U.S. patent application number 11/426395 was filed with the patent office on 2006-10-19 for wireless router and method for processing traffic in a wireless communications network.
This patent application is currently assigned to Cisco Technology, Inc.. Invention is credited to Mohammad R. Ali, Ojas T. Choksi, Ramanamurthy Dantu, Balajl S. Holur, Jerzy Miernik, Achal R. Patel, Pulin R. Patel.
Application Number | 20060233137 11/426395 |
Document ID | / |
Family ID | 36600529 |
Filed Date | 2006-10-19 |
United States Patent
Application |
20060233137 |
Kind Code |
A1 |
Dantu; Ramanamurthy ; et
al. |
October 19, 2006 |
Wireless Router and Method for Processing Traffic in a Wireless
Communications Network
Abstract
A wireless communications network includes a wireless-specific
router topology layer that connects cellular sites to a wireline
topology. The wireless-specific router topology provides a
distributed architecture in which call processing including call
setup, resource preservation, air bandwidth allocation, switching,
soft handoff, and micromobility is performed at the cell level. The
wireless routers are technology independent to support various
cellular technologies. The wireless router may include a first
interface operable to communicate wireless packets for a call with
a remote device and a second interface operable to communicate
wireline packets for the call with the wireline network. A traffic
controller is coupled to the first and second interfaces and
operable to convert traffic between the wireless and wireline
packets and to route packets to a destination mobile or wireline
device. A selection and distribution unit is operable to select and
distribute traffic to support soft handoff for calls in the
wireless communications network.
Inventors: |
Dantu; Ramanamurthy;
(Richardson, TX) ; Patel; Pulin R.; (McKinney,
TX) ; Choksi; Ojas T.; (Plano, TX) ; Patel;
Achal R.; (McKinney, TX) ; Ali; Mohammad R.;
(Plano, TX) ; Miernik; Jerzy; (Allen, TX) ;
Holur; Balajl S.; (Plano, TX) |
Correspondence
Address: |
BAKER BOTTS L.L.P.
2001 ROSS AVENUE
SUITE 600
DALLAS
TX
75201-2980
US
|
Assignee: |
Cisco Technology, Inc.
San Jose
CA
|
Family ID: |
36600529 |
Appl. No.: |
11/426395 |
Filed: |
June 26, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09513914 |
Feb 25, 2000 |
7068624 |
|
|
11426395 |
Jun 26, 2006 |
|
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Current U.S.
Class: |
370/331 ;
370/392 |
Current CPC
Class: |
H04L 45/50 20130101;
H04W 40/248 20130101; H04L 45/54 20130101; H04L 47/724 20130101;
H04L 47/70 20130101; H04L 47/824 20130101; H04W 28/02 20130101;
H04L 45/56 20130101; H04L 47/14 20130101; H04L 47/825 20130101;
H04L 45/52 20130101; H04L 47/767 20130101 |
Class at
Publication: |
370/331 ;
370/392 |
International
Class: |
H04Q 7/00 20060101
H04Q007/00; H04L 12/56 20060101 H04L012/56 |
Claims
1. A wireless communications network, comprising: a first wireless
router; a second wireless router; a first wireless virtual path
configured for a call between the first and second routers for
transmission of wireline protocol traffic; and a second wireless
virtual path configured for the call between the first and second
routers for transmission of wireless protocol traffic, the first
and second wireless virtual paths each comprising a multi-protocol
label switched path (MPLS), the wireline protocol traffic and the
wireless protocol traffic including labels generated upon receipt
of the wireline protocol traffic and the wireless protocol traffic
for routing over the first and second wireless virtual paths to
facilitate soft handoff of a call.
2. The wireless communications network of claim 1, wherein the
first and second wireless routers are operable to intercommunicate
over the second wireless virtual path to provide a soft handoff for
a call.
3. The wireless communications network of claim 1, wherein the
first and second wireless routers are operable to intercommunicate
to allocate bandwidth for a call.
4. The wireless communications network of claim 1, wherein the
first and second wireless routers are operable to intercommunicate
to reserve resources for a call.
5. The wireless communications network of claim 1, wherein the
first and second wireless routers are operable to intercommunicate
to provide mobility management for a call.
6. The wireless communications network of claim 1, further
comprising: a set of active wireless routers for a call, the set
including the first and second routers; and the set of routers
operable to intercommunicate over wireless virtual paths to provide
a plurality of call mobility, soft handoff, and resource management
for the call.
7. A communications signal transmitted on a wireline link, the
communication signal comprising: a payload including one of
wireless protocol and wireline protocol traffic for a call with a
mobile device; and a virtual path label generated upon receipt of
the payload for the call for routing the payload over a wireless
virtual path associated with one of the wireless protocol traffic
and the wireline protocol traffic established for the call to a
wireless router for call processing, the virtual path label
comprising a multi-protocol label switch (MPLS) path label.
8. The communications signal of claim 7, wherein the payload is
generated by the mobile device.
9. The communication signal of claim 7, further comprising: a
synchronization bias for the payload.
10. The communications signal of claim 7, wherein the virtual path
label identifies a primary router for the call.
11. A wireless router for communicating signals in a wireless
network, the wireless router comprising: a radio frequency (RF)
front end operable to receive a first signal from a mobile device
and generate a label associated with the first signal; a selection
and distribution unit coupled to the RF front end, the selection
and distribution unit operable to receive the first signal, to
receive a second signal corresponding to the first signal from a
disparate wireless router transmitted over a first wireless virtual
path for wireless protocol traffic established according to the
first signal in accordance with a label generated by the disparate
wireless router and associated with the second signal, and to
select one of the first signal and the second signal; and a
resource manager coupled to the selection and distribution unit,
the resource manager operable to communicate the selected signal to
a wireline network, wherein the wireless router is a first wireless
router, and wherein the selection and distribution unit comprises a
label switched path (LSP) module operable to define the first
wireless virtual path for the wireless protocol traffic from the
first wireless router to the disparate wireless router, the LSP
module of the selection and distribution unit operable to define a
second wireless virtual path for wireline protocol traffic
associated with the wireless protocol traffic from the first
wireless router to the disparate wireless router.
12. The wireless router of claim 11, wherein the selection and
distribution unit is operable to define the first and second
wireless virtual paths using a forwarding table.
13. The wireless router of claim 11, wherein the selection and
distribution unit is operable to define the first and second
wireless virtual paths using a trigger rule.
14. The wireless router of claim 11, wherein the selection and
distribution unit is operable to select one of the first signal and
the second signal using pattern matching on a frame-by-frame
basis.
15. The wireless router of claim 11, wherein the selection and
distribution unit is operable to select one of the first signal and
the second signal using error correction bits.
16. The wireless router of claim 11, wherein the selection and
distribution unit is operable to synchronize the first signal and
the second signal using a frame sequence number (FSN) in each of
the signals.
17. The wireless router of claim 11, further comprising: an active
list comprising at least one cell site with which the mobile device
is actively communicating.
18. The wireless router of claim 11, further comprising: a
candidate list comprising at least one cell site with which the
mobile device is operable to communicate.
19. The wireless router of claim 11, further comprising: an antenna
coupled to the RF front end and operable to receive the first
signal from the mobile device and to communicate the first signal
to the RF front end.
20. A method for configuring a wireless communications network for
processing a call, comprising: receiving a communication from a
mobile device identifying an active set of wireless routers for a
call, the active set of wireless routers including a primary
wireless router and one or more secondary wireless routers for soft
handoff of the call; informing the primary and secondary wireless
routers of their status; configuring wireless virtual paths for
wireless protocol traffic and wireline protocol traffic for the
call between the primary and secondary wireless routers; and
allocating resources in the primary and secondary wireless routers
for the call, wherein the wireless virtual paths are label switch
paths (LSPs); forwarding information associated with the call
between the primary and secondary wireless routers over the
wireless virtual paths, the information including labels generated
upon receipt for routing over the wireless virtual paths to
facilitate the soft handoff of the call.
21. The method of claim 20, wherein the wireless virtual paths
comprise radio frame virtual paths.
22. The method of claim 20, wherein the wireless virtual paths
comprise LSPs transporting at least one of CDMA, CDMA 2000, WCDMA,
TDMA and GSM radio frames.
