Function Change
or may not, have a direct signalling link to
the BSC.
RU
The smallest unit that can be handled on
site or in a repair center. Information
about the RU can be retrieved via OMT or
BSC.
Software file
The software necessary for a class of Main
RU. A software file contains application
software.
22.2
Functions
RBS
SW file
01_0285A
Distributed
main RU
Central
main RU
File
package
A-bis
Figure 37
Overview of function change
22.2.1
Software Storage
Every Main RU is equipped with both volatile and non-volatile memory.
Application software, either downloaded via the A-bis interface,
transferred internally, or installed during manufacture, is stored
semi-permanently in the non-volatile memory.
Before execution, the software is copied from the non-volatile memory
into the volatile memory, where it is executed. This arrangement permits
the RBS to operate normally, i.e. executing one version of software
while loading a new version of software as a background activity.
One area of the non-volatile memory contains the base application
software. The base application software can only be updated by
function change if the normal application software is valid, thus there is
always one application software available. If the normal application is
corrupt (or unavailable), the base application software is automatically
selected instead.
22.2.2
Software File Relation
Each Main RU visible via the A-bis interface is offered every software
file within the appropriate file package. The file revision of the offered
software file is compared with that of the software files already held in
non-volatile memory in order to determine whether download is
necessary or not. Download is carried out only when the file offered
has a different revision than the one held in RBS memory.
144 (306)
EN/LZT 123 2697
R5A
1998-08-13
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— All Rights Reserved —
