WO2007138056A1 - Method for increasing handoff speed of mobile node in wireless lan and the mobile node - Google Patents

Method for increasing handoff speed of mobile node in wireless lan and the mobile node Download PDF

Info

Publication number
WO2007138056A1
WO2007138056A1 PCT/EP2007/055202 EP2007055202W WO2007138056A1 WO 2007138056 A1 WO2007138056 A1 WO 2007138056A1 EP 2007055202 W EP2007055202 W EP 2007055202W WO 2007138056 A1 WO2007138056 A1 WO 2007138056A1
Authority
WO
WIPO (PCT)
Prior art keywords
access point
mobile node
handoff
service set
set identifier
Prior art date
Application number
PCT/EP2007/055202
Other languages
French (fr)
Inventor
Ling Chen
Original Assignee
Siemens Aktiengesellschaft
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens Aktiengesellschaft filed Critical Siemens Aktiengesellschaft
Priority to EP07729623A priority Critical patent/EP2022212A1/en
Publication of WO2007138056A1 publication Critical patent/WO2007138056A1/en

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/14—Reselecting a network or an air interface
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0011—Control or signalling for completing the hand-off for data sessions of end-to-end connection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/24—Reselection being triggered by specific parameters
    • H04W36/32—Reselection being triggered by specific parameters by location or mobility data, e.g. speed data
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/10—Small scale networks; Flat hierarchical networks
    • H04W84/12—WLAN [Wireless Local Area Networks]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0083—Determination of parameters used for hand-off, e.g. generation or modification of neighbour cell lists
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/08—Reselecting an access point

