2952 results about "MIMO" patented technology

Various embodiments of multi input multi output (MIMO) communication systems include a transmit Tomlinson-Harashima Precoding (THP) technique and a single carrier frequency domain equalization (SC-FDE) technique. Parallel THP-FDE and successive THP-FDE are proposed based on the minimum mean square error (MMSE) criterion. For the successive THP-FDE technique, where all transmit streams are subsequently precoded, both suboptimal and optimal MMSE ordering algorithm are set forth. Since the feedback processing is performed at the transmitter, no error propagation problem exists in the THP-FDE MIMO techniques, yielding significant performance improvements over conventional FDE MIMO techniques. Applying channel prediction and THP compensation techniques can also further enhance performance.

In a wireless network comprising a plurality of subscriber stations and a base station capable of providing service to the subscriber stations, a subscriber station is provided that includes a rank selector and a scheduling data reporter. The rank selector is operable to select a rank for the subscriber station. The rank is operable to identify a number of antennas for transmitting data streams from the base station to the subscriber station. The scheduling data reporter is operable to report scheduling data, including the rank, to the base station.

An adaptive transmission scheme provides multiple levels of adaptation. At a first level, a selection is made between a limited feedback or open loop scheme and a rich feedback or closed loop scheme. At a second level of adaptation, a diversity mode is selected. Additional levels of adaptation could be employed.

A radio-over-fiber (RoF) wireless picocellular system adapted to form an array of substantially non-overlapping individual picocells by operating adjacent picocells at different frequencies is operated to form one or more combined picocells. The combined picocells are formed from two or more neighboring picocells by the central head-end station operating neighboring picocells at a common frequency. Communication between the central head-end station and a client device residing within a combined picocell is enhanced by the availability of two or more transponder antenna systems. Thus, enhanced communication techniques such as antenna diversity, phased-array antenna networks and multiple-input/multiple-output (MIMO) methods can be implemented to provide the system with enhanced performance capability. These techniques are preferably implemented at the central head-end station to avoid having to make substantial changes to the wireless picocellular system infrastructure.

Disclosed is a method for transmitting a signal in a mobile communications system using a plurality of transmit/receive antennas. A method for transmitting a signal in accordance with an embodiment of the present invention comprises the steps of: a receiving end's calculating a signal to interference noise ratio (SINR) with respect to every antenna pairs configuring STTD pairs to be transmittable from a transmitting end; feedbacking information indicating an antenna pair having the greatest SINR to the transmitting end; and the transmitting end's performing a D-STTD transmission through the antenna pair determined by the feedbacked information. A method for transmitting a signal in accordance with another embodiment of the present invention comprises the steps of: a receiving end's feedbacking information of an antenna pair and/or an eigenvector (weight vector) of a channel matrix with respect to transmit antennas included in the space-time multiplexing (STTD) pair to a transmitting end; and the transmitting end's forming beam by multiplying a symbol with respect to each STTD pair by the eigenvector, and thereafter transmitting the beam through each transmit antenna (in case of using two antennas) or a transmit antenna pair (in case of using more than four antennas) determined by the information of the antenna pair.

A node in a first network requests a communication channel from a second network. Upon receiving a channel assignment, nodes in the first network employ the assigned channel for communicating in a manner that is transparent to the second network. A transmitting node selects a decoy data signal as a carrier signal, synthesizes data-bearing channel distortions; and distorts the carrier signal with the channel distortions prior to transmission. An undistorted version of the decoy data may be transmitted to an intended receiver. The receiver distinguishes between the synthesized data-bearing channel distortions and natural channel distortions to decrypt the data. In a MIMO system, the transmitter generates a MIMO precoding matrix from a message to be sent to the receiver and multiplies the decoy data signal vector with the MIMO precoding matrix.

The present invention relates to a method for generating an uplink reference signal in a system supporting plural uplink-access transmission modes. The method comprises: a step for transmitting the reference signal configuration information about the configuration of a reference signal from a base station to a user device through an uplink grant PDCCH (Physical Downlink Control Channel), and a step for receiving from the user device a sub-frame including the reference signal that is generated based on the reference signal configuration information. The reference signal configuration information is prepared for plural uplink access transmission modes and includes a cyclic shift value for the sequence of the reference signal. The reference signal is supposed to be transmitted to an uplink, and the user device is set up to be operated in the uplink-access transmission mode that corresponding to the reference signal configuration information.

