KWAK YONG WON (KR)
LEE JIN (KR)
KIM YONG HO (KR)
KWAK YONG WON (KR)
LEE JIN (KR)
WO2004021620A2 | 2004-03-11 | |||
WO2001031963A1 | 2001-05-03 |
GUPTA V. ET AL.: "Media Independent Handover", IEEE 802.21 WORKING GROUP, 14 January 2005 (2005-01-14), XP008136399
GUPTA V. ET AL.: "A Generalized Model for Link Layer Triggers", IEEE 802.21 WORKING GROUP, 1 March 2004 (2004-03-01), XP002344485
See also references of EP 1856940A4
1. | A method for providing mobility management protocol information to a mobile terminal, the method comprising: establishing a unified interface to an upper layer of the mobile terminal for managing messages to and from at least one of a homogeneous network and a heterogeneous network; discovering an accessible link of the at least one of a homogeneous network and a heterogeneous network for performing handover; and informing the upper layer of the accessible link via the unified interface, wherein the step of informing the upper layer comprises providing the upper layer with mobility management protocol information of the at least one of a homogeneous network and a heterogeneous network prior to establishing a connection with the accessible link. |
2. | The method of claim 1, further comprising requesting a scan of the at least one of a homogeneous network and a heterogeneous network via the unified interface to determine the presence of the accessible link of the at least one of a homogeneous network and a heterogeneous network for performing the handover. |
3. | The method of claim 1, further comprising requesting information related to the accessible link of the at least one of a homogeneous network and a heterogeneous network from an information server operationally connected to the at least one of a homogeneous network and a heterogeneous network. |
4. | The method of claim 3, wherein the step of requesting information comprises requesting mobility management protocol information of the at least one of a homogeneous network and a heterogeneous network. |
5. | The method of claim 1, wherein the unified interface is a media independent handover function (MIHF) entity. |
6. | The method of claim 1, wherein the upper layer comprises an upper management entity for managing homogeneous and heterogeneous network links associated with the mobile terminal. |
7. | The method of claim 1, wherein the upper layer comprises at least one mobility management protocol for managing a respective mobile terminal mobility method. |
8. | A method for providing mobility management protocol information to a mobile terminal, the method comprising: establishing a unified interface to an upper layer of the mobile terminal for managing messages to and from at least one of a homogeneous network and a heterogeneous network; establishing a connection with an accessible link of the at least one of a homogeneous network and a heterogeneous network for performing handover; and receiving in the upper layer information from the unified interface related to the established connection, wherein the step of receiving the information comprises receiving mobility management protocol information of the at least one of a homogeneous network and a heterogeneous network. |
9. | The method of claim 8, wherein the step of receiving the information comprises receiving in the upper layer a request from the unified interface for establishing a network address for the at least one of a homogeneous network and a heterogeneous network. |
10. | The method of claim 9, wherein the network address is an Internet protocol (IP) address. |
11. | The method of claim 8, wherein the unified interface is a media independent handover function (MIHF) entity. |
12. | The method of claim 8, wherein the upper layer comprises an upper management entity for managing homogeneous and heterogeneous network links associated with the mobile terminal. |
13. | The method of claim 8, wherein the upper layer comprises at least one mobility management protocol for managing a respective mobile terminal mobility method. |
14. | The method of claim 8, wherein the step of receiving the information comprises providing the upper layer with mobility management protocol information to a specific mobility management protocol related to the information. |
15. | The method of claim 9, further comprising: providing the upper layer with mobility management protocol information by providing the information to a specific mobility management protocol related to the information; and establishing the network address for the at least one of a homogeneous network and a heterogeneous network when the mobility management protocol information is provided to the specific mobility management protocol. |
16. | The method of claim 9, further comprising establishing the network address for the at least one of a homogeneous network and a heterogeneous network. |
17. | A method for providing mobility management protocol information to a mobile terminal, the method comprising: establishing a unified interface to an upper layer of the mobile terminal for managing messages to and from at least one of a homogeneous network and a heterogeneous network; establishing a connection with an accessible link of the at least one of a homogeneous network and a heterogeneous network for performing handover; and informing the upper layer of the established connection with the accessible link via the unified interface, wherein the step of informing the upper layer comprises providing the upper layer with mobility management protocol information of the at least one of a homogeneous network and a heterogeneous network. |
18. | The method of claim 17, wherein the unified interface is a media independent handover function (MIHF) entity. |
19. | The method of claim 17, wherein the upper layer comprises an upper management entity for managing homogeneous and heterogeneous network links associated with the mobile terminal . |
20. | The method of claim 17, wherein the upper layer comprises at least one mobility management protocol for managing a respective mobile terminal mobility method. |
21. | The method of claim 17, wherein the step of providing the upper layer with mobility management protocol information comprises providing the information to a specific mobility management protocol related to the information. |
22. | A method for providing mobility management protocol information to a mobile terminal, the method comprising: establishing a unified interface to an upper layer of the mobile terminal for managing messages to and from at least one of a homogeneous network and a heterogeneous network; establishing a connection with an accessible link of the at least one of a homogeneous network and a heterogeneous network for performing handover; and receiving in the upper layer a request from the unified interface for establishing a network address for the at least one of a homogeneous network and a heterogeneous network, wherein the step of receiving a request for establishing a network address comprises providing the upper layer with mobility management protocol information of the at least one of a homogeneous network and a heterogeneous network. |
23. | The method of claim 22, wherein the network address is an Internet protocol (IP) address. |
24. | The method of claim 22, wherein the unified interface is a media independent handover function (MIHF) entity. |
25. | The method of claim 22, wherein the upper layer comprises an upper management entity for managing homogeneous and heterogeneous network links associated with the mobile terminal. |
26. | The method of claim 22, wherein the upper layer comprises at least one mobility management protocol for managing a respective mobile terminal mobility method. |
27. | The method of claim 22, wherein the step of providing the upper layer with mobility management protocol information comprises providing the information to a specific mobility management protocol related to the information. |
28. | The method of claim 27, further comprising establishing the network address for the at least one of a homogeneous network and a heterogeneous network when the mobility management protocol information is provided to the specific mobility management protocol. |
29. | The method of claim 22, further comprising establishing the network address for the at least one of a homogeneous network and a heterogeneous network. |
30. | A mobile terminal for receiving mobility management protocol information, the mobile terminal comprising: a unified interface to an upper layer of the mobile terminal for managing messages to and from at least one of a homogeneous network and a heterogeneous network; means for discovering an accessible link of the at least one of a homogeneous network and a heterogeneous network for performing handover; and means for informing the upper layer of the accessible link via the unified interface, wherein the means for informing the upper layer comprises means for providing the upper layer with mobility management protocol information of the at least one of a homogeneous network and a heterogeneous network prior to establishing a connection with the accessible link. |
31. | A mobile terminal for receiving mobility management protocol information, the mobile terminal comprising: a unified interface to an upper layer of the mobile terminal for managing messages to and from at least one of a homogeneous network and a heterogeneous network; means for establishing a connection with an accessible link of the at least one of a homogeneous network and a heterogeneous network for performing handover; and means for receiving in the upper layer information from the unified interface related to the established connection, wherein the means for receiving the information comprises means for receiving mobility management protocol information of the at least one of a homogeneous network and a heterogeneous network. |
32. | A mobile terminal for receiving mobility management protocol information, the mobile terminal comprising: a unified interface to an upper layer of the mobile terminal for managing messages to and from1 at least one of a homogeneous network and a heterogeneous network; means for establishing a connection with an accessible link of the at least one of a homogeneous network and a heterogeneous network for performing handover; and means for informing the upper layer of the established connection with the accessible link via the unified interface, wherein the means for informing the upper layer comprises means for providing the upper layer with mobility management protocol information of the at least one of a homogeneous network and a heterogeneous network. |
33. | A mobile terminal for receiving mobility management protocol information, the mobile terminal comprising: a unified interface to an upper layer of the mobile terminal for managing messages to and from at least one of a homogeneous network and a heterogeneous network; means for establishing a connection with an accessible link of the at least one of a homogeneous network and a heterogeneous network for performing handover; and means for receiving in the upper layer a request from the unified interface for establishing a network address for the at least one of a homogeneous network and a heterogeneous network, wherein the means for receiving a request for establishing a network address comprises means for providing the upper layer with mobility management protocol information of the at least one of a homogeneous network and a heterogeneous network. |
MOBILE TERMINAL FOR PERFORMING HANDOVER IN A MOBILE
COMMUNICATION SYSTEM
Technical Field
The present invention relates to a handover method
for a mobile terminal of a mobile communication system, and
more particularly to providing mobility management protocol
information to a multi-mode mobile terminal for performing
handover between heterogeneous networks.
Background Art
Currently, standards committee IEEE 802.21 conducts
intensive research into the international standards
associated with media independent handover (MIH) between
heterogeneous networks. MIH provides not only a seamless
handover but also a service continuity between the
heterogeneous networks, resulting in greater convenience
for a user who carries a mobile terminal. IEEE 802.21
defines a variety of functions (e.g., an MIH function, an
event service, a command service, and an information
service (IS) function) as basic requirements.
