Abstract: System and method for detecting symbols wherein there may be a large frequency error. A preferred embodiment includes receiving an estimated frequency error, calculating a vector based on the estimated frequency error, buffering symbols from two symbol streams, rotating the symbols from the two symbol streams using the vector, estimating a channel gain for the symbols in the second symbol stream, and applying the channel gain to the rotated symbols from the second symbol stream.

Abstract: Search scheduling circuitry for use with a wireless communication device, such as a mobile telephone, includes a search time calculator, a search period calculator, a queue circuit, and a search time circuit. The search scheduler generates a prioritized list of cells to be adaptively searched in response to the network requirements and the capability of the search hardware. If there are very few “handoff” possibilities the search hardware may be turned off and then back on in time to meet the search rate requirements. However, if there is an excessive number of possibilities, the searcher list is prioritized and pared to assure the most likely candidates are searched. This search scheduling minimizes battery power consumption while meeting the search rate requirement and maximizes use of the search hardware for measuring signal quality from multiple neighboring cells and estimating the delay profile of active cells.

Abstract: Gain and phase imbalance is estimated by using an IQ-swapped spreading sequence in addition to a regular spread pilot signal. The IQ-swapped spreading sequence is the spreading sequence whose real and imaginary components are the imaginary and real components of the regular spreading sequence. The gain imbalance can be estimated by a function of the difference between the real component of a regular despread pilot signal and the imaginary component of the IQ-swapped pilot signal. In a similar fashion, the phase imbalance is estimated by a function of the difference between the imaginary component of a regular despread pilot signal and the real component of the IQ-swapped despread pilot signal. A controller such as a DSP (102) uses the gain and phase imbalance estimates to control a gain and phase correction circuit (104). In one embodiment, the correction circuit (104) includes a plurality of multipliers (202–212) and a ROM look-up-table (202) in order to perform the imbalance correction.

Abstract: System and method for providing additional channels to an existing communications system. A preferred embodiment comprises a coprocessor (such as coprocessor 215) coupled to a modem (such as modem 205), wherein transmissions from the modem are routed to the coprocessor. The coprocessor then can insert transmissions that use the additional channels into the transmission from the modem. Timing consistency can be ensured by the coprocessor using scrambling and channelization codes that are provided by the modem. The use of the coprocessor can allow the use of an existing design for the modem rather than creating a new design when a revision to a technical standard is released, saving time and money for equipment manufacturers.

Abstract: System and method for improving the detection performance of a wirelessly transmitted signal. A preferred embodiment comprises specifying a desired response for missed channel detection and false alarm probabilities for a plurality of signal qualities and determining if a channel detection threshold is based on missed channel detection or false alarm probabilities for the plurality of signal qualities. A signal quality estimate of a channel can be inferred from a signal quality measurement of a second channel, wherein the channel and the second channel are sourced by a single transmitter. The channel detection threshold can be adjusted based upon the previously determined required response and the signal quality estimate of the channel.

Abstract: A method and apparatus for processing modulation symbols for soft input decoders using an efficient method of calculating an accurate log-likelihood ratio without relying on approximations is described. In contrast to other techniques that calculate distance metrics based on the individual constellation points, the method of the invention analyzes distances based on different groupings of points, where a given group (e.g., one of the II+k or II?k sets) is defined by the same bit (1 or 0) in the same bit position. A recursive scheme is preferably used where previous computations are saved and used for subsequent computations or iterations and the decoupled processing of real and imaginary components associated with the I and Q components.

Abstract: System and method for managing finger and path resources. A preferred embodiment comprises receiving a delay profile, processing paths from the delay profile, placing the processed paths into a plurality of sets based on path criteria, and assigning the placed processed paths to demodulating fingers. A preferred embodiment further comprises the use of historical information on paths in the placing.

Abstract: System and method for code acquisition in a wireless communications system with a delay lock loop. A preferred embodiment comprises assigning a delay lock loop (DLL) to each path in a received signal with multipath, adjusting each DLL to maximize sample strength, grouping samples that are less than a first threshold apart into groups, adjusting DLL timing of samples in groups, regrouping groups that are less than a second threshold apart, applying a group decision to regrouped groups, and repeating the regrouping and applying until all groups are greater than the second threshold apart.

Abstract: System and method for detecting symbols wherein there may be a large frequency error. A preferred embodiment comprises receiving an estimated frequency error, calculating a vector based on the estimated frequency error, buffering symbols from two symbol streams, rotating the symbols from the two symbol streams using the vector, estimating a channel gain for the symbols in the second symbol stream, and applying the channel gain to the rotated symbols from the second symbol stream.

Abstract: A method of symbol combining and incremental redundancy for link adaptation and code space management was proposed. In order to reduce constraints on the Walsh codes allocation, MCS level change, as well as frame duration change for the initial transmission and re-transmissions, a “rate matching” stage is proposed between the Turbo encoder and block interleaver on the transmitter. In the initial transmission, the Turbo encoded symbols are interleaved with or without any puncturing or repeating (i.e. puncture/repeat factor is set to 1). The coded symbols are also stored in the memory for possible retransmissions. In the re-transmission, the transmitter first determines the number of Walsh codes available for this user and MCS level and frame duration according to the C/I feedback values from MS. The stored coded symbols are then punctured or repeated according to “rate matching factors”.

