U.S. patent application number 13/398763 was filed with the patent office on 2013-08-22 for system and method for enhanced paging and quality of service establishment in mobile satellite systems.
The applicant listed for this patent is Channasandra Ravishankar, Gaguk Zakaria. Invention is credited to Channasandra Ravishankar, Gaguk Zakaria.
Application Number | 20130217422 13/398763 |
Document ID | / |
Family ID | 48982661 |
Filed Date | 2013-08-22 |
United States Patent
Application |
20130217422 |
Kind Code |
A1 |
Zakaria; Gaguk ; et
al. |
August 22, 2013 |
SYSTEM AND METHOD FOR ENHANCED PAGING AND QUALITY OF SERVICE
ESTABLISHMENT IN MOBILE SATELLITE SYSTEMS
Abstract
A system and method is provided to enable enhanced paging for
3GPP IMS based Mobile Satellite Communication is presented. The
method is achieved by utilizing the network requested secondary PDP
context activation (NRSPCA) features of 3GPP release 7. NRSPCA
involves interaction between P-CSCF, GGSN, and SGSN that eventually
allows SGSN to identify the traffic type of the incoming call
without looking at the compressed SIP messages. RAN can do enhanced
paging, if necessary; based on the request secondary PDP context
activation message, if the Paging Cause is indicating
conversational class. In another embodiment, enhanced paging can be
achieved by marking the packet with an appropriate DSCP code, which
is done by the P-CSCF. SGSN can populate the paging cause with
enhanced paging code based on the DSCP code provided or RAN can
escalate paging to enhanced paging by examining the DSCP code.
Inventors: |
Zakaria; Gaguk; (College
Park, MD) ; Ravishankar; Channasandra; (Clarksburg,
MD) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Zakaria; Gaguk
Ravishankar; Channasandra |
College Park
Clarksburg |
MD
MD |
US
US |
|
|
Family ID: |
48982661 |
Appl. No.: |
13/398763 |
Filed: |
February 16, 2012 |
Current U.S.
Class: |
455/458 |
Current CPC
Class: |
H04B 7/18539 20130101;
H04B 7/18567 20130101; H04W 76/12 20180201; H04B 7/18543 20130101;
H04W 68/025 20130101 |
Class at
Publication: |
455/458 |
International
Class: |
H04W 68/00 20090101
H04W068/00 |
Claims
1. A system for use with an input signal, a satellite and a user
terminal, the input signal corresponding to one of a first type of
data and a second type of data, the satellite being in
communication with said system and the user terminal, said system
comprising: a communication portion operable to receive the input
signal; a determining portion operable to determine whether the
input signal corresponds to the first type of data or the second
type of data; and a paging portion operable to generate a first
paging signal and a second paging signal, the first paging signal
having a first amplitude and a first waveform, the second paging
signal having a second paging signal and a second waveform, wherein
said communication portion is further operable to transmit to the
user terminal, via the satellite, the first paging signal based on
said determining portion determining that the input signal
corresponds to the first type of data, wherein said communication
portion is further operable to transmit to the user terminal, via
the satellite, the second paging signal based on said determining
portion determining that the input signal corresponds to the second
type of data, and wherein one of the first amplitude is less than
the second amplitude and the first waveform is different than the
second waveform.
2. The system of claim 1, wherein said communication portion and
said paging portion comprise a radio access network.
3. The system of claim 1, wherein said communication portion is
further operable to transmit to the user terminal, via the
satellite, the first paging signal for a predetermined period of
time before transmitting the second paging signal.
4. The system of claim 1, wherein said communication portion is
operable to transmit the first paging signal and the second paging
signal using a signaling protocol.
5. A method of using an input signal, a satellite and a user
terminal, the input signal corresponding to one of a first type of
data and a second type of data, the satellite being in
communication with said device and the user terminal, said method
comprising: receiving the input signal; determining whether the
input data corresponds to the first type of data or the second type
of data; generating one of a first paging signal when the input
data corresponds to the first type of data and a second paging
signal when the input data corresponds to the second type of data,
the first paging signal having a first amplitude and a first
waveform, the second paging signal having a second paging signal
and a second waveform; and transmitting to the user terminal, via
the satellite, the generated one of the first paging signal and the
second paging signal, wherein one of the first amplitude is less
than the second amplitude and the first waveform is different than
the second waveform.
6. The method of claim 5, wherein said receiving the input signal
comprises receiving the input signal via a radio access network,
and wherein said transmitting to the user terminal, via the
satellite, the generated one of the first paging signal and the
second paging signal comprises transmitting to the user terminal,
via the satellite, the generated one of the first paging signal and
the second paging signal from the radio access network.
7. The method of claim 5, further comprising transmitting to the
user terminal, via the satellite, the first paging signal for a
predetermined period of time before transmitting the second paging
signal.
8. The method of claim 5, wherein said transmitting to the user
terminal, via the satellite, the generated one of the first paging
signal and the second paging signal comprises transmitting to the
user terminal, via the satellite, the generated one of the first
paging signal and the second paging signal using a signaling
protocol.
9. A tangible, non-transitory, computer-readable media having
computer-readable instructions stored thereon, the
computer-readable instructions being capable of being read by a
computer to use an input signal, a satellite and a user terminal,
the input signal corresponding to one of a first type of data and a
second type of data, the satellite being in communication with said
device and the user terminal, the computer-readable instructions
being capable of instructing the computer to perform the method
comprising: receiving the input signal; determining whether the
input data corresponds to the first type of data or the second type
of data; generating one of a first paging signal when the input
data corresponds to the first type of data and a second paging
signal when the input data corresponds to the second type of data,
the first paging signal having a first amplitude and a first
waveform, the second paging signal having a second paging signal
and a second waveform; and transmitting to the user terminal, via
the satellite, the generated one of the first paging signal and the
second paging signal, wherein one of the first amplitude is less
than the second amplitude and the first waveform is different than
the second waveform.
10. The tangible, non-transitory, computer-readable media of claim
9, wherein the computer-readable instructions being capable of
instructing the computer to perform said receiving the input signal
comprises computer-readable instructions being capable of
instructing the computer to receive the input signal via a radio
access network, and wherein the computer-readable instructions
being capable of instructing the computer to perform said
transmitting to the user terminal, via the satellite, the generated
one of the first paging signal and the second paging signal
comprises computer-readable instructions being capable of
instructing the computer to transmit to the user terminal, via the
satellite, the generated one of the first paging signal and the
second paging signal from the radio access network.
11. The tangible, non-transitory, computer-readable media of claim
9, wherein the computer-readable instructions being capable of
instructing the computer to perform said method further comprising
transmitting to the user terminal, via the satellite, the first
paging signal for a predetermined period of time before
transmitting the second paging signal.
12. The tangible, non-transitory, computer-readable media of claim
9, wherein the computer-readable instructions being capable of
instructing the computer to perform said transmitting to the user
terminal, via the satellite, the generated one of the first paging
signal and the second paging signal comprises computer-readable
instructions being capable of instructing the computer to transmit
to the user terminal, via the satellite, the generated one of the
first paging signal and the second paging signal using a signaling
protocol.
