Abstract: A communication system including a closed loop power control system. Prior to allowing a handoff to a new base station, the subscriber station verifies that its reverse link signal is being received by the destination base station with sufficient energy. The determination is made based on the received reverse link power control commands from the base station. Moreover, a handoff may be forced when the base station providing the best forward link signal is not receiving the reverse link signal from the subscriber station with sufficient energy.
Abstract: Independently controlling the transmitted power of each subchannel by a subchannel control loop is described. A transmitting station generates a channel made up of a sum of subchannels wherein each subchannel or group of subchannels is amplified with a unique gain value that is varied in accordance with subchannel power control messages from the receiving station. The receiving station generates each subchannel power control message subsequent to monitoring and calculating metrics based on that received subchannel.
Abstract: A novel and improved method and apparatus for coherently processing a CDMA signal without the use of pilot or other synchronization information is described. By utilizing a coherent receive processing system, a reverse link signal can be properly processed when received at a lower power level than that associated with noncoherent only processing. This reduces the transmit power necessary for successful communication, and this reduction in necessary transmit power reduces the degree to which a set of subscriber units communicating with the same base station interfere with one another. In turn, this increases the overall system capacity of a CDMA wireless telecommunication system incorporating the invention.
Type:
Grant
Filed:
July 29, 1996
Date of Patent:
November 16, 1999
Assignee:
Qualcomm Inc.
Inventors:
Ephraim Zehavi, Serge Willenegger, Joseph P. Odenwalder
Abstract: The present invention provides a method and apparatus for providing improved power control in a closed-loop communication system. A base station monitors a quality of a feedback link between it and a mobile station under a variety of methods. When a quality of the feedback link becomes unacceptable, the base station and the mobile station enter into an alternative mode of operation, adjusting from a fast power control feedback mode (with a high bandwidth feedback channel and low power control delay), to a slow power control feedback mode (with a low bandwidth feedback channel or a long power control delay). The mobile station adjusts a rate or content of power control messages it feeds back to the base station under a variety of methods. Under this alternative mode, the mobile station increases a power of its feedback signals. Additionally, if the mobile station is in a soft handoff condition, it similarly increases a power of its feedback signals.
Abstract: The present invention is a novel and improved method and apparatus for decoding a frame of digital data which contains redundant information provided to validate the decoding operation. In the present invention, a frame of data contains information bits and cyclic redundancy check (CRC) bits. The received frame is decoded and a check is conducted to determine whether the CRC bits correspond correctly for the decoded information bits. If the decoded frame passes the CRC test process, the decoded fame is provided to the user. However, if the decoded frame does not pass the CRC test, then at least one additional decoding process is performed on the received frame. In the first exemplary embodiment of the present invention, if the CRC test is failed, a noise vector of a predetermined set of noise vectors is summed with the received frame and the resultant frame is decoded for a second time.