23. A method for providing soft handoff for a call including a
mobile device, comprising: receiving an instance of a radio frame
from a mobile device at an active set of wireless routers, the
active set including a plurality of active wireless routers for a
call; assigning a label to each instance of the radio frame at each
of the plurality of active wireless routers; establishing at least
a first wireless virtual path for carrying wireline protocol
traffic and a second wireless virtual path for carrying wireless
protocol traffic between the primary wireless router and secondary
wireless routers; routing the radio frame instances from secondary
wireless routers in the active set to a primary wireless router in
the active set over a wireless virtual path established for the
call by the primary wireless router to the secondary wireless
routers in accordance with the labels; and selecting at the primary
wireless router one of the radio frame instances for transmission
to a destination device, wherein the radio frames are routed from
the secondary wireless routers to the primary wireless router over
the wireless virtual paths through label switched paths (LSPs)
established between the primary and the secondary wireless
routers.
24. The method of claim 23, further comprising: assembling the
selected radio frame instance with other selected radio frame
instances to form an Internet protocol (IP) packet; and
transmitting the IP packet to the destination device.
25. The method of claim 23, wherein the radio frames received at
the primary wireless router from the mobile device are routed to
the secondary wireless routers through the wireless virtual
path.
26. The method of claim 23, wherein the radio frames are routed
from the secondary wireless routers to the primary wireless router
through virtual paths established between the primary and the
secondary wireless routers.
27. The method of claim 23, further comprising: receiving traffic
from the destination device at the primary wireless router;
assigning a label to each instance of the traffic at the primary
wireless router; multicasting instances of the traffic from the
primary wireless router to each of the secondary wireless routers
in the active set of wireless routers over the wireless virtual
paths established for the call in accordance with the labels; and
transmitting instances of the traffic to the mobile device from
each of the wireless routers in the active set.
28. The method of claim 27, further comprising synchronously
transmitting instances of the traffic from the wireless routers in
the active set to the mobile device.
29. The method of claim 27, wherein the traffic comprises an
Internet protocol (IP) packet, further comprising: segmenting the
IP packet into a plurality of radio frames at the primary wireless
router; assigning a label to each radio frame; multicasting
instances of each radio frame to the secondary wireless routers in
the active set of wireless routers over the wireless virtual paths
established for the call in accordance with the labels; and
transmitting instances of the radio frame to the mobile device from
each of the wireless routers in the active set.
30. The method of claim 27, further comprising transmitting at
least one instance of the traffic from the primary wireless router
to a secondary wireless router with a synchronization bias operable
to delay transmission of the instance from the secondary wireless
router to the mobile device.
31. A method for providing mobility for mobile devices in a
wireless communications network, comprising: providing a network
anchor wireless router; providing a primary wireless router
receiving traffic from a mobile device for a call and forwarding
the traffic to the network anchor wireless router through a
wireless virtual path carrying wireless protocol traffic
established for the call by the primary wireless router for
delivery to a destination device, the primary wireless router
assigning labels to the traffic to facilitate routing to the
network anchor wireless router over the wireless virtual path; the
network anchor wireless router receiving traffic from the
destination device and forwarding the traffic to the primary
wireless router through a wireless virtual path carrying wireline
protocol traffic established for the call by the primary wireless
router for delivery to the mobile device, the network anchor
wireless router assigning labels to the traffic to facilitate
routing to the primary wireless router over the wireless virtual
path; receiving a new primary wireless router; terminating the
existing wireless virtual path between the network anchor and
primary wireless router; and establishing a new wireless virtual
path for the call between the network anchor wireless router and
the new wireless router for communication of traffic for the call,
wherein the virtual paths comprise label switch paths (LSPs).
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 09/513,914 filed Feb. 25, 2000, now U.S. Pat. No. 7,068,024
issued Jun. 27, 2006.
[0002] This application is related to U.S. patent application Ser.
No. 09/513,912 filed Feb. 25, 2000, now U.S. Pat. No. 6,865,185;
U.S. patent application Ser. No. 09/513,913 filed Feb. 25, 2000,
now U.S. Pat. No. 6,522,628; U.S. patent application Ser. No.
09/513,592 filed Feb. 25, 2000, now U.S. Pat. No. 7,043,225; and
U.S. patent application Ser. No. 09/513,090 filed Feb. 25, 2000,
now U.S. Pat. No. 7,031,266, all of which are hereby incorporated
by reference herein.
TECHNICAL FIELD OF THE INVENTION
[0003] The present invention relates generally to the field of
wireless communications and more particularly to a wireless router
and method for processing traffic in a wireless communications
network.
BACKGROUND OF THE INVENTION
[0004] Wireline Internet protocol (IP) provides efficient
connectivity between remote devices. IP networks are implemented
with routers that interconnect physically and logically separate
network segments. In operation, the routers distinguish data
packets according to network protocols and forward traffic
according to network-level addresses utilizing information that the
routers exchange among themselves to find the best path between
network segments. As the status of routers change in the network,
the routers exchange information to reroute traffic around
congested or failed routers or to route traffic to a newly
activated router.
[0005] Cellular and other wireless networks have been connected to
IP networks in order to allow cellular phones and other mobile
devices to communicate with remote devices over the IP network. A
typical cellular network covers a contiguous area that is broken
down into a series of cells. Each cell has a base station that
provides a radio frequency (RF) link for cellular phones within the
cell. As cellular phones move between cells, the calls are handed
off between base stations to provide continuous coverage.
[0006] The base stations are managed by a base station controller
which performs handoffs and other intercell operations. A mobile
switching center is connected to the base station controllers and
switches all traffic in the cellular network. A data interworking
function provides connectivity from the mobile switching center to
the Internet or other data network via circuit switched and packet
switched data protocols.
[0007] Within conventional cellular networks, the mobile switching
centers are vulnerable to overloading during peak traffic times
which may cause traffic to be delayed and/or dropped. In addition,
available bandwidth between the base stations, base station
controllers, and mobile switching centers is unnecessarily used by
redundant messaging between the nodes. Another problem is the
relatively low speed and reliability of call handoffs between
cells.
SUMMARY OF THE INVENTION
[0008] The present invention provides a wireless router and method
for processing traffic in a wireless communications network that
substantially eliminate or reduce the problems and disadvantages
associated with previous methods and systems. In particular,
cellular and other wireless networks are implemented with wireless
routers that provide an all-Internet protocol (IP) access network,
distribute traffic processing functionality to the cells, and
seamlessly interwork with the core IP network.
[0009] In accordance with one embodiment of the present invention,
a wireless router includes a first interface operable to
communicate wireless packets for a call with a mobile device and a
second interface operable to communicate wireline packets for the
call with a wireline network. A traffic controller is operable to
convert wireline packets received for the call from the wireline
network to wireless packets, to route the wireless packets to the
mobile device through the first interface, to convert wireless
packets received from the mobile device to wireline packets, and to
route the wireline packets to the wireline network through the
second interface.
[0010] In accordance with another aspect of the present invention,
a wireless router includes a first interface operable to
communicate traffic for a call with a mobile device and a second
interface operable to communicate traffic for the call with a
wireline network. A virtual path generator is operable to configure
a wireless virtual path in the wireline network to a second
wireless router. A traffic controller is operable to communicate
with the second wireless router through the wireless virtual path
to process traffic for the call.
[0011] More specifically, in accordance with a particular
embodiment of the present invention, the wireless router includes a
selector and a distributor for soft handoff call processing. In
this embodiment, the selector is operable to receive a first
instance of the wireless traffic from the mobile device, to receive
a second instance of the wireless traffic from the second wireless
router, and to select one of the instances for transmission to a
destination device for the call. The distributor is operable to
receive from the wireline network traffic destined for the mobile
device, to transmit a first instance of the traffic to the mobile
device, and to transmit a second instance of the traffic to the
second wireless router for transmission to the mobile device. The
virtual path may be a label switched path (LSP) and the traffic may
be a radio frame.
[0012] In accordance with another aspect of the present invention,
a wireless communications network includes a first and a second
router. A first virtual path is configured between the first and
second routers for transmission of wireline protocol traffic. A
second virtual path is configured between the first and second
routers for transmission of wireless protocol traffic. The first
and second virtual paths may be LSPs, the wireline protocol traffic
may be Internet protocol (IP) traffic and a wireless protocol
traffic may be radio frames.
