Abstract: Disclosed are apparatus and methods for use in a USB device with multiple processors, allowing shared USB connectivity in the device. The disclosed apparatus and methods allow selective coupling of a first processor to a USB port of the device or to a USB hub operable to route a plurality of USB connections including connection of a second processor to the port. Providing selective coupling of the processors to the port by switching the coupling of the first processor and selectively powering the hub on and off for selective coupling of the second processor, thereby selectively enabling tethered networking such as wireless networking, affords increased power savings in the device. Furthermore, default coupling of the first processor to the port allows for USB battery charger detection, or direct connectivity to USB peripheral devices, as well as providing programming capability via the default coupling of the port to the first processor.

Abstract: An apparatus and method for area and speed efficient fast Fourier transform (FFT) processing comprising mapping a one-dimensional DFT to a multi-dimensional representation; re-indexing the multi-dimensional representation as a radix 23 decimation architecture; simplifying the radix 23 decimation architecture to obtain a nested butterfly architecture; acquiring N samples of a finite duration time-sampled signal; and inputting the acquired N samples into the nested butterfly architecture to obtain a N-point fast Fourier transform (FFT) output.

Abstract: Methods and apparatus which reduce or completely eliminate non-shift based divisions as part of estimating transmitted symbols and/or generating slicing parameters corresponding to two symbol transmission streams in a wireless communication system are described. A linear least squares error estimation filtering module performs symbol estimations and/or slicing parameter generation while avoiding non-shift based division operations. The linear least squares estimation module generates intermediate parameters, and implements equations which facilitate symbol estimation utilizing shift based divisions while avoiding non-shift based divisions.

Abstract: Techniques to perform channel estimation with pilot weighting are described. A receiver receives at least one transmission symbol for a pilot transmitted by a transmitter. Each transmission symbol may be generated with a single-carrier multiplexing scheme (e.g., IFDMA or LFDMA) or a multi-carrier multiplexing scheme (e.g., OFDMA). The receiver processes each received transmission symbol and obtains received pilot values. The receiver may derive an interference estimate based on the received pilot values and may estimate the reliability of the received pilot values based on the interference estimate. The receiver determines weights for the received pilot values based on the transmitted pilot values, the estimated reliability of the received pilot values, and/or other information. The receiver derives a channel estimate based on the received pilot values and the weights. The receiver then performs data detection (e.g., equalization) on received data values with the channel estimate.

Abstract: A time averaging filter for channel estimation is described. Different time averaging is used for different taps or tones of a communication system. Two methods are suggested for determining the time-averaging filter for channel estimation for the communication systems without prior knowledge of SNR, channel Doppler and fading statistics. The first method includes a bank of different filters, each tuned for optimality in a certain range of SNR and Doppler. For each tone in the frequency domain (or tap in the time domain), the first method selects a filter among the set of filters that minimizes a certain computed metric. The second method directly computes, at each tone (or tap), the “best” filter in a least-squares sense, using empirically determined second-order statistics.

Abstract: In a single-carrier frequency division multiple access (SC-FDMA) system, a receiver receives transmission symbols from a transmitter, determines a set of subbands used by the transmitter, processes the received transmission symbols for the set of subbands, obtains received pilot values for a transmitted pilot, and obtains received data values for transmitted data. The receiver may iteratively perform channel and interference estimation for the transmitter. The receiver selects an initial interference estimate, derives a channel estimate based on the received pilot values and the interference estimate, and derives a new interference estimate based on the received pilot values and the channel estimate. The receiver may repeat the derivation of the channel estimate and the interference estimate for multiple iterations. The receiver then performs data detection and/or receiver spatial processing on the received data values based on the channel estimate and the interference estimate.

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: Methods and apparatus for providing monitoring of voice quality and diagnostic data related to voice quality on a wireless device. Monitoring thresholds can be implemented that allow for additional precautionary measures and/or further monitoring to occur if a threshold level of voice quality performance is experienced. The results of the voice and diagnostic monitoring can be communicated to the service provider who can then collect, analyze and generate reports to assess and determine quality-related problems experienced by the communication network.

Abstract: Methods and apparatus for avoiding overflow and underflow conditions through the determination of appropriate scaling factors in signal estimation processing in a receiver are described. The receiver estimates transmitted symbols from one or more transmitter device antennas, while avoiding underflow and overflow conditions. A pilot based noise estimate and an estimated expected received signal power, corresponding to a transmit antenna, are used to generate an SNR corresponding to the transmit antenna. The generated SNR is used to determine, e.g., select from a fixed size set of predetermined scale factor values, a scale factor to be used for estimation processing associated with the transmit antenna. In some embodiments, the generated scaling factors are used by a fixed point processing linear least squares error estimation module. Scaling factor determination is performed at a rate which is slower than the rate at which symbols are received from a transmit antenna.

Abstract: A method for adaptive Bluetooth low power wake up and discovery is provided whereby wake-up triggers are uploaded to Media Access Control (MAC) firmware. A data stream representing a trigger arrives as either an interpretable binary stream of instructions, or as a concatenation of events listed in a preset table. Various parameters allowing flexible wake-up triggering, such as Service Set Identifiers (SSIDs) to scan for probability likelihoods, are also uploaded. Both table-based and interpretable instructions are designed to ensure the security of the trigger by limiting the functionality of the trigger to only trigger-related events (e.g., scanning, pre-reserved memory). Both the table and the instruction set are designed in a minimalistic fashion to allow a slim and fast firmware-side implementation. Insignificant modifications to existing computer or Operating System (OS) architecture take advantage of the already existing MAC processor in many 802.11 interfaces, offering enormous flexibility.