A mobile terminal (MSS) is indicative of a multi-mode
node for supporting at least two interface types. For
example, the multi-mode node can support a variety of
interface types, such as a wired interface type (also
called a wire-line interface type) such as the Ethernet
based on an IEEE 802.3 standard specification, a wireless
interface type based on IEEE 802.XX standard specifications
(e.g., IEEE 802.11, IEEE 802.15, IEEE 802.16), and other
interface types defined by a cellular standardization
organization (e.g., 3GPP or 3GPP2) .
A general Media Independent Handover Function (MIHF)
reference model is depicted in FIG. 1. In the figure, MIHF
architecture for interaction with other layers and with the
remote MIHG is illustrated. In order for the MIHF to
provide asynchronous and synchronous services to lower
layers and higher layers, Service Access Points (SAPs) such
as MIH_MGMT_SAP, MIH__SME__SAP and MIH_SAP along with
primitives are defined. MIH_MGMT_SAP defines the interface
between the MIHF and the management plane (Management
Entity) of different network interfaces and is used for
transporting MIH protocol messages between the MIHF and
local link layer entities as well as peer MIHF entities.
MIH_SAP defines the interface between the MIHF and higher
layer entities such as device manager, handover policy
control function, transport, layer 3 (L3) mobility
management protocol, etc., and is used for MIH
configuration and operation. MIH_SME_SAP defines the
interface between the MIHF and the Station Management
Entity or the Network Management System, and is used for
MIG configuration and operation.
FIG. 2 is a structural diagram illustrating a
protocol layer of a multi-mode mobile terminal. Referring
to FIG. 2, the protocol stack of the multi-mode mobile
terminal includes a MAC structure including the IEEE802.il,
the IEEE 802.16, and the 3G interface, and locates an MIH
function under an Internet protocol (IP) layer. A variety
of mobility management protocols are included in a network
layer contained in the mobile terminal. The mobile
terminal selects a mobility management protocol contained
in the network layer according to a mobility management
protocol type supported at a point of attachment (POA) to
which the mobile terminal is connected, and establishes an
IP connection.
The MIH function, an event service, a command service,
and an Information Service (IS) will hereinafter be
described.
Referring to FIG. 2, the multi-mode mobile terminal
includes a physical (PHY) layer, or a first layer (Ll) , and
' a Medium Access Control (MAC) layer, or a second layer (L2) ,
for individual modes, and locates the MIH layer under the
IP layer. The MIH function located under the IP layer,
i.e., the Media Independent Handover (MIH) must be defined
between IEEE 802-series interfaces, or between an IEEE 802-
series interface and a non-802-series interface (e.g., 3GPP
or 3GPP2) . The MIH function facilitates a handover process
using input values (e.g., a trigger event and information
associated with other networks) received from a second
layer (Layer 2) .
The MIH function may include a plurality of input
values based on both user policy and configuration which
may affect the handover process. General interfaces among
the mobile IP, a third layer (L3) entity such as an SIP
(Session Initiation Protocol) , and the MIH layer are
defined. In this case, the aforementioned interfaces
provide the first layer (i.e., the physical layer), the
second layer (i.e., the MAC layer), and mobility management
information. The MIH function acquires information
associated with a lower layer and a network using event and
information service (IS) functions.
An upper layer includes an upper management entity
for monitoring states and operations of various links
contained in a mobile terminal, such that it performs a
handover control function and a device manager function.
In this case, the handover control function and the device
manager may be located at different locations independent
of each other, or the handover control function and the
device manager may be included as the upper management
entities in the upper layer.
FIG. 3 shows an MIH structure and a transmission
protocol. In more detail, FIG. 3 shows a mobile terminal
function entity including the MIH function, a network
function entity, and a transmission protocol. Dotted lines
of FIG. 3 are indicative of primitive information and an
event trigger, etc.
In order to quickly perform a handover function, a
network layer uses information generated from a link layer
so that the network layer can quickly re-establish a
connection state. The link layer event is adapted to
predict the movement of a user, and helps a mobile terminal
and a network prepare the handover function.
A trigger for the handover may be initiated from the
physical (PHY) layer and the MAC layer. A source of the
trigger may be determined to be a local stack or a remote
stack. FIG. 4 is a block diagram illustrating a trigger
model.
An event trigger provides state information of a
current signal, state change information of another network,
and future predicted change information. The event trigger
further includes change information of the physical and MAC
layers or attribute change information of a specific
network .
The event types can be classified into a physical
(PHY) layer event, a MAC layer event, a management event, a
third layer (L3) event, and an application event, for
example. There are a plurality of basic trigger events,
such as a "Link__Up" event, a "Link__Down" event, a
"Link_Going_Down /y event, a "Link_Going_Up" event, a
"Link_Event_Rollback" event, a "Link_Available" event, a
"Link_Parameters_Change" event, an "IP_Renewal_Indication"
event, and an "IP Renewal_Request" event, for example. The
above-mentioned trigger events will hereinafter be
described with reference to the following tables.
The following Table 1 shows parameters of the
"LinkJJp" event.
The "LinkJJp" event occurs when a second layer (L2)
connection is established on a specific link interface and
an upper layer is able to transmit third layer (L3) packets.
In this case, it is determined that all L2 layers contained
in a link have been completely configured. A source of the
"LinkJJp" event corresponds to a "Local MAC" and a "Remote
MAC" .
[Table 1]
The following Table 2 shows parameters of the
'Link Down" event.
The "Link Down" event occurs when the L2 connection
is released on a specific interface and L3 packets cannot
be transmitted to a destination. The source of the
'Link Down" event is indicative of a local MAC.
[Table 2]
The following Table 3 shows parameters of the
"Link Going_Down" event.
The "Link_Going Down" event occurs when it is
expected that the L2 connection will enter a λN Link_Down"
state within a predetermined time, and may serve as a
signal for initializing a handover procedure. A source of
the "Link Going Down" corresponds to a "Local MAC" and a
x Remote MAC".
[Table 3]
The following Table 4 shows parameters of the
"Link Going Up" event.
The "Link_Going__Up" event occurs when it is expected
that the L2 connection will enter a "Link_Up" state within
a predetermined time, and is used when a long period of
time is consumed to initialize a network. A source of the
λλ Link_Going_Up" event corresponds to a "Local MAC" and a
"Remote MAC". . [Table 4]
The following Table 5 shows parameters of the
"Link_Event_Rollback" event.
The "Link_Event_Rollback" event is formed by
combining the "Link_Going_Down" event with the
"Link_Going_Up" event. The "Link_Event_Rollback" event is
indicative of a trigger generated when it is expected that
the "Link_Up" event or "Link_Down" event will not be
generated any more within a specific time on the condition
that the "Link_Going_Up" event or ΛN Link_Going_Down" event
are transmitted to a destination. A source of the
"Link Event Rollback" event corresponds to a Λλ Local MAC"
and a "Remote MAC".
[Table 5 ]
The following Table 6 shows parameters of the
"Link Available" event.
The Link Available" event is indicative of an
available state of a new specific link, and indicates the
possibility of allowing a new base station (BS) or a new
Point of Attachment (POA) to provide a link superior in
quality as compared to a current BS or a current POA to
which a current mobile terminal is connected. A source of
the "Link Available" event corresponds to a "Local MAC" and
v Remote MAC".
[Table 6]
The following Table 7 shows parameters of the
"Link Parameter Change" event.
The "Link_Parameter_Change" event is indicative of an
event generated when a change of a link parameter value is
higher than a specific threshold level. The
"Link_Parameter_Change" event includes link layer
parameters, for example, a link speed (i.e., a link rate),
a QoS (Quality of Service) , and an encrypted value, etc. A
source of the λΛ Link_Parameter_Change" event corresponds to
'Local MAC" and a "Remote MAC".
[Table 7]
The following Table 8 shows parameters of the
"IP_Renewal_Indication" event.
A new POA (e.g., a base station or POA) of the mobile
terminal receives the "Link_Up" trigger signal, and
triggers the "IP__Renewal_Indication" event to inform the
mobile terminal of a changed or unchanged state of an IP
address used for transmitting IP packets to the mobile
terminal. The IP address is set to a newly-assigned IP
address in the case of a dynamic host configuration
protocol (DHCP) system, to a new temporary address (CoA) in
the case of a mobile IPv4 system, and to an
Autoconfiguration address in the case of a mobile IPv6
system. A source of the Nλ IP_Renewal__Indication" event
corresponds to a "Remote MAC" and an "MIH".
[Table Eπ
Name Type Description
EventSource EVENT_ _LAYER_ TYPE Source at which event occurs
The following Table 9 shows parameters of the
'IP Renewal Request" event.