A modular test chassis for use in testing wireless devices includes a backplane and a channel emulation module coupled to the backplane. The channel emulation module comprises circuitry for emulating the effects of a dynamic physical environment (including air, interfering signals, interfering structures, movement, etc.) on signals in the transmission channel shared by the first and second device. Different channel emulation modules may be included in the test system depending upon the protocol, network topology or capability under test. A test module may be provided to generate traffic at multiple interfaces of SISO or MIMO DUTs to enable thorough testing of device and system behavior in the presence of emulated network traffic and fault conditions. A latency measurement system and method applies timestamps frames as they are transmit and received at the test module for improved latency measurement accuracy.

The present invention provides for a communication system and method that overlays signals which are simultaneously mutually orthogonal in both the time and frequency domains, thereby enhancing spectral efficiency. Whereas commonly used sinusoids provide only two mutually orthogonal functions (sine and cosine), certain polynomials provide multiple orthogonal functions, which are also finite in both time and frequency. Using multiple orders of the orthogonal functions allows overlaying signals within a symbol to generate a modulated signal carrying more information than with traditional QAM. Correlating a received signal with locally generated replicas of the orthogonal functions allows demodulation of the signal. This modulation is applicable to twisted pair, cable, fiber, satellite, broadcast and all types of wireless access. The method and system are compatible with many current and future multiple access systems, including EV-DO, UMB, WiMax, WCDMA (with or without MBMS/MIMO), HSPA Evolution, and LTE.

An apparatus and method for supporting a plurality of MIMO modes in a wireless communication system are provided, in which a receiver selects one of the plurality of MIMO modes according to at least one of a received signal strength, a speed of the receiver, a correlation between a transmitter and the receiver, a presence or absence of channel quality information, a precoding index, and an antenna information, a rank, and a number of users, generates feedback information in a transmission format corresponding to the selected MIMO mode, and transmits the feedback information to the transmitter using a feedback resources allocated according to the selected MIMO mode.

A receiver includes a receiver circuit that decodes multiple signals of interest contained in a composite receive signal. The receiver comprises at least one Generalized RAKE combining circuit and a joint demodulation circuit and generates a detected signal at an output. The joint demodulation circuit contains a reduced search soft value generator circuit and generates soft bit values that represent coded bits received from the transmitter.

The wireless communication devices A and B determine the optimal diversity combining weight information that optimizes a diversity reception state at each antenna group A₁, A₂, . . . , A_P through two-way training signal transfer between the wireless communication devices A and B. This optimal diversity combining weight information is set to each antenna of each antenna group A₁, A₂, . . . , A_P. Wireless communication units A′, B′ perform spacial mapping of signals from antenna group A₁, A₂, . . . , A_P using MIMO technology. Communication area can be enlarged by hierarchization MIMO using the optimal diversity combining weight information.

The invention discloses an MIMO system and an application method thereof for adaptive antenna selection. The MIMO system comprises a transmitter, a receiver and a wireless channel; the process of the antenna selection which is realized in the MIMO system adopts an iterative feedback structure; a subset is selected quickly from a large amount of antenna sets by using the characteristic of 60 GHz channel without accurate channel estimation, so that a subchannel corresponding to an antenna subarray is optimal in the sense of a defined target function; and high speed data transmission is performed by using the selected optimal antenna subarray. The invention provides the rapid and efficient application method for the MIMO system along with low cost, and solves the technical problems of high complexity and low efficiency of the traditional antenna selection method in the large-scale the MIMO system. An experiment proves that: the adopted method can obtain good performance only through several iterations and low computational complexity; and the system can better support the application of the large-scale the antenna array.

A system for doing BLAST with fewer receive antennas or even only one receiving antenna is provided. A system implementation architecture is provided together with a detailed analysis on its principle and theory behind this engineering solution to reduce the MIMO technology cost by using fewer antennas whilst achieving high spectrum efficiency. Examples are provided on how to implement this idea in a CDMA platform and in a OFDM platform. For the CDMA system, the code space is automatically doubled or tripled and therefore a significant system capacity increase is realized. For OFDM systems, the throughput is doubled similar as 2×2 blasting. The system complexity is minimum and full standards backward compatibility can be achieved.

A broadcast signal transmitter according to one embodiment of the present invention comprises: an input signal generating unit which generates a first input signal and a second input signal; a MIMO encoder which performs MIMO processing of the first input signal and the second input signal to output a first transmission signal and a second transmission signal; and a first OFDM generator and a second OFDM generator which performs OFDM modulation of the first transmission signal and OFDM modulation of the second transmission signal. The MIMO processing applies a MIMO matrix to the first input signal and the second input signal. The MIMO matrix changes phases using a phase rotation matrix, and adjusts power of the first input signal and second input signal using parameter a, wherein the parameter is set to different values in accordance with the modulation types of the first input signal and second input signal.

