Agere Systems Inc.

Qualcomm Incorporated

Avago Technologies General IP (singapore) Pte. Ltd.

Interuniversitair Microelektronica Centrum (imec)

Avago Technologies General IP Pte, Ltd.

Allert Van Zelst

Tim Schenk

Vincent K Jones

D J Richard Van Nee

Adriaan Kamerman

Jan Boer

Bas Driesen

Xiao-Jiao Tao

Isabella Modonesi

Vincent Knowles Jones, Iv

Brian Clarke Banister

Francky Catthoor

Jong Hyeon Park

Je Woo Kim

Matthias Brehler

Robert John Kopmeiners

Kai Roland Kriedte

Arnout Vandecappelle

Tycho Van Meeuwen

Jan H Boer

A method and apparatus are provided for transmitting one or more symbols in a multiple antenna wireless communication system. Subcarriers from one or more symbols are interleaved across a plurality of antennas. The symbols may be, for example, long or short training symbols based on a single-antenna long or short training symbol, respectively, and wherein each subsequent subcarrier from the single-antenna training symbol is positioned in a training symbol for a logically adjacent antenna. One or more additional subcarriers may be inserted in at least one of the plurality of symbols to allow nulled subcarriers to be estimated using an interpolation-based channel estimation technique. The remaining portions of a header, as well as the data sequences of a packet, may also be diagonally loaded.

Method and apparatus for communicating symbols in a multiple input multiple output communication system using interleaved subcarriers across a plurality of antennas

A 'post-squaring' detection algorithm, and related devices, that may reduce the complexity of maximum likelihood detection (MLD) schemes while preserving their performance is provided. Rather than search for optimum metrics (such as minimum distance metrics) based on squared norm values, a search may be based on un-squared norm metrics, and the squaring may be postponed, for example, until subsequent log-likelihood ratio (LLR) computation. For certain embodiments, approximations of un-squared norm values may significantly reduce computation complexity.

Methods and systems for maximum-likelihood detection using post-squaring compensation

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.

Beamforming techniques for MIMO communication systems

A method and apparatus are disclosed for transmitting symbols in a multiple antenna wireless communication system, such that the symbols can be interpreted by a lower order receiver (i.e., a receiver having a fewer number of antennas than the transmitter). For example, subcarriers from one or more symbols can be transmitted such that each of the subcarriers are active on only one of the antennas at a given time. In one implementation, the subcarriers are diagonally loaded across logically adjacent antennas. The symbols can include one or more long training symbols and optionally a SIGNAL field that indicates a duration that a receiver should defer until a subsequent transmission. In this manner, a transmitter in accordance with the present invention may be backwards compatible with a lower order receiver and a lower order receiver can interpret the transmitted symbols or defer for an appropriate duration.

Methods and apparatus for backwards compatible communication in a multiple input multiple output communication system with lower order receivers

A method and apparatus are disclosed for transmitting symbols in a multiple antenna communication system according to a frame structure, such that the symbols can be interpreted by a lower order receiver (i.e., a receiver having a fewer number of antennas than the transmitter). The disclosed frame structure comprises a legacy preamble having at least one long training symbol and N-1 additional long training symbols that are transmitted on each of N transmit antennas. The legacy preamble may be, for example, an 802.11 a/g preamble that includes at least one short training symbol, at least one long training symbol and at least one SIGNAL field. A sequence of each of the long training symbols on each of the N transmit antennas are time orthogonal. The long training symbols can be time orthogonal by introducing a phase shift to each of long training symbols relative to one another.

Methods and apparatus for backwards compatible communication in a multiple antenna communication system using time orthogonal symbols

In a multiple-input, multiple-output (MIMO) system, a receiver is implemented with at least one additional receive path beyond the number of transmit antennas used to transmit the signals (e.g., wireless OFDM signals) received at the receiver. In one embodiment, the additional receive path is used to reduced co-channel interference (CCI) in the recovered OFDM signals. In particular, each receive path applies recursive filtering to generate separate subcarrier signals. A processor converts the separate subcarrier signals from the different receive paths into a first set of subcarrier signals corresponding to each transmitted OFDM signal, where each first set of subcarrier signals has desired signal and possibly CCI. The processor also generates a second set of subcarrier signals corresponding to the CCI. The processor subtracts portions of the second set of subcarrier signals from each first set of subcarrier signals to generate recovered OFDM signals having reduced CCI.

MIMO receivers having one or more additional receive paths

Symbol timing for a wireless communication system, such as a multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) wireless LAN system, is determined by summing the powers for an appropriate set of channel impulse responses, integrating this power summation over an appropriate window (e.g., equivalent to the guard interval), and identifying the time at which the maximum integration occurs. Depending on the implementation, symbol timing can be determined for each receiver branch individually or for all receiver branches jointly. In either case, the determined symbol timing(s) can minimize the amount of inter-symbol and inter-channel interferences that are invoked in the system.

Symbol timing for MIMO OFDM and other wireless communication systems

A system and method are provided that include determining optimum memory organization in an electronic device, wherein further determined are optimum resource interconnection patterns. One aspect of the system and method includes determining resource, e.g., memories and data paths, interconnection patterns of complex bus structures with switches using system-level information about the data-transfer conflicts. The quantity of memories within an electronic device, the size of the memories and the interconnection between the memories, including the interconnection of the memories with one or more data paths, defines a memory organization of an electronic device. Another aspect of the system and method relates to selecting an optimized memory organization, including selecting an optimized interconnection pattern between the memories and between the memories and the data paths.

Resource interconnection patterns in a customized memory organization context

Growing community of inventors

Woerden, Netherlands

Allert Van Zelst