| Patent application number | Description | Published |
|---|
| 20080205333 | UPLINK SCHEDULING FOR FAIRNESS IN CHANNEL ESTIMATION PERFORMANCE - Systems and methodologies are described that facilitate mitigation of interference through uplink scheduling in a wireless communication environment. Access points can assign multiple terminals to a single tile or segment of shared resource (e.g., a time frequency region) to maximize the number of terminals supported. However, combinations of certain types of terminals can cause a significant increase in interference. In particular, allocating multiple terminals having a relatively high velocity (e.g., terminals located in moving vehicles) to a single tile can cause an unacceptable increase in interference. To mitigate interference, high velocity terminals can be identified. Once identified, terminals can be allocated to the available tiles based at least in part upon avoiding combinations that result in a significant increase in interference. | 08-28-2008 |
| 20080242294 | DETERMINING PER SECTOR RECEIVED POWER LEVEL - At a mobile device, a total received power represents signals received from all access points. In order to calculate an appropriate transmit power for communication with a single access point, a mobile device determines a per sector received power level. The mobile device can ascertain a time-domain channel response from each access point pilot signal, ascertain a received digital power lever per sector from each access point pilot signal and, based in part on the digital power level, calculate a received power level from each access point. A per sector received power level can be utilized to conserve battery power and/or to reduce interference in a wireless communications network. | 10-02-2008 |
| 20080242337 | DIGITAL AND ANALOG POWER CONTROL FOR AN OFDMA/CDMA ACCESS TERMINAL - Aspects describe controlling a power level for an access terminal in a wireless communication system that utilizes multiple modulation waveforms. The power can be controlled after an Access Grant is received in response to an Access Probe until the mobile device transitions into a steady state. A reference power can be continuously monitored and a setting of a power amplifier can be modified only when the reference power changes. A digital gain of a reverse data channel can be adjusted relative to the reference power level. | 10-02-2008 |
| 20080298452 | FAST SQUARE ROOT ALGORITHM FOR MIMO EQUALIZATION - Systems and methodologies are described that facilitate equalization of received signals in a wireless communication environment. Using multiple transmit and/or receive antennas and MIMO technology, multiple data streams can be transmitted within a single tone. During equalization, receivers can separate data received within a tone into individual data streams. The equalization process generally is computationally expensive. Equalizer functions include the inverse operation, which can be computed using the fast square root method; however, the fast square root method involves large numbers of computations for a set of matrices, where the size of a matrix in the set of matrices increases with the number of transmit or receive antennas. Utilizing a modification of the fast square root method, a subset of the elements of the matrices can be selected and updated to reduce the number and/or complexity of computations. | 12-04-2008 |
| 20090213950 | PILOT SIGNAL TRANSMISSION FOR AN ORTHOGONAL FREQUENCY DIVISION WIRELESS COMMUNICATION SYSTEM - Transmission patterns for pilot symbols transmitted from a mobile station or base station are provided. The pattern allows for improved receipt of the pilot symbols transmitted. In addition, schemes for improving the ability to multiplex pilot symbols without interference and/or biasing from different mobile stations over the same frequencies and in the same time slots. | 08-27-2009 |
| 20100074219 | Methods and Apparatus for Reverse Link Timing Correction - Methods and apparatus for reverse link timing correction in a wireless communication device. In particular, when a handoff of the device from a first sector currently serving the device to a second sector not currently serving the device is detected, a first function linking timing correction of a reverse link of the device to forward link timing corrections is changed to a second function for timing correction. In particular, the second function is configured to correct reverse link timing during a time period of either during or for a predetermined period after a handoff of the device from the first sector to the second sector, where the second function is based on a criterion different from criteria of the first function. | 03-25-2010 |
| 20100226303 | METHOD FOR TRANSMITTING MULTIPLE STREAMS IN WIRELESS BROADCAST NETWORKS - Accordingly, a method and apparatus are provided to convert received content into a first stream and a second stream, to transmit said first stream using a first tone and to transmit said second stream using an orthogonal scheme. A layering scheme is used to transmit the base stream covering a smaller area and an enhanced stream is used to cover a large utilizing orthogonal scheme. | 09-09-2010 |
