When a VGCS/VBS call is established in a cell, NCH is used to notify
about ongoing calls to idle subscribers. Additionally Notification/FACCH
is used to notify subscribers in dedicated mode. This is performed by
broadcasting this messages to all active dedicated channels. The mobile
station can then indicate the call, so the user can join the call.
More importaint is the notification of the calling subscriber's MS,
which initiated the call. This is done on the early assigned channel.
The MS must know on which channel the call is placed. After leaving the
uplink, it must know where to access the uplink the next time.
Change-Id: I3ed14fa54a907891e492a7ada8e745a2c56cd46d
Related: OS#4851, OS#5781
The location of the NCH is defined by the rest octet of System
Information 1. If NCH is defined, the given CCCH blocks are used for NCH
instead of AGCH/PCH.
The current list of VGCS/VBS call notifications is transmitted on the
NCH. If there is no notification, an empty notification is transmitted
on the NCH.
The Notification List Number (NLN) is used to indicated new
notificaitons. Only the last notification (or empty notification)
indicates NLN. This way the MS can determine after two equal NLN that
the complete list has been recevied.
Change-Id: I82fdaba3faaced76267a99ae14a5458a1b41fdaa
Related: OS#5781
This adds very minimalistic support for notification of VBS/VGCS calls.
Minimalistic in that we
* only notify via PCH (not via NCH or FACCH)
* only include notification in otherwise empty PAGING TYPE 1
This means that notification will cease to work once the PCH becomes too
loaded and we never would send otherwise empty PAGING TYPE 1 anymore.
Change-Id: I6f6f72d9a0123cb519b341d72a124aaa2117370e
Requires: libosmocore.git I9586b5cb8514010d9358fcfc97c3d34741294522
Related: OS#5781
Andreas Eversberg
Harald Welte