[0013] In accordance with yet another aspect of the present
invention, a communications signal transmitted on a wireline link
may include a radio frame having traffic for a call including a
mobile device. A virtual path label is appended to the radio frame
for routing the radio frame to a router for call processing. A
virtual path label may be a multi-protocol label switched (MPLS)
path label and may identify a primary router for processing the
call.
[0014] In accordance with yet another aspect of the present
invention, a wireless communications network includes a plurality
of routers. Each router is operable to receive traffic from a
mobile device and to route the traffic directly to an IP wireline
network. The routers may intercommunicate with one another to
establish a call and to reserve resources, allocate bandwidth,
perform soft handoffs, and provide common ability for the call.
[0015] In accordance with yet another aspect of the present
invention, a method and system for configuring a wireless
communications network for processing a call includes receiving a
communication from a mobile device identifying an active set of
wireless routers for a call. The active set of wireless routers
includes a primary wireless router and one or more secondary
wireless routers for soft handoff of the call. The primary and
secondary wireless routers are informed of their status. Virtual
paths are configured between the primary and secondary wireless
routers. Resources in the primary and secondary wireless routers
are allocated for the call.
[0016] In accordance with still another aspect of the present
invention, a method and system for providing mobility management
for mobile devices in a wireless communications network includes
providing an active set of wireless routers including an existing
primary wireless router and a plurality of existing secondary
wireless routers for performing soft handoff for a call. A new
active set of wireless routers is received. The new active set
identifies a new primary wireless router and a plurality of new
secondary wireless routers. Existing virtual paths between the
existing primary wireless router and the existing secondary
wireless routers are terminated. Virtual paths between the new
primary wireless router and the new secondary wireless routers are
established. A network destination device of the call is informed
of the new primary wireless router. Traffic for the call is queued
at the new primary wireless router until traffic previously queued
in the existing wireless router is processed.
[0017] Technical advantages of the present invention include
providing a wireless router for a wireless communications network.
The wireless router allows intelligence and call switching and
control functionality to be distributed to the cell sites. As a
result, transmission resources are efficiently used and common
switching points that can lead to delayed and/or dropped traffic
are reduced or eliminated.
[0018] Another technical advantage of the present invention
includes providing a technology independent wireless network
architecture. In particular, the wireless routers provide a
simplified all IP wireless access network that seamlessly
interworks with the core IP network. The wireless routers may each
be provisioned to support any one of a number of wireless access
technologies. As a result, new services and features may be readily
provisioned in a wireless network and new technologies
supported.
[0019] Yet another technical advantage of the present invention
includes providing a distributed architecture for a wireless access
network. In particular, call processing functionality is
distributed to the base station or cell site level. Call set-up,
resource reservation, air bandwidth allocation and switching
functions are performed at the cell sites. As a result, traffic may
be efficiently processed at the cell sites and centralized
choke-points in the wireless network are reduced or eliminated. In
addition, the distributed system requires fewer components which
reduces system and maintenance costs and increase reliability.
[0020] Yet another technical advantage of the present invention
includes providing an improved method and system for performing
handoffs in a wireless network. In particular, the wireless routers
set up MPLS or other virtual paths on a per call basis to perform
traffic selection and distribution for soft handoffs. The MPLS
paths improve the speed and efficiency of soft handoff operations
in the wireless network.
[0021] Still another technical advantage of the present invention
includes providing an improved micro mobility method and system
within a wireless communications network. In particular, the
wireless routers communicate among themselves as a mobile device
transitions between cells to transfer call processing functionality
between the routers and to reconfigure the MPLS paths. As a result,
mobility management is distributed to and efficiently handled at
the cell sites.
[0022] Other technical advantages will be readily apparent to one
skilled in the art from the following figures, description, and
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] For a more complete understanding of the present invention
and its advantages, reference is now made to the following
description, taken in conjunction with the accompanying drawings,
in which:
[0024] FIG. 1 is a block diagram illustrating layers of an all
Internet protocol (IP) wireless communications network in
accordance with one embodiment of the present invention;
[0025] FIG. 2 is a block diagram illustrating connection of the
wireless router network of FIG. 1 to traffic and control interfaces
in accordance with one embodiment of the present invention;
[0026] FIG. 3 is a block diagram illustrating details of the
communication paths between the wireless routers of FIG. 1 in
accordance with one embodiment of the present invention;
[0027] FIGS. 4A-C are a series of block diagrams illustrating
protocol stacks for the mobile device, wireless router, and
wireline router of FIG. 1 in accordance with one embodiment of the
present invention;
[0028] FIGS. 5A-B are a series of block diagrams illustrating data
packets transmitted in the multi-protocol label switch (MPLS) paths
of FIG. 3 in accordance with one embodiment of the present
invention;
[0029] FIG. 6 is a block diagram illustrating details of the
wireless router of FIG. 1 in accordance with one embodiment of the
present invention;
[0030] FIG. 7 is a block diagram illustrating details of the
quality of service (QoS) engine of FIG. 6 in accordance with one
embodiment of the present invention;
[0031] FIG. 8 is a block diagram illustrating details of the
traffic processing tables of FIG. 6 in accordance with one
embodiment of the present invention;
[0032] FIG. 9 is a block diagram illustrating details of the IP
forwarding table of FIG. 8 in accordance with one embodiment of the
present invention;
[0033] FIG. 10 is a block diagram illustrating details of the MPLS
tunnel table of FIG. 8 in accordance with one embodiment of the
present invention;
[0034] FIG. 11 is a block diagram illustrating details of the
outgoing LSP table of FIG. 8 in accordance with one embodiment of
the present invention;
[0035] FIG. 12 is a block diagram illustrating details of the
incoming LSP table of FIG. 8 in accordance with one embodiment of
the present invention;
[0036] FIG. 13 is a block diagram illustrating details of the soft
handoff bandwidth availability table of FIG. 8 in accordance with
one embodiment of the present invention;
[0037] FIG. 14 is a flow diagram illustrating a method for
configuring the wireless routers of FIG. 1 for call processing in
accordance with one embodiment of the present invention;
[0038] FIG. 15 is a block diagram illustrating soft handoff and
micro mobility for a call in an exemplary wireless communications
network;
[0039] FIG. 16 is a flow diagram illustrating a method for
selecting ingress wireless traffic from an active set of wireless
routers for soft handoff of a call in accordance with one
embodiment of the present invention;
[0040] FIG. 17 is a flow diagram illustrating a method for
distributing egress wireless traffic between an active set of
wireless routers for soft handoff of a call in accordance with one
embodiment of the present invention;
[0041] FIG. 18 is a block diagram illustrating delay biasing of
egress wireless traffic for soft handoff of a call in an exemplary
wireless communications network;
[0042] FIG. 19 is a block diagram illustrating soft handoff
functionality of the wireless router of FIG. 6 in accordance with
one embodiment of the present invention; and
[0043] FIG. 20 is a flow diagram illustrating a method for managing
mobility of wireless devices between the wireless routers of FIG. 2
in accordance with one embodiment of the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0044] FIG. 1 illustrates a wireless communications network 10 in
accordance with one embodiment of the present invention. In this
embodiment, the wireless network 10 is a multiple layer cellular
network in which terrestrial wireless transmission originates in
geographically delimited cells. It will be understood that the
present invention may be used in connection with other suitable
wireless networks.
[0045] Referring to FIG. 1, the wireless network 10 includes a
service layer 12, a control layer 13, a wireline router layer 14, a
wireless router layer 16, and a physical layer 18. The service
layer 12 provides network services such as call server, bandwidth
broker, policy server, service level agreement (SLA) manager,
billing server, home location register (HLR), home subscriber
server (HSS), domain name server (DNS), dynamic host configuration
protocol (DHCP), media gateway (MGW), signaling gateway (SGW),
legacy servers such as mobile switching center (MSC), base station
controller (BSC), and serving GPRS serving node (SGSN), voicemail
server (VMS), fax/modem server, short message center (SMSC),
conferencing facilities, transcoders, and other suitable services.
The control layer 13 provides a quality of service (QoS) manager,
mobility manager, location manager, call agent, media gateway
controller (MGC), power manager, authentication, authorization, and
accounting (AAA), and other suitable agents and managers.
