Abstract: Techniques to process data for transmission in a time division duplexed (TDD) communication system. In one aspect, the frequency response of a forward link is estimated at a base station based on reverse link transmissions (e.g., pilots) from a terminal. Prior to a data transmission on the forward link, the base station determines a reverse transfer function based on the pilots transmitted by the terminal, “calibrates” the reverse transfer function with a calibration function to derive an estimate of a forward transfer function, and preconditions modulation symbols based on weights derived from the forward transfer function. In another aspect, the terminal estimates the “quality” of the forward link and provides this information to the base station. The base station then uses the information to properly code and modulate data prior to transmission such that the transmitted data can be received by the terminal at the desired level of performance.

Abstract: A decision feedback equalizer includes a chip estimate buffer that forms chip estimates into a vector. A CCK decoder decodes the vector of chip estimates, and a CCK encoder, connected with the CCK decoder, re-encodes the vector of chip estimates into a valid CCK code word. At the same time, a chip slicer provides direct sliced chips from the chip estimates. An update module then forms a hybrid vector from the valid CCK code-word and the direct sliced chips for input to the feedback filter of the decision feedback equalizer. The hybrid feedback filter input vector reflects the CCK coding gain of its re-encoded portion thereby reducing the estimated chip error rate to improve the performance of the decision feedback equalizer.

Abstract: An uplink channel response matrix is obtained for each terminal and decomposed to obtain a steering vector used by the terminal to transmit on the uplink. An “effective” uplink channel response vector is formed for each terminal based on its steering vector and its channel response matrix. Multiple sets of terminals are evaluated based on their effective channel response vectors to determine the best set (e.g., with highest overall throughput) for uplink transmission. Each selected terminal performs spatial processing on its data symbol stream with its steering vector and transmits its spatially processed data symbol stream to an access point. The multiple selected terminals simultaneously transmit their data symbol streams via their respective MIMO channels to the access point. The access point performs receiver spatial processing on its received symbol streams in accordance with a receiver spatial processing technique to recover the data symbol streams transmitted by the selected terminals.

Abstract: An uplink channel response matrix is obtained for each terminal and decomposed to obtain a steering vector used by the terminal to transmit on the uplink. An “effective” uplink channel response vector is formed for each terminal based on its steering vector and its channel response matrix. Multiple sets of terminals are evaluated based on their effective channel response vectors to determine the best set (e.g., with highest overall throughput) for uplink transmission. Each selected terminal performs spatial processing on its data symbol stream with its steering vector and transmits its spatially processed data symbol stream to an access point. The multiple selected terminals simultaneously transmit their data symbol streams via their respective MIMO channels to the access point. The access point performs receiver spatial processing on its received symbol streams in accordance with a receiver spatial processing technique to recover the data symbol streams transmitted by the selected terminals.

Abstract: An uplink channel response matrix is obtained for each terminal and decomposed to obtain a steering vector used by the terminal to transmit on the uplink. An “effective” uplink channel response vector is formed for each terminal based on its steering vector and its channel response matrix. Multiple sets of terminals are evaluated based on their effective channel response vectors to determine the best set (e.g., with highest overall throughput) for uplink transmission. Each selected terminal performs spatial processing on its data symbol stream with its steering vector and transmits its spatially processed data symbol stream to an access point. The multiple selected terminals simultaneously transmit their data symbol streams via their respective MIMO channels to the access point. The access point performs receiver spatial processing on its received symbol streams in accordance with a receiver spatial processing technique to recover the data symbol streams transmitted by the selected terminals.

Abstract: Techniques for performing equalization of multiple signals received by a terminal in soft handoff with multiple base stations. The received signal at the terminal is conditioned and digitized to provide a stream of received samples, which is then equalized/filtered with multiple sets of coefficients to provide multiple streams of transmit chip estimates. One set of coefficients is provided for each base station and is used to provide a corresponding stream of transmit chip estimates. The multiple streams of transmit chip estimates are further processed to provide multiple streams of data symbol estimates, one stream of data symbol estimates for each base station. The multiple streams of data symbol estimates are then scaled with multiple scaling factors and combined to provide a stream of combined data symbol estimates. The processing for the multiple base stations may be performed by a single hardware unit in a time division multiplexed manner.

Abstract: Pilot transmission schemes suitable for use in wireless multi-carrier (e.g., OFDM) communication systems. These pilot transmission schemes may utilize frequency, time, or both frequency and time orthogonality to achieve orthogonality among the pilots transmitted by multiple base stations on the downlink. Frequency orthogonality is achieved by transmitting pilots on disjoint sets of subbands. Time orthogonality is achieved by transmitting pilots using different orthogonal codes (e.g., Walsh codes). The pilots may also be scrambled with different scrambling codes, which are used to randomize pilot interference and to enable identification of the transmitters of these pilots. Pilot interference cancellation may be performed to improve performance since subbands used for data transmission by one transmitter may also be used for pilot transmission by another transmitter. Pilot interference is estimated and then subtracted from received symbols to obtain pilot-canceled symbols having improved quality.

Abstract: A system and method for Interference Cancellation (IC). One aspect relates to iterative interference cancellation with iterative finger delay adaptation. The interference cancellation method comprises receiving multi-paths of a signal; and performing iterative interference cancellation to remove multi-path interference, wherein the performing iterative IC comprises estimating a Signal-to-Interference-plus-Noise Ratio (SINR) at each of a plurality of pre-determined rake receiver finger delays, and performing successive Channel Estimation (CE) and IC on rake receiver fingers according to their estimated SINRs, and wherein the CE of a next finger does not start until interference of a previous finger is removed from a sample buffer. The method may further comprise improving estimated rake receiver finger delay, and each iteration decreases the amount of interference observed by each finger.

