Patent ID: 7949036

Claim:
A method of generating a detection signal for detecting energy in a received spread spectrum communications signal, the method comprising: de-spreading a received spread spectrum communications signal by applying at least one predetermined spreading code from a set of spreading codes to obtain a sequence of de-spread signal symbols; obtaining at least a first and a second subset of said de-spread symbols, wherein the de-spread signal symbols of the first subset have values that are either known to the receiver or at least known to be the same for all de-spread signal symbols of the first subset, and wherein the de-spread signal symbols of the second subset have values unknown to the receiver; coherently accumulating the de-spread signal symbols of the first subset to obtain a first partial detection signal; accumulating a predetermined number of said de-spread signal symbols to obtain a first detection signal; buffering at least one of the received spread spectrum signal and the sequence of de-spread signal symbols as a buffered signal; decoding a predetermined block of the de-spread signal symbols to obtain a set of decoded data; processing the decoded data to reconstruct a corresponding block of transmitted signal symbols; performing the steps of buffering, decoding, processing the decoded data, and generating a coherently accumulated detection signal with respect to the second subset of de-spread data symbols to obtain a second partial detection signal; combining the first and second partial detection signals to obtain a single detection signal; and generating a coherently accumulated detection signal from the buffered signal and the reconstructed transmitted signal symbols.