[0046] The wireline router layer 14 may be a wireline specific
Internet protocol (IP) layer. The wireline router layer 14 includes
a wireline router network having a plurality of wireline routers 20
interconnected by physical wireline links 22. The wireline routers
20 receive and transmit traffic on the wireline links 22. The
wireline router network forms the core IP network and may be the
Internet, intranet, extranet, or other suitable local, wide area
network, or combination of networks.
[0047] The wireless router layer 16 may be a wireless-specific IP
layer. The wireless router layer 16 includes a wireless router
network having a plurality of wireless routers 30 interconnected by
wireless router links 32. The wireless router links 32 may be
microwave or other wireless links or virtual or other suitable
flows configured in the wireline links 22 of the wireline IP layer
14. Each wireless router 30 may be implemented as a discrete node
independent of a wireline router 20 or may be implemented as a
logical layer in a wireline router 20.
[0048] The wireless routers 30 intercommunicate traffic and control
information over the wireless router links to perform call set up,
resource reservation, mobility management, soft handoff, air
bandwidth allocation and routing. As described in more detail
below, the wireless router links 32 may comprise multi-protocol
label switch (MPLS) or other suitable virtual tunnels formed in the
wireline links 22. The wireless routers 30 may be self-configuring
as described in co-owned U.S. Patent Application entitled "Method
and System for Configuring Wireless Router and Network," previously
incorporated by reference.
[0049] The wireless routers 30 are connected to the wireline
routers 20 by wireline links. In this way, the wireless routers 30
provide connectivity from the wireless portion of the network 10 to
the wireline portion of the network 10 via circuit switched and
packet switched data protocols. Thus, the wireless routers 30
receive and route traffic over both wireline and wireless links 22
and 32.
[0050] The physical layer 18 includes a series of overlapping cells
40. Each cell 40 is supported by a corresponding wireless router 30
and may be subdivided into a plurality of geo-location areas 42.
The geo-location areas 42 are each a defined area in which
bandwidth may be allocated to mobile devices 44. Further
information regarding the geo-location areas and allocation of
bandwidth within geo-location areas is described in co-owned U.S.
patent application Ser. No. 09/466,308, entitled "Method and System
for Allocating Bandwidth in a Wireless Communications Network,"
filed Dec. 17, 1999, which is hereby incorporated by reference.
[0051] In the wireless network 10, each wireless router 30 provides
a radio frequency (RF) link for mobile devices 44 within a
corresponding cell 40. The wireless RF link to the mobile devices
44 in the cell 40 may be based on established technologies, or
standards such as IS-54 (TDMA), IS-95 (CDMA), GMS and AMPS, 802.11
based WLAN, or new upcoming technologies such as CDMA 2000 and
W-CDMA or proprietary radio interfaces. The mobile devices 44 may
be cell phones, data phones, data devices, portable computers, or
any other suitable device capable of communicating information over
a wireless link.
[0052] Due to the nature of the RF airlink, the interference
generated by the usage of various mobile devices 44 is
inter-dependent. That is, the interference generated by the usage
of a mobile device 44 including transmitting and receiving signals
is not only dependent on its geo-location, but is also dependent on
the geo-location of surrounding mobile devices 44 and the usage of
those devices. Thus, the cellular network is an inherently
interference-limited network with bandwidth usage in a particular
location impacting the interference in specific areas of the
neighborhood. In complete spectrum sharing systems such as CDMA and
W-CDMA, bandwidth usage in a particular area directly impacts the
bandwidth available at different locations in the neighborhood.
[0053] In operation, the wireless routers 30 each have a defined
bandwidth with which to communicate with the mobile devices 44 in
the cells 40. The bandwidth is used by the wireless router 30 and
the mobile devices 44 to communicate voice and data information.
The supported bandwidth is a function of various factors such as
frequency reuse, carrier to interface ratio, bit-energy to noise
ratio, effective bit-rate per connection and the like. The
bandwidth available to allocate to certain flows is geo-location
dependent, and time dependent based on current usage of other flows
in the geo-neighborhood.
[0054] The wireless routers 30 each allocate bandwidth within a
corresponding cell 40, route traffic to and from the cell 40, and
track the location of the mobile devices 44 within the cell 40. The
position of a mobile device 44 may be determined using
network-assist, global position systems (GPS) and radio frequency
fingerprinting. Preferably, the positioning technique provides fast
and accurate information with respect to the location of the mobile
device 44 to minimize acquisition time for position
information.
[0055] As mobile users move from cell 40 to cell 40, the wireless
routers 30 perform soft handoff operations to provide continuous
connectivity within the network. As described in more detail below,
the wireless routers 30 provide additional call control and
switching functionality to provide an all-IP wireless access
network with seamless interworking with core IP network elements in
a distributed control architecture. As a result, transmission
resources are efficiently used and choke-points in the system are
reduced or eliminated. In addition, the all-IP architecture is
technology independent which allows routers 30 to be provisioned to
support one of a number of wireless access technologies. New
service and features may be readily provisioned to the wireless
routers 30 and new technologies supported.
[0056] FIG. 2 illustrates connection of the wireless router network
to service gateways in accordance with one embodiment of the
present invention. In this embodiment, the wireless router network
is directly connected to the gateways. It will be understood that
the wireless router network may be connected to one or more of the
gateways through the core IP network. Thus, the gateways may be
remote or local to the wireless routers 30.
[0057] Referring to FIG. 2, a media gateway 50 connects the
wireless routers 30 to a public switched telephone network (PSTN)
52. A legacy gateway 54 connects the wireless routers 30 to a G2/G3
or other legacy cellular network 56. The legacy cellular network 56
includes a mobile switching center (MSC) 60 providing switching
functionality for a plurality of base station controllers (BSC) 62
that each control a plurality of base stations (BS) 64. The
gateways 50 and 54 allow the wireless routers 30 to communicate
traffic between a mobile device 44 in a corresponding cell 40 and a
wireline phone in the PSTN 52 or mobile device in the legacy
cellular network 56.
[0058] FIG. 3 illustrates details of the wireless router links 32
and the control link between the wireless routers 30 and the
traffic and control interfaces in accordance with one embodiment of
the present invention. In this embodiment, the wireless routers 30
communicate with each other through virtual paths, or circuits
configured in the wireline links 22. It will be understood that the
wireless routers 30 may otherwise suitably communicate with one
another through IP or other flows in the wireline or other suitable
links.
[0059] Referring to FIG. 3, the wireless router links 32 include a
wireline specific virtual tunnel, or path 70 and a wireless
specific virtual tunnel, or path 72. The wireline virtual tunnel 70
transports wireline protocol traffic, or packets between the
wireless routers 30. The wireline virtual tunnel 70 may be set up
and maintained by one or more wireline-specific control channels
74. The control channels 74 include signaling channel 74a and
routing message channel 74b. The wireless virtual tunnel 72
transports wireless protocol traffic, or packets between the
wireless routers 30. The wireless virtual tunnel 72 may be set up
and maintained by one or more wireless-specific control channels
76. As described in more detail below, the control channels 76 may
include a signaling channel 76a used by a signaling protocol 78 and
a routing message channel 76b used by a radio routing protocol
79.
[0060] In one embodiment, the wireline protocol traffic comprises
IP packets and the wireless protocol traffic comprises radio
frames. As described in more detail below, the wireline virtual
tunnel 70 is used by the wireless routers 30 for call set up,
resource reservation, air bandwidth allocation and routing of calls
in the wireless network 10. The wireless virtual tunnel 72 is used
for soft handoff and mobility management of calls within the
wireless network 10. The virtual paths 70 and 72 may be set up on a
per neighbor, per call or other suitable basis. In addition,
multiple virtual paths 70 and/or 72 may be provided for each
neighbor and/or call.
[0061] In a particular embodiment, the virtual paths 70 and 72 are
each a multi-protocol label switch (MPLS) path. The MPLS paths
provide high speed multicasting and rerouting of traffic for soft
handoff operations. In the MPLS embodiment, IP packets and radio
frames are routed based on MPLS labels added by the wireless
routers 30. The wireline MPLS paths 70 may be provisioned and
controlled based on resource reservation protocol (RSVP), label
distribution protocol (LDP), open shortest path first (OSPF),
routing information protocol (RIP), and border gateway protocol
(BGP) channels 74.
