Maximum Ratio Combining; Antennas Supported - Cisco AIR-AP1251AG-A-k9 Hardware Installation Manual

Hardware Features
Spatial Multiplexing
The radio modules can support two transmitters to achieve higher data rates for a given bandwidth. This
technique is called multiple input multiple output (MIMO) and relies on the premise that, via muli-path,
two transmitted signals take different paths to the receivers. Using special data packet features allows
the receivers to distinguish between the two transmitted signals and increases the access point data rate.

Maximum Ratio Combining

The radio modules use three receivers to support maximum ratio combining (MRC) to enhance receiver
performance. MRC is a technique that combines the signals from multiple receivers in a manner to
optimize the signals. MRC can provide up to 3 dB of increased receive signal strength in all modes of
operation.

Antennas Supported

Table 1-1
Caution The access point, antennas, and all interconnected equipment must be located indoors within the same
building, including the associated LAN connections.
Note The access point has been designed to operate with the antennas listed below and having a maximum
gain of 10 dBi for 2.4 GHz and 6 dBi for 5 GHz. Antennas not included in this list or having a higher
gain are strictly prohibited for use with the access point. The required antenna impedance is 50 ohms.
Note To reduce potential radio interference to other users, the antenna type and its gain should be chosen so
that the equivalent isotropically radiated power (e.i.r.p.) is not more than required for successful
communication.
Table 1-1 Supported Antennas
2.4-GHz Antennas
1
AIR-ANT5959 diversity ceiling omnidirectional
AIR-ANT2422DG-R non-articulated dipole
AIR-ANT4941 articulating dipole
AIR-ANT2430V-R omnidirectional
AIR-ANT1728 ceiling omnidirectional
Cisco Aironet 1250 Series Access Point Hardware Installation Guide
1-6
C I S C O C O N F I D E N T I A L - D r a f t A 1
lists the supported access point antennas.
Gain
(dBi)
2
2.2
2.2
3
5.2
5-GHz Antennas
AIR-ANT5135DG-R non-articulated omnidirectional
AIR-ANT5135D-R articulating dipole
AIR-ANT5140V-R omnidirectional
1
AIR-ANT5145V-R diversity ceiling omnidirectional
1
AIR-ANT5160V-R omnidirectional
Chapter 1 Overview
Gain
(dBi)
3.5
3.5
4
4.5
6
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