Abstract: Method and apparatus to compute the combiner coefficients for wireless communication systems using an adaptive algorithm. One embodiment trains the weights on a signal known a priori that is time multiplexed with other signals, such as a pilot signal in a High Data Rate, HDR, system, wherein the signal is transmitted at full power. The adaptive algorithm recursively computes the weights during the pilot interval and applies the weights generated to the traffic signals. In one embodiment, the algorithm is a recursive least squares algorithm employing a transversal filter and weight calculation unit.

Abstract: A method and system for reverse link interference cancellation. One method comprises demodulating and decoding at least one signal sent from at least one access terminal and received by a first base station, sending demodulated, decoded information of the signal to a second base station, reconstructing the signal at the second base station, and subtracting the reconstructed signal from a buffer at the second base station.

Abstract: A carrier recovery method and apparatus using multiple stages of carrier frequency recovery are disclosed. A receiver uses multiple frequency generation sources to generate carrier signals used to downconvert a received signal. An analog frequency reference having a wide frequency range and coarse frequency resolution is used in conjunction with a digital frequency reference having a narrow frequency range and fine frequency resolution. The multiple carrier signals are multiplied by a received signal to effect a multi-stage downconversion, resulting in a baseband signal. A frequency tracking module measures the residual frequency error present in the baseband signal. The measured residual frequency error is then used to adjust the frequencies of the carrier signals generated by the multiple frequency generation sources.

Abstract: Embodiments disclosed herein relate to providing effective interference control in a wireless communication system. In one embodiment, a method for determining an interference level in a wireless communication system is described, including: determining a rise-over-thermal (RoT) metric based on an RoT received at each receiver antenna of an access network, the RoT relating to a ratio of a total energy to a thermal energy received at each receiver antenna; determining an interference-reduction factor (?) in relation to an interference energy reduced from the total energy received at each receiver antenna; and determining an effective rise-over-thermal (RoTeff) based on the RoT metric and the interference-reduction factor, the RoTeff relating to the interference level in the wireless communication system. The method may further include comparing the RoTeff with a threshold and relating the result of the comparison (e.g.

Abstract: In a CDMA data communication system capable of variable rate data transmission, a time-division power assignment cyclically reduces the carrier power level to at least one sector to reduce interference in neighboring sectors. The base station determines a time-division power assignment for each sector and generates signals according to the power assignment. The mobile unit generates filter coefficients corresponding to each power level. The mobile unit estimates Carrier Signal-to-Interference (C/I) to determine a data rate for each power level. Previous iterations of the equalizer are stored and used to refine future estimates.

Abstract: A carrier recovery method and apparatus using multiple stages of carrier frequency recovery are disclosed. A receiver uses multiple frequency generation sources to generate carrier signals used to downconvert a received signal. An analog frequency reference having a wide frequency range and coarse frequency resolution is used in conjunction with a digital frequency reference having a narrow frequency range and fine frequency resolution. The multiple carrier signals are multiplied by a received signal to effect a multi-stage downconversion, resulting in a baseband signal. A frequency tracking module measures the residual frequency error present in the baseband signal. The measured residual frequency error is then used to adjust the frequencies of the carrier signals generated by the multiple frequency generation sources.

Abstract: A method and system for interference cancellation (IC). One aspect relates to traffic interference cancellation. Another aspect relates to joint IC for pilot, overhead and data. Another aspect relates to improved channel estimation. Another aspect relates to adaptation of transmit subchannel gains.

Abstract: A method and system for interference cancellation (IC). One aspect relates to traffic interference cancellation. Another aspect relates to joint IC for pilot, overhead and data. Another aspect relates to improved channel estimation. Another aspect relates to adaptation of transmit subchannel gains.

Abstract: A method and system for interference cancellation (IC). One aspect relates to traffic interference cancellation. Another aspect relates to joint IC for pilot, overhead and data. Another aspect relates to improved channel estimation. Another aspect relates to adaptation of transmit subchannel gains.

Abstract: A method and system for interference cancellation (IC). One aspect relates to traffic interference cancellation. Another aspect relates to joint IC for pilot, overhead and data. Another aspect relates to improved channel estimation. Another aspect relates to adaptation of transmit subchannel gains.

Abstract: Method and apparatus to compute the combiner coefficients for wireless communication systems for a space-time solution. One embodiment trains the weights on a signal known a priori that is time multiplexed with other signals, such as a pilot signal in a High Data Rate, HDR, system, wherein the signal is transmitted at full power. A Minimizing Mean Square Error, MMSE, approach is applied allowing weight combining on a per path basis. The weights are calculated as a function of a noise correlation matrix and spatial signature per path. The noise correlation matrix is determined from an autocorrelation matrix of the received signal. In one embodiment, the MMSE approach is applied to a non-time gated pilot signal.

Abstract: Techniques to process data for transmission in a time division duplexed (TDD) communication system. In one aspect, the frequency response of a forward link is estimated at a base station based on reverse link transmissions (e.g., pilots) from a terminal. Prior to a data transmission on the forward link, the base station determines a reverse transfer function based on the pilots transmitted by the terminal, “calibrates” the reverse transfer function with a calibration function to derive an estimate of a forward transfer function, and preconditions modulation symbols based on weights derived from the forward transfer function. In another aspect, the terminal estimates the “quality” of the forward link and provides this information to the base station. The base station then uses the information to properly code and modulate data prior to transmission such that the transmitted data can be received by the terminal at the desired level of performance.