Patent ID: 7254170

Claim:
A noise measurement method comprising: determining that a short-spreading-factor code is unoccupied, wherein the short-spreading-factor code has a short spreading factor that is less than a longest spreading factor; measuring a first symbol energy based on the short-spreading-factor code to provide a first measured symbol energy; measuring a second symbol energy based on the short-spreading-factor code to provide a second measured symbol energy; generating a first noise estimate based on a difference between the first measured symbol energy and the second measured symbol energy; determining that a second of the two longest-spreading-factor codes is unoccupied at a predetermined duty-cycle; measuring a third symbol energy based on the short-spreading-factor code to provide a third measured symbol energy; measuring a fourth symbol energy based on the short-spreading-factor code to provide a fourth measured symbol energy; and generating a second noise estimate based on a difference between the third measured symbol energy and the fourth measured symbol energy, wherein the measuring a first symbol energy, the measuring a second symbol energy, the measuring a third symbol energy, and the measuring a fourth symbol energy occur respectively in four consecutive code symbol periods existing within a longest code symbol period associated with a longest code symbol having the longest spreading factor.