Upon receiving the "IP Renewal Indication" trigger
signal indicative of an address re-establishment state, the
MIH function of the mobile terminal transmits an
"IP_Renewal_Request" signal to a network layer, such that
it requests the network layer to re-establish an IP
temporary address. A source of the "IP Renewal Request"
event corresponds to a "Remote MAC" and an "MIH'
[Table 9]
FIG. 5 shows event triggers generated when a handover
occurs. In more detail, FIG. 5 exemplarily shows triggers
generated when a quality of a current access link is
deteriorated. The triggers are generated until a new link
is established.
A command service allows an upper layer to command a
lower layer to perform a predetermined operation. For
example, the upper layer transmits a specific command to
the MIH function such that the MIH function performs a
corresponding operation. The MIH function may also
transmit a specific command to the lower layer such that
the lower layer performs a corresponding operation. The
above-mentioned commands are adapted to transmit a decision
of the upper layer to the lower layer, and control the
behavior or tasks of lower layer entities.
An information service provides detailed information
associated with a network required for both network
discovery and network selection, and is designed to be
freely accessed by a user over any network. The
information service includes a variety of information
components, for example, a link access parameter, a
security mechanism, a neighborhood map, a location,
information indicative of a service provider and other
access information, and a link cost (i.e., cost of link).
FIG. 6 is a flow chart illustrating a method for
controlling a multi-mode mobile terminal to acquire
network-associated information via an information server.
As shown in FIG. 6, the multi-mode mobile terminal acquires
various network-associated information via the information
server, and performs a handover evaluation operation, a
link selection operation and a handover procedure.
In more detail, the multi-mode mobile terminal
receives an "Information Request/Response" message and a
"Response List of Available Networks" message. The multi-
mode terminal then acquires various network-associated
information from an information server via a current point
of attachment (POA) using the "Information
Request/Response" message and the "Response List of
Available Networks" message, such that the multi-mode
terminal performs a handover evaluation operation and a
link selection operation. If a new link is selected, the
mobile terminal acquires information associated with a new
network via the new point of attachment (POA) and an "MIH
Resource Query/Response" message.
A variety of protocols (e.g., Mobile IPv4, DHCPv4,
Mobile IPv6, and DHCPvβ, etc.) for supporting the mobility
of a mobile terminal will hereinafter be described.
FIG. 7 is a diagram illustrating operations of a
mobile IPv4 system. The mobile IPv4 system requires a
variety of functions (i.e., a mobile host function, a home
agent function and a foreign agent function) , such that it
can provide the upper layer with clear mobility. However,
if a path is not optimized, there is no need for a
correspondent node communicating with the mobile terminal
to be changed to another. In this case, the mobile host is
indicative of an IP host at which the mobility is supported.
The home agent maintains location information associated
with the mobile host, and .serves as a router for performing
tunneling of the mobile host. The foreign agent is
indicative of a router for supporting the mobility over a
foreign network.
Operations of the mobile IPv4 system shown in FIG. 7
will hereinafter be described. Referring to FIG. 7, the
mobile host moves from its home network to a foreign
network at step SlO. The mobile host then receives an
advertisement message currently broadcast over the foreign
network, such that mobile host recognizes that it has moved.
Thereafter, the mobile host registers a temporary address
or care of address (CoA) indicative of a current location
of the mobile host with the home agent (HA) at step S20.
In this case, the temporary address (CoA) may be equal to
an IP address (i.e., foreign agent (FA) - CoA) of the
foreign agent, or equal to a co-located CoA temporarily
assigned to the mobile host via the DHCP in the foreign
network.
Packets transmitted from an external part to the
mobile host are transmitted to the home network. These
packets are intercepted by the home agent at step S30,
which recognizes the movement of the mobile terminal. The
home agent having intercepted the above packets sets a
destination address of the packets transmitted to the
mobile host to an address of the foreign agent (FA) on the
condition that the FA-CoA is used. The mobile host then
encapsulates the destination address indicative of the FA
address and transmits the encapsulated address at step S40.
Thereafter, the encapsulated transmission packets are
transmitted to the foreign agent (FA) , wherein the foreign
agent (FA) de-capsulates the received packets to recover
original packets and transmits the original packets to the
mobile host at step S50.
Packets transmitted from the mobile host to the
correspondent node may be directly transmitted via the
foreign agent (FA) . If an ingress filtering problem
occurs, the above-mentioned packets may also be transmitted
via a reverse tunnel.
The principal functions required for the mobile IP
are an agent discovery function, a registration function,
and a routing function, etc., and their detailed
description will hereinafter be described.
Agent discovery is indicative of a method for
allowing a mobile terminal to determine whether the mobile
terminal is connected to its own home network or 'a foreign
network, such that the mobile terminal itself can recognize
whether it has moved to another network.
The mobile IP extends a conventional ICMP (Internet
" " Control Message Protocol) Router Discovery (i.e., IETF RFC
1256) to discover a desired agent. The agent advertisement
message periodically broadcast by the agents (i.e., home
agent and foreign agent) includes a "Mobility Agent
Advertisement Extension" message in an "ICMP Router
Advertisement" message, and transmits the "ICMP Router
Advertisement" message including the "Mobility Agent
Advertisement Extension" message. An "Agent Solicitation"
message transmitted when the mobile terminal searches for
an agent employs the same method as in a conventional "ICMP
Router Solicitation" message.
When the mobile terminal moves to another network, a
registration function transmits current location
information to the home agent, and allows the mobile
terminal to receive services from the home network without
any change, in such a way that a highly adaptable mechanism
is provided.
The mobile IP provides two registration procedures
(i.e., FA-CoA and co-located CoA), such that it can
establish a temporary address or care of address (CoA) when
the mobile terminal moves to another subnet. If the mobile
terminal uses the FA-CoA, it performs registration via the
foreign agent (FA) . If the mobile terminal uses the co-
located CoA, the mobile terminal directly performs
registration to the home agent. Also, if the FA-CoA is
used, the CoA is supplied from a foreign agent via an agent
advertisement message, and an IP address of the foreign
agent (FA) is used as a temporary address (CoA) . If the
co-located CoA is used, the mobile terminal receives a
temporary address (CoA) via a DHCP server located at the
foreign network.
A routing function defines a variety of functions
required for properly routing a datagram transmitted
to/received from the mobile terminal when the mobile
terminal is connected to or accesses a foreign network.
The datagram includes a unicast packet, a multicast packet,
and a broadcast packet.
A Dynamic Host Configuration Protocol (DHCP) is
indicative of a protocol which allows network managers to
centrally manage/allocate necessary IP addresses in a
network contained in their organization. When computer
users gain access to the Internet in an organization, an IP
address must be assigned to individual computers. When the
network manager centrally manages/allocates the IP address,
and a computer is connected to the Internet at points
outside the network, the DHCP automatically transmits a new
IP address to the computer.
The DHCP employs a rental (or lease) scheme for
controlling a given IP address. According to the scheme,
the given IP address is valid at a corresponding computer
only during a predetermined period of time. A lease time
may be changed according to an Internet access time
required by a user at a specific location. The DHCP
reduces the IP address lease time when many more computers
than available IP addresses are used, such that the DHCP
can dynamically reconstruct a network.
In order to correctly operate the DHCP, at least one
DHCP server and a single DHCP client is included in a
corresponding network. Also, the network must further
include not only the scope of a TCP/IP address (e.g.,
203.224.29.10 ~ 203.224.29.100) but also a gateway address
and a subnet mask.
The DHCP client acquires TCP/IP address information
from the DHCP server while in operation. However, it
should be noted that the acquired TCP/IP address is not
permanent. The DHCP server provides a client with a lease
address which may periodically expire or be periodically
updated.
The DHCP client acquires/maintains the lease address
via a plurality of handshake steps, each of which is
referred to as a state. There are a plurality of client
DHCP states, i.e., an initialization state (INT), a
selecting state (SELECTING) , a requesting state
(REQUESTING) , a binding state (BOUND) , a renewing state
(RENEWING), and a re-binding state (REBINDING), etc.
FIG. 8 shows a DHCP message format. FIG. 9 is a flow
chart illustrating operations of a DHCP client-server model,
and shows a method for allowing the DHCP client to
automatically receive an IP address from the DHCP server.
The following Table 10 shows various types and usages
of the DHCP messages shown in FIG. 9.
[Table 10]
DHCPINFORM Client to server, asking only for local configuration parameters; client already has externally configured network address.
FIG. 9 is a diagram illustrating operations of a
DHCPv4 system. Referring to FIG. 9, the DHCPvβ system is
indicative of a DHCP protocol for the IPv4 system.
Specifically, a method for controlling the DHCP client to
automatically receive an IP address from the DHCP server
will hereinafter be described with reference to FIG. 9 and
Table 10. First, the client broadcasts a "DHCPDISCOVER"
message at step SIlO. If individual servers receive the
"DHCPDISCOVER" message from the client, they answer the
received "DHCPDISCOVER" message and transmit a "DHCPOFFER"
message as a response signal at step S120.
