244 results about "Zero force" patented technology

A multi-user MIMO downlink beamforming system (200) is provided to enable transmit beamforming vectors to be efficiently provided to a subset of user equipment devices (201.i), where spatial separation or zero-forcing transmit beamformers (w_i) are computed at the base station (210) and used to generate precoded reference signals (216). The precoded reference signals (216) are fed forward to the user equipment devices (201.i) which apply one or more hypothesis tests (207.i, 208.i) to the precoded reference signals to extract the precoding matrix (W), including the specific transmit beamforming vector (w_UE) designed for the user equipment, and this extracted information is used to generate receive beamformers (v_i).

A multi-user MIMO downlink beamforming system with limited feed forward (200) is provided to enable preceding matrix information to be efficiently provided to a subset of user equipment devices (201.i), where zero-forcing transmit beamformers (w_i) are computed at the base station (210) and assembled into a precoding matrix (W). The precoding matrix is encoded using a compact reference signal codebook (225, 207.i) for forward link signaling, either by sending bits indicating the index of the transmission matrix used, or by transmitting one or more precoded pilots or reference signals wherein the pilot signals are precoded using vectors uniquely representative of the transmission matrix used which includes candidate reference signal matrices which meet a predetermined condition number requirement, such as a condition number threshold. The preceding matrix information (227) is extracted at the user equipment devices (201.i) using the compact reference signal codebook (207.i) and used by the MMSE receiver (209.i) to generate receive beamformers (v_i).

Various x-y input devices are disclosed that are adapted to allow a user to hold and operate the input device with a stress-reducing, open grip posture with the thumb pointing forward and on top of the device. One preferred embodiment discloses an input device for a computer comprising an x-y input sensor (such as a touchpad) positioned perpendicular to the thumb such that the user provides input with the thumb tip by using pivotal movement of the thumb. Various stress-reducing zero force touch switches are disclosed including zero force touch switches that can be adjusted to accommodate variations in user finger length. The mode of x-y cursor control can be altered through the use of x-y input sensor perimeter inputs. One preferred embodiment discloses a thumb actuated scroll select touch switch that alters the response to actuation of the finger actuated zero force touch switches from mouse button input to scroll wheel input. A unique fin-shaped feature of one preferred embodiment stabilizes the device within the relaxed hand and adapts the device to fit a range of user hand sizes.

A heat sink in a heat transfer relationship with a substrate such as an integrated chip, chip carrier, or other electronic package. The heat sink is connected to a frame which is connected to a printed circuit board or other suitable support on which the substrate is positioned. The heat sink, which extends through an aperture in the frame is coupled to a surface of the substrate. The heat sink is mechanically decoupled from the substrate. Large heat sinks may be thermally connected to surface mount substrates mounted using technologies such as ceramic ball or column grid arrays, plastic ball or column grid arrays, or solder balls or columns. The heat sink is attached coaxially through the aperture to the substrate. After assembly and lead/tin or other metallic surface mount interconnects are relaxed such that the substrate and is completely supported by the frame and the heat sink imparts zero or nearly zero downward force. Because the heat sink moves freely within the aperture during assembly, the heat sink package is useful for a variety of different substrates. Preferably, the frame is a plate and a plurality of studs. The plate material are selected to match the thermal expansion of the underlying support, and the stud material matched the thermal expansion of the substrate. Thus, the frame construction allows matching expansion and contraction of the assembly to the underlying substrate and support.

Detection for a MIMO (multiple-input, multiple-output) wireless communications system with symbols iteratively detected in subsets with maximum likelihood hard decisions within subsets. Previously detected subsets of symbols are used to regenerate corresronding input signals for interference cancellation. With a 4-transmitter antenna, 4-receiver antenna system, two subsets of two symbols are possible with the first two symbols detected with zero-forcing or MMSE soft estimates which feed maximum likelihood hard decisions; and the hard decision for the first two symbols are used for interference cancellation followed by zero-forcing or MMSE soft estimates for the second two symbols which then feed further maximum likelihood hard decisions.

The invention belongs to the technical field of wireless communication, in particular relating to a signal detection method and a device for a multiple-input-multiple-output wireless communication system. In the invention, the received signal vectors and the estimated channel information are used for detecting and recovering the sent signal vectors. The device of the invention comprises a preprocessing unit, a group of K-Best processing units and a group of zero-forcing processing units, wherein the preprocessing unit carries out real number decomposition and QR decomposition on a channel matrix to form a tree search process; the K-Best processing units extend all child nodes of the reserved father node at the upper layer and calculate the Euclidean distance, and finally, K nodes with theminimum Euclidean distance are reserved and transferred to the next layer; and the zero-forcing processing units extend the child nodes with the minimum Euclidean distance increment in the reserved father node at the upper layer. In addition, a generation technology to be selected, a candidate value sharing structure, a shifting technology, and the like, are adopted. The invention reduces the computation complexity of the MIMO signal detection and increases the speed of the MIMO signal detection.