Definitions

  • the present invention relates to mobile IP technology, in particular, to a method for increasing handoff speed of mobile node in wireless LAN and the mobile node.
  • the mobile IP usually serves as the network layer protocol and the IP is used to provide the user mobility management.
  • the so-called mobile IP technology means that the mobile node is allowed to use the same IP address throughout a number of subnets on the IP network, and to perform instantaneous roaming in the internet and local area network without any limitation. In other words, with the fixed network IP address, the mobile node may perform the roaming function across different network sections, and guarantee that the network authority based on network IP remains unchanged during the roaming performance.
  • a transmitting network is always divided into a number of separate subnets each of which has its own address field (address and mask) . Therefore, the handoffs below may occur during the roaming of the mobile node in the network:
  • Micro handoff also called handoff within subnet, i.e., the mobile node attaches to the same subnet before and after the handoff. Thus, it is not necessary for the mobile node to vary its care-of address.
  • Macro handoff which is handoff within area, representing the handoff of the mobile node between two access points (AP) located in different IP subnets. It is required to update the care-of address of said mobile node after handoff.
  • This process is defined in the mobile IP, comprising the processes of: mobile detection, DHCP (Dynamic Host Configuration Protocol) , stateless IP configuration (only in IPv6) , DAA (duplicate address detection) , neighbor discovery (only in IPv6) and rebinding/re-associating etc.
  • Global handoff which is handoff between areas, representing the handoff of mobile node between two different internet areas. Besides the operation of address update, authentication, authorization and etc, it is also needed to perform the operation of conversation reconfiguration, when the mobile node enters into a new access area.
  • the mobile node shall perform different operation with regard to whether there is need for updating the care-of address. Moreover, the terminal must determine whether there is macro handoff occurred simultaneously when it detects that micro handoff occurs because said macro handoff occurs in IP layer in practice. Thus, the mobile node is required to determine the type of handoff before performing such handoff.
  • the standard mobile IP periodically sends routing announcement (RA) message through the router to perform mobile detection, with the routing information of the links (including the subnet information) carried in the RA message.
  • RA routing announcement
  • the mobile node After receiving the RA, the mobile node detects the subnet information in said message, and determines to perform macro handoff if the received subnet information is different from the respective value in the previous message.
  • the mobile node can also send routing request (RS) message to trigger the mobile agent to send the RA.
  • RS routing request
  • the RA is multicasted every 1-lOS, and there is no effective scheme for triggering the mobile node to send RS in the standard mobile IP.
  • the standard mobile IP would cause a relative long delay (1-lOS) during the handoff.
  • the mobile node may be instructed to trigger macro handoff by the layer 2 modules in the mobile node during the micro handoff in the existing extended mobile IP scheme.
  • the mobile node when its link layer has been detected to handoff to a new link, the mobile node sends RS message to router B on the new link. After receiving this request, router B returns a RA message based on which the mobile node determines whether to trigger the layer 3 handoff. If the layer 3 handoff needs to be triggered, the process of CoA (care-of address) updating and DAD (Duplicate Address Detection) with router B is performed, and then the process of address binding with the home agent of router B. Upon accomplishment of the binding, it may achieve normal data transmission through the home agent .
  • CoA care-of address
  • DAD Downlicate Address Detection
  • This scheme avoided the delay of mobile node waiting for RA message after the link layer handoff, and hence increased the handoff speed to a certain extent.
  • this handoff scheme can perform the above process only after accomplishment of the link layer handoff which introduces a determination delay.
  • the handoff result may not be optimal because the link layer handoff is completely independent of network layer handoff.
  • said handoff scheme increases the communication volume and mobile IP operations in the network. Furthermore, this would also lead to unnecessary transmission delay and packet loss because the probability of micro handoff is by far greater than that of macro handoff in most cases.
  • the primary object of the present invention is to provide a method for increasing handoff speed of mobile node in wireless LAN to overcome the shortcoming of the presence of relative large delay during macro handoff of mobile node, so as to increase the handoff speed of mobile node in wireless LAN.
  • Another object of the present invention is to provide a type of mobile node with guaranteed handoff speed and handoff quality.
  • a method for increasing handoff speed of a mobile node in wireless LAN comprising:
  • said step of determining handoff mode and a new access point comprises:
  • the mobile node acquiring a candidate access point list containing service set identifier information and signal strength information
  • said step of mobile node acquiring a candidate access point list comprises:
  • the mobile node sending probe request message to all the RF channels; and creating the access point list based on the received probe response message of the RF channels.
  • said method further comprises: setting the service set identifier structure as STD@TPID.VTD, wherein SID is the identifier string of service, IPID is the identifier string of the IP subnet and VID is the identifier string of the service provider .
  • IPID is a 40 bit integer when representing the IPv4 subnet, wherein the first 32 bits represent the IPv4 address, and the later 8 bits represent the subnet mask length;
  • IPID is a 136 bit integer when representing the IPv6 subnet, wherein the first 128 bits represent the IPv6 address and the later 8 bits represent the prefix length.
  • Said step of determining the handoff mode and a new access point based on service set identifier information in the access point list comprises:
  • Said step of determining the position of each access point relative to said mobile node based on said service set identifier information comprises:
  • the access point of said service set identifier in the access point list is located in the same subnet as the mobile node;
  • the access point of said service set identifier in the access point list is located in the same area as the mobile node.
  • a mobile node comprises:
  • An access point information storage module for storing candidate access point list information containing service set identifier information and signal strength information
  • An access point selection module connected with said access point information storage module, for determining the handoff mode and a new access point based on said access point list information when the mobile node needs handoff;
  • Handoff performing module connected with handoff mode and access point selection module for performing handoff to said new access point based on the determined handoff mode.
  • said mobile node further comprises:
  • An access point information acquiring module connected with said access point information storage module for acquiring the information corresponding to each access point based on the response message of the access point received by the mobile node .
  • said mobile node further comprises:
  • a service set identifier storage module for storing the service set identifier information of the mobile node
  • a comparison module respectively connected with said access point information storage module and said service set identifier storage module for comparing the service set identifier information in said access point list with the service set identifier information of the mobile node and informing the comparison result to said access point selection module .
  • the present invention first ascertains the handoff mode and the new access point needed to perform when the mobile node needs handoff.
  • the micro handoff mode may be preferably selected to perform handoff in the case of a plurality of handoff possibility, so as to reduce the probability of macro handoff and hence the unnecessary service and computation cost.
  • the present invention makes use of the fact that SSID (service set identifier) exists in many messages in 802.11 MAC management protocol and can be obtained in the initial stage of the link layer handoff (handoff detection stage) to designate SSID to represent the value of IP subnet in which the AP is located.
  • SSID service set identifier
  • the mobile node can obtain in advance the network layer information of the selected AP during the link layer handoff detection, so as to facilitate the succeeding handoff process.
  • the present invention sets the SSID structure as "service identifier string @ IP subnet identifier string. service provider identifier string" so as to allow the mobile node to predict the handoff mode of candidate AP during the handoff and accordingly make optimal selection among a number of selected links. Thus, it can effectually increase the handoff speed and handoff efficiency of mobile node in wireless LAN by using the present invention .
  • Figure 1 is a flow chart of macro handoff of mobile IPv6 performed through the second layer triggering in the prior art.
  • Figure 2 is a flow chart implementing an example according to the present invention.
  • Figure 3 is a flow chart implementing micro handoff according to the method of the present invention.
  • Figure 4 is a flow chart implementing macro handoff according to the method of the present invention.
  • Figure 5 is a flow chart implementing global handoff according to the method of the present invention.
  • Figure 6 is a theoretical block diagram of an example according to the mobile node of the present invention.
  • the key feature of the present invention is to first determine the handoff mode needs to be performed and a new access point so as to allow a mobile node directly perform corresponding handoff operation when the mobile node needs handoff. Furthermore, micro handoff mode is preferably selected to perform handoff in the case of a number of handoff possibilities.
  • the present invention designates SSID to represent the value of the IP subnet in which the access point is located, makes the mobile subnet to obtain the network layer information of the selected access point during link layer handoff detection, and determines the handoff mode needs to performed and the new access point.
  • the present invention sets the SSID structure as "service identifier string @ IP subnet identifier string, service provider identifier string" so as to allow the mobile node to make optimal selection among a number of selected links based on SSID information.
  • Figure 2 shows the implementing flow of an example according to the method of the present invention. It comprises:
  • Step 201 the mobile node obtaining candidate access point list containing SSID information and signal strength information, when it needs handoff.
  • the mobile node During the mobilization process, the mobile node continually detects the current link quality, such as signal strength, error code ratio and etc. When the current link quality has decreased to an unacceptable threshold, the mobile node begins to send a Probe Request message on all the RF channels, in order to find out available services.
  • the access points which have received the Probe Request message respond to the mobile node with the Probe Response message containing SSID information.
  • the mobile node can create a candidate access point list based on the received Probe Response message, and write the information, such as SSID information, signal strength, etc, to said list with each list item corresponding to the information of one access point.
  • the access point list may have different forms as needed, for example, it may create two lists containing SSID information and signal strength information respectively, and preferably select a suitable access point in the list containing SSID information to perform handoff .
  • Step 202 determining the handoff mode and a new access point based on the SSID information in the access point list.
  • SSID is used to distinguish different networks, or in simple words, SSID is a name for local area network. In IPv4, SSID may have a maximum of 32 characters usually carried in the control information of the MAC (media access control) layer protocol.
  • SSID is defined as the value of IP subnet, i.e. SSID is expressed using IP subnet value.
  • the subnet address may be repeatedly used in the IPv4 network, for example, when a private IP address is used in the IP subnet, it is possible for adjacent access points with the same subnet value to belong to different subnet. Thus, in the IPv4 network, it is not sufficient to detect macro handoff by simply using the IP subnet value.
