Qualcomm Incorporated

Matthias Brehler

Brian Clarke Banister

Je Woo Kim

Jong Hyeon Park

Serguei A Glazko

Peter S Gaal

Tom Chin

Guangming Shi

Junqiang Li

Kapil Bhattad

Kuo-Chun Lee

Raghu Narayan Challa

Masato Kitazoe

Michael Lee McCloud

Jing Liu

Ju Won Park

Remi Jonathan Gurski

Joseph C Chan

Kurt William Otte

Tae Ryun Chang

Vincent Knowles Jones, Iv

Ayman Fawzy Naguib

Inyup Kang

Jon James Anderson

Vincent K Jones

Albert Van Zelst

Farrokh Abrishamkar

Arthur James Neufeld

James E Beckman

Shivratna Giri Srinivasan

Michael Leviant

Allert Van Zelst

Mahesh A Makhijani

Sunil Kumar Kandukuri Narayana

Bijan B Tuysserkani

John Charles May

Nagabhushan Kurapati

Kurt W Otte

Remi J Gurski

Certain aspects of the present disclosure provide techniques for wireless communications, wherein first number of transit antennas is advertised, but a different number of transmit antennas are actually used for transmission.

Energy saving mode with maintained number of advertised transmit antennas

Described herein are aspects related to communicating with a first radio access technology (RAT) and a second RAT, wherein a set of multi-input, multi-output (MIMO) resources is allocated for communication between a mobile station (MS) and a base station (BS) of the first RAT. A request message is sent to the BS of the first RAT requesting reallocation of at least a portion of the set of MIMO resources in a scan duration. During the scan duration, signals are received from a BS of the second RAT over a reallocated subset of the set of MIMO resources and communications occur with the BS of the first RAT over a non-reallocated subset of the set of MIMO resources. During a normal duration subsequent to the scan duration, communications occur with the BS of the first RAT using the set of MIMO resources including at least some of the reallocated subset of the set of MIMO resources.

Methods and systems for inter-RAT handover in multi-mode mobile station

Methods and apparatus for correcting frequency errors between a carrier frequency of a signal received by a wireless device and a reference frequency local to the device. For certain aspects, such a method generally includes receiving a signal in a receiver having an LO producing a reference frequency, a radio frequency (RF) phase-locked loop (PLL), and a digital rotator, estimating a frequency difference between a carrier frequency of the received signal and the LO reference frequency, and applying the estimated frequency difference to the RF PLL and the digital rotator.

Dual frequency tracking loop for OFDMA systems

A plurality of predetermined amplifier gain states for a low noise amplifier (LNA) are run during initial acquisition in a time division duplex (TDD) system. Acquisition of a received signal is determined based on searching across the plurality of predetermined amplifier gain states. Forcing the amplifier gain into a set of predetermined gain states affords quicker resolution of initial acquisition for setting the gain of the LNA, which in TDD systems is complicated due to an uncertain uplink/downlink timeline that precludes continuous operation of a gain setting algorithm run in the LNA.

Methods and apparatus for initial acquisition in a communication system

Providing for reduced complexity or improved accuracy in de-mapping received wireless data streams for multi-channel wireless communication is described herein. By way of example, a low-complexity likelihood algorithm can be employed to de-map data bits from the wireless data streams. In one particular example, the likelihood algorithm can approximate a received bit with a subset of received wireless symbols correlated the bit, reducing algorithm complexity. In other examples, a limited set of received wireless symbols can be employed for the subset, further reducing algorithm complexity. According to at least one other example, logarithmic terms of the algorithm can be approximated with non-logarithmic functions, such as a look-up table, series expansion, polynomial approximation, or the like. These approximations can enhance symbol de-mapping accuracy while maintaining or improving processing overhead for a wireless receiver.

Multi-term demapping for multi-channel wireless communication

Methods provided may generally include sending a BS of a first RAT a request message indicating a set of MIMO resources to reallocate; during a scan duration, communicating with the BS of the first RAT using non-reallocated MIMO resources and communicating with a BS of a second RAT using reallocated MIMO resources; and during a normal duration, communicating with the BS of the first RAT using the reallocated and non-reallocated MIMO resources. Apparatus provided may generally include logic for receiving a request message indicating a set of MIMO resources of the MS to reallocate; logic for, during a scan duration, communicating with the MS in a first transmission mode assuming the use of only non-reallocated MIMO resources by the MS; and logic for, during a normal duration, communicating with the MS in a second transmission mode assuming the use of the reallocated and non-reallocated MIMO resources by the MS.

