Abstract: In a mobile wireless communication system a client terminal needs to continuously maintain its receive and transmit operations in time alignment with the serving base station timing. A client terminal may initially achieve the timing alignment with the serving base station through the cell search procedure. Subsequently, as a client terminal may move toward or away from a serving base station, it may need to continuously track its timing to remain time aligned with the serving base station. In Orthogonal Frequency Division Multiplexing (OFDM) systems, one of the commonly used methods for time tracking may be the Cyclic Prefix (CP) correlation. When the length of the CP is small, the reliability of the CP correlation may be low, especially when the signal quality is poor. A method and apparatus are disclosed that use the initial synchronization signals for time tracking for improved performance and reduced complexity.

Abstract: Automatic Repeat Request (ARQ) protocol is used in many modern telecommunication systems for improved link level reliability. Hybrid ARQ (HARQ) protocol takes advantage of the retransmissions in ARQ to enable the receiver to decode the currently received data by combining it with all the previously received transmissions that were not successfully decoded. Each successive retransmission improves the probability of correctly decoding the data. To support HARQ, the receiver is required to store the previously received unsuccessful transmissions for combining with future retransmissions. The storage of the previously received unsuccessful transmissions can be very large depending on type of the HARQ protocol used. A method and apparatus are disclosed that enable reduced memory storage requirements while maintaining the HARQ performance requirements. The reduced memory requirements result in reduced cost, reduced power consumption and lowered cost.

Abstract: In data communication systems, data packet processing for transmission and reception may go through different stages such as segmentation or packing of the data packets on the transmission side and duplicate detection, reordering, and reassembly on the reception side. For reliable data transmission between the peers, acknowledgement based retransmission protocol known as Automatic Repeat Request may be used where each retransmission can further segment the previously transmitted data packets. This type of data processing may lead to high memory requirements and high processing requirements. A method and apparatus are disclosed that maintain additional information about the data packets which enables virtual segmentation and packing on the transmitter side and on the receiver side, virtual duplicate detection, reordering and reassembly.

Abstract: In some applications, such as randomization and cryptography, remainder computation for a number is required. The remainder computation is also used in modulo arithmetic. The remainder computation can be simplified when the divisor belongs to a certain class of numbers. A method and apparatus are disclosed that enable low complexity implementation of remainder computation of any number when the divisor belongs to a type of numbers that can be represented as 2k+1.

Abstract: Spatial Multiplexing (SM) with Multiple Input Multiple Output (MIMO) is used in many wireless communication systems for providing high data rate in a given channel bandwidth. When SM-MIMO is used for sharing the same resources for multiple users (MU-SM), the control information describing the parameters of MU-SM need to be sent separately to all the users that may be sharing the same resources. The base station in a wireless communication system may only provide the parameters required by each specific client terminal for decoding the data addressed to it. A method and apparatus are disclosed that enable improved decoding of MU-SM signals in scenarios where information about the parameters of other transmissions on the same resources or absence of any transmission other than the one intended for the subject client terminal is not available.

Abstract: Digital communications systems employ Forward Error Correction (FEC) for robustness against fading, noise and interference. FEC is designed to support different code rates to meet different requirements. Different code rates may be achieved by performing puncturing or repetition operation. At the receiver the decoding may be performed on the baseline code rate to enable common decoder module. To enable this capability, the input to the decoder of the error correcting code must be initialized to zeros for the bit positions corresponding to bits that are not transmitted. For high throughput systems, it is not efficient to initialize particular bit positions to zero. A method and apparatus are disclosed for joint Rate Matching and deinterleaving that enable the decoder to begin the decoding operation on the received bits without explicitly initializing the punctured bit positions to zero.

