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EP-4236568-B1 - OPTIMIZING RELAYED COMMUNICATION WHEN A SEGMENT IS DISCONNECTED

EP4236568B1EP 4236568 B1EP4236568 B1EP 4236568B1EP-4236568-B1

Inventors

  • TAKEDA, HIROKI
  • SHOU, Kou
  • MIYAKE, Yasutomo
  • WATANABE, SHINGO

Dates

Publication Date
20260506
Application Date
20190214

Claims (5)

  1. A first relay apparatus (103) in a wireless communication system including a base station apparatus (101), the first relay apparatus (103) and a second relay apparatus (102), wherein the first relay apparatus (103) and the second relay apparatus (102) perform, using a first communication method, relaying on a part of a communication link related to communication performed by the base station apparatus (101), and the second relay apparatus (102) performs relaying on a part of the communication link between the base station apparatus (101) and the first relay apparatus (103), and the first relay apparatus (103) is configured to transmit, to the base station apparatus (101) and using a second communication method different from the first communication method, information indicating that disconnection on a segment, forming the communication link, between the second relay apparatus (102) and the first relay apparatus (103) is detected, and to re-establish, using the first communication method, connection on the segment based on an instruction received from the base station apparatus (101) using the second communication method.
  2. The first relay apparatus according to claim 1, wherein the first communication method is a method compliant with a fifth generation cellular communication standard, and the second communication method is a method compliant with a Long Term Evolution, LTE, standard.
  3. The first relay apparatus according to claim 1, wherein the first relay apparatus (103) is configured to transmit, to the second relay apparatus (102), the information indicating disconnection on the segment.
  4. A communication method performed by a first relay apparatus (103) in a wireless communication system including a base station apparatus (101), the first relay apparatus (103) and a second relay apparatus (102) wherein the first relay apparatus (103) and the second relay apparatus perform (S502), using a first communication method, relaying on a part of a communication link related to communication performed by the base station apparatus (101), and the second relay apparatus (102) performs relaying on a part of the communication link between the base station apparatus (101) and the first relay apparatus (103), and the communication method comprises: transmitting (S504), to the base station apparatus (101) and using a second communication method different from the first communication method, information indicating that disconnection on a segment, forming the communication link, between the base second relay apparatus (102) and the first relay apparatus (103) is detected; and re-establishing (S508), using the first communication method, connection on the segment based on an instruction received (S507) from the base station apparatus (101) using the second communication method.
  5. A computer program for causing a computer comprised in the first relay apparatus (103) of claim 1 to execute the steps of the method of claim 4.

Description

TECHNICAL FIELD The present invention relates to a relay apparatus and a communication method performed by the same, and specifically relates to a control technique used during relay communication in a wireless communication network. BACKGROUND ART In the 3rd Generation Partnership Project (3GPP), a relay communication technique for enabling communication between a base station apparatus and a remote terminal has been discussed (see NPTL 1 and NPTL 2). In relay communication, one or more relay apparatuses are included on a communication path between a base station apparatus and a terminal. Also, the one or more relay apparatuses receive a signal transmitted from the base station apparatus and transfer the signal to the terminal apparatus, and receive a signal transmitted from the terminal apparatus and transfer the signal to the base station apparatus. CITATION LIST NON-PATENT LITERATURE NPTL 1: 3GPP TR 36.806, V9.0.0, March 2010NPTL 2: 3GPP TR 36.826, V11.0.0, September 2012 Further background art is provided in US 2007/195799 A1 and JP 4392789 B2. US 2007/195799 A1 discloses a packet routing method for reorganizing a path from a transmission source terminal to a destination terminal. A radio receiver part detects, from a decrease of the field intensity or the like, a cut-off of a communication with a communication device using a radio signal to directly transmit packets. A control part determines whether the local terminal device including it is the packet destination radio terminal device or the packet transmission source radio terminal device. When it is determined that the communication with a communication device using the radio signal to directly transmit packets is cut off and that the local terminal device is the transmission source radio terminal device, a radio transmitter part broadcasts a request signal of path restoration addressed to the packet destination communication device. JP 4392789 B2 discloses a method of re-establishing a path of an ad-hoc wireless network, for starting to establish another path while maintaining communication in an existing path if a defective link is detected on the existing path. To this end, a wireless terminal is provided which includes a means for monitoring a reception state of an adjacent link, a means for sending a path error message to an end terminal having a defective link with a reception state below a predetermined re-establishment threshold as part of its path, a means for substitutively responding a path response message to a path request message having a registered path to its destination, a means for inhibiting the substitutive response of the path response message when the registered path contains the defective link, and a means for discarding the path request message received from the defective link. SUMMARY OF INVENTION TECHNICAL PROBLEM In relay communication, several problems can occur accompanying establishment of a wireless link between the base station apparatus and the relay apparatus. SOLUTION TO PROBLEM The present invention provides a technique for solving at least one of the problems in relay communication. More particularly, the present invention provides a relay apparatus as defined in Claim 1 of the appended claims. Details of certain embodiments are set out in the dependent claims. Also provided is a communication method as defined in Claim 4, and a computer program as defined in Claim 5. ADVANTAGEOUS EFFECTS OF INVENTION According to the present invention, at least one of the problems in relay communication can be solved. Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings. Note that the same reference numerals denote the same or like components throughout the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain principles of the present claimed invention which is only illustrated, at least for method claim 4, by the figure 5. Fig. 1 is a diagram showing an example of a configuration of a wireless communication system accompanying relay transmission according to a first embodiment.Fig. 2 is a diagram showing an example of a hardware configuration of a control apparatus according to a first embodiment.Fig. 3 is a diagram showing an example of a functional configuration of the control apparatus according to the first embodiment.Fig. 4 is a diagram showing an example of a functional configuration of a relay apparatus according to the first embodiment.Fig. 5 is a diagram showing an example of a flow of processing executed by the wireless communication system according to the first embodiment.Fig. 6 is a diagram showing an example of a configuration of a wireless communication system accompanying relay transmission according to a second embodiment.F