  • the present invention further sets the SSID structure as SID@IPID.
  • VID wherein SID is a service identifier string representing "audio”, “video” and etc, IPID is an IP subnet identifier string, and VID is a service provider identifier string such as "cnc", "Unicom”, etc. Based on the SSID information with this type of structure, the mobile node can make optimal selection among a number of selected links.
  • IPID is a 40 bit integer for an IPv4 subnet, wherein the first 32 bits represent the IPv4 address and the later 8 bits represent the subnet mask length, whereas IPID is a 136 bits integer for the IPv6 subnet, wherein the first 128 bits represent the IPv6 address and the later 8 bits represent the prefix length.
  • the SSID information of the access point may be configured according to the above structure.
  • the position of each access point in the candidate access point list may be determined relative to the mobile node as follows:
  • the access point of said service set identifier in the access point list is located in the same subnet as the mobile node;
  • the access point of said service set identifier in the access point list is located in a different area from the mobile node.
  • the access point located in the same subnet as the mobile node is preferably selected to perform micro handoff, so as to decrease the probability of macro handoff. If there is no access point in the access point list located in the same subnet as the mobile node, the access point located in the same area as the mobile node is selected to perform macro handoff. If there is no access point in the access point list located in the same area as the mobile node, the access point with the strongest signal strength is selected based on the signal strength to perform global handoff.
  • Step 203 performing handoff to the new access point based on the determined handoff mode.
  • the existing layer 2 network device usually provides the function of address learning with liner speed.
  • the data transmission of layer 2 would resume immediately after the handoff of the terminal.
  • the terminals need to perform complicated processes in the case of macro handoff, for example, if it maintains its own IP address unchanged across the IP subnet, the IP network is required to be capable of modifying in time the related routing in the transmission path, so as to re-build the data transmission path.
  • the present invention preferably selects micro handoff to perform rather than selects the new access point only based on the signal strength as in the prior art, so as to decrease the probability of macro handoff, and thus to increase the handoff speed effectively.
  • the area handoff usually requires the mobile node to accomplish the new access (authorization) process.
  • the mobile node may get to know whether it needs to perform global handoff at the very beginning of the handoff. If the global handoff is needed, it may duly initiate the access authorization process, and thus reduces the delay and packet loss in the handoff.
  • the handoff process of the mobile node according to the method of present invention will further be illustrated by way of examples .
  • Example 1 it is supposed that the SSID stored by the mobile node is VolP@ (192.168.1.0 : 24 ⁇ . cnc, the SSID configuration of access point A is VoIPt? (192.168.1.0:24) . cnc, and the SSID configuration of access point B is WEB@ (192.168.2.0 : 24) .unicorn.
  • the mobile node sends a Probe Request message to all the RF channels to perform a scan process when it needs handoff.
  • the mobile node discovers two access points: access point A and access point B.
  • the mobile node obtains the SSID information "VoIPg ( 192.168.1.0:24) . cnc" corresponding to access point A from the Probe Response message issued in reply by said access point A, and puts it into the candidate access point list; and obtains the SSID information "WEB@ ( 192.168.2.0 : 24 ) . unicorn" corresponding to access point B from the Probe Response message issued in reply by said access point B, and puts it into the candidate access point list.
  • the mobile node After comparing with its own stored SSID information, the mobile node preferably selects access point A as the new access point to perform micro handoff.
  • the re-association process is performed.
  • the mobile node sends an Auth . Request (authentication request) message to access point A, and access point A responds with an Auth .Response (authentication response) message to the mobile node after receiving said request message.
  • the mobile node sends a Re-association Request message to access point A, and access point A responds with a Re-association Response message to the mobile node to complete the handoff process after receiving said request message.
  • the mobile node sets up a data service with access point A.
  • Example 2 it is supposed that the SSID stored by the mobile node is VoIP@ (192.168.1.0 : 24) . cnc, and the SSID configuration of access point C is VoIP@ ( 192.168.2.0 : 24 ) , cnc .
  • Figure 4 the SSID stored by the mobile node is VoIP@ (192.168.1.0 : 24) . cnc, and the SSID configuration of access point C is VoIP@ ( 192.168.2.0 : 24 ) , cnc .
  • Figure 4 As shown in Figure 4 :
  • the mobile node sends a Probe Request message to all the RF channels to perform a scan process when it needs handoff .
  • the mobile node discovers access point C.
  • the mobile node obtains the SSID information "VoTP@ (192.168.2.0:24 ⁇ , cnc" corresponding to access point C from the Probe Response message issued in reply by said access point C, and puts it into the candidate access point list.
  • the mobile node selects access point C as the new access point to perform macro handoff.
  • the mobile node performs an authentication process and Re-association process with access point C:
  • the mobile node sends an Auth. Request (authentication request) message to access point C, and access point C responds with an Auth .Response (authentication response) message to the mobile node after receiving said request message.
  • the mobile node sends a Re-association Request message to access point C, and access point C responds with a Re-association Response message to the mobile node after receiving said request message.
  • the macro handoff process is triggered once the authentication is passed and re-association with access point C is built.
  • the access point router re-assigns an IP address for the mobile node by either stateful DHCPv4/6 (Dynamic Host Configuration Protocol) address assignment process or stateless address assignment process of neighbor discovery protocol.
  • the process of DHCPv4/6 comprises: the terminal sending a message discovered by the DHCP service, and the DHCP server responding to the discovered message. Then the terminal sends an address request message, and the server assigns an IP address for the terminal based on its own condition and returns confirmation. After the accomplishment of the assignment, the terminal and the server maintain the address assignment state with their respective timers, and refresh the process to guarantee the validity of the assignment if overtime occurs.
  • the mobile node After the new access point assigns an IP address for the mobile node, the mobile node performs mobile IP re-binding and re- association process with the mobile agent of the access point.
  • the mobile node sets up a data service with access point C.
  • Example 3 it is supposed the SSID stored by the mobile node is VoTP@ ( 192.166.1.0 : 24 ) . cnc, 5 and the SSID configuration of access point D is VoTP6 (192.168.1.0:24) . un icom . As shown in Figure 5 :
  • the mobile node sends a Probe Request message to all the RF channels to perform a scan process when it needs handoff.
  • the mobile node discovers access point D.
  • the mobile node obtains the SSID information "VoTPC d ( ' 192. ' 1 b8. ' 1.0:24) . uni com" corresponding to access point D from the Probe Response message issued in reply by said access point D, and puts it into the candidate access point list.
  • the mobile node selects access point D as the new access point, triggering the global handoff process.
  • the mobile node performs an authentication process and Re-association process with access point D:
  • the mobile node sends an Auth. Request (authentication request) message to access point D, and access point D responds with an Auth .Response (authentication response) message to the mobile node after receiving said request message.
  • the mobile node sends a Re-association Request message to access point D, and access point D responds with a Re-association Response message to the mobile node after receiving said request message.
  • the access point router re-assigns an IP address for the mobile node by either a stateful DHCPv4/6 address assignment process or stateless address assignment process of neighbor discovery protocol.
  • the process of DHCPv4/6 comprises: the terminal sending a message discovered by a DHCP service, and the DHCP server responding to the discovered message. Then the terminal sends an address request message, and the server assigns an IP address for the terminal based on its own condition and returns confirmation. After the accomplishment of the assignment, the terminal and the server maintain the address assignment state with their respective timers, and refresh the process to guarantee the validity of the assignment if overtime occurs. As both sides need to maintain the state machine, this type of assignment is stateful.
  • the stateless address assignment only exists in IPv6, a process in which the terminal finds out the prefix of the subnet the port is located in through neighbor discovery protocol, and then generates an IPv6 address based on the prefix .
  • the mobile node After the new access point assigns an IP address for the mobile node, the mobile node performs mobile IP re-binding and re- association process with the mobile agent of the access point.
  • the mobile node comprises an access point information storage module SOl for storing a candidate access point list information containing service set identifier information and signal strength information, an access point selection module S02 for determining handoff mode and a new access point based on the access point list information when the mobile node needs handoff, and a handoff performing module S03 for performing handoff to the new access point based on the determined handoff mode .
  • SSID service set identifier
  • IP subnet IP subnet
  • the present invention further sets the SSID structure as SIDQlPID .
  • VID wherein SID is service identifier string representing "audio”, “video”, etc, IPID is an IP subnet identifier string, and VID is a service provider identifier string such as "cnc", "Unicom”, etc. Based on the SSID information with this type of structure, the mobile node can make optimal selection among a number of selected links.
  • IPID is a 40 bit integer for the IPv4 subnet, wherein the first 32 bits represent the IPv4 address and the later 8 bits represent the subnet mask length, whereas IPID is a 136 bit integer for the IPv6 subnet, wherein the first 128 bits represent the IPv6 address and the later 8 bits represent the prefix length.
  • the SSID information of the access point may be configured according to the above structure.
  • candidate access point information In order to obtain candidate access point information, in the present example, it is through the access point information acquiring module S04 to obtain candidate access point information including the information of SSID, signal strength, etc. corresponding to the access point.
  • the SSID information can be obtained through messages such as a Beacon message or a Probe Response message in mobile IP, and be sent to access point information storage module SOl to set up the relation between access point and its corresponding service set identifier and signal strength.
  • the access point selection module S02 determines the preferred access point to perform the corresponding handoff operation based on the information stored in the access point storage module, such as service set identifier information or signal strength, or collective consideration of both service set identifier and signal strength.
  • the mobile node of the present invention further comprises: a service set identifier storage module S05 for storing the service set identifier information of the mobile node, and a comparison module S06 respectively connected with the access point information storage module SOl and the service set identifier storage module S05 for comparing the service set identifier information in the access point list with the service set identifier information of the mobile node and informing the comparison result to the access point selection module S02.
  • the access point selection module S02 determines the new access point based on the comparison result.
  • the selection of a new access point and the particular handoff process of the mobile node of the present invention are similar to those in the description of the method of the present invention, and will not be described with unnecessary details.

