WIRELESS COMMUNICATIONS SYSTEM FOR CONTROLLING COMMUNICATION PATH

Abstract

A controller manages a connection of a wireless terminal to a wireless base station, and provides a source base station with information for connecting the wireless terminal by way of an anchor when the wireless terminal moves between wireless base stations. When devices on both sides of an anchor connected communication are wireless terminals connected to wireless base stations in said same wireless communications system, a wireless base station device switches a path such that data is transmitted/received between the wireless base stations to which the wireless terminals are connected on both sides of the anchor connected communication without intervention of the anchor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating the configuration of a conventional wireless communications system;

FIG. 2 is a block diagram illustrating the configuration of another conventional wireless communications system;

FIG. 3 is a block diagram illustrating the configuration of a yet another conventional wireless communications system;

FIG. 4 is a block diagram illustrating the configuration of a wireless communications system according to a first embodiment;

FIG. 5 is a diagram illustrating a protocol stack of each device in a wireless communications system which performs an optimization with an IP tunnel;

FIG. 6 is a block diagram illustrating the configuration of CTRL and AP in the first embodiment;

FIG. 7 is a conceptual diagram for describing exemplary operations up to an anchor connection in the first embodiment;

FIG. 8 is a diagram for describing a specific example of a path optimization according to the first embodiment;

FIG. 9 is a diagram for describing the operation of the specific example illustrated in FIG. 8;

FIG. 10 is a diagram illustrating a protocol stack of each device in the specific example illustrated in FIG. 8, and how the address of a packet is converted when it is transferred between devices in IP tunnel processing;

FIG. 11 is a sequence diagram illustrating operations for the path optimization in the specific example illustrated in FIG. 8;

FIG. 12 is a diagram for describing operations for the path optimization in a second embodiment;

FIG. 13 is a block diagram illustrating the configuration of CTRL and AP in the second embodiment;

FIG. 14 is a diagram for describing a specific example of the path optimization according to the second embodiment;

FIG. 15 is a diagram for describing the operation of the specific example illustrated in FIG. 14;

FIG. 16 is a sequence diagram illustrating operations for the path optimization in the specific example illustrated in FIG. 15;

FIG. 17 is a diagram for describing another operation of the specific example illustrated in FIG. 14;

FIG. 18 is a diagram for describing a yet another operation of the specific example illustrated in FIG. 14;

FIG. 19 is a diagram for describing the operation of another specific example;

FIG. 20 is a diagram for describing operations for determining whether or not the path optimization is applicable in a third embodiment;

FIG. 21 is a diagram for describing operations for the path optimization in the third embodiment;

FIG. 22 is a block diagram illustrating the configuration of CTRL and AP in the third embodiment; and

FIG. 23 is a sequence diagram illustrating operations for the path optimization.

Claims

1-24. (canceled)

25. A wireless communications system having a plurality of wireless base stations located such that a mobile wireless terminal can be connected thereto, wherein said wireless terminal is allowed to continue a communication when said wireless terminal moves between wireless base stations by transmitting/receiving data between a source base station which assumes a position of an anchor and a destination base station, said system comprising: a controller for managing a connection of said wireless terminal to a wireless base station, and providing a source base station with information for connecting said wireless terminal by way of the anchor when said wireless terminal moves between wireless base stations; anda plurality of wireless base station devices each for switching a path such that dada is transmitted/received between wireless base stations to which wireless terminals are connected on both sides of an anchor connected communication without intervention of the anchor.

26. The wireless communications system according to claim 25, wherein said wireless base station switches a path such that data is transmitted/received between wireless base stations to which wireless terminals are connected on both sides without intervention of the anchor when devices on both sides of the anchor connected communication are wireless terminals connected to wireless base stations in said same wireless communications system.

27. The wireless communications system according to claim 26, wherein: said wireless base station device requests said controller for a path optimization when said wireless base station device per se assumes a position of a source base station to make an anchor connection in response to a movement of a wireless terminal, andsaid controller determines that the path optimization is applicable when a counterpart of said wireless terminal connected by way of the anchor by said wireless base station which requests for the path optimization is a wireless terminal connected to a wireless base station in said same wireless communications system, and instructs a wireless base station device of a destination base station and a wireless base station device of a counterpart base station to switch a path.

28. The wireless communications system according to claim 26, wherein: said wireless base station device determines that the path optimization can applied when said wireless base station device per se assumes a position of a source base station to make an anchor connection in response to a movement of a wireless terminal, if a counterpart of said mobile wireless terminal is a wireless terminal connected to a wireless base station in said same wireless communications system, and instructs said controller to optimize the path, andsaid controller instructs a wireless base station device of a destination base station and a wireless base station device of a counterpart base station to switch the path upon receipt of a path optimization instruction from said wireless base station device of said source base station.

