Patent ID: 9220047
Filing Date: 2015-12-22
Classification: H04W

Abstract:
1. A network system comprising: one core node; and a plurality of slave nodes, wherein the core node transmits data packets to the plurality of slave nodes periodically and intermittently, each of the slave nodes includes: a plurality of directional antennas; communication control unit that, when the slave node has uplink data packets to be transmitted to the core node and then receives downlink data packets from an uplink node, transmits the uplink data packets to the uplink node that has transmitted the downlink data packets by using a directional antenna through which the downlink data packets were received; and an antenna control unit that activates all or a part of the plurality of directional antennas, and in a reception waiting state, the antenna control unit of each of the slave nodes activates at least one directional antenna serving for receiving the downlink data packets from the uplink node and does not forward the uplink data packets, and upon receiving downlink data packets transmitted from the core node, when the slave node has the uplink data packets, the antenna control unit of the slave node transmits the uplink data packets to the uplink node that has transmitted the downlink data packets by using the directional antenna through which the downlink data packets were received, and if received downlink data packets contain a downlink forwarding data packet to be transmitted to another slave node, the antenna control unit of the slave node immediately generates a transmission event, activates at least one directional antenna serving for forwarding the downlink forwarding data packet, forwards the downlink forwarding data packet, receives uplink data packets, for the reception waiting state, activates the directional antenna for receiving the downlink data packets, and does not forward the uplink data packets.