Qualcomm Incorporated

Agere Systems Inc.

Lsi Corporation

Mosaid Technologies Corporation

Conversant Intellectual Property Management Incorporated

Agere Systems Guardian Corp.

Airgo Networks, Inc.

D J Richard Van Nee

Vincent Knowles Jones, Iv

James M Gardner

Vincent K Jones

Geert Arnout Awater

Albert Van Zelst

Gregory C Steele

Greet Arnout Awater

Allert Van Zelst

Brian L Wong

Partho Pratim Mishra

Adriaan Kamerman

Wilhelmus Diepstraten

Kai Roland Kriedte

Arnold Liu

Geert Amout Awater

An OFDM system uses a normal mode which has a symbol length T, a guard time TG and a set of N sub-carriers, which are orthogonal over the time T, and one or more fallback modes which have symbol lengths KT and guard times KTG where K is an integer greater than unity. The same set of N sub-carriers is used for the fallback modes as for the normal mode. Since the same set of sub-carriers is used, the overall bandwidth is substantially constant, so alias filtering does not need to be adaptive. The Fourier transform operations are the same as for the normal mode. Thus fallback modes are provided with little hardware cost. In the fallback modes the increased guard time provides better delay spread tolerance and the increased symbol length provides improved signal to noise performance, and thus increased range, at the cost of reduced data rate.

Frequency division multiplexing system with selectable rate

Systems and methodologies are described for processing information at a device operating in a wireless communication system. Techniques for in-phase and quadrature (I/Q) calibration, interference cancellation, channel estimation, and signal-to-noise ratio (SNR) and rank metric calculation are provided herein. As provided herein, one or more of the described techniques can be used to adjust the performance of a wireless station in the presence of impairments to the wireless station and/or a communication link used by the wireless station.

High performance station

A MIMO transmitter including an interleaving system for parsing encoded bits to a plurality of spatial streams and a plurality of interleavers to interleave bits for spatial streams such that at least a first spatial stream uses a first stream interleaver that interleaves with a pattern distinct from a second stream interleaver interleaving for a second spatial stream.

Advanced MIMO interleaving

Methods and systems for signaling on a mixed-mode wireless network comprising a plurality of channels are provided. The mixed-mode wireless network includes high-throughput (HT) wireless devices and legacy wireless devices that use channels of the same width. The HT devices transmit data on at least two channels, while the legacy devices transmit on one channel. The distances between the HT channels and the distances between the legacy channels might differ, however, the channels used by the HT devices and the legacy devices may overlap. As a result, cooperation between the HT devices and legacy devices is provided to enable the devices to coexist on the same wireless network by minimizing collisions and interference. The HT devices are configured to send control information to the legacy devices to coordinate transmission by the HT devices with the legacy devices.

Advanced wireless packet transmission scheme with enhancements to accommodate basic wireless packet transmission scheme

A modified preamble is used by extended devices that operate at higher rates, MIMO or other extensions relative to strict 802.11a-compliant devices. The extended devices might use multiple antenna techniques (MIMO), where multiple data streams are multiplexed spatially and/or multi-channel techniques, where an extended transmitter transmits using more than one 802.11a channel at a time. Such extensions to IEEE 802.11a can exist in extended devices. The modified preamble is usable for signaling, to legacy devices as well as extended devices, to indicate capabilities and to cause legacy devices or extended devices to defer to other devices such that the common communication channel is not subject to unnecessary interference. The modified preamble is also usable for obtaining MIMO channel estimates and/or multi-channel estimates. The modified preamble preferably includes properties that facilitate detection of conventional and/or extended modes ('mode detection') and provides some level of coexistence with legacy IEEE 802.11a devices.

Modified preamble structure for IEEE 802.11A extensions to allow for coexistence and interoperability between 802.11A devices and higher data rate, MIMO or otherwise extended devices

A modified preamble is used by extended devices that operate at higher rates, MIMO or other extensions relative to strict 802.11a-compliant devices. The extended devices might use multiple antenna techniques (MIMO), where multiple data streams are multiplexed spatially and/or multi-channel techniques, where an extended transmitter transmits using more than one 802.11 a channel at a time. Such extensions to IEEE 802.11 a can exist in extended devices. The modified preamble is usable for signaling, to legacy devices as well as extended devices, to indicate capabilities and to cause legacy devices or extended devices to defer to other devices such that the common communication channel is not subject to unnecessary interference. The modified preamble is also usable for obtaining MIMO channel estimates and/or multi-channel estimates. The modified preamble preferably includes properties that facilitate detection of conventional and/or extended modes ('mode detection') and provides some level of coexistence with legacy IEEE 802.11 a devices.

