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Telecommunications

Patent Issued for Apparatus for Controlling Handover between Heterogeneous Networks, Method of Performing Handover between Heterogeneous Networks, and Mobile Router

2012 AUG 1 (VerticalNews) -- By a News Reporter-Staff News Editor at Telecommunications Weekly -- According to news reporting originating from Alexandria, Virginia, by VerticalNews journalists, a patent by the inventors Hong, Hyun-ha (Seoul, KR); Han, Ki-seop (Seoul, KR); Chang, Dae-ig (Daejeon-si, KR); Lee, Ho-jin (Daejeon-si, KR), filed on September 3, 2009, was cleared and issued on July 24, 2012.

The assignee for this patent, patent number 8223719, is Electronics and Telecommunications Research Institute (Daejeon-si, KR).

Reporters obtained the following quote from the background information supplied by the inventors: "The following description relates to inter-network handover, and more particularly, to an apparatus for controlling handover between heterogeneous networks, a method of performing handover between heterogeneous networks in a mobile router, and a mobile router.

"A mobile network in a vehicle such as a high-speed train having a mobile router and a fixed node uses mobile network technology based on Internet protocol version 4 (IPv4). When handover occurs between domains in the mobile network, packets transmitted from a correspondent node during visited network movement detection, agent detection, and a registration process are lost. Thus, a high-speed handover procedure is required.

"For this reason, a technique of applying fast mobile IPv6 to mobile nodes while a high-speed mobile router moving at speeds in excess of 300 km/h like a high-speed train is performing handover has been suggested. The mobile router moves from an access router before handover, receives prefix information corresponding to a new access router, and then transmits the information to a mobile node. The mobile router and the mobile node request the previous access router for fast IPv6 binding update.

"The previous access router and the new access router exchange handover initiate and notification messages according to fast IPv6 binding, and the previous access router transmits a fast binding acknowledgement message to the mobile node. Then, data sent to the mobile router and the mobile node using a previous prefix is transmitted from the previous access router via the new access router through a tunnel. When the mobile router receives the fast binding acknowledgement message, it immediately transmits a zero lifetime message for releasing the previous prefix to the mobile node, and then the mobile node transmits the data using the new prefix.

"Fast mobile IPv6 used for handover as described above prevents packet loss during communication between a mobile node and a correspondent node while a mobile router is performing handover, and also reduces handover delay. However, a vehicle such as a high-speed train has small mobile cells, and thus probability of handover failure increases when the vehicle passes through several cells at high speed. Also, minimum time required for handover between cells is not ensured, and thus packets are lost.

"Meanwhile, there is another technique for applying handover between satellite and wireless networks to a high-speed mobile router using a link trigger signal of multiple interfaces. According to this technique, a mobile router having multiple interfaces controls handover between mobile networks using sequential link up/down trigger signals. This technique prevents packet loss and session interruption regardless of movement speed of the mobile router, and when handover is performed between a terrestrial wireless home network and a visited satellite network, reduces power consumption by placing an inactivated network access interface in a sleep state. However, when the high-speed train that is providing service in a visible region of the satellite network enters a shadow region of the satellite network, handover to an interoperable wireless network should be immediately performed to continue the service. In this case, the mobile router passes through cells of the wireless network at high speed, and thus it is difficult to detect mobility using a link trigger signal. In other words, handover to the corresponding wireless network may fail, or time taken to perform handover may increase."

In addition to obtaining background information on this patent, VerticalNews editors also obtained the inventors' summary information for this patent: "The following description relates to a handover method and handover control apparatus capable of reducing network mobility detection time and providing Internet service in which a session connected to a fixed node is not interrupted.

"Also, the following description relates to a handover method and handover control apparatus that automatically generate and manage satellite/wireless network area information, which becomes a reference for handover control determination at an administrator's request, according to a change in the wireless environment of satellite and terrestrial networks, and thus can actively adapt to the change in network environment.

"According to an exemplary aspect, there is provided a method of performing handover between heterogeneous networks in a mobile router managing a mobile network, including: determining whether a handover to a network employing a different method from a network to which the mobile router belongs is required based on information prestored in the mobile router, the network to which the mobile router belongs determined by current location information of the mobile router; and performing the handover according to the result of the determination.

"The method may further include obtaining information about the network to which the handover will be performed from link trigger signal information corresponding to the current location information of the mobile router, based on the prestored information.

"The method may further include, before the determining of whether the handover is required: monitoring link trigger signal information when the mobile router moves; determining whether the handover to the network employing the different method is required based on the link trigger signal information; performing the handover according to the result of the determination; and matching information about a location at which the handover is performed with the link trigger signal information and storing the result of the matching.

"According to another exemplary aspect, there is provided an apparatus for controlling handover between heterogeneous networks, including: a location information recognizer recognizing current location information of a mobile router managing a mobile network; a handover initiation information storage storing handover location information; a handover determiner determining whether a handover to a network employing a different method from a network accessed by the mobile router is required according to the current location information of the mobile router recognized by the location information recognizer, based on information prestored in the handover initiation information storage; and a handover performer performing the handover according to the result of the determination.

"The apparatus may further include an information collector matching link trigger signal information with the current location information of the mobile router when the handover determiner determines that the handover is required, and storing the result of the matching in the handover initiation information storage, wherein the information collector includes a link trigger information collector collecting the link trigger signal information; and a location information collector collecting the location information recognized by the location information recognizer.

"When the apparatus moves, the information collector may match location information of the apparatus with up/down link information of link trigger signals for networks employing different methods at the current location of the apparatus, and store the results of the matching in the form of a table.

"The handover determiner may recognize link trigger signal information according to the current location information of the apparatus, and recognizes information about the network to which the handover will be performed according to the link trigger signal information.

"According to still another exemplary aspect, there is provided a mobile router comprising an apparatus for controlling handover between heterogeneous networks, wherein the apparatus includes: a location information recognizer recognizing current location information of the mobile router; a handover initiation information storage storing handover location information; a handover determiner determining whether a handover to a network employing a different method is required according to the current location information recognized by the location information recognizer, based on information stored in the handover initiation information storage; and a handover performer performing the handover according to the result of the determination.

"The apparatus may further includes: an information collector matching link trigger signal information with the current location information of the mobile router when the handover determiner determines that the handover is required, and storing the result of the matching in the handover initiation information storage, wherein the information collector includes a link trigger information collector collecting the link trigger signal information and a location information collector collecting the location information recognized by the location information recognizer.

"Additional aspects 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.

"It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed."

For more information, see this patent: Hong, Hyun-ha; Han, Ki-seop; Chang, Dae-ig; Lee, Ho-jin. Apparatus for Controlling Handover between Heterogeneous Networks, Method of Performing Handover between Heterogeneous Networks, and Mobile Router. U.S. Patent Number 8223719, filed September 3, 2009, and issued July 24, 2012. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=43&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=2140&f=G&l=50&co1=AND&d=PTXT&s1=20120717.PD.&OS=ISD/20120717&RS=ISD/20120717

Keywords for this news article include: Mobile Network, Wireless Network, Wireless Technology, Network Technologies, Information Technology, Information and Data Storage, Electronics And Communications, Electronics and Telecommunications Research Institute.