U.S. patent application number 12/551073 was filed with the patent office on 2009-12-31 for event notification in a hybrid network.
This patent application is currently assigned to Telefonaktiebolaget LM Ericsson (Publ). Invention is credited to Erik Colban, Vibhor Julka.
Application Number | 20090323623 12/551073 |
Document ID | / |
Family ID | 35134600 |
Filed Date | 2009-12-31 |
United States Patent
Application |
20090323623 |
Kind Code |
A1 |
Julka; Vibhor ; et
al. |
December 31, 2009 |
Event Notification in a Hybrid Network
Abstract
When a mobile station requests circuit services notifications
through a packet switched network, a mobile switching center sets a
forwarding indicator. When the MSC detects an event indicative of a
change in the status of the mobile station, the MSC sends an event
notification to the packet switched network if the forwarding
indicator is set to true. In the packet switched network, the base
station can use the event notifications to manage communication
resources used for packet data communications with the mobile
station.
Inventors: |
Julka; Vibhor; (San Diego,
CA) ; Colban; Erik; (San Diego, CA) |
Correspondence
Address: |
COATS & BENNETT, PLLC
1400 Crescent Green, Suite 300
Cary
NC
27518
US
|
Assignee: |
Telefonaktiebolaget LM Ericsson
(Publ)
Stockholm
SE
|
Family ID: |
35134600 |
Appl. No.: |
12/551073 |
Filed: |
August 31, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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|
11094951 |
Mar 31, 2005 |
7606197 |
|
|
12551073 |
|
|
|
|
60603694 |
Aug 23, 2004 |
|
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60652585 |
Feb 14, 2005 |
|
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Current U.S.
Class: |
370/329 |
Current CPC
Class: |
H04Q 2213/13296
20130101; H04W 72/04 20130101; H04W 68/12 20130101; H04W 8/245
20130101; H04Q 2213/13396 20130101; H04Q 2213/13098 20130101; H04W
36/0022 20130101; H04Q 3/0045 20130101 |
Class at
Publication: |
370/329 |
International
Class: |
H04W 40/24 20090101
H04W040/24 |
Claims
1. A method of managing communication resources in a hybrid network
including a circuit switched network and a packet switched network,
the method comprising: establishing packet data communications
between said packet switched network and a mobile station;
receiving event notifications at said packet switched network from
said circuit switched network indicative of a change in the status
of the mobile station; and managing communication resources used
for said packet data communications with the mobile station based
on said event notifications from said circuit switched network.
2. The method of claim 1 wherein the event notification indicates a
presence of the mobile station in the circuit switched network.
3. The method of claim 1 wherein the event notification indicates
that the mobile station has powered down.
4. The method of claim 1 wherein managing communication resources
comprises releasing communication resources used for packet data
communications with said mobile station.
5. The method of claim 4 further comprising notifying an accounting
application accounting for the packet data communications that the
communication resources were released.
6. The method of claim 1 further comprising receiving a request
from said mobile station for circuit services notifications through
said packet-switched network, and invoking a circuit services
notification application responsive to said request to provide
circuit services notifications to said mobile station.
7. An access network for a packet-switched network comprising: a
radio base station supporting packet data communications with a
mobile station; and a controller including a signaling processor
configured to: route circuit services notifications from a circuit
switched network to a mobile station while the mobile station is in
the packet switched network; receive event notifications indicative
of the status of the mobile station from the circuit switched
network; and manage communication resources used for said packet
data communications responsive to said event notifications.
8. The access network of claim 7 wherein the event notifications
comprise a notification message indicating that the mobile station
is present in the circuit switched network.
9. The access network of claim 7 wherein the event notifications
comprise a notification message indicating that the mobile station
has powered down.
10. The access network of claim 7 wherein the signaling processor
is further configured to release communication resources used for
packet data communications with said mobile station responsive to
said event notifications.
11. The access network of claim 10 wherein the signaling processor
is further configured to notify an accounting application
accounting for the packet data communications that the
communication resources were released.
12. A controller for a packet-switched network comprising: a
signaling processor configured to: provide circuit services
notifications to a mobile station; receive an event notification
from the circuit switched network indicative of a change in the
status of the mobile station; and manage communication resources
used for said packet data communications responsive to said event
notification message.
