Patent ID: 7321645

Claim:
A method of detecting a random access channel preamble in a received uplink signal from a user, comprising: spatially processing and temporally processing an uplink signal received at one or more receive antennas of a base station receiver and containing data related to a random access channel preamble to detect the random access channel preamble, wherein temporal processing includes: temporally correlating the received uplink signal to output at least one subcorrelation output signal, determining, for each subcorrelation output signal, a decision statistic as the magnitude squared of the subcorrelation output signal, and comparing a maximum of the determined decision statistics to a threshold value, the random access channel preamble of the uplink signal having been detected if the maximum decision statistic meets or exceeds the threshold value, and determining the threshold value so that as the number of antenna beams for a given angle of arrival of the received uplink signal increase, the threshold value increases so as to maintain a probability of false alarm over all antenna beams to a desired value, wherein the probability of false alarm is a probability that the uplink signal is falsely detected when no random access channel preamble has been transmitted by the user.