Abstract: This invention presents methods and systems for RF path and antenna connection and switch in wireless communication comprising an electromagnetic lens and M antennas; N (N<=M) radio frequency (RF) transmitting and receiving chains/paths that contain Low Noise Amplifiers (LNAs), RF filters, mixers, amplifiers; a plural of digital to analog converters (DACs) and analog to digital converters (ADCs); a connection and switch network that maps the signals from M antennas to N RF paths in the UL or mapping the signals from N RF path to M antennas in the DL, and a processor unit that measures and estimates the receiving signal strength (RSS) or the equivalent metrics on each antenna for each user equipment (UE) based on the received UL reference signals, and drives signals to control the connection and switch network to connect RF paths and antennas for data transmission.

Abstract: A wireless apparatus multiplies, by a first weight corresponding to each of a plurality of beams, a received signal corresponding to a reference signal transmitted from each of wireless terminals, estimates a channel response associated with each of the beams, computes a predetermined metric for each combination of beams to be used, selects the beams to be used when performing signal detection with respect to a received signal into which radio signals transmitted from the wireless terminals are spatially multiplexed based on the predetermined metric, determines a second weight to be used for the signal detection and multiplies, by the second weight, the received signal into which radio signals transmitted from the wireless terminals are spatially multiplexed to perform the signal detection.

Abstract: There is provided mechanisms for processing uplink signals. A method is performed by a RRU (200). The method comprises obtaining uplink signals (S102) as received from wireless devices at antenna elements of an antenna array of the RRU (200), wireless device being associated with its own at least one user layer. The method comprises capturing (S104) energy per user layer by combining the received uplink signals from the antenna array for each user layer into combined signals, resulting in one combined signal per user layer. The combining for each individual user layer is based on channel coefficients of the wireless device associated with said each individual user layer. The method comprises providing (S106) the combined signals to a BBU (300).

Abstract: A method of operating a communication system is disclosed. The method includes forming a data frame having plural orthogonal frequency division multiplex (OFDM) symbols. A first set of preamble subcarriers is allocated to at least one of the OFDM symbols. A second set of data subcarriers is allocated to said at least one of the OFDM symbols.

Abstract: Various aspects of the present disclosure provide for methods, apparatus, and computer software for transmitting a common uplink burst in time division duplex (TDD) carriers. The common uplink burst includes a sounding reference signal (SRS) transmitted separate from (e.g., decoupled from) a demodulation reference signal (DM-RS). At least one symbol in the common uplink burst includes a control region for carrying control information and a data region for carrying data information. The SRS may be precoded separately from precoding of the control and data regions, so that the control and/or data information may be transmitted utilizing multiple input multiple output (MIMO).

Abstract: A switch component includes a common terminal, at least two selection terminals, a switching circuit that selectively connects the common terminal to each of the at least two selection terminals, and an inductor. One end of the inductor is connected to one of the at least two selection terminals. The switching circuit is integrated with the inductor.

Abstract: Communication network architectures, systems and methods for supporting a network of mobile nodes. As a non-limiting example, various aspects of this disclosure provide autonomous vehicle network architectures, systems, and methods for supporting a dynamically configurable network of autonomous vehicles comprising a complex array of both static and moving communication nodes. In particular, systems and methods for operating self-organized fleets of autonomous vehicles.

Abstract: Some techniques for implementing estimation of channel states with high accuracy and efficient feedback of the channel states in 3D MIMO are disclosed. One aspect of the present invention relates to user equipment for implementing 3D MIMO (3-Dimensional Multiple-Input Multiple-Output) communication, comprising: a channel state information generation unit configured to measure channel states of antenna ports of 3D MIMO antennas in a base station with reference signals transmitted from the antenna ports and generate channel state information based on the measured channel states; and a channel state information feedback unit configured to use different channel state information feedback means for antenna ports in respective dimensions of the antennas to feed the generated channel state information back to the base station.

Abstract: Exemplary embodiments include a computer-implemented method for configuring at least one antenna array comprising receiving a plurality of samples corresponding to signals incident on a plurality of antennas; using a computer arrangement, computing one or more data related to an envelope of the samples and estimating a direction of arrival of the signals incident on the antennas based on the one or more computed data; and configuring the at least one antenna array based on the estimated direction of arrival. The computing and estimating procedures can be performed for each of a plurality of direction-of-arrival candidates. The one or more data can be statistics corresponding to multipath shape factor parameters. The spatial selectivity of the at least one antenna array can be configured based on the estimated direction of arrival. Other exemplary embodiments include apparatus and computer-readable media embodying one or more of the exemplary computer-implemented methods and/or procedures.