A digital modulation system provides enhanced multipath performance by using modified orthogonal codes with reduced autocorrelation sidelobes while maintaining the cross-correlation properties of the modified codes. For example, the modified orthogonal codes can reduce the autocorrelation level so as not to exceed one-half the length of the modified orthogonal code. In certain embodiments, an M-ary orthogonal keying (MOK) system is used which modifies orthogonal Walsh codes using a complementary code to improve the auto-correlation properties of the Walsh codes, thereby enhancing the multipath performance of the MOK system while maintaining the orthogonality and low cross-correlation characteristics of the Walsh codes.

M-ary orthogonal keying system

Systems and methodologies are described that provide low-complexity soft-output detection for MIMO communication systems. Looping can be performed over a set of constellation points per spatial stream to obtain distance metrics for each of a series of transmitted streams, for which values for the other transmitted streams can be estimated using a MIMO channel matrix and a sub-optimal MIMO algorithm. Examples of MIMO algorithms that can be utilized include Per-Stream List Detection (PSLD), Lattice-Reduced Detection (LRD), and a Guided-M Algorithm. Performance can be further improved by pre-processing the MIMO channel matrix and/or by utilizing techniques for Enhanced Metric Usage (EMU).

Near soft-output maximum-likelihood detection for multiple-input multiple-output systems

In one embodiment, a wireless device for a wireless data communication system including the wireless device and a base station. The base station includes a plurality of first groups and a signal-processing unit. Each first group includes a receiver and at least one antenna connected to the receiver. The signal-processing unit includes memory and a processor adapted to process signals received by the first groups using a Maximum Likelihood Detection (MLD) method. The wireless device includes a plurality of second groups, each second group adapted to transmit a wireless signal to at least one first group via a corresponding communication channel. Each second group further includes a transmitter and at least one antenna connected to the transmitter. The signal-processing unit is adapted to store, in the memory, information corresponding to one or more transfer functions, each transfer function corresponding to transmission of a wireless signal from an antenna of the second groups to an antenna of the first groups. The transmitters and receivers are adapted to operate at essentially the same frequency or frequency band. Two or more of the communication channels are generated simultaneously. Each transmitter is adapted to modulate an information signal on a radio-frequency signal according to a Quadrature Amplitude Modulation (QAM) method to transmit QAM symbols. Each receiver is adapted to demodulate information signals from a received radio-frequency signal according to the QAM method.

Decoding techniques for multi-antenna systems

Methods and systems are provided for transmitting a plurality of information signals in a multiple antenna communication system. One or more information signals are coded using a plurality of coders to generate the plurality of coded information signals and an Inverse Fast Fourier Transformation is performed on each of the plurality of coded information signals to create a corresponding output signal. Each of the corresponding output signals are transmitted on a different antenna. Each of the plurality of coded information signals can optionally be separated into K signals. On the receiver side, a signal comprising K different frequencies is received on at least N receive antennas and a Fast Fourier Transformation is applied to each of the at least N received versions of the signal comprising K different frequencies to generate N*K low frequency signals. The N*K separate low frequency signals are then combined to recover a transmitted information signal, based on one or more transfer functions from each of a plurality of transmit antennas to each of the N receive antennas.

Methods and systems for transmitting an information signal in a multiple antenna communication system

Improved beamforming techniques are provided for use in MIMO (multiple-input, multiple-output) communication systems, including MIMO-OFDM systems. The techniques include: (1) determining beamforming (BF) weights using a smoothed singular value decomposition (SVD) of the channel matrix; (2) determining BF weights using a power-optimized minimum mean-square error (MMSE) technique when the number of available transmit antennas exceeds the number of signal streams; and (3) determining BF weights using a hybrid SVD-MMSE technique. Additional techniques for reducing the impulse response length of the BF weights and/or normalizing the power per transmit antenna or per data stream may be used in conjunction with these or other beamforming techniques.

Growing community of inventors

De Meern, Netherlands

D J Richard Van Nee