Happy New Year 2012 !!!
My question is about gsm900 and umts900 interworking….
After activation of umts900 on sites with gsm900 we faced that there is increase of UL/DL interferences in gsm cells. What can be the problem, TMA, couplers or something else?
The other case is that, after this activation there is problem with 3G to 2G handovers. There are attempts for this handovers, but all of them are unsuccesfull? The configuration parameters in 2G and 3G looks OK…
Please give us idea, what can be the problem…
for interference : are you certain the UMTS bandwidth is not overlapping with your GSM carriers ?
Are all GSM frequencies interfered ? (i don’t think so)
How are you connecting the BTS and the antennas ? Are you duplexing/combining 2G and 3G onto the same feeders ?
regarding the 3G/2G HO, you need to analyze the problem:
– is the HO detected ? (see the 3G qos stats)
– does the RNC send the HO REQ to the BSC ?
– does the BSC receives it ?
you have to know at what stage the failure is occuring.