Abstract: A transmitter can include an encoder configured to encode a data sequence based on a first encoding rate to generate a first encoded bit stream having first bits with at least one first repeated bit and encode the data sequence based on a second, different encoding rate to generate a second encoded bit stream having second bits with at least one second repeated bit, where the first and second encoded bit streams each fully represent the data sequence. A receiver can include circuitry configured to produce identified repeated bits by identifying a repeated bit in the first encoded bit stream and a repeated bit in the second encoded bit stream that correspond to a same bit position, combine the first encoded bit stream and the second encoded bit stream including the identified repeated bits to generate a combined bit stream, and decode the combined bit stream.

Abstract: The invention relates to a device and a method for determining a symbol during reception of a signal coupled with a quadrature signal pair having a discriminator for the determination of a symbol with an analysis of a received signal in complex coordinate space, and a control loop for QAM frequency control and/or rotation control while control parameters are used, which are constructed and/or controlled depending on at least one of the symbols to be decided by the discriminator so that the control parameters are adjusted for decisions to be taken later, wherein one weighting device is constructed and/or controlled, providing in each case one weighting value for the symbols to be decided and/or decided by the discriminator among a plurality of weighting values depending on the symbol position in the complex coordinate space for the control loop.

Abstract: A system that incorporates teachings of the subject disclosure may include, for example, a method for scanning a radio frequency spectrum for an available frequency band, selecting an available frequency band in the radio frequency spectrum even if the available frequency band is affected by radio frequency interference, measuring a signal strength in portions of the available frequency band, correlating the signal strength of each portion to generate a correlation factor, detecting radio frequency interference in the available frequency band according to the correlation factor, and generating tuning coefficient data to cause the filter apparatus to substantially suppress the radio frequency interference in the available frequency band. Other embodiments are disclosed.

Abstract: The determination and identification of channels in a signal is an important aspect of the operation of a signal receiver. A method (800) is described including the steps receiving (802) a signal containing a plurality of channels, filtering (806) the signal to produce an indicator of a channel band edge, and determining (818) a characteristic of the channel based on the indicator. Additionally, an apparatus (300) is described including a spectrum shift circuit (304) that receives an input signal and shifts the frequency spectrum of the signal, a filter (306) that filters the frequency shifted signal to produce an indicator of a band edge of a channel, and a signal analysis circuit (316, 318) that determines a characteristic of the channel based on the indicator of the band edge, the signal analysis circuit (316, 318) controlling the frequency shift in the spectrum shift circuit (304) based on the determined characteristic of the channel.

Abstract: The present invention relates to a method for multiple-input multiple-output impairment pre-compensation comprising: receiving a multiple-input signal; generating a pre-distorted multiple-input signal from the received multiple-input signal; generating a multiple-output signal by feeding the pre-distorted multiple-input signal into a multiple-input and multiple-output transmitter; estimating impairments generated by the multiple-input and multiple-output transmitter; and adjusting the pre-distorted multiple-input signal to compensate for the estimated impairments. The present invention also relates to a pre-compensator for use with a multiple-input and multiple-output transmitter, comprising: a multiple-input for receiving a multiple-input signal; a matrix of pre-processing cells for generating a pre-distorted multiple-input signal from the received multiple-input signal; and a multiple-output for feeding the pre-distorted multiple-input signal to the multiple-input and multiple-output transmitter.

Abstract: A receiver is an ATSC (Advanced Television Systems Committee)-receiver and comprises a staggered quadrature amplitude modulator for providing an staggered quadrature amplitude modulated (SQAM) signal from a received signal; a data-aided carrier tracking loop (CTL) and a data-aided symbol timing recovery (STR) loop. The data-aided STR loop operates such that the data-aided STR loop is now insensitive to carrier phase offset.

Abstract: An OFDM system generates a channel estimate in the time domain for use in either a frequency domain equalizer or in a time domain equalizer. Preferably channel estimation is accomplished in the time domain using a locally generated reference signal. The channel estimator generates an initial estimate from a cross correlation between the time domain reference signal and an input signal input to the receiver and generates at least one successive channel estimate. Preferably the successive channel estimate is determined by vector addition (or subtraction) to the initial channel estimate. The at least one successive channel estimate reduces the minimum mean square error of the estimate with respect to a received signal.