Methods and systems for inter-rat handover in multi-mode mobile station

A method and apparatus for decoding of tailbiting convolutional codes (TBCC) are disclosed. The proposed modified maximum-likelihood TBCC decoding technique preserves error correction performance of optimal maximum-likelihood based TBCC decoding, while the computational complexity is substantially decreased since a reduced number of decoding states has been evaluated. Compare to other sub-optimal TBCC decoding algorithms, modified maximum-likelihood TBCC decoding achieves improved packet error rate performance with similar computational complexity.

Methods and systems for modified maximum-likelihood based TBCC decoding

Techniques for deriving a channel estimate using a scattered pilot and a continual pilot are described. The scattered pilot is sent on different sets of carriers in different symbol periods. The continual pilot is sent in each symbol period on irregularly spaced carriers. The scattered pilot is used to identify the indices of channel taps of interest, e.g., L strongest channel taps. The continual pilot is used to determine the complex gains of these L channel taps. A receiver derives a channel impulse response estimate based on received pilot symbols for the scattered pilot, identifies the L strongest channel taps, and determines the indices of these L strongest channel taps. The receiver forms a Fourier sub-matrix based on the L tap indices and determines the gains of the L channel taps based on received pilot symbols for the continual pilot and the Fourier sub-matrix.

Channel estimation for multi-carrier communication

Methods and apparatus are provided for increasing throughput in a wireless communication system by reducing the amount of overhead transmitted to certain user terminals. Overhead due to control information may be reduced for these certain user terminals by selecting a low repetition factor. Overhead may be further reduced for these certain user terminals by selecting a modulation/coding scheme with a higher data rate for transmitting the control information. The selection may be based on channel conditions associated with the user terminals, such as signal-to-interference-plus-noise ratios (SINRs).

Methods and systems for overhead reduction in a wireless communication network

Certain embodiments of the present disclosure provide a method for scanning for paging messages in a second radio access technology (RAT) network, such as a CDMA network, while connected to a first RAT network, such as a WiMAX network. For certain embodiments, an enhanced scanning request message may facilitate establishing a scanning cycle in the first RAT that aligns with a paging cycle of the second RAT.

Methods and systems for multi-mode terminal scanning

Systems and methodologies are described that facilitate signal separation across different carriers within a wireless communications environment. The systems and methods can identify a carrier spacing that can be based upon a tone spacing associated with two or more carriers. Such carrier spacing can be employed within a network in order to mitigate signal separation with multiple carriers. The subject innovation can further evaluate a carrier raster associated with a network in order to identify a carrier spacing to ensure orthogonality between tones from different carriers.

Interference reduction between OFDM carriers by frequency offset optimization

Certain embodiments of the present disclosure provide techniques for approximate computation of lnorms as a part of the maximum likelihood (ML) detection: tri-maxmin, maxsum and sortsum algorithms. The proposed approximation schemes show better accuracy than conventional approximation schemes&#x2014;the abssum and maxmin algorithms, while the computational complexity is very similar. The error rate performance of the ML detection that utilizes proposed norm-approximation techniques are very close to the reference ML detection with exact calculation of lnorms, while the computational complexity is significantly smaller.

Methods and systems using norm approximation for maximum likelihood MIMO decoding

Techniques proposed in the present disclosure may used to update an FFT window position and perform linear phase compensation for OFDM wireless systems with up to two antennas at the receiver. Techniques presented herein may help resolve a problem of determining an optimum FFT window position under the condition that the length of channel impulse response is larger than the length of cyclic prefix.

Methods and systems for time tracking in OFDM systems

For signaling detection using an adaptive threshold, the channel condition observed by a signaling bit (e.g., a paging indicator bit) is estimated (e.g., by a pilot strength estimate). A metric for the signaling bit is computed based on recovered symbols for the signaling bit and the estimated channel condition. An adaptive threshold is selected based on the estimated channel condition. A decision is derived for the signaling bit based on the metric, the adaptive threshold, and the estimated channel condition. Multiple threshold values may be derived for the adaptive threshold for multiple ranges of estimated channel condition, one threshold value for each range. A look-up table stores the threshold values and provides the proper adaptive threshold value for any given estimated channel condition.

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Boulder, CO, United States of America

Matthias Brehler