LOCATION UPDATE OPTIONS
In order to ensure the correct routing of an incoming call to a MS, the network needs to know
the current location of that MS down to cell level. This can be achieved by one of three
methods:
· Location Update on Every Cell Change
Every time an MS moves into a different cell area, it sends a location update to the
network. This has the advantage that no paging is required to establish the cell
location of an MS for each incoming call. However, it imposes a significant load on
the network signalling channels.
· Paging All Cells
Every time an incoming call is to be routed to an MS, all cells in the network are
paged to identify the cell owning the MS. This has the advantage that no location
updating is required to maintain a current MS location log. However, it imposes a
significant load on the network signalling channels.
the current location of that MS down to cell level. This can be achieved by one of three
methods:
· Location Update on Every Cell Change
Every time an MS moves into a different cell area, it sends a location update to the
network. This has the advantage that no paging is required to establish the cell
location of an MS for each incoming call. However, it imposes a significant load on
the network signalling channels.
· Paging All Cells
Every time an incoming call is to be routed to an MS, all cells in the network are
paged to identify the cell owning the MS. This has the advantage that no location
updating is required to maintain a current MS location log. However, it imposes a
significant load on the network signalling channels.
Location Update Options
• Send location update on every cell change
• No paging requirement
• Excessive signalling traffic load
• Page every cell in network
• No location update requirement
• Excessive signalling traffic load
• Subdivide network into paging areas
• Requires paging procedure with reduced traffic load
• Required location updating with reduced traffic load
• No paging requirement
• Excessive signalling traffic load
• Page every cell in network
• No location update requirement
• Excessive signalling traffic load
• Subdivide network into paging areas
• Requires paging procedure with reduced traffic load
• Required location updating with reduced traffic load
Subdivide Network into Paging Sub-Regions
Every time an MS moves in a new paging sub-region it informs the network of that
sub-region identity. Every time an incoming call is to be routed to an MS, only the
cells in its current paging sub-region are checked. This provides a comprise between
the two above options and has been proved to reduce signalling channel loads
significantly.
Every time an MS moves in a new paging sub-region it informs the network of that
sub-region identity. Every time an incoming call is to be routed to an MS, only the
cells in its current paging sub-region are checked. This provides a comprise between
the two above options and has been proved to reduce signalling channel loads
significantly.
-GSM LOCATION AREAS (LAs)
Within GSM networks these paging sub-regions are known as a Location Areas (LAs) and
comprise a number of cells. All cells within the LA must be under the control of a single MSC
and within the same PLMN. Each LA within the PLMN is uniquely identified by a Location
Area Identifier (LAI).
comprise a number of cells. All cells within the LA must be under the control of a single MSC
and within the same PLMN. Each LA within the PLMN is uniquely identified by a Location
Area Identifier (LAI).
-CONDITIONS FOR LOCATION UPDATES
Location Updates occur under one of the following conditions:
· On change of LA
· Periodic Updates
· On MS switch on (IMSI attach)
· When changing cells during a call
· On change of LA
· Periodic Updates
· On MS switch on (IMSI attach)
· When changing cells during a call
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