Abstract

The present invention discloses a method for increasing handoff speed of a mobile node in wireless LAN, which comprises determining the handoff mode and a new access point when the mobile node needs handoff and performing handoff to the new access point based on the determined handoff mode. The present invention further discloses a mobile node, which comprises an access point information storage module, an access point selection module, and a handoff performing module. The handoff speed of the mobile node in wireless LAN can be effectively improved by using the present invention.

Description

Method for increasing handoff speed of mobile node in wireless LAN and the mobile node
Technical field
The present invention relates to mobile IP technology, in particular, to a method for increasing handoff speed of mobile node in wireless LAN and the mobile node.
Background
Recently network operators have been setting up Broad Band Wireless Access Networks through WLAN (Wireless Local Area Network) . In the WLAN, the mobile IP usually serves as the network layer protocol and the IP is used to provide the user mobility management. The so-called mobile IP technology means that the mobile node is allowed to use the same IP address throughout a number of subnets on the IP network, and to perform instantaneous roaming in the internet and local area network without any limitation. In other words, with the fixed network IP address, the mobile node may perform the roaming function across different network sections, and guarantee that the network authority based on network IP remains unchanged during the roaming performance. In the frame structure of existing IP networks, a transmitting network is always divided into a number of separate subnets each of which has its own address field (address and mask) . Therefore, the handoffs below may occur during the roaming of the mobile node in the network:
1. Micro handoff, also called handoff within subnet, i.e., the mobile node attaches to the same subnet before and after the handoff. Thus, it is not necessary for the mobile node to vary its care-of address.
2. Macro handoff, which is handoff within area, representing the handoff of the mobile node between two access points (AP) located in different IP subnets. It is required to update the care-of address of said mobile node after handoff. This process is defined in the mobile IP, comprising the processes of: mobile detection, DHCP (Dynamic Host Configuration Protocol) , stateless IP configuration (only in IPv6) , DAA (duplicate address detection) , neighbor discovery (only in IPv6) and rebinding/re-associating etc.
3. Global handoff, which is handoff between areas, representing the handoff of mobile node between two different internet areas. Besides the operation of address update, authentication, authorization and etc, it is also needed to perform the operation of conversation reconfiguration, when the mobile node enters into a new access area.
In the handoff process, the mobile node shall perform different operation with regard to whether there is need for updating the care-of address. Moreover, the terminal must determine whether there is macro handoff occurred simultaneously when it detects that micro handoff occurs because said macro handoff occurs in IP layer in practice. Thus, the mobile node is required to determine the type of handoff before performing such handoff.
In the prior art, the standard mobile IP periodically sends routing announcement (RA) message through the router to perform mobile detection, with the routing information of the links (including the subnet information) carried in the RA message. After receiving the RA, the mobile node detects the subnet information in said message, and determines to perform macro handoff if the received subnet information is different from the respective value in the previous message. The mobile node can also send routing request (RS) message to trigger the mobile agent to send the RA.
The RA is multicasted every 1-lOS, and there is no effective scheme for triggering the mobile node to send RS in the standard mobile IP. Thus, the standard mobile IP would cause a relative long delay (1-lOS) during the handoff.
In order to speed up the mobile detection and reduce the handoff delay, the mobile node may be instructed to trigger macro handoff by the layer 2 modules in the mobile node during the micro handoff in the existing extended mobile IP scheme.
As shown in Figure 1, when its link layer has been detected to handoff to a new link, the mobile node sends RS message to router B on the new link. After receiving this request, router B returns a RA message based on which the mobile node determines whether to trigger the layer 3 handoff. If the layer 3 handoff needs to be triggered, the process of CoA (care-of address) updating and DAD (Duplicate Address Detection) with router B is performed, and then the process of address binding with the home agent of router B. Upon accomplishment of the binding, it may achieve normal data transmission through the home agent .
This scheme avoided the delay of mobile node waiting for RA message after the link layer handoff, and hence increased the handoff speed to a certain extent. However, this handoff scheme can perform the above process only after accomplishment of the link layer handoff which introduces a determination delay. In addition, the handoff result may not be optimal because the link layer handoff is completely independent of network layer handoff. On the other hand, said handoff scheme increases the communication volume and mobile IP operations in the network. Furthermore, this would also lead to unnecessary transmission delay and packet loss because the probability of micro handoff is by far greater than that of macro handoff in most cases.
Summary of the invention
The primary object of the present invention is to provide a method for increasing handoff speed of mobile node in wireless LAN to overcome the shortcoming of the presence of relative large delay during macro handoff of mobile node, so as to increase the handoff speed of mobile node in wireless LAN.
Another object of the present invention is to provide a type of mobile node with guaranteed handoff speed and handoff quality.
For these purposes, the present invention provides the following technical solution:
A method for increasing handoff speed of a mobile node in wireless LAN, comprising:
Determining the handoff mode and a new access point when the mobile node needs handoff;
Performing handoff to the new access point based on the determined handoff mode.
Preferably, said step of determining handoff mode and a new access point comprises:
The mobile node acquiring a candidate access point list containing service set identifier information and signal strength information;
Determining the handoff mode and the new access point based on the service set identifier information in the access point list.
Preferably, said step of mobile node acquiring a candidate access point list comprises:
The mobile node sending probe request message to all the RF channels; and creating the access point list based on the received probe response message of the RF channels.
Preferably, said method further comprises: setting the service set identifier structure as STD@TPID.VTD, wherein SID is the identifier string of service, IPID is the identifier string of the IP subnet and VID is the identifier string of the service provider . IPID is a 40 bit integer when representing the IPv4 subnet, wherein the first 32 bits represent the IPv4 address, and the later 8 bits represent the subnet mask length;
IPID is a 136 bit integer when representing the IPv6 subnet, wherein the first 128 bits represent the IPv6 address and the later 8 bits represent the prefix length.
Said step of determining the handoff mode and a new access point based on service set identifier information in the access point list comprises:
Determining the position of each access point relative to said mobile node based on said service set identifier information;
Preferably selecting an access point located in the same subnet as said mobile node to perform micro handoff;
Selecting an access point located in the same area as said mobile node to perform macro handoff if there is no access point in said access point list located in the same subnet as said mobile node;
Selecting the access point with strongest signal based on said signal strength to perform global handoff if there is no access point in said access point list located in the same area as said mobile node.
Said step of determining the position of each access point relative to said mobile node based on said service set identifier information comprises:
If all the SID, IPID and VID fields of the service set identifier in the access point list are identical to the SID, IPID and VID fields of the service set identifier stored by said mobile node, the access point of said service set identifier in the access point list is located in the same subnet as the mobile node;
If the SID and IPID fields of the service set identifier in the access point list are different from the SID and IPID fields of the service set identifier stored by said mobile node, and the VID fields are identical, the access point of said service set identifier in the access point list is located in the same area as the mobile node.
A mobile node comprises:
An access point information storage module for storing candidate access point list information containing service set identifier information and signal strength information;
An access point selection module connected with said access point information storage module, for determining the handoff mode and a new access point based on said access point list information when the mobile node needs handoff; and
Handoff performing module connected with handoff mode and access point selection module for performing handoff to said new access point based on the determined handoff mode.
Preferably, said mobile node further comprises:
An access point information acquiring module connected with said access point information storage module for acquiring the information corresponding to each access point based on the response message of the access point received by the mobile node .
Preferably, said mobile node further comprises:
A service set identifier storage module for storing the service set identifier information of the mobile node;
A comparison module respectively connected with said access point information storage module and said service set identifier storage module for comparing the service set identifier information in said access point list with the service set identifier information of the mobile node and informing the comparison result to said access point selection module .