Abstract: A method for detecting an access code in a receiver that does not require an explicit DC-offset interference correction block, comprising: a) projecting a received signal R onto a subspace orthogonal to the DC; b) projecting the access code Ci onto the subspace; and c) detecting the presence and location of the access code Ci and eliminating any DC offset therein when the frequency offset f0 in the access code Ci is orthogonal to the subspace, and is therefore nulled out.

Abstract: Techniques for efficiently decoding packets sent with H-ARQ are described. Packet decoding for H-ARQ may be performed based on local search around a start of packet (SOP) decision for a packet. The SOP decision for the packet may be made based on traffic detection results for received transmissions. At least one SOP hypothesis may be determined for the packet based on the SOP decision, and the received transmissions may be decoded based on the at least one SOP hypothesis. A sliding SOP window may be used to keep track of SOP hypotheses for the packet. The sliding window may be initialized at an earliest received transmission, moved forward for each subsequent received transmission with no detected packet data, and maintained at the first received transmission with detected traffic. Rotating buffers may be used to store received transmissions for packets for decoding.

Abstract: Pilots are transmitted on demand on a reverse link and used for channel estimation and data transmission on a forward link. A base station selects at least one terminal for on-demand pilot transmission on the reverse link. Each selected terminal is a candidate for receiving data transmission on the forward link. The base station assigns each selected terminal with a time-frequency allocation, which may be for a wideband pilot, a narrowband pilot, or some other type of pilot. The base station receives and processes on-demand pilot transmission from each selected terminal and derives a channel estimate for the terminal based on the received pilot transmission. The base station may schedule terminals for data transmission on the forward link based on the channel estimates for all selected terminals. The base station may also process data (e.g., perform beamforming or eigensteering) for transmission to each scheduled terminal based on its channel estimate.

Abstract: An apparatus and method for describing channel resources comprising allocating channel resources for a plurality of tiles; and determining a description of the channel resources allocated for a tile of the plurality of tiles by performing one or more of the following steps: a) comparing the size of the tile to a tile size threshold (THsize) to determine if the size of the tile is small or large; b) comparing the allocation of the channel resources to the tile to an allocation threshold (THallocation) to determine if the allocation of the channel resources is sparse or not sparse; and c) determining if the allocation of the channel resources within the tile is regularly spaced or not regularly spaced.

Abstract: Systems and techniques for secured communications from a subscriber station is disclosed. The subscriber station includes a processor having an authentication algorithm for a first network. The processor is configured to use a key for a second network in the authentication algorithm to establish a session with the second network.

Abstract: Methods and apparatus for initial acquisition gain control in a communication system a method for use in a wireless communication system are disclosed. A disclosed methodology includes measuring the power of a signal received by a transceiver a number of times over a prescribed time period, the signal including a number of symbols. A gain of the transceiver is unidirectionally adjusted when a currently measured power is greater than a previously measured power during the prescribed time period until a maximal power level is measured. By adjusting the gain to accommodate a maximal power value, which is the same as the power level of an acquisition pilot symbol, overshoot and distortion by the transceiver are avoided during initial timing and frequency acquisition. Corresponding apparatus are also disclosed.

Abstract: Systems and methods are provided for processing Time Domain Multiplexing Pilot symbols by employing complex accumulators to determine peak values which indicate the start of timing and frequency information. In an embodiment, a method is provided for timing acquisition in a wireless network. The method includes acquiring samples from an Orthogonal Frequency Division Multiplexing (OFDM) data packet over a predetermined period of time, where the samples include one or more TDM pilot symbols. The samples are then processed to determine a maximum value that indicates the TDM pilot symbol has been detected.

Abstract: A multiple-input receiver for processing one or more communication signals is disclosed. The receiver includes a first and second demodulators, a decoder and decision logic. The first and second demodulators respectively use a first algorithm and a second algorithm and are both coupled to the receiver. The first algorithm includes interference nulling and is different from the second algorithm. A decoder can be alternatively used with the first or second demodulators to decode one or more signals from the receiver. The decoder produces a decoded signal. The decision logic chooses to use either the first demodulator or the second demodulator to affect the decoded signal.

Abstract: An apparatus and method for synchronizing RF activities comprising receiving a notification relating to transmission activities; determining at least one of a plurality of RF modules to relay the notification; and relaying the notification to at least one of the plurality of RF modules.

Abstract: Apparatus and methods for managing predetermined malfunction events in a wireless device operating in a wireless communications network. Malfunction event data and operational data are recorded by the wireless device based on a selected malfunction event tracking configuration. Further, a recovery module associated with the wireless device operates to attempt to recover information leading up to and including the malfunction event. The collected information may be transmitted to a user manager in the form of a malfunction event log. The malfunction event log may be analyzed to characterize the malfunction, and is particularly useful for determining the sequence and identity of events leading to the malfunction, including a crash, freeze and reset.