Radio relay apparatus, communication control method thereof, and communication system

The radio relay apparatus 1 stores MAC addresses of the radio terminals 2a and 2b and IP addresses assigned to the radio terminals 2a and 2b by the DHCP server 5 on the IP network 4 in the memory unit of the radio relay apparatus 1. The radio relay apparatus 1 monitors the information of MAC addresses and IP addresses of the source radio terminal and the destination radio terminal included in the packet routed through its own apparatus, and based on the address information stored in the memory unit, when it determines that the radio terminals 2a and 2b communicate each other via its own apparatus, transitions from the first communication mode over the IP network 4 to the second communication mode not over the IP network 4.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Japanese Patent Application No. 2011-213021 filed on Sep. 28, 2011, the entire contents of which are incorporated herein by reference.

FIELD

The present invention relates to a radio relay apparatus that relays radio communication between a terminal and a base station, a communication control method thereof, and a communication system.

BACKGROUND

When a radio terminal subordinate to WiMAX®-WiFi radio relay apparatus

(WiMAX-WiFi bridge) communicates with a radio terminal subordinate to the same radio relay apparatus, communication in a first communication mode by which communication is performed with WiMAX connection via IP network and communication in a second communication mode by which communication is performed through WiFi LAN connection are available, by disconnecting WiMAX connection and considering the radio relay apparatus as a WiFi access point. If radio terminals subordinate to the same radio relay apparatus exist and communicate each other at short range, they can communicate each other by switching between the two modes depending on the situation.

Furthermore, Patent Literature 1 discloses a method and an apparatus configured to seamlessly switch a mobile apparatus between WWAN including WiMAX and WLAN, such as WiFi.

CITATION LIST

SUMMARY OF INVENTION

However, the conventional communication system has no function by which the radio relay apparatus prompts the radio terminal to switch to the second communication mode. Thus, after such the radio terminals are connected each other in the first communication mode over IP network and start communication and the like, even if they are subordinate to a radio relay apparatus and thus are in an environment in which they could communicate each other in the second communication mode, they cannot switch smoothly from the first communication mode to the second communication mode.

The present invention has been conceived, in light of the above problem, and to provide a radio relay apparatus capable of smoothly switching from the first communication mode that is performed over IP network to the second communication mode that is performed not over IP network. a communication method thereof and a communication system.

In order to achieve the above-described object, the present invention is characterized in that it provides a radio relay apparatus in a communication system including a server on the Internet, a radio relay apparatus and a plurality of radio terminals, in which the radio relay apparatus includes a memory unit configured to store the information of MAC addresses of the radio terminals and IP addresses assigned to the radio terminals by the server and a control unit configured to monitor the information of MAC addresses and IP addresses of a source radio terminal and a destination radio terminal included in packets routed through the radio relay apparatus (the apparatus itself), the control unit controlling, if it determines, based on the information of MAC addresses and IP addresses stored in the memory unit, that the radio terminals communicate each other via its own apparatus, so that the communication between the radio terminals is transitioned from the communication in the first communication mode over the Internet to the communication in the second communication mode over a local area network, not over the Internet.

If the communication quality drops to below a predetermined level or at least either one of the radio terminals is handed over during communication in the second communication mode, the control unit may preferably return the communication between the radio terminals from the communication in the second communication mode to the communication in the first communication mode.

Values representing the communication quality may preferably be at least one of RSSI (received signal strength), SINR (signal-to-interference noise ratio) and FER (frame error rate).

Furthermore, the present invention is characterized in that it provides a communication control method of a radio relay apparatus in a communication system including a server on the Internet, a radio relay apparatus and a plurality of radio terminals, including the steps of storing the information of MAC addresses of the radio terminals and IP addresses assigned to the radio terminals by the server in the memory unit, monitoring the information of MAC addresses and IP addresses of a source radio terminal and a destination radio terminal included in packets routed through its own apparatus, and controlling, when it determines, based on the information of MAC addresses and IP addresses stored in the memory unit, that the radio terminals communicate each other via its own apparatus, so that the communication between the radio terminals is transitioned from the communication in the first communication mode over the Internet to the communication in the second communication mode over a local area network, not over the Internet.