Description
BACKGROUND
[0001] The present invention relates to the field of Mobile
Satellite Systems (MSS), in particular, enhanced paging techniques
and Quality of Service (QoS) establishment in mobile satellite
communication systems (MSS).
[0002] The majority of terrestrial cellular systems have evolved to
Third Generation (3G) systems and beyond with a focus on Internet
Protocol (IP) Multimedia services based on Session Initiation
Protocol (SIP). SIP is a signaling protocol widely used for
creating, managing and terminating sessions, such as voice calls,
video conferencing, instant messaging, etc., in an IP based
network. In line with the terrestrial evolution, MSS are also
evolving to 3G services and beyond. The IP Multimedia Subsystems
(EMS) is a key element in the 3G architecture that makes it
possible to provide ubiquitous cellular access to all the services
provided by the internet, for example, web, multimedia, email,
video conferencing to name a few.
[0003] 3G networks interface with General Packet Radio Service
(GPRS) Core Network (CN) to transmit IP packets to external
networks such as the internet. GPRS is a packet oriented mobile
data service, which is maintained by the Third Generation
Partnership Project (3GPP). 3GPP has chosen SEP and the related
protocols for session establishment and management. SIP is used for
signaling between a user terminal and the IMS as well as between
the entities within the IMS.
[0004] In contrast to terrestrial cellular system, typical MSS
operations require a line of sight (LOS) with a satellite.
Typically, when a MSS user is inside a building and there is an
incoming call, an enhanced paging called "Alerting" is used to
notify user of an incoming call. Alerting is expensive in terms of
satellite power needed to reach the users, therefore, there is a
desire by MSS operators to use enhanced paging only for specific
services such as voice. Since the information about the type of
service is indicated inside the SIP message, which is compressed
and/or encrypted by IMS elements, GPRS gateway, which is
responsible for paging and alerting, cannot read the contents of
SIP message. This is further explained with the help of FIG. 1.
[0005] FIG. 1 illustrates a typical mobile satellite system
100.
[0006] As illustrated in the figure, typical mobile satellite
system 100 includes a satellite network 102, a terrestrial mobile
network 104, and an IMS Core Network (CN) 106. Satellite network
102 further includes a User Terminal (UT) 116, which is in the
coverage region of a satellite beam 108. In this example, UT 116
includes a cell phone device. UT 1 116 communicates to a satellite
110 via a communication network signal 154 and to a satellite 112
via a communication network signal 156.
[0007] A GPRS gateway consisting of a Radio Access Network (RAN)
120, a Serving GPRS Support Node (SGSN) 122 and a Gateway GPRS
Support Node (GGSN) 124 connects IMS CN 106 with UT 116 via
satellite 110 or satellite 112.
[0008] Terrestrial mobile network 104 further includes a User
Equipment (UE) 114, which is in the coverage region of a cell 118.
In this example, UE 114 includes a cell phone device. A RAN 126
connects UE 114 to IMS CN 106 via a SGSN 128 and a GGSN 130.
[0009] IMS CN 106 is also connected to a telephone 150 via a Public
Switched Telephone Network (PSTN) 148.
[0010] IMS CN 106 further includes a Proxy-Call Session Control
Function (P-CSCF) 132, a Serving-Call Session Control Function
(S-CSCF) 134, an Interrogating-Call Session Control Function
(I-CSCF) 136, a Media Resource Function Controller (MRFC) 138, a
Media Resource Function Processor (MRFP) 140, a Media Gateway (MGW)
142, a Media Gateway Controller Function (MGCF) 144 and a Signaling
Gateway (SGW) 146. Note that IMS CN 106 only illustrates components
related to SIP signaling in FIG. 1. However, for other
applications, IMS CN 106 may include different components.
Additionally, all the components of MSS 100 are known in the art;
therefore, their functionality is not discussed in detail in this
application.
[0011] RAN 120 is operable to communicate to satellite 110 via a
network signal 158 and to satellite 112 via a network signal 160.
RAN 120 is also operable to communicate with SGSN 122.
[0012] SGSN 122 is operable to transfer data packets to and from UT
116 within its geographical area. Some of the non-limiting
functions of SGSN 122 include packet routing and transfer,
authentication and charging functions of GPRS mobiles, mobility
management and logical link management. The location register of
SGSN 122 stores location information (for example, current cell,
current Visitor Location Register) and user profiles of all GPRS
users registered with SGSN 122.
[0013] GGSN 124 is responsible for sending user packets to external
IP based networks and routing packets back to the mobile uscr. GGSN
124 is operable to convert GPRS packets coming from SGSN 122 into
the appropriate Packet Data Protocol (PDP) format and sends them
out to corresponding packet data network. GGSN 124 has several
functions, including packet inspection for detecting different
types for traffic, which can be used for shaping the traffic under
different network load conditions. GGSN 124 keeps a record of
active mobile users attached to SGSN 122. GGSN 124 is also
responsible for policy control, billing and assigning IP addresses
to mobile users. When GGSN 124 receives data addressed to a
specific user routed through IMS CN 106, it checks if the user is
active. For example, if UT 116 is active, GGSN 124 forwards the
data to SGSN 122, and if UT 116 is not active, the data are
discarded.
[0014] RAN 126 is operable to connect to UE 114 via a terrestrial
network signal 152, which is part of a Universal Terrestrial Radio
Access Network (UTRAN). SGSN 128 is similar to SGSN 122 in
operation and GGSN 130 is similar to GGSN 124 in operation.
[0015] IMS CN 106 is operable to provide mobility management,
session management and transport for IP packet services in addition
to functions such as billing and lawful interception.
[0016] P-CSCF 132 is the first point of contact for the IMS
terminal and is operable to process SIP signaling packets. Some of
the non-limiting functions of P-CSCF 132 include subscriber
authentication, inspecting all signaling from the IMS terminal,
compression and decompression of SIP messages, policy decision
function including QoS and generating charging records. QoS profile
includes different parameters such as traffic class, bit rate,
error rate, transfer delay, etc. to name a few. Traffic class
defines nature of traffic--mainly divided into conversational class
(voice, video telephony, video gaming), streaming class
(multimedia, video on demand, webcast), interactive class (web
browsing, network gaming, database access), and background class
(email, SMS, downloading).
[0017] S-CSCF 134 is the central node of the signaling plane. It is
operable to perform session control in addition to being an SIP
server. Some of the non-limiting functions of S-CSCF 134 include
handling SIP registration, which allows it to bind the user
location and the SIP address, inspecting all signaling messages of
the locally registered users, providing routing services, enforcing
the network operator policies, and deciding which application
server the SIP messages will be forwarded, in order to provide
their services.
[0018] I-CSCF 136 is operable to forward SIP requests or responses
to S-CSCF 134. It functions as another SIP function located at the
edge of an administrative domain.
[0019] MRFC 138 and MRFP 140 together constitute Media Resource
Function (MRF), which provides media related functions such as
media manipulation and playing of tones and announcements. MRFC 138
is operable to receive information coming from S-CSCF 134 and
interpret it to control MRFP 140. MRFP 140 is operable to mix,
source or process media streams in addition to managing access
rights to shared resources.