Abstract: A method of designing a reference signal pattern for a network in a wireless communication system is disclosed. The method comprises transmitting a plurality of cell-specific reference signal (CRSs) in a subframe, the subframe comprising a plurality of resource elements that are divided in time across a plurality of subcarriers to form a plurality of orthogonal frequency division multiplexed (OFDM) symbols, each of the plurality of resource element occupying a predetermined amount of time on a respective one of the plurality of subcarriers. wherein, a first set of the plurality of CRSs is allocated to a first set of the plurality resource elements on a first symbol and a second symbol over a third subcarrier, a sixth subcarrier, a ninth subcarrier and a twelfth subcarrier.

Abstract: In an embodiment, a multi-carrier signal (e.g., an OFDM signal) is received over a channel. Indicators of interference and the channel response at a carrier frequency of the signal are determined, and compared. If the indicator of interference has a particular relationship to the indicator of the channel response, then a data value transmitted at the carrier frequency is recovered from a data value received at the carrier frequency according to a particular data-recovery algorithm. Because the particular data-recovery algorithm may be faster than a conventional data-recovery algorithm, recovering one or more data values with the particular algorithm may increase the speed at which data is recovered from a multicarrier signal as compared to using a conventional data-recovery algorithm.

Abstract: A transmitter includes an equalizer for conditioning a data signal in response to a first and a second equalizer setting. The first and second equalizer settings are both associated with a selected point on a two-dimensional search grid. The search grid includes a first equalizer setting and a second equalizer setting for each point on the search grid. The transmitter transmits a data signal across a first channel medium using settings associated with a selected point on the search grid. A receiver analyzes the received signal from the transmitter to determine a signal quality metric. The search grid is used to select settings from neighboring points to produce signals that are evaluated to produce signal quality metrics. The results of the evaluations are used to efficiently search the search grid for optimum equalizer settings for the transmitter.

Abstract: In OFDMA wireless communications systems, pilot pattern design is optimized based on predefined resource block size. The number of pilots and the spacing between pilots within a resource block is determined based on a set of system requirements. In one novel aspect, if resource block size is smaller than three in either frequency or time domain, then the pilots are allocated such that average pilot-to-data distance is minimized and that pilot-to-pilot distance is as large as possible. In one example, m pilots are allocated in an i×j resource block. The resource block is partitioned into n equal sub blocks, where m is a multiple of n. Within each sub block, m/n pilots are positioned such that average pilot-to-data distance is minimized. On the other hand, if resource block size is larger than or equal to three in both frequency and time domain, then pilots are allocated to avoid channel extrapolation.

Abstract: A system that incorporates teachings of the subject disclosure may include, for example, a method for identifying a spectral region in a radio frequency spectrum for initiating a communication session having a transmission link and a reception link, determining a correlation factor from signals measured in the spectral region, detecting according to the correlation factor a foreign communication signal in the spectral region, generating coefficient data to prevent interference with the foreign communication signal while transmitting in the transmission link, filtering a first signal for transmission in the transmission link according to the coefficient data to generate a filtered signal, and causing a transmission of the filtered signal which prevents interference with the foreign communication signal while transmitting in the transmission link. Other embodiments are disclosed.

Abstract: In OFDMA wireless communications systems, pilot pattern design is optimized based on predefined resource block size. The number of pilots and the spacing between pilots within a resource block is determined based on a set of system requirements. In one novel aspect, in a high-rank MIMO system, pilots are allocated within a resource block to avoid channel extrapolation in frequency domain only. Because high-rank MIMO only supports low-mobility environment, time-domain extrapolation is no longer a dominant factor. For uplink transmission, one or more frequency tones at one or more edges of the resource block are reserved to be pilot-free to reduce multiuser synchronization error effect. When continuous resource blocks are jointly used for channel estimation, the upper and lower edges of each resource block are left with blanks such that edge pilots of adjacent resource blocks are not too close to each other to improve channel estimation.

