Motorola Corporation

Motorola Mobility LLC

Thomson Licensing

Google Inc.

Thomas Peter Krauss

Kumar Ramaswamy

Kevin Lynn Baum

Timothy Forrest Settle

Vijay Nangia

Frederick W Vook

Xiangyang Zhuang

Timothy A Thomas

Anthony R Schooler

Bryan S Nollett

Krishna Kamal Sayana

Bishwarup Mondal

Michael J Carney

Fan Wang

William J Hillery

Bryan W Zancho

David L Steckl

Sandeep Mukthavaram

Methods and apparatus for estimating time of arrival information associated with a wireless signal are disclosed. In an embodiment, a wireless device (), or any other suitable device or system, determines a channel type based on multiple occurrences of a reference signal () (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 () then selects a time of arrival generator (or) 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 () estimates the time of arrival information using the selected time of arrival generator (or) (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).

Methods and apparatus for estimating time of arrival information associated with a wireless signal

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. A time direction filter uses the selected filter coefficients to filter the first channel estimates in order to generate a channel response estimate for a resource element of the physical channel.

Flexible low complexity reference signal filtering for LTE receivers

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.

Noise power thresholding and balancing for long term evolution (LTE) symbol detection

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.

System and method for combination multiple input, multiple output (MIMO) and beamforming

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.

Closed-loop transmission feedback in wireless communication systems

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 () a channel estimation MSE as a function of frequency, the transmitter modulation type, and a noise power are provided to the LLR component (). A signal from a transmitter is received at one of the various antennas (), () and respective receiver component (), () in block (). The channel estimation component () computes a channel estimate for the signal from the transmitter, or computes multiple channel estimates for multiple transmitter sources, in block (). In block (), decoder inputs are determined as a function of the channel estimates, the received signal, noise power, and channel estimation MSE.

Receiver having multi-antenna log likelihood ratio generation with channel estimation error

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.

Method and apparatus for finite impulse response cyclic-shift diversity

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.

Method and apparatus for transmission and reception within an OFDM communication system

A hierarchical QAM system allows the transmission of different sources by embedding the relative constellation points. A QAM transmitting system, includes a source of a level 1 and a level 2 data stream, each data stream carrying successive symbols. A hierarchical QAM transmitter, coupled to the level 1 and level 2 data stream source, generates a hierarchical QAM signal in which a level 1 symbol is represented by a data point in one of four quadrants in the I-Q plane, and a level 2 symbol is represented by the data point in one of four sub-quadrants surrounding a center point of the quadrant containing the level 1 data point. The level 2 data point is spaced away from the center point by a grouping factor set to more closely match the bit error rate performance of the level 1 and level 2 data streams.

Hierarchical QAM transmission system with varying grouping factor

A OAM receiver includes a source of a received hierarchical OAM signal. The hierarchical OAM signal represents successive data points in the I-Q plane, each data point being in one of four quadrants. Circuitry, coupled to the hierarchical OAM signal source, calculates the location in the I-Q plane of the center-of-gravity of successive received data points in a quadrant. A level 1 decoder is responsive to a received data point and detects the quadrant in the I-Q plane of a received data point. Further circuitry, coupled to the hierarchical OAM signal source and responsive to the calculating circuitry, translates the received data point in the I-Q plane such that the center-of-gravity of the detected quadrant is translated to the origin of the I-Q plane. A level 2 decoder is then responsive to the translated data point for detecting the quadrant of the translated data point.

Center of gravity control for hierarchical QAM transmission systems

A hierarchical QAM system allows the transmission of different sources by embedding the relative constellation points. At the transmitter the constellations generated by the different sources are remapped by a grey coder and then combined. At the receiver, the different source data are decoded by using a corresponding grey code demapper.

Gray encoding for hierarchical QAM transmission systems

The power of the respective codes used by the first and second error detection/correction circuitry are such that the coded bit error rate of the first data stream is more closely matched to the coded bit error rate of the second data stream. A hierarchical QAM system allows the transmission of different sources by embedding the relative constellation points. The hierarchical QAM transmitter encodes the first data stream using a code having a first detection/correction power and encodes the second data stream using a code having a second detection/correction power.

Error detection/correction coding for hierarchical QAM transmission systems

A method for detecting a presence of an excess delay spread within a received signal is provided. First, a quantitative estimation of a similarity of two segments of the received signal is performed. Thereafter, the presence of the excess delay spread within the received signal based upon the quantitative estimation is determined. In determining the presence of an excess delay spread, the quantitative estimation can be compared to a detection threshold.

Excess delay spread detection method for multi-carrier communication systems

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.

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Algonquin, IL, United States of America

Thomas Peter Krauss