US 6,307,878 B1 · Cellular telephony searcher

Abstract

A searcher for a mobile station of a cellular telephony network. Pilot signal from nearby base stations are correlated with a pseudonoise sequence inside a search window, using a bank of correlators. Each correlator is assigned a different delay, from among a sequence of delays in the window. At each delay, correlation is performed initially for a first dwell time. If the resulting correlation value exceeds a threshold, the correlation is continued for a second dwell time. Otherwise, the correlator is set to the next delay in the sequence. Only the outputs of second dwell correlations are used to identify the nearest base station. Some correlators may perform first dwell correlations at new delays in the window at the same time that other correlators are still performing second dwell correlations at old delays in the window.

Claims23

Dependent claims

A cellular telephony searcher, comprising:

a plurality of correlators for correlating a received signal with a pseudonoise sequence;
an input mechanism for inputting said pseudonoise sequence into said correlators, each of said correlators receiving said pseudonoise sequence with a different delay;
and
a delay management mechanism for initializing said delays and subsequently changing said delays, said changing being contingent, for each said correlator, only on an output of said each correlator.

1 more element

In a cellular telephony network including at least one base station and at least one mobile station, each of the at least one mobile station receiving a received signal from the at least one base station, the received signal including a plurality of received values, each said received value having a real part and an imaginary part, a method for each of the at least one mobile station to identify at least one multipath channel to use to communicate with one of the at least one base station, comprising:

generating a pseudonoise sequence;
simultaneously performing a plurality of initial correlations of the received signal with said pseudonoise sequence, each of said initial correlations being performed with a different initial delay of said pseudonoise sequence, said initial correlations being performed for a first dwell time to produce, for each of said initial correlations, an initial first dwell time correlation value;
and
for each said initial correlation:
if an estimated absolute value of said initial first dwell time correlation value exceeds a threshold, continuing to perform said each initial correlation,
otherwise, performing a first subsequent correlation of the received signal with said pseudonoise sequence at a first subsequent delay different from any of said initial delays;
wherein, if said performing of at least one of said initial correlations is continued and if at least one of said first subsequent correlations is performed, said continued performing of said at least one initial correlation and said performing of said at least one first subsequent correlation are effected simultaneously.

4 more elements

Dependencies are inferred from the claim text.

Cellular telephony searcher

Life of this patent

Cellular telephony searcher

Life of this patent

Abstract

Claims23