It can be seen from the technical solution provided by the present invention that the present invention first ascertains the handoff mode and the new access point needed to perform when the mobile node needs handoff. As a result, the micro handoff mode may be preferably selected to perform handoff in the case of a plurality of handoff possibility, so as to reduce the probability of macro handoff and hence the unnecessary service and computation cost. In order to make the needed handoff known by the mobile node at the beginning of the handoff, the present invention makes use of the fact that SSID (service set identifier) exists in many messages in 802.11 MAC management protocol and can be obtained in the initial stage of the link layer handoff (handoff detection stage) to designate SSID to represent the value of IP subnet in which the AP is located. In this manner, the mobile node can obtain in advance the network layer information of the selected AP during the link layer handoff detection, so as to facilitate the succeeding handoff process. In view of the fact that the subnet address may be repeatedly used in the IPv4 network, the present invention sets the SSID structure as "service identifier string @ IP subnet identifier string. service provider identifier string" so as to allow the mobile node to predict the handoff mode of candidate AP during the handoff and accordingly make optimal selection among a number of selected links. Thus, it can effectually increase the handoff speed and handoff efficiency of mobile node in wireless LAN by using the present invention .
Description of the figures
Figure 1 is a flow chart of macro handoff of mobile IPv6 performed through the second layer triggering in the prior art.
Figure 2 is a flow chart implementing an example according to the present invention.
Figure 3 is a flow chart implementing micro handoff according to the method of the present invention.
Figure 4 is a flow chart implementing macro handoff according to the method of the present invention.
Figure 5 is a flow chart implementing global handoff according to the method of the present invention.
Figure 6 is a theoretical block diagram of an example according to the mobile node of the present invention. Embodiment
The key feature of the present invention is to first determine the handoff mode needs to be performed and a new access point so as to allow a mobile node directly perform corresponding handoff operation when the mobile node needs handoff. Furthermore, micro handoff mode is preferably selected to perform handoff in the case of a number of handoff possibilities. In order to make known the needed handoff mode by the mobile node at the very beginning of the handoff, the present invention designates SSID to represent the value of the IP subnet in which the access point is located, makes the mobile subnet to obtain the network layer information of the selected access point during link layer handoff detection, and determines the handoff mode needs to performed and the new access point. In view of the fact that the subnet address may be repeatedly used in the IPv4 network, the present invention sets the SSID structure as "service identifier string @ IP subnet identifier string, service provider identifier string" so as to allow the mobile node to make optimal selection among a number of selected links based on SSID information.
The present invention will be described in further detail with reference to the accompanying figures and exemplary embodiments to make the solution of the present invention better understood for those skilled in the art.
Reference is made to Figure 2 which shows the implementing flow of an example according to the method of the present invention. It comprises:
Step 201: the mobile node obtaining candidate access point list containing SSID information and signal strength information, when it needs handoff.
During the mobilization process, the mobile node continually detects the current link quality, such as signal strength, error code ratio and etc. When the current link quality has decreased to an unacceptable threshold, the mobile node begins to send a Probe Request message on all the RF channels, in order to find out available services. The access points which have received the Probe Request message respond to the mobile node with the Probe Response message containing SSID information. Thus, the mobile node can create a candidate access point list based on the received Probe Response message, and write the information, such as SSID information, signal strength, etc, to said list with each list item corresponding to the information of one access point.
The access point list may have different forms as needed, for example, it may create two lists containing SSID information and signal strength information respectively, and preferably select a suitable access point in the list containing SSID information to perform handoff .
Step 202: determining the handoff mode and a new access point based on the SSID information in the access point list.
It is well understood for those skilled in the art that SSID is used to distinguish different networks, or in simple words, SSID is a name for local area network. In IPv4, SSID may have a maximum of 32 characters usually carried in the control information of the MAC (media access control) layer protocol.
In order to allow the mobile node to determine the handoff needs to be performed, in the present invention, SSID is defined as the value of IP subnet, i.e. SSID is expressed using IP subnet value. In consideration that the subnet address may be repeatedly used in the IPv4 network, for example, when a private IP address is used in the IP subnet, it is possible for adjacent access points with the same subnet value to belong to different subnet. Thus, in the IPv4 network, it is not sufficient to detect macro handoff by simply using the IP subnet value. In view of the above, the present invention further sets the SSID structure as SID@IPID. VID, wherein SID is a service identifier string representing "audio", "video" and etc, IPID is an IP subnet identifier string, and VID is a service provider identifier string such as "cnc", "Unicom", etc. Based on the SSID information with this type of structure, the mobile node can make optimal selection among a number of selected links.
IPID is a 40 bit integer for an IPv4 subnet, wherein the first 32 bits represent the IPv4 address and the later 8 bits represent the subnet mask length, whereas IPID is a 136 bits integer for the IPv6 subnet, wherein the first 128 bits represent the IPv6 address and the later 8 bits represent the prefix length.
The SSID information of the access point may be configured according to the above structure.
By using this particular structure of SSID, the position of each access point in the candidate access point list may be determined relative to the mobile node as follows:
(1) If all the SID, IPID and VID fields of the service set identifier in the access point list are identical to the SID, IPID and VID fields of service set identifier stored by said mobile node, the access point of said service set identifier in the access point list is located in the same subnet as the mobile node;
(2) If the SID and VID fields of the service set identifier in the access point list are different from the SID and VID fields of service set identifier stored by said mobile node, and the IPID fields are identical, the access point of said service set identifier in the access point list is located in the same area as the mobile node;
(3) Otherwise, the access point of said service set identifier in the access point list is located in a different area from the mobile node. For the above three cases, the access point located in the same subnet as the mobile node is preferably selected to perform micro handoff, so as to decrease the probability of macro handoff. If there is no access point in the access point list located in the same subnet as the mobile node, the access point located in the same area as the mobile node is selected to perform macro handoff. If there is no access point in the access point list located in the same area as the mobile node, the access point with the strongest signal strength is selected based on the signal strength to perform global handoff.
Step 203: performing handoff to the new access point based on the determined handoff mode.
It is understood by those skilled in the art that, for micro handoff, the existing layer 2 network device (exchange) usually provides the function of address learning with liner speed. Thus, the data transmission of layer 2 would resume immediately after the handoff of the terminal. In comparison with micro handoff, the terminals need to perform complicated processes in the case of macro handoff, for example, if it maintains its own IP address unchanged across the IP subnet, the IP network is required to be capable of modifying in time the related routing in the transmission path, so as to re-build the data transmission path. It can be seen from the description according to the method of the present invention, in the case of a number of handoff modes to select, the present invention preferably selects micro handoff to perform rather than selects the new access point only based on the signal strength as in the prior art, so as to decrease the probability of macro handoff, and thus to increase the handoff speed effectively. Moreover, during the global handoff process, the area handoff usually requires the mobile node to accomplish the new access (authorization) process. By using the method of the present invention, the mobile node may get to know whether it needs to perform global handoff at the very beginning of the handoff. If the global handoff is needed, it may duly initiate the access authorization process, and thus reduces the delay and packet loss in the handoff.
The handoff process of the mobile node according to the method of present invention will further be illustrated by way of examples .
Example 1: it is supposed that the SSID stored by the mobile node is VolP@ (192.168.1.0 : 24 } . cnc, the SSID configuration of access point A is VoIPt? (192.168.1.0:24) . cnc, and the SSID configuration of access point B is WEB@ (192.168.2.0 : 24) .unicorn.
As shown in Figure 3 :
The mobile node sends a Probe Request message to all the RF channels to perform a scan process when it needs handoff. During the scan process, the mobile node discovers two access points: access point A and access point B. The mobile node obtains the SSID information "VoIPg ( 192.168.1.0:24) . cnc" corresponding to access point A from the Probe Response message issued in reply by said access point A, and puts it into the candidate access point list; and obtains the SSID information "WEB@ ( 192.168.2.0 : 24 ) . unicorn" corresponding to access point B from the Probe Response message issued in reply by said access point B, and puts it into the candidate access point list. After comparing with its own stored SSID information, the mobile node preferably selects access point A as the new access point to perform micro handoff.