Abstract: Fast Fourier Transform (FFT) operates by decomposing a longer length input signal into many smaller length signals. The decomposition may be carried out in different number of smaller length signals at each stage. The number of smaller length signals at each stage is referred to as a radix. FFT may be implemented either with decimation in time or with decimation in frequency method. Depending on the method used, reordering of the input or the output data sequence may be required in order to get the data sequence in the correct order. Mixed radix FFT is an FFT structure that uses a combination of radixes. The reordering for mixed radix FFT by bit reversing or digit reversing the index has non-trivial complexity. A method and apparatus are disclosed that enable efficient and zero latency reordering of a data sequence for an FFT structure that uses a combination of two or more radixes.

Abstract: In data communication systems, data packet processing for transmission and reception may go through different stages such as segmentation or packing of the data packets on the transmission side and duplicate detection, reordering, and reassembly on the reception side. For reliable data transmission between peer entities, acknowledgement based retransmission protocol known as Automatic Repeat Request may be used where each retransmission can further segment previously transmitted data packets. This type of data processing may lead to high memory requirements and high processing requirements. A method and apparatus are disclosed that maintain additional information about the data packets which enables virtual segmentation and packing on the transmitter side and on the receiver side, virtual duplicate detection, reordering and reassembly.

Abstract: During cell search procedure in 3GPP LTE wireless communication system it is required to detect multiple cells which may be observable by a client terminal. In conventional cell detection a client terminal may detect false cells along with true cells. The number of false cells may depend on specific conventional detection algorithm used. A method and apparatus are disclosed that use of Differential Correlation based SINR metric for filtering out false cells from the list of detected cells reported by the conventional cell detection methods. The combination of conventional cell detection and Differential Correlation SINR based false cell filtering enables significant reduction in false cells reported to the network and reduces power consumption in a client terminal.

Abstract: In any cellular communication the network transmits broadcast information with some periodicity which is defined by the network parameters. The client terminal must acquire this system information in order to access the services from the network. The time required by the client terminal to acquire all the necessary system information to initiate network access may depend on the scheduling of the system information broadcast by the network. In some cases the scheduling information about the system information may be described in another system information message whose schedule may be fixed or known a priori. Conventional method of decoding the complete system information may involve decoding attempt for all the possible instances of transmission of the system information. A method and apparatus are disclosed that enables acquisition of the system information based on stored known instances of system information transmission. This results in reduced power consumption at the client terminal.

Abstract: In many wireless communication systems, there is a major problem with the coverage in indoor environments because of signal loss during signal penetration through walls and other structures. Femto cells or repeaters may be used to address the signal coverage issue for indoor environments. The cost of femto cells or repeaters may be high depending on its capabilities. Method and apparatus are disclosed for a Signal Enhancer with reduced complexity to enhance the signal for an OFDM based TDD wireless communication system. This may result in a lower cost solution for improving the coverage and the overall communication system performance.

Abstract: In order to support low latency and bursty internet data traffic, the 3GPP LTE wireless communication system uses dynamic allocation. To keep the allocation overhead lower, the system is designed such that the client terminal must perform a number of decoding attempts to detect resource allocations. During course of the decoding attempts a false resource allocation may be decoded by the client terminal. The false detection may lead to multiple issues for the performance efficiency of the client terminal and the overall communication system. A method and apparatus are disclosed than enable the detection of false resource allocation. This in turn improves the performance and efficiency of the client terminal and the wireless communication system.

Abstract: Modern mobile communication devices have a number of features that enable the users to stay connected with people in their contacts list. These mobile devices also keep users informed about various events such as email, text messages, etc. While these features are useful they can be intrusive or distracting under some conditions. To reduce disturbances and intrusions, various notifications that inform the user about the new events on the mobile device may be temporarily disabled. However, event notifications must be explicitly re-enabled by the user when it is free to receive the notifications. The user may forget to re-enable the event notification which may lead to missed calls, event notifications, etc. A method and apparatus are provided that disable and enable event notifications on mobile devices adaptively to allow the users to reduce the intrusiveness of the mobile device notification when not required while minimizing any missed event notifications.

Abstract: The power consumption in a client terminal is one of the important aspects of wireless communication systems. The power consumed when a client terminal is in standby mode when it is periodically monitoring the paging messages has a significant impact of the battery life. A method and apparatus are disclosed that enable reduction of the power consumption in standby mode and extend battery life of a client terminal.

