Startup Of Master Ipbs; Sync Backup Master - ASCOM IP-DECT Base Station Installation And Operation Manual

Installation and Operation Manual
IP-DECT Base Station & IP-DECT Gateway
Figure 48.
FER value Description
< 90
> 90
= 100

Startup of Master IPBS

When a master starts up it searches for other IPBSs within the same system during 30
seconds. If any IPBS is found the values for slot, frame, multiframe and PSCN is received
and applied to the master. After receiving all these values or after the timeout of 30
seconds the master enters the master state.
In master state the values are updated locally during all further operation of the master
IPBS and no synchronization to other IPBSs in the same system is done.
With this method it will be possible to restart only the master in the system. The remaining
slaves will be able to maintain synchronization for a few minutes during restart of the
master. The master will adjust itself to the other base stations at startup. The slaves will
notice the master is back and the sync will be received from the master.
If no IPBS within the same system is detected during the first 30 seconds at startup initial
values will be selected and the IPBS will enter master state with these values.

Sync Backup Master

Only one sync master base station needs to be configured for a system. But if this single
base station fails the entire system will fail. It is therefore possible to configure a sync
backup master base station in the system.
If one or several backup master base stations are configured these base stations must be
positioned next to the ordinary sync master. A good value for RSSI is between -30 and -50
dBm.
A sync backup master base station will start to search for an active sync master within the
coverage for 1 minute. If a sync master is found during this first minute it will start up in
slave mode. In slave mode it will continuously search for the master base station and if the
master is not found it will enter the master mode. If no master is found during the first
minute of search it will immediately start up in master mode.
2007-06-18/ Ver. E
In this case the active sync bearer is only replaced if:
Alternative sync bearer with lower HOP value is found. Even if an alternative
bearer with better FER and RSSI is found this is only selected if the HOP value
is lower.
In this case the active sync bearer is only replaced if:
Another bearer with lower HOP value is found.
OR
Another bearer with same HOP value is found and with BER < 90.
Assume the slave has locked to a RFP with hop value n. When the RFP have
had FER = 100 on the active sync bearer for 80 seconds it is allowed to sync
to a RFP with hop value n+1. After another 40 seconds it is allowed to sync to
a RFP with hop value n+2, etc.
After 9 minutes with FER = 100 the "Sync lost counter" is increased and a
restart of the air sync procedure is done. ("Sync lost counter" may increase
for a number of other reasons also)
TD 92372GB
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