83 results about "Space time transmit diversity" patented technology

Aspects of the present invention provide MAC enhancements to support the PHY features of a MIMO-OFDMA framework. The MAC enhancements involve DL burst assignment to support adaptive MIMO transmission, UL burst assignment to support adaptive MIMO transmission, fast feedback channel operation to support wireless terminal dynamic feedback of MIMO mode selection, for example space time transmit diversity (STTD) or spatial multiplexing (SM), and / or permutation mode selection, for example diversity or adjacent subcarrier mode, dynamic CQICH allocation and de-allocation and the use of CQICH_ID for DL burst allocation. One or more of these enhancements is included in a given implementation. Methods are also provided for implementing the MAC enhancements.

The present invention selects a space-time encoding mode to use when transmitting with spatial diversity based on the receive diversity associated with a receiver device and the quality of the transmission channels based on information fed back from the receiver device. The selectable space-time encoding modes are preferably space-time transmit diversity encoding and a version of BLAST-type encoding. Further, modulation modes, error encoding rates, or a combination thereof, may also be based on the quality of the transmission channels and the available diversity of the receiver device.

A method of supporting a hybrid automatic retransmission request (HARQ) in an orthogonal frequency division multiplexing access (OFDMA) radio access system is disclosed. Preferably, the method comprises receiving a downlink data frame comprising a data map information element and a data burst comprising a plurality of layers, wherein each layer is encoded with a corresponding channel encoder, and wherein the data map information element is configured to support multiple antennas to achieve space time transmit diversity by providing control information associated with each one of the plurality of layers, wherein the control information comprises allocation of acknowledgement status channels corresponding to the plurality of layers, and transmitting in an uplink data frame a plurality of acknowledgement status, each acknowledgement status being associated with whether a corresponding layer of the plurality of layers is properly decoded.

A linear transformation of parallel space-time transmit diversity encoded streams; also, asymmetrical symbol mapping of parallel streams. Separately or together, these improve error rate performance as well as system throughput. Preferred embodiments include CDMA wireless systems with multiple antennas.

A circuit is designed with a measurement circuit (432). The measurement circuit is coupled to receive a first input signal (903) from a first antenna (128) of a transmitter and coupled to receive a second input signal (913) from a second antenna (130) of the transmitter. Each of the first and second signals is transmitted at a first time. The measurement circuit produces an output signal corresponding to a magnitude of the first and second signals. A control circuit (430) is coupled to receive the output signal and a reference signal. The control circuit is arranged to produce a control signal at a second time in response to a comparison of the output signal and the reference signal.

Space-time transmit diversity spread spectrum receiver architectures and methods are described for reducing interference, particularly the interference observed at a user-end terminal in a W-CDMA 3G mobile communications system. Interpath interference which arises due to non-zero cross and auto correlation of more than one spreading code is suppressed by estimating a transmitted signal stream, or a plurality of such signal streams in the case of a plurality of multipath components, respreading this estimated signal and subtracting non-orthogonal interference contributions from a received signal. The techniques provide an improved bit error rate or equivalently, enhanced capacity for a digital mobile communications network.

A method of retransmitting packet data in a wireless communication system comprises receiving a link map information element from a transmitting station having three antennas to achieve space time transmit diversity, wherein first, second and third packet data are transmitted from first, second and third antenna of the transmitting station, respectively. The method also comprises transmitting a non-acknowledgement signal to the transmitting station if at least one packet data from the transmitting station is not properly decoded. The method also comprises receiving the packet data from the transmitting station, wherein at least two of retransmitted packet data are transmitted from different antennas of the transmitting station, and one of retransmitted packet data is transmitted from the same antenna of the transmitting station. The retransmitted packet data are received with an information element comprising a retransmission count associated with a number of retransmission made by the transmitting station.

Aspects of the present invention provide MAC enhancements to support the PHY features of a MIMO-OFDMA framework. The MAC enhancements involve DL burst assignment to support adaptive MIMO transmission, UL burst assignment to support adaptive MIMO transmission, fast feedback channel operation to support wireless terminal dynamic feedback of MIMO mode selection, for example space time transmit diversity (STTD) or spatial multiplexing (SM), and / or permutation mode selection, for example diversity or adjacent subcarrier mode, dynamic CQICH allocation and de-allocation and the use of CQICH_ID for DL burst allocation. One or more of these enhancements is included in a given implementation. Methods are also provided for implementing the MAC enhancements.

