raghdu, the paging success rate is a bit tricky… in my experience, the only paging failure might be caused by congestion in the paging channels of the cells or congestion in the BSC itself.
In Alcatel system, we do not count those failures, so we don’t have a paging failure rate (or a paging success rate), but rather a PAGING LOAD (amount of paging performed during one hour / capacity of the PCH channels).
I personally don’t think it is possible to compute a paging success rate, unless you know about the PCH congestion in each cell. Does your system provide this information ?
You can work with the PAGING LOAD though : you just have to set a paging load threshold (let’s say 10%) and if the paging load is greater than 10% it means you’re in overload 😉