13. The controller of claim 12 wherein the event notification
comprises a notification message indicating that the mobile station
is present in the circuit switched network.
14. The controller of claim 12 wherein the event notification
comprises a notification message indicating that the mobile station
has powered down.
15. The controller of claim 12 wherein the signaling processor is
further configured to release communication resources used for
packet data communications with said mobile station responsive to
said event notification.
16. The controller of claim 15 wherein the signaling processor is
further configured to notify an accounting application accounting
for the packet data communications that the communication resources
were released.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 11/094,951, filed Mar. 31, 2005, which claims priority to
Provisional U.S. Patent Application 60/603,694 filed Aug. 23, 2004
and to Provisional U.S. Patent Application 60/652,585 filed Feb.
14, 2005, and which is incorporated herein by reference in its
entirety.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to the operation of
mobile stations in a hybrid wireless communication network, and
more particularly, to an event notification procedure to make more
efficient use of network resources.
[0003] Cellular networks were originally developed to provide
primarily voice services over circuit switched networks. The
introduction of packet switched 2.5G and 3G networks enables
network operators to provide data services as well as voice
services. Eventually, network architecture is expected to evolve
toward all-IP networks providing both voice and data services.
However, network operators have a substantial investment in
existing infrastructure and would therefore prefer to migrate
gradually to an all-IP network architecture to allow them to
continue to use their existing infrastructure. At the same time,
network operators recognize that there is a demand for high rate
packet-data services. In order to provide high-rate packet data
services, network operators may deploy hybrid networks wherein a
high data rate (HDR) network is overlaid on an existing circuit
switched or packet switched network as a first step in the
transition to an all IP-based network.
[0004] A hybrid network that combines two or more networks with
different signaling protocols and different air interfaces
complicates signaling and session management. One example of a
hybrid network combines an IS2000 radio access network providing
voice and packet data services with a data only network, such as an
IS-856-A High Rate Packet Data (HRPD) access network, providing
high rate packet data services. A mobile station with an active
packet data session in the HRPD access network may need to switch
to the IS2000 network to perform some task, such as answer a voice
call. The mobile station may stop listening to the base station in
the HRPD access network and, under current standards, is not
required to inform the HRPD access network. After switching from
the packet switched network to the circuit switched network, the
mobile station could power down without returning to the packet
switched network. In either scenario, the HRPD access network may
assume that the mobile station is still present and listening, or
that it may return, and consequently reserve resources to serve the
no longer present mobile station. If the HRPD access network
receives incoming packet data for the mobile station, the HRPD
access network may attempt to deliver the data to the mobile
station, which is no longer present. The attempt to deliver the
packet data will fail and the HRPD access network will eventually
deduce that the mobile station is no longer listening. At that
point, the HRPD access network will release resources and update
the packet data serving node for accounting purposes. The packet
switched network may send a request to a Mobile Switching Center
(MSC) to page the mobile station in the IS2000 network before
releasing resources. If the mobile station has powered down, the
attempts to page the mobile station will be futile and will
unnecessarily consume network resources.
SUMMARY OF THE INVENTION
[0005] The present invention provides a method of managing a
communication session with a mobile station in a hybrid network
including a circuit switched network and a packet switched network.
While operating in the packet switched network, the mobile station
may request circuit services notifications through the packet data
network. A mobile switching center (MSC) in the circuit switched
network stores an indication that the mobile station is operating
within the packet switched network and sends circuit services
notifications to the mobile station via the packet switched
network. According to various embodiments of the present invention,
the MSC sends event notifications to the packet switched network
responsive to predetermined events, such as a presence event or a
power down event, indicating a change in the status of the mobile
station. The packet switched network uses the event notifications
to better manage network resources.