Abstract: An example operation may include one or more of identifying, via a ledger validation thread, a corrupted data block that is stored within a chain of blocks on a distributed ledger, selecting a blockchain peer from among a plurality of blockchain peers that have access to the distributed ledger, and retrieving a replacement data block from the selected peer, determining whether the replacement data block is valid based on one or more of a previously stored validation block associated with the chain of blocks, and, in response to determining the replacement data block is valid, replacing the corrupted data block with the replacement data block on the distributed ledger.

Abstract: A transmitter and a receiver for communicating data using at least two separate RF channels using channel bundling. The transmitter includes a data stream partitioner configured to partition a data stream of data to be communicated into two or more stream partitions, two or more modulators configured to each receive a stream partition and to generate modulated data from the received stream partition, and an interleaver configured to assign the modulated data generated by a modulator from a received stream partition to different RF channels for transmission.

Abstract: Provided is a transmission parameter configuration method, information transmission method and terminal, and storage medium, including: configuring, by a base station, N basic transmission parameter sets, where N>1; transmitting M types of channels and/or signals by adopting the N basic transmission parameter sets, where N?M; determining, by a terminal, the N basic transmission parameter sets; selecting, according to reference information, a target basic transmission parameter set from the N basic transmission parameter sets, where the reference information includes a type of a channel or a signal to be transmitted, and/or blind-detected preamble sequence information, and/or a bandwidth, and/or the number of transmission layers, and/or the number of antenna ports; and transmitting the channel or the signal by adopting the target basic transmission parameter set which is selected.

Abstract: A material-discerning device is arranged to include an antenna, a proximity sensor, a band pass filter and a processor. The antenna radiates a radio-frequency signal and a material object is located in the field created by the antenna and near the proximity sensor. Change in the amplitude of the radio-frequency signal due to the presence of the material object is detected by the proximity sensor. The change in amplitude of the radio-frequency signal is stored. The frequency of the radio-frequency signal is changed and the process is repeated until a range of frequencies have been swept and stored. After the range of frequencies has been swept and stored, the processor determines the type of material of the material object using the results of the changes in amplitude of the radio-frequency signals.

Abstract: The present disclosure relates to a foreign object detection method of a wireless power transmitter, and the method may include acquiring the frequency characteristics of a current flowing through a coil within the wireless power transmitter, comparing a peak frequency with a resonant frequency, and detecting whether or not the foreign object is placed on the transmitter through the comparison. In addition, the present disclosure relates to an interference avoidance method of a wireless power transmitter, and the method may include connecting a head unit of an automobile in a wireless manner through a communication device, receiving a first signal for avoiding interference from the head unit to stop wireless charging or change a first frequency band to a second frequency band, and receiving a second signal from the head unit to resume the wireless charging or change to the first frequency band.

Abstract: A method for operating a transmitting node of a wireless communication network. The transmitting node includes or is connected to an antenna array having multiple antenna elements. A signal indication indicating a first and/or reference signaling is obtained. The first reference signaling includes transmission on a first plurality of disjunct frequency bands, and the second reference signaling includes transmission on a second plurality of disjunct frequency bands. The first reference signaling and the second reference signaling are transmitted based on a signal map of the first and the second reference signaling to antenna elements of the antenna array.

Abstract: Techniques are described for wireless communication at a wireless communication device. A determination may be made regarding the number of receive chains, of a plurality of receive chains, to enable for a channel. Power to the receive chains may be regulated based on the determined number of enabled receive chains. The determination may be based on a transmission scheduling rate for the wireless communication device and a rank for the channel. In some examples, the determination may further be based on a channel quality of the channel and/or a type of traffic scheduled for the channel.

Abstract: A feedback control system for data transmissions in voice activated data packet based computer network environment is provided. A system can receive audio signals detected by a microphone of a device. The system can parse the audio signal to identify trigger keyword and request. The system can select a content item using the trigger keyword or request. The content item can be configured to establish a communication session between the device and a third party device. The system can monitor the communication session to measure a characteristic of the communication session. The system can generate a quality signal based on the measured characteristic.