Firstly, the re-association process is performed. The mobile node sends an Auth . Request (authentication request) message to access point A, and access point A responds with an Auth .Response (authentication response) message to the mobile node after receiving said request message. The mobile node sends a Re-association Request message to access point A, and access point A responds with a Re-association Response message to the mobile node to complete the handoff process after receiving said request message. After that, the mobile node sets up a data service with access point A.
Example 2: it is supposed that the SSID stored by the mobile node is VoIP@ (192.168.1.0 : 24) . cnc, and the SSID configuration of access point C is VoIP@ ( 192.168.2.0 : 24 ) , cnc . As shown in Figure 4 :
The mobile node sends a Probe Request message to all the RF channels to perform a scan process when it needs handoff . During the scan process, the mobile node discovers access point C. The mobile node obtains the SSID information "VoTP@ (192.168.2.0:24} , cnc" corresponding to access point C from the Probe Response message issued in reply by said access point C, and puts it into the candidate access point list. After comparing with its own stored SSID information, the mobile node selects access point C as the new access point to perform macro handoff.
Firstly, the mobile node performs an authentication process and Re-association process with access point C:
The mobile node sends an Auth. Request (authentication request) message to access point C, and access point C responds with an Auth .Response (authentication response) message to the mobile node after receiving said request message. The mobile node sends a Re-association Request message to access point C, and access point C responds with a Re-association Response message to the mobile node after receiving said request message.
The macro handoff process is triggered once the authentication is passed and re-association with access point C is built. The access point router re-assigns an IP address for the mobile node by either stateful DHCPv4/6 (Dynamic Host Configuration Protocol) address assignment process or stateless address assignment process of neighbor discovery protocol. The process of DHCPv4/6 comprises: the terminal sending a message discovered by the DHCP service, and the DHCP server responding to the discovered message. Then the terminal sends an address request message, and the server assigns an IP address for the terminal based on its own condition and returns confirmation. After the accomplishment of the assignment, the terminal and the server maintain the address assignment state with their respective timers, and refresh the process to guarantee the validity of the assignment if overtime occurs. As both sides need to maintain the state machine, this type of assignment is stateful. The stateless address assignment only exists in IPv6, a process in which the terminal finds out the prefix of the subnet the port is located in through neighbor discovery protocol, and then generates an IPv6 address based on the prefix .
After the new access point assigns an IP address for the mobile node, the mobile node performs mobile IP re-binding and re- association process with the mobile agent of the access point.
After that, the mobile node sets up a data service with access point C.
Example 3: it is supposed the SSID stored by the mobile node is VoTP@ ( 192.166.1.0 : 24 ) . cnc, 5 and the SSID configuration of access point D is VoTP6 (192.168.1.0:24) . un icom . As shown in Figure 5 :
The mobile node sends a Probe Request message to all the RF channels to perform a scan process when it needs handoff. During the scan process, the mobile node discovers access point D. The mobile node obtains the SSID information "VoTPCd ( '192. '1 b8. '1.0:24) . uni com" corresponding to access point D from the Probe Response message issued in reply by said access point D, and puts it into the candidate access point list. After comparing with its own stored SSID information, the mobile node selects access point D as the new access point, triggering the global handoff process.
Firstly, the mobile node performs an authentication process and Re-association process with access point D: The mobile node sends an Auth. Request (authentication request) message to access point D, and access point D responds with an Auth .Response (authentication response) message to the mobile node after receiving said request message. The mobile node sends a Re-association Request message to access point D, and access point D responds with a Re-association Response message to the mobile node after receiving said request message.
Once the authentication is passed and re-association with access point D is built, the access point router re-assigns an IP address for the mobile node by either a stateful DHCPv4/6 address assignment process or stateless address assignment process of neighbor discovery protocol. The process of DHCPv4/6 comprises: the terminal sending a message discovered by a DHCP service, and the DHCP server responding to the discovered message. Then the terminal sends an address request message, and the server assigns an IP address for the terminal based on its own condition and returns confirmation. After the accomplishment of the assignment, the terminal and the server maintain the address assignment state with their respective timers, and refresh the process to guarantee the validity of the assignment if overtime occurs. As both sides need to maintain the state machine, this type of assignment is stateful. The stateless address assignment only exists in IPv6, a process in which the terminal finds out the prefix of the subnet the port is located in through neighbor discovery protocol, and then generates an IPv6 address based on the prefix .
After the new access point assigns an IP address for the mobile node, the mobile node performs mobile IP re-binding and re- association process with the mobile agent of the access point.
After that, the mobile node sets up a data service with access point D. Reference is now made to Figure 6 showing the theoretical block diagram of an example according to the mobile node of the present invention:
The mobile node comprises an access point information storage module SOl for storing a candidate access point list information containing service set identifier information and signal strength information, an access point selection module S02 for determining handoff mode and a new access point based on the access point list information when the mobile node needs handoff, and a handoff performing module S03 for performing handoff to the new access point based on the determined handoff mode .
As mentioned in the description of the examples according to the method of present invention, in order to allow the mobile node to determine the handoff mode needs to be performed based on the service set identifier (SSID) information of access points, in the present invention, SSID is defined as the value of IP subnet, i.e. SSID is expressed using IP subnet value. In consideration that the subnet address may be repeatedly used in IPv4 network, for example, when a private IP address is used in the IP subnet, it is possible for adjacent access points with the same subnet value to belong to different subnets. Thus, in an IPv4 network, it is not sufficient to detect macro handoff by simply using IP subnet value. In view of the above, the present invention further sets the SSID structure as SIDQlPID . VID, wherein SID is service identifier string representing "audio", "video", etc, IPID is an IP subnet identifier string, and VID is a service provider identifier string such as "cnc", "Unicom", etc. Based on the SSID information with this type of structure, the mobile node can make optimal selection among a number of selected links.
IPID is a 40 bit integer for the IPv4 subnet, wherein the first 32 bits represent the IPv4 address and the later 8 bits represent the subnet mask length, whereas IPID is a 136 bit integer for the IPv6 subnet, wherein the first 128 bits represent the IPv6 address and the later 8 bits represent the prefix length.
The SSID information of the access point may be configured according to the above structure.
In order to obtain candidate access point information, in the present example, it is through the access point information acquiring module S04 to obtain candidate access point information including the information of SSID, signal strength, etc. corresponding to the access point. The SSID information can be obtained through messages such as a Beacon message or a Probe Response message in mobile IP, and be sent to access point information storage module SOl to set up the relation between access point and its corresponding service set identifier and signal strength.
The access point selection module S02 determines the preferred access point to perform the corresponding handoff operation based on the information stored in the access point storage module, such as service set identifier information or signal strength, or collective consideration of both service set identifier and signal strength.
In order to allow the access point selection module S02 to be able to preferably select access point needed to perform handoff, the mobile node of the present invention further comprises: a service set identifier storage module S05 for storing the service set identifier information of the mobile node, and a comparison module S06 respectively connected with the access point information storage module SOl and the service set identifier storage module S05 for comparing the service set identifier information in the access point list with the service set identifier information of the mobile node and informing the comparison result to the access point selection module S02. The access point selection module S02 determines the new access point based on the comparison result. The selection of a new access point and the particular handoff process of the mobile node of the present invention are similar to those in the description of the method of the present invention, and will not be described with unnecessary details.
Although the present invention is illustrated by way of examples, it will be appreciated for those skilled in the art that the present invention may have many modifications and variations without departing from the scope of the present invention which are expected to be included in the claims.

