U.S. patent application number 12/080015 was filed with the patent office on 2009-10-01 for method and apparatus for communication between wireless telecommunications networks of different technology types.
Invention is credited to Violeta Cakulev, Michael Francis Dolan, Subramanian Vasudevan, Lily H. Zhu.
Application Number | 20090245200 12/080015 |
Document ID | / |
Family ID | 40912071 |
Filed Date | 2009-10-01 |
United States Patent
Application |
20090245200 |
Kind Code |
A1 |
Cakulev; Violeta ; et
al. |
October 1, 2009 |
Method and apparatus for communication between wireless
telecommunications networks of different technology types
Abstract
For handover between wireless telecommunications networks of
different technology types, an air interface is set up between a
first node 4 included in a network of a first technology type and a
second node 10 included in a network of a second different
technology type. Signaling messaging, in accordance with the second
technology type, is related to handover of a mobile terminal from
the network of the first technology type to the network of the
second technology type. The signaling messaging is encapsulated in
a container for transmission over the signaling interface. An
identifier is associated with the container to indicate that it
encapsulates the signaling messaging. When the identifier is
detected at the first node, the container is sent over the
interface to the second node. In one method in accordance with the
invention, the first technology type is WiMAX and the identifier is
a special service flow identifier. This may be detected at an
Access Services Network Gateway (ASN GW), for example. A method in
accordance with the invention thus permits the use of logical radio
channels for encapsulating inter-technology signaling.
Inventors: |
Cakulev; Violeta; (Morris
Plains, NJ) ; Dolan; Michael Francis; (Bolingbrook,
IL) ; Vasudevan; Subramanian; (Morristown, NJ)
; Zhu; Lily H.; (Parsippany, NJ) |
Correspondence
Address: |
Docket Administrator - Room 2F-192;Alcatel-Lucent USA Inc.
600-700 Mountain Avenue
Murray Hill
NJ
07974
US
|
Family ID: |
40912071 |
Appl. No.: |
12/080015 |
Filed: |
March 31, 2008 |
Current U.S.
Class: |
370/331 |
Current CPC
Class: |
H04W 36/14 20130101;
H04W 92/20 20130101; H04W 36/08 20130101; H04W 36/0066
20130101 |
Class at
Publication: |
370/331 |
International
Class: |
H04Q 7/00 20060101
H04Q007/00 |
Claims
1. A method for communication between wireless telecommunications
networks of different technology types, including the steps of:
setting up an air interface between a MS and a first node included
in a network of a first technology type; setting up a signaling
interface between the first node included in a network of a first
technology type and a second node included in a network of a second
different technology type providing signaling messaging over the
above signaling interface in accordance with the second technology
type, the signaling messaging being related to handover of a mobile
terminal from the network of the first technology type to the
network of the second technology type; encapsulating the signaling
messaging in a container for transmission over the signaling
interface; associating an identifier (from the over-the-air
interface message) with the container to indicate that it
encapsulates said signaling messaging; and, when the identifier is
detected at the first node, sending the container over the
signaling interface to the second node.
2. The method as claimed in claim 1 and wherein the first
technology type is WiMAX and the identifier is a special service
flow identifier.
3. The method as claimed in claim 2 and wherein the second
technology type is HRPD.
4. The method as claimed in claim 3 and wherein the signaling
interface is an S101 interface.
5. The method as claimed in claim 2 and wherein the identifier is
detected at the Access Services Network Gateway (ASN GW).
6. The method as claimed in claim 1 and wherein the first
technology type is HRPD.
7. The method as claimed in claim 6 wherein the identifier is in
the form of a signaling link protocol (SLP) identifier or a new
identifier that is equivalent to SLP (the common characteristics of
this new identifier with SLP is: they boith terminate at HRPD RNC
and will not be forwarded to HRPD PDSN).
8. The method as claimed in claim 1 and wherein the first and
second technology types are respective ones of the following
technology types: High Rate Packet Data (HRPD); WiMAX; Long Term
Evolution (LTE); and Ultra Mobile Broadband (UMB).
9. The method as claimed in claim 8 and wherein the interface is an
S101 interface.
10. A node for a wireless telecommunications network of a first
technology type, the node comprising: a detector for detecting an
identifier associated with a message container, the identifier
indicating that the container encapsulates handover signaling
messaging in accordance with a second technology type different to
the first technology type; and a transmitter for transmitting a
container having the detected identifier over an air interface with
another node included in a wireless telecommunications network of
the second technology type.