The invention relates to a zero-force control method and system for a robot. The zero-force control method comprises the following steps: S1, a robot kinetic model is built on the basis of inertia force, centrifugal force, coriolis force, viscous friction force, static friction force and gravity; S2, external force moments of all the joints of the robot are calculated on the basis of the robot kinetic model and feedback data; S3, a speed command is calculated according to the external force moments calculated in the step 2; and S4, a position command is calculated according to the speed command and position feedback. Through the building of the kinetic model, the external force moments of all the joints can be directly calculated, without the assistance of a power-assisted sensor or a torque sensor, so that the cost and the complexity of the system are reduced; by the adoption of a position command control manner instead of a direct torque control manner, the design difficulty in the safety and the stability of the system is reduced; and in addition, since inertia force is considered when the external force moments are calculated, the zero-force control method and system can be suitable for robots with greater dead weight.

The invention provides an industrial robot dragging teaching method without adopting a torque sensor. The method comprises the steps that a joint inverse dynamic model is adopted for joint moment compensation, so that a joint is controlled to be in a near-zero force balanced control state; according to a jitter control principle, feedforward is controlled through drive jitter within a dead zone of friction force, so that the joint is in an activated state, velocity integral grain of a universal control system adopting serial PID control is one order of magnitudes that of a system adopting normal control, and the controller velocity integral gain is increased to improve the dynamic response of the control system in the dead zone of the friction force; a slope dynamic compensation method is adopted for compensating coulomb friction; and a dragging teaching technology is achieved in a universal position control mode, so that switching of a control mode of a driver is avoided. According to the dragging teaching method adopted in the invention, the torque sensor is not needed, and the cost is low.

The invention provides a precoding transmission method for a multi-input and multi-output system, which comprises: a mobile station supposes an emission matrix as a unitary matrix, an MMSE receiver is used for signal combination, an equative channel is calculated, CQI and CDI are obtained and are fed back a base station; according to a channel direction index and channel quality information fed by the mobile station, the base station obtains a zero-forcing precoding emission matrix or a regulated zero-forcing precoding emission matrix corresponding to partial or total possible user combination, carries out multiuser scheduling operation and determines the scheduled user combination; and the base station utilizes the zero-forcing precoding emission matrix or the regulated zero-forcing precoding emission matrix corresponding to the scheduled user combination to carry out precoding and emission; and a scheduled user carries out MMSE receiving. The method reduces error of channel feedback, therefore effectively promoting the utilization ratio of frequency spectrum of the system.

A pressure sensor that is implantable within a living being that wirelessly provides pressure data within the living being to a wireless receiver. The pressure sensor includes an elastic membrane to which at least one capacitive actuator is coupled for applying a known force to the membrane to determine membrane characteristics. The pressure sensor includes a force transducer contacting the membrane for determining the pressure within the living being and which includes an internal calibrating force mechanism. This calibrating force mechanism permits force transducer displacement away from the membrane where a zero force transducer reading is taken and then applying a calibrating force and taking another reading. From these two points, a force transducer characteristic is derived and, along with membrane characteristics, an accurate pressure within the living being is obtained from the sensor. An alternative embodiment replaces the capacitive actuators with a known mass and an external vibratory source.

The utility model discloses a non-cooperative virtual MIMO technology, which belongs to wireless communication field. Reasonable users are chosen to construct co-channel user combination; space-division multiplex of the co-channel users can be realized to increase total system capacity by times without requesting that direction communication ability is arranged between mobile terminals. For an uplink, an uplink co-channel signal can be separated through a minimum quadratic mean deviation algorithm, a zero forcing algorithm, a serial interference elimination algorithm, a maximum likelihood algorithm and other methods. For a downlink, the co-channel interference is obviously restrained for the receiving signal of each user through the downlink signal pretreatment technology; each user can individually receive signal treatment without other user cooperation to greatly simplify the receiver of the users. The non-cooperative virtual MIMO technology can improve total capacity of broadband wireless communication system by times through cooperating with orthogonal frequency division multiplexing technology. The non-cooperative virtual MIMO technology is more particularly suitable for the wireless communication system of division dual.

The invention discloses a space division interference avoiding method for a wireless local area network OBSS (object-based storage system) site. The method comprises the following steps: step 1, a site at the OBSS is enabled to carry beam vector information used by the site through modifying the structure of an RTS (ready to send) frame and a CTS (clear to send) frame, and an MU-MIMO (multi-user multi-input multi-output) sending mode is realized; and step 2, interference AP (access point) in the MU-MIMO sending mode considers the zero-forcing beam direction as an extra constraint condition in the protection time interval of network allocation vector. The space division interference avoiding method for the wireless local area network OBSS site can effectively satisfy the service quality requirement of the site at the OBSS under scarce spectrum resource.