Abstract: Certain cellular communication systems may use beamforming to create distinct signal beams in different radial directions relative to a base station. Upon receiving a request for the location of a mobile device, a position calculation function is used to calculate the location of the mobile device based on multiple types of location-related data. The location-related data may indicate the direction of the directional signal beam that is currently being used for communications between the mobile device and a base station. The direction may be used in conjunction with other location-related data, such as distance information, to estimate the location of the mobile device.

Abstract: A filter circuit may include a first path having a first complex baseband filter. The circuit may further include a second path having a second complex baseband filter. The circuit may further include a combiner coupled to an output of the first complex baseband filter and an output of the second complex baseband filter.

Abstract: Embodiments of the present invention provide a receiver and a data receiving method. The receiver includes: two first input ends, configured to receive a digital signal of an X-polarization state and a digital signal of a Y-polarization state; a despreading module, configured to despread the digital signal of the X-polarization state and the digital signal of the Y-polarization state based on N delay values and spreading codes of N transmitters, to obtain N first baseband signals and N second baseband signals; and a multiple-input multiple-output equalization module, configured to perform equalization filtering processing on the N first baseband signals and the N second baseband signals, to obtain recovered data of the first polarization states and recovered data of the second polarization states of the N transmitters. In the embodiments of the present invention, the coherent CDMA multipoint-to-point data transmission in an optical communications system is implemented.

Abstract: The method is performed in a radio network node and comprises the steps of: obtaining antenna data affecting transmission weights applied for each individual antenna of the plurality of antennas; obtaining an intermediate power value based on a sum of signals from couplers provided by each antenna of the plurality of antennas; determining a power factor based on the antenna data; and calculating the total radiated power based on the intermediate power value and the power factor.

Abstract: A tunable filter reduces the total number of filters used in TDD (Time-Division Duplex) communication circuitry. The communication circuitry may include a tunable filter and a first switch associated with the tunable filter. The tunable filter may include a tuning component and a filtering component. The tuning component may be located with the first switch on a first die. The filtering component may be located in a laminate underneath the first switch. Power amplifiers for amplifying transmission signals may be located on a second die, and the second die may be located on the laminate.

Abstract: The disclosed systems and methods for conducted massive MIMO array testing uses an efficient method of utilizing hardware resources for emulating signals from a massive MIMO base station transceiver to a MIMO mobile unit as dictated by a channel model; and also for emulating signals from a MIMO mobile unit to a massive MIMO BS transceiver, as dictated by a channel model. The system uses a phase matrix combiner to emulate the angular behavior of the propagation using virtual probes, combined with a radio channel emulator to create the temporal, multipath, and correlation behavior of the propagation. Using a phase matrix function increases the number of antenna elements that can be utilized in a massive MIMO array emulation while keeping the required number of fading channels within the radio channel emulator at a reduced number, thus forming a cost effective, yet realistic test system for massive MIMO testing.

Abstract: A smart antenna is provided, which may include a plurality of antenna units and a controller. The controller may be coupled to the antenna units. The controller may scan an angle range by a first angle interval according to a characteristic vector of the antenna units and an initial angle; if the power change between any two adjacent scanning points is negative, the controller may multiply the first angle interval by a number to generate a second angle interval, and keep scanning the angle range by the second angle interval; when the controller completely scans the angle range or the power change between any two adjacent scanning points is positive, the controller may generate a power spectrum.

Abstract: A radio frequency identification (RFID) system for frequency multiplexing includes, in an exemplary embodiment, an RFID interrogator configured for generating an RFID signal, wherein a channel frequency of the RFID signal changes over time; at least one antenna or transmission line; and a diplexer coupling the RFID interrogator and the antennas or transmission lines and configured for distributing the RFID signal to each of the antennas or transmission lines, respectively, depending on the channel frequency of the RFID signal generated. The antennas or transmission lines are configured to transmit an electromagnetic wave in response to and at the channel frequency of the RFID signal distributed thereto. Other embodiments include RFID systems and methods including a frequency selective surface and both similar and different components and aspects for frequency multiplexing.

Abstract: A high-frequency signal processing apparatus and a wireless communication apparatus can achieve a decrease in power consumption. For example, when an indicated power level to a high-frequency power amplifier is equal to or greater than a second reference value, envelope tracking is performed by causing a source voltage control circuit to control a high-speed DCDC converter using a detection result of an envelope detecting circuit and causing a bias control circuit to indicate a fixed bias value. The source voltage control circuit and the bias control circuit indicate a source voltage and a bias value decreasing in proportion to a decrease in the indicated power level when the indicated power level is in a range of the second reference value to the first reference value, and indicate a fixed source voltage and a fixed bias value when the indicated power level is less than the first reference value.