The communication control method according to the present invention may preferably include a step of, when the communication quality drops to below a predetermined level or at least either one of the radio terminals is handed over during communication in the second communication mode, returning the communication between the radio terminals from the communication in the second communication mode to the communication in the first communication mode.

Values representing the communication quality may preferably be at least one of RSSI (received signal strength), SINR (signal-to-interference noise ratio) and FER (frame error rate).

Furthermore, the present invention is characterized in that it provides a communication system composed of a server on the Internet, a radio relay apparatus and a plurality of radio terminals, the communication system including a first communication mode in which a radio terminal communicates with another radio terminal subordinate to the radio relay apparatus over the radio relay apparatus and the Internet and a second communication mode in which the radio terminal communicates with the other radio terminal subordinate to the radio relay apparatus over the radio relay apparatus, and the radio relay apparatus transitioning, when it determines that the radio terminals communicate each other via its own apparatus, the communication between the radio terminals from the communication in the first communication mode to the communication in the second communication mode.

When the communication level drops to below the predetermined level or at least either one of the radio terminals is handed over during communication in the second communication mode, the radio relay apparatus may preferably return the communication between the radio terminals from the communication in the second communication mode to the communication in the first communication mode.

Values representing the communication quality may preferably be at least one of RSSI (received signal strength), SINR (signal-to-interference noise ratio) and FER (frame error rate).

In the present invention, the radio resource of the network can be assigned to other radio terminals by controlling so that the communication is switched from the first communication mode over the IP network to the second communication mode not over the IP network, thus the radio resource is not wasted. Moreover, in the present invention, charge to a radio terminal user required for a higher radio communication in the first communication mode can be reduced by switching to the second communication mode.

DESCRIPTION OF EMBODIMENT

The embodiment of the present invention will be described with reference to the drawings.FIG. 1is a diagram illustrating a configuration of a communication system in which a radio relay apparatus according to the present embodiment of the present invention is used. The radio relay apparatus1relays radio communication between the radio terminals2a,2band the base station3. The base station3is connected to the DHCP (Dynamic Host Configuration Protocol) server5and the service server6on the IP network4, such as the Internet. The DHCP server5assigns IP addresses to the radio terminals2a and2band manages them. The service server6provides a service to the user of the radio terminals2aand2b.

FIG. 2is a schematic configuration diagram of the radio relay apparatus according to the embodiment of the present invention illustrated inFIG. 1. As illustrated inFIG. 2, the radio relay apparatus1includes a terminal-side communication unit11, a base-station-side communication unit12, a memory unit and a control unit14. The terminal-side communication unit11communicates with the radio terminals2aand2bvia WiFi, and the base-station-side communication unit12communicates with the base station3via WiMAX.

The memory unit13stores MAC addresses of the radio terminals2aand2band IP addresses assigned to the radio terminals2aand2bby the DHCP server5on the IP network4.

The control unit14monitors the information of MAC addresses and IP addresses of the source radio terminal and the destination radio terminal included in the packets routed through its own apparatus, and when it determines, based on the address information stored in the memory unit13, that the communication between the radio terminals2aand2bis routed through its own apparatus, controls so that the communication between the radio terminals2aand2bis transitioned from the communication in the first communication mode in which communication is performed over the IP network4with WiMAX connection to the second communication mode in which communication is performed, not over the IP network4, but through LAN connection of WiFi, by disconnecting WiMAX connection and considering its own apparatus as a WiFi access point. Furthermore, the control unit14controls, when the communication quality drops to below a predetermined level or at least either one of the radio terminals is handed over during communication in the second communication mode, so that communication between the radio terminals2aand2bis returned from the communication in the second communication mode to the communication in the first communication mode.

