Abstract: A handoff technique in which system users detect transitions in service between a current service area and an adjacent service area, and request a forward link channel in the new service area when a detected signal strength for the new service area exceeds predetermined threshold levels. The forward communications link in the current service area is maintained until the strength of the new service area signal reaches a certain level and appropriate channel quality is confirmed, as based on various known criteria. Typically, service area transitions are detected using the signal strength of pilot or paging signals associated with service areas, which are used to determine a relative signal strength of new service area signals. Pilot signal level adjustments used to counter roll-off effects are detected and compensated for in comparing signal levels.
Abstract: A system and method for estimating the power of a signal. The signal is compared to and separated into a plurality of ranges. Each range is assigned a particular output value. The output values approximate the square of the input signal based on known characteristics of the input signal. A low pass filter is used to average a plurality of the output values.
Abstract: A technique for spreading information signals in a spread spectrum communication system to provide increased signal acquisition speed. A first PN spreading code or code set is used to spread information signals along with a second PN spreading code sequence or function. The second PN code is synchronized with the first PN spreading code, but has a larger code period so that each code chip of the second PN code extends over the entire period of the first PN code. The longer period spreading code forms an outer code which helps provide unambiguous beam identification and easily acquired frame timing in the presence of dynamically changing signal path delay, improving signal acquisition.
Type:
Grant
Filed:
October 9, 1998
Date of Patent:
December 10, 2002
Assignee:
Qualcomm, Inc.
Inventors:
Brian Harms, Brian Butler, Gordon Skinner
Abstract: A method for reducing the number of required frequency and time hypotheses to acquire an access transmission in a satellite communication system. By reducing the number of required hypotheses, the amount of hardware required to acquire the access transmission is reduced. The method of the present invention reduces the number of required hypotheses by reducing the range of possible frequency and timing values of the access transmission. The range of possible frequency and timing values is reduced by determining the frequency and time uncertainties over individual satellite beams rather than over an entire satellite footprint.
Type:
Grant
Filed:
August 27, 1998
Date of Patent:
April 30, 2002
Assignee:
Qualcomm Incorporated
Inventors:
Ananthanarayanan Chockalingam, Nathan E. Tenny, David S. Miller