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: Embodiments of the present invention provide a method for controlling power of a carrier signal, user equipment, and a base station. The method includes: receiving, by user equipment, power control parameters, sent by at least one base station, of at least two carrier signals, where the at least two carrier signals are signals sent on at least two aggregation carriers; determining, by the user equipment according to the power control parameters, channel gain reference quantities corresponding to the at least two carrier signals, where the channel gain reference quantities are used to represent a magnitude of a channel gain; and controlling, by the user equipment, power of the at least two carrier signals according to the channel gain reference quantities. According to the technical solutions of the present invention, a power resource of user equipment can be effectively utilized, and network performance can be improved.

Abstract: This disclosure relates generally to radio frequency (RF) front-end circuitry for different types of carrier aggregation, along with methods of operating the same. In one embodiment, the RF front-end circuitry includes a first diplexer, a second diplexer, first antenna selection circuitry, and second antenna selection circuitry. In order to maintain adequate isolation between high bands and low bands but provide carrier aggregation, the first antenna selection circuitry is configured to selectively couple each of a first plurality of RF ports to any one of a first low band port in the first diplexer and a second low band port in the second diplexer, while the second antenna selection circuitry is configured to selectively couple each of the second plurality of RF ports to any one of a first high band port in the first diplexer and a second high band port in the second diplexer.

Abstract: Disclosed herein are methods and systems that can help to more effectively select a cooperating set of cells for coordinated multipoint (CoMP) service. One illustrative method involves: (a) determining a donor status of a first base station that serves a first cell, wherein the donor status indicates whether or not the first base station is configured as a donor base station for at least one relay node, and (b) based at least in part on the determined donor status of the first base station, determining whether or not to include the first cell in a CoMP cooperating set.

Abstract: A method, an apparatus, and a computer-readable medium for wireless communication are provided. In one aspect, the apparatus is configured to determine a power control command including a target receiver power level for uplink transmission. The apparatus is configured to transmit a frame to a wireless device. The frame may include information associated with the determined target receiver power level for uplink transmission from the wireless device and a transmit power level at which the frame is to be transmitted. The information may enable the wireless device to compute a transmit power for the uplink transmission. The frame may include power control commands for other wireless devices.

Abstract: Communications systems, methods and devices having improved noise immunity are disclosed. In one embodiment, a method for improving noise immunity in a communication may include (1) at least one computer processor determining a region of interest in a received signal; (2) the at least one computer processor determining a surrogate candidate within the region of interest of the signal; and (3) the at least one computer processor encoding the surrogate candidate as a surrogate in a region of the signal other than the region of interest.

Abstract: An adapter (10) comprises a single adapter output (45) connectable to at least one antenna line device (100a-c), at least two base station inputs (30a-c), the at least two base station inputs (30a-c) being individually connectable to a base station (110a-c) or a primary control device (460c) and at least one microcontroller (40a-c), the microcontroller (40a-c) being connected between one of the base station inputs (30a-c) and the single adapter output (45). An antenna system (5) comprising such an adapter (10) and a plurality of antenna line devices (100a-c) connected to the single adapter output (45) of the adapter is also disclosed. A method for operating the radio antenna (10) having a plurality of antenna line devices (100a-c) from at least two base stations (110a-c) is disclosed.

Abstract: A particular communications protocol is used for antenna training to accomplish directional communications in a wireless communications network. In some embodiments, pertinent information for various requests, responses, and status reports, is included in information elements.

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 movable radio base station, M-RBS, configured to provide to a plurality of user equipments wireless access to a telecommunications network is changed from a first mode to a second mode that is different from the first mode. Each of the first mode and the second mode specifies a set of parameter values for operating parameters of the M-RBS.

Abstract: Exemplary embodiments described herein include systems, methods, and nodes for determining a frequency band for wireless backhaul. It may be determined that a utilization of a frequency band used for backhaul between a relay wireless device and an access node meets a criteria. An overhead may be calculated for a set of frequency bands available for use as backhaul between the relay wireless device and the access node, wherein the calculated overhead for a particular one of the set of frequency bands is based on at least one of a number of wireless devices that use the particular frequency band for carrier aggregation and a number of wireless devices that receive a beamformed signal over the particular frequency band. One of the set of frequency bands may be selected based on the calculated overhead. And the relay wireless device may be instructed to communicate wireless backhaul to the access node over the selected frequency.

