Patent ID: 8289963
Filing Date: 2012-10-16
Classification: H04W

Abstract:
1. A process for calculating distances between wireless nodes, comprising: a) sending, from a wireless node to be positioned, a request data packet or frame, to a reference wireless node, with a known position; b) receiving, in said node to be positioned, a response data packet or frame, sent by said reference node after receiving said request data frame; c) calculating the time elapsed between said sending of stage a) and said reception of stage b), or round trip time; and d) calculating the distance between both wireless nodes from said calculated elapsed time, wherein the process further comprises, for the purpose of determining said round trip time in the node to be positioned: providing, in said node to be positioned, a time-stamping software layer above the physical layer, in an OSI stack, and using it to assign and register timestamps to at least part of the inputs and outputs of data frames received and to be sent by said node to be positioned; processing, by means of a link software layer of said OSI stack of the node to be positioned, the data frames received and to be sent by the latter; and providing a binding software layer, above said link software layer, and using it to: access the timestamps registered by means of said time-stamping software layer, access the data frames to be sent, prior to their passage through the link software layer, and the data frames received, once processed by the link software layer, and bind the corresponding timestamps with at least the request data frame to be sent in stage a) and the response data frame received in stage b).