Abstract: In a wireless communication system using multiple antennas at the transmitter and multiple antennas at the receiver, a so called multiple-input multiple-output (MIMO) system, a substantial improvement in capacity over the case of no feedback can be achieved using considerably less bandwidth than is required to feedback the channel estimate or channel statistics, by supplying as feedback for each data substream of an overall data stream an indicator of a rate and/or an indicator of a gain for transmission of that data substream. The indicator of the rate and/or the indicator of the gain may be the rate and/or gain directly or an encoded representation of the rate and/or gain. Typically, the best performance is achieved if indicators of both the rate and the gain are fed back. If the invention is implemented for wireless systems, then typically for each data substream there is a separate, independent antenna.

Abstract: A mobile station configured to perform MIMO communication is disclosed, where the mobile station includes a control unit configured to determine a radio access scheme to be applied, based on at least one of a transmission frequency bandwidth to be used and a transmission stream number used in the MIMO communication.

Abstract: A data modulation method, a data demodulation method, and a method, include obtaining a target frequency band allocated to a transmitting terminal; calculating a precoding codeword index of spectrum shaping according to a codebook corresponding to a current radio scene and the target frequency band, where the codeword index corresponds to a return-to-zero subcarrier sequence, and the return-to-zero subcarrier sequence serves to calculate a precoding vector for modulating data; and sending the precoding codeword index out through broadcast.

Abstract: Provided is a method and system for estimating a channel in a wireless communication system. An interference coefficient is calculated based on a known structure of a pilot, and a channel value in a frequency domain is estimated. A channel value in a time domain is obtained by transforming the channel value in the frequency domain and the channel delay values are subtracted from the channel value in the time domain, thereby cancelling interference.

Abstract: A channel estimation method for use with a received signal by a receiver is disclosed. The received signal comprises multiple data bursts which are transmitted to the receiver via multiple path channels, with each of the data bursts having a plurality of preamble symbols which are decoded. The channel estimation method includes the following steps: firstly, at least one correlation pattern is generated according to the decoded preamble symbols. Then, a cross correlation of the correlation pattern with the received signal is performed to yield at least one correlation result of channel impulse response (CIR). Wherein, the symbol boundary of the received signal is decided according to the correlation result.

Abstract: Uplink overhead is significantly reduced in a MU-COMP wireless communication network by exploiting the dissimilarity of received signal strength in signals transmitted by geographically distributed transmit antennas, as seen by receiving UEs. Each UE calculates a quantized normalization measure of channel elements for a channel weakly received from a first transmitter to that for a channel strongly received from a second transmitter. The quantized normalization measure may be modeled as a ratio of complex Gaussian variables, and quantized in phase and amplitude by making simplifying assumptions. The ratios are quantized, and transmitted to the network using far fewer bits than would be required to transmit the full channel state information. The network uses the quantized normalization measures to set the transmitter weights.

Abstract: A method in a mixed-signal system to prevent overlapping of clock edges of one or more digital clock signals and clock edges of one or more analog clock signals where the digital clock signals and the analog clock signals are digitally controlled includes generating one or more timing window pulses that are centered around the clock edges of one of the digital clock signals or the analog clock signals; combining the timing window pulses to generate a gating signal, the gating signal having an active logical level at each of the timing window pulses; and applying the gating signal to gate or delay clock edges of the other one of the digital clock signals or the analog clock signals.

Abstract: A digital broadcasting receiving system and method, where the digital broadcasting receiving system includes: a demodulator receiving and demodulating a dual transmission stream including a turbo stream and a normal stream; an equalizer equalizing the demodulated dual transmission stream; a first processor restoring normal stream data from the equalized dual transmission stream; and a second processor restoring turbo stream data from the equalized dual transmission stream and eraser decoding the turbo stream data. Thus, the reception sensitivity of a transmission stream including a turbo stream can be improved.

Abstract: An automatic gain control (AGC) system and corresponding method is configured to increase signal to noise which may be referred to as signal to noise ratio in a receiver. The AGC system includes: a signal level detector for determining a signal level for a desired signal; a wideband signal detector for determining a wideband signal level of a wideband signal, the wideband signal being indicative of an interfering signal being present; and a controller coupled to both detectors and configured to provide one or more AGC signals to the receiver to establish a gain setting for the receiver, wherein an initial AGC setting for the receiver is based on the signal level, and AGC adjustments, based e.g., on one or more of the signal level and the wideband signal level, are provided such that an adjusted AGC setting for the receiver increases the signal to noise.

Abstract: A receiving apparatus for receiving a downlink signal in which pilot symbols are mapped discontinuously, includes: a unit configured to extract reference signals from the downlink signal that is Fourier transformed by a Fourier transform unit; a unit configured to generate a first signal having a first window size by arranging the extracted reference signals on the frequency axis and by performing inverse Fourier transform on the reference signals; a unit configured to divide the first signal into a plurality of signals to extract a signal included in a second window; a unit configured to generate a second signal that includes the signal included in the second window and that has a window size similar to the first window size; a Fourier transform unit configured to generate a third signal from the second signal; and a unit configured to calculate received power based on the third signal.