[0006] One event that may trigger the event notification procedure
is the presence event. A presence event is an event that indicates
that the mobile station is present in the network. A mobile station
operating in the packet switched network may receive a circuit
services notification, such as a page message, from the circuit
services notification application (CSNA). In this case, the mobile
station may switch to a carrier in the circuit switched network and
send a page response or other message. When the MSC detects the
mobile station in the circuit switched network and the mobile
station has requested forwarding of circuit services notifications
via the packet switched network, the mobile switching center sends
an event notification message to the packet switched network
indicating that the mobile station has been detected. If resources
had been reserved for the mobile station, for example, to support
an active packet data call, the packet switched network can release
those resources, making them available for others to use. Further,
the packet switched network may send an accounting update to a
packet data serving node to update the accounting. Thus, the
present invention facilitates early release of communication
resources, which will increase system throughput and, therefore,
system capacity.
[0007] Another event that may be useful to report is the power down
event. After switching from the packet switched network to the
circuit switched network, the mobile station may power down without
returning to the packet switched network. The packet switched
network may continue to reserve resources, such as A10 connections,
and store information for the mobile station in the event that the
mobile station returns to the packet switched network. In this
scenario, the MSC may send an event notification to the packet
switched network to notify the packet switched network that the
mobile station has powered down. The packet switched network can
then release any resources reserved for the mobile station, such as
A10 connections.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a block diagram of a hybrid network according to
the present invention.
[0009] FIG. 2 is a call flow diagram illustrating an exemplary
scenario using the event notification procedure according to the
present invention.
[0010] FIG. 3 is a flow chart illustrating a procedure executed by
the MSC to implement the session management procedure of the
present invention.
[0011] FIG. 4 is a flow chart illustrating a procedure implemented
by an HRPD access network to implement the session management
procedure according to the present invention.
[0012] FIG. 5 is a flow chart illustrating another procedure
implemented by an HRPD access network to implement the session
management procedure according to the present invention.
[0013] FIG. 6 is a block diagram illustrating exemplary details of
a mobile switching center and HRPD access network.
DETAILED DESCRIPTION OF THE INVENTION
[0014] Referring now to the drawings, the present invention will be
described in the context of a hybrid network 10 providing both
voice and data services to mobile stations 100. In the exemplary
embodiment shown herein, the hybrid network 10 comprises a combined
network incorporating both an IS2000 radio access network (IS2000
RAN) 12 and an HRPD access network (IS856-A) 14. The exemplary
embodiment is intended to be illustrative only and those skilled in
the art will appreciate that the present invention may be used in
networks based on other network standards.
[0015] The IS2000 RAN 12 comprises one or more base stations 24
connected to a circuit switched core network (CSCN) 20. The CSCN 20
provides primarily voice services and low rate data services, such
as facsimile services, to the mobile stations 100. The CSCN 20
includes a mobile switching center (MSC) 22 that provides a
connection to the public switched telephone network (PSTN) 16. The
MSC 22 routes traffic between the PSTN 16 and the base stations 24.
The base stations 24 communicate with the mobile stations 100 over
the air interface. The base stations 24 forward downlink traffic
and signaling from the MSC 22 to the mobile stations 100, and
forward uplink traffic and signaling from the mobile stations 100
to the MSC 22. In some embodiments, the IS2000 may also provide
packet-switched services, though this capability is not material to
the present invention and is not discussed further herein.
[0016] Also shown in FIG. 1 is an HRPD RAN 14. The HRPD RAN 14 is a
high data rate (HDR) network and may be combined with an IS2000
network to provide high speed packet data services. The IS856
standard is generally known as 1xEV-DO. The HRPD RAN 14 comprises
one or more access networks (ANs) 36 for communicating with the
mobile stations 100, and a packet core function (PCF) 34 connecting
the HRPD AN 36 to a packet switched core network (PSCN) 30. The
PSCN 30 includes a PDSN 32 that connects to a packet data network
18, such as the Internet. The PDSN 32 establishes communication
sessions with mobile stations 100 using, for example, the
point-to-point protocol (PPP). The HRPD AN 36 forwards mobile
terminated packet data from the PDSN 32 to the mobile stations 100,
and forwards mobile-originated packet data to the PDSN 32.
