Patent ID: 9596650
Date: 2017-03-14
CPC Classifications: H04W,Y02D

Claim:
1. A method of establishing communication between a primary node and one or more secondary nodes over one or more communications channels, wherein the secondary nodes are placed in a sleep state in the absence of active communications and are responsive to a wake-up message transmitted over the one or more communications channels from the primary node to enter a wake-up state to permit the establishment of active communications, the method comprising: sending a wake-up message from an instigator at the primary node to a receptor at a said secondary node; periodically sniffing said one or more communications channels with the receptor at said secondary node for a valid wake-up message; in response to reception of a valid wake-up message said receptor placing said secondary node in the wake-up state; said instigator and receptor employing a selected one of a plurality of operational modes, said operational modes being defined by the timing of the wake-up message and sniff pattern at the receptor; monitoring channel conditions in said one or more communication channels; and in response to said monitoring of said channel conditions changing said selected operational mode to suit different channel conditions, wherein said selected mode is changed at the receptor in response to a mode change instruction signal received from the instigator.