Chapter 7 The AP340 Platform
72
Aerohive
Figure 5 Directional antenna patterns
Omnidirectional Antennas
You typically orient omnidirectional antennas vertically, positioning them on all devices in the same
direction. Omnidirectional antennas create coverage areas that can be toroidal (doughnut-shaped) or
cardioid (heart- or plum-shaped), broadcasting to the sides much more effectively than up or down (see
). In general, this is good for most office environments because you have large flat floors. However, it
can be a problem in environments with high ceilings.
Figure 6 Omnidirectional antenna radiation patterns
MIMO
MIMO (Multiple In, Multiple Out) is a major WLAN advancement introduced in the IEEE 802.11n standard in
which multiple RF links are formed on the same channel between the transmitter and receiver
simultaneously. To accomplish this, the transmitter separates a single data stream into multiple spatial
streams, one for each RF chain (an a various digital signal processing modules linked to the
antenna). The transmit antennas at the end of each RF chain then transmit their spatial streams. The
recipient’s receive antennas obtain streams from all the transmit antennas. In fact, due to multipath, they
receive multiple streams from each transmit antenna. The receive antennas pass the spatial streams to the
digital signal processors in their RF chains, which take the best data from all the spatial streams and
reassemble them into a single data stream once again (see
Higher gain
Lower gain
(Bird’s eye view)
Patch
antennas
Higher gain
Toroidal pattern Cardioid pattern
Содержание Aerohive AP141
Страница 1: ...Aerohive Hardware Reference Guide ...
Страница 7: ...Contents 6 Aerohive ...
Страница 17: ...Chapter 1 AP121 and AP141 Platforms 16 Aerohive ...
Страница 31: ...Chapter 2 The AP170 Platform 30 Aerohive ...
Страница 49: ...Chapter 4 AP330 and AP350 Platforms 48 Aerohive ...
Страница 63: ...Chapter 6 BR200 and BR200 WP Routers 62 Aerohive ...
Страница 107: ...Chapter 10 The High Capacity HiveManager 106 Aerohive ...
Страница 111: ...Index 110 Aerohive ...