Abstract: The present disclosure relates to a pre-5th-Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4th-Generation (4G) communication system such as Long Term Evolution (LTE). A method for operating a terminal in a wireless communication system comprises transmitting, to a base station, at least one reference signal through at least one first transmission beam and if ACK information for the at least one reference signal is received from the base station, transmitting, to the base station, the at least one reference signal through at least one second transmission beam. A width of the at least one second transmission beam is greater than a width of the at least one first transmission beam.

Abstract: A system comprises a modulator circuit, a test signal generator circuit, and a control circuit. The modulator circuit is operable to generate a data-carrying signal based on a reference signal. The test signal generator circuit is operable to generate a test signal based on the reference signal. The control circuit is operable to determine current status of a microwave backhaul link. The control circuit is operable to configure a nominal frequency at which the test signal generator circuit generates the test signal based on the determined status of the microwave backhaul link. The control circuit is operable to determine an amount of whitespace to have on either side of the test signal based on the current status of the microwave backhaul link. The control circuit is operable to configure the modulator circuit such that the data-carrying signal has the determined amount of whitespace surrounding the nominal frequency of the test signal.

Abstract: A calibration system, in a receiver chip, receives a plurality of receive signals at a plurality of receive paths. A first receive path and a second receive path is selected for a first receive signal and a second receive signal, respectively. A first signal parameter of the second receive signal is adjusted relative to the first signal parameter of the first receive signal to maximize a first signal strength value of an added signal or minimize a second signal strength value of a subtracted signal. Based on the adjusted first signal parameter, an offset of the first signal parameter is calibrated. Further, based on a matching of the second signal parameter in the second receive path relative to the second signal parameter in the first receive path, value of the second signal parameter is calibrated.

Abstract: Antenna switching circuitry includes an antenna node, a number of signal path nodes, and a number of switching elements. Each one of the switching elements is coupled between a different one of the signal path nodes and the antenna node. At least two of the signal path nodes are coupled together in order to form a low distortion node, such that the switching elements between the low distortion node and the antenna node are used to pass a low-distortion radio frequency (RF) signal. By coupling two of the signal path nodes together, a low distortion signal path is created to the antenna. Creating a low distortion signal path using multiple switching elements allows for the size of the switching elements to remain small, which reduces the parasitic capacitance of each one of the switches and therefore the insertion loss of the antenna switching circuitry.

Abstract: A portable communication device includes an appearance, a substrate and a switchable resonant antenna. The substrate is disposed in the appearance, and the substrate has a ground plane. The switchable resonant antenna comprises a first connection portion, a switching unit, a first metal element and a second metal element, where the first connection portion is electrically coupled between the ground plane and the switching unit, the switching unit is configured to electrically couple the first connection portion to the first metal element or the second metal element according to a control signal generated corresponding to a detecting result, in order to generate a first resonant mode.

Abstract: A communication apparatus detects a communication partner apparatus and transmits a first signal. Then, in the case where the partner apparatus is detected and a response to the transmitted first signal has not been received from the partner apparatus, the communication apparatus transmits a second signal having a higher power level than the first signal.

Abstract: Methods, systems, and devices for wireless communication are described. An access point (AP) transmits instructions to quiet a dynamic frequency selection (DFS) home channel for a period of time. Instructions can include a quiet information element (IE) or a clear-to-send to self (CTS2Self) frame. The AP then allocates a first dedicated RF chain to a first media access control (MAC) component and a second dedicated RF chain, separate from the first dedicated RF chain, to a second MAC component of the access point. The allocation can include reducing the number of RF chains dedicated to the first MAC component. During the time period determined by the instructions, the first dedicated RF chain scans the home DFS channel and the second dedicated RF chain scans at least one other channel (e.g., based at least in part on the time period and channel scan priority) in the same band as the DFS home channel.