Next, operation of the radio relay apparatus according to the embodiment of the present invention will be described.FIG. 3is a flowchart illustrating an operation of the radio relay apparatus. InFIG. 3, the case of a battle game where, the radio terminal subordinate to the radio relay apparatus is considered as a radio terminal for game having a radio function, and the radio terminal for game (hereinafter referred to as a terminal2a) communicates with the other radio terminal for game (hereinafter referred to as a terminal2b) present on the network, is taken for example to explain the operation of the radio relay apparatus. The terminals2aand2bhave a function of switching the communication mode to the second communication mode.

First, the terminal2asubordinate to the radio relay apparatus1obtains access to the service server6for game on the IP network4to play a battle game. At this time, the DHCP server5assigns an IP address to the terminal2a, and the radio relay apparatus1stores MAC address and IP address of the terminal2ain the memory unit13(S101).

Next, the terminal2bsubordinate to the radio relay apparatus1gains access to the service server6for game on the IP network4to play a battle game. At this time, the DHCP server5assigns an IP address to the terminal2b, and the radio relay apparatus1stores MAC address and IP address of the terminal2bin the memory unit13(S102).

Then, when the terminal2aissues a challenge to fight a battle to the terminal2b, the packet transmitted from the terminal2ais forwarded to the other router via the radio relay apparatus1, using the superordinate network, passes through hops and finally reaches the same radio relay apparatus1(S103).

The radio relay apparatus1monitors whether or not the Mac address (and the IP address) of the source terminal (terminal2a) and the Mac address (and the IP address) of the destination terminal (terminal2b) in the packet reaching its own apparatus match the Mac address (and the IP address) of the terminals2aand2bstored in the memory unit13(S104). If the addresses match, then the radio relay apparatus1recognizes that the terminal2aand the terminal2bexist subordinate to the apparatus itself.

If the addresses match and the radio relay apparatus1recognizes that the terminals2aand2bexist subordinate to its own apparatus, the radio relay apparatus1transmits the challenge issued by the terminal2ato the terminal2b, and transmits a message for encouraging switch to the communication in the second communication mode to the terminal2aas well (S105).

Subsequently, when the radio relay apparatus1receives, from the terminal2b, an acceptance of the challenge to fight a battle issued by the terminal2a, the radio relay apparatus1transmits a message for encouraging switch to the communication in the second communication mode also to the terminal2b(S106).

When the terminals2aand2bstart communication in the second communication mode, the radio relay apparatus1disconnects the Internet connection in the first communication mode over the IP network4(S107).FIG. 4illustrates a state where the Internet connection in the first communication mode is disconnected and the terminals2aand2bcommunicate each other in the second communication mode.

Note that, if the communication quality drops to below a predetermined level or at least either one of the radio terminals is handed over during communication in the second communication mode, the radio relay apparatus1may return the communication from the second communication mode to the first communication mode. The communication quality is determined based on, for example, RSSI (Received Signal Strength Indicator), SINR (Signal to Interference and Noise Ratio), FER (Flame Error Rate) and the like. When the communication quality is determined based on FER, the larger the FER value becomes, the worse the communication quality becomes, and thus the radio relay apparatus1determines, if FER is greater than the predetermined threshold, that the communication quality is below the predetermined level.

Furthermore, as a message for encouraging the terminals2aand2bto switch to the communication in the second communication mode, an ICMP (Internet Control Message Protocol) redirect message may preferably be used. The message encouraging the terminals to switch is created by adding “an identifier encouraging the communication in a second communication mode” to the option field existed in the IP header of the ICMP redirect message.

As described above, in the radio relay apparatus according to the embodiment of the present invention, the radio terminals subordinate to the radio relay apparatus can switch each other between the first communication mode and the second communication mode freely based on the communication environment, and thus the radio resource of the network is not wasted. Moreover, the radio relay apparatus according to the embodiment of the present invention communicates in the second communication mode, thereby reducing charge to the radio terminal user required for a higher radio communication in the first communication mode.

REFERENCE SIGNS LIST