Abstract: Methods and apparatus for estimating time of arrival information associated with a wireless signal are disclosed. In an embodiment, a wireless device (102), or any other suitable device or system, determines a channel type based on multiple occurrences of a reference signal (700) (e.g., determine if a channel is delay-spread or non-delay-spread based on a ratio of largest peak to a mean of other peaks). The wireless device (102) then selects a time of arrival generator (800 or 900) based on the channel type (e.g., use delay-spread estimator if ratio is below threshold, and use non-delay-spread estimator if ratio is above threshold). The wireless device then (102) estimates the time of arrival information using the selected time of arrival generator (800 or 900) (e.g., sum peaks from multiple occasions and then estimate for delay-spread or estimate the time of arrival from each occasion and then average for non-delay-spread).

Abstract: A method and system generates channel response estimates by performing time direction filtering of first channel estimates obtained from frequency direction filtering. A baseband integrated circuit (BBIC) receives information signals comprising reference signals, control signals provided by physical control channels, and data signals provided by physical data channels. Using a latency requirement of a physical channel, symbol selection logic selects valid reference signal symbol positions corresponding to first channel estimates from among frequency filtered received reference signals. A coefficient set selection logic selects a set of filter coefficients from among multiple sets of pre-optimized coefficients, utilizing at least one of (a) the latency requirement, (b) a channel condition, and (c) the selected reference signal symbol positions.

Abstract: Methods and apparatus for estimating time of arrival information associated with a wireless signal are disclosed. In an embodiment, a wireless device (102), or any other suitable device or system, determines a channel type based on multiple occurrences of a reference signal (700) (e.g., determine if a channel is delay-spread or non-delay-spread based on a ratio of largest peak to a mean of other peaks). The wireless device (102) then selects a time of arrival generator (800 or 900) based on the channel type (e.g., use delay-spread estimator if ratio is below threshold, and use non-delay-spread estimator if ratio is above threshold). The wireless device then (102) estimates the time of arrival information using the selected time of arrival generator (800 or 900) (e.g., sum peaks from multiple occasions and then estimate for delay-spread or estimate the time of arrival from each occasion and then average for non-delay-spread).

Abstract: A noise thresholder of a baseband modem integrated circuit (BMIC) compares measured noise variances on corresponding receiver paths to a pre-established threshold minimum value. The noise thresholder assigns as a noise variance value for a corresponding receiver path either (a) a measured noise variance value for each receiver path having a measured noise variance that is larger than the pre-established threshold minimum, and (b) the pre-established threshold minimum value for each receiver path having a measured noise variance that is less than or equal to the pre-established threshold minimum value. A noise balancer performs noise balancing to provide a same signal to noise ratio (SNR) across all receiver paths, based on the assigned noise variances provided at the noise thresholder. A detection engine utilizes a lowest assigned noise variance value and outputs yielded by the noise balancer to simplify equalization computations while providing a high performance symbol detection capability.

Abstract: A noise thresholder of a baseband modem integrated circuit (BMIC) compares measured noise variances on corresponding receiver paths to a pre-established threshold minimum value. The noise thresholder assigns as a noise variance value for a corresponding receiver path either (a) a measured noise variance value for each receiver path having a measured noise variance that is larger than the pre-established threshold minimum, and (b) the pre-established threshold minimum value for each receiver path having a measured noise variance that is less than or equal to the pre-established threshold minimum value. A noise balancer performs noise balancing to provide a same signal to noise ratio (SNR) across all receiver paths, based on the assigned noise variances provided at the noise thresholder. A detection engine utilizes a lowest assigned noise variance value and outputs yielded by the noise balancer to simplify equalization computations while providing a high performance symbol detection capability.

Abstract: A method and system generates channel response estimates by performing time direction filtering of first channel estimates obtained from frequency direction filtering. A baseband integrated circuit (BBIC) receives information signals comprising reference signals, control signals provided by physical control channels, and data signals provided by physical data channels. Using a latency requirement of a physical channel, symbol selection logic selects valid reference signal symbol positions corresponding to first channel estimates from among frequency filtered received reference signals. A coefficient set selection logic selects a set of filter coefficients from among multiple sets of pre-optimized coefficients, utilizing at least one of (a) the latency requirement, (b) a channel condition, and (c) the selected reference signal symbol positions.

Abstract: Specifically, a method and system that performs MIMO and beamforming at a base station based on an uplink channel sounding (ULCS) from only one of the mobile station antennas and closed-loop multiple input, multiple output (MIMO) schemes based on the singular value decomposition (SVD) of the channel matrix. The ULCS is limited to sounding and the channel uses fewer than an optimal number of transmit antennas (e.g. one for WiMAX). The base station arrays may be configured for a full array transmitting mode or a sub-array transmitting mode.

