Abstract: Systems (600) and methods (100) for demodulating a Gaussian Filtered Minimum Shift Keyed (GMSK) signal. The GMSK signal is defined in a transmitted symbol domain where each symbol is given by a product of a current data bit and a previous data bit. The GMSK signal is converted from the transmitted symbol domain to a data symbol domain. The conversion is achieved by approximating filtered complex output signals that would be produced by matched filters having filter shapes corresponding to pulses used in terms of a Laurent expansion. Subsequent to the convention of the GMSK signal, a trellis equalization of the GMSK signal is performed exclusively in the data symbol domain based on the terms of the Laurent expansion.

Abstract: Improvement of transmission efficiency is sought by stopping transmission of unnecessary MLI data. A transmitting circuit 111 in a base station apparatus 110 has an MLI modulation part 248 composed of an MLI generating circuit 238, a symbol modulation circuit 239, and an IFFT circuit 240, a user data modulation part 249 composed of an encoder circuit 234, a symbol modulation circuit 235, a transmission power control circuit 236, and an IFFT circuit 237, and a transmission operation control circuit 113. The transmission operation control circuit 113 controls operation timing of the MLI modulation part 248, the user datamodulationpart 249, and a multiplexer 243 based on a signal to notify that ACK input from a receiving circuit 112 has been received so that slots containing no MLI data are generated.

Abstract: The disclosed method of processing a digital broadcast signal comprises generating one RS frame or two RS frames for a data group, forming the data group being divided to 5 data regions, wherein the 5 data regions include a first data region which is located at central of the data group, a second data region which is concentric about the first data region, a third data region which is concentric about the first and second data region, a fourth data region which is concentric about the first, second and third data region and a fifth data region which includes scalable amount of the mobile service data, wherein the fifth data region includes 5 extended data blocks, and wherein data in one of the 5 extended data blocks are merged into the data blocks of the first data region when the one RS frame is generated for the data group.

Abstract: A modulator using a polynomial interpolator is described herein. In a simple circuit implementation of the modulator, coefficients of a representative polynomial are generated with interpolation filters in the polynomial interpolator. Crossing points may be identified for each sampling period by incorporating a virtual carrier waveform with the representative polynomial to generate a switching output control. Among other applications, the described modulator may be used in a Class-D amplifier. The described implementations may further confer benefits such as micro-power low voltage operation, low sampling rate, and low harmonic distortion.

Abstract: Different sets symbols are precluded at prescribed times in time-dependent trellis coding. This increases the distances between different individual symbols as well as the distances between trellis codes, which increases the robustness of data transmission. The symbols that are precluded in this time-dependent trellis coding are determined in advance according to a prescribed pattern, which pattern does not depend on the history of previous symbols. The Viterbi decoder used for trellis decoding in a receiver can be designed to take advantage of knowledge concerning which different sets of symbols are precluded at prescribed times.

Abstract: A method and apparatus are provided for testing susceptibility of a receiver to intermodulation distortion of a digital channel, the method including selecting a first digital channel from channels in a composite signal, determining a first power measurement from the first digital channel, determining a total power measurement from other channels in the composite signal, and determining susceptibility of the first digital channel to intermodulation distortion by comparing the first power measurement and the total power measurement with intermodulation distortion characteristics of the receiver.

Abstract: A video transmission system includes a transceiver module that transmits a video signal to a remote device over at least one communications channel wherein the video signal is transmitted as at least one separate video layer stream chosen from, an independent video layer stream and at least one dependent video layer streams that require the independent video layer for decoding. A control module determines at least one channel characteristic of the at least one channel and chooses the at least one separate video layer stream based on the at least one channel characteristic of the at least one channel.