Abstract: Providing for improved tracking and correction of timing in wireless communications is disclosed herein. By way of example, a first algorithm can be employed to track timing of a wireless signal, based on one dimension of the signal. Additionally, a second algorithm based on a different dimension of the signal can be employed to verify the timing and reduce errors in timing analysis. Various signal dimensions can be employed for the analysis, including cyclic prefix, frequency, channel impulse response, or the like, or a combination thereof. Additionally, different channels of the wireless signal can also be analyzed by the first algorithm and the second algorithm. Furthermore, the second algorithm can be selected to reduce deficiencies identified in the first algorithm, to improve overall timing analysis, reduce undetected timing errors or false errors, and improve timing correction.

Abstract: In an embodiment, a multi-carrier signal (e.g., an OFDM signal) is received over a channel. First indicators of interference and channel response at a carrier frequency of the signal are determined and compared. If the first indicator of the interference has a relationship to the first indicator of the channel response, then a data value transmitted at the carrier frequency is recovered from a data value received at the carrier frequency according to a first algorithm. If, however, the first indicator of the interference does not have a first relationship to the first indicator of the channel response, then second indicators of interference and the channel response at the carrier frequency are determined and compared. If the second indicator of the interference has a second relationship to the second indicator of the channel response, then the data value transmitted at the carrier frequency is recovered from the data value received at the carrier frequency according to a second algorithm.

Abstract: In the present invention, the overhead data transmission rate in a multicarrier communication system (1) may be changed and/or selected. More specifically, this rate may be selected during an initial negotiation process and/or during a steady state mode of operation.

Abstract: A VCO of a PLL outputs a first differential signal of frequency FVCO. A first divide-by-two circuit local to the VCO divides the first differential signal and outputs a first quadrature signal of frequency FVCO/2. Two of the component signals of the first quadrature signal are routed to a second divide-by-two circuit local to a first mixer of a first device. The second divide-by-two circuit outputs a second quadrature signal of frequency FVCO/4 to the first mixer. All four signals of the first quadrature signal of frequency FVCO/2 are routed through phase mismatch correction circuitry to a second mixer of a second device. In one example, FVCO is a tunable frequency of about ten gigahertz, the first device is an IEEE802.11b/g transmitter or receiver that transmits or receives in a first band, and the second device is an IEEE802.11a transmitter or receiver that transmits or receives in a second band.

Abstract: A method for wireless data transmission, in, for example, RFID systems, between a base station and a passive transponder, as well as a passive transponder is provided by inductive coupling, as well as a passive transponder. It is possible to transmit data from the base station to the transponder by a first data transmission protocol type and by at least one second data transmission protocol type, whereby the first or the at least second data transmission protocol type is selected by writing a configuration register in the transponder.

Abstract: A multi-carrier transmitter capable of transmitting on one or multiple frequency channels simultaneously is described. In one design, the multi-carrier transmitter includes at least one processor and a single radio frequency (RF) transmit chain. The processor(s) may generate output chips for each of multiple frequency channels, digitally filter and upsample the output chips for each frequency channel to obtain filtered samples, and digitally upconvert the filtered samples for each frequency channel to a different frequency to obtain upconverted samples. The processor(s) may then combine the upconverted samples for the multiple frequency channels to obtain composite samples, perform pre-distortion on the composite samples for I/Q mismatch compensation, and upsample the pre-distorted samples to obtain output samples. The output samples may be converted to an analog signal with a wideband DAC. The RF transmit chain may process the analog signal to generate an RF output signal.

Abstract: In various embodiments, a first and second complex multiplier may be configured to receive an input signal and provide a baseband I component signal and a baseband Q component signal, respectively. A first and second filter may be configured to filter the baseband I component signal and the baseband Q component signal, respectively. An equalizer may be configured to equalize the filtered baseband I component signal and the filtered baseband Q component signal. A carrier recovery portion may be configured to generate a reference signal based on the equalized filtered baseband I component signal and the equalized filtered baseband Q component signal. A first and second multilevel comparator may be configured to receive the equalized filtered baseband I component signal from the carrier recovery portion and provide an output I and receive the equalized filtered baseband Q component signal and provide an output Q signal for further modulation.