Cisco BWX 8305 Installation And Commissioning Manual page 23

Chapter 3 Overview
Beamforming
The EMS is a set of software applications that the Service Provider uses to configure, communicate with,
and manage all the system elements directly related to the Broadband Wireless Access system. EMS
provides a single point for managing BWG-toBS, BWG-to-EMS, BS, and SS communications in a
WiMAX network.
The EMS is an IP-based element manager designed in a Server-Client relationship and runs on either
Windows or Solaris Operating Systems. Most Service Providers use the Client EMS Configuration &
Alarm Manager (CAM) application to interface with the system. All of the functions that can be
performed through the CAM can also be performed through a Command Line Interface (CLI), which is
a common computing language across platforms.
3.5 Beamforming
Cisco BWX 8305 Basestation antennas contain 8 elements (Figure 3-2), with a gain of 16 dB in the panel
configuration. Their combined effect is to concentrate the downlink data into a beam with maximum gain
at the location of each target SS (Figure 3-3).
Similarly, in the uplink the data transmitted by each SS is received by the 8 antenna elements with
different phases due to the differences in propagation distance from an SS to each antenna element. The
contributions from an SS are added up coherently after adjusting their phases for maximum gain. This
effect, which we call beamforming, is equivalent to having up to 18 dB of additional gain in the downlink
and up to 9 dB additional gain in the uplink. It allows the Cisco BWX Mobile WiMAX system to ate at
a much lower power level than would otherwise be necessary for the same results.
Figure 3-2 BWX 8305 Basestation Antenna
BWX 8305 Basestation Installation and Commissioning Guide
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