US Patent 10172025 Methods and systems for a ranging protocol

Disclosed are methods, systems and devices for obtaining a range between devices based, at least in part, on an exchange of wireless messages. For example, wireless devices may obtain measurements of range based, at least in part, on an exchange fine timing measurement (FTM) messages. In one implementation, an initiating wireless station may transmit an initial FTM request message comprising one or more fields to a responding wireless station specifying an indefinite duration for a requested session to transmit FTM messages to the initiating wireless station.