Abstract: A wireless transceiver device includes an operation amplification circuit, a transmitter circuit, a receiver circuit, and a transceiver control circuit. The operation amplification circuit, according to a rate parameter and a filtering parameter, filters and amplifies an input signal and outputs a processed signal. The transmitter circuit selectively uses a first ratio or second ratio as the amplification parameter, converts an input signal into an analog signal, inputs the analog signal into the operation amplification circuit, mixes the processed signal with a local oscillating frequency and then output an output signal. The receiver circuit mixes an external signal with another local oscillating frequency, inputs the mixed signal into the operation amplification circuit, and converts the processed signal into a digital signal. The transceiver control circuit selectively and electrically connects the operation amplification circuit with the transmitter circuit or the receiver circuit.

Abstract: Systems and methods for improving operational efficiency of a radio frequency system, which includes an antenna amplifier unit that amplifies a data stream while the data stream is being wirelessly communicated and another antenna amplifier unit that amplifies another data stream while the other data stream is being wirelessly communicated. The radio frequency system includes a transceiver amplifier unit coupled to the antenna amplifier unit via an electrical connector, in which the transceiver amplifier unit amplifies the data stream while the data stream is being wirelessly communicated, another transceiver amplifier unit coupled to the other antenna amplifier unit via another electrical connector, in which the other transceiver amplifier unit amplifies the other data stream while the other data stream is being wirelessly communicated, and an electrical connector switching device coupled between antenna-sides of the electrical connector and the other electrical connector.

Abstract: Disclosed are a power supply method, device and system. The method includes that: a working state of a terminal in a home network is detected, herein, the terminal accesses the home network through a coaxial cable; and power supply to optical access equipment is controlled according to the working state, herein, the optical access equipment is arranged to implement access of a passive optical fiber network to the home network.

Abstract: Switched-filter duplexing architecture for front-end systems. In some embodiments, a wireless architecture can include a first system having a first signal routing circuit for a first transceiver, and a first antenna node, and be configured to be capable of simultaneous transmit and receive operations for a first band and a receive operation for a second band through the first antenna node. The wireless architecture can further include a second system having a second signal routing circuit for a second transceiver and a second antenna node, and be configured to be capable of a transmit operation for the second band through the second antenna node. The wireless architecture can further include a switchable path implemented to selectively allow the transmit operation for the second band to be performed through the second antenna node of the second system or the first antenna node of the first system.

Abstract: The present invention relates to a method for efficiently supporting communication for vehicles in a next-generation wireless communication system and a device for the same. To this end, a user equipment (UE) receives signals from a network through a plurality of antenna units which are located in dispersed locations of the UE, determines, through a central unit thereof, whether a mobility related event of the UE has occurred through the signals received through the plurality of antenna units and transmits an event occurrence report to the network when the mobility related event of the UE has occurred, wherein whether the mobility related event of the UE has occurred is determined in consideration of receive (Rx) power of the signals received through the plurality of antenna units and a ray distribution between the network and the UE.

Abstract: Methods and apparatus for multiplexing reference signals for Multiple Input Multiple Output (MIMO) layers are provided. Resources for Demodulation Reference Signals (DMRS) corresponding to each of two or more data streams are assigned, wherein the resources assigned to each of the data streams are staggered in frequency and span two or more OFDM (Orthogonal Frequency Divisional Multiplexing) symbols. The DMRS is transmitted using the assigned resources.

Abstract: A non-line of sight backhaul system and method are described that provides self-alignment of the antennas beams of the wireless radios of the system, that provides robust operation in licensed and unlicensed frequency bands, that facilitates the use of a reduced number of frequency channels from M to 1 and that enables operation in a non-line of sight (NLOS) propagation environment.

Abstract: An envelope tracking (ET) circuit is provided. In the ET circuit, a number of amplifier circuits are configured to amplify a radio frequency (RF) signal simultaneously to generate multiple RF transmit signals for transmission in a formed RF beam. The RF signal is pre-modulated into respective phase and amplitude terms such that the multiple RF transmit signals can be linearly combined at a receiver(s). A signal processing circuit is configured to determine a combined distortion term in the multiple RF transmit signals. Accordingly, the signal processing circuit pre-distorts the RF signal with a distortion correction term to offset the combined distortion term in the RF transmit signals. By introducing the distortion correction term in the RF signal, it is possible to restore linear coherency among the RF transmit signals without compromising efficiency and/or increasing heat dissipation of the amplifier array(s).