Abstract: A clock extractor extracts clock frequency f2, from a wired data connection. A clock error estimator estimates a first clock frequency error between clock frequency f2 and a clock frequency f1 associated with a local clock of the transmitter. A transmitter sends the first clock frequency error, as a message to a receiver. The transmitter uses a wireless transmitter interface, including a modulator and transmitter radio. The wireless transmitter interface is clocked at clock frequency f1. The transmitter sends data to the receiver. A wireless receiver interface includes a de-modulator and receiver radio. The wireless receiver interface reconstructs clock frequency f1. A clock adder adds the reconstructing clock frequency f1 to the first clock frequency error, resulting in a synthesized clock frequency f2. The receiver clocks a second wired data connection, using the synthesized clock frequency f2.

Abstract: Methods and apparatus for avoiding overflow and underflow conditions through the determination of appropriate scaling factors in signal estimation processing in a receiver are described. The receiver estimates transmitted symbols from one or more transmitter device antennas, while avoiding underflow and overflow conditions. A pilot based noise estimate and an estimated expected received signal power, corresponding to a transmit antenna, are used to generate an SNR corresponding to the transmit antenna. The generated SNR is used to determine, e.g., select from a fixed size set of predetermined scale factor values, a scale factor to be used for estimation processing associated with the transmit antenna. In some embodiments, the generated scaling factors are used by a fixed point processing linear least squares error estimation module. Scaling factor determination is performed at a rate which is slower than the rate at which symbols are received from a transmit antenna.

Abstract: A Signal Conditioning Filter (SCF) and a Signal Integrity Unit (SIU) address the coupled problem of equalization and noise filtering in order to improve signal fidelity for decoding. Specifically, a received signal can be filtered in a manner to optimize the signal fidelity even in the presence of both significant (large magnitudes of) ISI and noise. The present invention can provide an adaptive method that continuously monitors a signal fidelity measure. Monitoring the fidelity of a multilevel signal can be performed by external means such as by the SIU. A received signal y(t) can be “conditioned” by application of a filter with an electronically adjustable impulse response g(t). A resulting output z(t) can then be interrogated to characterize the quality of the conditioned signal. This fidelity measure q(t) can be used to adjust the filter response to maximize the fidelity measure of the conditioned signal.

Abstract: Systems and methods detect a communication received at receiving antennas from transmitting antennas. Each transmitting antenna transmits a symbol in a constellation. A sphere detector performs a depth-first search until the depth-first search terminates in response to a terminate signal requesting the result from the sphere detector. The depth-first search evaluates respective distances of one or mode leaf nodes in response to the communication received at the receiving antennas. The depth-first search selects the result from these nodes in response to the respective distances. The result includes a selected leaf node that identifies a corresponding symbol in the constellation for each transmitting antenna, with this symbol detected as transmitted by the transmitting antenna.

Abstract: Systems and methods for removing a DC offset from an orthogonal frequency division multiplexed (OFDM) signal transmitted over a plurality of subcarrier frequencies. The system includes a receiver. The system further includes a high pass DC component filter configured to reduce a DC component of the orthogonal frequency division multiplexed signal, the high pass DC component filter shaping noise in the orthogonal frequency division multiplexed signal which results in a non-uniform power spectral density of the noise across the plurality of subcarrier frequencies. The system further includes a noise whitener configured to compensate for the noise shaping by the high pass DC component filter by normalizing the non-uniform power spectral density of the noise across the plurality of subcarrier frequencies.

Abstract: A method for transmitting scattered pilot signals in a multi-carrier system is disclosed. The method includes: in each time slot, in time dimension, putting each 4 OFDM symbols into a group according to the order of the OFDM symbols; in each group of OFDM symbols, in frequency dimension, selecting, for each OFDM symbol, a plurality of valid sub-carriers to transmit scattered pilots, wherein for a same OFDM symbol, between each 2 valid sub-carriers selected, there are 7 valid sub-carriers; for different OFDM symbols in a same group, the valid sub-carriers selected are interleaving in frequency domain; and transmitting scattered pilot signals on the valid sub-carriers selected. The solution helps the multi-carrier system to handle multi-path channel with large delay spread, to obtain more accurate channel estimation and to achieve better receiving performance.