Abstract: A method is provided to decode data encoded by any block code in a manner that substantially improves the error correction capability of the block codes, and that is independent of the encoder. The structure associated with the method desirably allows the testing of those hypotheses that are known to exist, such that one can use the a priori knowledge of the possible set of hypotheses to only search from among them. The method of decoding data is both advantageous and desirable since knowing the subset of the code word space that is being utilized in essence allows the distance between the code words to be increased yielding significant decoding benefits.

Abstract: This disclosure is generally directed to communication systems, devices used in communication systems and associated methods which may implement parallel hypothesis search techniques. The disclosed parallel hypothesis search techniques may permit a hypothesis to be dismissed early (i.e., before hypotheses in other searchers have completed their evaluation). Early hypothesis dismissal permits a new hypothesis to be loaded into the searcher while other searchers advantageously continue to evaluate their hypotheses.

Abstract: System and method for intelligently and efficiently processing the results of searches for signals in a direct sequence spread spectrum communications system. A preferred embodiment comprises a search engine (for example, search engine 405) and a hardware result processor (for example, result processor 410) with a memory (for example, memory 415) as an interface. The search engine may perform multiple correlations of a pilot channel and then writes the correlation results exceeding a specified threshold to the memory. The result processor reads the correlation results from the memory and performs result filtering and builds a list of maximum value correlation results. The result processor and the search engine functions with independence from one another therefore, there is therefore, little wasted overhead where one has to wait for the other. The result filtering also makes it simpler to combine signal multipaths and simplifies pilot channel strength comparisons.

Abstract: System and method for decoding punctured subframes. A preferred embodiment comprises a first deinterleaver unit (for example, 5-ms deinterleaver 502) and a second deinterleaver unit (for example, 20-ms deinterleaver 504) operating in parallel, deinterleaving one symbol stream using 5- and 20-ms duration frame formats, for example. After the reception of each 5-ms subframe, the subframe is decoded in a decode unit (for example, rate matching, decoding, and CRC checking (RDC) unit 530) to verify that the subframe contains 5 ms duration frame data. If so, the subframe is noted. If all 5-ms subframes in a 20-ms duration frame contain 5-ms duration data, no decoding of results by the second deinterleaver unit is needed. If the entire 20-ms duration frame is not all 5-ms duration data, then the 5-ms duration data subframes are zeroed and the remaining data is decoded as 20-ms duration data.

Abstract: A method and apparatus adaptively scales the decoder input for a low-cost user equipment (UE) to reduce the memory requirement without degrading decoder performance. In order to optimize the decoder performance for a small number of input bits, the method estimates the interference of the inner receiver output and scales the decoder input such that its variance is kept constant. The method further estimates the interference of the Pilot channel and translates it into the interference of the data channel in order to avoid the estimation bias problem in a noisy channel. The method then uses a difference value of the phase-corrected pilot symbol to solve the fading rate dependency problem of the sample mean method. For a Rake receiver, the method sums up the interference estimated from each finger. For a multi-antenna receiver, the method sums up the interference estimated from each antenna demodulating element.

Abstract: A reconfigurable chip level equalizer having circuitry that restores signal orthogonality and eliminates channel interference for a wireless transmitted signal. In at least some embodiments, the reconfigurable chip level equalizer comprises two or more adaptive equalizers, a plurality of operational blocks that interconnect the two or more adaptive equalizers, and a control mechanism that configures the two or more adaptive equalizers and operational blocks according to different signal delay profiles.

Abstract: A method for managing multipath signals to be demodulated by a receiver with multiple demodulators. The method includes a series of steps, including receiving the multipath signals at a wireless communication receiver device, finding the multipath signals having sufficient signal strength for demodulation, and measuring an arrival time of one of the multipath signals. In one embodiment, the present invention also recites measuring a signal-to-noise ratio (SNR) level of one of the multipath signals, updating a multipath list with the arrival time and the signal-to-noise ratio if the multipath signal is identified based upon the arrival time with one of the multipath signals existing in the multipath list, and identifying newly-found multipath signals and evaluating one of the newly-found multipath signals based on the signal-to-noise ratio for categorization into one of a plurality of states.

Abstract: System and method for efficient detecting of direct sequence spread spectrum signals using a searcher with batched processing. A preferred embodiment comprises a controller (such as the MCU 310) that writes sets of search parameters to a memory (such as the memory 315) to specify a group of hypotheses. A searcher (such as the searcher 305) reads the sets of search parameters from the memory and generates the groups of hypotheses from the sets of search parameters. The searcher then assigns the hypotheses to correlators and tests each of the hypotheses. Results from the testing can be written back to the memory.

Abstract: System and method for using pipelined vector processing in the detection of direct sequence spread spectrum signals. A preferred embodiment comprises a memory (such as memory 507) used to store a plurality of hypotheses, a PN sequence generator (such as PN generator 527) that can generate PN sequences for each of the hypotheses, and vector processing correlators and accumulators (both coherent and non-coherent). The PN sequence generator can arbitrarily generate PN sequences for any hypothesis, permitting the simultaneous testing of multiple hypotheses. A searcher controller (such as search control unit 319) can schedule access to different units in a pipelined fashion to increase the number of hypotheses tested in a given period of time.

Abstract: System and method for performing symbol boundary aligned searches of signals. A preferred embodiment comprises a search control unit (such as search control unit 725) that can determine a start and stop condition for a correlation based on a hypothesis, a searcher (such as searcher 705) which includes a multiplexer that can select a subset of samples of a received sequence based on the hypothesis and start and stop conditions. The search control unit can then wait for the occurrence of the start condition and assign the hypothesis to a correlator, which will correlate the subset of samples with a locally generated pseudo-random number sequence based upon the hypothesis.