Channel Measurements
The RBS measures BER (Bit Error Rate) and the signal strength over
each active channel per reporting period. All SACCH frames are
included in the measurements.
The reporting periods are different for different TNs, and for different
channels, and are the same as for the MS, defined in /GSM 05.08:8.4/.
The measurements of signal strength are referred to the RX reference
point. An R.M.S. (Root Mean Square) value is created for each burst.
Then, the logarithm of this value, expressed in dBm, is averaged over
the reporting period. The mapping of this average and RXLEV is as
defined in /GSM 05.08:8.1.4/.
The signal quality measurements are sampled per reporting period.
The mapping between BER and RXQUAL is as defined in /GSM
05.08:8.2.4/.
RBS calculates RXLEV_FULL, RXLEV_SUB, RXQUAL_FULL and
RXQUAL_SUB as an average of the frames as defined in the following
table:
Table 13 Frame calculation
Channel
combination
RXQUAL_FULL,
RXLEV_FULL
RXQUAL_SUB, RXLEV_SUB
(i) All TCH and SACCH frames (96
TCH, 4 SACCH)
8 SID + 4 SACCH
TCH/S: 8 SID + 4 SACCH(ii) All TCH and SACCH frames (48
TCH, 4 SACCH)
TCH/Data: 10 SID + 4 SACCH
(v), (vii) All SDCCH and SACCH frames
(8 SDCCH, 4 SACCH)
Same frames as for RXLEV_FULL
and RXQUAL_FULL
The SID frames for the TCH channels are defined in /GSM 05.08:8.3/.
Results from channel measurements are reported by A-bis message
MEASUREMENT_RESULT /GSM 08.58:8.4.8/.
10.3.2 Idle Channel Measurements
The RBS can perform signal strength measurements of disturbances on
all idle uplink dedicated channels.
The function is set to on or off on full rate or half rate basis when the
TS is configured by the BSC.
Measurements of signal strength are made over an averaging period.
The averaging period specifies the number of measurement periods
from which an average value is to be calculated. The averaging period
is specified for each TS by the BSC.
The measurements of signal strength are referred to the RX reference
point. An R.M.S. value is formed for each timeslot. The logarithm of
this value, expressed in dBm, is coded as defined for RXLEV in /GSM
05.08:8.1.4/. The average value is calculated from the RXLEV value,
After Initiation, a first average value is calculated after two completed
measurement periods. The second value is calculated when the first
averaging period is completed.
102 (306)
EN/LZT 123 2697 R5A
1998-08-13
© Ericsson Radio Systems AB
— All Rights Reserved —
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