11. The node as claimed in claim 10 and wherein the first and
second technology types are respective ones of the following
technology types: High Rate Packet Data (HRPD); WiMAX; Long Term
Evolution (LTE); and Ultra Mobile Broadband (UMB).
12. The node as claimed in claim 10 and wherein the interface is an
S101 interface.
13. A mobile terminal having the capability of communicating with
networks of at least two respective different technology types and
operative, during handover preparation for handover from a first
network of a first technology type to a second network of a second
technology type, to add an identifier to signaling messaging for
use in the second network to indicate that the signaling messaging
is to be tunneled from the first network to the second network over
an interface.
14. The mobile terminal as claimed in claim 13 and wherein the
first and second technology types are respective ones of the
following technology types: High Rate Packet Data (HRPD); WiMAX;
Long Term Evolution (LTE); and Ultra Mobile Broadband (UMB).
15. The mobile terminal as claimed in claim 13 and wherein the
interface is an S101 interface.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a method and apparatus for
communication between wireless telecommunications networks of
different technology types, and more particularly, but not
exclusively, where the different technology types are what is
termed `fourth generation`, or `4G`, technologies.
BACKGROUND OF THE INVENTION
[0002] Currently, efforts in mobile telecommunications developments
are directed to providing broadband data communications, known as
3.5G and 4G, using various competing radio access technologies
(RATs) aiming to achieve high bandwidth combined with low latency,
high efficiencies and flexibility. High Rate Packet Data (HRPD),
also referred to as 1xEV-DO or High Data Rate (HDR), is a
high-speed CDMA-based wireless data technology. WiMAX is an IEEE
standard 802.16e for mobile technology. Long Term Evolution (LTE)
is a Third Generation Partnership Project (3GPP) for enhancing
UMTS. Ultra Mobile Broadband (UMB) is a 3GPP2 project.
[0003] A mobile terminal (MS) may have a capability for
communicating with networks of different technology types. If
conditions deteriorate, for example, when the mobile terminal is
connected to a node in one network, it may be desirable to transfer
it to a new connection, which may be another node of the same
network or a node in a different network. Signaling messaging is
required between the mobile terminal and elements of a potential
new target network node so as to complete handover preparation, for
example, by transferring information regarding the context of the
mobile terminal, and to carry out handover from a source node to a
target node once the necessary steps have been fulfilled. If
handover involves transfer between networks of different technology
types, some mechanism must be provided to permit signaling
messaging for use in making a connection between the mobile
terminal and the target node to be sent to the target network to
establish communication between them.
[0004] One problem during inter-technology handover (HO) is timing
for real-time services. It is desirable that the traffic
interruption during such HO is kept within 300 ms to make the HO
seamless and reduce the likelihood of real-time service being.
[0005] Each Radio Access Technology uses different protocols and
architectures to establish an IP service for an MS. Many of them
involve the setup of the Radio Access Network session for the MS
and the setup of L3 connectivity. For example: WiMax requires WiMax
RAN access and WiMax session and IP session setup. HRPD requires
HRPD session, PPP session and MIP session setup. Each one of these
setups may take anytime between 1-5 seconds. Therefore, the setup
of these sessions and reservation of the resources must be done in
a "make-before-break" fashion, that is, before the actual HO
execution. This is achieved by "tunneling" of target technology
messages over the current serving technology.
[0006] One possible tunneling mechanism is to rely directly on the
IP network of the serving technology, which may be termed IP
encapsulation, and tunnel the "pre-registration" directly from
serving technology, via the Home Agent (HA), to the target
technology's Radio Access Network (RAN).
BRIEF SUMMARY OF THE INVENTION
[0007] According to a first aspect of the invention, a method for
communication between wireless telecommunications networks of
different technology types includes setting up an air interface
between a first node included in a network of a first technology
type and a second node included in a network of a second different
technology type. Signaling messaging, in accordance with the second
technology type, is related to handover of a mobile terminal from
the network of the first technology type to the network of the
second technology type. The signaling messaging is encapsulated in
a container for transmission over the interface. An identifier is
associated with the container to indicate that it encapsulates the
signaling messaging. When the identifier is detected at the first
node, the container is sent over the interface to the second node.
