Qualcomm Incorporated

Raytheon Company

Archer Daniels Midland Company

Steven J Howard

Mark S Wallace

John Wendell Ketchum

J Rodney Walton

Jay Rodney Walton

Jay Rod Walton

Fuyun Ling

Lizhong Zheng

James Arthur Proctor, Jr

Gwendolyn Denise Barriac

Dhananjay Ashok Gore

Kenneth Marvin Gainey

Hakan Inanoglu

Edward George Tiedemann, Jr

John Edward Smee

J Rodney Walton, Jr

Sanjiv Nanda

Charles E Wheatley, Iii

Michael Mao Wang

Tao Tian

Murali Paravath Menon

Bjorn Bjerke

Peter Monsen

J Rod Walton

Stein Arne Lundby

Irina Medvedev

Shravan K Surineni

Tadeusz Jarosinski

Rod J Walton

Gregary B Prince

Thomas E Gardiner

Irena Medvedev

Christopher S Joines

Alexandra J Sanborn

A system and method for transmitting packets from a transceiver to a repeater in the presence of relative motion between the transceiver and the repeater. In some embodiments, the method includes: adjusting a plurality of transmission times; transmitting each of a plurality of packets, at a respective adjusted transmission time, from the transceiver to the repeater; and retransmitting, by the repeater, each of the packets, at a respective retransmission time, each of the retransmission times being, as a result of the adjusting, more nearly the same as it would have been, in the absence of: the relative motion, and the adjusting.

System and method for mitigating platform motion in a communications system

Spatial spreading is performed in a multi-antenna system to randomize an 'effective' channel observed by a receiving entity for each transmitted data symbol block. For a MIMO system, at a transmitting entity, data is processed (e.g., encoded, interleaved, and modulated) to obtain Ndata symbol blocks to be transmitted in Ntransmission spans, where N&#x2265;1 and N&#x3e;1. The Nblocks are partitioned into Ndata symbol subblocks, one subblock for each transmission span. A steering matrix is selected (e.g., in a deterministic or pseudo-random manner from among a set of L steering matrices, where L&#x3e;1) for each subblock. Each data symbol subblock is spatially processed with the steering matrix selected for that subblock to obtain transmit symbols, which are further processed and transmitted via Ntransmit antennas in one transmission span. The Ndata symbol blocks are thus spatially processed with Nsteering matrices and observe an ensemble of channels.

Spatial spreading in a multi-antenna communication system

Pilots suitable for use in MIMO systems and capable of supporting various functions are described. The various types of pilot include&#x2014;a beacon pilot, a MIMO pilot, a steered reference or steered pilot, and a carrier pilot. The beacon pilot is transmitted from all transmit antennas and may be used for timing and frequency acquisition. The MIMO pilot is transmitted from all transmit antennas but is covered with different orthogonal codes assigned to the transmit antennas. The MIMO pilot may be used for channel estimation. The steered reference is transmitted on specific eigenmodes of a MIMO channel and is user terminal specific. The steered reference may be used for channel estimation. The carrier pilot may be transmitted on designated subbands/antennas and may be used for phase tracking of a carrier signal. Various pilot transmission schemes may be devised based on different combinations of these various types of pilot.

Pilots for MIMO communication systems

An uplink channel response matrix is obtained for each terminal and decomposed to obtain a steering vector used by the terminal to transmit on the uplink. An 'effective' uplink channel response vector is formed for each terminal based on its steering vector and its channel response matrix. Multiple sets of terminals are evaluated based on their effective channel response vectors to determine the best set (e.g., with highest overall throughput) for uplink transmission. Each selected terminal performs spatial processing on its data symbol stream with its steering vector and transmits its spatially processed data symbol stream to an access point. The multiple selected terminals simultaneously transmit their data symbol streams via their respective MIMO channels to the access point. The access point performs receiver spatial processing on its received symbol streams in accordance with a receiver spatial processing technique to recover the data symbol streams transmitted by the selected terminals.

Multi-antenna transmission for spatial division multiple access

Spatial spreading is performed in a multi-antenna system to randomize an 'effective' channel observed by a receiving entity for each transmitted data symbol block. For a MIMO system, at a transmitting entity, data is processed (e.g., encoded, interleaved, and modulated) to obtain Ndata symbol blocks to be transmitted in Ntransmission spans, where N&#x2267;1 and N&#x3e;1. The Nblocks are partitioned into Ndata symbol subblocks, one subblock for each transmission span. A steering matrix is selected (e.g., in a deterministic or pseudo-random manner from among a set of L steering matrices, where L&#x3e;1) for each subblock. Each data symbol subblock is spatially processed with the steering matrix selected for that subblock to obtain transmit symbols, which are further processed and transmitted via Ntransmit antennas in one transmission span. The Ndata symbol blocks are thus spatially processed with Nsteering matrices and observe an ensemble of channels.

Rolling paint caddy

A multiple-access MIMO WLAN system that employs MIMO, OFDM, and TDD. The system (1) uses a channel structure with a number of configurable transport channels, (2) supports multiple rates and transmission modes, which are configurable based on channel conditions and user terminal capabilities, (3) employs a pilot structure with several types of pilot (e.g., beacon, MIMO, steered reference, and carrier pilots) for different functions, (4) implements rate, timing, and power control loops for proper system operation, and (5) employs random access for system access by the user terminals, fast acknowledgment, and quick resource assignments. Calibration may be performed to account for differences in the frequency responses of transmit/receive chains at the access point and user terminals. The spatial processing may then be simplified by taking advantage of the reciprocal nature of the downlink and uplink and the calibration.

MIMO WLAN system

Techniques to use OFDM symbols of different sizes to achieve greater efficiency for OFDM systems. The system traffic may be arranged into different categories (e.g., control data, user data, and pilot data). For each category, one or more OFDM symbols of the proper sizes may be selected for use based on the expected payload size for the traffic in that category. For example, control data may be transmitted using OFDM symbols of a first size, user data may be transmitted using OFDM symbols of the first size and a second size, and pilot data may be transmitted using OFDM symbols of a third size or the first size. In one exemplary design, a small OFDM symbol is utilized for pilot and for transport channels used to send control data, and a large OFDM symbol and the small OFDM symbol are utilized for transport channels used to send user data.

OFDM communication system with multiple OFDM symbol sizes

A MIMO system supports multiple spatial multiplexing modes for improved performance and greater flexibility. These modes may include (1) a single-user steered mode that transmits multiple data streams on orthogonal spatial channels to a single receiver, (2) a single-user non-steered mode that transmits multiple data streams from multiple antennas to a single receiver without spatial processing at a transmitter, (3) a multi-user steered mode that transmits multiple data streams simultaneously to multiple receivers with spatial processing at a transmitter, and (4) a multi-user non-steered mode that transmits multiple data streams from multiple antennas (co-located or non co-located) without spatial processing at the transmitter(s) to receiver(s) having multiple antennas. For each set of user terminal(s) selected for data transmission on the downlink and/or uplink, a spatial multiplexing mode is selected for the user terminal set from among the multiple spatial multiplexing modes supported by the system.

MIMO system with multiple spatial multiplexing modes

A method for estimating a feedback channel for a wireless repeater using frequency domain channel estimation estimates an error correction term using a most recent channel estimate and cancels the error correction term from a current block of the receive signal. Then, the feedback channel is estimated using frequency domain channel estimation and using a current block of the pilot signal and the corrected block of the receive signal. A channel estimate error term may also be estimated and subtracted directly from the channel estimate.

Removal of ICI/ISI errors in frequency domain channel estimation for wireless repeaters

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Ashland, MA, United States of America

Steven J Howard