[0020] MGW 142, MGCF 144 and SGW 146 function as PSTN gateway to
communicate with PSTN 148. MGCF 144 is an SIP endpoint and is
operable to perform call control protocol conversion. It also
controls resources in MGW 142 and interfaces with SGW 146. SGW 146
interfaces with the signaling plane of PSTN 148 and is operable to
transform different protocols to pass to S-CSCF 134 via MGCF 144.
MGW 142 interfaces with the media plane of PSTN 148 and is part of
Media Resources controlled by IMS core functions.
[0021] A session initiated from UE 114 to UT 116 goes through IMS
CN 106 via UTRAN. Similarly, a session initiated from telephone 150
to UT 116 goes through IMS CN 106 via PSTN 148.
[0022] Typically, 3GPP IMS uses SIP based signaling. All the
signaling to and from UT 116 goes through P-CSCF 132. Since most of
the SIP messages are large, 3GPP recommends that SIP messages
between UT 116 and P-CSCF 132 are compressed in order to save
over-the-air bandwidth. As a result, gateway between UT 116 and
P-CSCF 132, namely RAN 120, SGSN 122 and GGSN 124 will not be able
to examine the contents of the signaling message between UT 116 and
P-CSCF 132. In this case, the gateway will not be able to identify
if the call is for voice, fax or something else, and, hence, cannot
generate paging and alerting for the appropriate type of
service.
[0023] When there is signaling directed to a UT, for example, UT
116, this signaling might not be delivered directly to UT 116
depending on the state of UT 116. If UT 116 is in idle mode, SGSN
122 does not have any information about UT 116; therefore, SGSN 122
will page UT 116 before delivering the signaling. UT 116 might be
in a disadvantaged location that normal paging might not be able to
reach UT 116.
[0024] Methods known in the art notify user in a disadvantaged
location by sending a high penetration paging message on a specific
channel so that user can move to a better area if the user desires.
However, the present methods do not distinguish the traffic type of
the incoming call.
[0025] The main problem to solve is how to identify the type of
incoming call. Since SIP signaling is compressed, SGSN 122 and RAN
120 are not able to identify the traffic class. In order to discuss
the procedures to establish a session between two user terminals,
Policy Control and Charging (PCC) rules followed by IMS need to be
discussed, which is explained with the help of FIG. 2.
[0026] FIG. 2 illustrates an example of a typical PCC
architecture.
[0027] As illustrated in the figure, PCC 200 includes an
Application Function (AF) 202, a Policy and Charging Rules
Functions (PCRF) 204, a Policy Charging and Enforcing Function
(PCEF) 206, an Offline Charging System (OFCS) 208, an Online
Charging System (OCS) 210, and a Subscriber Profile Repository
(SPR) 212.
[0028] Interface between different components in FIG, 2, for
example, R.sub.x, G.sub.x, G.sub.y, G.sub.z and S.sub.p, are
interfaces based on diameter protocol, which are known in the art
and not discussed in this application. Diameter is a signaling
protocol that has been specified by Internet Engineering Task Force
(IETF) to perform Authentication, Authorization and Accounting
(AAA) functions in IP based networks. IMS deploys diameter protocol
in most central functionalities and interfaces.
[0029] AF 202 and PCRF 204 are part of P-CSCF 132 in this example.
When a call or a message from a user, for example, UT 116, reaches
P-CSCF 132, it is forwarded to AF 202. AF 202 is operable to
determine the type of message, whether it is a phone all or a
general broadcast. AF 202 forwards the message to PCRF 204 via Rx
interface. PCRF 204 is operable to determine the charging rules for
this message. In order to determine the charging rules, PCRF 204
communicates with SPR 212 using Sp interface, which contains the
set of rules for each user including what is allowed for a
particular user in terms of receiving a call. Based on the
information provided by SPR 212, PCRF 204 derives the rules for
what can be done with the user including the QoS and classification
and forwards it to PCEF 206 via Gx interface.
[0030] PCEF 206 is operable to implement the rule derived by PCRF
204 by either allowing the call or blocking the call. PCEF 206 is a
part of GGSN 124, which analyzes the user traffic and reports the
measured usage to the charging system. For charging, PCEF 206 has
support for both standardized charging mechanisms, off-line
charging (OFCS 208) and online charging (OCS 210). PCEF 206
communicates with OCS 210 via G.sub.y interface and with OFCS 208
via G.sub.x interface. OCS 210 and OFCS 208 are responsible for
billing of the call if the call is allowed. OFCS 208 is operable to
provide an off-line charging system, which implies that the
charging information does not influence the user or its service
until the bill arrives. This methodology is also called post-paid.
OCS 210 is operable to provide an on-line charging system, in which
the charging information cannot influence the service rendered.
[0031] As discussed with reference to FIG. 2, all the components in
PCC 200 work together to determine what the call is for, when there
is an incoming call, and derive the QoS that is used for
paging.
[0032] For 3GPP IMS, which uses SIP as signaling protocol, the SIP
messages between P-CSCF and the mobile terminal are compressed to
save the over-the-air bandwidth. Hence, the traffic type is not
visible to GPRS gateway SGSN in the following two conditions: when
mobile terminal is in PMM-idle (Packet Mobility Management-idle)
mode, the location of UE is not known in the SGSN and paging is
initiated to let known the position of UE at the cell level; and,
when mobile terminal is in RRC-URA_PCH (Radio Resource-Control-WRAN
Registration Area-Paging Channel) mode, SGSN knows about the
position of UE, however, UE still does not have resources available
so that RAN will hold the signaling coming from SGSN and page UE so
that UE can set up the needed resources.
[0033] SIP is in charge of handling and establishing the initiation
of a session. An SIP message mainly contains three sections
detailing the session, timing and media descriptions. A Packet Data
Protocol (PDP) context is created for each session initiated, which
contains the desired characteristics of the specific session,
including the PDP type and the demanded QoS among other parameters.
A PDP context can be viewed as a set of information maintained by
UT, GSSN and SGSN. It contains a PDP type that identifies the type
of Packet Data Network (PDN), the PDP address, QoS information and
other session information. Activating a PDP context refers to
creating the PDP context at the UT, SGSN and GGSN so that UT can
communicate with an entity in PDN using the PDP address maintained
in the PDP context.
[0034] A secondary PDP context activation allows the subscriber to
establish a PDP context with a different QoS profile to the same
PDN. A 3GPP feature called Network Requested Secondary PDP Context
Activation (NRSPCA), which is based on PCC of 3GPP Release 7 as
discussed above, is explained further with reference to FIGS. 3A-3B
to understand how NRSPCA can be applied by IMS CN 106 to outgoing
or incoming calls.
[0035] FIGS. 3A-3B illustrates NRSPCA procedure for incoming calls
in MSS 100.
[0036] For discussion purposes, let's assume that UT 116 is
receiving an incoming call, which in one scenario is initiated by
UE 114 via terrestrial mobile network 104. In another scenario, UT
116 may receive a call from telephone 150 through PSTN 148. In both
the scenarios, UT 116 receives the call through IMS CN 106, which
is using SIP signaling for communication.
[0037] A SIP message typically consists of a header and a message
body. For 3GPP systems using SIP protocol, SIP message bodies are
defined using Session Description Protocol (SDP). Note that the
different steps executed in NRSPCA procedure arc known in the art,
therefore, not discussed in detail.