Abstract: Disclosed are methods and systems for selecting a carrier on which to serve a user equipment device (UE). In particular, a base station may determine that a speed of movement of the UE is threshold high. In response to determining that the speed of movement of the UE is threshold high, the base station may select a carrier based on a group delay variation (GDV) of the selected carrier. For example, the base station may respond to the determining by selecting a carrier having a threshold low GDV. In another example, the base station may respond to the determining by selecting the carrier having the lowest GDV among two or more candidate carriers being considered as part of the selection process. As such, once a carrier is selected, the base station may then serve the UE on the selected carrier.

Abstract: An electronic device is provided. The electronic device includes a plurality of antennas and a communication circuit configured to electrically connect with at least one of the plurality of antennas, wherein the communication circuit is configured to obtain information of a level of a transmit power and transmit a signal based on a designated antenna among the plurality of antennas if the level of the transmit power is less than a level, determine an antenna for signal transmission among the plurality of antennas if the level of the transmit power is greater than or equal to the level, and perform an antenna switching operation of selecting the determined antenna.

Abstract: The present application discloses an antenna function extension apparatus, device, and method. The apparatus includes a control unit, a storage unit, an antenna identification unit, a modulation and demodulation unit, a power supply unit, a peripheral connection unit, a radio frequency (RF) channel, a first transceiver unit, and a second transceiver unit. The control unit is separately connected to the storage unit, the antenna identification unit, the peripheral connection unit, and the modulation and demodulation unit. The first transceiver unit is connected to the antenna identification unit. The second transceiver unit is separately connected to the modulation and demodulation unit, the power supply unit, and the peripheral connection unit.

Abstract: Systems and methods for wireless communications are disclosed. More particularly, aspects of the present disclosure generally relate to techniques for wireless communications by a first apparatus comprising obtaining, via at least first and second receive antennas having different polarizations, first and second training signals transmitted from a second apparatus via at least first and second transmit antennas having different polarizations, determining, based on the first and second training signals, one or more characteristics for different transmit-receive antenna pairs, each pair comprising one of the first or second transmit antennas and one of the first or second receive antennas, and generating, based on one or more characteristics, a parameter indicative of whether a link path between the first and second apparatuses is line of sight (LOS).

Abstract: RF front-end circuitry arranged to provide for RF Multiple-Input and Multiple-Output (MIMO) signals is disclosed. In one embodiment, the RF front-end circuitry may include an antenna port, a first multiple throw (MT) switch, and a second MT switch. The first MT switch is configured to selectively couple a first pole port to any one of a first set of throw ports, and the second MT switch is configured to selectively couple a second pole port to any one of a second set of throw ports. The first pole port of the first MT switch is coupled to the antenna port. More than one of the second set of throw ports of the second MT switch are coupled to transmit one or more receive MIMO signals to RF transceiver circuitry. Accordingly, the RF front-end circuitry routes receive MIMO signals from the antenna port to the RF transceiver circuitry.

Abstract: A method of performing a beamforming in a base station of a wireless communication system according to one embodiment of the present invention may include determining an effective range of an analog beam based on a gain of an analog beamforming in a hybrid beamforming, determining a precoding matrix for a digital beamforming in the hybrid beamforming based on the effective range of the analog beam, and performing the hybrid beamforming having the digital beamforming and the analog beamforming coupled therein based on the effective range and the precoding matrix.

Abstract: A method for the multiple beamforming training and an apparatus using the same are provided. An initiator determines a candidate sector to be used for a transmission during a sector sweep. After the initiator exchanges with a responder an information request frame and an information response frame about the multiple beamforming training through the candidate sector, the responder performs a plurality of beam refinement protocol (BRP) processes using a plurality of polarized channels through the candidate sector.

Abstract: Apparatuses and methods are disclosed that may perform ranging operations between an initiator device and a responder device. The initiator device may request the responder device to perform a ranging operation. The responder device may transmit a first fine timing measurement (FTM) frame to the initiator device, may receive an acknowledgement (ACK) frame from the responder device, and may transmit a second FTM frame to the initiator device. The second FTM frame may include a time value and angle information. The time value may indicate a difference between a time of departure (TOD) of the first FTM frame and a time of arrival (TOA) of the ACK frame. The angle information may indicate a direction of the initiator device relative to the responder device. The initiator device may determine its position, relative to the responder device, based at least in part on the received time value and angle information.

