A depth and distance-based single-path routing method, in which location information of nodes in network is gathered after initialization is completed, and a location table of whole-network nodes maintained by the sink node is generated. The update mechanism of the uplink Location frame is switched to a unicast triggering update mechanism to execute a depth and energy-based uplink routing algorithm. For a downlink control packet arriving at a specified ID, location information of a node is obtained through the location table to execute a distance and energy-based downlink routing policy. The distance and energy-based downlink routing policy for a downlink control packet arriving at a specified location and a downlink control packet arriving at the specified ID is executed, and a routing recovery algorithm is executed when an “open area” occurs.

A method by a wireless network device in a wireless data network comprises: joining a non-storing mode destination-oriented directed acyclic graph (DODAG) in response to receiving a multicast DODAG information object (DIO) message originated by a root device; generating and transmitting a unicast destination advertisement (DAO) message destined for the root device and indicating the wireless network device has joined the DODAG; advertising as a subroot of a subDAG in the DODAG, based on outputting a second message specifying subDAG information identifying the subDAG; receiving a second unicast DAO message generated by a child network device in the subDAG and addressed to the wireless network device, the second unicast DAO message indicating the child network device has joined the subDAG; and generating and sending a third unicast DAO message to the root device specifying the child network device is reachable via the wireless network device.

A method by a wireless network device in a wireless data network comprises: joining a non-storing mode destination-oriented directed acyclic graph (DODAG) in response to receiving a multicast DODAG information object (DIO) message originated by a root device; generating and transmitting a unicast destination advertisement (DAO) message destined for the root device and indicating the wireless network device has joined the DODAG; advertising as a subroot of a subDAG in the DODAG, based on outputting a second message specifying subDAG information identifying the subDAG; receiving a second unicast DAO message generated by a child network device in the subDAG and addressed to the wireless network device, the second unicast DAO message indicating the child network device has joined the subDAG; and generating and sending a third unicast DAO message to the root device specifying the child network device is reachable via the wireless network device.

A communication system in which a communication apparatus includes a calculation unit configured to calculate, upon receiving a search signal from a new communication apparatus, a first time length by multiplying a first weighting time length by a relay count in a communication route to a destination, a second time length by multiplying a second weighting time length shorter than the first weighting time length by the signal strength of each communication link in the communication route, and a third time length by adding the first and second time lengths, and a transmission unit configured to transmit a response signal upon passage of the third time length from the receipt of the search signal, wherein upon receiving the response signal from one of the communication apparatuses ahead of any other response signals, the new communication apparatus sets the one of the communication apparatuses as the most adjacent relay point.

A communication system in which a communication apparatus includes a calculation unit configured to calculate, upon receiving a search signal from a new communication apparatus, a first time length by multiplying a first weighting time length by a relay count in a communication route to a destination, a second time length by multiplying a second weighting time length shorter than the first weighting time length by the signal strength of each communication link in the communication route, and a third time length by adding the first and second time lengths, and a transmission unit configured to transmit a response signal upon passage of the third time length from the receipt of the search signal, wherein upon receiving the response signal from one of the communication apparatuses ahead of any other response signals, the new communication apparatus sets the one of the communication apparatuses as the most adjacent relay point.

A method for communication between and/or determination of the movement of at least two vehicles 2a, b, c travelling in succession by means of a communication arrangement 4, wherein the communication arrangement 4 has at least one first communication apparatus 3a for arrangement on a first vehicle 2a and at least one second communication apparatus 3b for arrangement on a second vehicle 2b, is proposed, in which a signal is transmitted via a transmission path between the communication apparatuses 3a, b, c, wherein a main transmission link H of the transmission path runs at least beneath the first and/or second vehicle 2a, b and/or in which the determination of movement is carried out on the basis of the propagation time and/or propagation time differences.

In accordance with an embodiment, a network device includes a network controller and at least one network interface coupled to the network controller that includes at least one media access control (MAC) device configured to be coupled to at least one physical layer interface (PHY). The network controller may be configured to determine a network path comprising the at least one network interface that has a lowest power consumption and minimum security attributes of available media types coupled to the at least one PHY.

In accordance with an embodiment, a network device includes a network controller and at least one network interface coupled to the network controller that includes at least one media access control (MAC) device configured to be coupled to at least one physical layer interface (PHY). The network controller may be configured to determine a network path comprising the at least one network interface that has a lowest power consumption and minimum security attributes of available media types coupled to the at least one PHY.

A relay supporting multiple relay modes is provided. The relay transmits capability information to a base station, the capability information indicating support for a first relay mode and a second relay mode. The relay determines a mode of operation, either on its own or based on an indication of a mode of operation from the base station, wherein the mode of operation comprises the first relay mode or the second relay mode. The relay communicates with at least one of the base station or another wireless device based at least in part on the determined mode of operation.

Techniques are described for wireless communication. One method includes transmitting, from a first communication device, a relay search query to a plurality of relay candidates; receiving a relay search query response indicating a relay that provides at least a threshold device-to-relay-to-device (DRD) capacity for communications between the first communication device and a second communication device; and communicating with the second communication device through the indicated relay based at least in part on the relay search query response.