l1ctl_proto.h: extend ccch_mode enum with CBCH

According to GSM TS 05.02, there are two ways to enable CBCH:

  a) replace sub-slot number 2 of CCCH+SDCCH/4 (comb. V),
  b) replace sub-slot number 2 of SDCCH/8 (comb. VII).

Unlike SDCCH/8 (case b), CCCH+SDCCH/4 can be allocated on TS0
only, and shall not use frequency hopping. This means that
implementing CBCH support on SDCCH/8 would require much more
efforts than on combined CCCH+SDCCH/4, as in last case CBCH
messages can be received without the need to switch from
idle to dedicated mode.

This change introduces a new ccch_mode item, which should be
used by the higher layers to indicate presence of CBCH channel
on C0/TS0, so the PHY would enable decoding of CBCH messages
on CCCH+SDCCH/4 (case a) in idle mode.

Regarding to CBCH on SDCCH/8 (case b), it makes sense to
extend the 'l1ctl_dm_est_req', so it would be handled in
dedicated mode on request from the higher layers.

Change-Id: Ia94ebf22a2ec439dfe1f31d703b832ae57b48ef2

0 files changed, 0 insertions, 0 deletions