Specifications

Summit WM Getting Started Guide, Software Version 5.1 69
experience similar to wired networks while accessing high-bandwidth data, voice, and video
applications.
The Altitude 802.11n AP is available in the following two models:
● Altitude 450 – 3 internal antennas
● Altitude 451 – 3 internal antennas, RP-SMA connectors
MIMO
The pivot of 802.11 AP is MIMO (multiple input, multiple output) — a technology that uses advanced
signal processing with multiple antennas to improve the throughput. MIMO takes the advantage of
multipath propagation to decrease packet retries to improve the fidelity of the wireless network.
The 802.11n AP’s MIMO radio sends out three radio signals at the same time through its three radio
transceivers. Each of these signals is called a spatial stream. Each spatial stream is sent out from its own
transceiver, using its own antenna. Because the location of the antennas on the 802.11n AP is spaced out,
each spatial stream follows a slightly different path to the client devices. Furthermore, the three spatial
streams get multiplied into several streams as they bounce off the obstructions in the vicinity. This
phenomenon is called multipath. Since these streams are bounced from different surfaces, they follow
different paths to the client device. The client device, which is also 802.11n compliant, too has multiple
antennas. Each of the antennas independently decodes the arriving signal. Then each antenna’s decoded
signal is combined with the decoded signals from the other antennas. After a complex calculation via
the software algorithm, the result is much better signal and increased throughput.