Abstract: Low latency wireless communication applications require highly dynamic allocation of resources. Providing allocation information on a highly dynamic basis increases the overhead of control signaling for allocation. A technique known as blind PDCCH decoding is used to reduce the control signaling overhead for allocation information. However, blind decoding occasionally may lead to invalid detection of allocation messages which in turn may lead to a number of problems such as wasted bandwidth, more power consumption, reduced throughput, etc. A method and apparatus are disclosed that may detect the invalid allocation messages and discard them which in turn may lead to detection of valid allocation messages for increased data throughput and reduced power consumption and improve the overall performance.

Abstract: Uplink power control is an essential part of wireless communication systems. The transmit power control operation in the uplink of a wireless communication system is a combination of the algorithms used at the base station and the reception and processing of the power control commands at the client terminal. An important aspect for the effectiveness of transmit power control is the timeliness of the changes made to the uplink transmit power at the client terminal. Sometimes the transmit power control loop may take longer time to respond to real time dynamics and may lead to inferior performance. A method and apparatus are disclosed that enable the power control adjustments at the client terminal such that the uplink transmit power is within the specified limits of the wireless communication network and yet enhance the performance of the client terminal and the wireless communications network.

Abstract: In a wireless communication system, a client terminal may first establish time and frequency synchronization with the network. While establishing the time and frequency synchronization, a client terminal may need to detect additional parameters about the network, such as physical cell identity, before it can initiate communication with the wireless communication system. Detecting the network parameters in presence of time and frequency offsets increases the complexity of the initial cell search procedure that includes time and frequency synchronization as well as detection of network parameters. A method and apparatus are disclosed that achieve frequency synchronization using frequency domain cross-correlation earlier in the cell search procedure, which in turn reduces the complexity and improves the performance of the latter stages of cell search procedure and the overall performance of the client terminal.

Abstract: Wireless communication systems employ Multiple Input Multiple Output (MIMO) transmission and reception schemes to increase performance and the data rate of the system. A new approach for an SM-MIMO decoder that operates on the received symbols in parallel is presented. The new approach performs two different QR decompositions of the estimated channel matrix and produces two triangular matrices; one is right triangular and the other is left triangular. The modified systems of equations are processed in parallel. After each M-algorithm process has processed half of the total number of stages, total search space for the globally optimal transmitted symbol vector is reduced significantly. Finally, cumulative distance metrics are computed for the symbol sequences in the reduced search space and a global minimum is determined for the estimated transmitted symbol vector. This approach offers faster processing of the SM-MIMO signals and reduced distance metric computations and search operations.

Abstract: Estimating and compensating the frequency offset between a transmitter and a receiver is essential for reliable communication in wireless communication systems. Before a client terminal synchronizes with a base station, the initial frequency offset may be high. The frequency offset estimation may need to be performed even without having time synchronization with a base station. In case of cellular systems multiple base stations may be using the same RF channel to transmit their signals. The signals from different base stations may be superimposed at the receiver of the client terminal. A method and apparatus are disclosed for frequency offset estimation in presence of the signals from multiple base stations and with unknown timing of the base station.

Abstract: Adaptive Modulation and Coding Scheme (MCS) selection is used in many wireless communication systems. The goal of Adaptive MCS selection is to use the most suitable MCS for any particular channel conditions. Often, the MCS selection is based on channel measurements by the client terminal. The relationship between the block error rate (BLER) and the Signal-to-Interference-plus-Noise Ratio (SINR) is not linear. The BLER is often determined by the lowest SINR rather than the average SINR experienced by the set of bits that are part of the block. The Exponential Effective SINR Mapping (EESM) method is often used to compute effective SINR for adaptive MCS selection. However, the complexity of selecting the optimum channel feedback from the client terminal to the base station is typically high. A method and apparatus are disclosed that enable EESM for selecting the most suitable MCS with reduced complexity and reduced power consumption.