US 7,321,645 B2
Method and arrangement for detecting a random access channel preamble using multiple antenna reception in a communication system
Jung Ah Lee, Pittstown, N.J. (US); and Anil M. Rao, Randolph, N.J. (US)
Assigned to Lucent Technologies Inc., Murray Hill, N.J. (US)
Filed on Aug. 29, 2003, as Appl. No. 10/651,200.
Prior Publication US 2005/0047530 A1, Mar. 03, 2005
Int. Cl. H03D 1/00 (2006.01); H04L 27/06 (2006.01)
U.S. Cl. 375—343  [375/134; 375/136; 375/137; 375/142; 375/145; 375/147; 375/150] 20 Claims
OG exemplary drawing
 
1. 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.