Abstract: An orthogonal frequency division multiplexing wireless communication terminal, that communicates with a base unit, obtains a set of analog coefficients by transforming a transmit spatial covariance matrix, modulates the set of analog coefficients onto multiple channels to form a feedback waveform, and transmits the feedback waveform to the base unit.

Abstract: A receiver and methods of operation wherein Log-Likelihood-Ratio calculation are performed for arbitrary channel estimators with linear Minimum-Mean-Square-Error (MMSE) combining, successive cancellation combining, or joint detection. In some embodiments, the use of linear MMSE or successive cancellation combining may be employed to greatly lower the computational complexity over joint detection. In (401) a channel estimation MSE as a function of frequency, the transmitter modulation type, and a noise power are provided to the LLR component (313). A signal from a transmitter is received at one of the various antennas (301), (303) and respective receiver component (305), (307) in block (403). The channel estimation component (309) computes a channel estimate for the signal from the transmitter, or computes multiple channel estimates for multiple transmitter sources, in block (405).

Abstract: A generalized form of cyclic shift diversity is described for use in an OFDM system with multiple transmit antennas. Multiple cyclic shifts are performed for each transmit antenna and the shifted signals are scaled and summed to form a time-domain data stream for each transmit antenna. A cyclic extension is added to each data stream prior to transmission.

Abstract: Specifically, a method and system that performs MIMO and beamforming at a base station based on an uplink channel sounding (ULCS) from only one of the mobile station antennas and closed-loop multiple input, multiple output (MIMO) schemes based on the singular value decomposition (SVD) of the channel matrix. The ULCS is limited to sounding and the channel uses fewer than an optimal number of transmit antennas (e.g. one for WiMAX). The base station arrays may be configured for a full array transmitting mode or a sub-array transmitting mode.

Abstract: In an OFDM system the same Walsh code is used at the same time for a plurality of transmitters. The multiple transmitters can be from the same, or different devices (e.g., different base stations on the downlink, different terminals on the uplink). Each subcarrier/antenna combination will share a similar pilot Walsh code, except for the fact that the scrambled spread pilot signals will be phase shifted on some subcarriers of some antennas, based on the subcarrier/antenna combination.

Abstract: A method in an OFDM wireless user terminal that communicates with a base unit is disclosed. The method comprises computing a transmit spatial covariance matrix, transforming the spatial covariance matrix, and transmitting the transformed spatial covariance matrix to a base unit.

Abstract: A generalized form of cyclic shift diversity is described for use in an OFDM system with multiple transmit antennas. Multiple cyclic shifts are performed for each transmit antenna and the shifted signals are scaled and summed to form a time-domain data stream for each transmit antenna. A cyclic extension is added to each data stream prior to transmission.

Abstract: A receiver and methods of operation wherein Log-Likelihood-Ratio calculation are performed for arbitrary channel estimators with linear Minimum-Mean-Square-Error (MMSE) combining, successive cancellation combining, or joint detection. In some embodiments, the use of linear MMSE or successive cancellation combining may be employed to greatly lower the computational complexity over joint detection. In (401) a channel estimation MSE as a function of frequency, the transmitter modulation type, and a noise power are provided to the LLR component (313). A signal from a transmitter is received at one of the various antennas (301), (303) and respective receiver component (305), (307) in block (403). The channel estimation component (309) computes a channel estimate for the signal from the transmitter, or computes multiple channel estimates for multiple transmitter sources, in block (405).

Abstract: In an OFDM system the same Walsh code is used at the same time for a plurality of transmitters. The multiple transmitters can be from the same, or different devices (e.g., different base stations on the downlink, different terminals on the uplink). Each subcarrier/antenna combination will share a similar pilot Walsh code, except for the fact that the scrambled spread pilot signals will be phase shifted on some subcarriers of some antennas, based on the subcarrier/antenna combination.

Abstract: A staggered spread OFCDM scheme is utilized that improves channel estimation. In a first embodiment, each chip stream is time shifted by a predetermined amount and then transmitted on a predetermined subcarrier. This results in time-spread symbols being staggered (time-offset) on different subcarriers allowing for more frequent sampling of the channel. In a second embodiment a staggered spreading approach is applied in the frequency dimension to improve the performance of a system with spreading in the frequency dimension.

Abstract: A system for adaptively processing a telephonic speech signal performs modification in either the spectral domain or the time domain to bring the power in each frequency above the hearing threshold of the listener but below the upper limit of the listener's dynamic range.