The client having broadcast the "DHCPDISCOVER"
message receives the "DHCPOFFER" message from one or more
servers, and selects one of the servers to request a
configuration parameter. Thereafter, the client broadcasts
a "DHCPREQUEST" message at step S130. In this case,
servers not selected by the "DHCPREQUEST" message recognize
that the client has declined their respective offers. The
OU
server selected by the "DHCPREQUEST" message includes
address configuration information in a "DHCPACK" message,
and transmits the "DHCPACK" message with the address
configuration information as a response signal at step S140.
If the client receives the "DHCPACK" message from the
selected server, it constructs an address at step S150.
However, if the client receives a "DHCPNAK" message, the
client re-starts the aforementioned process. The client
may also transmit a "DHCPRELEASE" message to the server
when returning a leased address at step S160.
FIG. 10 is a flow chart illustrating operations of a
mobile IPv6 system. The mobile IPv6 system can more
effectively support mobility of a mobile terminal than the
mobile IPv4 system, and has superior extensibility. The
principal components for the mobile IPv6 system operations
and functions of individual principal components will
hereinafter be described with reference to FIG. 10.
Referring to FIG. 10,. a mobile node (MN) is a host or
router switching its network access. A correspondent node
(CN) is a host or router communicating with the mobile node
(MN) . A home agent (HA) acts as a router, and contains
registration information of the mobile node (MN) obtained
from other routers contained in a home network such that
the HA can transmit a datagram to a current position of the
mobile node (MN) contained in a foreign network. A
temporary address or care of address (CoA) is indicative of
an IP address connected to the mobile node when the mobile
node moves to a foreign node.
A term "Binding" is indicative of a specific
operation in which the mobile node matches the CoA
registered in the home agent with a home address of a
corresponding node. A "Binding Update (BU)" message is
indicative of a message used when the mobile node itself
informs the home agent (HA) and the correspondent node (CN)
of a CoA of the mobile node. A "Binding Acknowledge
(BACK) " message is indicative of a response message to the
aforementioned "BU" message. A "Binding Request (BR)"
message is indicative of a message for requesting the "BU"
message when the correspondent node (CN) does not receive
the "BU" message until a timer for the binding information
of the mobile node expires.
A term "CoA acquisition" is indicative of a specific
operation in which the mobile node automatically constructs
its location information while in motion using a neighbor
discovery function and an address auto-configuration
function. A term "Router Optimization" is indicative of a
specific procedure during which the correspondent node (CN)
directly communicates with the mobile node without passing
though the home agent after storing the binding information.
The above-mentioned address auto-configuration
function is classified into two address auto-configuration
methods. For example, a first method is a state-
maintenance-type address auto-configuration method for
acquiring an address using a server, such as the DHCP
server. A second method is a non-state-type address auto-
configuration method, wherein the mobile node controls a
host to generate an address by itself.
The state-maintenance-type address auto-configuration
method is adapted to assign one of a plurality of addresses
capable of being assigned from the server to the host on
the condition that the host requests an address from the
DHCP server. The non-state-type address auto-configuration
method combines the mobile node's interface ID information
with prefix information acquired from the router, such that
the mobile node forms an address.
Operations of the mobile IPv6 system shown in FIG. 10
will hereinafter be described. Referring to FIG. 10, if
the mobile node (MN) moves from a subnet A to another
subnet B at step S200, the mobile node (MN) recognizes that
it has moved to another subnet B using prefix information
of a Router Advertisement (RA) message and a Neighbor
ϋnreachable Detection (NUD) mechanism at step S210.
The mobile node (MN) itself then acquires a temporary
address or care of address (CoA) using the aforementioned
address auto-configuration method at step S220. Thereafter,
the mobile node (MN) transmits the "BU" message, such that
the home agent recognizes the acquired CoA at step S230.
The home agent (HA) having received the λX BU" message
combines (or binds) the home address of the mobile node
(MN) with a temporary address (CoA) , and transmits a "BACK"
message as a response signal to the Nλ BU" message at S240.
The correspondent node (CN) firstly communicating
with the mobile node (MN) does not recognize that the
mobile node (MN) has moved to another subnet. Accordingly,
the CN sets a destination address to a home address of the
mobile node (MN) , and transmits the resultant packet to the
home agent (HA) at step S250. The home agent (HA) for
managing the mobile node (MN) intercepts the packet of the
correspondent node (CN) , and performs tunneling of the
packet to a current location of the mobile node (MN) at
step S260.
If the mobile node (MN) receives the tunneled packet,
it determines that the correspondent node (CN) having
transmitted the packet does not have the binding
information, and transmits the XΛ BU" message to the
correspondent node (CN) , such that it informs the
correspondent node (CN) of a CoA of the mobile node (MN) at
step S270. The correspondent node (CN) having received the
CoA of the mobile node (MN) stores the binding information,
and directly communicates with the mobile node (MN) using
the binding information at step S280.
FIG. 11 is a flow chart illustrating operations of a
DHCPvβ system. Referring to FIG. 11, the DHCPvβ system is
indicative of a DHCP protocol for the IPv6, and supports
the state-maintenance-type address auto-configuration
method. The DHCPvβ system is indicative of a specific
mechanism by which an IP address, various information (e.g.,
routing information) , and a network resource management
function are concentrated on a small number of DHCP servers,
resulting in reduction of maintenance costs.
The DHCPvβ employs two multicast addresses, such as
an λλ All_DHCP_Relay_Agents_and_Servers" address and an
Λλ AllJDHCP_Servers" address. The
"All_DHCP_Relay_Agents_and_Servers" address is indicative
of a link local multicast address, which is used by a
client to allow the client to communicate with an agent
contained in a link on the condition that a link local
address of the agent is unknown. All servers and agents
act as components of the above multicast group.
The "All DHCP Servers" address is indicative of a
site local multicast address, which is used by a client or
a relay when the client or the relay transmits a message to
all servers or does not recognize unicast addresses of the
servers, such that the client or the relay can communicate
with a server. In order to allow the client to use the
above-mentioned "All_DHCP_Servers" address, the client must
have addresses of sufficient ranges at which the server
arrives. All servers contained in a site act as components
of the above-mentioned multicast group.
A variety of messages can be used for basic
operations of the DHCPvβ system, such as a "SOLICIT"
message, an "ADVERTISE" message, a "REQUEST" message, a
"REPLY" message, a "RENEW" message, and a "RELEASE" message,
for example.
The "SOLICIT" message is adapted for the client to
recognize location information of the server, and is
multitasked using the "All_DHCP_Servers" address. The
"ADVERTISE" message is indicative of a response message to
the "SOLICIT" message. If possible, the DHCP server
answers the "SOLICIT" message.
The "REQUEST" message is adapted to acquire
constituent parameters equipped with an IP address from the
server selected by the client, and is multitasked using the
"All_DHCP_Relay_Agents_and_Servers" address. The "REPLY"
message is indicative of a response message to the
aforementioned "REQUEST", "RENEW", and "RELEASE" messages.
The "RENEW" message is indicative of a message
required when the client acquires an initially-allocated
client address and the lifetime of the constituent
parameters. The "RELEASE" message is indicative of a
message required when the client returns at least one IP
address to the server.
Operations of the DHCPvβ system shown in FIG. 11 will
hereinafter be described. Referring to FIG. 11, the client
transmits the "SOLICIT" message to the "All_DHCP_Servers"
address to recognize location information of the server at
step S310. Individual DHCPvβ servers then output the
"ADVERTISE" message to answer the "SOLICIT" message at step
S320. In this case, the "ADVERTISE" message includes
prefix information.
Thereafter, the client selects one of the DHCPvβ
servers, transmits the "REQUEST" message to the selected
server, and at the same time requests an additional
constituent parameter at step S330. The selected DHCPvβ
server outputs the "REPLY" message to answer the "REQUEST"
message at step S340.
The client having received the "REPLY" message
transmits the "RENEW" message to the DHCPvβ server, such
that it updates conventional constituent parameters and the
lifetime of allocated addresses, and starts operation of a
Tl timer at step S350. In this case, the reference symbol
"Tl" is indicative of a specific time during which the
client accesses the server having acquired an old address
to increase the lifetime of a current address.
The DHCPvβ server transmits then the "REPLY" message
as a response signal to the "RENEW" message at step S360.
Thereafter, the client outputs the "RELEASE" message when
an allocated address is no longer used, such that a
corresponding address is released at step S370.
FIG. 12 is a flow chart illustrating an IP address
setup procedure. In more detail, the IP address setup
procedure indicates operations conducted when the multi-
mode mobile terminal is handed over to a new network, and a
mobility management protocol of the new network is
different from that of an old network.
Referring to FIG. 12, the old network supports the
mobility management protocol of the mobile IPv4 system.
The new network supports the mobility management protocol
of the mobile IPv6 system. It is assumed that the multi-
mode mobile terminal installs mobility management protocols
of the mobile IPv4 system and the mobile IPv6 system into a
stack.