[0038] Step (1) indicates a SIP INVITE containing a SDP message
arrives at AF 202 (S302).
[0039] Step (2) indicates that SIP INVITE has been received by AF
202 by sending a SIP 100 message (S304).
[0040] SDP received by AF 202 contains information about the
message, for example, for a voice call it may contain information
about vocoder, bandwidth, etc. AF 202 maps those parameters in to
QoS (S306), which includes information about bit-rate, traffic
class, error-rate, etc., in step (3).
[0041] Step (4) indicates that QoS generated by AF 202 is forwarded
to PCRF 204 via Rx interface of Diameter protocol (S308).
[0042] In step (5), PCRF 204 authorizes the QoS mapping to
determine whether the mapping is allowed or not (S310). For
example, if the call requires 64 kb/sec and the user is only
allowed to use up to 4 kb/sec, the call is rejected.
[0043] In step (6), PCRF 204 communicates with SPR 212 via Sp
interface to make a profile request for the user in order to
validate what is allowed for the user (S312).
[0044] SPR 212 sends a response back to PCRF 204 with the user
profile via Sp interface (S314) in step (7).
[0045] In step (8), if the call is authorized, PCRF 204 forwards
the QoS mapping to PCEF 206 via Gx interface of Diameter protocol
(S316).
[0046] As discussed with reference to FIG. 3A, steps 1-8 for NRSPCA
procedure illustrate establishing PCC rules once a session is
initiated. Steps 9-20 are discussed below with the help of FIG.
3B.
[0047] Step (9) indicates that PCC rules have been enforced and
GGSN 124 has all the PCC rules in place. GGSN 124 performs QoS
mapping for UT 116 (S318).
[0048] GGSN 124 forwards Initiate Secondary PDP context activation
to SGSN 122 via G.sub.x interface (S320) in step (10).
[0049] In step (11), assuming UT 116 is in RRC-URA_PCH mode, SGSN
122 sends secondary PDP context activation request to UT 116
through RAN 120 (S322).
[0050] At RAN 120, since UT 116 is in RRC-URA_PCH mode, request
secondary PDP context activation will not be delivered yet so that
UT 116 can setup the needed resources. Instead, RAN 120 will page
UT 116 (S324) in step (12).
[0051] When UT 116 responds to the page, RAN 120 delivers Request
secondary PDP context activation to UT 116 (S326) in step (13).
[0052] In step (14), When UT 116 receives a request to create
secondary PDP context activation, it responds to SGSN 122 by
sending secondary PDP context activation (S328).
[0053] SGSN 122 creates a PDP context request and forwards it to
GGSN 124 (S330) in step (15).
[0054] In step (16), GGSN 124 uses Diameter CCR protocol to
communicate with PCRF 204 via Gx interface to update request for UT
116 (S332).
[0055] PCRF 204 sends an update response back to GGSN 124 using
Diameter CCA protocol via Gx interface (S334) in step (17).
[0056] GGSN 124 responds to SGSN 122 for create PDP context request
via G.sub.x interface (S336) in step (18).
[0057] PCRF 204 communicates with AF 202 using Diameter AAA
protocol via Rx interface (S338) in step (19), indicating that UT
116 has already answered. AF 202 holds the SIP INVITE.
[0058] RAN 120 performs Radio Access Bearer (RAB)/Radio Bearer (RB)
setup in order to allocate resources for UT 116 (S340) in step
(20).
[0059] NRSPCA procedure for incoming calls was discussed with
reference to FIGS. 3A-3B. When SIP INVITE with SDP offer arrives at
P-CSCF 132, with the destination of UT 116, P-CSCF 132 holds it.
P-CSCF 132 then proceeds with NRSPCA procedure. Steps 3-9 discuss
the processes until PCC rules are decided and forwarded to PCEF
206. PCEF 206 then sends Initiate secondary PDP context activation
to SGSN 122. Assuming UT 116 is in RRC-URA_PCH mode, SGSN 122 sends
Request secondary PDP context activation to UT 116 through RAN 120.
At RAN 120, since UT 116 is in RRC-URA_PCH mode, Request secondary
PDP context activation from SGSN 122 will not be delivered yet.
Instead RAN 120 will page UT 116. When UT 116 responds to the page,
RAN 120 then delivers the Request secondary PDP context activation.
Steps 14-20 show the secondary PDP context activation process until
UT 116 receives resource allocations in the form of RAB/RB
configuration.
[0060] In 3G IMS systems where SIP signaling is used, the
information about the type of service is indicated inside the SIP
message. However the entities (SGSN, RAN) responsible for paging
and alerting cannot read the contents of SIP message since SIP
signaling is compressed and/or encrypted by IMS elements before it
reaches SGSN and RAN. Hence enhanced paging based on traffic type
cannot be done.
[0061] There is a need for enhanced paging (alerting) to reach
users in disadvantaged location such as in a building. MSS link
margins arc typically insufficient for paging to reach users in
such disadvantaged scenarios. Physical layer waveform along with an
increase in satellite power can address this issue from a link
budget perspective. However it is desirable that enhanced paging
using increased satellite power is only used for traffic type and
terminal type.
[0062] Many usage scenarios involve connecting one or more external
UEs to wireless user terminals (e.g., 3G satellite terminals).
Individual UEs establish end-to-end sessions, each requiring
different QoS treatments depending on application and data rate.
Appropriate QoS treatment in 3G networks (e.g., 3GPP) is provided
via establishment of Secondary PDP context between the wireless
terminal and core network with the knowledge of application type,
data rate etc. However when an external UE generates sessions, the
wireless terminal is often unable to deduce the application type
and data rate due to encryption and/or compression.
[0063] A key attribute of 3G wireless system is the capability to
provide differentiated QoS across applications. In order for the
system to provide effective QoS differentiation across
applications, the 3G system elements have to be made aware of the
multiplicity of applications that a user terminal has invoked via
secondary PDP contexts with appropriate QoS information elements.
As described above, lack of visibility to applications will prevent
user terminals from establishing secondary PDP contexts with QoS
information elements that arc most optimal for the application. For
example, when the user terminal does not have the visibility of the
application protocol such as Facsimile over IP (FoIP) and Modem
over IP (MoIP), appropriate QoS cannot be established for the user
terminal.
[0064] What is needed is a system and method to provide enhanced
paging and optimum QoS for specific service types, in spite of not
having visibility to the content of SIP message.
BRIEF SUMMARY
[0065] The present invention provides system and method to provide
enhanced paging and optimum QoS for specific service types, in
spite of not having visibility to the content of SIP message.
[0066] In accordance with an aspect of the present invention, a
system is provided for use with an input signal, a satellite and a
user terminal. The input signal corresponds to one of a first type
of data and a second type of data. The satellite is in
communication with the system and the user terminal. The system
includes a communication portion, a determining portion and a
paging portion. The communication portion can receive the input
signal. The determining portion can determine whether the input
signal corresponds to the first type of data or the second type of
data. The paging portion can generate a first paging signal and a
second paging signal, wherein the first paging signal has a first
amplitude and a first waveform and the second paging signal has a
second paging signal and a second waveform. The communication
portion can further transmit to the user terminal, via the
satellite, the first paging signal based on the determining portion
determining that the input signal corresponds to the first type of
data. The communication portion can further transmit to the user
terminal, via the satellite, the second paging signal based on the
determining portion determining that the input signal corresponds
to the second type of data. Further, one of the first amplitude is
less than the second amplitude and the first waveform is different
than the second waveform.
