple MIMO transmission scheme based on 2x2 CL SM, at low user equipment (UE) speeds can increase by 20% the DL sector spectral efficiency relative to a single antenna transmission, as well as increase the cell edge efficiency by approximately 35%.