If the multi-mode mobile terminal is handed over to a
new network, it receives an "IP_Renewal_Indication" trigger
signal, and performs a CoA re-establishment procedure. In
more detail, the mobile terminal having used the mobile
IPv4 as the mobility management protocol in an old network
broadcasts the "Agent Solicitation" message to acquire a
new CoA. However, the new network (to which the mobile
terminal is currently handed over) provides the mobile IPv6
as the mobility management protocol, such that the "Agent
Solicitation" message is discarded.
Accordingly, the mobile terminal does not receive an
"Agent Advertisement" message in response to the "Agent
Solicitation" message after a lifetime of the "Agent
Solicitation" message expires. After reattempting to
transmit the "Agent Solicitation" message several times,
the mobile terminal determines that it cannot be further
operated by the mobile IPv4, and performs a CoA setup
procedure using the mobile IPv6 message.
As described above, provided that the multi-mode
mobile terminal is handed over to a new interface network
(i.e., a new network), and a mobility management protocol
of an old network is different from that of the new network,
the mobile terminal requires a very long period of time
until it recognizes that it cannot be further operated by
the mobility management protocol of the old network in the
new network. Only then does the mobile terminal establish
a CoA using a mobility management protocol of the new
network. In other words, a Tengthy time delay occurs prior
to the mobile terminal determining that it cannot be
operated by the old mobility management protocol of the old
network in the new network and establishing a CoA using the
new mobility management protocol.
Therefore, due to the above-mentioned problems, the
mobile terminal for performing traffic
transmission/reception in real time encounters a damaged
packet and an extended service time.
Disclosure of Invention
The present invention is directed to providing
mobility management protocol information to a multi-mode
mobile terminal for performing handover between
heterogeneous networks.
Additional features and advantages of the invention
will be set forth in the description which follows, and in
part will be apparent from the description, or may be
learned by practice of the invention. The objectives and
other advantages of the invention will be realized and
attained by the structure particularly pointed out in the
written description and claims hereof as well as the
appended drawings .
To achieve these and other advantages and in
accordance with the purpose of the present invention, as
embodied and broadly described, the present invention is
embodied in a method for providing mobility management
protocol information to a mobile terminal, the method
comprising establishing a unified interface to an upper
layer of the mobile terminal for managing messages to and
from at least one of a homogeneous network and a
heterogeneous network, discovering an accessible link of
the at least one of a homogeneous network and a
heterogeneous network for performing handover, and
informing the upper layer of the accessible link via the
unified interface, wherein the step of informing the upper
layer comprises providing the upper layer with mobility
management protocol information of the at least one of a
homogeneous network and a heterogeneous network prior to
establishing a connection with the accessible link.
In one aspect of the invention, the method further
comprises requesting a scan of the at least one of a
homogeneous network and a heterogeneous network via the
unified interface to determine the presence of the
accessible link of the at least one of a homogeneous
network and a heterogeneous network for performing the
handover.
In another aspect of the invention, the method
further comprises requesting information related to the
accessible link of the at least one of a homogeneous
network and a heterogeneous network from an information
server operationally connected to the at least one of a
homogeneous network and a heterogeneous network.
Preferably, the step of requesting information
comprises requesting mobility management protocol
information of the at least one of a homogeneous network
and a heterogeneous network. Preferably, the unified
interface is a media independent handover function (MIHF)
entity. Preferably, the upper layer comprises an upper
management entity for managing homogeneous and
heterogeneous network- links associated with the mobile
terminal. Preferably, the upper layer comprises at least
one mobility management protocol for managing a respective
mobile terminal mobility method.
In accordance with another embodiment of the present
invention, a method for providing mobility management
protocol information to a mobile terminal comprises
establishing a unified interface to an upper layer of the
mobile terminal for managing messages to and from at least
one of a homogeneous network and a heterogeneous network,
establishing a connection with an accessible link of the at
least one of a homogeneous network and a heterogeneous
network for performing handover, and receiving in the upper
layer information from the unified interface related to the
established connection, wherein the step of receiving the
information comprises receiving mobility management
protocol information of the at least one of a homogeneous
network and a heterogeneous network.
Preferably, the step of receiving the information
comprises receiving in the upper layer a request from the
unified interface for establishing a network address for
the at least one of a homogeneous network and a
heterogeneous network, wherein the network address is an
Internet protocol (IP) address. Preferably, the unified
interface is a media independent handover function (MIHF)
entity. Preferably, the upper layer comprises an upper
management entity for managing homogeneous and
heterogeneous network links associated with the mobile
terminal. Preferably, the upper layer comprises at least
one mobility management protocol for managing a respective
mobile terminal mobility method.
In one aspect of the invention, the step of receiving
the information comprises providing the upper layer with
mobility management protocol information to a specific
mobility management protocol related to the information.
In another aspect of the invention, the method
further comprises providing the upper layer with mobility
management protocol information by providing the
information to a specific mobility management protocol
related to the information, and establishing the network
address for the at least one of a homogeneous network and a
heterogeneous network when the mobility management protocol
information is provided to the specific mobility management
protocol .
In a further aspect of the invention, the method
further comprises establishing the network address for the
at least one of a homogeneous network and a heterogeneous
network.
In accordance with another embodiment of the present
invention, a method for providing mobility management
protocol information to a mobile terminal comprises
establishing a unified interface to an upper layer of the
mobile terminal for managing messages to and from at least
one of a homogeneous network and a heterogeneous network,
establishing a connection with an accessible link of the at
least one of a homogeneous network and a heterogeneous
network for performing handover, and informing the upper
layer of the established connection with the accessible
link via the unified interface, wherein the step of
informing the upper layer comprises providing the upper
layer with mobility management protocol information of the
at least one of a homogeneous network and a heterogeneous
network .
Preferably, the unified interface is a media
independent handover function (MIHF) entity. Preferably,
the upper layer comprises an upper management entity for
managing homogeneous and heterogeneous network links
associated with the mobile terminal. Preferably, the upper
layer comprises at least one mobility management protocol
for managing a respective mobile terminal mobility method.
Preferably, the step of providing the upper layer with
mobility management protocol information comprises
providing the information to a specific mobility management
protocol related to the information.
In accordance with another embodiment of the present
invention, a method for providing mobility management
protocol information to a mobile terminal comprises
establishing a unified interface to an upper layer of the
mobile terminal for managing messages to and from at least
one of a homogeneous network and a heterogeneous network,
establishing a connection with an accessible link of the at
least one of a homogeneous network and a heterogeneous
network for performing handover, and receiving in the upper
layer a request from the unified interface for establishing
a network address for the at least one of a homogeneous
network and a heterogeneous network, wherein the step of
receiving a request for establishing a network address
comprises providing the upper layer with mobility
management protocol information of the at least one of a
homogeneous network and a heterogeneous network.
Preferably, the network address is an Internet
protocol (IP) address. Preferably, the unified interface
is a media independent handover function (MIHF) entity.
Preferably, the upper layer comprises an upper management
entity for managing homogeneous and heterogeneous network
links associated with the mobile terminal. Preferably, the
upper layer comprises at least one mobility management
protocol for managing a respective mobile terminal mobility
method.
In one aspect of the invention, the step of providing
the upper layer with mobility management protocol
information comprises providing the information to a
specific mobility management protocol related to the
information. Preferably, the method further comprises
establishing the network address for the at least one of a
homogeneous network and a heterogeneous network when the
mobility management protocol information is provided to the
specific mobility management protocol.
In another aspect of the invention, the method
further comprises establishing the network address for the
at least one of a homogeneous network and a heterogeneous
network.
In accordance with another embodiment of the present
invention, a mobile terminal for receiving mobility
management protocol information comprises a unified
interface to an upper layer of the mobile terminal for
managing messages to and from at least one of a homogeneous
network and a heterogeneous network, means for discovering
an accessible link of the at least one of a homogeneous
network and a heterogeneous network for performing handover,
and means for informing the upper layer of the accessible
link via the unified interface, wherein the means for
informing the upper layer comprises means for providing the
upper layer with mobility management protocol information
of the at least one of a homogeneous network and a
heterogeneous network prior to establishing a connection
with the accessible link.
In accordance with another embodiment of the present
invention, a mobile terminal for receiving mobility
management protocol information comprises a unified
interface to an upper layer of the mobile terminal for
managing messages to and from at least one of a homogeneous
network and a heterogeneous network, means for establishing
a connection with an accessible link of the at least one of
a homogeneous network and a heterogeneous network for
performing handover, and means for receiving in the upper
layer information from the unified interface related to the
established connection, wherein the means for receiving the
information comprises means for receiving mobility
management protocol information of the at least one of a
homogeneous network and a heterogeneous network. f→"
In accordance with another embodiment of the present
invention, a mobile terminal for receiving mobility
management protocol information comprises a unified
interface to an upper layer of the mobile terminal for
managing messages to and from at least one of a homogeneous
network and a heterogeneous network, means for establishing
a connection with an accessible link of the at least one of
a homogeneous network and a heterogeneous network for
performing handover, and means for informing the upper
layer of the established connection with the accessible
link via the unified interface, wherein the means for
informing the upper layer comprises means for providing the
upper layer with mobility management protocol information
of the at least one of a homogeneous network and a
heterogeneous network.
