handover decision 2: load balancing across BSS
I have today implemented a first rudimentary decision tradeoff for inter-BSC HO: never do load balancing across BSS boundaries,
because that is asking for oscillation. So we do inter-BSC handover like in the handover decision algorithm 1:
only if the current lchan drops below the minimum required rxlev / max ta, and a remote-BSS has better rxlev.
(So far this is on branch osmo-bsc:neels/ho2-interbsc, needs some polishing and merge.)
In the long run, there are options for load balancing across BSS:
- trigger inter-BSC HO, and the remote-BSS refuses to accept it if it feels too loaded.
The handover algorithm penalty timers will then prevent asking the same remote-BSS too often.
- the "Old BSS to New BSS Information" IE in the BSSMAP Handover Required:
we can send some load indication along, and the target BSS could accept only if it is less loaded.