【资料名称】：MIMO in LTE Operation and Measurement-Ex

【资料作者】：安捷伦

【资料日期】：2009

【资料语言】：中文

【资料格式】：DOC

【资料目录和简介】：

This application note is written for people who need an understanding of
Multiple Input Multiple Output (MIMO) radio operation as it applies to Long
Term Evolution (LTE). MIMO (otherwise known as spatial multiplexing) is one
of several multiple antenna techniques that are being implemented in LTE;
however, this application note will primarily focus on MIMO implementations.
Increasing use of high-bandwidth applications (such as streaming video) drives
a continued desire for higher throughput or better coverage from wireless
systems. To some extent, the use of more complex modulation formats such as
Orthogonal Frequency Division Multiplexing (OFDM) and 64 QAM has satisfied
this need. Other optimizations have been made through multiple antenna
techniques, including the use of more than one antenna, receiver chains that
combine multipath signals and multiple base station antennas correlated in
phase to shape coverage area.
Further advances are continually being made. Changing the use of the spectrum
available is being pursued through several approaches, including MIMO.
Release 8 of the 3GPP specifications, which specifies the Long Term Evolution
towards 4th generation (4G) systems (LTE), includes new requirements for
operation, where a base station and handset communicate using two or more
transmit and receive chains and takes advantage of the differences in radio
transmission paths between them.The goal is to increase both overall capacity
of a cell and the data rate that a single user can expect from the system.
MIMO radios get more from the RF bandwidth they occupy than their single-
channel equivalents by exploiting differences in the paths between the
transmitter and the receiver inputs. If a conventional single-channel radio
system creates one data “pipe” between the transmitter and the receiver, the
object of a MIMO radio system is to create multiple such pipes. It does this
by creating a mathematical model of the paths from transmitters to receivers
and solving the resulting equations, and has to do so as fast as the channel is
changing. If the data pipes can be completely separated, the channel capacity
increases linearly as more transmitter-receiver pairs are added.
The radio environment does not give up increases in capacity easily. MIMO
radio operation relies on the ability to separate the “pipes”. Like a solution to
a mathematical puzzle, there have to be enough equations compared to the
number of unknowns. This is added to the usual requirements to deal with
matters of interference, noise, interoperability, hardware costs and current
consumption.
Testing will play an important role in helping to make sure the radios operate
correctly, both individually and between the many different vendors’ designs
that will be deployed.