Abstract: A method for mitigating the effect of interference between a first base station and a second base station, the first base station and second base stations both sharing a same primary synchronization code. The method includes generating a primary synchronization channel having the primary synchronization code. In a W-CDMA system, all base stations share this primary synchronization code, causing code timing collisions. The present invention includes rotating the primary synchronization channel in phase according to a phase rotation sequence before transmitting the primary synchronization channel. By rotating the primary synchronization channel in phase according to the phase rotation sequence, the interference can be reduced. The phase rotation sequence may be pseudorandom in phase. The phase rotation sequence may include changing phase once per slot, or alternately once per frame. The phase rotation sequence may also be based at least in part on a secondary synchronization code.

Abstract: Techniques for searching in asynchronous systems are disclosed. In one aspect, a plurality of codes, such as SSCs, are correlated with a received signal at a plurality of offsets to produce a code/slot energy corresponding to each code/slot boundary pair. Unique subsets of the code/slot energies are summed to produce code sequence energies, the maximum of which indicates a located code sequence and slot boundary. In another aspect, the correlation is performed by sub-correlating the received signal with a common sequence, and performing a Fast Hadamard Transform (FHT) on the results. In yet another aspect, one sub-correlator can be used to search a plurality of peaks simultaneously. Various other aspects of the invention are also presented.

Abstract: Techniques for efficient W-CDMA modulation are disclosed. In one aspect, a multiplexing/coding chain for use in modulation such as that defined by the W-CDMA specification is disclosed. In another aspect, transport blocks are processed and concatenated, utilizing memory efficiently. This aspect has the further benefit of preparing transport channels for efficient subsequent processing. It also allows for ease of interface with the transport channel source. In another aspect, the use of repeated channel coding is used in lieu of an interleaver memory to provide channel coding and interleaving. These aspects, collectively, yield the advanced benefits of a system, such as W-CDMA, in a hardware efficient manner. The techniques described herein apply equally to both access points and access terminals. The techniques are not limited to W-CDMA systems; they are quite suitable to other systems requiring the various benefits the invention offers. Various other aspects of the invention are also presented.

Abstract: A wideband code division multiple access system supports asynchronous operation, with each base station having its own time reference. Substantial benefits may be realized by operating the WCDMA system in a quasi-synchronous mode, in which the base stations broadcast the relative time difference between their time references and the time references of their neighbor base stations. The WCDMA system supports techniques for measuring the relative time difference.

Abstract: Techniques for fast-slewing of multi-sequence based PN generators are disclosed. In one aspect, LFSR states and reference counter states are loaded into their corresponding components such that consistency among the states is maintained. In another aspect, various methods for determining LFSR states and counter values in response to a desired offset in a unique code are disclosed. Among these methods are matrix-multiplication of LFSR states and generation of advanced LFSR states through masking techniques. Other methods are also presented. These aspects have the benefit of decreasing slew time in an efficient manner, which translates to increased acquisition speed, faster finger lock on multi-path signals, increased data throughput, decreased power, and improved overall system capacity.

Abstract: In a CDMA system in which the base stations are not each time aligned with one another, the handoff process accommodates the handoff by allowing for frame alignment. For example, frame alignment may be accomplished through the use of a selected set or may be remote unit aligned without reference to external sources. In addition, the neighbor list may included additional entries.

Abstract: In a CDMA system in which the base stations are not each time aligned with one another, the handoff process accommodates the handoff by allowing for frame alignment. For example, frame alignment may be accomplished through the use of a selected set or may be remote unit aligned without reference to external sources. In addition, the neighbor list may included additional entries.

Abstract: The invention is a method for limiting the peak transmit power in a CDMA communication system. At least one of first and second high transmit power regions are separated into a plurality of high transmit power subregions. The high transmit power subregions of the plurality of high subregions are shifted by time offsets of differing durations to provide a plurality of time offset subregions. First and second low transmit power regions are also provided. At least one of the first and second low transmit power regions is also separated into a plurality of transmit power subregions and the low transmit power subregions are shifted by time offsets of differing time durations. The subregions can be time offset by a predetermined time duration or by a random time duration.

Abstract: The invention is a method for limiting the peak transmit power in a CDMA communication system including the steps transmitting a first communication signal having a first high transmit power region and transmitting a second communication signal having a second high transmit power region. One of the first and second communication signals is time offset to prevent the first and second high transmit power regions from occurring simultaneously. Time shifting only a portion of one of the first and second communications signals is also taught. The first and second communication signals can also include respective first and second low transmit power regions. The time offset can be selected to align one of the first and second high transmit power regions with one of the first and second low transmit power regions.

Abstract: The invention is a method for limiting the peak transmit power in a CDMA communication system. At least one of first and second high transmit power regions are separated into a plurality of high transmit power subregions. The high transmit power subregions of the plurality of high subregions are shifted by time offsets of differing durations to provide a plurality of time offset subregions. First and second low transmit power regions are also provided. At least one of the first and second low transmit power regions is also separated into a plurality of transmit power subregions and the low transmit power subregions are shifted by time offsets of differing time durations. The subregions can be time offset by a predetermined time duration or by a random time duration.