[0017] When a mobile station 100 is operating within the IS856
network 14, the mobile station 100 may still want to receive
notifications from the MSC 22 relating to circuit switched services
without having to periodically return to the IS2000 RAN 12 to
receive such notifications. For example, mobile station 100 may
want to receive paging messages over the IS856 air interface
alerting the mobile station 100 to incoming voice calls. To that
end, the HRPD AN 36 includes a 3G1x Circuit Services Notification
Application (CSNA) 42, which may be seen in FIG. 3. Alternatively,
the CSNA 42 could be located in the PCF 34. The CSNA 42 provides
circuit services notifications to mobile stations 100 over the
IS856-A air interface. The CSNA 42 uses the Circuit Services
Notification (CSN) protocol. The CSN protocol also ensures that the
mobile station 100 stays registered with the CSCN 20 even when it
is monitoring the IS856 packet data channel. The CSNA 42 is
described in cdma2000 High Rate packet Data Air Interface
Specification, 3GPP2 C.20024-A, Version 1.0 (March 2004), which is
incorporated herein by reference. The mobile station 100 may
request circuit services notifications from the HRPD RAN 14,
causing the CSNA 42 to notify the MSC 22 to send notification
messages to the mobile station 100 via the HRPD RAN 14. The CSNA 42
and mobile station 100 may configure a filter that allows
notifications associated with only certain circuit switched
services to be sent over the IS856 air interface.
[0018] When the mobile station 100 requests circuit services
notifications from the IS856 network, the MSC 22 will be informed
that the mobile station 100 has requested CSNA services and will
send circuit services notifications to the mobile station 100 via
the HRPD AN 36. The CSNA 42 in the HRPD AN 36 receives the circuit
services messages from the MSC 22, and the CSNA 42 in turn provides
circuit service notifications to the mobile station 100.
[0019] In some scenarios, the circuit services notification sent to
the mobile station 100 may cause the mobile station 100 to
transition to the IS2000 RAN 12. As one example, the CSNA 42 may
receive a paging request message from the MSC 22 and send a page
message to the mobile station 100 responsive to the paging request
message causing the mobile station 100 to transition to the IS2000
RAN 12 to receive a voice call. In other scenarios, the mobile
station 100 may autonomously transition to the IS2000 RAN 12. For
example, the mobile station 100 may transition to the IS2000 RAN 12
to originate a voice call.
[0020] Under the current IS856 standards, the mobile station 100 is
not required to notify the HRPD AN 36 when it transitions to the
IS2000 RAN 12. If the mobile station 100 is engaged in an active
packet data session, the HRPD AN 36 will continue to reserve radio
resources for the active packet data session with the mobile
station 100. The PDSN 32 will forward packet data to the HRPD AN
36, which will attempt to deliver the packet data to the mobile
station 100. The HRPD AN 36, through the use of internal mechanisms
such as inactivity timers, failed delivery attempts, etc., will
eventually determine that the mobile station 100 is not longer
listening on the IS856 carriers and will release the radio and
communication resources that have been reserved for the mobile
station 100. The HRPD AN 36 may request the MSC to page the mobile
station in the IS2000 RAN 12 and wait for a response from the
mobile station 100 before releasing resources.
[0021] When the mobile station 100 transitions from the HRPD RAN 14
to the IS2000 RAN 12, the radio and communications resources
reserved for the mobile station 100 are not being used. Releasing
reserved radio and communication resources as early as possible
would improve overall throughput of the network, and therefore,
increase system capacity. Further, releasing resources when the
mobile station 100 transitions to the IS2000 network can reduce
accounting discrepancies.
[0022] According to the present invention, a method is provided for
sending event notifications between the IS2000 RAN 12 and the HRPD
RAN 14 to more efficiently manage resources. When the mobile
station 100 registers with the HRPD RAN 14, it may request
forwarding of circuit services notifications through the HRPD RAN
14. When the HRPD AN 36 receives a request for circuit services
notifications via the HRPD RAN 14, it notifies the MSC 22 via an A1
signaling link 38 that the mobile station 100 is operating within
the IS 856 RAN 14. The MSC 22 stores an indication, referred to
herein as the forwarding flag, indicating that the mobile station
100 is operating within the HRPD RAN 14. This flag indicates that
circuit services notifications should be forwarded to the mobile
station 100 through the HRPD RAN 14. The forwarding flag is also
used to determine when event notifications should be sent by the
MSC 22 to the HRPD RAN 14. When the forwarding flag is set, the MSC
22 sends event notifications to the HRPD RAN 14 responsive to
certain predetermined events.
