Abstract: In a remote unit of a wireless communication system, the speed of acquisition, or reacquisition, of a pilot signal by a search engine is increased. PN space is divided into segments and a coarse search of each segment is performed using a set of “fast” search parameters. A set of peak signal strengths, along with their corresponding PN offsets, is saved for each segment of PN space. Following the search of all segments of PN space, the peak signal strengths which were saved during the coarse acquisition are evaluated. Coarse acquisition search results are used by the remote unit to determine fine search window parameters for subsequent searches performed by the remote unit search engine. The fine search parameters concentrate searching efforts on portions of PN space most likely to contain a viable base station pilot signal.

Abstract: Methods and apparatus are provided for increasing throughput in a wireless communication system by reducing the amount of overhead transmitted to certain user terminals. Overhead due to control information may be reduced for these certain user terminals by selecting a low repetition factor. Overhead may be further reduced for these certain user terminals by selecting a modulation/coding scheme with a higher data rate for transmitting the control information. The selection may be based on channel conditions associated with the user terminals, such as signal-to-interference-plus-noise ratios (SINRs).

Abstract: Certain embodiments of the present disclosure provide a method for scanning for paging messages in a second radio access technology (RAT) network, such as a CDMA network, while connected to a first RAT network, such as a WiMAX network. For certain embodiments, an enhanced scanning request message may facilitate establishing a scanning cycle in the first RAT that aligns with a paging cycle of the second RAT.

Abstract: Systems and techniques are disclosed detecting an embedded signal which includes producing a plurality of first correlated values from a portion of the first signal and a second signal, transforming the first correlation values into a plurality of second correlation values related to a frequency content of the first correlation values, and searching for the embedded signal by evaluating the second correlation values. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

Abstract: A method and apparatus for decoding encoded data bits of a wireless communication transmission are provided. A set of a-priori bit values corresponding to known bit values of the encoded data bits may be generated. Decoding paths that correspond to decoded data bits that are inconsistent with the a-priori bit values may be removed from the possible decoding paths to consider, and decoding the encoded data bits by selecting a decoding path from remaining decoding paths of the possible decoding paths that were not removed. Multiple hypotheses, each corresponding to a different set of a-prior bit values may be evaluated, with the decoded data for a hypothesis selected based on the evaluation output for further processing.

Abstract: A method and apparatus for combining retransmitted hybrid automatic repeat-request (HARQ) messages divided into coding blocks in an orthogonal frequency-division multiplexing (OFDM)/orthogonal frequency-division multiple access (OFDMA) receiver are provided. According to such a coding-block-based HARQ combining scheme, the quality of each coding block may be compared to a threshold to determine whether the decoded bits or the HARQ combined signal should be saved for each coding block for subsequent HARQ iterations. In addition to reducing the required HARQ buffer size while preserving the combining gain, coding-block-based HARQ combining may also provide fast decoding and reduced power consumption when compared to conventional HARQ combining techniques.

Abstract: A method and apparatus for combining retransmitted hybrid automatic repeat-request (HARQ) messages at different stages in an OFDM/OFDMA receiver are provided. A combination of different types of HARQ combiners may be designed into the receiver and selected on a per-channel basis. Proper selection of a HARQ combining scheme may reduce the required HARQ buffer size and may provide an increased combining gain when compared to conventional HARQ combining techniques. Furthermore, the HARQ combiner type may be dynamically selected through forward and reverse shifting between the different types of HARQ combining schemes in an effort to decrease the bit error ratio (BER) without saturating the HARQ buffer.

Abstract: Techniques for detecting and suppressing jammers are described. A receiver may perform post-FFT jammer detection and pre-FFT jammer suppression. The receiver may transform an input signal to obtain a frequency-domain signal and may detect for jammers in the input signal based on the frequency-domain signal. The receiver may determine powers of a plurality of carriers based on the frequency-domain signal and may detect for jammers based on peaks in the powers of these carriers. The receiver may filter the input signal (e.g., with a notch filter) to suppress the detected jammers. Alternatively or additionally, the receiver may perform post-FFT jammer detection and post-FFT jammer suppression. The receiver may determine whether jammer is present on each carrier based on data power and channel power for that carrier. The receiver may modify (e.g., zero out or reduce) the frequency-domain signal on carriers with detected jammers.

Abstract: Interoperability between wireless communication systems, such as the IS2000-1x and IS856 systems, is facilitated by using supervision timers. A wireless communication device starts one or more supervision timers and performs an intersystem transition. When the wireless communication device returns from the transition, the supervision timers are used to estimate the duration of the transition. The wireless communication device then performs a sequence of tasks appropriate to the estimated duration.

Abstract: An efficient method and apparatus for implementing a back-end channel matched filter in a receiver is disclosed. A typical channel matched filter embodiment includes a peak detector for establishing processing synchronization from a despread signal, a channel estimator producing a channel impulse response (CIR) estimate from the despread signal based on the synchronization by the peak detector and a back-end symbol combiner coherently combining dominant multipath components of the despread signal by weights based on the CIR estimate based on the synchronization by the peak detector to generate a decision variable. In a digital spread spectrum implementation, the despread signal operated on by the channel matched filter has been previously been correlated with a spreading sequence replica.

Abstract: Interoperability between wireless communication systems, such as the IS2000-1x and IS856 systems, is facilitated by using supervision timers. A wireless communication device starts one or more supervision timers and performs an intersystem transition. When the wireless communication device returns from the transition, the supervision timers are used to estimate the duration of the transition. The wireless communication device then performs a sequence of tasks appropriate to the estimated duration.