[0062] The wireless MPLS path 72 may be provisioned and controlled
using extended RSVP, OSPF, RIP, and/or BGP channels 76. In this
embodiment, the signaling protocol 78 is used by the wireless
routers 30 to set up and tear down paths and to perform resource
reservation, resource updates, path routing, and soft handoffs. The
signaling protocol may be an extension of existing RSVP/LDP
protocols, use a specialized circuit, or be established using
transport control protocol (TCP) or signal as the transport
protocol.
[0063] The radio routing protocol 79 is used by the wireless
routers 30 to communicate routing messages over the routing message
channel 76b. In particular, the wireless router 30 makes forwarding
decisions using the radio routing protocol 79 as well as the
destination IP address, MPLS labels and call ID based on an IP
forwarding table, IP to MPLS path forwarding table, MPLS incoming
path to outgoing forwarding table, call ID to LSP ID, a bit map of
active LSPs to a given sector for a given call ID, and list of
router IDs for a given path. Each outgoing decision has primary and
secondary paths. If the primary path fails, the secondary path is
used for the outgoing traffic. The radio routing protocol 79 is
also used to load and maintain the forwarding table within each
wireless router 30, maintain an overall consistent view of the
topology of the network, and the reachability within the network.
In addition, the radio routing protocol 79 responds to dynamic
changes in the network's topology or reachability state and selects
optimal paths based on a consistent interpretation of a per-hop
cost or other metric.
[0064] To support services for the wireless traffic, the wireless
routers may access traffic and control interfaces 80. The traffic
and control interfaces 80 may include a media gateway controller
82, wireless application protocol (WAP) server 84, policy
management server 85, call agent controller 86, mobile manager 88,
and AAA server 89. The wireless routers 30 may communicate with the
traffic and control interfaces 80 through media gateway control
protocol (MGCP), common open policy service (COPS) and other
suitable protocols.
[0065] FIGS. 4A-C illustrate protocol stacks for the mobile devices
44, wireless-specific routers 30, and wireline-specific routers 20
in accordance with one embodiment of the present invention. In this
embodiment, the protocol stacks are transparent to the upper layer
protocols. It will be understood that other suitable types of
protocols may be used for or in connection with the
wireless-specific routers 30.
[0066] FIG. 4A illustrates a protocol stack for a wireless router
30 including an integrated base station. In this embodiment, the
wireless router 30 includes a protocol stack 90 including wireless
QoS/call processing layer 91, MPLS layer 92, link access control
(LAC) layer 93, media access control (MAC) layer 94, wireless MPLS
(WMPLS) layer 95, physical layer 96, radio frame layer 97, WMPLS
layer 98, physical layer 99, and RF layer 100. Packets, which may
be any suitable datagram, from the core IP network are received by
the physical layer 96 and processed by the MPLS layer 92 and air
QoS/call processing layer 91. Packets communicated between the
wireless routers 30 are processed through the air QoS/call
processing layer 91, LAC layer 93, MAC layer 94, WMPLS layer 95 and
physical layer 96 on the transmit side and by the physical layer
99, WMPLS layer 98 and radio frame layer 97 on the receive side.
Transmissions from the wireless router 30 to a mobile device 44 are
transmitted through the radio frame layer 97 and RF layer 100.
[0067] FIG. 4B illustrates a protocol stack 101 for a wireless
router 30 with a remote base station. The protocol stack 101
includes a wireless QoS/call processing layer 102, MPLS layer 103,
physical layer 104, LAC layer 105, MAC layer 106, WMPLS layer 107,
radio frame layer 108, WMPLS layer 109, physical layer 110, and
physical layer 111 at the wireless router 30. At the base station,
the protocol stack 101 includes physical layer 112, radio frame
layer 113, and RF layer 114. Packets are received by the wireless
router 30 from the core IP network and communicated between the
wireless routers 30 as previously described in connection with
protocol stack 90. Communication from the wireless router 30 to the
remote base station are processed by the radio frame layer 108 and
the physical (T1) layer 111. At the base station, packets from the
wireless router 30 are received by the physical (T1) layer 112 and
processed by the radio frame layer 113. Radio frames are
transmitted from the base station though the RF layer 114.
[0068] FIG. 4C illustrates discrete protocol stacks for different
types of traffic transmission within the network. In particular,
protocol stack 115 is used for core IP communications in which
packets are processed by physical layer 115a, MPLS layer 115b, and
air QoS layer 115c. Protocol stack 116 is used in the wireless
router 30 for user traffic. In this embodiment, user traffic is
processed by physical layer 116a, WMPLS layer 116b, link layer 116c
and air QoS layer 116d. Protocol stack 117 is used in the wireless
router 30 for signal traffic. In this embodiment, signal traffic is
processed by physical layer 117a, WMPLS layer 117b, link layer
117c, and call processing layer 117d. Protocol stack 118 is used
for inter wireless router 30 communications in which radio frames
are processed by physical layer 118a, WMPLS layer 118b and radio
frame layer 118c. Protocol stack 119 is used in a base station to
communicate with the mobile device 44. The mobile device 44 is
communicated with through RF physical layer 119a and radio frame
layer 119b.
[0069] FIGS. 5A-B illustrate packets for transmission in the MPLS
paths 70 and 72 between routers 20 and/or 30 in accordance with one
embodiment of the present invention. In particular, FIG. 5A
illustrates a wireline protocol packet 120 for transmission in the
wireline MPLS path 70. FIG. 5B illustrates a wireless protocol
packet 122 for transmission in the wireless MPLS path 72.
[0070] Referring to FIG. 5A, the wireline protocol packet 120
includes an IP packet 124 and an MPLS label 126. The IP packet 124
includes an IP header 128 and data payload 130. The MPLS label 126
provides routing information for the IP packet 124 between the
wireline and/or wireless routers 20 and 30. A series of MPLS labels
126 may be appended to the IP packet 124 to identify additional
processing information for the IP packet 124. In this way, traffic
is efficiently routed between the wireless routers 30 and
distributively processed by the wireless routers 30.
[0071] Referring to FIG. 5B, the wireless protocol packet 122
includes a radio frame 132 and an MPLS label 134. The radio frame
132 includes a radio frame header 136 and a data payload 138. The
radio frame 132 is used to communicate over the RF layer with the
mobile devices 44. A MPLS label 134 provides routing information
for the radio frame 132 between the wireless routers 30. As
described in more detail below, radio frames 132 for a call are
routed between an active set of wireless routers 30 for soft
handoff and mobility management of the call. Additional MPLS labels
may be attached to the radio frame 132 to identify additional
routing and/or traffic management processing for the frame 132.
[0072] A synchronization bias field 140 may be provided in the
wireless protocol packet 122 to allow synchronization of different
instances of a same radio frame 132. In particular, as described in
more detail below, multi-cast traffic may include a synchronization
bias to ensure that all traffic is transmitted to the mobile device
44 simultaneously. Alternatively, traffic could be multi-cast at
different times to account for different delays in the MPLS paths
72. Further still, traffic could be received and synchronized at
the mobile device 44. For ingress traffic from mobile device 44,
the instances may be synchronized based on a sequence count in
place of the synchronization bias. Thus, the synchronization bias
may be omitted where other information is provided for
synchronization.
[0073] FIG. 6 illustrates details of the wireless router 30 in
accordance with one embodiment of the present invention. In this
embodiment, the wireless router 30 is implemented in a card-shelf
configuration with its functionality distributed between discrete
cards. The cards are connected by a mesh network, one or more
buses, a backplane, or other suitable communication channel.
Similarly, within each card, components are connected by a mesh
network, one or more buses, a backplane, or other suitable
communication channel.
[0074] Referring to FIG. 6, the wireless router 30 includes a
plurality of wireless peripherals 150, a plurality of network
peripherals 152, and a traffic controller 154. The wireless
peripherals 150 and the network peripherals 152 each may include an
interface and a network information base for processing and
handling traffic received from the wireless and wireline portions
of the network, respectively. The interfaces may be technology
dependent or independent. In the later case, the interfaces may
combine traffic from different technologies into a datagram and/or
may convert between technologies.
