Slide 1

Inter layer HO threshold and inter layer HO hysteresis IntroductionIt can be seen in HO flow that ranking process comes first (after penalty processing) then different handovers are checked one by one.

Parameters Inter layer HO threshold & Inter layer HO Hysteresis performs four main functions in Huawei HO algorithm described in subsequent slides.

HO Flow

1-They are involved in 14th bit setting for both source & NBR which is the highest priority bit.

2-They are involved in NBR selection in case interference handover (third priority in emergency HO) is triggered

3-They are involved in NBR selection in case MS Fast Moving HO (second priority in Normal HO) is triggered

4-They are involved in NBR selection in case Layer/Level HO (third priority in Normal HO) is triggered

NOW if we take most common settings for Inter-Layer HO threshold (GCELLHOBASIC), Inter-layer HO Hysteresis (GCELLHOBASIC), Adjacent Cell Inter-layer HO Hysteresis (G2GNCELL), MS Fast Moving HO Allowed & Level HO Allowed for cells having LAYER OF THE CELL=3 in swapped networkInter-Layer HO threshold (GCELLHOBASIC)=5Inter-layer HO Hysteresis (GCELLHOBASIC)=2Adjacent Cell Inter-layer HO Hysteresis (G2GNCELL)=68MS Fast Moving HO Allowed=NOLevel HO Allowed=NO

First of all check for 14th bit:

For Source 14th bit to become 0(i.e. to make source prioritize)Rx lev (DL) source>= Inter-Layer HO threshold - Inter-layer HO Hysteresis i.e.

Rx lev (DL) source>= (5-2)-110Rx lev (DL) source>= -107db

For NBR 14th bit to become 0(i.e. to make NBR prioritize)Rx lev (DL) NBR>= Inter-Layer HO threshold + Adjacent Cell Inter-layer HO Hysteresis i.e.

Rx lev (DL) NBR>= (5+68-64)-110Rx lev (DL) NBR>= -101db

Now check for interference HO :

Source cell can be a candidate if Intra cell HO allowed=YES but we have put it off.

NBR is selected according to following criteria . Rx lev (DL) NBR>= Inter-Layer HO threshold + Adjacent Cell Inter-layer HO Hysteresis i.e.Rx lev (DL) NBR>= (5+68-64)-110Rx lev (DL) NBR>= -101db

SYNOPSISThat is we are making interference Handover to NBR cell having DL levels>= -101,so if HO failures are occurring & mainly due to Interference HO (while rest of Handovers are fine) we should modify either Inter-Layer HO threshold or Adjacent Cell Inter-layer HO Hysteresis.