In accordance with another embodiment of the present
invention, a mobile terminal for receiving mobility
management protocol information comprises a unified
interface to an upper layer of the mobile terminal for
managing messages to and from at least one of a homogeneous
network and a heterogeneous network, means for establishing
a connection with an accessible link of the at least one of
a homogeneous network and a heterogeneous network for
performing handover, and means for receiving in the upper
layer a request from the unified interface for establishing
a network address for the at least one of a homogeneous
network and a heterogeneous network, wherein the means for
receiving a request for establishing a network address
comprises means for providing the upper layer with mobility
management protocol information of the at least one of a
homogeneous network and a heterogeneous network.
It is to be understood that both the foregoing
general description and the following detailed description
of the present invention are exemplary and explanatory and
are intended to provide further explanation of the
invention as claimed.
Brief Description of Drawings
In the drawings :
FIG. 1 illustrates a general media independent
handover function (MIHF) reference model.
FIG. 2 is a structural diagram illustrating a
protocol stack structure of a multi-mode mobile terminal.
FIG. 3 is a block diagram illustrating a media
independent handover (MIH) structure and a transmission
protocol .
FIG. 4 is a structural diagram illustrating a trigger
model.
FIG. 5 illustrates event triggers generated when a
handover operation occurs .
FIG. 6 is a flow chart illustrating a method for
allowing a multi-mode mobile terminal to acquire network-
associated information via an information server.
FIG. 7 is a diagram illustrating operations of a
mobile IPv4 system.
FIG. 8 is a structural diagram illustrating a Dynamic
Host Configuration Protocol (DHCP) message.
FIG. 9 is a flow chart illustrating operations of a
DHCP client-server model.
FIG. 10 is a flow chart illustrating operations of a
mobile IPv6 system.
FIG. 11 is a flow chart illustrating operations of a
DHCPvβ system.
FIG. 12 is a flow chart illustrating an Internet
protocol (IP) address setup procedure.
FIG. 13 is a structural diagram illustrating a "Link
Event" model and an "MIH Event" model in accordance with
one embodiment of the present invention.
FIG. 14 is a structural diagram illustrating a
"Remote Link Event" model in according with one embodiment
of the present invention.
FIG. 15 is a structural diagram illustrating a
"Remote MIH Event" model in accordance with one embodiment
of the present invention.
FIG. 16 is a structural diagram illustrating an "MIH
command" model and a "Link command" model in accordance
with one embodiment of the present invention.
FIG. 17 is a structural diagram illustrating a
"Remote MIH command" model in accordance with one
embodiment of the present invention.
FIG. 18 is a structural diagram illustrating a
"Remote Link Command" model in accordance with one
embodiment of the present invention.
FIG. 19 is a structural diagram illustrating a
protocol stack structure in accordance with one embodiment
of the present invention.
FIG. 20 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention.
FIG. 21 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention.
FIG. 22 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention.
FIG. 23 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention.
FIG. 24 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention.
FIG. 25 is a structural diagram illustrating a
protocol stack structure including an upper management
entity in accordance with one embodiment of the present
invention.
FIG. 26 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention.
FIG. 27 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention.
FIG. 28 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention.
FIG. 29 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention.
FIG. 30 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention.
FIG. 31 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention.
Best Mode for Carrying Out the Invention
The present invention relates to providing mobility
management protocol information to a multi-mode mobile
terminal for performing handover between heterogeneous
networks .
Reference will now be made in detail to the preferred
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings. Wherever
possible-, the same reference numbers will be used
throughout the drawings to refer to the same or like parts.
Prior to describing the present invention, it should
be noted that two methods are adapted to preferably provide
a mobile terminal with mobility management protocol
information supported by a new network. For example a
first method provides the mobile terminal with mobility
management protocol information via an event service, and a
second method provides the mobile terminal with mobility
management protocol information via an information service.
FIG. 13 is a structural diagram illustrating a "Local
Event" model and an "MIH Event" model in accordance with
one embodiment of the present invention. Referring to FIG.
13, the MIH event is indicative of an event transmitted
from the MIH to either the upper management entity or the
upper layer, and corresponds to conventional event triggers.
A link event is indicative of an event transmitted from a
lower layer (i.e., a MAC layer or a physical (PHY) layer)
to the MIH, and uses primitives for use in individual
interface MAC or physical layers.
FIG. 14 is a structural diagram illustrating a
"Remote Link Event" model in accordance with one embodiment
of the present invention. Referring to FIG. 14, if a lower
layer contained in a local stack generates an event and
transmits the event to the MIH contained in a local stack,
the MIH of the local stack transmits the aforementioned
event to the MIH of a remote stack.
FIG. 15 is a structural diagram illustrating a
"Remote MIH Event" model in accordance with one embodiment
of the present invention. Referring to FIG. 15, the MIH
function of the local stack generates a remote MIH event,
and transmits the remote MIH event to a correspondent MIH
function contained in a remote stack. The correspondent
MIH function transmits the received event to an upper
management entity or an upper layer contained in a stack of
the correspondent MIH function.
FIG. 16 is a structural diagram illustrating an "MIH
command" model and a "Link command" model in accordance
with one embodiment of the present invention. Referring to
FIG. 16, the MIH command is generated from the upper
management entity or the upper layer, and is then
transmitted to the MIH function, such that it commands the
MIH to perform a specific task. The link command is
generated from the MIH function, and is then transmitted to
the lower layer, such that it commands the lower layer to
perform a specific task.
FIG. 17 is a structural diagram illustrating a
"Remote MIH command" model in accordance with one
embodiment of the present invention. Referring to FIG. 17,
the remote MIH command is generated from the upper
management entity or the upper layer, and is then
transmitted to the MIH function. The MIH function
transmits the received MIH command to a correspondent MIH
function contained in a remote stack.
FIG. 18 is a structural diagram illustrating a
"Remote Link Command" model in accordance with one
embodiment of the present invention. Referring to FIG. 18,
the MIH function contained in the local stack generates a
remote link command, and transmits the remote link command
to a correspondent MIH function contained in a remote stack.
The correspondent MIH function transmits the remote link
command to the lower layer contained in the remote stack.
The following preferred embodiments of the present
invention relate to a method for providing a mobile
terminal with mobility management protocol information via
an event service. FIG. 19 is a structural diagram
illustrating a protocol stack structure in accordance with
one embodiment of the present invention. As shown in FIG.
19, if a multi-mode mobile terminal is handed over from an
IEEE 802.11 network (i.e., an old network) supporting a
mobile IPv4 as a mobility management protocol, to an IEEE
802.16 network (i.e., a new network) supporting an MlPvβ as
a mobility management protocol, a method for transmitting
mobility management protocol information supported by the
IEEE 802.16 network (i.e., the new network) uses the
inventive event service of the present invention using a
protocol stack structure.
If a mobile terminal acting as a multi-mode mobile
terminal is handed over to a new network, the Medium Access
Control (MAC) layer of the mobile terminal includes
mobility management protocol type information supported by
the new network in an MIH event (e.g., "Link_Available" or
"Link_Up") and transmits the MIH event equipped with the
mobility management protocol type information to an MIH
function (also called an MIH layer) . The MIH function then
transmits a "Link_Up" event to a corresponding mobility
management protocol (i.e., MIPv6) .
The method for providing the mobile terminal with the
mobility management protocol information via an event
service adds new parameters to the "Link_Up",
"Link Available" or "IP Renewal Indication" event in order
to provide the mobile terminal with new mobility management
protocol information supported by a new network.
Accordingly, the mobile terminal recognizes a mobility
management protocol supported by a new network via the
aforementioned newly-added parameters. The aforementioned
parameters include information associated with a current
mobility management protocol. However, if a new mobility
management protocol is to be developed in the future,
information associated with the newly developed mobility
management protocol may also be added to the aforementioned
parameters as necessary.
A newly-added parameter, such as a mobility
management protocol support type bitmap is indicative of
various mobility management protocol types capable of being
supported by the new network. For example, a bit of "1"
indicates that a corresponding mobility management protocol
can be supplied from a network.
FIG " . 20 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention. Preferably, a method for allowing the
mobile terminal to receive new mobility management protocol
information of a new network via a Λ% Link_Available" event
is shown. Referring to FIG. 20, if a mobile terminal
equipped with a mobile IPv4 mobility management protocol
and a mobile IPv6 mobility management protocol accesses a
network supporting the mobile IPv4 mobility management
protocol, and is then handed over to a new network
supporting the mobile IPv6 mobility management protocol, a
mobility management protocol support type bitmap of the
present invention is contained in the λλ Link_Available"
event. Accordingly, a mobility management protocol type
supported by the new network is supplied to the mobile
terminal before the mobile terminal establishes a
connection state with the new network (i.e., new link).