[0023] One event that may trigger an event notification is a
presence event. A presence event occurs when the IS2000 RAN 12
detects the mobile station 100 after the mobile station 100 has
transitioned from the HRPD RAN 14. When the MSC 22 detects the
presence of a mobile station 100 after it has transitioned to the
IS2000 RAN 12, the MSC 22 sends an event notification to the HRPD
RAN 14. This situation may occur for example when the mobile
station 100 involved in an active packet data session in the HRPD
RAN 14 receives a circuit services notification, such as a page
message. Responsive to the page message or other circuit services
notification, the mobile station 100 transitions to the IS2000 RAN
12. The mobile station 100 could also transition to the IS2000 RAN
12 on its own initiative, for example, to initiate a voice call.
When the MSC 22 detects that the mobile station 100 has
transitioned to the IS2000 RAN 12 and the forwarding flag is set,
the MSC 22 sends an event notification message to the HRPD RAN 14
to notify the HRPD RAN 14 of the presence event. Upon receipt of
the notification message from the MSC 22, the HRPD RAN 14 can
release resources reserved for the mobile station 100 and send an
accounting update to the PDSN 32 to update accounting. In one
exemplary embodiment, the HRPD RAN 14 places the packet data
session in a dormant state responsive to the event notification.
Thus, the HRPD RAN 14 may tear down its A8 connection and release
any air interface resources reserved for the mobile station while
maintaining the A10 connection to the PDSN 32.
[0024] Another event that may trigger an event notification is
referred to herein as the power down event. If the mobile station
100 powers down after transitioning to the IS2000 RAN 12, the MSC
22 may send an event notification to the HRPD RAN 14 to notify that
the mobile station 100 is no longer reachable. In response to the
power down event notification, the HRPD RAN 14 terminates the
packet data session and tear down the A10 connection to the PDSN
32. Similarly, the HRPD RAN 14 may send an event notification to
the IS2000 RAN 12 when the mobile station 100 powers down while
present in the HRPD RAN 14.
[0025] FIG. 2 is a call flow diagram illustrating how event
notifications may be used. The call flow diagram is meant to be
illustrative. Those skilled in the art will recognize that the
present invention may be implemented in other procedures. The
mobile station 100 establishes an active packet data call with the
HRPD RAN 14 (step a). It is assumed that the mobile station 100 has
requested CSNA services and that the MSC 22 has set the forwarding
flag as previously described. While the mobile station 100 is
involved in an active packet data call, the MSC 22 sends an A1
paging request to F the HRPD AN 36 (step b), and the HRPD AN 36
sends an IS2000 page message to the mobile station 100 encapsulated
within a IS856-A air interface message (step c). The mobile station
100 transitions to the IS2000 RAN 12 and sends an IS2000 page
response encapsulated within a IS856-A air interface message (step
d). The IS2000 BS 24 receives the page response from the mobile
station 100, reformats the page response, and sends an A1 paging
response to the MSC 22 (step e). The MSC 22 sends an event
notification to the HRPD AN 36 indicating that the mobile station
100 has been detected in the IS2000 RAN 12 (step f). The HRPD RAN
14 stops its inactivity timer and releases radio and communication
resources assigned to the mobile station 100. The HRPD AN 36 also
sends an accounting update to the PDSN 32 to update accounting for
the packet data call (step g). At this point, the packet data call
goes into a dormant state (step h). In the dormant state, the HRPD
RAN 14 maintains a connection with the PDSN 32 for the packet data
call but there is no communication channel established between the
HRPD RAN 14 and the mobile station 100. As is well known to those
skilled in the art, the communication channel for the packet data
call can be re-established at the initiative of either the HRPD RAN
14 or the mobile station 100. Procedures for re-establishing the
packet data calls are not material to the present invention.
[0026] The mobile station 100 powers down without returning to the
HRPD RAN 14. Before shutting down, the mobile station 100 and MSC
22 execute a power down procedure (step i). In one exemplary
procedure, the mobile station 100 sends a power down indication to
the IS2000 BS 24, which in turn sends a Clear Request message to
the MSC 22 to initiate call clearing. The MSC 22 sends a Clear
Command message to the IS2000 BS 24, which releases the resources
allocated to the mobile station and sends a Clear Complete message
with a power down indicator to the MSC 22. In response to the Clear
Complete message, the MSC 22 sends an event notification to the
HRPD RAN 14 (step j) and the HRPD RAN 14 terminates the packet data
session and releases the A10 connection to the PDSN 32.