[0067] Additional advantages and novel features of the invention
are set forth in part in the description which follows, and in part
will become apparent to those skilled in the art upon examination
of the following or may be learned by practice of the invention.
The advantages of the invention may be realized and attained by
means of the instrumentalities and combinations particularly
pointed out in the appended claims.
BRIEF SUMMARY OF THE DRAWINGS
[0068] The accompanying drawings, which are incorporated in and
form a part of the specification, illustrate an exemplary
embodiment of the present invention and, together with the
description, serve to explain the principles of the invention. In
the drawings:
[0069] FIG. 1 illustrates a typical mobile satellite system
100;
[0070] FIG. 2 illustrates an example of a typical PCC
architecture;
[0071] FIGS. 3A-3B illustrates NRSPCA procedure for incoming calls
in MSS 100;
[0072] FIG. 4 illustrates a system 400 for enhanced paging, in
accordance with an aspect of the invention;
[0073] FIG. 5 illustrates a mobile satellite system 500, in
accordance with an aspect of the invention;
[0074] FIG. 6 illustrates an embodiment of PCC architecture 600, in
accordance with an aspect of the invention;
[0075] FIGS. 7A-7B illustrate NRSPCA procedure for incoming calls,
in accordance with an aspect of the invention;
[0076] FIGS. 8A-8B illustrate enhanced paging using NRSPCA
procedure, in accordance with an aspect of the invention, when a UT
is in PMM-idle mode;
[0077] FIG. 9 illustrates enhanced paging using NRSPCA procedure,
in accordance with an aspect of the invention, when a UT is in
RRC-URA_PCH mode;
[0078] FIG. 10 illustrates a procedure for enhanced paging using
DSCP, when UT is in PMM-idle mode, in accordance with an aspect of
the invention;
[0079] FIG. 11 illustrates a procedure for enhanced paging using
DSCP, when UT is in RRC-URA_PCH mode, in accordance with an aspect
of the invention;
[0080] FIGS. 12A-12B illustrate NRSPCA procedure for Fax over IP
(FoIP), in an example embodiment of the present invention; and
[0081] FIG. 13 illustrates a flow diagram for Modem over IP (MoIP),
where the resource reservation is done using NRSPCA procedure, in
an example embodiment of the present invention.
DETAILED DESCRIPTION
[0082] In accordance with aspects of the present invention, a
satellite communication system is able to receive an incoming
signal and determine the type of the incoming signal. Based on the
type of incoming signal, the system may modify a paging signal.
[0083] The present invention provides a system and method to enable
the enhanced paging of a UT of a satellite communication system.
The system may receive an incoming signal for a UT and determine
the type of signal. For purposes of discussion, suppose a UT may
receive voice calls and data texts, each having their own type of
signal. In accordance with this aspect of the present invention,
the system may recognize whether the incoming signal, destined for
the UT, is a voice call or data text. The system will page the UT
so that the incoming signal may be forwarded to the UT. In cases
where the UT is unable to receive the page, for example if the user
of the UT is in a building, the system may modify some aspect of
the paging signal, non-limiting examples of which include
amplifying the amplitude of the paging signal and changing the
waveform of the paging signal. Such a modification of the paging
signal may enable the UT to then receive the paging signal.
[0084] The paging aspects of the present invention may be used with
a 3GPP IMS based Mobile Satellite Communication and may use such
techniques judiciously for specific traffic types and terminal
types. In some embodiments, such a modification of the paging
signal may be performed for prescribed types of signal, as opposed
to all signals. For example, the system may be configures to only
amplify the paging signal, when the UT does not respond to an
initial paging signal and when the incoming signal (corresponding
to the page) is a voice signal.
[0085] In accordance with other aspects of the present invention, a
communication device may be tethered to a UT in satellite
communication system. Based on the type of incoming signal that
originates from the tethered device, the system may modify a
quality service.
[0086] For purposes of discussion, suppose a facsimile machine is
sending a facsimile to a destination, through a UT, i.e., the UT is
tethered to the facsimile machine. In accordance with this aspect
of the present invention, the system may recognize the type of the
incoming signal, in this case a facsimile signal. The system will
be able to choose an appropriate quality of service of the
communication between the UT and the destination. In cases where a
plurality of qualities of services are supported by the UT and the
destination, the optimal quality of service may be established. For
example, the present invention provides a method by which
appropriate Secondary PDP context can be established from a UT,
when the UT does not have the visibility to application layer
protocol. In one embodiment of the invention, these two objectives
are achieved by utilizing NRSPCA feature of 3GPP release 7.
[0087] In one embodiment of the invention, NRSPCA procedure
involves interaction between P-CSCF, GGSN, and SGSN that eventually
allows SGSN to identify the traffic type of the incoming call
without looking at the compressed SIP messages. When SIP INVITE
containing SDP offer arrives at P-CSCF, P-CSCF will trigger a
series of steps among P-CSCF (AF), PCRF, and PCEF (GGSN) to create
request secondary PDP context activation for UT. This activation
message, containing traffic class information, is sent to SGSN, so
that SGSN will know the traffic class associated with the incoming
signaling. If SGSN has to page the UT, SGSN will indicate the
traffic class in the Paging Cause. Hence RAN will be able to do
enhanced paging if the Paging Cause is indicating conversational
class. If SGSN does not need to page UT, SGSN will forward request
secondary PDP context activation to UT through RAN. In this case,
if RAN has to page UT, RAN will be able to see the traffic class
from request secondary PDP context activation. Hence RAN can do
enhanced paging if necessary. Note that the method described in
this document will only be used to trigger enhanced paging to the
user if the incoming call is conversational class.
[0088] A system for enhanced paging, in an embodiment of the
present invention, is described with the help of FIG. 4.
[0089] FIG. 4 illustrates a system 400 for enhanced paging, in
accordance with an aspect of the invention.
[0090] As illustrated in the figure, system 400 includes a
communication portion 402, a determining portion 404, a paging
portion 406, a satellite 408, a UT1 410 and a UT2 412. In this
example, communication portion 402, determining portion 404, and
paging portion 406 are distinct elements. However, in some
embodiments, at least two of communication portion 402, determining
portion 404; and paging portion 406 may be combined as a unitary
element. In other embodiments, at least one of communication
portion 402, determining portion 404, and paging portion 406 may be
implemented as a computer having stored therein tangible
computer-readable media for carrying or having computer-executable
instructions or data structures stored thereon. Such tangible
computer-readable media can be any available media that can be
accessed by a general purpose or special purpose computer.
Non-limiting examples of tangible computer-readable media include
physical storage and/or memory media such as RAM, ROM, EEPROM,
CD-ROM or other optical disk storage, magnetic disk storage or
other magnetic storage devices, or any other medium which can be
used to carry or store desired program code means in the form of
computer-executable instructions or data structures and which can
be accessed by a general purpose or special purpose computer. When
information is transferred or provided over a network or another
communications connection (either hardwired, wireless, or a
combination of hardwired or wireless) to a computer, the computer
properly views the connection as a computer-readable medium. Thus,
any such connection is properly termed a tangible computer-readable
medium. Combinations of the above should also be included within
the scope of tangible computer-readable media.
