Mitsubishi Electric Research Laboratories, Inc.

Mitsubishi Electric Research Labs.

Jyhchau Horng

Jinyun Zhang

Jay Bao

Philip Orlik

Xiaoyang Lee

Phillip Orlik

Ling Li

A method for transmitting a stream of data symbols in a multiple-input/multiple-output (MIMO) wireless communications system including Ntransmitting antennas. The stream of data symbols is first demultiplexed into M sub-streams, where M=N/2. Then, space-time transmit diversity encoding is applied to each sub-stream to generate a pair of transmit signals. Power is allocated dynamically to each transmit signal of each pair of transmit signals according to a corresponding feedback signal received from a receiver of the transmit signal. The feedback signal including a ratio of magnitude sums of channel coefficients for channels used for the transmit signals.

Adaptive space-time transmit diversity coding for MIMO systems

A method and system transmits a stream of data symbols in a multiple-input/multiple-output wireless communications system that includes M pairs of transmitting antennas. The stream of data symbols are demultiplexed into M sub-streams and adaptively modulated and coded to a maximum data rate while achieving a predetermine performance on an associated channel used to transmit the sub-stream. Space-time transmit diversity encoding is applied to each coded sub-stream to generate two output streams, one output stream for each antenna.

MIMO systems with rate feedback and space time transmit diversity

A multi-path interference canceller cancels interference in a signal received by a receiver in a wideband CDMA communications system. A first stage of the canceller has as input the received signal. Each next stage has as input a delayed version of the input of the previous stage. Each stage includes a first channel estimation and interference generation unit for estimating interference in high-speed signal components of the input signal, and a second channel estimation and interference generation unit for estimating interference in low-speed signal components of the input signal. The interference estimated in the previous stage by the first and second channel estimation and interference generation units is then removed from the input signal of the next stage.

Intra-cell interference cancellation in a W-CDMA communications network

A method and system that increases transmit diversity gain in a wireless communication system. The system includes a transmitter with 2transmit antennas, where N is greater than one, and a receiver with one or more receive antenna. The transmitter includes N stages connected serially to each other. The first stage is a symbol level space-time transmit diversity encoder. Each of the next N&#x2212;1 stages is a block level space-time transmit diversity encoder, for a total of N stages. The last stage is connected to the 2antennas. The transmitter generates pairs of symbols in a form Xand X, The pairs of symbols are encoded by the first stage to produce a 2&#xd7;2output matrix C. Then, in each next block level stage n, the 2&#xd7;2output matrix of a previous stage is encoded to a 2&#xd7;2output matrix, until a final output matrix has 2rows of transmit symbols. The transmit symbols of the final output matrix are fed, in a left-to-right order, for each row, in a top-to-bottom order, to a corresponding different one of the 2transmit antennas. A transmit weight is applied to each transmit symbol before transmitting the transmit symbol.

Transmit diversity gain for wireless communications networks

A method and system for equalizing a signal transmitted via a channel of a communications system stores an input signal received via the channel in a main buffer. A training signal portion of the received input signal is stored in a circular buffer as a circulating training signal. A mean square error of the training signal is minimized while estimating the transmitted signal, until the mean square error is less than a predetermine threshold. In this case, the input signal received via the channel is equalized directly to make decisions on symbols of the signal transmitted via the channel. During an initial stage of training, the mean square error is determined directly from the training signal, during subsequent stages of training the circulating training signal is used.

Signal circulation for adaptive signal equalization in digital communication systems

A method for communicating a bit stream using turbo coding encodes each input bit in the bitstream using a single 1/3 rate turbo encoder to produce a set of three bits. One of the three bits in each set is repeated to produce a set of four bits for each input bit. A time interval between the four bits is increased before transmitting the set of four bits on a communications channel. In a receiver, the time interval between the set of four bits received via the communications channel is decreased using a de-interleaver. The received set of four bits are diversity combine into a received set of three bits, and then a single 1/3 rate turbo decoder is used to recover an output bit for each input bit.

Turbo coding for fast fading channels

A digital receiver detects symbols in a baseband signal in a DS-CDMA network. The receiver includes multiple spaced apart antennas. A time-frequency rake receiver is connected to each of the antennas. An interference canceller is connected to each output of each of the rake receiver. Each interference canceller produces a contributing symbol in parallel. A diversity combiner determines a decision symbol corresponding to the baseband signal from the contributing symbols.

Adaptive DS-CDMA multi-user receiver with diversity combining for interference cancellation

A method reduces interference adaptively in a CDMA receiver. A baseband signal is demodulated to determine target symbols. The baseband signal is also demodulated to estimate interfering symbols. The interfering symbols are modulated to generate a cancellation signal, and the cancellation signal is subtracted from the base band signal to reduce interference in the target symbols.

Adaptive multi-users interference reduction and cancellation in a CDMA network

In a digital radio receiver, transmitted symbols are recovered from a received signal that includes tim-shifted and frequency-shifted copies of a transmitted signal. A channel estimator extracts channel characteristics from a training signal. Receiver data and software for executing in a processor are stored in a memory connected to the processor. A parameter controller generates receiver configuration parameters from the channel characteristics and the receiver data. The received signal is decomposed into a matrix of samples according to the receiver configuration parameters to adapt the receiver to a multiple multiplexing schemes. An inner product is formed of the samples and channel characteristics, and the transmitted symbols are recovered from the inner product.

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Warren, NJ, United States of America

Jyhchau Horng