Ad hoc communications system

A network of wireless relay devices comprising:

• a plurality of mobile wireless relay devices capable of receiving payload data,
• each said device comprising means for identifying a forwarding direction relative to itself, and means for transmitting data to another of the devices whose current position is in the said forwarding direction and within a predetermined distance,
• wherein the devices co-operate to define their forwarding directions such that payload data is transmitted to a target sink device by means of one or more of the wireless relay devices,
• each device defines a positive receive node and a negative transmit node, spaced a pre-determined distance apart, and
• the devices co-operate to define the positions of the nodes so as to the minimize aggregate distances between nodes having opposite signs, and
• the forwarding direction of each device is defined as the direction from its receive node in which its transmit node lies.

A method of operating a plurality of mobile data wireless relay devices, said method comprising:

• collecting data in buffer stores in one or more such devices;
• exchanging status data between the devices, the status data comprising data relating to:
• the positions of the devices, and
• the quantity of data in their buffer stores;
• each device defining, from the status data, a forwarding direction towards which the pay-load data in its buffer store is to be forwarded;
• and
• transmitting the stored payload data to a device located in the forwarding direction,
• wherein each device defines a first node and a second node, the nodes being spaced apart by a distance determined by the amount of data stored in the buffer, the first node being assigned a positive value for an attribute q and the second node being assigned a negative value for the attribute q, equal in magnitude to that assigned to the positive node;
• position values are generated for the first and second nodes based on the status data of the device and neighboring devices;
• transmitting the position data and attribute values to similar wireless relay devices;
• and
• transmitting payload data to devices that are in the general direction of the second node.