A master application device comprises a plurality of distributed transceivers, a central baseband processor, and a network management engine that manages operation of the master application device and end-user application devices. The master application device communicates data streams to the end-user devices utilizing one or more distributed transceivers selected from the plurality of distributed transceivers. The selected distributed transceivers are dynamically configured to switch between spatial diversity mode, frequency diversity mode, multiplexing mode and MIMO mode based on corresponding link quality and propagation environment. Digital signal processing needed for the selected distributed transceivers is performed by the central baseband processor. The network management engine continuously monitors communication environment information to configure beamforming settings and/or antenna arrangement for the selected distributed transceivers. Connection types, communication protocols, and/or transceiver operation modes are determined for the selected distributed transceivers. Resources are allocated to the selected distributed transceivers to continue subsequent data communication.

A mobile broadband wireless system including at least two pairs of nodes arranged in a cluster, each pair coupled to form a link for wireless communication; each node including: an RF transceiver with associated modem; an antenna array arrangement, each antenna having a beam pattern selected to improve quality of transmission, coupled to the modem and arranged for multiple concurrent transmissions; a controller for controlling the transceiver, modem and antenna array arrangement for providing point to point communication; the controller including means for allocating MIMO streams and modulation to different antennas in the antenna array arrangement; and at least one interference mitigation mechanism implemented by the controller to minimize interference within the cluster during multiple concurrent transmissions, and a method of wireless communication.

A communication system based upon frequency-domain MIMO processing is disclosed. A transmitting device of the communication system transforms time-domain signals into frequency-domain signals, and weights each frequency-domain signal to form weighted frequency-domain signals with each weighted frequency-domain signal being a function of each frequency-domain signal. The transmitting device transmits weighted time-domain waveforms as a function of the weighted frequency-domain signals. In response thereto, a receiving device of the communication system provides frequency-domain samples that are a function of the one or more weighted time-domain waveforms and weights each frequency-domain sample to form one or more weighted frequency-domain samples with each weighted frequency-domain sample being a function of each frequency-domain sample. The receiving device decodes the weighted frequency-domain sample to obtain the information represented by the time-domain signals.

Disclosed is a beam identification method in a MIMO beam forming communications system. The method comprises: a base station sending multiple beam training signals to a terminal, each beam training signal corresponding to one beam, and each beam covering a different direction; the terminal detecting the beam training signals, determining a selected beam according to a result of the detection, and feeding back information indicating the selected beam to the base station; the base station determining, according to the information indicating the selected beam fed back by the terminal, a beam used for sending data information. Also disclosed are a related beam identification device and system in a MIMO beam shaping communications system.

A beamforming method in a communication system having a transmitter for transmitting signals to users on a plurality of transmit antennas, and spatially identifying the users and a plurality of receivers for receiving the signals discriminately. A beamforming weight is determined based on channel information received from each of the receivers, based on whether the each receiver uses a single antenna or a plurality of antennas. A transmission signal is multiplied by the beamforming weight and transmitted.

The scheduler in a base station needs CQI information from a terminal for all re-use sets every 5 ms. to decide on which re-use set to schedule a given terminal. For MIMO users, the problem is that the CQI cannot be reconstructed for all re-use sets, using the current design. Solution: (1) For Multiple Code Word MIMO users, a MIMO VCQI connection layer message enables the base station to reconstruct the MIMO-CQI for all reuse sets on a packet-by-packet basis. This will enable dynamic scheduling (RESTRICTIVE REUSE) gains. (2) For Single Code Word users, dynamic RESTRICTIVE REUSE can be obtained by changing the CQI reporting format, and also sending a MIMO-VCQI connection layer message. (3) For Single Code Word design, quasi-static scheduling gains can be obtained by sending a MIMO-VCQI connection layer message.

A communication system performs adaptive scheduling by considering present and past reported CQI values and other indications of channel conditions in scheduling a Modulation and Coding Scheme (MCS) and then executing a ‘dithering’ function in order to effectuate an MCS that is intermediate between adjacent discrete MCSs. In one embodiment, the communication system determines a first MCS based on a channel quality metric received from a mobile station (MS) and then transmits data utilizing the first MCS. The communication system assigns weights to each of the first MCS and a second MCS based on whether the transmitted data is acknowledged and, based on the assigned weights, selects one of the first and second MCSs for a subsequent transmission of data to the MS. The communication system also may assign weights to each of a first and second MCS based on a transition between a MIMO-A and a MIMO-B transmission scheme.