3.2 Dividing Clusters

3.2 Dividing Clusters

According to the features of UMTS technologies, the coverage and capacity are interactional and the frequency reuse factor is 1. Therefore RF optimization must be performed on a group of or a cluster of NodeBs at the same time instead of performing RF optimization on single site one by one. This ensures that interference from intra-frequency neighbor cells are considered during optimization. Analyze the impact of the adjustment of an index on other sites before adjustment.

Dividing clusters involves the following factors that must be considered:

• According to experiences, the number of NodeBs in a cluster depends on the actual situation. 10–13 NodeBs in a cluster is recommended. Too many or few NodeBs in a cluster is improper.
• A cluster must not cover different areas of test (planning) full coverage services.
• Refer to the divided clusters for network project maintenance of the operator.
• Landform factor

Landforms affect signal propagation. Mountains block signal propagation, so they are natural borders for dividing clusters. Rivers causes a longer propagation distance, so they affect dividing clusters in various aspects. If a river is narrow, the signals along two banks will interact. If the transportation between two banks allows, divide sites along the two banks in the same cluster. If a river is wide, the upstream and downstream will interact. In this situation, the transportation between two banks is inconvenient, dividing clusters by the bank according to actual situation.

• A cell-like cluster is much usual than a strip-like cluster.
• Administrative areas

When the coverage area involves several administrative areas, divide clusters according to administrative areas.

• DT workload

The DT must be performed within a day for a cluster. A DT takes about four hours.