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| 20110026454 | WIRELESS COMMUNICATION SYSTEM - A method of operating a communication system comprises exchanging initial communications between a wireless communication device and a communication network over a wireless connection between the wireless communication device and a network access system and over a network connection between the wireless device and the communication network. The method further comprises, in response to a loss of the network connection due to a deterioration of the wireless connection, determining if a partial network entry process is possible to regain the connection, and if the partial network entry process is possible to regain the network connection, performing the partial network entry process. The method further comprises, in response to an improvement of the wireless connection and upon regaining the network connection, exchanging new communications between the wireless communication device and the communication network over the wireless connection and the network connection. | 02-03-2011 |
| 20110026455 | WIRELESS COMMUNICATION SYSTEM - A method of operating a communication system comprises exchanging initial communications between a wireless communication device and a communication network over a wireless connection between the wireless communication device and a network access system and a network connection between the wireless communication device and the communication network. The method further comprises performing a plurality of ranging processes to monitor a status of the wireless connection. Upon successfully completing a ranging process of the plurality of ranging processes, the method comprises determining a duration elapsed since the last successful ranging process and processing the duration to determine if the duration satisfies a criteria. The method further comprises, if the duration does not satisfy the criteria, then setting the indicator to indicate that a partial entry process is required to regain the network connection, and in response to the deterioration of the wireless link, processing the indicator to determine if the partial network entry process is required to regain the network connection. | 02-03-2011 |
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| 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 |
| 20090316841 | NULL DETECTION AND ERASURE DECODING FOR FREQUENCY SELECTIVE CHANNELS IN A BROADCASTING SYSTEM - A null detection and erasure decoding process for a frequency selective channel in a broadcasting system. An orthogonal frequency-division multiplexing (OFDM) receiver receives an input bitstream, determines a noise level of the received input bitstream, and then detects a null in the input bitstream based on the noise level. Once a null is detected, the presence of the null is signaled to a decoder, allowing the decoder to process the null as an erasure. | 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 |
| 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 |
| 20100014600 | WINDOW POSITION OPTIMIZATION FOR PILOT-AIDED OFDM SYSTEM - A window position optimization for a pilot-aided OFDM system is disclosed. A method of reducing aliasing in an orthogonal frequency division multiplexing (OFDM) system, using window optimization and pilots comprises receiving an RF signal including a pilot, generating a channel frequency response estimate, interpolating the channel estimate to calculate a pilot carrier frequency response, and dynamically selecting a window to capture a channel impulse response to prevent aliasing. | 01-21-2010 |
| 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 |
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| 20080278165 | Method and apparatus for reconstruction of an image in image space using basis functions (RIB) for partially parallel imaging - Embodiments of the invention pertain to a method and apparatus for image reconstruction for parallel Magnetic Resonance Imaging (MRI). In a specific embodiment, a method for image reconstruction in image space is provided. The method can suppress aliasing caused by undersampling when the number of sampling lines in k-space is reduced to increase the imaging speed. In an embodiment, suppressing aliasing from under-sampling can improve the quality of images reconstructed from the data acquired using a MRI coil array. In an embodiment, the method operates in image space and achieves a good resolution. In the reconstruction, the sum of square errors can be minimized within a region of interest, which can allow the image reconstruction to be optimized in a particular imaging region of interest by sacrificing the reconstruction of other regions. In a further embodiment, image reconstruction can be implemented region by region, allowing global optimization by spending a longer time in reconstruction. | 11-13-2008 |
| 20080298661 | Method and Apparatus for Parameter Free Regularized Partially Parallel Imaging Using Magnetic Resonance Imaging - Embodiments of the invention are directed to a method and apparatus for parameter free regularized partially parallel imaging (PPI). Specific embodiments relate to a method and apparatus for high pass GRAPPA (hp-GRAPPA), doubly calibrated GRAPPA (db-GRAPPA), and/or image ratio constrained reconstruction (IRCR). The subject techniques can be applied individually or in combination. In a specific application of an embodiment of the subject method, hp-GRAPPA is used to reconstruct high frequency information, and db-GRAPPA is used reconstruct low frequency information regularized with prior information. In another specific application of an embodiment of the subject method, the result of IRCR a regularization term for db-GRAPPA. Experiments demonstrate that the results obtained by implementing embodiments of the subject method have significantly higher SNR than results obtained utilizing un-regularized techniques and have higher spatial resolution and/or lower error than results obtained using regularized SENSE. The subject double calibration technique lessens the motion problem of the pre-scan even when significant structure change occurs. High quality images generated by a specific embodiment of the subject double calibration technique are demonstrated with a net reduction factor as high as 4.8. | 12-04-2008 |