In one method in accordance with the invention, the first
technology type is WiMAX and the identifier is a special service
flow identifier. This may be detected at an Access Services Network
Gateway (ASN GW), for example. A method in accordance with the
invention thus permits the use of logical radio channels for
encapsulating inter-technology signaling.
[0008] By using a method in accordance with the invention, it is
not necessary to rely on IP tunneling and thus security issues
associated with IP communications, such as Denial of Service
attacks, hijacking of sessions and exposure of RAN equipment to
hackers, may be avoided during the handover process. Additionally,
by using the invention, the source node may be made aware that the
mobile terminal is signaling to the second technology in
preparation for a handover, whereas this would not visible to a
source node if IP encapsulation were to be used instead. Also, by
employing a method in accordance with the invention, delays are
reduced as there is no need to rely on existing L3 protocols, this
being particular advantageous for real time applications such as
speech.
[0009] In one method in accordance with the invention, the first
technology type is WiMAX and the second technology type may be
HRPD, for example. The method may also be applied where the first
technology type is HRPD and the second technology type is
WiMAX.
[0010] A method in accordance with the invention may use first and
second technology types that are respective ones of the following
technology types: High Rate Packet Data (HRPD); WiMAX; Long Term
Evolution (LTE); and Ultra Mobile Broadband (UMB). Future
evolutions of these or other types of technology may be used.
[0011] In one method in accordance with the invention, the
interface is an S101 interface, although another common interface
standard may be adopted instead. The S101 interface has been
proposed for use in inter-RAT communications for communication
between LTE and HRPD networks. By adopting the S101 interface for
other combinations of technology types, compatibly issues are
reduced and there is no need to modify interfaces between different
types for each specific combination, aiding backward compatibility
and easing later system upgrades and providing a scalable
solution.
[0012] Where the first technology type is HRPD, the identifier may,
in one method, be in the form of a signaling link protocol (SLP)
identifier.
[0013] In a method in accordance with the invention, the interface
may be an S101 interface. This is an interface defined initially
for use between an LTE network and an HRPD network. The present
inventors have realized that such an interface may be more
generally applied for use as an interface between networks with
other combinations of technology types.
[0014] According to a second aspect of the invention, a node for a
wireless telecommunications network of a first technology type, the
node comprises a detector for detecting an identifier associated
with a message container, the identifier indicating that the
container encapsulates handover signaling messaging in accordance
with a second technology type different to the first technology
type. It further comprises a transmitter for transmitting a
container having the detected identifier over an air interface with
another node included in a wireless telecommunications network of
the second technology type. The first and second technology types
may be respective ones of the following technology types: High Rate
Packet Data (HRPD); WiMAX; Long Term Evolution (LTE); and Ultra
Mobile Broadband (UMB). Other types of technology or evolutions of
these may be used.
[0015] According to a third aspect of the invention, a mobile
terminal having the capability of communicating with networks of at
least two respective different technology types is operative,
during handover preparation for handover from a first network of a
first technology type to a second network of a second technology
type, to add an identifier to signaling messaging for use in the
second network to indicate that the signaling messaging is to be
tunneled from the first network to the second network over an
interface. The first and second technology types may be respective
ones of the following technology types: High Rate Packet Data
(HRPD); WiMAX; Long Term Evolution (LTE); and Ultra Mobile
Broadband (UMB). Other types of technology or evolutions of these
may be used.
BRIEF DESCRIPTION OF THE DRAWING
[0016] Some embodiments and methods in accordance with the present
invention are now described by way of example only, and with
reference to the accompanying drawings, in which:
[0017] FIG. 1 schematically illustrates a wireless
telecommunications system having two networks of respective
different technology types.
DETAILED DESCRIPTION
[0018] With reference to FIG. 1, an access terminal (or mobile
terminal) (AT/MS) 1 is in communication with a WiMAX network 2,
being connected to a base station 3. The base station 3 is
connected via an ASN GW 4 to common core network elements shown at
5 and including AAA 6, PCRF 7, Home Agent/Location Manager (HA/LMA)
8 and IMS 9 entities.
[0019] Another network of a second technology type, HRPD, includes
an HRPD AN*/PCF second node 10 which connects to a PDSN 11 via the
A10/A11 interface 12. The PDSN 11 connects to the common core
network elements shown at 5.
