Abstract: In an embodiment, a transmitter includes first and second processing blocks, which may each include hardware, software, or a combination of hardware and software. The first processing block is operable to generate a first peak-reducing vector. And the a second first processing block is operable to receive a first data vector, the data vector comprising a plurality of samples, the first data vector having a first peak with a first index and a first magnitude, a second peak with a second index and a second magnitude that is less than the first magnitude, and a first peak-to-average power ratio, and to generate a second data vector having a second peak-to-average power ratio that is lower than the first peak-to-average power ratio by using the first peak-reducing vector.
Abstract: A mobile device includes a communications protocol stack including a MAC layer and TCP layer separated by an IP layer. A cross-layer coordination module parallel to the communications protocol stack is coupled to both the MAC layer and TCP layer. The MAC layer generates a message sent to the cross-layer coordination module indicating that the mobile device is about to engage in a communications handover from a first base station to a second base station. The cross-layer coordination module passes handover information to the TCP layer so as to inform the TCP layer of the communications handover. If the mobile device is operating as a TCP sender, the TCP layer freezes its connection and state during the communications handover. If the mobile device is operating as a TCP receiver, the TCP layer sends a TCP ACK message to a TCP sender having an advertised window size set to a zero value so as to cause the TCP sender to freeze a connection and state during communications handover.
Abstract: A method for decoding tail-biting convolutional codes. The method includes initializing a correction depth, selecting a first starting state from a set of encoding states, and initializing a metric value for the selected starting state as zero and the other states as infinity. The input bit stream is read and a Search Depth Viterbi algorithm (SDVA) is performed to determine path metrics and identify a minimum-metric path. The ending state for the minimum-metric path is determined and the output for this ending state is identified as “previous output.” A second starting state is set to the ending state of the minimum-metric path, and symbols equal to the correction depth from the previous output are read. The SDVA is performed on the second set of read symbols to generate a corrected output. A decoded output is generated by replacing symbols at the beginning of the previous output with the corrected output.
Abstract: A blind carrier frequency offset estimator is based on a single-OFDM-symbol training sequence in multi-user OFDMA uplink. Through multiple access interference modeling and analysis, a virtual user is employed that occupies the all null sub-carriers. By minimizing the energy leakage on the virtual user in term of tentative frequency offsets, the estimator can approach the real frequency offset. The estimator performs only on frequency-domain, simplifies interference calculations, and lowers the rank of the matrix. An iterative computation method is used to approach the real frequency offset.
Abstract: Embodiments of a processor architecture efficiently implement shadow registers in hardware. A register system in a processor includes a set of physical data registers coupled to register renaming logic. The register renaming logic stores data in and retrieves data from the set of physical registers when the processor is in a first processor state. The register renaming logic identifies ones of the set of physical registers that have a first operational state as a first group of registers and identifies the remaining ones of the set of physical registers as a second group of registers in response to an indication that the processor is to enter a second processor state from the first processor state. The register renaming logic stores data in and retrieves data from the second group of registers but not the first group of registers when the processor is in the second processor state.
Abstract: Embodiments of a processor architecture utilizing multi-bank implementation of physical register mapping table are provided. A register renaming system to correlate architectural registers to physical registers includes a physical register mapping table and a renaming logic. The physical register mapping table has a plurality of entries each indicative of a state of a respective physical register. The mapping table has a plurality of non-overlapping sections each of which having respective entries of the mapping table. The renaming logic is coupled to search a number of the sections of the mapping table in parallel to identify entries that indicate the respective physical registers have a first state. The renaming logic selectively correlates each of a plurality of architectural registers to a respective physical register identified as being in the first state. Methods of utilizing the multi-bank implementation of physical register mapping table are also provided.
Abstract: A system for recovering an architecture register mapping table (ARMT). The system includes a first number of collection circuits and decode circuits, a second number of selection circuits, and an enable circuit. Information related to the mapping between each physical register and an appropriate architecture register is obtained from a physical register mapping table (PRMT) by one and only one collection circuit during only one of a fourth number of instruction cycles. Each decode circuit has its input coupled to the output of one different collection circuit and is capable of converting its input into a third number bit wide binary string selection code at its output. Each selection circuit is configured to receive from each selection code a bit from a bit position associated with that selection circuit. The enable circuit is configured to appropriately enable mapping of information from the PRMT to the ARMT.
Abstract: Some microprocessors check branch prediction information in a branch history table and/or a branch target buffer. To check for branch prediction information, a microprocessor can identify which instructions are control flow instructions and which instructions are non control flow instructions. To reduce power consumption in the branch history table and/or branch target buffer, the branch history table and/or branch target buffer can check for branch prediction information corresponding to the control flow instructions and not the non control flow instructions.
Abstract: A comparison circuit can reduce the amount of power consumed when searching a load queue or a store queue of a microprocessor. Some embodiments of the comparison circuit use a comparison unit that performs an initial comparison of addresses using a subset of the address bits. If the initial comparison results in a match, a second comparison unit can be enabled to compare another subset of the address bits.
Abstract: A database stores updated information concerning protected communications services. A base station for a coexisting, and potentially co-channel, non-protected communications service makes an inquiry of the database requesting an identification of geographically relevant protected services along with the database stored information pertinent to each of those identified protected services. The returned information is processed by the base station to determine what channels are available for use by the non-protected service. An available channel is identified by the base station as the working channel for the non-protected service and the base station initiates a process to establish a communications network using the non-protected service and the selected working channel.
Abstract: Training sequence interference in an equalizer-based receiver in a time-division duplex (TDD) communication system can be avoided without using interference cancellation, by providing to the equalizer both the desired data portion of the received signal, and a portion of the training sequence that is adjacent the desired data portion and has a length commensurate with the delay spread associated with the training sequence interference. The portion of the equalizer output that corresponds to the adjacent training sequence portion can be discarded while retaining the desired equalized data.
Abstract: A blind carrier frequency offset estimator is based on a single-OFDM-symbol training sequence in multi-user OFDMA uplink. Through multiple access interference modeling and analysis, a virtual user is employed that occupies the all null sub-carriers. By minimizing the energy leakage on the virtual user in term of tentative frequency offsets, the estimator can approach the real frequency offset. The estimator performs only on frequency-domain, simplifies interference calculations, and lowers the rank of the matrix. An iterative computation method is used to approach the real frequency offset.