Atec Anritsu-MT8221B - Manual (Page 11)

11
GSM/GPRS/EDGE Analyzers
The BTS Master features two GSM/GPRS/
EDGE measurement modes.
• RF Measurements
• Demodulation
The goal of these measurements is
to increase data rate and capacity by
accurate power settings, ensuring low
out-of-channel emissions, and good signal
quality. These attributes help to create a
low dropped call rate, a low blocked call
rate, and a good customer experience.
Cell site technicians or RF engineers can
make measurements Over-the-Air (OTA)
to spot-check a transmitter’s coverage
and signal quality without taking the cell
site off-line. When the OTA test results are
ambiguous one can directly connect to the
base station to check the signal quality
and transmitter power.
For easy identification of which cell you
are measuring the Base Station Identity
Code (BSIC) gives the base station ID,
the Network Color Code (NCC) identifies
the owner of the network, and the Base
Station Color Code (BCC) provides the
sector information.
Carrier-to-Interference (C/I)
C/I indicates the quality of the received
signal. It also can be used to identify areas
of poor signal quality. Low C/I ratios will
cause coverage issues including dropped
calls, blocked calls, and other handset
reception problems.
Phase Error
Phase Error is a measure of the phase
difference between an ideal and actual
GMSK modulated voice signal. High phase
error leads to dropped calls, blocked calls,
and missed handoffs.
Origin Offset
Origin Offset is a measure of the DC
power leaking through local oscillators and
mixers. A high Origin Offset will lower EVM
and Phase Error measurements and create
higher dropped call rates.
Power versus Time (Slot and Frame)
Power versus Time (Slot and Frame)
should be used if the GSM base station
is setup to turn RF power off between
timeslots. When used OTA, this
measurement can also spot GSM signals
from other cells. Violations of the mask
create dropped calls, low capacity, and
small service area issues.
BTS Master™ Base Station Analyzer Features
GSM/GPRS/EDGE Signal Analyzers (Options 0040, 0041)
RF Measurements
(Option 0040)
Channel Spectrum
Channel Power
Occupied Bandwidth
Burst Power
Average Burst Power
Frequency Error
Modulation Type
BSIC (NCC, BCC)
Multi-channel Spectrum
Power vs. Time (Frame/Slot)
Channel Power
Occupied Bandwidth
Burst Power
Average Burst Power
Frequency Error
Modulation Type
BSIC (NCC, BCC)
Demodulation
(Option 0041)
Phase Error
EVM
Origin Offset
C/I
Modulation Type
Magnitude Error
BSIC (NCC, BCC)
RF Measurement – Occupied Bandwidth
Excessive occupied bandwidth can create interference
with adjacent channels or be a sign of poor signal
quality, leading to dropped calls.
Demodulation – Error Vector Magnitude (EVM)
This is the single most important signal quality
measurement. Poor EVM leads to dropped calls, low
data rate, low sector capacity, and blocked calls.
RF Measurement – Average Burst Power
High or low values will create larger areas of cell-to-
cell interference and create lower data rates near cell
edges. Low values create dropouts and dead zones.
Pass/Fail Test
Set up common test limits, or sets of limits, for
each instrument. Inconsistent settings between base
stations, leads to inconsistent network behavior