[0091] Communication portion 402 is operable to bi-directionally
communicate with UT2 412 via a network signal 420; bi-directionally
communicate with satellite 408 via a network signal 422;
bi-directionally communicate with determining portion 404 via a
signal 414; and, bi-directionally communicate with paging portion
406 via a signal 418.
[0092] Satellite 408 bi-directionally communicates with UT1 410 via
a network signal 424. In one embodiment, network signal 424 is
similar to communication network signal 154.
[0093] In one embodiment, communication portion 402 receives
network signal 420 via terrestrial network signal 152 and the data
received by communication portion 402 corresponds to communication
data for conversational class. In one embodiment, communication
portion 402 uses SIP protocol to communicate with determining
portion 404, and paging portion 406. In one embodiment,
communication portion 402 provides traffic class information with
the SIP message via signal 414 to determining portion 404.
[0094] Determining portion 404 receives the data from communication
portion 402 and is operable to determine the type of data based on
traffic class information provided by signal 414.
[0095] Paging portion 406 is operable to provide a paging signal to
communication portion 402 via signal 418, based on the type of data
provided by determining portion 404 via a signal 416. In one
embodiment, if the traffic class is conversational class, amplitude
of the paging signal is escalated by paging portion 406. In another
embodiment, if the traffic class is conversational class, the
waveform of the paging signal is changed by paging portion 406.
[0096] Communication portion 402 transmits the paging signal
provided by paging portion 406 to satellite 408 via network signal
422, which forwards it to UT1 410 via network signal 424.
[0097] In one embodiment, communication portion 402 includes a
P-CSCF that initiates a NRSPCA procedure to convey the traffic
class to GGSN that may be part of determining portion 404.
Furthermore, SGSN, and RAN may be part of paging portion 406, which
can do enhanced paging based on the traffic class. This is further
explained with the help of FIG. 5.
[0098] FIG. 5 illustrates a mobile satellite system 500, in
accordance with an aspect of the invention.
[0099] As illustrated in the figure, MSS 500 includes all the
components of MSS 100 except some components of MS 100 arc replaced
by new components, in accordance with aspects of the invention.
Mainly, IMS CN 106, RAN 120, SGSN 122, GGSN 124, and P-CSCF 132 of
MSS 100 arc replaced by an 1MS CN 502, a RAN 504, a SGSN 506, a
GGSN 508, and a P-CSCF 510 respectively in MSS 500.
[0100] As recommended by 3GPP, SIP messages between UT 116 and
P-CSCF 510 are compressed, therefore, RAN 504, SGSN 506, and GGSN
508 arc not able to examine the contents between UT 116 and P-CSCF
510. In one embodiment, NRSPCA procedure is utilized from P-CSCF
510 to GGSN 508, SGSN 506, and RAN 504 to convey the traffic class
associated with the SIP signaling. When SIP INVITE containing SDP
offer arrives at P-CSCF 510, P-CSCF 510 will trigger a series of
steps among P-CSCF 510 and GGSN 508 to create request secondary PDP
context activation for UT 116. This activation message, containing
traffic class information, is sent to SGSN 506, so that SGSN 506
will know the traffic class associated with the incoming
signaling.
[0101] If SGSN 506 has to page UT 116, SGSN 506 will indicate the
traffic class in the Paging Cause. Hence, RAN 504 will be able to
do enhanced paging if the Paging Cause indicates a conversational
class. If SGSN 506 does not need to page UT 116, SGSN 506 will
forward request secondary PDP context activation to UT 116 through
RAN 504. In this case, if RAN 504 has to page UT 116, RAN 504 will
be able to see the traffic class from request secondary PDP context
activation. Hence RAN 504 can do enhanced paging if necessary,
wherein the enhanced paging may include paging with a paging signal
having a larger amplitude and/or paging with a paging signal having
a different waveform than that of the original paging signal.
Different components of MSS 500 work together, in accordance with
aspects of the invention, to provide a method for enhanced paging
and proper QoS establishment, which arc described using FIGS.
6-13.
[0102] FIG. 6 illustrates an embodiment of PCC architecture 600, in
accordance with an aspect of the invention.
[0103] As illustrated in the figure, PCC architecture 600 includes
an AF 602, a PCRF 604 and a PCEF 606, in addition to OFCS 208, OCS
210 and SPR 212 of typical PCC architecture 200.
[0104] AF 602 and PCRF 604 arc part of P-CSCF 510. The basic
functionality of AF 602 and PCRF 604 is similar to AF 202 and PCRF
204 respectively, as described with reference to FIG. 2. In
addition to that, AF 602 and PCRF 604 are operable to follow NRSPCA
procedure, in accordance with an aspect of the invention, in order
to create PCC rules including the traffic class information for
GGSN 508.
[0105] PCC rules are forwarded to PCEF 606, which is part of GGSN
508. PCEF 606 is operable to work with PCRF 604 in order to follow
NRSPCA procedure, in accordance with an aspect of the invention, in
addition to interfacing with OFCS 208 and OCS 210 for charging
rules. PCRF 604 forwards the activation message containing traffic
class information to GGSN 508 so that GGSN 508 will know the
traffic class associated with the incoming signaling. NRSPCA
procedure for incoming calls, in accordance with an aspect of the
invention, is discussed with the help of FIGS. 7A-7B.
[0106] FIGS. 7A-7B illustrate NRSPCA procedure for incoming calls,
in accordance with an aspect of the invention.
[0107] Steps 1-7 in FIG. 7A arc same as the steps 1-7 in FIG. 3A,
except that AF 202 is replaced by AF 602, PCRF 204 is replaced by
PCRF 604 and PCEF 206 is replaced by PCEF 606. Step 8 has been
modified to include traffic class in the QoS profile, in accordance
with an aspect of the invention.
[0108] When SIP INVITE including SDP arrives at P-CSCF 510, with
the destination of UT 116, P-CSCF 510 holds it. P-CSCF 510 then
proceeds with NRSPCA procedure. Steps 3-7 illustrate the processes
until PCC rules arc decided and the call authorization is validated
for the user, as discussed with reference to FIG. 3A.
[0109] If the call is authorized, PCRF 604 forwards the QoS
mapping, including the traffic class, to PCEF 606, in accordance
with an aspect of the invention (S702). The traffic class
information can be used by SGSN 506 and GGSN 508 for enhanced
paging if the paging cause indicates conversational class. Steps
9-20, in accordance with an aspect of the invention, are discussed
with the help of FIG. 7B.
[0110] As illustrated in FIG. 7B, in step (9), PCC rules have been
enforced and GGSN 508 has all the PCC rules in place. PCEF 606
performs end-to-end QoS mapping for IP-Universal Mobile
Telecommunication System (UMTS) by providing QoS information
elements that are most optimal across different applications
(S704). PCEF 606 sends initiate secondary PDP context activation to
SGSN 506 via G.sub.n interface of diameter protocol (S706).
[0111] When UT 116 responds to the page, steps 13-20 are same as
illustrated with reference to FIG. 3B.
