Manual

In case of network sharing, single radio network will be shared by more than one network operator. This
information about availability of multiple operators needs to be propagated to MS so that it can select correct
(home or equivalent) network out of all available networks.
To advertise availability of multiple core network operators on a single radio network, broadcast information
has been modified to contain a list of PLMN-Ids representing core network operators sharing the particular
radio network. The traditional PLMN-Id broadcasted by radio network before network sharing support was
available is now called as "common PLMN Id".
MS not supporting network sharing feature would see only "common PLMN Id", while MS supporting network
sharing feature would be able to see the list of PLMN-Ids along with "common PLMN Id".
Supporting MS would be responsible for selecting appropriate core network, while RNC and MSC/SGSN
will help select appropriate core network for non-supporting MS through redirection procedure.
Redirection for non-supported UEs
Selection of the operator for non-supporting UE is the responsibility of HNBGW. HNBGW sets redirect
attempt flag in Initial UE Message and randomly/intelligently forwards the request to the CN node of the
operator. Operator CN Node based on redirection attempt flag knows that redirection to different operator is
possible for this node. If the current operator is ready to accept the call it will send redirection complete in
direct transfer message. HNBGW based on the redirection complete IE knows that redirection procedure is
successful. If operator is not ready to accept the call or it thinks that CS/PS co-ordination is required then it
sends redirection indication to HNBGW. HNBGW then sends the Initial UE message randomly/intelligently
to another operator.
CS/PS Domain Coordination
When a CN node receives a registration from a subscriber with a non-supporting UE having a P-TMSI/TMSI
not belonging to the pool, and no IMSI is provided by RNC, it returns a Reroute Command message to the
RNC with an indication that it is for coordination purposes. The coordination may result in that the registration
is sent back to the same CN node or CN operator again.
As HNBGW will not look into MM/GMM messages, it will apply coordination for all RUA Connect/Initial
UE Messages for non-supported UEs. For supported UEs CS/PS coordination is the responsibility of the UEs.
HNBGW does not consider whether GS interface is present between SGSN and MSC. Because if GS interface
is present UE may does combined CS/PS Attach, which inherently will take care of CS/PS coordination. If
IMSI is available at HNBGW it sends it in Initial UE Message.
A request from any domain is processed first to select the operator. Once the operator is selected same is
stored in UE context. If UE Context is active and request from another domain is received then this request
is forwarded to the same operator. In case a request from one domain is in progress and same time request
from another domain is received for same UE, then the later request is kept on hold till the first request is
complete.
NAS Sequence number for CS-domain
When the redirection takes place for non-supported UEs, the CN node of the redirecting CN operator shall
forward via the RAN the value of N(SD) of the last message received on the MM+CC+SS (via CS
domain)message flow to the CN node of the next CN operator. By counting uplink direct transfer messages
HNBGW will keep track of NAS sequence numbering. It will ignore NAS sequence number received in
redirection indication to another CN operator.
HNB-GW Administration Guide, StarOS Release 19
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HNB Gateway in Wireless Network
Multi-Operator Core Network (MOCN)