[0027] FIG. 3 is a flow diagram illustrating an exemplary
notification procedure 60 implemented by the MSC 22. The procedure
60 begins when the MSC 22 receives a request from the HRPD RAN 14
to send circuit services notifications to the mobile station 100
via the HRPD AN 36 (block 62). The MSC 22 sets a forwarding flag to
true (block 64). When the MSC 22 subsequently detects an event
(block 66), it determines the setting of the forwarding flag (block
68). The detected event may, for example comprises a presence
event, power down event, or some other event. If the forwarding
flag is set to true, the MSC 22 sends the HRPD RAN 14 an event
notification (block 70). The event notification includes an
indication of the type of the event. The MSC 22 responds to the
event normally as specified in applicable standards (block 72) and
the process ends (block 74). If the forwarding flag is set to false
(block 68), the MSC 22 processes the received message from the
mobile station 100 normally (block 72).
[0028] FIG. 4 illustrates an exemplary resource management
procedure 80 implemented by an HRPD RAN 14 for responding to a
presence event. It is assumed that the mobile station 100 has
requested CSNA services and that the presence flag at the HRPD AN
36 is set to true. The procedure begins when the HRPD AN 36
receives a notification that the mobile station 100 has been
detected in the IS2000 RAN 12 (block 82). The HRPD AN 36 determines
if a packet data call is active (block 84). If so, the HRPD AN 36
stops its internal inactivity timer (block 86) and releases
resources assigned to the mobile station 100 (block 88).
Additionally, the HRPD AN 36 sends an accounting update to the PDSN
32 (block 90) and sets a presence flag equal to false (block 92).
The presence flag indicates whether the mobile station 100 is
present and listening in the HRPD AN 36. The HRPD AN 36 can use the
presence flag to determine if it should attempt delivery of packet
data over the IS856 air interface, or send a request to the MSC 22
to page the mobile station 100. The HRPD AN 36 sets the presence
flag to false (block 92) and the procedure ends (block 94).
[0029] FIG. 5 illustrates an exemplary procedure 110 implemented by
the HRPD AN 36 for responding to a power down event. The procedure
begins when the HRPD AN 36 receives an event notification from the
MSC 22 indicating that the mobile station 100 has powered down
(block 112). The HRPD AN 36 determines if a packet data call
session exists (block 114). If so, the HRPD AN 36 terminates the
packet data session (block 116), tears down the A10 connection to
the PDSN 32, and releases radio resources (block 118).
Additionally, the HRPD AN 36 may send an accounting update to the
PDSN 32 (block 120) and the procedure ends (block 122).
[0030] FIG. 6 illustrates an exemplary MSC 22 and HRPD AN 36 in
more detail. The MSC 22 includes a call control and mobility
management circuit 46 for call control handling and mobility
management functions, and a switch 48 for routing user traffic. The
AN 36 includes a controller 40 and one or more sectors 44. The
sectors 44 contain the radio equipment for communicating with the
mobile stations 100. The controller 40 comprises the control
portion of the AN 36. The controller 40 processes call control
signaling and manages the radio and communication resources used by
the sectors 44. The controller 40 includes the CSNA 42, which may
be implemented in a processor programmed to carry out the functions
of the CSNA 42. The CSNA 42 exchanges signaling with the MSC 22 and
provides the circuit services notifications to mobile stations 100
over the IS856 air interface. Signaling traffic between the
controller 40 and the MSC 22 is carried over the A1 interface. The
A8 and A9 interfaces carry user traffic and signaling,
respectively, between the HRPD AN 36 and PCF 34. The A13 interface
transfers user traffic and signaling between HRPD ANs 36.
[0031] In any case, those skilled in the art should appreciate that
the present invention is not limited by the foregoing discussion,
nor by the accompanying figures. Rather, the present invention is
limited only by the following claims and their reasonable legal
equivalents.
* * * * *