Embodiments of the invention provide orthogonal Frequency Division Multiplexing-Space-time Block Codes (OFDMSTBC) mappings for code rate 1, 2 and 4 codes for 4 Transmit Antennas. To overcome the innate weakness of known codes, a new class of STBC codes is provided which is particularly suited for OFDM applications, although other applications are also contemplated. Codes for STBC mappings in the time direction, the frequency direction and a combined time frequency mapping for multiple antennas are provided. In OFDM applications, these codes exploit the properties of OFDM and FEC codes to substantially maintain the advantages of Alamouti codes. Furthermore, while the detailed examples given herein focus on four antenna applications, they can be easily extended to systems with more than four antennas.

A closed-loop STTD system extended from an open-loop STTD system adopting four antennas transmission diversity technique and its signal transmitting method are disclosed. The signal transmitting method in a closed-loop space-time transmit diversity (STTD) system having a plurality of transmission antennas, includes: space-time coding symbols to be transmitted; classifying the coded symbols to certain groups; and multiplying different weight values to each transmission symbol group and transmitting them.

The present invention discloses a method of adaptive weighting space-time transmit diversity, comprising: symbols to be transmitted at a transmitting end being output after being space-time encoded according to certain regulation, and the current transmission powers of the two antennae being real-timely adjusted according to the given transmission power weight values; after the transmission powers are determined, the space-time encoded output signals being sent out at two independent antennas by transmitting antenna array in terms of the current transmission power; the fading characters of two wireless channels being estimated by the receiver at a receiving end according to the present received signals and then fed back to the transmitting end; the transmitting end receiving and obtaining the fading amplitude characters of two wireless channels through feedback channel, calculating new adaptive weight values of transmission powers, and adjusting transmission powers according to these weight values. The present invention also discloses a system for implementing the above method of adaptive weighting Space-time Transmit Diversity. In term of the method and structure, the transmission powers can be dynamically adjusted in adaptive weighting manner, in order to boost system performance gain.

This invention extends Alamouti's scheme for wideband TDMA systems; it then works in conjunction with time-domain equalization. In fact, the present invention envisages time-domain DFE or MLSE equalization (which is more robust than linear frequency-domain equalization) via the use of a training mid-amble to separate adjacent sub-blocks; this mid-amble is used in equalizer training and its direct and inter-symbol interference contributions to the received signal, are subtractively eliminated to facilitate the detection process itself. This approach may be applied to all systems in time-dispersive propagation media, where the burst or slot length is short enough that the fading can be considered time-invariant over its duration.

A method and apparatus for determining a shuffling pattern in a DSTTD. In the apparatus, a channel estimator estimates channel characteristics from a plurality of transmit antennas to a plurality of receive antennas. A shuffling pattern selector calculates a minimum receive SNR for each of all available shuffling patterns, and selects a shuffling pattern having the largest minimum receive SNR as the optimum shuffling pattern. This efficient shuffling pattern selection directly improves BER performance at a receiver.

Techniques for transmitting data using a combination of transmit diversity schemes are described. These transmit diversity schemes include spatial spreading, continuous beamforming, cyclic delay diversity, space-time transmit diversity (STTD), space-frequency transmit diversity (SFTD), and orthogonal transmit diversity (OTD). A transmitting entity processes one or more (ND) data symbol streams based on a transmit diversity scheme (e.g., STTD, SFTD, or OTD) to generate multiple (NC) coded symbol streams. Each data symbol stream may be sent as a single coded symbol stream or as multiple (e.g., two) coded symbol streams using STTD, SFTD, or OTD. The transmitting entity may perform spatial spreading on the NC coded symbol streams with different matrices to generate multiple (NT) transmit symbol streams for transmission from NT antennas. Additionally or alternatively, the transmitting entity may perform continuous beamforming on the NT transmit symbol streams in either the time domain or the frequency domain.

Aspects of the present invention provide MAC enhancements to support the PHY features of a MIMO-OFDMA framework. The MAC enhancements involve DL burst assignment to support adaptive MIMO transmission, UL burst assignment to support adaptive MIMO transmission, fast feedback channel operation to support wireless terminal dynamic feedback of MIMO mode selection, for example space time transmit diversity (STTD) or spatial multiplexing (SM), and / or permutation mode selection, for example diversity or adjacent subcarrier mode, dynamic CQICH allocation and de-allocation and the use of CQICH_ID for DL burst allocation. One or more of these enhancements is included in a given implementation. Methods are also provided for implementing the MAC enhancements.