29. The wireless communications system according to claim 26, wherein said wireless base station device determines that the path optimization can applied when, said wireless base station device per se assumes a position of a source base station to make an anchor connection in response to a movement of a wireless terminal, if the counterpart of said mobile wireless terminal is a wireless terminal connected to a wireless base station in said same wireless communications system, and instructs a wireless base station device of a destination base station and a wireless base station device of a counterpart base station to switch the path.

30. The wireless communications system according to claim 28, wherein: said wireless base station devices notify a list of wireless terminals connected thereto to mutually share the list within the same LAN, and each said wireless base station device determines whether or not the counterpart of said mobile wireless terminal is a wireless terminal connected to a wireless base station in said same wireless communications system by querying any wireless base station device within a LAN in which the counterpart exists, when said wireless base station device per se assumes a position of a source base station to make an anchor connection in response to a movement of said wireless terminal.

31. The wireless communications system according to claim 29, wherein: said wireless base station devices notify a list of wireless terminals connected thereto to mutually share the list within the same LAN, and each said wireless base station device determines whether or not the counterpart of said mobile wireless terminal is a wireless terminal connected to a wireless base station in said same wireless communications system by querying any wireless base station device within a LAN in which the counterpart exists, when said wireless base station device per se assumes a position of a source base station to make an anchor connection in response to a movement of said wireless terminal.

32. The wireless communications system according to claim 28, wherein: said wireless base station device decrements TTL by one in a packet when said packet is transferred to a wireless terminal connected to said wireless base station device itself over a wireless channel, andwhen said wireless base station device per se assumes a position of a source, base station to make an anchor connection in response to a movement of a wireless terminal which has been connected to said wireless base station device to communicate with a counterpart within the same LAN, said wireless base station device determines whether or not said counterpart is a wireless terminal connected to a wireless base station in said same wireless communications system based on a response to an 1CMP ECHO request sent to said counterpart with TTL being set equal to “1.”

33. The wireless communications system according to claim 29, wherein: said wireless base station device decrements TTL by one in a packet when said packet is transferred to a wireless terminal connected to said wireless base station device itself over a wireless channel, andwhen said wireless base station device per se assumes a position of a source base station to make an anchor connection in response to a movement of a wireless terminal which has been connected to said wireless base station device to communicate with a counterpart within the same LAN, said wireless base station device determines whether or not said counterpart is a wireless terminal connected to a winless base station in said same wireless communications system based on a response to an ICMP ECHO request sent to said counterpart with TTL being set equal to “1.”

34. The wireless communications system according to claim 25, wherein said wireless base station device encapsulates a packet between said mobile wireless terminal and a counterpart wireless terminal thereof to directly transmit/receive the encapsulated packet between said source base station and said counterpart base station.

35. The wireless communications system according to claim 34, wherein said wireless base station device converts a MAC address of a packet between said mobile wireless terminal and a counterpart wireless terminal thereof to a value indicative of a respective counterpart wireless terminal, and thereafter encapsulates a packet to directly transmit the encapsulated packet to a respective counterpart wireless base station.

36. The wireless communications system according to claim 25, wherein said wireless base station device holds a list of past determination results in regard to applicability of the path optimization, and determines that the path optimization is not applicable to a path which is designated as the path optimization not applicable in the list without again making the determination,

37. A wireless base station device installed in plural such that a mobile wireless terminal can be connected thereto, wherein said wireless base station device allows said wireless terminal to continue a communication by transmitting/receiving data between a source which assumes a position of an anchor and a destination when said wireless terminal moves, said device comprising: a determination module for determining whether or not an optimization is applicable to a path between wireless terminals on both sides of an anchor connected communication; anda path switching module for switching the path such that data is transmitted/received between wireless base stations to which said wireless terminals on both sides are connected without intervention of the anchor, when the path optimization is determined to be applicable.

38. The wireless base station device according to claim 37, wherein said determination module determines that the path optimization is applicable when devices on both sides of the anchor connected communication are wireless terminals connected to wireless base stations in said same wireless communications system.

39. The wireless base station device according to claim 38, wherein: said determination module determines that the path optimization is applicable if a counterpart of said mobile wireless terminal is a wireless terminal connected to a wireless base station in said same wireless communications system, when said wireless base station device per se assumes a position of a source base station to make an anchor connection in response to a movement of said wireless terminal, and instructs a wireless base station device of a destination base station and a wireless base station device of a counterpart base station to switch a path, andsaid path switching module switches the path in response to an instruction from the source base station when said wireless base station device assumes a position of a destination base station or a counterpart base station.

