Patent application number | Description | Published |
20080273583 | CHANNEL ESTIMATION FOR OFDM-BASED WIRELESS COMMUNICATION SYSTEM USING SPARSELY SPACED PILOT SUBCARRIERS - A device and method for performing a channel estimation for an OFDM-based wireless communication system using sparsely spaced pilot subcarriers estimates missing pilot subcarriers in an interpolation window using pilot subcarriers that are outside of the interpolation window to produce estimated pilot subcarriers for the interpolation window. The pilot subcarriers in the interpolation window and the estimated pilot subcarrier are used to compute pilot channel estimates for the interpolation window, which are then used to derive data channel estimates for the interpolation window. | 11-06-2008 |
20080273615 | CHANNEL PROFILE ESTIMATION FOR OFDM-BASED COMMUNICATION SYSTEM - A device and method for performing a channel profile estimation for an OFDM-based wireless communication system uses an averaged frequency coherence metric to select a particular channel profile, which is a current channel profile estimate. The averaged frequency coherence metric is derived using correlations between pilot subcarriers of an OFDM-based signal at predefined subcarrier locations for multiple frames of the OFDM-based signal. The selected channel profile may be used for channel estimation, as well as for link adaptation, to improve the performance of these processes. | 11-06-2008 |
20080273631 | TURBO DECODER AND METHOD FOR TURBO DECODING A DOUBLE-BINARY CIRCULAR RECURSIVE SYSTEMATIC CONVOLUTIONAL ENCODED SIGNAL - A Turbo decoder and method for decoding a double-binary circular recursive systematic convolutional (DBCRSC) encoded signal with unknown initial and final states executes iterations of forward and backward recursion on a payload block of the DBCRSC encoded signal and a padded block using an estimated forward state metric (FSM) and an estimated backward state metric (BSM), which are updated at one or more iterations. | 11-06-2008 |
20080273636 | AUTOMATIC GAIN CONTROL CIRCUIT FOR MIMO OFDM RECEIVER - An automatic gain control (AGC) circuit and method for performing AGC for an orthogonal frequency-division multiplexing (OFDM) receiver measures signal power of input digital signals that are derived from incoming data frames with preambles to produce gain change signals when the signal power differs from a reference target power level. The gain of an amplifier of the OFDM receiver is changed in response to the gain change signals until a preamble of the data frames is detected for the first time. The gain of the amplifier of the OFDM receiver is further changed in response to the gain change signals, after the preamble is detected, only during periods when the preambles of the data frames are being processed by the OFDM receiver such that the gain of the amplifier is not changed during periods when other portions of the data frames are being processed by the OFDM receiver. | 11-06-2008 |
20080273641 | OFDM-BASED DEVICE AND METHOD FOR PERFORMING SYNCHRONIZATION - An OFDM-based device and method for synchronizing to a serving base station utilizes at least one of three frequency offset estimation techniques, which are each based on preambles, cyclic prefixes or pilot subcarriers. The device and method also utilizes a base station selecting scheme, a false detection scheme, a blocker detection scheme to provide robust synchronization. | 11-06-2008 |
20080291819 | SOFT-BIT DE-MAPPING DEVICE AND METHOD OF GENERATING SOFT BITS FOR DECODING - A soft-bit de-mapping device and method of generating soft bits for decoding quantizes a log-likelihood ratio (LLR) value for a received value using functions bits and channel parameter bits to generate the soft bits. The function bits are generated by quantizing an LLR function for the received value, which includes modifying an original curve of the LLR function to a modified curve such that a segment of the original curve with the lowest slope is protected in the modified curve for a fixed equal quantization step-size. The channel parameter bits are generated by quantizing a channel parameter for the received value to generate channel. | 11-27-2008 |
20080291893 | OFDM-BASED DEVICE AND METHOD FOR PERFORMING SYNCHRONIZATION IN THE PRESENCE OF INTERFERENCE SIGNALS - An OFDM-based device and method for performing synchronization utilizes a time-domain preamble of an incoming OFDM-based signal to compute an estimated fine frequency offset. The computation of the estimated fine frequency offset involves multiplying values of the time-domain preamble with conjugates of corresponding values of a selected base station time-domain preamble, averaging the resulting multiplied values in predefined segments and self-correlating the resulting averaged values to derive a self-correlation value, which is used to compute the estimated fine frequency offset. | 11-27-2008 |
20090129304 | METHOD FOR REDUCING POWER CONSUMPTION IN A MULTI-USER DIGITAL COMMUNICATION SYSTEM AND MOBILE STATION EMPLOYING THE METHOD - A method for reducing power consumption in a multi-user digital communication system and mobile station employing the method adjusts receive and transmit mode durations of the mobile device using downlink and uplink allocations from a base station of the system, as well as other factors. | 05-21-2009 |
20100014504 | Multiple-Input Multiple-Output System And Method - A multiple-input multiple-output (MIMO) system can transmit on multiple antennas simultaneously and receive on multiple antennas simultaneously. Unfortunately, because a legacy 802.11a/g device is not able to decode multiple data streams, such a legacy device may “stomp” on a MIMO packet by transmitting before the transmission of the MIMO packet is complete. Therefore, MIMO systems and methods are provided herein to allow legacy devices to decode the length of a MIMO packet and to restrain from transmitting during that period. These MIMO systems and methods are optimized for efficient transmission of MIMO packets. | 01-21-2010 |
20100111212 | Decision Feedback Channel Estimation And Pilot Tracking for OFDM Systems - Current OFDM systems use a limited number of symbols and/or sub-channels to provide approximations for channel estimations and pilot tracking, i.e. phase estimations. For example, two training symbols in the preamble of a data packet are used to provide channel estimation. Four of the fifty-four sub-channels are reserved for providing phase estimation. However, noise and other imperfections can cause errors in both of these estimations, thereby degrading system performance. Advantageously, decision feedback mechanisms can be provided to significantly improve channel estimation and pilot tracking in OFDM systems. The decision feedback mechanisms can use data symbols in the data packet to improve channel estimation as well as data sub-channels to improve pilot tracking. | 05-06-2010 |
20120039377 | Multiple-Input Multiple-Output System And Method - A multiple-input multiple-output (MIMO) system can transmit on multiple antennas simultaneously and receive on multiple antennas simultaneously. Unfortunately, because a legacy 802.11a/g device is not able to decode multiple data streams, such a legacy device may “stomp” on a MIMO packet by transmitting before the transmission of the MIMO packet is complete. Therefore, MIMO systems and methods are provided herein to allow legacy devices to decode the length of a MIMO packet and to restrain from transmitting during that period. These MIMO systems and methods are optimized for efficient transmission of MIMO packets. | 02-16-2012 |
20120121046 | Repetition Coding For A Wireless System - A system and method are disclosed for transmitting data over a wireless channel. In some embodiments, transmitting data includes receiving convolutionally encoded data and enhancing the transmission of the data by further repetition encoding the data. | 05-17-2012 |
20130177095 | Multiple-Input Multiple-Output System And Method - A multiple-input multiple-output (MIMO) system can transmit on multiple antennas simultaneously and receive on multiple antennas simultaneously. Unfortunately, because a legacy 802.11a/g device is not able to decode multiple data streams, such a legacy device may “stomp” on a MIMO packet by transmitting before the transmission of the MIMO packet is complete. Therefore, MIMO systems and methods are provided herein to allow legacy devices to decode the length of a MIMO packet and to restrain from transmitting during that period. These MIMO systems and methods are optimized for efficient transmission of MIMO packets. | 07-11-2013 |