[0112] Assuming UT 116 is in RRC-URA_PCH mode, SGSN 506 sends
secondary PDP context activation request to UT 116 through RAN 504
(S708) in step (11).
[0113] At RAN 504, since UT 116 is in RRC-URA_PCH mode, request
secondary PDP context activation will not be delivered yet.
Instead, RAN 504 will page UT 116 (S710) in step (12). In one
embodiment, if UT 116 does not respond to the page after a few
pre-determined times, RAN 504 will elevate the paging level, as
will be discussed with the help of FIGS. 8A-8B. It should be noted
however, that the waveform of the paging signal may additionally or
alternatively be modified.
[0114] When a UT is in PMM-idle mode, enhanced paging using NRSPCA
is described with the help of FIGS. 8A-8B.
[0115] FIGS. 8A-8B illustrate enhanced paging using NRSPCA
procedure, in accordance with an aspect of the invention, when a UT
is in PMM-idle mode.
[0116] As illustrated in FIG. 8A, SIP INVITE with SDP offer for
voice call arrives at P-CSCF 510 (S802). P-CSCF 510 interacts with
AF 602, PCRF 604, and PCEF 606 to generate PCC rules (S804), as
discussed with reference to FIGS. 6, 7A-7B. Based on the PCC rules,
PCEF 606 sends Initiate Secondary PDP context activation to SGSN
506 (S806).
[0117] Since UT 116 is in PMM-idle mode, SGSN 506 will page UT 116
through RAN 504 (S808). Page from SGSN 506 will have paging cause
set to conversational class. When RAN 504 receives paging from SGSN
506 with paging cause set to conversational class, RAN 504 first
will do normal paging in the area that UT 116 might be located
(S810). When paging timer is expired without any response from UT
116, RAN 504 will do paging escalation meaning RAN 504 will expands
the paging area. When there is still no response from UT 116, RAN
504 will do the enhanced paging (S812). Enhanced paging is a paging
with higher power so that the paging signal can penetrate user in
disadvantaged area. The steps after enhanced paging from RAN 504
arc discussed with the help of FIG. 8B.
[0118] As illustrated in FIG. 8B, when UT 116 receives enhanced
paging, it will notify the user using a special tone so that the
user can move to a better reception area (S814). In some cases,
escalated alerting is used for the special tone (S816). Once UT 116
responds to the enhanced paging (S818), the secondary PDP context
activation is continued (S820). When the secondary PDP context has
been established, i.e. UT 116 has the resources to conduct
communication (S822), SIP INVITE will be sent to UT 116. Finally,
UT 116 will exchange SIP messages with the calling party through
P-CSCF 510 (S824). Rest of SIP signaling for SIP INVITE is not
shown (S826).
[0119] When a UT is in RRC-URA_PCH mode, enhanced paging using
NRSPCA is described with the help of FIG. 9.
[0120] FIG. 9 illustrates enhanced paging using NRSPCA procedure,
in accordance with an aspect of the invention, when a UT is in
RRC-URA_PCH mode.
[0121] As illustrated in FIG. 9, SIP INVITE with SDP offer for
voice call arrives at P-CSCF 510 (S902). P-CSCF 510 interacts with
AF 602, PCRF 604, and PCEF 606 to generate PCC rules (S904), as
discussed with reference to FIGS. 6, 7A-7B. Based on the PCC rules,
PCEF 606 sends Initiate Secondary PDP context activation to SGSN
506 (S906).
[0122] In RRC-URA_PCH mode, UT 116 has established connection with
SGSN 506 but RAN 504 has not allocated any resources yet. Thus SGSN
506 will forward the Initiate Secondary PCP context activation to
UT 116 (S908). However, since RAN 504 has not allocated any
resources yet, RAN 504 will not forward this message to UT 116,
instead RAN 504 will page UT 116 (S910). When the paging fails, RAN
504 will do the enhanced paging (S912). When UT 116 receives
enhanced paging, it will notify the user using a special beep so
that the user can move to a better reception area (S914). When UT
116 responds to the enhanced paging, secondary PDP context
activation proceeds as discussed for PMAI-idle mode (S916). SIP
messages arc exchanged between UT 116 and the calling party via
P-CSCF 510.
[0123] FIGS. 7A, 7B, 8A, 8B, and 9 illustrated an embodiment of the
invention using NRSPCA procedures, where enhanced paging is
achieved for conversational class by populating the QoS profile in
the SIP message with the traffic class. Two different modes were
discussed for incoming calls, where enhanced paging is activated
based on the traffic class. In RRC-URA_PCH mode, the paging is
initiated at the RAN. RAN is able to identify the traffic type of
the incoming call from the request secondary PDP context activation
that is sent by SGSN to the mobile terminal via RAN. In PMM-idle
mode, the paging is initiated at the SGSN. For SGSN initiated
paging, SGSN notifies RAN regarding the traffic type of this paging
in the paging cause. Hence RAN can do enhanced paging if
appropriate.
[0124] In another embodiment of the present invention, enhanced
paging is achieved using a method known as Differentiated Services
Code Point (DSCP). Use of DSCP field in the IP header for packet
classification purposes is known in the art. In DSCP method, when
P-CSCF observes that an incoming call is for traffic type that is
eligible for enhanced paging, P-CSCF will mark this traffic with
DSCP code. For example, P-CSCF will set the DSCP code to a fixed
number to indicate the conversational class that will be known by
the SDP being executed by SGSN and GGSN. SGSN can determine from
the traffic type that this traffic is eligible for enhanced paging.
Hence, for paging from SGSN, SGSN will populate the paging cause
with enhanced paging cause code. For paging by RAN, RAN can
escalate paging into enhanced paging by investigating the DSCP of
the packet. The DSCP code will be chosen judiciously by network
operator so that it will not disturb the network operation.
[0125] The procedure for enhanced paging using DSCP, in an example
embodiment of the invention, is discussed with the help of FIGS.
10-11.
[0126] FIG. 10 illustrates a procedure for enhanced paging using
DSCP, when UT is: in PMM-idle mode, in accordance with an aspect of
the invention.
[0127] As illustrated in the figure, AF 602 receives SIP INVITE
message indicating traffic that is eligible for enhanced paging
(S1002). AF 602 indicates that SIP INVITE has been received by
sending a SIP 100 message (S1004). AF 602 populates the DSCP with
an appropriate code (for example, conversational class) and then
sends it to GGSN 508 (S1006). GGSN 508 forwards the message to SGSN
506 (S1008). SGSN 506 sends paging to RAN 504 with paging cause
indicating that this paging is eligible for enhanced paging
(S1010). RAN 504 will page UT 116 (S1012). When paging timer
expires without any response from UT 116 (S1014), RAN 504 will do
paging escalation (S1016).
[0128] FIG. 11 illustrates a procedure for enhanced paging using
DSCP, when UT is in RRC-URA_PCH mode, in accordance with an aspect
of the invention.
[0129] As illustrated in the figure, for an SIP INVITE message
indicating traffic that is eligible for enhanced paging, steps
(S1002), (S1004), (S1006) and (S1008) are same as described with
reference to FIG. 10, when UT is in PMM-idle mode,
[0130] When UT is in RRC-URA_PCH mode, SGSN 506 will send the SIP
INVITE message to RAN 504 populated with the DSCP by AF 602
(S1102). RAN 504 will page UT 116 (S1104). When paging tinier
expires without any response from UT 116 (S1106), RAN 504 will do
paging escalation (S1108).