| 20100238902 | Channel Structures for a Quasi-Orthogonal Multiple-Access Communication System - A channel structure has at least two channel sets. Each channel set contains multiple channels and is associated with a specific mapping of the channels to the system resources available for data transmission. Each channel set may be defined based on a channel tree having a hierarchical structure. To achieve intra-cell interference diversity, the channel-to-resource mapping for each channel set is pseudo-random with respect to the mapping for each remaining channel set. In each scheduling interval, terminals are scheduled for transmission on the forward and/or reverse link. The scheduled terminals are assigned channels from the channel sets. Multiple terminals may use the same system resources and their overlapping transmissions may be separated in the spatial domain. For example, beamforming may be performed to send multiple overlapping transmissions on the forward link, and receiver spatial processing may be performed to separate out multiple overlapping transmissions received on the reverse link. | 09-23-2010 |
| 20100284280 | CHANNEL ESTIMATE PRUNING IN PRESENCE OF LARGE SIGNAL DYNAMICS IN AN INTERFERENCE CANCELLATION REPEATER - A method for estimating a feedback channel for a wireless repeater detects changes in a power of a remote signal. When a large power swing in the remote signal is detected, the method operates to discard samples or blocks of samples of the pilot and receive signals and a final channel estimate is generated using undiscarded samples of the pilot and receive signals. Alternately, sub channel estimates are generated using individual blocks of the pilot samples and receive samples. When a large power swing in the remote signal is detected, the method operates to discard one or more sub channel estimates and a final channel estimate is generated using undiscarded sub channel estimates. | 11-11-2010 |
| 20100284445 | INSERTED PILOT CONSTRUCTION FOR AN ECHO CANCELLATION REPEATER - In one embodiment, a device for constructing a pilot signal for use in a wireless repeater where the pilot signal is added to a transmit signal includes one or more pilot generators. Each pilot generator generates a carrier pilot signal associated with a single carrier of the transmit signal and the carrier pilot signals generated by the one or more pilot generators are summed to generate the pilot signal. Each of the one or more pilot generators includes a pilot symbol unit providing multiple data symbols having a predetermined data structure as the carrier pilot signal, a pilot scrambler, a filter, a pilot power determination unit, and a cyclic prefix insertion unit for inserting a cyclic prefix, to the carrier pilot signal. In another embodiment, the pilot symbol unit providing multiple data symbols in frequency domain as the carrier pilot signal. | 11-11-2010 |
| 20100284447 | FREQUENCY DOMAIN FEEDBACK CHANNEL ESTIMATION FOR AN INTERFERENCE CANCELLATION REPEATER INCLUDING SAMPLING OF NON CAUSAL TAPS - A method for estimating a feedback channel for a wireless repeater uses frequency domain channel estimation on samples of a pilot signal and samples of a receive signal. The pilot signal samples may be delayed to align the largest channel tap to a given reference time. A time domain feedback channel is generated by retaining both the causal taps and the non-causal taps of the channel estimate. | 11-11-2010 |
| 20100285733 | WIDEBAND ECHO CANCELLATION IN A REPEATER - A wireless repeater having a receiving antenna for receiving an input signal and a transmitting antenna for transmitting an amplified signal includes first and second front-end circuits and a repeater baseband block coupled between the first and second front-end circuits. The repeater baseband block includes a channel estimation block, an echo canceller implementing time domain echo cancellation, a variable gain stage controlled by a gain control block implementing digital gain control, a first variable delay element introducing a first delay before or after the echo canceller, a second variable delay element introducing a second delay to the output signal. The delayed output signal is coupled to the channel estimation block as a reference signal for estimating the feedback channel, to the echo canceller as a reference signal for estimating the feedback signal, and to the gain control block for monitoring the stability of the repeater. | 11-11-2010 |
| 20100285734 | DUAL-STAGE ECHO CANCELLATION IN A WIRELESS REPEATER USING AN INSERTED PILOT - In one embodiment, a method for providing echo cancellation in a wireless repeater includes: adding the pilot signal to a transmit signal; receiving a receive signal being the sum of a remote signal, a feedback pilot signal and a feedback transmit signal; cancelling the feedback transmit signal from the receive signal using a currently available feedback channel estimate and generating a first echo cancelled signal; generating an updated feedback channel estimate using the first echo cancelled signal and the pilot signal as a reference signal; cancelling the feedback transmit signal and the feedback pilot signal from the receive signal using the updated feedback channel estimate and generating a second echo cancelled signal; and amplifying the second echo cancelled signal as the transmit signal. In another embodiment, the feedback pilot signal is cancelled from the first echo cancelled signal using the updated feedback channel estimate to generate the second echo cancelled signal. | 11-11-2010 |
