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S&C Instruction Sheet 1069-570
Overview
MIMO Radio
Technology
This reference guide provides the configuration guidelines needed to ensure optimum
system throughput performance.
All IntelliCom WAN Mesh Radios ship as 802.11a/b/g/n dual-radio-
capable hardware. Enhanced functionality is enabled through software licensing.
Applications that do not require 802.11n MIMO (Multiple Input Multiple Output) capacity,
or dual-radio capability can use the 802.11a/b/g-enabled single-radio configuration.
Dual-radio functionality can be enabled through a software license. A separate software
license can also enable MIMO functionality for operation in 40-MHz channels, allowing
users to take advantage of 802.11n technology for throughput of up to 300 Mbps outdoors
and 400 Mbps indoors.
MIMO (Multiple Input Multiple Output) technology is available only in the IntelliCom WAN
Mesh Radio. MIMO radios use multiple antennas at both the transmitter and receiver to
improve performance. MIMO significantly increases data throughput at the same transmit
power. It achieves this through higher spectral efficiency (more bits per second per hertz
of bandwidth) and link reliability or diversity (which reduces fading).
MIMO technology:
•
Doubles the spectrum of each channel from 20 MHz to 40 MHz, effectively
doubling throughput.
•
Uses
Spatial Multiplexing
to send multiple streams on a single channel.
IntelliCom radios send three streams per radio, which triples the bandwidth.
For the IntelliCom three-antenna (3x3) MIMO system (which sends two streams), the
data to be transmitted first passes through a specially designed mathematical matrix,
which divides it into three data streams. The transmitter then sends three streams
simultaneously, using multiple transmit antennas.
A three-antenna MIMO system is shown in Figure 1. In this case, the single data divided
into three streams is re-transmitted (or repeated) at antenna ports 2 and 3 to provide
transmission diversity. This approach sends the receiver multiple signals, allowing it to
select the strongest signal.
In Figure 1, nine signal paths are available. The receiver uses a complex mathemati-
cal matrix operation to determine which path has the best signal quality. With a 3X3
system, the receiver selects two of the three antenna data streams to use for processing
the signal. If you use a two antenna system, the receiver will use both antenna streams
to process the signal.
Figure 1. Three-antenna MIMO system.
Summary of Contents for IntelliCom
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