- This topic has 10 replies, 1 voice, and was last updated 14 years, 5 months ago by SHELDON.
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7th August 2010 at 16:14 #63975manishGuest
HI all,
i have one confusion abt intra bsc and inter bsc handover
if i have MSC A AND BSC A,BSC B ARE UNDER THIS MSC A
AND MSC B AND BSC 1 ,BSC 2 ARE UNDER THIS
THEN FROM BSC A TO BSC 1 HANDOVER CALLED INTER BSC HANDOVER?
AND BSC A TO BSC B HANOBER CALLED INTER OR INTRA BSC HANDOVER?
AND GUYS ONE MORE CONFUSION WHICH ARE INTERNAL AND EXTERNAL HANDOVER?
12th August 2010 at 07:17 #63976manishGuestPlz help …….
12th August 2010 at 10:31 #63977SHELDONGuestHi Manish,
Inter-BSC handover: handover between cells on different BSCs.
Intra-BSC handover: handover between cells on the same BSC.
Both cases you described are inter-BSC handovers. However, the first case is also an inter-MSC handover.
I’m not sure what you mean by internal handover…maybe it’s your vendor’s vocabulary. However, I think an internal handover will be the same as an intra-BSC handover, and an external handover an inter-BSC handover.
Regards,
SHELDON14th August 2010 at 10:49 #63978manishGuestHi sheldon,
thanks buddy now cleared the doubt .but next question is that we have inter bsc handover problem so by tunning t3121 from 20 to 25 sec will help or its good to stick with 20 sec value?
and other timer like t3103,t7,t8 will help and how this timer works plz tell waiting……
17th August 2010 at 12:06 #63979manishGuestHi,
sheldon plz help..
17th August 2010 at 18:51 #63980pixGuestmanish,
what do you mean by “inter bsc ho problems” ?can you share your HO KPIs ?
preparation success rate
efficiency rate
# of requests, allocations and success (in both directions)regards
pix
18th August 2010 at 16:11 #63981manishGuestHi pix,
buddy i have inter bsc problem everywhere where the boundrays of bsc are coming and ITS LIKE bsc A WITH ITS CELL 1
AND BSC B WITH ITS CELL 4 SO HANDOVER FROM CELL 1 TO CELL 4 AND CELL 4 TO CELL 1 WHICH ARE INTER BSC HANDOVER IN THAT HO SUCESS RATIO IS POORITS LIKE HANDOVER FROM CELL 1 TO CELL 4 ARE 100 AND OUT OF THAT SUCCESS ARE ONLY 50 TO 60.
AND THIS SCENARIO IS EVERYWHERE IN BY INTER BSC CELLS HANDOVER.
SO I PUT THIS Hi sheldon,
thanks buddy now cleared the doubt .but next question is that we have inter bsc handover problem so by tunning t3121 from 20 to 25 sec will help or its good to stick with 20 sec value?
and other timer like t3103,t7,t8 will help and how this timer works plz tell waiting……
SO PLZ HELP IF THIS TIMER WILL HELP OR NOT AND IF ANY OTHER SOLUTION PLZ SUGGEST?
19th August 2010 at 05:09 #63982jackGuesti have one doub about inter bsc (external handover)
BSC s are NOKIA and MSC s are Ericson.
after that BSC recognise that an External handover is required BSC send a HANDOVER_REQUIRED msg to MSC(ericsson) and After receiving a HANDOVER_REQUIRED message from the BSC, the MSC determines the candidate cell(?) and sends a HANDOVER_REQUEST message to the target BSC. When the BSC receives this message, the handover attempt is started. The message contains, for example, information on the cell identifier of the candidate cell.my doubt is on ? in my previous statement.
How does MSC recocnise exactly the BSC of target cell??
is it true?
MSC only Know LAC of one cell and know that this LAC belong to which BSC?
how about this position if one LAC consist of several BSC?
how does MSC recognise to witch BSC the cell belngs??19th August 2010 at 05:13 #63983jackGuesthow does MSC specify the target cell from the list of candidate cell that BSC send to it?
is rxlev is important?
i mean that the cell with highest rxlev is picked???19th August 2010 at 07:08 #63984pixGuestjack,
the serving BSC sends a list that contains only N_PREF_CELLS (usually 3, or 1). This list is ordered accordingly to the BSC candidate evaluation algo. The MSC selects the 1st cell.
regarding the LAC vs BSC :
I don’t have the explanation, but i just know the MSC knows where each cell is located 🙂 In the MSC, there is a table that links LAC with BSC, and probably other tables that links the cell with the BSC.regards
pix19th August 2010 at 13:33 #63985SHELDONGuestHi Manish,
Sorry for my late reply.
From what I found out, T3121 only applies to 2G to 3G handovers, so I don’t think tuning it will improve your handover success rate in any way. In any case, 20s is long enough for a handover to take place.
T3103 is used to reserve the old channel so that in case the activation of the new channel fails, the call can return to the old channel. Thus, tuning it will also not improve handover success rate.
T8 applies in inter-BSC handover and T7 in inter-MSC handover. Unless your problem is related to these, you should not touch these timers.
From my experience, the majority of handover failures occur as a result of interference, hardware faults or poor synchronization. If your target cell is congested, you can also have handover failures. I think you should focus on these, rather than the timers.
Regards,
SHELDON -
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