To provide transmission and reception diversity schemes for a powerful, flexible and less complex bandwidth-efficient space-time modulation scheme there is proposed a method of and apparatus for differential multiple-norm space-time transmit diversity from a unitary space-time modulation scheme using at least two transmit antennas. In a first step a group of transmission bits is divided into a first sub-group of transmission bits and a second sub-group of transmission bits. In a second step the first sub-group of transmission bits is mapped onto a constellation matrix of a differential unitary space-time modulation scheme. In a third step a scaling factor is determined from the second sub-group of transmission bits. In a fourth step a transmission matrix is sep up through differential encoding of the constellation matrix and a previously determined transmission matrix in combination with scaling by the scaling factor. The differential multiple-norm transmit diversity according to the present invention improves distance properties of the modulation scheme which are relevant for achievable error rates and extends higher order modulation also to the area of differential transmit diversity schemes from unitary designs.

A method and system that increases transmit diversity gain in a wireless communication system. The system includes a transmitter with 2N transmit 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−1 stages is a block level space-time transmit diversity encoder, for a total of N stages. The last stage is connected to the 2N antennas. The transmitter generates pairs of symbols in a form X1 and X2, The pairs of symbols are encoded by the first stage to produce a 21×21 output matrix C. Then, in each next block level stage n, the 2n−1×2n−1 output matrix of a previous stage is encoded to a 2n×2n output matrix, until a final output matrix has 2N rows 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 2N transmit antennas. A transmit weight is applied to each transmit symbol before transmitting the transmit symbol.

A method of supporting a hybrid automatic retransmission request (HARQ) in an orthogonal frequency division multiplexing access (OFDMA) radio access system is disclosed. Preferably, the method comprises receiving a downlink data frame comprising a data map information element and a data burst comprising a plurality of layers, wherein each layer is encoded with a corresponding channel encoder, and wherein the data map information element is configured to support multiple antennas to achieve space time transmit diversity by providing control information associated with each one of the plurality of layers, wherein the control information comprises allocation of acknowledgement status channels corresponding to the plurality of layers, and transmitting in an uplink data frame a plurality of acknowledgement status, each acknowledgement status being associated with whether a corresponding layer of the plurality of layers is properly decoded.

The present invention provides an apparatus, system and method for removal of interference due to multi-path for multiple transmit antennas (hereinafter referred to as MTA-MPIC) for High Speed Downlink Packet Access (HSDPA) encoded for transmit diversity, such as Space-Time Transmit Diversity (STTD). For a single receive antenna, the signal is received (25) and each multi-path delayed signal is demodulated (21). The demodulation can include long code removal and despreading. Subsequently, each demodulated signal is received by the RAKE receiver (22) for determining the channel estimate and channel normalization for the total HSDPA signal, and for computing space-time decoding for the HSDPA signal. Following the space-time decoding, a data decision is made (23). Next, reconstructed interference signals are generated (24) and combined with the received signal (25). For other user signals, an interference estimate is made from the despreader (322) outputs without applying the RAKE / space-time coding operations.

Space time transmit diversity (9, 14, 17, 19) is applied at the block level to an original block of bits (12) in order to reduce the effects of fading in wireless communication systems that use nonlinear modulation schemes (13, 33). At the receiving end, fading parameters (α1, α2) are estimated (αE1, αE2) and the properties of complex conjugates are utilized (28, 29, 201, 202) to produce a result (r1, r2) that is representative of the original block of bits.

A circuit is designed with a matched filter circuit including a plurality of fingers (700, 702, 704) coupled to receive a data symbol. Each finger corresponds to a respective path of the data symbol. Each finger produces a respective output signal. A plurality of decoder circuits (706, 708, 710) receives the respective output signal from a respective finger of the plurality of fingers. Each decoder circuit produces a respective output signal. A joint detector circuit (1310) is coupled to receive each respective output signal from the plurality of decoder circuits. The joint detector circuit produces an output signal corresponding to a predetermined code.