40. The wireless base station device according to claim 39, wherein said determination module notifies a list of wireless terminals connected thereto to mutually share the list within the same LAN, and determines whether or not the counterpart of said mobile wireless terminal is a wireless terminal connected to a wireless base station in said same wireless communications system by querying any wireless base station device within a LAN in which the counterpart exists, when said wireless base station device per se assumes a position of a source base station to make an anchor connection in response to a movement of said wireless terminal,

41. The wireless base station device according to claim 39, further comprising a processing module for decrementing TTL by one in a packet when the packet is transferred to a wireless terminal connected to said wireless base station device over a wireless channel, wherein: when said wireless base station device per se assumes a position of a source base station to make an anchor connection in response to a movement of a wireless terminal which has been connected to said wireless base station device to communicate with a counterpart within the same LAN, said determination module determines whether or not said counterpart is a wireless terminal connected to a wireless base station in said same wireless communications system based on a response to an ICMP ECHO request sent to said counterpart with TTL being set equal to “1.”

42. The wireless base station device according to claim 37, wherein said path switching module encapsulates a packet between said mobile wireless terminal and a counterpart wireless terminal thereof to directly transmit/receive the encapsulated packet directly between said source base station and said counterpart base station.

43. The wireless base station device according to claim 42, further comprising a destination MAC conversion module for converting a MAC address of a packet between said mobile wireless terminal and said counterpart wireless terminal to a value indicative of said counterpart wireless terminal, and providing the packet to said path switching module, wherein said path switching module encapsulates the packet provided thereto from said destination MAC conversion module to directly transmit the encapsulated packet to a counterpart wireless base station device.

44. The wireless base station device according to claim 37, wherein said wireless base station device holds a list of past determination results in regard to applicability of the path optimization, and determines that the path optimization is not applicable to a path which is designated as the path optimization not applicable in the list without again making the determination.

45. In a wireless communications system having a plurality of wireless base stations located such that a mobile wireless terminal can be connected thereto, wherein said wireless terminal is allowed to continue a communication when said wireless terminal moves between wireless base stations by transmitting/receiving data between a source base station which assumes a position of an anchor and a destination base station, a wireless communication controller for managing a plurality of said wireless base stations, comprising: a determination module for receiving a request for a path optimization from a wireless base station which assumes a position of a source base station to make an anchor connection in response to a movement of a wireless terminal, and determining whether or not the path optimization is applicable to a path between said mobile wireless terminal and a counterpart wireless terminal thereof; anda tunnel setting module for instructing a destination wireless base station of said wireless terminal and a wireless base station of said counterpart wireless terminal to switch the path to transmit/receive data without intervention of the anchor when said determination module determines that the path optimization is applicable.

46. The wireless communication controller according to claim 45, wherein said determination module determines that the path optimization is applicable when the counterpart of said mobile wireless terminal is a wireless terminal connected to a wireless base station in said same wireless communications system.

47. In a wireless communications system having a plurality of wireless base stations located such that a mobile wireless terminal can be connected thereto, wherein said wireless terminal is allowed to continue a communication when said wireless terminal moves between wireless base stations by transmitting/receiving data between a source base station which assumes a position of an anchor and a destination base station, a computer program product for causing a computer to manage a plurality of said wireless terminals, comprising: a procedure for receiving a request for a path optimization from a wireless base station which assumes a position of a source base station to make an anchor connection in response to a movement of a wireless terminal, and determining whether or not the path optimization is applicable to a path between said mobile wireless terminal and a counterpart wireless terminal thereof; and a procedure for instructing a destination wireless base station of said wireless terminal and a wireless base station of said counterpart wireless terminal to switch the path to transmit/receive data without intervention of the anchor when said determination module determines that the path optimization is applicable.

48. The program product according to claim 47, wherein the path optimization is determined to be applicable when the counterpart of said mobile wireless terminal is a wireless terminal connected to a wireless base station in said same wireless communications system.

49. A path control method in a wireless communications system having a plurality of wireless base stations installed such that a mobile wireless terminal can be connected thereto, wherein said wireless terminal is allowed to continue a communication when said wireless terminal moves between wireless base stations by transmitting/receiving data between a source base station which assumes a position of an anchor and a destination base station, said method comprising: determining whether or not a path optimization is applicable to a path between wireless terminals on both sides of an anchor connected communication; andswitching the path such that data is transmitted/received between wireless base stations to which said wireless terminals on both sides are connected, without intervention of the anchor when determining that the path optimization is applicable.

50. The path control method according to claim 49, further comprising determining that the path optimization is applicable when devices on both sides of the anchor connected communication are wireless terminals connected to wireless base stations in said same wireless communications system.