Outgoing Inter-RAT Inter-Cell Handover Measurement per Cell

Description

The Outgoing Inter-RAT Inter-Cell Handover Measurement per Cell can be classified into Outgoing Inter-RAT Inter-Cell Handover Requests (Excluding Directed Retry) and Outgoing Inter-RAT Inter-Cell Handover Requests (Directed Retry).

• Outgoing Inter-RAT Inter-Cell Handover Requests (Excluding Directed Retry)

  BSC2 (where the originating cell is) receives the MR from the MS, and performs handover algorithm based on the traffic load and interference level of the serving cell, and the signal quality and transmit/receive level reported in the MR. If the handover algorithm decides to trigger the handover, BSC2 sends a handover triggering command to the service process handling module to initiate the handover procedure. If the target cell of the handover is a cell belonging to another system, the inter-RAT handover is triggered. The outgoing inter-RAT inter-cell handover performance is measured in the source cell.

  BSC2 sends HQ RQD to MSC2, requesting the MSC2 to inform another system of an inter-RAT handover. Based on its data configuration, MSC2 finds out the corresponding MSC of the other system, that is, MSC1, and sends a handover request to MSC1. When the other system is ready for the handover, it informs MSC2. Then MSC2 sends an HO CMD message to BSC2 to inform the MS of handover initiation. BSC2 sends HO CMD to the MS in the source cell, requesting the MS to access the target cell. When the MS accesses to the target cell successfully, MSC1 notifies MSC2 of the completion of incoming inter-RAT inter-cell handover. Then MSC2 sends CLR CMD to BSC2. When the source cell resource has been released, BSC2 replies a CLR CMP message to MSC2. Thus, the outgoing inter-RAT inter-cell handover is complete..

  Figure 1 Outgoing inter-RAT inter-cell handover requests procedure (excluding directed retry)
  
  

  A: Request for an outgoing inter-RAT inter-cell handover

  B: Command for an incoming inter-RAT inter-cell handover

• Outgoing Inter-RAT Inter-cell Handover (Directed Retry)

  The MS starts the call. After receiving an ASSIGN REQ message from MSC2, BSC2 decides the assignment mode based on the load of the cell. There are three assignment procedures: normal assignment procedure, directed retry procedure, and mode modification procedure. If the load of the cell is so high that the cell cannot admit a new service or that a new admitted service will affect the current services, BSC2 decides to perform a directed retry. If the target cell selected during the directed retry belongs to another system, BSC 2 initiates an outgoing inter-RAT inter-cell handover procedure in the source cell. For the originating cell, an outgoing inter-RAT inter-cell handover is initiated.

  After that, BSC2 sends HQ RQD to MSC2, requesting MSC2 to notify the other system of initiating the handover. Based on its data configuration, MSC2 finds out the corresponding of the other system, that is, MSC1, and sends a handover request to MSC1. When the other system is ready for the handover, it informs MSC2. Then MSC2 sends an HO CMD message to BSC2 to notify the MS of initiating the handover. BSC2 sends HO CMD to the MS in the source cell, requesting the MS to access the target cell. When the MS gets normal access to the target cell, MSC1 notifies MSC2 of the completion of incoming inter-RAT inter-cell handover. Then MSC2 sends CLR CMD to BSC2. When the source cell resource has been released, BSC2 replies a CLR CMP message to MSC2. Thus, the outgoing inter-RAT inter-cell handover in the directed retry procedure is complete.

  Figure 2 Outgoing inter-RAT inter-cell handover requests procedure (directed retry)
  
  

  A: Request for an outgoing inter-RAT inter-cell handover

  B: Command for an incoming inter-RAT inter-cell handover

Measurement Object

Cells.

Measurement Counter

The following table lists the measurement counters related to Outgoing Inter-RAT Inter-Cell Handover Measurement per Cell.