Abstract: A decision feedback equalizer includes a chip estimate buffer that forms chip estimates into a vector. A CCK decoder decodes the vector of chip estimates, and a CCK encoder, connected with the CCK decoder, re-encodes the vector of chip estimates into a valid CCK code word. At the same time, a chip slicer provides direct sliced chips from the chip estimates. An update module then forms a hybrid vector from the valid CCK code-word and the direct sliced chips for input to the feedback filter of the decision feedback equalizer. The hybrid feedback filter input vector reflects the CCK coding gain of its re-encoded portion thereby reducing the estimated chip error rate to improve the performance of the decision feedback equalizer.

Abstract: In a remote unit of a wireless communication system, the speed of acquisition, or reacquisition, of a pilot signal by a search engine is increased. PN space is divided into segments and a coarse search of each segment is performed using a set of “fast” search parameters. A set of peak signal strengths, along with their corresponding PN offsets, is saved for each segment of PN space. Following the search of all segments of PN space, the peak signal strengths which were saved during the coarse acquisition are evaluated. Coarse acquisition search results are used by the remote unit to determine fine search window parameters for subsequent searches performed by the remote unit search engine. The fine search parameters concentrate searching efforts on portions of PN space most likely to contain a viable base station pilot signal.

Abstract: In a remote unit of a wireless communication system, the speed of acquisition, or reacquisition, of a pilot signal by a search engine is increased. PN space is divided into segments and a coarse search of each segment is performed using a set of “fast” search parameters. A set of peak signal strengths along with their corresponding PN offsets, is saved for each segment of PN space. Following the search of all segments of PN space, the peak signal strengths which were saved during the coarse acquisition are evaluated. Coarse acquisition search results are used by the remote unit to determine fine search window parameters for subsequent searches performed by the remote unit search engine. The fine search parameters concentrate searching efforts on portions of PN space most likely to contain a viable base station pilot signal.

Abstract: Techniques for performing time tracking at a receiver are described. A first arriving path (FAP) and a last arriving path (LAP) are detected based on a channel impulse response estimate for a communication channel. The detected FAP and LAP may be correct or swapped. To resolve ambiguity in the detected FAP and LAP, a first hypothesis corresponding to the FAP and LAP being correctly detected and a second hypothesis corresponding to the FAP and LAP being incorrectly detected are evaluated. For each hypothesis, hypothesized FAP and LAP are determined based on the detected FAP and LAP, a correlation window is determined based on the hypothesized FAP and LAP, and correlation is performed using the correlation window. The correct hypothesis is determined based on correlation results for the two hypotheses. The receiver timing is updated based on the hypothesized FAP and LAP for the correct hypothesis and used for demodulation.

Abstract: Techniques for detecting mode and guard length and estimating timing offset for an OFDM transmission are described. Multiple hypotheses for different combinations of mode and guard length that might have been used for the OFDM transmission are evaluated. For each hypothesis, correlation is performed on received samples for a hypothesized guard interval to obtain correlation results. The energy of the hypothesized guard interval is determined. A first metric is derived based on the correlation results and the energy. The first metric may be filtered, e.g., averaged. Noise is estimated, e.g., based on a set of elements for the filtered first metric at locations determined by an estimated timing offset for the hypothesis. A second metric is derived based on the filtered first metric and the estimated noise. The second metric for all hypotheses may be used to determine the mode, guard length, and timing offset for the OFDM transmission.

Abstract: Techniques for operating two receivers to receive data and paging from two systems are described. A primary receiver is associated with better performance than a secondary receiver under poor RF conditions. The two receivers may be operated in either a hybrid mode in which the primary receiver is used to receive paging or a simultaneous mode in which the second receiver is used to receive paging. One of the modes may be selected for use based on RF conditions, received power, demodulation metrics, and/or other criteria. In one design, a mode is selected based on the received power and one or more thresholds. In another design, the hybrid mode is selected for poor RF conditions and, for good RF conditions, the hybrid or simultaneous mode is selected based on received power.

Abstract: A system and method for detecting discontinuous transmission (DTX) frames. The inventive method includes the steps of receiving data transmitted in a plurality of frames; classifying each of the frames; analyzing the classification of a number of successive frames of the received data and providing a metric with respect thereto; and determining, in response to the metric, if a frame is a discontinuous frame. In the illustrative embodiment, the step of classifying includes the step of error checking the frames using a cyclic redundancy check (CRC) error checking protocol. The received frames are classified as good frames (G), erasure frames (E), or discontinuous frames (D). A numerical value is assigned to each of the frames based on the classification thereof. Next, the frames are filtered to provide an output Yn=Yn?1+Xn where ‘n’ is a frame number, Yn is the filter output for a given frame n, Yn?1 is the filter output for a previous frame, and Xn is a stream of input frames.

Abstract: A system and method for adjusting loop bandwidth in a synchronization loop of a radio receiver uses a noncoherent peak detector to determine the maximum magnitude and timing of incoming data at various code phase offsets. The maximum magnitude and timing are used in subsequent processing with the maximum magnitude value used to determine an adjustment factor. The timing information associated with the maximum signal value is used to despread the incoming signal. The despread incoming signal is subsequently scaled in accordance with the determined adjustment factor such that the input to the synchronization loop is scaled to produce the desired loop bandwidth.

Abstract: A method for localizing a mobile station, which in one embodiment is characterized by logging one or more wireless channels which belong to one or more network providers other than the mobile station's home network provider and which substantially currently provide communication with one or more discernable base stations; and establishing a geographic position of the mobile station by use of the one or more wireless channels which belong to the one or more network providers other than the mobile station's home network provider. In one or more various embodiments, related systems include but are not limited to circuitry and/or programming for effecting the foregoing-referenced method embodiment, the circuitry and/or programming can be virtually any combination of hardware, software, and/or firmware configured to effect to foregoing-referenced method embodiment depending upon the design choices of the system designer.