Abstract: Apparatus and method for communicating control data indicative of the capability of RF receiver equipment in wireless telecommunications devices. The control data is then used to allocate transmission resources to the telecommunications devices (including MTC-type terminals). Where a virtual carrier is established to carry data for a given MTC-type device, the position of the center frequency for that virtual carrier is assigned on the basis of both the capability of the RF receiver equipment of that terminal and the degree of traffic congestion on the frequency band at which the virtual carrier has been established.

Abstract: A broadcast signal transmitter is provided that includes an Forward Error Correction (FEC) encoder configured to error correction process Physical Layer Pipe (PLP) data; a bit interleaver configured to bit interleave the PLP data; a framer configured to generate a signal frame comprising the PLP data, the signal frame comprising a preamble and at least one subframe; a pilot inserter configured to insert Scattered Pilots (SPs) into the signal frame; and an Inverse Fast Fourier Transform (IFFT) modulator configured to perform Orthogonal Frequency Division Multiplexing (OFDM)-modulation on the signal frame. An SP pattern of the SPs is defined by Dx and Dy, the Dx being a separation of pilot bearing carriers in a frequency direction and the Dy being a number of symbols forming one scattered pilot sequence in a time direction. The amplitude of the SPs is determined from a SP boosting parameter and the SP pattern of the SPs.

Abstract: Certain aspects of the present disclosure relate to techniques and apparatus for estimating a distance between a first and second apparatus. For example, the first apparatus may obtain a plurality of training signals received in a plurality of directions from a second apparatus and estimate, based on the plurality of training signals, a distance between the first apparatus and the second apparatus. In certain aspects, the distance may be estimated based on a ratio of receive powers of first and second training signals of the plurality of training signals.

Abstract: Aspects of a method and system for scheduling multiple concurrent transmissions during a contention access period in a wireless communications network are presented. Aspects of the system comprise communicating devices (DEVs) within a piconet that are operable to derive a neighborhood map of a piconet. The neighborhood map information may enable a plurality of DEVs to concurrently transmit signals during a given channel time allocation (CTA) time slot. The ability for multiple DEVs to transmit signals concurrently during a single CTA time slot may increase spectral reuse within a wireless communication medium. In another aspect the system, the neighborhood map information may enable individual DEVs to set clear channel assessment (CCA) thresholds. Individual DEVs may utilize CCA threshold information to determine when to transmit signals to one or more destination DEVs and/or at what rate to transmit data via the signals.

Abstract: Apparatuses and methods are disclosed that may perform ranging operations between an initiator device and a responder device. The initiator device may request the responder device to perform a ranging operation. The responder device may transmit a first fine timing measurement (FTM) frame to the initiator device, may receive an acknowledgement (ACK) frame from the responder device, and may transmit a second FTM frame to the initiator device. The second FTM frame may include a time value and angle information. The time value may indicate a difference between a time of departure (TOD) of the first FTM frame and a time of arrival (TOA) of the ACK frame. The angle information may indicate a direction of the initiator device relative to the responder device.

Abstract: Disclosed is a method and system for compensating excessive delay spread in uplink coordinated multipoint service. An uplink data-unit transmitted by a user equipment device (UE) on a first uplink air interface to a first base station (BS) using a first group of sub-carrier frequencies may be received at a time that is within an alignment-time range for simultaneously decoding uplink data-units from UEs transmitting on the first uplink. A determination is made that the uplink data-unit transmitted simultaneously by the UE on a second uplink air interface using a second group of sub-carrier frequencies will be received at a second BS at a time that is time is beyond the alignment-time range for simultaneously decoding uplink data-units from UEs transmitting on the second uplink. Decoding of the received uplink data-unit at the second BS is then delayed until a start time beyond the end of the alignment-time range.

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.