Preferably, a new lower layer (LL new) or new MAC
layer of the multi-mode mobile terminal acquires mobility
management protocol information (e.g., mobile IPv6) of a
new point of attachment (POA) using a scanning operation
and other messages. The LL new then includes the acquired
information in the "Link Available" event and transmits the
"Link_Available" event including the acquired information
to the MIH layer.
Accordingly, if the MIH layer receives a "Link_Up"
event indicating that the mobile terminal has established a
connection setup with a corresponding link when the MIH
layer temporarily maintains the mobility management
protocol information associated with a corresponding point
of attachment (POA) , the MIH layer transmits a "Link_Up
MIH" event to a corresponding mobility management protocol
(i.e., mobile IPv6) by referring to the aforementioned
maintained information. Thereafter, an upper layer or
network layer of the mobile terminal performs an IPv6 Care
of Address (CoA) setup procedure to acquire a new CoA, and
registers the new CoA with a home agent.
The following table 11 exemplarily shows parameters
of the λλ Link_Available" event including the mobility
management protocol support type bitmap.
[Table 11]
Name Type Description
EventSource EVENT _LAYER_ TYPE Source at which event occurs
FIG. 21 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention. Preferably, a method for allowing a
mobile terminal to receive mobility management protocol
information of a new network via the "Link_Up" event is
shown in FIG. 21.
Preferably, as shown in FIG. 21, if a mobile terminal
equipped with a mobile Ipv4 mobility management protocol
and a mobile IPv6 mobility management protocol accesses a
network capable of supporting the mobile IPv4 mobility
management protocol, and is then handed over to a new
network supporting the mobile IPv6 mobility management
protocol, a mobility management protocol support type
bitmap of the present invention is contained in the
"Link_Up" event. Accordingly, a mobility management
protocol type supported by the new network is supplied to
the mobile terminal before a network layer handover
procedure is executed.
Preferably, a new lower layer (LL New) , such as a MAC
layer, of the multi-mode mobile terminal establishes a
connection state with a new link via a "Link establishment
Request/Response" message, such that the LL New acquires
mobility management protocol information (e.g., MlPvβ) of a
new point of attachment (POA) . Thereafter, if the multi-
mode mobile terminal establishes a connection state with
the new link, a λΛ Link__Up MIH" event including the mobility
management protocol information is transmitted to the MIH
layer. The MIH layer then transmits a corresponding event
service to a corresponding mobility management protocol
(MlPvβ) by referring to the mobility management protocol
support type bitmap of the trigger "Link_Up" event.
The following Table 12 exemplarily shows parameters
of the "Link_Up" event including the mobility management
protocol support type bitmap.
[Table 12]
FIG. 22 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention. Preferably, a method for allowing a
mobile terminal to receive mobility management protocol
information of new network via the
'IP Renewal Indication" event is shown in FIG. 22.
Preferably, as shown in FIG. 22, if a mobile terminal
equipped with a mobile Ipv4 mobility management protocol
and a mobile IPv6 mobility management protocol accesses a
network capable of supporting the mobile IPv4 mobility
management protocol, and is then handed over to a new
network supporting the mobile IPv6 mobility management
protocol, the mobility management protocol support type
bitmap of the present invention is contained in the
"IP_Renewal_Indication" event. Accordingly, a mobility
management protocol type supported by the new network is
supplied to the mobile terminal before the network layer
handover procedure is executed.
Preferably, a new point of attachment (POA) of the
mobile terminal receives a "Remote Link_Up MIH" event from
the mobile terminal. The new POA then transmits an
λλ IP_Renewal_Indication Link" event, including mobility
management protocol information supplied from a network of
the mobile terminal, to the MIH layer of the mobile
terminal. The MIH layer of the mobile terminal then
transmits an λλ IP_Renewal_Request" event to a corresponding
mobility management protocol (MlPvβ) by referring to the
mobility management protocol support type bitmap of the
Λλ IP_Renewal_Indication Link" event.
The above-mentioned preferred embodiment shows an
example in which the "IP_Renewal_Indication" trigger signal
occurs after a link setup between the mobile terminal and
the new point of attachment (POA) is completed. However,
provided that the old point of attachment (POA) acquires IP
address information of the new point of attachment (POA)
using an inter-MIH signal message (i.e., a signal message
between MIH functions) , the old POA can provide the
aforementioned "IP_Renewal_Indication" trigger signal
before the mobile terminal establishes a link with the new
POA.
The following Table 13 exemplarily shows parameters
of the λλ IP Renewal Indication" event including the mobility-
management protocol support type bitmap.
[Table 13]
FIG. 23 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention. Preferably, a method for allowing a
mobile terminal to receive mobility management protocol
information of a new network via the information service is
shown in FIG. 23.
Referring to FIG. 23, in accordance with one
embodiment of the present invention, a parameter similar to
the aforementioned mobility management protocol support
type bitmap is contained in a "Query (Response) List of
Available Networks" message (i.e., a signal message between
the MIH of the mobile terminal and the MIH of the current
point of attachment (POA) or access point) , such that the
mobile terminal can receive mobility management protocol
information supported by a corresponding network.
FIG. 24 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention. Preferably, a method for allowing a
mobile terminal to receive mobility management protocol
information of a new network via the information service is
shown in FIG. 24.
Referring to FIG. 24, in accordance with one
embodiment of the present invention, a parameter similar to
the aforementioned mobility management protocol support
type bitmap is contained in a λN Query More (Response) Info on
802. y Networks" message (i.e., a signal message between the
MIH of the mobile terminal and the MIH of the current point
of attachment (POA) or access point), such that the mobile
terminal can receive mobility management protocol
information supported by a corresponding network.
FIG. 25 is a structural diagram illustrating a
protocol stack structure including an upper management
entity in accordance with one embodiment of the present
invention. Referring to FIG. 25, if a multi-mode mobile
terminal is handed over from an IEEE 802.11 network (i.e.,
an old network) supporting a mobile IPv4 mobility
management protocol to an IEEE 802.16 network (i.e., a new
network) supporting an MlPvβ mobility management protocol,
a method for transmitting mobility management protocol
information supported by the aforementioned IEEE 802.16
network (i.e., the new network) using the inventive event
service of the present invention is depicted in FIG. 25
using a protocol stack structure.
If a mobile terminal acting as a multi-mode mobile
terminal is handed over to a new network, the MAC layer of
the mobile terminal includes mobility management protocol
type information supported by the new network in a
predetermined event (e.g., "Link_Available" or λλ Link_ϋp") ,
and transmits the event equipped with the aforementioned
mobility management protocol type information to an upper
management entity. The upper management entity then
transmits the Nλ Link_Up" event to a corresponding mobility
management protocol (i.e., MlPvβ) .
The method for providing the mobile terminal with the
mobility management protocol information via an event
service adds new parameters to the "Link_Up",
Λλ Link_Available" or "IP_Renewal_Indication" event in order
to provide the mobile terminal with new mobility management
protocol information supported by a new network. The
mobile terminal recognizes a mobility management protocol
supported by a new network via the aforementioned newly-
added parameters. The aforementioned parameters include
information associated with a current mobility management
protocol 1 . However, if a new mobility management protocol
is to be developed in the future, associated information
may also be added to the aforementioned parameters as
necessary.
The newly-added parameter (i.e., a mobility
management protocol support type bitmap) is indicative of
various mobility management protocol types capable of being
supported by the new network. A bit of λλ l" indicates that
a corresponding mobility management protocol can be
supplied from a network.
FIG. 26 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention. Preferably, as shown in FIG. 26, if a
mobile terminal equipped with a mobile Ipv4 mobility
management protocol and a mobile IPv6 mobility management
protocol accesses a network capable of supporting the
mobile IPv4 mobility management protocol, and is then
handed over to a new network for supporting the mobile IPv6
mobility management protocol, a mobility management
protocol support type bitmap of the present invention is
contained in a "Link_Available MIH" event. Accordingly, a
mobility management protocol type supported by the new
network is supplied to the mobile terminal before the
mobile terminal establishes a connection state with the new
network (i.e., new link). In accordance with the preferred
embodiment shown in FIG. 26, the upper management entity
includes an upper layer (e.g., L3 and above), a device
manager, and a handover control function.
Preferably, a new lower layer (LL New) , such as a new
MAC layer, of the multi-mode mobile terminal acquires
mobility management protocol information (e.g., mobile
IPv6) of a new point of attachment (POA) using a scanning
operation and other messages. The new MAC layer includes
the acquired information in a "Link_Available MIH" event,
and transmits the λλ Link_Available MIH" event including the
acquired information to the upper management entity via the
MIH function. Preferably, the upper management entity
transmits mobility management protocol information
associated with a corresponding point of attachment (POA)
to the upper layer, such that it commands the corresponding
mobility management protocol (i.e., mobile IPv6) to enter a
λλ Link_Up" state. Thereafter, a network layer of the mobile
terminal performs an IPv6 Care of Address (CoA) setup
procedure to acquire a new CoA, and registers the new CoA
with a home agent.