Claims

What is claimed is:
1. A method for increasing handoff speed of a mobile node in wireless LAN, which method comprises: determining the handoff mode and a new access point when the mobile node needs handoff; and performing handoff to the new access point based on the determined handoff mode.
2. The method as claimed in claim 1, wherein the step of determining the handoff mode and a new access point comprises: the mobile node acquiring a candidate access point list containing service set identifier information and signal strength information; and determining the handoff mode and the new access point based on the service set identifier information in the access point list.
3. The method as claimed in claim 2, wherein the step of the mobile node acquiring a candidate access point list comprises: the mobile node sending a probe request message to all the RF channels; and creating the access point list based on the received probe response message of the RF channels.
4. The method as claimed in claim 2, which method further comprises : setting the service set identifier structure as SIDijIPID. VID, wherein SID is service identifier string, IPID is IP subnet identifier string, and VID is service provider identifier string.
5. The method as claimed in claim 4, wherein,
IPID is a 40 bit integer for the IPv4 subnet, wherein the first 32 bits represent the IPv4 address and the later 8 bits represent the subnet mask length; and IPID is a 136 bit integer for the IPv6 subnet, wherein the first 128 bits represent the IPv6 address and the later 8 bits represent the prefix length.
6. The method as claimed in claim 4, wherein the step of determining the handoff mode and the new access point based on the service set identifier information in the access point list comprises : determining the position of each access point relative to the mobile node based on the service set identifier information; preferably selecting an access point in the same subnet as the mobile node to perform micro handoff; selecting the access point in the same area as the mobile node to perform macro handoff if there is no access point in the access point list located in the same subnet as the mobile node; and selecting the access point with the strongest signal based on the signal strength to perform global handoff if there is no access point in the access point list located in the same area as the mobile node.
7. The method as claimed in claim 6, wherein the step of determining the position of each access point relative to the mobile node based on the service set identifier information comprises : if all the SID, IPID and VID fields of the service set identifier in the access point list are identical to the SID, IPID and VID fields of the service set identifier stored by the mobile node, the access point of said service set identifier in the access point list is in the same subnet as the mobile node; if the SID and IPID fields of the service set identifier in the access point list are different from the SID and IPID fields of the service set identifier stored by the mobile node, and the VID fields are identical, the access point of said service set identifier in the access point list is in the same area as the mobile node.
8. A mobile node, which mobile node comprises: an access point information storage module for storing candidate access point list information containing service set identifier information and signal strength information; an access point selection module connected with the access point list storage module for determining the handoff mode and a new access point based on the access point list information when the mobile node needs handoff; and a handoff performing module connected with the handoff mode and access point selection module for performing handoff to the new access point based on the determined handoff mode.
9. The mobile node as claimed in claim 8, which mobile node further comprises: an access point information acquiring module connected with the access point information storage module for acquiring the information corresponding to each access point based on the response message of the access point received by the mobile node .
10. The mobile node as claimed in claim 8 or 9, which mobile node further comprises: a service set identifier storage module for storing the service set identifier information of the mobile node; and a comparison module respectively connected with the access point information storage module and the service set identifier storage module for comparing the service set identifier information in the access point list with the service set identifier information of the mobile node and informing the comparison result to the access point selection module.
PCT/EP2007/055202 2006-05-30 2007-05-29 Method for increasing handoff speed of mobile node in wireless lan and the mobile node WO2007138056A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP07729623A EP2022212A1 (en) 2006-05-30 2007-05-29 Method for increasing handoff speed of mobile node in wireless lan and the mobile node

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CNA2006100832041A CN101083610A (en) 2006-05-30 2006-05-30 Method for improving switch speed of mobile node in wireless LAN and mobile node
CN200610083204.1 2006-05-30

Publications (1)

Publication Number Publication Date
WO2007138056A1 true WO2007138056A1 (en) 2007-12-06

Family

ID=38434868

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2007/055202 WO2007138056A1 (en) 2006-05-30 2007-05-29 Method for increasing handoff speed of mobile node in wireless lan and the mobile node

Country Status (4)

Country Link
EP (1) EP2022212A1 (en)
KR (1) KR20090018671A (en)
CN (1) CN101083610A (en)
WO (1) WO2007138056A1 (en)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101945144A (en) * 2010-09-14 2011-01-12 中兴通讯股份有限公司 IP address redistribution method and service node
KR101033929B1 (en) * 2008-06-18 2011-05-11 삼성전자주식회사 Apparatus and method for supporting handover in mobile communication terminal without gps
WO2014085525A3 (en) * 2012-11-27 2014-09-25 Qualcomm Incorporated Fast association and address continuity for handoff between unmanaged access points
US8867488B2 (en) 2009-09-22 2014-10-21 Huawei Device Co., Ltd. Method, system and device for network handover
CN104125355A (en) * 2013-04-29 2014-10-29 深圳富泰宏精密工业有限公司 IP telephone conversation control method and system
EP3113544A1 (en) * 2012-12-29 2017-01-04 Intel Corporation Methods and arrangements for advertising services in wireless networks
WO2017101070A1 (en) * 2015-12-17 2017-06-22 Intel Corporation Fast moving scenario access point switching
CN107241718A (en) * 2017-06-13 2017-10-10 上海斐讯数据通信技术有限公司 A kind of discarding method and system of main secret key in pairs
TWI624186B (en) * 2014-04-03 2018-05-11 高通公司 Fast association and address continuity for handoff between unmanaged access points
CN111079140A (en) * 2018-10-18 2020-04-28 中国人寿保险股份有限公司 Method, device and system for preventing cheating