| 20100285735 | DELAY CONTROL TO IMPROVE FREQUENCY DOMAIN CHANNEL ESTIMATION IN AN ECHO CANCELLATION REPEATER - A wireless repeater has a receiving antenna for receiving an input signal and a transmitting antenna for transmitting an amplified signal where the input signal is a sum of a remote signal and a feedback signal. The repeater includes an echo canceller receiving the input signal and generating an echo cancelled signal by estimating a feedback channel between the transmitting antenna and the receiving antenna and cancelling a feedback signal estimate from the input signal, an amplifier for amplifying the echo cancelled signal and providing the amplified signal to the transmitting antenna, and a variable delay element receiving the echo cancelled signal and introducing a first delay to the echo cancelled signal. The first delay is selected to optimize the estimation of the feedback channel, thereby optimizing the cancellation of the feedback signal. The delayed echo cancelled signal is coupled to the echo canceller as a reference signal for estimating the feedback channel. | 11-11-2010 |
| 20100285736 | FEEDBACK DELAY CONTROL IN AN ECHO CANCELLATION REPEATER - A wireless repeater includes an echo canceller to cancel an estimated feedback amount from an input signal and a delay to delay the input signal. The delay may be selected to decorrelate a remote signal from a signal to be transmitted by the repeater. | 11-11-2010 |
| 20100285737 | GAIN CONTROL OPTIMIZING SINR AND DATA RATE FOR WIRELESS REPEATER - A method for controlling gain in a wireless repeater implementing echo cancellation determines a signal-to-interference-noise-ratio (SINR) of the input and output signals of the repeater and adjusts the gain of the repeater to optimize an achievable data rate and a coverage area of the repeater. The repeater gain may be decreased to increase the data rate and increase the achievable SINR of the output signal while the coverage area is reduced. Alternately, the repeater gain may be increased to decrease the data rate and decrease the achievable SINR of the output signal while the coverage area is increased. | 11-11-2010 |
| 20100285738 | SIGNAL BLANKING FOR IMPROVED FREQUENCY DOMAIN CHANNEL ESTIMATION - A wireless repeater includes a channel estimation block to estimate a feedback channel between the antennas of the repeater using frequency domain channel estimation. The repeater includes a pilot signal blanking circuit to blank out a selected number of samples of the pilot signal to improve the accuracy of the channel estimation. In another embodiment, the repeater replaces T samples of the pilot signal with a cyclic prefix. | 11-11-2010 |
| 20100285740 | STABILITY INDICATOR FOR A WIRELESS REPEATER - A method for monitoring feedback loop stability in a wireless repeater includes measuring a gain control metric in the feedback loop of the repeater periodically for a given time period where the gain control metric is indicative of a loop gain of the feedback loop of the repeater; and monitoring the magnitude of the gain control metric to determine the stability of the feedback loop of the repeater. In operation, a large magnitude of the gain control metric indicates instability in the feedback loop of the repeater. | 11-11-2010 |
| 20100285741 | GAIN ADJUSTMENT STEPPING CONTROL IN A WIRELESS REPEATER - A method for controlling gain in a wireless repeater includes providing one or more gain control metrics where the gain control metrics is indicative of a loop gain of the repeater; measuring the one or more gain control metrics; and adjusting a variable gain of the repeater using a gain adjustment step size being a function of at least the loop gain of the repeater as measured by the one or more gain control metrics. In another embodiment, the gain control algorithm block is configured to divide the loop gain of the repeater into multiple gain adjustment control zones. The gain adjustment control zones may include a first zone having a loop gain in a stable operating region and a second zone having a loop gain outside the stable operating region. | 11-11-2010 |
| 20100285742 | GAIN CONTROL METRIC PRUNING IN A WIRELESS REPEATER - A method for controlling gain in a wireless repeater includes computing a gain control metric indicative of a loop gain of the repeater and detecting changes in a signal power of a gain control input signal where the gain control input signal is taken from any point in the feedback loop of the repeater. When a large power swing in the gain control input signal is detected, the method operates to discard at least a portion of each gain control metric measurement for a first duration before continuing with computing the gain control metric. In another embodiment, the method may include discarding samples of the gain control input signal used in computing the gain control metric for a first duration when a large power swing in the gain control input signal is detected. | 11-11-2010 |
