User Manual
Chapter 3 - Operation and Administration of the Macro BTS Managing BSs
4Motion 568 System Manual
3.9.12.2.3 Configuring the Airframe Downlink Diversity Mode Parameter
The system supports the following operation modes in the downlink:
MIMO Matrix A or B
Beam Forming
In MIMO Matrix A or B mode the system can use either MIMO Matrix A or Matrix
B. The selection between Matrix A and Matrix B is performed automatically for
each MS according to link conditions and supported MS capabilities.
MIMO Matrix A for Coverage Gain: In configuration with multiple transmit/receive
antennas, a single data stream is transmitted in parallel over multiple paths. A
mathematical algorithm known as Space Time Codes (STC) is used to encode the
data streams to make them orthogonal to each other. This improves the signal to
noise ratio at the receiver side, resulting in increased range and better throughput
for subscribers that are difficult to reach (e.g. deep indoors).
MIMO Matrix B for Increased Capacity: This flavor of MIMO, also known as
Spatial Multiplexing MIMO (SM-MIMO), sends an independent data stream over
each antenna. Thus, in case signal conditions are good, the data rate is increased
and in excellent conditions may be doubled.
Beam Forming mode is applicable only for 4x4 configurations (4-channels AU, 2x2
or 4x2 ODUs that support beam forming). The system learns the signals received
from each MS in each of the antennas, and adapt the transmitted signals
accordingly by sending the same data into radio signals at specific relative phases,
Beamforming creates a narrower antenna beam than that generated by a baseline
fixed-beam antenna, with the beam acting as a powerful adaptive directional
antenna. The signal with its transmitted energy is electronically formed and
directed to a particular subscriber, resulting in higher downlink gain for data,
greater downlink throughput and lower interference.
To configure the Airframe Downlink Diversity mode parameter, run the following
command:
npu(config-bs-66053-airframe)# dldiversity [mode < matrixAorB |
beamForming>]
IMPORTANT
When creating a new BS, the Airframe Downlink Diversity mode parameter must be configured
(even if configured to the default value).