Abstract: A method for limiting the peak transmit power in a CDMA communication system including the steps transmitting a first communication signal having a first high transmit power region and transmitting a second communication signal having a second high transmit power region. One of the first and second communication signals is time offset to prevent the first and second high transmit power regions from occurring simultaneously. Time shifting only a portion of one of the first and second communications signals is also taught. The first and second communication signals can also include respective first and second low transmit power regions. The time offset can be selected to align one of the first and second high transmit power regions with one of the first and second low transmit power regions. The total transmit power signal can be determined and the time offset can be selected according to the total transmit power signal to minimize a peak level of the total transmit power signal.

Abstract: A method for mitigating the effect of interference between a first base station and a second base station, the first base station and second base stations both sharing a same primary synchronization code. The method includes generating a primary synchronization channel having the primary synchronization code. In a W-CDMA system, all base stations share this primary synchronization code, causing code timing collisions. The present invention includes rotating the primary synchronization channel in phase according to a phase rotation sequence before transmitting the primary synchronization channel. By rotating the primary synchronization channel in phase according to the phase rotation sequence, the interference can be reduced. The phase rotation sequence may be pseudorandom in phase. The phase rotation sequence may include changing phase once per slot, or alternately once per frame. The phase rotation sequence may also be based at least in part on a secondary synchronization code.

Abstract: Several methods and corresponding apparatus reduce peak to average power in signals transmitted in a wireless communications system, particularly with respect to pilot symbols transmitted from a base station to several user stations. A large peak to average amplitude of inserted pilot symbols has been found to result from a common sign chip position that exists in orthogonal codes, such as Walsh codes. In a first embodiment, the Walsh codes are multiplied by a random value of ±1. Under a second embodiment, the common sign chip position is eliminated in each Walsh code. The user station then inserts the missing chip position to regain orthogonality. In a third embodiment, the base station transmits pilot symbols, on a separate pilot channel, in only symbol positions that user stations expect to find pilot symbols. Under a fourth embodiment, each Walsh code is randomly shifted.

Abstract: The invention is a method for limiting the peak transmit power in a CDMA communication system. At least one of first and second high transmit power regions are separated into a plurality of high transmit power subregions. The high transmit power subregions of the plurality of high subregions are shifted by time offsets of differing durations to provide a plurality of time offset subregions. First and second low transmit power regions are also provided. At least one of the first and second low transmit power regions is also separated into a plurality of transmit power subregions and the low transmit power subregions are shifted by time offsets of differing time durations. The subregions can be time offset by a predetermined time duration or by a random time duration.

Abstract: Several methods and corresponding apparatus reduce peak to average power in signals transmitted in a wireless communications system, particularly with respect to pilot symbols transmitted from a base station to several user stations. A large peak to average amplitude of inserted pilot symbols has been found to result from a common sign chip position that exists in orthogonal codes, such as Walsh codes. In a first embodiment, the Walsh codes are multiplied by a random value of ±1. Under a second embodiment, the common sign chip position is eliminated in each Walsh code. The user station then inserts the missing chip position to regain orthogonality. In a third embodiment, the base station transmits pilot symbols, on a separate pilot channel, in only symbol positions that user stations expect to find pilot symbols. Under a fourth embodiment, each Walsh code is randomly shifted.

Abstract: The invention is a method for limiting the peak transmit power in a CDMA communication system. At least one of first and second high transmit power regions are separated into a plurality of high transmit power subregions. The high transmit power subregions of the plurality of high subregions are shifted by time offsets of differing durations to provide a plurality of time offset subregions. First and second low transmit power regions are also provided. At least one of the first and second low transmit power regions is also separated into a plurality of transmit power subregions and the low transmit power subregions are shifted by time offsets of differing time durations. The subregions can be time offset by a predetermined time duration or by a random time duration.

Abstract: A method and system that enables faster acquisition of the forward link signal of a target base station in a mixed network of synchronous and asynchronous base stations is disclosed. The serving base station transmits in a neighbor list an estimated timing error 417 between the serving base station and a target base station. By utilizing the timing information, a mobile station estimates the relative time offset 408 between forward link signals received from the serving base station and signals received from the target base station. Timing information acquired during handoff enables accurate updating of the estimated timing error 417 subsequently transmitted in the neighbor lists by the base stations.

Abstract: A method and system that enables faster acquisition of the forward link signal of a target base station in a mixed network of synchronous and asynchronous base stations is disclosed. The serving base station transmits in a neighbor list an estimated timing error 417 between the serving base station and a target base station. By utilizing the timing information, a mobile station estimates the relative time offset 408 between forward link signals received from the serving base station and signals received from the target base station. Timing information acquired during handoff enables accurate updating of the estimated timing error 417 subsequently transmitted in the neighbor lists by the base stations.