Automatic Neighbor Relation (ANR) in LTE
Manually
adding neighbor cells in network is indeed a very hectic process in GSM & WCDMA Network. While networks are becoming more and more complex, it is
required to find an automatic and a more optimized way of adding neighbor
cells.
ANR comes under the umbrella of Self Organizing Networks ( SON) features. ANR relies on UE to detect unknown cells and report them to eNB. There are two major types:
i) UE based ANR
ii) ANR with OAM Support
ANR comes under the umbrella of Self Organizing Networks ( SON) features. ANR relies on UE to detect unknown cells and report them to eNB. There are two major types:
i) UE based ANR
ii) ANR with OAM Support
UE based ANR
·
No OAM support is
required.
·
UE detects PCI of
unknown cell when it needs to do measurement (as configured by network)
·
In case of
inter-frequency or inter-RAT measurements, eNB needs to configure measurement
gaps/or DRX so UE can detect PCI to different frequencies as well.
·
UE reports the unknown
PCI to eNB via RRC-Reconfiguration message.
·
eNB request UE to
report Eutran Cell Global ID (ECGI).
·
UE reports ECGI by
reading BCCH channel.
·
eNB retrieves the IP
address from MME to further setup the x2 interface.
ANR with OAM Support
·
OAM support is
required
·
Every new eNB
registers to OAM and download the table with information of PCI/ECGI/IP related
to neighbors
·
Neighbors also
update their own table with new eNB information
·
Now like "UE
based ANR", UE will detect unknown PCI and report it to the eNB
·
eNB doesn't request
for ECGI and does not need support from MME
·
eNB setups x2
interface with the help of mapping table created in second step above
