CELL RESELECT HYSTERESIS

• Level hysteresis for cell reselection applied when the new cells is in different location area.
• Alcatel default value 6dB; Value range 0dB to 14dB.
• Figure below is some example of border cells.  

 

 CELL RESELECTION

• If the mobile is moving in a border area between location areas, it might repeatedly change between location areas. Each change requires location updating and cause heavy signaling load and risk paging message being lost.  
• To prevent this, a cell reselect hysteresis parameter CRH is used. 
• The cell in a different location area will only be selected if the C1 of that cell is higher than the C1 of the current serving cell by the value of the Reselect Hysteresis. 

Since the Value of CRH maybe different for each cell, the CRH used for comparison will be the one broadcast by the serving cell. If the value is set very low then the mobile will Ping-Pong between location areas which will increase signaling load. If the value is set very high the mobile may camp in the wrong cell too long.