Abstract: A feedback control system for data transmissions in voice activated data packet based computer network environment is provided. A system can receive audio signals detected by a microphone of a device. The system can parse the audio signal to identify trigger keyword and request. The system can select a content item using the trigger keyword or request. The content item can be configured to establish a communication session between the device and a third party device. The system can monitor the communication session to measure a characteristic of the communication session. The system can generate a quality signal based on the measured characteristic.

Abstract: Embodiments described herein methods and systems for channel correlation based user detection in an uplink multiuser transmission of a multiple-input multiple-output (MIMIO) network. In some embodiments, the channel correlation based user detection may be used in 802.11 UL MUMIMO systems. For example, an access point may detect whether a client station responds to a trigger frame and then adjust a channel matrix accordingly to reflect whether the client station is responsive. The access point may then decode received data signals based on the adjusted channel matrix that reflects whether a client station has transmitted.

Abstract: Communication network architectures, systems and methods for supporting a network of mobile nodes. As a non-limiting example, various aspects of this disclosure provide autonomous vehicle network architectures, systems, and methods for supporting a dynamically configurable network of autonomous vehicles comprising a complex array of both static and moving communication nodes. In particular, systems and methods for operating self-organized fleets of autonomous vehicles.

Abstract: A radio-frequency module utilizing carrier aggregation includes a switch circuit that includes one input terminal and three or more output terminals and that simultaneously connects the input terminal and each of two or more output terminals selected from the output terminals, signal paths that propagate signals of corresponding frequency bands, band pass filters in the signal paths, and variable matching circuits in the signal paths. The circuit states of the variable matching circuits are changed in accordance with a combination of two or more signal paths simultaneously connected to the input terminal.

Abstract: Applications of CI processing to ad-hoc and peer-to-peer networking significantly improve throughput, network capacity, range, power efficiency, and spectral efficiency. CI-based subscriber units perform network-control functions to optimize network performance relative to channel conditions, network loads, and subscriber services. CI codes are used to identify and address network transmissions. Channel characteristics of communication links are employed to encode, address, and authenticate network transmissions. CI transceivers used as relays and routers employ unique characteristics of transmission paths to code and decode network transmissions. A central processor is adapted to perform array processing with signals received from, and transmitted by, a plurality of subscriber units in a wireless network.

Abstract: The present disclosure describes methods and apparatuses for matrix compensation to prevent rank deficiency. In some aspects, a channel matrix is formed based on channel feedback matrices that are received from multiple devices. The channel matrix is transformed to provide a channel covariance matrix, which is then decomposed into a unitary matrix and Eigen value matrix components. Diagonal values of the Eigen value matrix are increased to provide a compensated Eigen value matrix. Based on the compensated Eigen value matrix, a steering matrix is determined for steering transmissions through the channel to the multiple devices. By compensating the Eigen value matrix, rank deficiency issues that typically result in failed steering matrix calculations can be prevented. Alternately or additionally, a dynamic range of the steering matrix calculations may be reduced by compensating matrices, enabling steering matrices to be calculated with less-complex or fewer hardware resources.

Abstract: A method for communicating with a plurality of communication devices (UEs) using a phased array antenna system including an array of antenna elements, the method involving: receiving a plurality of port signal streams, wherein the plurality of port signal streams was obtained by precoding a plurality of data streams, each data stream of the plurality of data streams intended for a different corresponding UE; and within the phased array antenna system, processing the plurality of port signal streams to (1) undo the precoding that was performed on the plurality of data streams, and (2) generate via the array of antenna elements a plurality of transmit beams, wherein each transmit beam is directed towards a corresponding different UE among the plurality of UEs and carries a corresponding transmit signal that is derived exclusively from the data stream among the plurality of data streams that is intended for that UE.

Abstract: In performing SVD-MIMO transmission, a set-up procedure is simplified while assuring a satisfactory decoding capability with a reduced number of antennas. A transmitter estimates channel information based on reference signals sent from a receiver, determines a transmit antenna weighting coefficient matrix based on the channel information, calculates a weight to be assigned to each of components of a multiplexed signal, and sends, to the receiver, training signals for respective signal components, the training signals being weighted by the calculated weights. On the other hand, the receiver determines a receive antenna weighting coefficient matrix based on the received training signals.