FIG. 27 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention. Preferably, a method for allowing the
mobile terminal to receive mobility management protocol
information associated with a new network via a "Link_Up"
event is shown in FIG. 27.
Preferably, as shown in FIG. 27, if a mobile terminal
equipped with a mobile Ipv4 mobility management protocol
and a mobile IPv6 mobility management protocol accesses a
network capable of supporting the mobile IPv4 mobility
management protocol, and is then handed over to a new
network supporting the mobile IPv6 mobility management
protocol, a mobility management protocol support type
bitmap of the present invention is contained in the
"Link_Up" event. Accordingly, a mobility management
protocol type supported by the new network is supplied to
the mobile terminal before the network layer handover
procedure is executed. In accordance with the preferred
embodiment shown in FIG. 26, the upper management entity
includes an upper layer (e.g., L3 and above), a device
manager, and a handover control function.
Preferably, a new lower layer (LL New) , such as a new
MAC layer, of the multi-mode mobile terminal establishes a
connection state with a new link via a "Link establishment
Request/Response" message, such that it acquires mobility
management protocol information (e.g., MIPv6) of a new
point of attachment (POA) .
Thereafter, if the multi-mode mobile terminal
establishes a connection state with the new link, the
"Link__Up MIH" event including the mobility management
protocol information is transmitted to the MIH layer. The
MIH layer then transmits a corresponding event service to a
corresponding mobility management protocol (MlPvδ) by
referring to the mobility management protocol support type
bitmap of the trigger "Link_Up" event.
FIG. 28 is a flow chart illustrating an- IP address
setup procedure in accordance with one embodiment of the
present invention. Preferably, a method for allowing the
mobile terminal to receive mobility management protocol
information associated with a new network via an
"IP_Renewal_Indication" event is shown in FIG. 28.
Preferably, as shown in FIG. 28, if a mobile terminal
equipped with a mobile Ipv4 mobility management protocol
and a mobile IPv6 mobility management protocol accesses a
network capable of supporting the mobile IPv4 mobility
management protocol, and is then handed over to a new
network supporting the mobile IPv6, a mobility management
protocol support type bitmap of the present invention is
contained in the "IP Renewal_Indication" event.
Accordingly, a mobility management protocol type supported
by the new network is supplied to the mobile terminal
before the network layer handover procedure is executed.
In accordance with the preferred embodiment shown in FIG.
28, the upper management entity includes an upper layer
(e.g., L3 and above), a device manager, and a handover
control function.
Preferably, a new point of attachment (POA) of the
mobile terminal receives a "Remote Link_Up MIH" event from
the mobile terminal. The new POA then transmits an
λλ IP_Renewal_Indication Link" event, including mobility
management protocol information supplied from a network of
the mobile terminal, to the upper management entity. The
upper management entity then transmits an
λλ IP_Renewal_Request" event to a corresponding mobility
management protocol (MlPvδ) by referring to the mobility
management protocol support type bitmap of the
"IP_Renewal_Indication Link" event.
The above-mentioned preferred embodiment shows an
example in which the λλ IP_Renewal_Indication" trigger signal
occurs after a link setup between the mobile terminal and a
new point of attachment (POA) is completed. However,
provided that the old POA acquires IP address information
of the new POA using an inter-MIH signal message (i.e., a
signal message between MIH functions) , the old POA can
provide the aforementioned "IP_Renewal_Indication" trigger
signal before the mobile terminal establishes a link with
the new POA.
FIG. 29 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention. Preferably, a method for allowing the
mobile terminal to receive mobility management protocol
information associated with a new network via an
information service is shown in FIG. 29.
As shown in FIG. 29, a parameter similar to the
aforementioned mobility management protocol support type
bitmap is contained in a "Query (Response) List of Available
Networks" message (i.e., a signal message between the MIH
of a mobile terminal and the MIH of a current point of
attachment (POA) or access point) , and is then transmitted
to an upper management entity, such that the upper
management entity can receive mobility management protocol
information supported by a corresponding network.
FIG. 30 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention. Preferably, a method for allowing the
mobile terminal to receive mobility management protocol
information associated with a new network via the
information service is shown in FIG. 30.
As shown in FIG. 30, a parameter similar to the
aforementioned mobility management protocol support type
bitmap is contained in a "Query More (Response) Info on
802. y Networks" message (i.e., a signal message between the
MIH of the mobile terminal and the MIH of the current point
of attachment (POA) or access point) , and is then
transmitted to an upper management entity, such that the
upper management entity can receive mobility management
protocol information supported by a corresponding network.
FIG. 31 is a flow chart illustrating an IP address
setup procedure in accordance with one embodiment of the
present invention. Referring to FIG. 31, similar to the
aforementioned preferred embodiment of FIG. 28, although
the mobility management protocol type information is
contained in an λN IP_Renewal_Indication" trigger signal, the
"IP_Renewal__Indication" trigger signal occurs after the
mobile terminal transmits a remote λX Link_Going__Down"
trigger signal to an old POA. The old POA receives the
remote "Link_Going_Down" trigger signal from the mobile
terminal, acquires IP-associated information associated
with a new POA by the inter-MIH signal message, includes
the acquired IP-associated information in the
"IP_Renewal_Indication" trigger signal, and finally
transmits the λλ IP_Renewal_Indication" trigger signal
including the new POA' s IP-associated information to the
mobile terminal.
Although the above-mentioned preferred embodiments of
the present invention use the mobile IPv4 and the mobile
IPv6 mobility management protocols as examples, it should
be noted that the scope or spirit of the present invention
is not limited to only the mobile IPv4 and the mobile IPv6,
and is also applicable to other examples and modifications.
As apparent from the above description, a handover
method for a mobile communication system according to the
present invention previously provides a mobile terminal
with mobility management protocol information supported by
a new network via an event service or an information
service, when a multi-mode mobile terminal equipped with a
plurality of mobility management protocols is handed over
to a new interface network.
Therefore, the present invention greatly reduces a
delay time consumed while the mobile terminal recognizes
that it cannot be further operated by an old mobility
management protocol of an old network in the new network,
and establishes a Care of Address (CoA) using a new
mobility management protocol of the new network, such that
the new CoA can be quickly established without generating a
damaged packet and an extended service time.
Although the present invention is described in the
context of mobile communication, the present invention may
also be used in any wireless communication systems using
mobile devices, such as PDAs and laptop computers equipped
with wireless communication capabilities. Moreover, the
use of certain terms to describe the present invention
should not limit the scope of the present invention to
certain type of wireless communication system, such as UMTS.
The present invention is also applicable to other wireless
communication systems using different air interfaces and/or
physical layers , for example, TDMA, CDMA, FDMA, WCDMA, etc.
The preferred embodiments may be implemented as a
method, apparatus or article of manufacture using standard
programming and/or engineering techniques to produce
software, firmware, hardware, or any combination thereof.
The term "article of manufacture" as used herein refers to
code or logic implemented in hardware logic (e.g., an
integrated circuit chip, Field Programmable Gate Array
(FPGA), Application Specific Integrated Circuit (ASIC),
etc.) or a computer readable medium (e.g., magnetic storage
medium (e.g., hard disk drives, floppy disks, tape, etc.),
optical storage (CD-ROMs, optical disks, etc.), volatile
and non-volatile memory devices (e.g., EEPROMs, ROMs, PROMs,
RAMs, DRAMs, SRAMs, firmware, programmable logic, etc.).
Code in the computer readable medium is accessed and
executed by a processor. The code in which preferred
embodiments are implemented may further be accessible
through a transmission media or from a file server over a
network. In such cases, the article of manufacture in
which the code is implemented may comprise a transmission
media, such as a network transmission line, wireless
transmission media, signals propagating through space,
radio waves, infrared signals, etc. Of course, those
skilled in the art will recognize that many modifications
may be made to this configuration without departing from
the scope of the present invention, and that the article of
manufacture may comprise any information bearing medium
known in the art.
It will be apparent to those skilled in the art that
various modifications and variations can be made in the
present invention without departing from the spirit or
scope of the inventions. Thus, it is intended that the
present invention covers the modifications and variations
of this invention provided they come within the scope of
the appended claims and their equivalents.
The foregoing embodiments and advantages are merely
exemplary and are not to be construed as limiting the
present invention. The present teaching can be readily
applied to other types of apparatuses. The description of
the present invention is intended to be illustrative, and
not to limit the scope of the claims. Many alternatives,
modifications, and variations will be apparent to those
skilled in the art. In the claims, means-plus-function
clauses are intended to cover the structure described
herein as performing the recited function and not only
structural equivalents but also equivalent structures.
Industrial Applicability
The present invention can be applied to communication
systems using mobile devices, such as PDAs and laptop
computers equipped with wireless communication capabilities.
The present invention is also applicable to other wireless
communication systems using different air interfaces and/or
physical layers, for example, TDMA, CDMA, FDMA, WCDMA, etc..