[0075] The wireless peripherals 150 may comprise a plurality of
cards to handle disparate access technologies. For example, the
wireless router 30 may have separate interfaces for GSM, CDMA 2000,
WCDMA, and IS-95. Similarly, the network peripherals 152 may
include disparate types of cards for connections to disparate
wireline formats. Thus, each wireless router 30 may support a
plurality of wireless and wireline technologies. The wireless
peripherals 150 may be directly connected to a radio front end
which may be internal or external to the wireless router 30. In
operation, the wireless and network peripherals 150 and 152
categorize and label packets for routing and grouping by traffic
controller 154.
[0076] The traffic controller 154 and peripherals 152 and 150 may
each be implemented in hardware, software stored in a
computer-readable medium, and/or a combination of hardware and
software. The hardware may comprise a field programmable gate array
(FPGA) programmed to perform the functionality of cards, an
application specific integrated circuit (ASIC) designed to perform
the functionality of the cards and/or a general purpose processor
program by software instructions to perform the functionality of
the cards.
[0077] In one embodiment, the traffic controller 154 includes a QoS
engine 160, selection and distribution unit 162, central processing
unit (CPU) 164, timing unit 166, power and interference manager
168, packet classification module 170, IP security module 172,
radio resource module 174, call processor 176, and communication
module 178. The QoS engine 160 manages transmission resources
within the wireless router 30. The QoS engine 160 may include a
dynamic flow manager, a performance monitor, a dynamic bandwidth
estimator and a multiple dimension resource queuing system for
processing and handling traffic. Further information regarding the
network information base, the dynamic flow manager, the performance
monitor, the dynamic bandwidth estimator, and the multiple
dimension resource queuing system is described in co-owned U.S.
Patent Applications entitled "Method and System for Queuing Traffic
in a Wireless Communications Network" and "Method and System for
Managing Transmission Resources in a Wireless Communications
Network," previously incorporated by reference.
[0078] The timing unit 166 provides synchronization for elements
within the wireless router 30. The CPU 164 processes software to
perform the functionality of the SDU 162. The power and
interference manager 168 manages transmission power of the wireless
router 30 to control interference between the wireless router 30
and adjacent or co-channel neighbors.
[0079] The SDU 162 includes a virtual path generator 180, a
selector 182 a distributor 184, a segmentation and reassembly (SAR)
unit 186 and traffic processing tables 190. The virtual path
generator 180 configures MPLS and/or other suitable types of
virtual paths using forwarding tables, trigger rules based on
current conditions and other suitable criteria. As previously
described, the MPLS paths allow for wireline and wireless specific
traffic to be communicated between the routers 20 and/or 30.
[0080] The selector 182 and distributor 184 are used in connection
with soft handoff call processing. In particular, the selector 182
selects one of a plurality of instances of ingress traffic from a
mobile device 44 for forwarding to a destination device. The
selector 182 synchronizes the instances as necessary and selects an
instance of the packet based on pattern matching on a
frame-by-frame basis, quality selection using error-correction bits
or other suitable criteria. Synchronization may be based on frame
sequence numbers (FSN) in the packets which include time stamps. In
one embodiment, a first arriving instance of a packet meeting
specified parameters is selected.
[0081] The distributor 184 multicasts egress traffic received for
transmission to the mobile device 44. Traffic is multicast to an
active set of wireless routers 30 for simultaneous transmission to
the mobile device. In this way, the mobile device 44 may
communicate with a plurality of wireless routers 30 to ensure its
call is not dropped at the cell boundaries or otherwise.
[0082] The SAR unit 186 segments IP packets received from the
wireless network into radio frames for transmission to the mobile
devices 44 and/or to secondary wireless routers 30 for transmission
to the mobile devices 44. The SAR unit 186 reassembles radio frames
received from the mobile devices 44 into IP packets for
transmission within the core IP network.
[0083] The traffic processing tables 190 include routing tables and
forwarding tables for processing traffic. Based on the routing
tables and the forwarding tables, the traffic controller 154 adds
MPLS labels to IP packets and to radio frames for routing in the
network 10. As described in more detail below, the traffic
processing tables 190 also include a list of all active calls for
the wireless router 30 and a bandwidth allocation table.
[0084] The packet classification module 170 classifies packets
based on label and/or header information for processing within the
traffic controller 154. The IP security module 172 does IPSec
protocol or other security protocol. The radio resource module 174
does radio resource management. The call processor 176 sets up
calls in the traffic controller 154 and includes the radio routing
protocol 79. The communication module 178 allows the traffic
controller 154 to communicate with gateways, services, policy
managers, IP routers, base stations, call agents and other suitable
remote nodes and resources.
[0085] During operation, when a call arrives, a list of wireless
routers 30 are identified from the active list. The radio routing
protocol 79 considers the metric for each given LSP between two
wireless routers and identifies a list of router IDs and LSPs for a
given tail-end router ID, where the head-end is the point at which
traffic is transmitted in the LSP and the tail-end is the point at
which traffic is received from the LSP. Correspondingly, the bit
map of the call ID and the next hop LSP is updated. Path, burst,
and bandwidth allocations are negotiated and set up during the set
up of the LSPs. Next, the LSPs are set up as per the active list
given by the mobile device and routing protocol 79. The primary is
selected and a multicasting path is enabled as well as incoming
paths for the selection are enabled. Due to mobility, wireless
routers 30 are added and deleted from the active list. Thus, the
radio routing protocol 79 is consulted for new LSPs as well as for
deletions. After obtaining new LSPs from the radio routing protocol
79, the LSPs are set up after negotiation.
[0086] After call set up, traffic is routed by the radio routing
protocol 79 as previously described. In one embodiment, two
anchoring points are provided for traffic distribution. The first
anchoring point is located at the interface between the core IP
network and the air router, or gateway network. This anchoring
point is fixed in the wireline and need not move to other gateways
as the mobile device 44 moves. For mobile devices that travel long
distances, the first anchoring point may be moved by identifying a
new anchoring point, configuring the new anchoring point for the
call, and informing the ends of the call or session of the new
anchor point.
[0087] In operation, after receiving the traffic from the core IP
network, the edge gateway forwards traffic through the
pre-established or dynamic MPLS path to the current primary node in
the active list. The current primary node in the active list is the
second anchoring point. The primary node is responsible for
distribution of the traffic to all secondary nodes in the active
list. Distribution of the traffic is accomplished using MPLS
multicast. Initially, the multicast path is set up between current
primary and other nodes in the active list during the call
establishment phase.
[0088] As the mobile device moves from the primary node, power
levels at the primary unit will degrade. If the power falls below a
certain drop threshold, the primary wireless router may determine a
next primary router using the control message from the mobile unit.
The control message includes the power level associated with the
new primary. In particular, the radio routing protocol 79
determines if the primary anchoring point needs to be changed which
depends on the radius of coverage and the metrics of the LSPs from
the new primary to members in the active list.
[0089] For micro mobility, the existing primary router signals the
new primary router indicating the handover of the primeship as well
as the list of active wireless routers. After receiving the control
message, the new primary router which is receiving the strongest
signals confirms that it is ready to take over control of traffic
distribution. It establishes the multicast MPLS paths for the
secondary routers in the active list. This may be accomplished
using another control message back to the current primary node
indicating that the new node is ready to host the multicast.
[0090] FIG. 7 illustrates details of the QoS engine 160 of the
wireless router 30 in accordance with one embodiment of the present
invention. In this embodiment, IP packets for flows transmitted
through the wireless routers 30 are buffered in the queuing system
30 for traffic shaping and conditioning. Wireless specific radio
frames in the MPLS paths are not queued to maintain synchrony of
the frames.
[0091] Referring to FIG. 7, traffic from a wireline router 20 is
received at the QoS engine 160 and flow-specific traffic
conditioning 200 applied by metering, policing, shaping and marking
the traffic. Location-specific rate control and TCP flow control
202 are then applied to the traffic. Location-specific traffic
conditioning 204 is next applied, followed by sector specific
traffic conditioning and power/interface management 206. The
conditioned traffic is then passed to the SAR unit 186 for
segmentation into the radio frames and transmission to the mobile
devices 44.
[0092] For traffic received from the mobile devices 44, the SAR
unit 186 reassembles the radio frames into an IP packet.
Flow-specific traffic conditioning 210 is applied to the IP packet
by metering, policing, shaping, and marking the packet.
