While there are challenges associated with building any new wireless network, one of these challenges is managing neighbor cells. This is a tough task even for traditional mobile networks, and it becomes even harder as new mobile technologies roll out with 2G and 3G cells already exist. These neighbor cells are firmly in place and not going anywhere.
To help address this, and to stay in line with 3GPP specifications, network operators are turning to Automatic Neighbour Relation (ANR) functionality and PCI plannig. ANR relieves the burden of manually managing Neighbor Relations (NR) and ANR function lives in the eNB and manages the Neighbour Relation Table (NRT). Within this table are many facets and branches that help deal with these neighbor cells.
When it comes to LTE PCI. Harish Vadada (http://www.telecom-cloud.net/wp-content/uploads/2010/09/PCI-Planning-for-LTE.pdf ) lists two main strategy options in his white paper LTE PCI Planning. The first strategy involves grouping neighboring sites into clusters and then assigning those clusters a code group. Each site is assigned a specific code group and each sector a specific color group. The second strategy is random planning, meaning that the PCI plan doesn’t consider PCI grouping and does not follow a specific or tailored reuse pattern.
When planning PCI, Vadada recommends the following tips:
1) The same PCIs should be avoided within the same site and as neighbors
2) PCIs with conflicting k values should be avoided within the same site and as neighbors
3) PCIs with conflicting m0 and m1 values should be avoided within the same site and as neighbors
PCI Pollution: There is no definite answer for this however in simple terms any of the neighboring PCI is considered as pollution if it is undesirable i.e. mis configuration, bad planning etc...
Sorry for being too descriptive?
