Will inner band retain the call if outer band signals are weak?
Consider the following scenario:
We have 900 outer and 1800 inner band serving on a cell. BCCH / SDCCH is on 900 and 1800 only caters TCH.
Suppose tilts are such that 1800 serves a radius of 5 kilometers while 900 serves a radius of 3 kilometers only (undesirable but can happen).
Now suppose the call gets established when caller is within 2 kilometer of serving cell (on 900 of course) and then call is handed over to 1800. Customer is moving and exceeds the distance of 3 kilometers (serving area of 900 band is exceeded). Will the call retain on 1800 or does it need the BCCH of serving site to be strong enough to continue the call?
If the call was already going on in the inner zone and the HO to outer zone is not detected, then the call will still go on, even without BCCH.
MS is not listening to the serving BCCH.
However, Prof, this network topology is very risky. It would be smarter to define your outer zone = 1800 and inner zone = 900. That would let you use the HO algorithms properly. Because in your situation, the in>out and out>in HO algo are certainly tuned in a very weird way 🙂