Location-specific rate control and TCP flow control 212 is next
applied to the packet. Next, location-specific traffic conditioning
214 is applied to the packet. The conditioned packet is then
transmitted over the wireline network.
[0093] FIG. 8 illustrates details of the traffic processing tables
190 in accordance with one embodiment of the present invention. In
this embodiment, the traffic processing tables 190 include routing
tables 250, forwarding tables 252, active mobile list 254 and
bandwidth availability table 256. Routing tables 250 include a RIP
table 260, OSPF table 262, BGP table 264 radio discovery protocol
(RDP) table 266 and radio routing protocol (RRP) table 268. The RDP
table 266 is described in detail in co-owned U.S. Patent
Application entitled "Method and System for Configuring Wireless
Routers and Networks," previously incorporated by reference. The
RRP table 268 is configured from the RDP table 266 and includes
dynamic routing information for the network. In particular, the RRP
table 268 maintains a list of routers for each path of an active
call. The routing tables 250 are used to construct the forwarding
tables 252.
[0094] The forwarding tables 252 include an IP forwarding table
270, MPLS tunnel table 272, outgoing LSP table 274 and incoming LSP
table 276. The IP forwarding table 270 represents the IP topology
for the network 10 and is further described below in connection
with FIG. 9. The MPLS tunnel table 272 represents the RF topology
for the network 10 and is further described below in connection
with FIG. 10. The outgoing LSP table 274 identifies multi-cast LSPs
for soft handoff call processing and is further described below in
connection with FIG. 11. The incoming LSP table 276 identifies the
LSPs used in connection with selection operations for soft handoff
call processing and is further described below in connection below
with FIG. 12. The LSPs are maintained on a per call basis for
active calls. The bandwidth availability table 256 provides
reserved bandwidth for soft handoff call processing and is further
described below in connection with FIG. 13.
[0095] The active mobile list 254 is maintained on a per call
basis. For each call, the active mobile list 254 stores a call
identifier 280, active neighbors 282, candidate neighbors 284, and
all neighbors 286. The active neighbors 282 are neighbors of the
wireless router 30 that are actively processing the call along with
the wireless router 30. The candidate neighbors 284 are neighbors
of the wireless router 30 that are situated to process the call but
are not actually engaged in call processing. All neighbors 286
include all potential neighbors for the wireless router 30.
[0096] FIG. 9 illustrates details of the IP forwarding table 270 in
accordance with one embodiment of the present invention. In this
embodiment, the IP forwarding table 270 includes a destination IP
address, outgoing interface ID for primary and secondary routers,
outgoing port ID for primary and secondary routers, data link
address (logical circuit) for primary and secondary routers, hop
count associated with destination for primary and secondary routers
and multicast indicator. The secondary routers are used in response
to failure of the primary router. It will be understood that the IP
forwarding table 270 may be otherwise implemented in connection
with the present invention.
[0097] FIG. 10 illustrates details of the MPLS tunnel table 272 in
accordance with one embodiment of the present invention. In this
embodiment, the MPLS tunnel table 272 includes a head end router
ID, tail end router ID, next hop router ID, label, tunnel ID, next
hop router ID, type of service (TOS), outgoing interface ID, delay
metric, throughput metric, level three ID used by the tunnel, local
rerouting for protection, set up priority, holding priority, number
of hops, and delay constraint. It will be understood that the MPLS
tunnel table 272 may be otherwise implemented in connection with
the present invention.
[0098] FIG. 11 illustrates details of the outgoing LSP table 274 in
accordance with one embodiment of the present invention. The LSPs
are predefined based on the RF network topology and can be readily
activated by the wireless router 30 for soft handoff call
processing. In this embodiment, the outgoing LSP table 274
maintains a list of all potential LSPs for each active call on a
sector by sector basis. Each LSP is associated with another
wireless router 30. Each LSP to a router 30 is activated for a call
by writing a "1" into the LSP for the router 30 and the call.
Similarly, a LSP is deactivated by writing a "0" in the LSP.
[0099] FIG. 12 illustrates details of the incoming LSP table 276 in
accordance with one embodiment of the present invention. In this
embodiment, the incoming LSP table 276 maintains a list of all
potential LSPs for each active call on a per sector basis. Each LSP
is associated with another wireless router 30. Each LSP to a router
30 is established by writing a "1" into the LSP for the wireless 30
in the call. Similarly, a LSP is deactivated by writing a "0" in
the LSP. In this way, as described in connection with the outgoing
LSP table 274, the LSPs are predefined based on the network RF
topology and can be readily activated by the wireless router 30 for
soft handoff call processing. The sectors are one or more wireless
routers.
[0100] FIG. 13 illustrates details of the soft handoff bandwidth
availability table 256 in accordance with one embodiment of the
present invention. In this embodiment, reserved and available
bandwidth for soft handoffs for each neighboring router are stored
for outgoing and incoming LSPs. The neighbors may be adjacent or
co-channel neighbors. Label ranges for the soft handoff are also
stored for each neighboring router. It will be understood that
additional or other information may be stored and that available
bandwidth may be otherwise determined in connection with the
present invention.
[0101] FIG. 14 is a flow diagram illustrating a method for
configuring the wireless routers for call processing in accordance
with one embodiment of the present invention. The method begins at
step 350 in which a mobile device 44 is activated. Next, at step
352, the mobile device 44 identifies an active set of wireless
routers 30 for the call. The active set may be identified based on
responses received from base stations/wireless routers 30 in the
area of the mobile device 44.
[0102] Proceeding to step 354, the mobile device 44 selects a
primary wireless router 30 for the active set. The primary wireless
router 30 may be the wireless router closest to the mobile device
44 returning the strongest signal. At step 356, the mobile device
44 communicates the active set and the status as primary to the
primary wireless router 30. At step 358, the primary wireless
router 30 allocates resources for the call.
[0103] Next, at step 360, the primary wireless router 30 informs
the secondary wireless routers 30 in the active set of their status
as secondary wireless routers 30. At step 362, the secondary
wireless routers 30 allocate resources for the call. Next, at step
364, MPLS paths are configured between the primary and secondary
routers 30 for processing of the call. Step 364 leads to the end of
the process by which call-setup is performed by wireless routers 30
in a distributed system architecture.
[0104] FIG. 15 illustrates soft handoff of a call in an exemplary
wireless communications network 370. Referring to FIG. 15, the
exemplary network 370 includes core IP network 372 coupled to a
wireless router network 374 through an edge wireless router 376.
The wireless router network 374 includes a primary wireless router
378 for a call of a mobile device 380 and secondary wireless
routers 382. Wireless router 384 is currently inactive for the
call.
[0105] LSPs 386 are configured between the primary and wireless
routers 378 and 382 and between the primary and edge wireless
routers 378 and 376. The primary and edge wireless routers 378 and
376 form anchoring points for call processing at the edge of the
core IP network and at the primary wireless router 378. The LSPs
386 provide synchronized framing for distribution and selection
between neighbors of wireless traffic and fast rerouting for soft
handoff using RSVP.
[0106] In response to the wireless unit 380 transitioning location
and identifying a new active set including wireless router 384 as
the new primary wireless router, the LSPs 386 are terminated and
LSPs 390 established for soft handoff operations. It will be
understood that the new primary wireless router may be a previous
secondary wireless routers in an active set for the call. Further
information regarding soft handoff and mobility management are
described in more detail below in connection with FIGS. 16-20.
[0107] FIG. 16 is a flow diagram illustrating a method selecting
ingress wireless traffic from an active set of wireless routers for
soft handoff in accordance with one embodiment of the present
invention. The method begins at step 400 in which an instance of a
radio frame is received at a plurality of wireless routers 378 and
382 in an active set of wireless routers for a call. Next, at step
402, instances from the secondary wireless routers 382 are routed
to the primary wireless router 378.
[0108] Proceeding to step 404, the primary wireless router 378
selects one of the radio frame instances for transmission to the
destination device for the call. As previously discussed, an
instance radio frame may be selected based on frame quality. Thus,
the highest quality instance of the radio frame is chosen for
transmission to the destination device. At step 406, the selected
instance of the radio frame is inserted into an IP packet for
transmission over the core IP network.