Abstract: Antennas and MIMO antenna arrays in a housing of an electronic device are described. The MIMO antenna array includes a plurality of antennas. At least one of the antennas has operating frequency ranges of 700 MHz-900 MHz, 1700 MHz-2100 MHz, and 3 GHz-5 GHz. The MIMO antenna array may include 8 or 10 antennas.

Abstract: A method for a cellular telecommunications network includes selecting first and second source cells that are co-sited cells associated with first and second antennas, respectively, identifying first neighbor cells of the first cell and second neighbor cells of the second cell, determining that an antenna feed for the second cell is feeding the first antenna by comparing locations of the first neighbor cells to a pointing direction of the first antenna.

Abstract: Multiple antennas at the receiver and/or transmitter are commonly used in wireless communications systems to provide diversity in order reduce fading and other effects brought about by multi-path propagation. Due to the size of hearing aids and the wavelengths of the frequencies used for communication, it is difficult to achieve what is called spatial diversity by disposing the multiple antennas at different locations. Described herein are techniques for providing polarization diversity in hearing aids using antennas with different polarizations and applying the appropriate phase shifts to the received and/or transmitted signals to improve the signal quality.

Abstract: The disclosed systems and methods for conducted massive MIMO array testing uses an efficient method of utilizing hardware resources for emulating signals from a massive MIMO base station transceiver to a MIMO mobile unit as dictated by a channel model; and also for emulating signals from a MIMO mobile unit to a massive MIMO BS transceiver, as dictated by a channel model. The system uses a phase matrix combiner to emulate the angular behavior of the propagation using virtual probes, combined with a radio channel emulator to create the temporal, multipath, and correlation behavior of the propagation. Using a phase matrix function increases the number of antenna elements that can be utilized in a massive MIMO array emulation while keeping the required number of fading channels within the radio channel emulator at a reduced number, thus forming a cost effective, yet realistic test system for massive MIMO testing.

Abstract: The present invention discloses a signal processing method, apparatus, and system. In M user equipments, an active set Ki and an interference set K?i of a user equipment i are determined according to power measurement values from the user equipment i to N sites; for the active set Ki of the user equipment i, superposition of sent signals of all other user equipments j of all active sites ki are cancelled out with each other, to obtain one constraint condition of a weight, and for the M user equipments, M constraint conditions are obtained, and a weight subspace T is determined; and one weight is determined in the weight subspace according to an interfering signal of another user equipment j for the user equipment i in the interference set K?i of the user equipment i and a wanted signal of the user equipment i in the active set Ki of the user equipment i.

Abstract: A method for transmitting data includes grouping resource elements (REs) of orthogonal frequency division multiplexed (OFDM) symbols of a physical resource block (PRB) into at least one paired RE and at least one orphan RE, transmitting the at least one paired RE in accordance with space frequency block coding (SFBC), and transmitting the at least one orphan RE in accordance with a precoder.

Abstract: A radio transmission station gives beamforming weights to electrical signals to control directions of radio-wave beams emitted from transmitting antennas. The radio transmission station generates a beam-discovery signal (BDS) that enables a radio reception station, after the radio reception station receives the beams, to identify the directions of the beams, and emits the BDS beams in multiple directions. The radio transmission station determines, based on at least one of the surroundings of the radio transmission station and a situation of the radio reception station, an arrangement pattern of multiple resource points to which the BDS is mapped. Based on information that is reported from the radio reception station and indicates a suitable direction among the directions of the beams, the radio transmission station determines a suitable beamforming weight that is to be given to a data signal addressed to the radio reception station.

Abstract: In order to transmit a large amount of data in series at a time with a MIMO communication scheme while avoiding deterioration of decoding characteristics due to change over time by a channel matrix, a wireless communication system uses an open-loop type and a closed-loop type of MIMO communication modes in combination and switches to the open-loop MIMO communication mode in response to the information that the amount of data to be transmitted at a time has exceeded a predetermined amount of bits or a predetermined transmission time during data transmission under the closed-loop MIMO communication mode. By discontinuing useless closed-loop MIMO communication and switching to the open-loop MIMO communication mode that is better than Zero-forcing, the decoding characteristics are prevented from simply becoming deteriorated.