Abstract: An embodiment is a method and apparatus to decode a signal using channel information. A channel state estimator generates a tone value representing channel information. A quantizer quantizes the tone value. A combiner combines de-interleaved symbols weighed by the quantized tone value. A comparator compares the combined de-interleaved symbols with a threshold to generate a decoding decision. Another embodiment is a method and apparatus to decode a signal using averaging. A channel estimator provides a channel estimate. A multiplier multiplies a quantized output of a demodulator with the channel estimate to produce N symbols of a signal corresponding to a carrier. A de-interleaver de-interleaves the N symbols. An averager averages the N de-interleaved symbols to generate a channel response at a carrier.

Abstract: A mixed-signal radio frequency receiver implements multiple spur avoidance modes to reduce or remove spurs or digital noise injection into the received channel to enhance the receiver performance. The multiple spur avoidance modes are reconfigurable to allow a single mode or multiple modes to be selected for use depending on the application. One or more spur avoidance modes can be selected to enhance the performance of the receiver or the modes can be selected to reduce power consumption. The same spur avoidance circuit is used to support all of the spur avoidance modes by reconfiguring the circuit for each mode or each combination of modes. In another embodiment, a clock masking scheme is applied to align analog and digital clock edges to separate digital activities from sensitive analog activities.

Abstract: The disclosure can provide methods and systems for autocalibrating a transceiver. The method can include upconverting a bandpass input signal by mixing the bandpass input signal with a first local oscillator signal to form an initial transmitter signal. The initial transmitter signal can be looped back to a receiver and downconverted with a second local oscillator signal having a frequency that is different from the first local oscillator to form an intermediate frequency signal. At least one of a gain and a phase of the transmitter can be adjusted based on a transmitter image sideband of the intermediate frequency signal to generate a calibrated transmitter signal having minimized transmitter image sideband.

Abstract: Methods of transmitting and receiving information in a telecommunications network are described. A method of transmitting, for example, includes identifying a message for transmission, the message selected from a plurality of predetermined messages, and selecting a code combination from a set of codes combinations, each code combination corresponding to a predetermined message. Data is encoded with the selected code combination, and the encoded data is transmitted. A method of receiving may include receiving the signal including data encoded for transmission with the selected code combination, and decoding the signal to retrieve unencoded data, the decoding including determining with which code combination selected from the set of code combinations the data is encoded. The data is decoded, and the message for transmission is selected from the plurality of predetermined messages, wherein the message is selected based on the code combination with which the data was encoded.

Abstract: Methods and systems are provided for timing synchronization for reception of highly-spectrally efficient communications. An example method may include, filtering, in a receiver, a received inter-symbol correlated (ISC) signal to generate a filtered ISC signal. The method may further include locking to a timing pilot signal of the filtered ISC signal. The timing pilot signal may include a sub-harmonic frequency of a clock signal associated with the received ISC signal. A timing pilot estimate signal of the timing pilot signal may be generated. The timing pilot estimate signal may be cancelled from the filtered partial response signal to generate an output ISC signal. The timing pilot signal includes a signal at ±(1/n*Fbaud), where n is an integer greater than 2, and Fbaud is a symbol rate of the clock signal. The clock signal may be recovered from the filtered ISC signal.

Abstract: Embodiments of a system for determining and optimizing the performance a signaling system are described. During operation, the system captures or measures a single-bit response (SBR) for the signaling system. Next, the system constructs an idealized inter-symbol-interference-free (ISI-free) SBR for the signaling system which is substantially free of inter-symbol-interference (ISI). The system then calculates an ISI-residual from the captured SBR and the idealized ISI-free SBR. Next, the system constructs a calibration bit pattern for the signaling system that is based substantially on the ISI-residual. Finally, the system uses the calibration bit pattern to calibrate, optimize and determine an aspect of the performance of the signaling system.

Abstract: In general, the subject matter described in this specification can be embodied in methods, systems, and program products for identifying data that is designated for wireless transmission to a remote computing device. A digital signal that encodes the data for transmission across a band of radio frequency channels is generated. Multiple radio frequency channels in the band that are available are determined. The digital signal is filtered to substantially reduce a power level of the digital signal at frequencies that correspond to channels in the band that have not been determined to be available. The filtered digital signal is converted to an analog signal. The analog signal is provided to an analog transmitter that isolates the band of channels to generate an isolated analog signal and that wirelessly transmits the isolated analog signal over the multiple available channels using one or more antennas.

Abstract: A receiver is equipped with an adaptive phase-offset controller and associated timing-calibration circuitry that together shift the timing for a data sampler and a digital equalizer. The sample and equalizer timing is shifted to a position with less residual inter-symbol interference (ISI) energy relative to the current symbol. The shifted position may be calculated using a measure of signal quality, such as a receiver bit-error rate or a comparison of filter-tap values, to optimize the timing of data recovery.

Abstract: A receiver timing error recovery loop expands the bandwidth of a received signal and determines the timing error based on the bandwidth expanded received signal.

Abstract: A waveform-adaptive ultra-wideband (UWB) transmitter and noise-tracking UWB receiver for use in communications, object detection and radar applications. In one embodiment, the output of an oscillator is gated by a low-level impulse generator either directly or through an optional filter. In a special case of that embodiment wherein the oscillator is zero frequency and outputs a DC bias, a low-level impulse generator impulse-excites a bandpass filter to produce an UWB signal having an adjustable center frequency and desired bandwidth based on a characteristic of the filter. In another embodiment, the low-level impulse signal is approximated by a time-gated continuous-wave oscillator to produce an extremely wide bandwidth pulse with deterministic center frequency and bandwidth characteristics. The low-level impulse signal can be generated digitally. The UWB signal may be modulated to carry data, or may be used in object detection or ranging applications.