[0109] Next, at decisional step 408, if the IP packet is
incomplete, the No branch returns to step 400 in which instances of
a next radio frame of the call are received and one of the
instances selected for insertion into the IP packet. After the IP
packet is complete, the Yes branch of decisional step 408 leads to
step 410. At step 410, the IP packet is transmitted over the core
IP network 372 to the destination device.
[0110] Next, at decisional step 412, if the call is not completed,
the No branch returns to step 400 in which instances of a next
radio frame continue to be received, processed, and packetized for
transmission to the destination device. Upon completion of a call,
the Yes branch of decisional step 412 leads to the end of the
process by which soft handoff is performed by the distributed
wireless routers.
[0111] FIG. 17 is a flow diagram illustrating a method for
distributing egress wireless traffic between an active set of
wireless routers for soft handoff in accordance with one embodiment
of the present invention. The method begins at step 450 in which an
IP packet is received from the core IP network 372 and forwarded to
the primary wireless router 378. At step 452, the IP packet is
segmented into radio frames for transmission to the mobile device
380.
[0112] Proceeding to step 454, instances of the next radio frame in
the IP packet are multicast to the secondary wireless routers 382
in the active set of routers based on the MPLS multicast table 274.
At step 456, instances of the radio frame are transmitted from each
of the active routers 378 and 382 to the mobile device 380 for
maximum signal reception. The signals are transmitted synchronously
to the mobile device 380 by bypassing queuing for the multicast
radio frames. In one embodiment, one or more of the primary and/or
secondary wireless routers may drop the packets due to weak radio
links, suitable number of other links, or other suitable
operational reasons.
[0113] Next, at decisional step 458, if radio frames in the IP
packet have not been completely processed, the No branch returns to
step 454 in which the next radio frame is multicast for
transmission to the mobile device 380. Upon completion of
processing the radio frames in the IP packet, the Yes branch of
decisional step 458 leads to decisional step 460.
[0114] At decisional step 460, if the call is not complete, the No
branch returns to step 450 in which the next IP packet for the call
is received and processed as previously described. Upon call
completion, the Yes branch of decisional step 460 leads to the end
of the process by which soft handoff is provided for egress
traffic.
[0115] FIG. 18 illustrates a method for synchronizing multicast
egress traffic in accordance with one embodiment of the present
invention. In this embodiment, traffic for a mobile device 480 is
received from the core IP network at a primary router 482. The
primary router 482 multicast the signal to secondary router 484
over LSP1 and to secondary router 486 over LSP2. LSP1 has a line
delay of 0.5 milliseconds while LSP2 has a line delay of 1.0
millisecond. The primary router directly transmits a signal to the
mobile device 480 and thus has no line delay.
[0116] To account for the differing line delays in the LSPs, each
SDU 490 includes a delay bias 492. The SDU 490 for the primary
router adds a synchronization bias of 0 milliseconds to traffic
transmitted through to LSP2, of 0.5 milliseconds of traffic
transmitted through LSP1, and of 1 millisecond for traffic directly
transmitted from the primary router 482. The synchronization bias
is included within the wireless protocol packet 122 as previously
described in connection with FIG. 5B.
[0117] In each router 482, 484, and 486, the delay bias 492 applies
the synchronization bias 140 to delay packet transmission to the
mobile device 480. Thus, the primary router 482 will transmit the
packet 1.0 milliseconds after receipt due to delay biasing, while
the secondary router 484 will transmit the packet 0.5 milliseconds
after transmission from the primary router 482 due to line delay
plus 0.5 milliseconds after receipt due to delay biasing for a
total of a 1.0 millisecond delay and the secondary router 486 will
transmit the packet 1.0 millisecond after transmission from the
primary router 482 due to line delay and 0 milliseconds after
receipt due to delay biasing for a total of a 1.0 millisecond
delay. Accordingly, the packets will be simultaneously transmitted
for receipt and processing by the mobile device 480. It will be
understood that the packets may be otherwise synchronized without
departing from the scope of the present invention.
[0118] In the illustrated embodiment, the synchronization bias is
equal to the maximum delay of an LSP for the active set. The
synchronization bias is adjusted each time the active set of
wireless routers 30 changes to be the maximum delay of the LSPs for
the current active set. Thus, the synchronization bias is
dynamically adjusted based on the active set of wireless routers 30
for a call.
[0119] FIG. 19 illustrates soft handoff functionality of the
wireless router 378 and 382 in accordance with one embodiment of
the present invention. In this embodiment, the radio frames are
IS-95 frames used in connection with CDMA cellular technology. It
will be understood that the methodology may be used in connection
with any other suitable types of radio frames.
[0120] Referring to FIG. 19, mobile traffic is received as IS-95
frames from the mobile device 380. The radio frames are passed to
bridge 502 which transmits the frames to the primary wireless
router 378 through the LSPs 386. For the primary wireless router
378, selector 504 receives radio frames from the local RF element
500 and from the secondary wireless routers 382. The selector
selects a highest quality IS-95 frame and passes it to the
demultiplexer 506. The demultiplexer demultiplexes user data and
signals. The multiplex traffic is passed to traffic control 508 or
SAR unit 510.
[0121] Traffic control 508 performs call processing, access
messaging, paging messaging, handoff messaging, signal messaging
and other control of flows in the wireless router. Control traffic
from traffic control 508 and user traffic from the demultiplexer
506 are passed to the SAR unit 510 for reassembly into IP packets.
The IP packets afforded to the QoS engine 512 for flow conditioning
including TCP rate control, geo-specific conditioning, power and
interface management. From the QoS engine 512, packets are embedded
in the SONET protocol and transmitted over the core IP network
372.
[0122] IP packets from a wireline router in the core IP network 372
are received at the wireless router 378 or 382 at the QoS engine
520. From the QoS engine, traffic may be passed to the traffic
control 508 for processing, passed to SAR unit 522 for
segmentation, or routed to another wireless router in the POS
format. At packet segmentation 522, IP packets are segmented into
IS-95 frames which are synchronized by multiplexer 524. The IS-95
frames are multicast at distributor 526 from the primary wireless
router 378 to the secondary wireless routers 382. For the primary
wireless router 378, the IS-95 frame is passed from the distributor
526 to the RF channel element 528 for forwarding to the antenna for
transmission to the wireless device 380. For secondary wireless
routers 382, the IS-95 frame is received from the primary wireless
router 378 and synchronized 530 prior to being passed to the RF
channel element 528.
[0123] FIG. 20 illustrates a method for mobility management in
accordance with one embodiment of the present invention. In this
embodiment, the wireless routers 378, 382, and 384 intercommunicate
with one another and the mobile device 380 to provide mobility
management within the network 370.
[0124] Referring to FIG. 20, the method begins at step 550 in which
an active set of wireless routers are provided for a call. The
active set includes an existing primary wireless router 378 and
existing secondary wireless routers 382. At step 552, a new active
set of wireless routers is received from the mobile device 380. The
new active set of wireless routers identifies a new primary
wireless router 384 and new secondary wireless routers 382. The new
secondary wireless routers 382 may include some or all of the
previous secondary wireless routers.
[0125] Proceeding to step 554, LSPs between the existing primary
wireless router 378 and secondary wireless routers 382 are
terminated. At step 556, LSPs 390 between the new primary wireless
router 384 and new secondary wireless routers 382 are established.
Thus, all further selection and distribution of traffic will be
performed through the new primary wireless router 384.
[0126] At step 558, the existing primary wireless router 378
informs the destination device for the call of the new primary
router 384. The destination device may be an edge router or the
other end of a call or session. Thus, the destination device will
address further traffic to the mobile device 380 to the new
wireless router 384. At step 560, traffic is queued at the new
primary wireless router 384 while the existing primary wireless
router 378 processes existing traffic. Thus, the traffic will be
delivered in the order in which it is received.
[0127] At step 562, the existing primary wireless router 378
finishes processing traffic for the call. At step 564, the new
primary wireless router 384 is activated and begins to process and
transmit queued traffic. In this way, mobility management is
provided in a distributed architecture. Hard handoffs without
packet and without misordering may also be provided in this way
using only primary nodes.
[0128] Although the present invention has been described with
several embodiments, various changes and modifications may be
suggested to one skilled in the art. It is intended that the
present invention encompass such changes and modifications as fall
within the scope of the appended claims.
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