ROUND TRIP TIME (RTT) DETERMINATION

摘要

Techniques disclosed can help mitigate errors due to clock drift in the determination of round trip time (RTT) from a message exchange between two mobile stations. The techniques involve reducing the time (and, therefore, the drift) over which RTT is computed. Such techniques can be used with clock-synchronizing and/or other methods for reducing RTT errors to provide RTT calculations far more accurate than traditional methods.

主权项

1. A method of calculating round trip time (RTT) from a first wireless device to a second wireless device, the method comprising:
sending, with the first wireless device, a first message; determining a first timestamp, indicative of an end of a period of time over which the first wireless device sent the first message; receiving, with the first wireless device, a second message sent by the second wireless device in response to the first message; determining, with the first wireless device:
a second timestamp, indicative of an end of a period of time over which the second wireless device received the first message, anda third timestamp, indicative of a beginning of a period of time over which the second wireless device sent the second message; determining a fourth timestamp, indicative of a beginning of a period of time over which the first wireless device received the second message; and determining the RTT from the first wireless device to the second wireless device, wherein determining the RTT is based, at least in part, on the first timestamp, the second timestamp, the third timestamp and the fourth timestamp.