[0131] As discussed with reference to FIGS. 10-11, in one example
embodiment, enhanced paging can be achieved by marking the packet
with an appropriate DSCP code, which is done by the P-CSCF. SGSN
can populate the paging cause with enhanced paging code based on
the DSCP code provided. Alternatively, RAN can escalate paging to
enhanced paging by examining the DSCP code.
[0132] The methods described above with reference to FIGS. 4-11
provide method of achieving selective alerting using NRSPCA
procedures for mobile terminated sessions by relying upon the QoS
information element used in NRSPCA procedures for mobile terminated
sessions.
[0133] Next, a method is discussed in an example embodiment,
whereby NRSPCA procedure can be used to establish appropriate QoS
attributes even for mobile originated sessions. Suppose there arc
calls from external device, e.g., a VoIP phone connected to UT or
external fax machine connected to UT or external modem data
connected to UT. In this case, the UT is typically unaware of the
actual application being invoked from the external device and is
therefore unable to invoke appropriate QoS attributes for the
session. In this case, a method, in accordance with an aspect of
the invention, is described by which NRSPCA will be applied from
the core network to establish appropriate QoS for mobile originated
sessions.
[0134] FIGS. 12A-12B illustrate NRSPCA procedure for FoIP, in an
example embodiment of the present invention.
[0135] FIGS. 12A-12B illustrate an example embodiment of the
invention for FoIP using T.38 protocol, which is an International
Telecommunication Union (ITU) recommendation for allowing
transmission of Fax over IP networks in real time. A Fax1 device
1202 initiates a fax transmission directed to a Fax2 device 1218
(S1220). An external fax T.38 gateway1 (GW1) 1204 starts fax call
as voice call in an SIP INVITE (S1222). A UT1 1202 receives SIP
INVITE but is unable to decipher the voice call since UT1 1202 is
unaware of SIP INVITE. SIP INVITE is forwarded all the way to a CN
1210 (S1224). Note that CN 1210 includes SGSN, GGSN and IMS CN in
an example embodiment. CN 1210 determines from SIP INVITE that this
is a voice call and uses NRSPCA to reserve resources for voice call
(S1226).
[0136] CN 1210 sends an alerting message to a RAN2 1212 (S1228) and
forwards the SIP INVITE to a UT2 1214 (S1230).
[0137] UT2 1214 forwards the SIP INVITE to a GW2 1216 (S1232).
[0138] GW2 1216 sends a voice call to Fax2 1218. When fax2 1218
receives this call, it sends a ringing tone, which goes through UT2
1214, CN 1210, UT1 1202 to GW1 1204 (S1234). GW1 sends back a
ringback tone to fax1 1202 (S1236).
[0139] Fax1 1202 sends a fax calling (CNG) tone to GW1 1204 once
the dialing is complete (S1238). Fax2 1218 sends a CED signal after
answering the call (S1240). GW2 1216 sends an OK signal through UT2
1214, CN 1210, UT1 1202 to GW1 1204 (S1242). In response to OK
signal, GW1 1204 sends an ACK signal back to GW2 1216 (S1244).
[0140] Once the connection between fax 11202 and fax2 1218 has been
setup and they are communicating with each other, a fax calling
tone (CNG) is sent (S1246). GW1 1204 sends a voice encoded CNG
packet to GW2 1216 (S1248). Once GW2 1216 receives a CED signal
from fax2 1218 (S1250), it sends a voice encoded CED packet to GW
11204 (S1252). CED signal is forwarded to fax1 1202 (SI 254). The
remaining steps are discussed with the help of FIG. 12B.
[0141] In FIG. 12B, once GW2 1216 detects that this is a fax call
(S1256), it sends SIP INVITE again (RE-INVITE) to indicate fax call
(S1258). CN 1210 gets the SIP RE-INVITE and notices that the
resources have to be updated. CN 1210 updates the resources for UT1
1206 using Modify secondary PDP context procedures (S1260).
[0142] GW1 1204 and GW2 1216 exchange OK signal (S1262) and ACK
signal (S1264).
[0143] Resources for UT1 1206 are updated (S1266). Fax message and
data is exchanged with muted voice (S1268).
[0144] FIG. 13 illustrates a flow diagram for MoIP, where the
resource reservation is done using NRSPCA procedure, in an example
embodiment of the present invention.
[0145] MoIP Gateway follows ITU V.150.1 Modem over IP standard.
FIG. 13 illustrates an example embodiment, when the modem has the
capability as a MoIP Gateway. However, this method is also
applicable when the modem is connected to a separate MoIP
gateway.
[0146] When a destination number is dialed, a MoIP GW 11302 sends
SIP INVITE with SDP indicating modem call to a UT1 1304. When SIP
INVITE arrives at a CN 1308, CN 1308 starts NRSPCA procedures. CN
1308 then forwards SIP INVITE to a destination modem 1312. The
following are standard procedures to setup modem call.
[0147] As discussed with reference to FIGS. 12A-12B and 13, NRSPCA
procedure can be used to establish appropriate QoS attributes for
mobile originated sessions, for example, FoIP and MoIP, in
accordance with aspects of the invention. Since fax or modern data
calls from external devices attached to UT do not have the ability
to request resources, proposed NRSPCA procedure provides resources
to such calls.
[0148] A system and method to enable the enhanced paging for 3GPP
IMS based Mobile Satellite Communication was discussed, in
accordance with aspects of the invention. When SIP INVITE
containing SDP offer arrives at P-CSCF, P-CSCF triggers a series of
steps among P-CSCF (AF), PCRF, and PCEF (GGSN) to create request
secondary PDP context activation for UT. The activation message,
containing traffic class information, is sent to SGSN, so that SGSN
knows the traffic class associated with the incoming signaling. If
SGSN has to page the UT, SGSN indicates the traffic class in the
Paging Cause. Hence RAN is able to do enhanced paging if the Paging
Cause is indicating conversational class. If SGSN does not need to
page UT, SGSN forwards request secondary PDP context activation to
UT through RAN. In this case, if RAN has to page UT, RAN is able to
see the traffic class from request secondary PDP context
activation. Hence RAN can do enhanced paging if necessary.
[0149] While the description and illustrations discussed in this
application refer to 3GPP specifications and procedures, this
concept of Alerting and QoS Establishment can also be applied to
non-3GPP systems and satellite systems that are in Medium Earth
Orbit (MEO), Low Earth Orbit (LEO) or Geosynchronous (GEO)
orbits.
[0150] The foregoing description of various preferred embodiments
of the invention have been presented for purposes of illustration
and description. It is not intended to be exhaustive or to limit
the invention to the precise forms disclosed, and obviously many
modifications and variations arc possible in light of the above
teaching. The example embodiments, as described above, were chosen
and described in order to best explain the principles of the
invention and its practical application to thereby enable others
skilled in the art to best utilize the invention in various
embodiments and with various modifications as are suited to the
particular use contemplated. It is intended that the scope of the
invention be defined by the claims appended hereto.
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