Communication System, a Repeater Terminal in a Communication System and a Communication Method

A repeater terminal for repeating packet data which is sent from a transmitter terminal to a destination terminal, comprising

• a first repeating means for receiving the packet data sent from the transmitter terminal and sending the packet data to the destination terminal or another repeater terminal;
• a second repeating means for receiving a response signal sent from the destination terminal and sending the response signal to the transmitter terminal or another repeater terminal;
• and
• a determining means for determining a contribution of the repeater terminal numerically based on number of the repeating times of the packet data repeated by the first repeater means and number of the repeating times of the response signal repeated by the second repeater,
• wherein the repeater terminal enters in a repeating mode for continuously sending the packet data when the determining means determines that the contribution is high, or a numeric value for the contribution reaches a predetermined threshold or higher, and
• the repeater terminal enters in a sleep mode for repeating no packet data when the determining means determines that the contribution is low, or the numeric value for the contribution does not reach a predetermined threshold or higher.

A communication method for transmitting packet data from a transmitter terminal to a destination terminal by repeating at least one repeater terminal, comprising steps of

• transmitting the packet data from the transmitter terminal toward the destination terminal;
• receiving a response signal for the packet data transmitted at the transmitter terminal;
• transmitting a control signal including information for the transmitter terminal and the destination terminal and information for the packet data depending on presence or absence and type of the response signal;
• retransmitting the packet data which was sent after sending the control signal;
• sending a response signal for the sent packet data toward the transmitter terminal from the destination terminal;
• receiving the packet data at the repeater terminal and sending the packet data to the destination terminal or another repeater terminal from the repeater terminal;
• receiving the response signal at the repeater terminal and sending the response signal to the transmitter terminal or another repeater terminal from the repeater terminal;
• determining a contribution of the repeater terminal numerically based on number of repeating times of the packet data and number of repeating times of the response signal;
• entering in a repeating mode for continuously sending the packet data when the determining means determines that the contribution is high, or a numeric value for the contribution reaches a predetermined threshold or higher;
• and
• entering in a sleep mode for repeating no packet data when the determining means determines that the contribution is low, or the numeric value for the contribution does not reach the predetermined threshold or higher.