MULTI-HOP COMMUNICATION TERMINAL, MULTI-HOP COMMUNICATION SYSTEM, AND MULTI-HOP COMMUNICATION METHOD

• US 20140140229A1
• Filed: 09/04/2013
• Published: 05/22/2014
• Est. Priority Date: 11/16/2012
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: FUJITA, Hiroshi, OZAKI, Kazuyuki, WEN, YUN
• Granted Patent: US 9,144,006 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04W 40/08 based on transmission power
• CPC Class Codes: H04W 40/22 using selective relaying for reaching a BTS [Base Transceiver Station] or an access point
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

In a gateway (GW), when interference is detected by an interference detection unit, a frame generation unit sends an interference broadcast signal. A terminal receives the interference broadcast signal sent at a maximum transmission power from the GW to which the terminal belongs. The interference broadcast signal includes information on a planned transmission power value that is a transmission power value of a data signal in the GW and is smaller than the maximum transmission power value. The interference broadcast signal is sent at the maximum transmission power value.

Claims

1. A multi-hop communication terminal that communicates with a gateway to which the multi-hop communication terminal belongs via a communication route that is an indirect route including at least one other terminal or a direct route, the multi-hop communication terminal comprising:

a receiving unit that receives;

a first broadcast signal that is sent at a first transmission power value from the gateway to which the multi-hop communication terminal belongs and that includes information on a first planned transmission power value of a data signal in the gateway to which the multi-hop communication terminal belongs, the first planned transmission power value being smaller than the first transmission power value; and

a hello signal that includes type information and identification information of a node other than the terminal, and information on a second planned transmission power value of a data signal in the other node; and

a routing control unit that determines the communication route based on the received first broadcast signal and the received hello signal.

2. The multi-hop communication terminal according to claim 1, further comprising a power control unit that determines a second transmission power value of a data signal in the terminal based on the received first broadcast signal, the received hello signal, and the determined communication route.

3. The multi-hop communication terminal according to claim 2, further comprising a calculation unit that calculates a path loss value between the terminal and a transmission source node of the received first broadcast signal or the received hello signal based on the received first broadcast signal or the received hello signal, and calculates a required transmission power value based on the calculated path loss value and a required receiving power value;

wherein

when a second broadcast signal is not received from a gateway other than the gateway to which the multi-hop communication terminal belongs, and when the first planned transmission power value is larger than the required transmission power value between the terminal and the gateway to which the multi-hop communication terminal belongs that has been calculated by the calculation unit, the power control unit determines the first planned transmission power value as the second transmission power value.

4. The multi-hop communication terminal according to claim 2, further comprising a calculation unit that calculates a path loss value between the terminal and a transmission source node of the received first broadcast signal or the received hello signal based on the received first broadcast signal or the received hello signal, and calculates a required transmission power value based on the calculated path loss value and a required receiving power value;

wherein

when a second broadcast signal is not received from a gateway other than the gateway to which the multi-hop communication terminal belongs, and when the first planned transmission power value is smaller than the required transmission power value between the terminal and the gateway to which the multi-hop communication terminal belongs that has been calculated by the calculation unit, the routing control unit identifies a plurality of route alternatives each including, as an adjacent terminal, each of a plurality of terminals of which the required transmission power value calculated by the calculation unit is smaller than the first planned transmission power value, and sets, as the communication route, the route alternative having smallest route cost among the identified route alternatives; and

the power control unit determines the first planned transmission power value as the second transmission power value.

5. The multi-hop communication terminal according to claim 2, wherein

the receiving unit receives a second broadcast signal from a gateway other than the gateway to which the multi-hop communication terminal belongs;

the multi-hop communication terminal further comprises a calculation unit that calculates a path loss value between the terminal and a transmission source node of the received first broadcast signal, the received second broadcast signal, or the received hello signal based on the received first broadcast signal, the received second broadcast signal, or the received hello signal, and calculates a required transmission power value based on the calculated path loss value and a required receiving power value; and

the power control unit determines the second transmission power value to be a value smaller than the required transmission power value between the other gateway and the terminal that has been calculated by the calculation unit.

6. The multi-hop communication terminal according to claim 2, further comprising a calculation unit that calculates a path loss value between the terminal and a transmission source node of the received hello signal based on the received hello signal, and calculates a required transmission power value based on the calculated path loss value and a required receiving power value;

wherein

when neither the first broadcast signal from the gateway to which the multi-hop communication terminal belongs nor a second broadcast signal from a gateway other than the gateway to which the multi-hop communication terminal belongs is received, the routing control unit identifies a plurality of route alternatives each including, as an adjacent terminal, each of a plurality of terminals of which the required transmission power value calculated by the calculation unit is smaller than the second planned transmission power included in the hello signal sent from the adjacent terminal on the currently set communication route, and sets, as the communication route, the route alternative having smallest route cost among the identified route alternatives.

7. A multi-hop communication system comprising:

a gateway to which a multi-hop communication terminal belongs; and

the multi-hop communication terminal that communicates with the gateway via a communication route that is an indirect route including at least one other terminal or a direct route, wherein

the gateway to which the multi-hop communication terminal belongs comprises;

a detection unit that detects interference based on a signal sent from a node other than a first hop terminal communicating with the gateway via a direct route, and identifies the interfering node;

a transmission unit that sends;

a first broadcast signal that is sent at a first transmission power value when the interference is detected and that includes information on a first planned transmission power value of a data signal in the gateway, the first planned transmission power value being smaller than the first transmission power value; and

a first hello signal that includes type information and identification information of the node of the gateway, and information on a second planned transmission power value of a data signal in the node;

a first receiving unit that receives a second broadcast signal sent from a gateway other than the gateway and a second hello signal sent from a node other than the gateway; and

a power control unit that determines a second transmission power value of the data signal in the gateway based on the second broadcast signal received by the first receiving unit or on the second hello signal from the other gateway received by the first receiving unit; and

the multi-hop communication terminal comprises;

a second receiving unit that receives the first broadcast signal and a hello signal from a node other than the terminal; and

a routing control unit that determines the communication route based on the first broadcast signal and the hello signal received by the second receiving unit.

8. The multi-hop communication system according to claim 7, wherein

the gateway to which the multi-hop communication terminal belongs comprises a calculation unit that calculates a path loss value between the gateway and a transmission source node of the second broadcast signal or the hello signal received by the first receiving unit based on the second broadcast signal or the hello signal received by the first receiving unit, and calculates a required transmission power value based on the calculated path loss value and a required receiving power value;

and

the power control unit assumes, as the lower limit value of the second transmission power value, a minimum value among required transmission power values each of which is calculated by the calculation unit for each of a plurality of multi-hop communication terminals.

9. The multi-hop communication system according to claim 7, wherein the transmission unit sends the first broadcast signal each time the detection unit detects interference by any interfering node, and, when the number of times of transmission of the first broadcast signal based on the interference by the interfering node exceeds a certain value, excludes the first broadcast signal based on the interference by the interfering node from signals to be retransmitted.

10. A multi-hop communication method by a terminal communicating with a gateway to which the terminal belongs via a communication route that is an indirect route including at least one other terminal or a direct route, the multi-hop communication method comprising:

receiving by a receiver;

a broadcast signal that is sent at a first transmission power value from the gateway to which the terminal belongs and that includes information on a first planned transmission power value of a data signal in the gateway to which the terminal belongs, the first planned transmission power value being smaller than the first transmission power value; and

a hello signal that is sent from a node other than the terminal and that includes type information and identification information of the other node, and information on a second planned transmission power value of a data signal in the other node; and

determining, by a processor, the communication route based on the received first broadcast signal and the received hello signal.