| 20100285744 | GAIN CONTROL METRIC COMPUTATION IN A WIRELESS REPEATER - A method for computing a gain control metric used in controlling gain in a wireless repeater operates to store correlation and normalization values associated with the gain control metric for the previous N samples in registers. For each new sample of the gain control input signal, the correlation and normalization values are computed by discarding the multiplication terms of the obsolete sample and adding the multiplication terms of the new sample to the stored correlation and normalization values. In this manner, the complexity of the computation is greatly reduced and the complexity of the computation does not increase with the integration length. | 11-11-2010 |
| 20100291865 | REPEATER COMMUNICATION USING INSERTED LOW POWER SEQUENCES - A method for providing repeater communication in a wireless repeater deployed in a multi-repeater environment includes inserting a message signal into the transmit signal of the repeater. The message signal may be a unique or quasi-unique low power spreading sequence uniquely identifying the repeater from other repeaters in the environment. The message signal may also contain information relating to the operational characteristics of the repeater. The message signal may be detected by another repeater or by an end-user wireless communication device. | 11-18-2010 |
| 20100303165 | PILOT TRANSMISSION AND CHANNEL ESTIMATION FOR AN OFDM SYSTEM WITH EXCESS DELAY SPREAD - Pilot transmission and channel estimation techniques for an OFDM system with excess delay spread are described. To mitigate the deleterious effects of excess delay spread, the number of pilot subbands is greater than the cyclic prefix length. This “oversampling” may be achieved by using more pilot subbands in each symbol period or different sets of pilot subbands in different symbol periods. In one example, a first set of pilot subands may be received in a first symbol period, and a second set of pilot subands may be received in a second symbol period. The first set of pilot subands and the second set of pilot subbands may be staggered in frequency. | 12-02-2010 |
| 20110026567 | SELF-INTERFERENCE CANCELLATION FOR MULTICHANNEL MODEMS - A method for detecting and reducing aliasing is described. The method may be implemented by a first wireless device. A first signal may be transmitted on a first frequency channel. A second signal may be received on a second frequency channel. The second signal may be received concurrently with the transmission of the first signal. Aliasing of the first signal on the second signal may be detected. Aliasing may be reduced. | 02-03-2011 |
| 20110064070 | FREQUENCY DIVISION MULTIPLE ACCESS SCHEMES FOR WIRELESS COMMUNICATION - Techniques for transmitting data using single-carrier frequency division multiple access (SC-FDMA) multiplexing schemes are described. In one aspect, data is sent on sets of adjacent subbands that are offset from one another to achieve frequency diversity. A terminal may be assigned a set of N adjacent subbands that is offset by less than N (e.g., N/2) subbands from another set of N adjacent subbands assigned to another terminal and would then observe interference on only subbands that overlap. In another aspect, a multi-carrier transmission symbol is generated with multi-carrier SC-FDMA. Multiple waveforms carrying modulation symbols in the time domain on multiple sets of subbands are generated. The multiple waveforms are pre-processed (e.g., cyclically delayed by different amounts) to obtain pre-processed waveforms, which are combined (e.g., added) to obtain a composite waveform. A cyclic prefix is appended to the composite waveform to generate the multi-carrier transmission symbol. | 03-17-2011 |
| 20110116392 | REMOVAL OF ICI/ISI ERRORS IN FREQUENCY DOMAIN CHANNEL ESTIMATION FOR WIRELESS REPEATERS - A method for estimating a feedback channel for a wireless repeater using frequency domain channel estimation estimates an error correction term using a most recent channel estimate and cancels the error correction term from a current block of the receive signal. Then, the feedback channel is estimated using frequency domain channel estimation and using a current block of the pilot signal and the corrected block of the receive signal. A channel estimate error term may also be estimated and subtracted directly from the channel estimate. | 05-19-2011 |
| 20110116531 | REMOVAL OF MULTIPLICATIVE ERRORS IN FREQUENCY DOMAIN CHANNEL ESTIMATION FOR WIRELESS REPEATERS - A method for estimating a feedback channel for a wireless repeater uses frequency domain channel estimation and uses a signal indicative of the amplified signal as a pilot signal. The channel estimation method generates a time domain feedback channel estimate from the frequency domain channel estimation and scales the time domain feedback channel estimate using scaling factors. In one embodiment, the scaling factors are function of a tap index and the block size of the frequency domain channel estimation. | 05-19-2011 |