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5705415B2 (en) 2009-04-06 2015-04-22 ソニー株式会社 Wireless communication apparatus, communication system, communication method, and program
CN102625396B (en) * 2011-01-27 2017-09-12 中兴通讯股份有限公司 A kind of method for managing resource and system
CN102752271A (en) * 2011-04-22 2012-10-24 金锰 Information processing method based on radio-frequency signal strength
CN102625468A (en) * 2011-10-18 2012-08-01 北京小米科技有限责任公司 Access method to mobile internet
CN102843302B (en) * 2012-09-17 2015-02-25 福建星网锐捷网络有限公司 Terminal access method and device
CN105611587A (en) * 2015-09-22 2016-05-25 镇江锐捷信息科技有限公司 Wireless network seamless switching method using virtual IP
CN105744577B (en) * 2016-01-28 2019-01-18 武汉大学 A kind of mobile roaming switching method suitable for multi-hop underwater sound local area network
CN105992209A (en) * 2016-04-21 2016-10-05 深圳市蜂联科技有限公司 Method for communication through beacon frame embedded data under unrelated WIFI environment
CN109921898A (en) * 2019-03-28 2019-06-21 新华三技术有限公司 IPv6 stateless address generation method and device

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040253954A1 (en) * 2003-02-05 2004-12-16 Samsung Electronics Co., Ltd. Handover method in WLAN and mobile node device performing handover in WLAN
US20060052106A1 (en) * 2004-09-03 2006-03-09 Samsung Electronics Co., Ltd. Method and apparatus for performing fast handover

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040253954A1 (en) * 2003-02-05 2004-12-16 Samsung Electronics Co., Ltd. Handover method in WLAN and mobile node device performing handover in WLAN
US20060052106A1 (en) * 2004-09-03 2006-03-09 Samsung Electronics Co., Ltd. Method and apparatus for performing fast handover

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
JORDAN N ET AL: "Link-layer support for fast mobile IPv6 handover in wireless LAN based networks", LOCAL AND METROPOLITAN AREA NETWORKS, 2004. LANMAN 2004. THE 13TH IEEE WORKSHOP ON MILL VALLEY, CA, USA 25-28 APRIL 2004, PISCATAWAY, NJ, USA,IEEE, 25 April 2004 (2004-04-25), pages 139 - 143, XP010727813, ISBN: 0-7803-8551-9 *
LI L ET AL: "A X-CAST-BASED SEAMLESS HANDOVER SCHEME OVER WIRELESS LAN", IEICE TRANSACTIONS ON COMMUNICATIONS, COMMUNICATIONS SOCIETY, TOKYO, JP, vol. E88-B, no. 3, March 2005 (2005-03-01), pages 965 - 972, XP001225573, ISSN: 0916-8516 *

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101033929B1 (en) * 2008-06-18 2011-05-11 삼성전자주식회사 Apparatus and method for supporting handover in mobile communication terminal without gps
US8867488B2 (en) 2009-09-22 2014-10-21 Huawei Device Co., Ltd. Method, system and device for network handover
CN101945144A (en) * 2010-09-14 2011-01-12 中兴通讯股份有限公司 IP address redistribution method and service node
WO2014085525A3 (en) * 2012-11-27 2014-09-25 Qualcomm Incorporated Fast association and address continuity for handoff between unmanaged access points
US10051521B2 (en) 2012-11-27 2018-08-14 Qualcomm Incorporated Fast association and address continuity for handoff between unmanaged access points
US9924394B2 (en) 2012-12-29 2018-03-20 Intel Corporation Methods and arrangements for advertising services in wireless networks
EP3113544A1 (en) * 2012-12-29 2017-01-04 Intel Corporation Methods and arrangements for advertising services in wireless networks
CN104125355A (en) * 2013-04-29 2014-10-29 深圳富泰宏精密工业有限公司 IP telephone conversation control method and system
TWI624186B (en) * 2014-04-03 2018-05-11 高通公司 Fast association and address continuity for handoff between unmanaged access points
WO2017101070A1 (en) * 2015-12-17 2017-06-22 Intel Corporation Fast moving scenario access point switching
US10681606B2 (en) 2015-12-17 2020-06-09 Intel Corporation Fast moving scenario access point switching
CN107241718A (en) * 2017-06-13 2017-10-10 上海斐讯数据通信技术有限公司 A kind of discarding method and system of main secret key in pairs
CN111079140A (en) * 2018-10-18 2020-04-28 中国人寿保险股份有限公司 Method, device and system for preventing cheating
CN111079140B (en) * 2018-10-18 2023-06-27 中国人寿保险股份有限公司 Method, device and system for preventing cheating

Also Published As

Publication number Publication date
EP2022212A1 (en) 2009-02-11
CN101083610A (en) 2007-12-05
KR20090018671A (en) 2009-02-20

Similar Documents

Publication Publication Date Title
EP2022212A1 (en) Method for increasing handoff speed of mobile node in wireless lan and the mobile node
US7573846B2 (en) Method and system for supporting mobility of mobile terminal
CN101605077B (en) Method and device for supplying mobile access by wireless fidelity (WiFi) network
JP4934593B2 (en) Interworking method and interworking system between cellular network and wireless local area network
US7260075B2 (en) Fast duplicate address detection entity for managing information for fast duplicate address detection in distribution system and fast duplicate address detection method using the same
EP1869912B1 (en) Dynamically obtaining neighborhood information
EP2026621A2 (en) Method and apparatus for providing neighborhood AP information in a wireless LAN system
US8244253B2 (en) Method and apparatus for supporting fast mobility IP with link identifier prefix in wireless communication system
KR101375540B1 (en) Method and Apparatus for performing neighbor discovery in a heterogeneous network
KR20060045949A (en) Method for ip connectivity establishment procedures
US8059599B1 (en) Gateway assignment function
WO2005074307A1 (en) Method for dynamic address allocation using mobile ip in wireless portable internet system
KR20050065123A (en) Method for establishing channel between user agent and wireless access point in public wireless local area network
US20060291426A1 (en) Method and apparatus for performing fast handover in wireless network
US20150163656A1 (en) Wireless local area network system based on an access point (ap) supporting wireless terminal roaming
JP4496733B2 (en) Mobile communication system and handover method used therefor
US7649888B2 (en) System for link independent multi-homing in heterogeneous access networks
Vatn et al. The effect of using co-located care-of addresses on macro handover latency
EP2060134A1 (en) Dynamic temporary mac address generation in wireless networks
US6904281B2 (en) Method for discriminating network domain and interworking with the same in IMT-2000 system
CN101208910B (en) Apparatus and method for performing fast handover
CN111586676A (en) Method for realizing seamless roaming between routers
KR20050039302A (en) System for providing wireless local area network access environment based on access point and operating method of wireless internet protocol terminal

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 07729623

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2007729623

Country of ref document: EP

WWE Wipo information: entry into national phase

Ref document number: 9573/DELNP/2008

Country of ref document: IN

NENP Non-entry into the national phase

Ref country code: DE

WWE Wipo information: entry into national phase

Ref document number: 1020087031777

Country of ref document: KR