gsm_04_08_rr: fix hopping parameters in RR Assignment Command

According to 3GPP TS 44.018, section 9.1.2.4, if at least one of
the Channel Description IEs indicates frequency hopping, one and
only one of the following IEs shall be present:

  - Mobile Allocation, after time (see 10.5.2.21);
  - Frequency List, after time (see 10.5.2.13).

For some reason, osmo-bsc includes the GSM48_IE_MA_BEFORE instead
of GSM48_IE_MA_AFTER - fix this.

According to section 9.1.2.6 of the same document, if any of the
Mobile Allocation IEs (before/after time) is present, then the
network must ensure that either the MS has already received the
the proper reference cell frequency list (CA), or that the Cell
Channel Description IE (see 10.5.2.1b) is present.

Without this IE, the phone I was using in my testing setup sends
RR Status message with cause #100 "conditional IE error".

Fortunately, we already have generate_cell_chan_list(), since we
also need to include the Cell Channel Description in SI Type 1.

Change-Id: I43ef66c109b107ebcaa1cb6197637701b13b3787
Related: SYS#4868, OS#4545, OS#4546

0 files changed, 0 insertions, 0 deletions