This chapter describes the
optimizations introduced in release 13 version of 3GPP specification to page
for the availability of UE by eNB. The paging enhancements are introduced to
support IoT requirements.
Feature Summary and
Product(s) or Functional Area
Changes in This Release
The feature is tested and qualified on the ASR 5500 platform.
encoding or decoding of these additional Information Elements (IEs) in S1AP
layer as part of paging optimizations introduced in Release 13 version of 3GPP
TS 36.413 standard.
The IEs supported for S1AP Paging are:
Capability for Paging: This IE contains paging specific UE Radio Capability
information. This IE is sent in UE-CAPABILITY-INFO-INDICATION message over
Information on Recommended
Cells and eNodeBs (eNBs) for Paging: This IE provides information on
recommended cells and eNBs for paging. This IE is included in
Identifier and Coverage Enhancement Level: This IE provides information for
paging CE capable UEs. This IE is included in UE-CONTEXT-RELEASE-COMPLETE
Assistance Data for
Paging: This IE provides assistance information for paging optimization.
This IE is sent in PAGING request message to page a UE in one or several
The eNodeB sends
paging assistance IEs as part of UE Context Release procedure. MME stores these
decoded IEs and sends back this information during paging procedure to eNB in
order for the EPC and the E-UTRAN to optimize usage of network resources.
The MME supports UE
Radio Capability for Paging Information as per TS 23.401 standard. This is
required for Cat-0/Cat-M1/NB-IoT devices to provide extended coverage.
This feature is license controlled. Contact your Cisco account
representative for information on how to obtain a license.
How it Works
paging procedure to page a UE by sending PAGING message to the eNB. MME
includes "UE Radio Capability for Paging" and "Assistance Data for Paging" IEs
if available for the UE. If the "UE Radio Capability for Paging" IE is included
in the PAGING message, the eNB uses it to apply specific paging schemes. If the
"Assistance Data for Recommended Cells" and "Assistance Data for CE Capable
UEs" IEs are included in the Assistance Data for Paging IE, it is used along
with the Paging Attempt Information IE if present. If the "Next Paging Area
Scope" information is included in the Paging Attempt Information IE, it is used
for paging the UE.
The eNB controlling
a UE-associated logical S1 connection initiates the procedure by sending a
UE-CAPABILITY-INFO-INDICATION message to the MME. This message includes UE
Radio Capability for Paging IE containing paging specific UE capability
information. This information replaces any previously stored information in the
MME for the UE. This information is transparent to MME, which stores the
received information as is and sends back the same to eNB in S1-Paging message.
operation of MME initiated UE-CONTEXT-RELEASE, the eNB, if supported, reports
the following information "Information on Recommended Cells and eNBs for
Paging" IE & "Cell Identifier and Coverage Enhancement Level" IE in
UE-CONTEXT-RELEASE-COMPLETE message. The MME stores this information and sends
back the same in subsequent Paging message initiated from MME. This information
replaces any previously stored information in the MME for the UE. This
information is transparent to MME, which stores the received information as is
and sends back the same to eNB.
During Attach without PDN / Attach with CP Optimization enabled / TAU
Attach with Attach without PDN enabled cases, MME sends the Connection
Establishment Indication message without UE Radio Capability IE to eNB if it
does not have the information after Attach Accept/TAU Accept. If eNB receives
this message without UE Radio Capability IE, it fetches the data and sends it
in the UE-CAPABILITY-INFO-INDICATION message.
The following are the list of
limitations with respect to the configuration of this feature:
MME does not store the "UE
Radio Capability for Paging" IE with a length exceeding 1024 bytes. This IE
information is stored only when the maximum length of the IE is within 1024
MME recovers the stored "UE Radio Capability for Paging"
information as part of session recovery, but does not recover the following
information "Information on Recommended Cells and eNBs for Paging" and "Cell
Identifier and Coverage Enhancement Level".
Monitoring and Troubleshooting the Paging Enhancements
This feature does not have any functional impact in the field if MME
fails to decode the new S1AP IE(s);
It continues to process the "UE-CONTEXT-RELEASE-COMPLETE" and
release the resources if any exists for the S1 connection.
It continues to send the S1-Paging as it is sending currently
without the optional parameters.
If the feature is not working as expected, the following information
needs to be collected to help debug the issue further:
show mme-service session full imsi
<imsi> command will help to
identify if MME is able to decode and store the "UE Radio Capability for
Paging" IE as part of UE context.
monitor subscriber … or
monitor protocol command along with S1-AP
protocol enabled for the affected subscriber where the dissected protocol
information is available for all S1AP messages with the new IE(s).
MME does not store the received UE Radio Capability for Paging
information if it exceeds the maximum allowed limit and it prints the following
log, "2016-Aug-18+05:40:14.307 [mme-app 147072 debug] [2/0/14972
<sessmgr:1> access_s1.c:1461] [software internal user syslog] Error
processing NAS msg. Length of UE Radio Capability for Paging IE is more than
Show Command(s) and/or Outputs
This section provides information regarding show commands and/or their
outputs in support of this feature.
The show commands in this section are available in support of the
Paging Enhancement feature.
A new bulk statistic "s1ap-transdata-connestind" is added in this schema to count the total number of times MME has sent Connection Establishment Indication message over S1AP interface to eNodeB.
session full imsi
A new field "Radio
Capability for Paging" has been added to the output of this show command. This
field displays the value in hexadecimal format if the UE received "UE Radio
Capability for Paging" IE in S1 "UE-CAPABILITY-INFO-INDICATION" message from
eNB. Otherwise, this field displays N/A.
show mme-service statistics
A new field "Connection Est Ind" is added to this command under Transmitted S1AP Statistics to display the total number of times MME has sent Connection Establishment Indication message over S1AP interface to eNodeB.
This command is used for monitoring and troubleshooting a particular
UE. When S1-AP protocol is enabled for the UE, this command displays the
dissected protocol information for the associated IE(s).