The present invention relates to a transmitting device and a receiving device in a wireless orthogonal frequency division multiplex (OFDM) communication system with space time transmit diversity (STTD). Further, the present invention relates to a channel estimation method for performing a channel estimation in such a wireless communication system, in which the transmitting device comprises a first and a second antenna for transmitting signals with space time transmit diversity. The first and the second antenna means are arranged spaced apart from each other in a space diversity arrangement, whereby first and second pilot symbols are transmitted via said first and said second antenna means, respectively. Some of the second pilot symbols are orthogonal to corresponding ones of the first pilot symbols, so that a channel estimation to separately determine the transmission quality of signals transmitted from the first and the second antenna means, respectively, can be performed in a receiving device which receives the signals with only one single antenna.

A method for transmitting feedback information in a mobile communication system using Multiple Input Multiple Output (MIMO) is provided. The method includes, when knockdown precoding is used and Antenna Selection precoding is used, setting an index field for indicating a universal matrix of a precoding matrix of a first reverse feedback channel to a value indicating whether Antenna Selection Space Time Transmit Diversity (STTD) is present; when the knockdown precoding is used and the Antenna Selection precoding is used, writing antenna selection information in a vector bitmap field of the first reverse feedback channel; and when the knockdown precoding is used and the Antenna Selection precoding is used, estimating Channel Quality Information (CQI) according to the antenna selection information and writing the estimated CQI in a CQI field of a second reverse feedback channel.

Techniques for transmitting data using a number of diversity transmission modes to improve reliability. At a transmitter, for each of one or more data streams, a particular diversity transmission mode is selected for use from among a number of possible transmission modes. These transmission modes may include a frequency diversity transmission mode, a Walsh diversity transmission mode, a space time transmit diversity (STTD) transmission mode, and a Walsh-STTD transmission mode. Each diversity transmission mode redundantly transmits data over time, frequency, space, or a combination thereof. Each data stream is coded and modulated to provide modulation symbols, which are further processed based on the selected diversity transmission mode to provide transmit symbols. For OFDM, the transmit symbols for all data streams are further OFDM modulated to provide a stream of transmission symbols for each transmit antenna used for data transmission.

A method transmits an input stream of data symbols in a multiple-input, multiple-output wireless communications system. The input stream is demultiplexed into M substreams. Each of the M substreams is adaptively modulated and coded to a coded substream according to channel conditions. A first of the M coded substreams is space-time transmit diversity encoding into two space-time transmit diversity encoded substreams. There is one space-time transmit diversity encoded substream for each one of two transmit antennas. Each other coded substream is transmitted directly by a corresponding one of remaining M−1 transmit antenna.

The invention relates to a method for using antenna to selectively operate the self-adaptive STTD. The receiving terminal comprises following steps: according to the estimation of channel, calculating the SINR of coded STTD in different combination of different emission antennas of each sub-flow; according to the SINR, calculating the total transmission property parameter in said combination; selecting the antenna combination with best total transmission property as present selected combination to attain the selective parameter; according to the SINR, selecting AMC parameters for each emission sub-flow; returning the antenna selective parameter and the AMC parameter via the feedback channel to the sending terminal. And the sending terminal comprises: according to the returned AMC parameter, processing the AMC on the data; processing STTO coding; and according to the returned antenna selective parameter, selecting the antenna combination via which to send the data.

A power control system and method for communication system using space-time transmit diversity scheme. In the power control method, transmission power information of a plurality of antennas or a plurality of subcarriers is monitored. A new space-time code is generated by concatenating the monitored transmission power information and symbols to be transmitted. Symbols encoded using the generated space-time code are generated and the encoded symbols are transmitted. Accordingly, after determining the transmission power of each antenna, the transmission power information is monitored so that the transmission power information that does not experience the channel gain can be used at a next slot. Therefore, the performance degradation due to the round trip time can be reduced, thereby improving the system capacity and performance.

The present invention relates to a transmitting device and a receiving device in a wireless orthogonal frequency division multiplex (OFDM) communication system with space time transmit diversity (STTD). Further, the present invention relates to a channel estimation method for performing a channel estimation in such a wireless communication system, in which the transmitting device comprises a first and a second antenna for transmitting signals with space time transmit diversity. The first and the second antenna means are arranged spaced apart from each other in a space diversity arrangement, whereby first and second pilot symbols are transmitted via said first and said second antenna mean, respectively. Some of the second pilot symbols are orthogonal to corresponding ones of the first pilot symbols, so that a channel estimation to separately determine the transmission quality of signals transmitted from the first and the second antenna means, respectively, can be performed in a receiving device which receives the signals with only one single antenna.