hi Shan and Tomar,
Thanks tomar for your valuable inputs, it’s very interesting 🙂
Shan :
HO MARGIN is the margin used for the power budget handover :
cell 1 = serving cell
cell 2 = neighbour cell
if the difference of rxlev between cell1 and cell2 is greater than HO MARGIN (cell1, cell2) –> MS will handover from cell 1 to cell 2
To prevent the MS to go back to cell 1, you have to adapt the margin “HO MARGIN (cell 2, cell 1)”, in order to always verify the rule :
HO MARGIN (cell 1, cell2) + HO MARGIN (cell 2, cell 1) = 10 dB
Tomar:
yes, of course, the idle mode behaviour should be modified, otherwise HO will be triggered right after the call setup. The Cell Reselect Offsets should be equal to:
CRO(cell 1) = (HOMARGIN(cell 1,cell 2) / 2) + (HOMARGIN(cell 2,cell 1) / 2) = 10/2 + 0/2 = 5 dB
CRO(cell 2) = 0 dB
(this formula gives a CRO that makes the MS in idle mode to camp in the middle of a zone where there won’t be a PBGT HO right after the call)
it reminds me : I used to work with negative HO MARGIN (homargin(1,2) = +15dB and homargin(2,1) = -5dB), in case of GSM900 cells and DCS1800 cells + activation of PBGT handovers…