Patent application number | Description | Published |
20090067549 | Optimal Two-Layer Coherent Demodulation for DPSK (Differential Phase Shift Keying) - A D-PSK demodulator utilizes a two-layer coherent approach to estimate the phase shift of adjacent symbols. There is generated a probability set of each received symbol being one of possible constellation values. There is also generated a probability set of each of possible phase difference between two adjacent symbols. This probability set is then converted into soft bit information according to specific mathematical operation. | 03-12-2009 |
20090217138 | ITERATIVE DECODING OF PACKET DATA - A receiver employs iterative decoding of packet data, where the packet data represents a data frame encoded with at least two logical dimensions. A logical dimension refers to a layer, or sub-layer, of a layered network architecture. Consequently, a first logical dimension of encoding might refer to error detection in a packet frame at the data link layer, while a second logical dimension of coding might refer to error detection/correction encoding at a physical layer. For example, a data frame might be divided into several packets, each with a corresponding cyclic redundancy check (CRC) value as coding in the first logical dimension, which are then transmitted with a convolutional code as coding in the second logical dimension. The receiver performs iterative decoding in the first and second logical dimensions until either i) all errors are identified and corrected or ii) another type of stopping condition is met. | 08-27-2009 |
20090304113 | Optimal Blind Channel Estimation for DQPSK Demodulation - An apparatus and method are described that provide an optimal blind channel estimation approach for a differential quadrature phase shift keying (DQPSK) modulation communication receiving system. The described blind channel estimation technique takes advantage of the characteristics of DQPSK constellations and the fact that estimates of relative channel phase distortion, and not absolute channel phase distortion, are sufficient for a DQPSK demodulation scheme. The described channel estimation approach provides low complexity, offers improved demodulation performance, and is theoretically optimal. It is particularly useful in existing DQPSK-based communications protocols that do not provide sufficient reference symbols for channel estimation. | 12-10-2009 |
20090316053 | MOBILE DIGITAL TELEVISION DEMODULATION CIRCUIT AND METHOD - Pilot processing logic, depending upon which modulation scheme of wireless digital mobile television signals is being received, produces both fractional frequency offset and fractional timing offset for symbols for a respective modulation scheme whether the modulation scheme employs pilot or non-pilot information. As such, in operation, the pilot processing logic will produce both fractional frequency offset and fractional timing offset for symbols from different modulation schemes that employ pilot or non-pilot information so that multiple different modulation schemes of wireless digital mobile television signals can be received by a mobile device, for example, that employs the mobile television demodulating circuit. A dual operation circuit selects the mode of operation, namely the modulation scheme (e.g., T-DMB or DVB-T) of the digital mobile television signal that is being received. | 12-24-2009 |
20100002783 | Blind Channel Estimation for PSK and D-PSK Modulated Multicarrier Communication Systems - An apparatus and method is described that provide an efficient blind channel estimation approach for PSK and DPSK modulated multicarrier communication systems. With the requirement that the channel phase difference between any two adjacent carriers is smaller than one half of the minimum phase difference between two symbols of the PSK or DPSK constellation, a low-complexity deterministic approach to channel estimation is devised. This approach is highly effective, robust, and particularly useful for time varying channels with low AWGN noise. | 01-07-2010 |
20100007802 | FAST STREAM SWITCHING - A method of fast stream switching including receiving at least one first stream at a device corresponding to at least one first program, wherein the device employs dynamic power management and is operating at a first power level; activating a selection panel; receiving a plurality of streams corresponding to a plurality of programs; and adjusting to a second power level. After a stream is selected, the non-selected streams may be deactivated and the device may return to the first power level. | 01-14-2010 |
20100008349 | DYNAMIC POWER MANAGEMENT FOR TIME DIVISION MULTIPLEXING DEVICES - A method of dynamic power management in a time division multiple access (TDMA) system. The method comprising comparing each of a plurality of streams; grouping each of the plurality of streams into a plurality of powergroups, wherein each of the plurality of powergroups may comprise multiple streams, scheduling a burst transmission based on the plurality of powergroups; and adjusting the power stage based on the plurality of powergroups, wherein the system is configured to turn off selected components based on the power stage and the scheduled burst transmissions. | 01-14-2010 |
20100008433 | METHOD AND APPARATUS FOR ADVANCED INTER-CARRIER INTERFERENCE CANCELLATION IN ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (OFDM) CHANNELS - A method of estimating a time variant Orthogonal Frequency Division Multiplexing (OFDM) while eliminating Inter-carrier Interference (ICI) is disclosed, where the time variant channel matrix is estimated at channel taps using a Basis Expansion Model (BEM). The BEM method decomposes the time variant channel into a group of basis functions in the frequency domain. Coefficients are estimated using a sub-space tracking algorithm that decreases the dimensions of the coefficient matrix allowing for simpler calculation of the estimated signal. The coefficients matrix is estimated using a conjugate gradient iterative method that may be stopped after 6-8 iterations to arrive at an acceptable estimation. Finally, the transmitted data is estimated, again using the conjugate gradient method iteratively, wherein the conjugate gradient method is stopped after a small number of iterations. | 01-14-2010 |
20100067618 | D-PSK Demodulation Based On Correlation Angle Distribution - An apparatus and method is described that provides optimal D-PSK demodulation based on the distribution of phase differences between successive D-PSK symbols. A plurality of D-PSK data symbols are received, and each symbol is characterized by a real component and an imaginary component. An angle of correlation between any two successive symbols is calculated. A variance of correlation angles is obtained by using data symbols or pilot symbols, if available. The probability of the correlation angle being each of possible phase difference according the D-PSK constellation is then determined. From the probabilities of the particular correlation angle, a probability of each input bit being a “0” or “1” is determined. | 03-18-2010 |
20100232552 | SYNCHRONIZATION AND ACQUISITION FOR MOBILE TELEVISION RECEPTION - A method for synchronizing a receiver to a received signal begins by down-converting the received signal to a first baseband signal. A coarse frequency offset (CFO) of the first baseband signal is determined and is applied to the down-converting of the received signal to a second baseband signal. A fine frequency offset (FFO) of the second baseband signal is determined. The receiver is synchronized to the received signal using the CFO and the FFO. | 09-16-2010 |
20100238358 | ADJACENT CHANNEL POWER SCAN - A method and apparatus are disclosed for determining the presence of adjacent channel interference. Received digital signals are processed to detect the existence of strong channels adjacent to the channel of interest and control signals may be generated based on the detection of strong adjacent channels. The control signals are then used to adjust the signal power of the received signals. | 09-23-2010 |
20100303156 | Method and Apparatus for Providing Precise Transport Stream Packet Ordering and Erasure Optimization for Digital Video Decoder - One method includes estimating, by a lost packet determination logic, an expected number of packets, expected to be received within a time interval, based on packet arrival speed; and determining a number of lost packets by using the expected number of packets and a packet counter wherein the packet counter counts a plurality of received packets. The method may further include comparing the expected number of packets to the packet counter and determining that the expected number of packets is greater than the packet counter; and then using the expected number of packets and the packet counter to determine the actual number of lost packets, where the actual number of lost packets exceeds the packet counter maximum. The methods may also introduce erasures when there is uncertainty of whether some packets or bytes are in error, such that a simplified erasure-based Reed-Solomon decoder may be used. | 12-02-2010 |