Handover
Hanover is the process in which a cellular phone is handed from one cell to the next in order to maintain a radio connection with the network.
There are about 31 handover causes and they can be mainly categorized into two groups. Followings are mostly considered.
| Emergency | Better Condition | ||
| Cause 2 | Too low quality on uplink | Cause 12 | Power budget evaluation |
| Cause 3 | Too low level on uplink | Cause 20 | Forced directed retry |
| Cause 4 | Too low quality on downlink | Cause 23 | Traffic |
| Cause 5 | Too low level on downlink | Cause 24 | General capture |
| Cause 6 | Too long distance between MS & BTS | Cause 27 | AMR channel adaptation (FR to HR) |
| Cause 15 | High interference on uplink (Intracell HO) | Cause 28 | Fast traffic HO |
| Cause 16 | High interference on downlink (Intracell HO) | Cause 29 | Tandem free HO |
| Cause 26 | AMR channel adoption HO | Cause 30 | Move from PS to CS zone |
Other handover causes
Cause 07: Consecutive bad SACCH frames received in a microcell
Cause 10: Too low level on the uplink in the inner zone
Cause 11: Too low level on the downlink in the inner zone
Cause 13: Outer zone level on uplink and downlink
Cause 14: High level in neighbor lower large cell for slow mobile
Cause 17: Too low level on the uplink in a microcell compared to a high threshold
Cause 18: Too low level on the downlink in a microcell compared to a high threshold
Cause 21: High level in neighbor cell in the preferred band
Cause 22: Too short MS – BTS
Cause 31: 2G to 3G handover