Abstract: Certain aspects of the present disclosure generally relate to methods and apparatus for performing random access channel (RACH) procedures with a base station. For example, certain aspects provide methods and apparatus for performing RACH procedures when a user equipment moves out of range from the base station (e.g., for RACH procedure success). One method includes attempting a RACH procedure with a first base station, determining the UE is out of range from the first base station for RACH procedure success, and, upon determining the UE is out of range from the first base station for RACH procedure success, reattempting the RACH procedure with the first base station or a second base station.

Abstract: Providing for reduced complexity or improved accuracy in de-mapping received wireless data streams for multi-channel wireless communication is described herein. By way of example, a low-complexity likelihood algorithm can be employed to de-map data bits from the wireless data streams. In one particular example, the likelihood algorithm can approximate a received bit with a subset of received wireless symbols correlated the bit, reducing algorithm complexity. In other examples, a limited set of received wireless symbols can be employed for the subset, further reducing algorithm complexity. According to at least one other example, logarithmic terms of the algorithm can be approximated with non-logarithmic functions, such as a look-up table, series expansion, polynomial approximation, or the like. These approximations can enhance symbol de-mapping accuracy while maintaining or improving processing overhead for a wireless receiver.

Abstract: A method and apparatus for channel estimation in wireless communications are provided. After an initial channel estimation and an estimation of the effective channel length (ECL) are performed, a weighting based on the ECL may be applied in an effort to remove noise from the initial channel estimate and provide an estimated channel with increased accuracy. Different weightings may apply for different channel lengths. A threshold may be used during the ECL estimation, and the threshold may be predetermined or calculated in an effort to adapt to different channel environments.

Abstract: This application provides techniques for robust handover to a target base station, based on performing initial ranging with the target base station. The techniques might generally include scanning neighboring base stations (BSs), selecting a target BS for a handover at least based on results of the scanning, performing initial ranging with the target BS, and sending a Handover Request to the target BS.

Abstract: A method and apparatus for decoding of tailbiting convolutional codes (TBCC) are disclosed. The proposed modified maximum-likelihood TBCC decoding technique preserves error correction performance of optimal maximum-likelihood based TBCC decoding, while the computational complexity is substantially decreased since a reduced number of decoding states has been evaluated. Compare to other sub-optimal TBCC decoding algorithms, modified maximum-likelihood TBCC decoding achieves improved packet error rate performance with similar computational complexity.

Abstract: Certain embodiments of the present disclosure provide a method for supporting multicast and broadcast services (MBS) with multiple-input multiple-output (MIMO) capabilities. This can be achieved by adding specific MIMO information into existing MBS-MAP messages while providing backward compatibility.

Abstract: Certain embodiments of the present disclosure provide a hybrid receiver diversity scheme that involves combining received signals in accordance with a combination of multiple receive diversity schemes. Certain embodiments of the present disclosure provide a hybrid transmit diversity scheme that involves transmitting diversity signals to a receiver according to a transmit diversity scheme selected based on signal quality measurements received from the receiver.

Abstract: A method for using a joint decoding engine in a wireless device is disclosed. A first symbol stream and a second symbol stream in a received multiple input multiple output (MIMO) signal is determined. A scaled channel estimate for a wireless transmission channel and a scaled noise covariance of the MIMO signal are also determined. The scaled channel estimate and the first symbol stream are whitened. Max log maximum a posteriori (MLM) processing is performed on the whitened first symbol stream to produce a first data stream. The first data stream may be de-rate matched and decoded to produce a decoded first data stream.

Abstract: Certain embodiments utilize raw signals to estimate channel quality, as contrasted to utilizing equalized signals or after channel estimation. For example, signal quality may be estimated by calculating powers of pilot sub-carriers and null sub-carriers of the raw signals. To mitigate channel effect, certain embodiments utilize first and/or second order differentiation schemes.

Abstract: A method for combining signals coming from multiple diversity sources may include performing maximal-ratio combining (MRC) based equalization and combining for receiver antenna diversity. The method may also include performing MRC-based equalization and combining for repetition diversity. The method may also include performing MRC-based equalization and combining for duplication diversity. The MRC-based equalization and combining for receiver antenna diversity, the MRC-based equalization and combining for repetition diversity, and the MRC-based equalization and combining for duplication diversity may each be performed separately.