Abstract: A reception station 1b compares its BSSID with BSSID included in a signal that has arrived thereat. As BSSIDs included in signals transmitted by interfering stations 1c and 1d both match BSSID of the reception station 1b, the reception station 1b identifies each of the interfering stations 1c and 1d as a non-suppression target transmission source. As neither of BSSIDs included in signals transmitted by interfering stations 2a and 2b matches BSSID of the reception station 1b, the reception station 1b identifies each of the interfering stations 2a and 2b as a suppression target transmission source. The reception station 1b uses characteristic amounts of signals that are associated with the interfering stations (i.e., suppression target transmission sources) 2a and 2b and that have been measured in the past as characteristic amounts of interfering signals that are used to suppress the interfering signals from a received signal.

Abstract: A new channel is added to FLO networks that carries embedded signaling parameter information. The design is such that regardless of the actual values of the signaling parameters conveyed, a receiver will be able to demodulate this new channel. Moreover, the addition of the new channel does not render a FLO network that has been so configured to not be backwards-compatible with existing devices.

Abstract: In a multi user communication system, subcarriers are allocated to subchannels using a quality measurement for each subchannel. An initial sub carrier is allocated to each subchannel, and a quality metric measured. Subsequent subcarriers are allocated in dependence upon the quality measurement for each subchannel. The subchannel with the lowest quality measurement receives the first allocation, and the subchannel with the highest quality measurement receives the last allocation. The subsequent allocation is repeated, following a re-sort of the subchannel quality measurements, until all of the subcarriers are allocated.

Abstract: This mobile radio communication device comprises pilot symbol number determination unit 102 for determining the number of pilot symbol blocks necessary to determine a channel estimate in response to phasing variation, storage unit 104 for storing said determined number of pilot symbol blocks, and unit 103 for using said stored number of pilot symbol blocks to determine a channel estimate when said determined number of pilot symbol blocks exceeds the predetermined number of pilot symbol blocks.

Abstract: A 4× over-sampling data recovery system consists of a charge pump PLL, a 4× over-sampler, a data regenerator and a digital PLL. The charge pump PLL receives a clock signal and generates a plurality of multiplicative clock signals in response to the clock signal. The 4× over-sampler samples a serial data to generate a M-bit signal according to the plurality of multiplicative clock signals, wherein each bit in the serial data is sampled for four times. The data regenerator sequentially receives and combines two M-bit signals to generate a (M+N)-bit signal. The digital PLL divides the (M+N)-bit signal into (N+1) groups of M-bit data and selects a designated M-bit data from the (N+1) groups of M-bit data to generate a P-bit recovery data.

Abstract: To make efficient use of a frequency spectrum, a peer-to-peer network shares a wide area network (WAN) frequency spectrum as well as a time-frequency structure of the WAN, where the time-frequency structure includes a set of tones and symbols. A first wireless terminal monitors the time-frequency structure of the WAN to determine which subsets of tone-symbols are unused for WAN and/or other peer-to-peer connections. Then, the first wireless terminal selects and uses an unused subset of tone-symbols within the time-frequency structure for its peer-to-peer connection with a second wireless terminal.

Abstract: Methods and apparatus for reducing high-frequency events in polar domain signals. An exemplary method includes first generating an unmodified rectangular-coordinate signal having in-phase (I) and quadrature phase (Q) components that are modulated according to a predetermined modulation scheme. Next a first sample of the unmodified rectangular-coordinate signal is modified based on how close the first sample is to the origin in the complex signal plane and how fast a signal trajectory between the first sample and a subsequent sample changes. Finally, the modified rectangular-coordinate signal is converted to a polar domain signal having amplitude and phase components. By modifying the first sample in this manner, either or both the amplitude and phase components have reduced high-frequency content compared to a polar domain signal that would be generated without the first sample having been first modified.