[0020] In a Wimax network, all traffic received over the Wimax air
interface from the MS 1 is sent from the Foreign Agent (FA), which
is part of the ASN-GW 4, to the Home Agent (HA). The ASN GW 4 is
the network node that performs RAN control and routing. After
transmission to the HA, the traffic is subsequently routed to its
destination using standard IP routing.
[0021] In Wimax air interface, a MS may have multiple service flows
(SF) simultaneously, and each SF has a unique identifier (called
SFID). The Wimax ASN-GW 4 is the network element that performs IP
classification and mapping of IP flow to Wimax SF and vice versa.
To create the equivalent of S101 interface similar to that between
LTE and HRPD, the ASN GW 4 is able to detect all tunneled signaling
messages, intercepting them to perform special routing to HRPD RAN
instead of going via the standard WiMax FA to HA tunneling
mechanism.
[0022] In a method in accordance with the invention, a special
service flow is created. This is a flow of traffic that can be
identified by its unique ID in the RAN, and not by its IP
classifier such as source/destination address, source/destination
port number, protocol ID, and so on.
[0023] In a WiMax to HRPD handoff, the ASN-GW 4 creates a secure
tunnel between itself and the HRPD RAN (there could be more than
one tunnel for load sharing purpose) to carry a S101 interface 13
between ASN-GW 4 and HRPD RAN 10. The MS 1 uses a special flow
(from AT/MS 1 to ASN-GW 4) to send any HO trigger it may detect,
for example, such as change in signal strength). The ASN-GW 4 also
uses a special flow (from ASN-GW 4 to AT 1) to convey any network
information (such as neighbor list of co-located HPRD BSs and/or
border cell notification to AT) to assist HO. For all
AT/MS-originated messages (destined for HRPD RAN for HRPD session
setup), the ASN-GW 4 recognizes the special service flow ID (which
is a unique globally known SF ID) and uses the secure tunnel
established earlier as S101 to deliver messages, the signaling
messaging being encapsulated in a container which also includes an
identifier as to its contents.
[0024] From the point of view of the ASN-GW 4, all the tunneled
signaling messages from HRPD RAN are received as if they come
directly from a Wimax terminal via Wimax BS that carries the Wimax
air interface over the Wimax R6 interface (such as SS association
as if AT/MS has performed a successful ranging, authentication
exchange, initial SF creation, IP connectivity setup, etc).
[0025] Thus, the special service flow initiated by ASN-GW 4 and/or
AT/MS 1 is used for intercepting and sending HRPD session set-up
messages between AT and HRPD RAN (sent as a WiMAX payload). This
avoids the need for a special tunneling capability on the WiMAX air
interface.
[0026] For handover from HRPD to one of LTE, Wimax or UMB networks,
for example, the same mechanism may be applied. HRPD air interface
has the concept of RLP flows and SLP flow. RLP flow corresponds to
A10 connection (R-P) with PDSN. SLP flow is used for HRPD signaling
messages and it terminates in HRPD RNC. Each MS may support
multiple RLP flows, similar to service flows in WiMax. By applying
the same technique of identify the HO tunneling message using the
special SLP-like flow ID, the HRPD RNC can create the same S101
interface from HRPD to LTE, Wimax or UMB, as applicable.
[0027] Thus, it is possible to minimize changes to deployed
networks while providing Network Control of handover, to maintain
security of HRPD RAN, and use single Interface from HRPD to a
number of emerging technologies, such as WiMAX, LTE and UMB.
[0028] A method and embodiment in accordance with the invention may
be deployed without modifying either the HRPD or WiMAX radio
interfaces, thus avoiding impact on existing radio interfaces.
Changes may be isolated to specific equipment such as RNCs. This
potentially leads to a large cost saving over both making radio
interface changes and adding security mechanisms such as
firewalls.
[0029] Coordination of the radio handover with the bearer path
switching is critical, and cannot be efficiently managed by the
mobile alone. The network must be involved. This special flow-based
tunneling provides operators with security and flexibility for
optimization compared to regular IP connection.
[0030] The re-use of certain approaches from LTE to HRPD handover
allows an operator for flexibility in making business decisions
regarding technologies.
[0031] The present invention may be embodied in other specific
forms without departing from its spirit or essential
characteristics. The described embodiments are to be considered in
all respects only as illustrative and not restrictive. The scope of
the invention is, therefore, indicated by the appended claims
rather than by the foregoing description. All changes that come
within the meaning and range of equivalency of the claims are to be
embraced within their scope.
* * * * *