So far we do all channel reassignments by Handover Command. Since
osmo-bsc now supports rassignment of ongoing voice calls, do intra-cell
congestion resolution by Assignment Command.
In effect, add support for expecting an Assignment Command in
handover_test, and expect assignments instead of handovers for
intra-cell congestion resolution test cases.
Related: SYS#5330 OS#3277
Change-Id: Id56a890106b93fcee67ac9401b890e7b63bba421
Fix flaws in picking a candidate for congestion resolution, shown in
recently added tests.
- For TCH/H->TCH/F upgrading, do not favor moving to a weaker neighbor
cell.
- When comparing dynamic timeslots on the same cell, favor a dynamic
timeslot that frees an entire dyn TS even though the target rxlev
differs.
Do not separate the passes for inter-cell and intra-cell candidates:
before, the inter-cell pass would already pick a candidate and start
handover, even though the subsequent intra-cell pass would have revealed
a better candidate. Join the intra-cell considerations into
pick_better_lchan_to_move().
The intra-cell pass was separate, because it would find the *weakest*
current rxlev, to give a TCH/H to TCH/F upgrade to the currently weakest
lchan.
Instead of the separate pass for weakest rxlev, in addition to the
target cell's rxlev, also consider the rxlev *change* in
pick_better_lchan_to_move(): For candidates that do not change the rxlev
(usually those that stay in the same cell) and that upgrade to TCH/F,
favor a candidate with weaker current rxlev.
Completely revisit the conditions in pick_better_lchan_to_move() to
yield the desired prioritization of candidate preferences.
In three handover tests, remove the "FAIL" comments and adjust to now
expect the actually desired behavior.
Related: SYS#5032
Change-Id: I2704899c85c35dfd4eba43468452483f40016ca2
Neels Hofmeyr