Patent ID: 8730061

Claim:
A method, comprising: receiving a first signal transmitted by a first road-side unit and detecting a strength of the first signal with a first on-board unit disposed at a preset position; calculating, by the first on-board unit, a calculated strength of the first signal according to the detected strength of the first signal; storing the calculated strength of the first signal in a memory accessible by the first on-board unit; receiving a second signal transmitted by a test device and detecting a strength of the second signal with the first on-board unit; calculating, by the first on-board unit, a calculated strength of the second signal according to the detected strength of the second signal; and adjusting at least one of a transmission strength of the second signal and a channel between the first on-board unit and the test device until the calculated strength of the second signal is equal to the stored strength of the first signal; wherein calculating a calculated strength of the first signal according to the detected strength of the first signal comprising: calculating the calculated strength of the first signal following an equation below: P in =(20 log(RSSI)+ x−y )− G agc where P in is the calculated strength of the first signal, RSSI is the detected strength of the first signal, G agc is a gain achieved by an automatic gain controller in the first on-board unit, x is a dBV-to-dBm conversion factor and y is a gain of an analog-to-digital conversion.