Abstract: A method, an apparatus, and a computer program product for a wireless communication device are provided. The apparatus determines a receive timing for receiving through at least one receive chain element. The apparatus determines a time to turn on/off at least one transmit chain element based on the determined receive timing and based on receiver impact to the at least one receive chain element caused by turning on/off the at least one transmit chain element. The apparatus reduces receiver impact to the at least one receive chain element by turning on/off the at least one transmit chain element at the determined time.

Abstract: In accordance with a method for diversity combining in an orthogonal frequency division multiple access (OFDMA) system, repetition diversity equalization and combining may be performed with respect to received OFDMA signals. In addition, receiver antenna diversity equalization and combining may be performed with respect to the received OFDMA signals. The repetition diversity equalization and combining and the receiver antenna diversity equalization and combining may be performed in accordance with a maximum ratio combining (MRC) scheme.

Abstract: A synchronization and detection method in a wireless device may include performing coarse detection and synchronization with respect to a received signal. The synchronization and detection method may also include performing fine detection and synchronization for acquisition of the received signal. Results of the coarse detection and synchronization may be used for the fine detection and synchronization. The synchronization and detection method may also include performing tracking mode processing when the acquisition of the received signal has been achieved.

Abstract: In accordance with a method for identifying a preamble sequence and for estimating an integer carrier frequency offset, a signal that comprises a preamble sequence from a set of possible preamble sequences is received. A reduced set of integer carrier frequency offset (CFO) candidates may be determined. Cross-correlation operations may be performed with respect to the received signal and multiple candidate transmitted signals. Each candidate transmitted signal may include one of the set of possible preamble sequences. In addition, each candidate transmitted signal may correspond to one of the reduced set of integer CFO candidates. Multiple correlation values may be determined as a result of the cross-correlation operations. The correlation values may be used to identify the preamble sequence and to estimate the integer CFO.

Abstract: Certain aspects of the present disclosure relate to a method for iterative decoding with re-transmissions of data and to a method for iterative decoding with soft decision directed channel estimation.

Abstract: Certain embodiments of the present disclosure provide a method and an apparatus for peak-to-average power ratio (PAPR) reduction of a transmission signal in a single carrier frequency division multiple access (SC-FDMA) system. The method may utilize a permutation of a time domain signal, and/or a permutation of a frequency domain signal or a permutation of a signal transformed by a unitary matrix. The apparatus may include an M-point DFT or some other M×M unitary matrix, N-point IDFT, interpolation and frequency conversion units, and a pair of possibly different permutation matrices of size M×M, where M can be less or equal than N.

Abstract: Certain embodiments of the present disclosure allow a receiver to utilize both a minimum mean square error (MMSE) detection algorithm and a maximum likelihood (ML) detection algorithm. The receiver may control, based on various conditions, a mode selection signal to select between output generated with the MMSE detection algorithm and the ML detection algorithm. By sharing logical components, certain embodiments may allow a receiver to implement both ML and MMSE detection algorithms with minimal computational overhead when compared to implementing a single one of the decoding algorithms.

Abstract: Methods and apparatus for initially decoding a frame control header (FCH) in an orthogonal frequency-division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA) system in an effort to accurately determine the downlink frame prefix (DLFP) such that the remainder of an OFDM/A frame may be properly decoded are provided. Used, for example, when boosting factors applied in the transmitter to various elements of the OFDM/A frame and/or available pilots for the FCH are unknown, such methods may utilize a preamble channel estimate, the FCH pilots, or a combination thereof.

Abstract: An embodiment of the present invention is a technique to process signals in a communication system. A channel impulse response (CIR) generator generates a time-domain windowed CIR from a received signal using a window function. A thresholder thresholds the time-domain windowed CIR. A compensator compensates window effect for the thresholded time-domain windowed CIR to provide an enhanced channel estimate in frequency domain.

Abstract: The present disclosure includes techniques to process signals in a communication system, in which multiple signal processing units process signals received from multiple antennae. The signal processor units are controlled by operational-mode control signals, which are generated using an estimated Carrier-to-Interference-Noise-Ratio (CINR). The estimated CINR is generated using an equalized and combined signal, which is generated from the received signals and the estimated channel responses using the processed signals according to an operational mode. In another embodiment, a controller generates sub-carrier allocation signals using an allocation base. A channel status information (CSI) and multiple-input-multiple-output (MIMO) controller generates sub-carrier CSI signals and operational-mode control signals using the sub-carrier allocation signals, estimated channel responses, and estimated CINR. The operational-mode control signals select one of multiple antenna paths.