The invention discloses a multi-antenna relay transmission method of decomposing zero-forcing beam-forming based on singular value, which is characterized in that the relay station only makes use of the channel state information from the relay station to the user, and selects the transmission user congregation according to the semi-orthogonal user selection algorithm; the base station and the relay station jointly design the linear pre-processing matrix according to the singular value decomposition of the channel matrix from the base station to the relay station and the zero-forcing beam-forming matrix from the relay station to the user channel matrix; the base station allocates the power by using the power injection algorithm according to the channel state information from the base station to the relay station, and the relay station splits the power in accordance with the sub-flow number of the allocated power from the base station, so as to determine signals for the base station to send and signals for the relay station to transmit; and the transmission method system has advantages of small feedback amount, low complexity, effective control of noise amplification from the relay station, representing asymptotic optimal functions under the conditions that the power of the relay station is very large and that the number of system users are very large, and being suitable to be used in actual systems.

A self-adaptive multiple-input multiple-output (MIMO) transmission/reception system includes a transmitter provided with a serial-to-parallel converter, channel encoders, a plurality of constellation mappers, and transmission power controllers, and a receiver provided with a transmission scheme selection device, a zero forcing/minimum mean square error (ZF/MMSE) detector, reception power controllers, constellation demappers, channel decoders and a parallel-to-serial converter. The transmission scheme selection device generates information regarding plural sets of information to be used, a constellation mapping scheme and transmission power and transmits the generated information to the associated units of the transmitter and receiver, thereby controlling the number of sub code streams, the constellation mapping scheme and the transmission power. The system and method provide superior performance and require minimal feedback information.

The invention discloses a method for estimating a multi-cell joint channel and a device thereof, which can effectively reduce multi-access interference interfering a user or a base station and improve the detection performance of a receiver. The method mainly comprises the following steps: training sequence signals are intercepted from receiving signals; a single cell channel estimation method isused for estimating channels of all cells with same frequency; then iterative operation is used for calculating estimation value of a main path with larger intensity in sequence; the influence of themain path signals are eliminated from the training sequence signal in sequence; and finally, the combination of the main paths is taken as the channel estimation result, wherein, a zero-forcing algorithm is adopted to carry out channel estimation of the main path. In addition, the method also can carry out noise reduction processing to the channel estimation result.

The invention discloses a method for designing multi-user signal and energy simultaneous transmission system low complexity transceivers. The method comprises the following steps that a base station conducts channel estimation to obtain channel vectors between the base station and all users; an interference channel matrix of each user is defined, each interference channel matrix is composed of all channel vectors excerpt the channel vector of the corresponding user, singular value decomposition is conducted on each interference channel matrix to obtain a zero space orthogonal basis matrix, a zero-forcing precode and a maximum joint transmit precode of each user are calculated, and each transmit precode is fixed as the weighted combination of the corresponding zero-forcing precode and the corresponding maximum joint transmit precode; the joint design problem of transmit end precode weights based on transmit power minimizatio, and receiving end power splitting factors is solved through the positive semi-definite relaxation technology to obtain precode weight vectors and the receiving end power splitting factors; finally, the base station conducts precoding on emission signals and sends the power splitting factors to the corresponding users through control channels at the same time. The method reduces the transmit power and also lowers the calculation complexity.

In a socket system and method for coupling a pin of an IC (integrated circuit) device to a contact pad of a circuit board, a zif opening on a socket asserts substantially zero force as the pin of the IC device is inserted therein. In addition, a compression mount lead on the socket presses against the contact pad of the circuit board. Once inside the zif opening, the pin is coupled to the compression mount lead via forking leads that press against the pin. Thus, substantially zero force is applied on the body of the IC device. Furthermore, top portions of the forking leads contact a top portion of the pin toward the IC device to minimize an electrical path length.

The invention provides a multi-input and multi-output (MIMO) transmission method as well as the system thereof. In the method, a transmitting end transmits the information estimated by a signal path, each receiving end generates random beam shaping feedback information and sends out the random beam shaping feedback information to the transmitting end, and the transmitting end carries out user preselection to generate an alternative scheduling user collection, which is sent to each receiving end; each receiving end carries out feedback judgement, if the feedback is allowed, zero forcing beam shaping feedback information is generated, and is sent to the transmitting end; the transmitting end carries out user scheduling to obtain scheduling users, and transmits user data to the scheduling users. The invention has the advantages of the random beam shaping feedback information and the zero forcing beam shaping feedback information at the same time, reduces the feedback spending of the system and the complexity of the implementation, and improves the system capacity.

The invention relates to the technical field of mechanical arm control, and discloses a zero-gravity control method free from moment sensing. The zero-gravity control method comprises the following steps of step 1, obtaining absolute position parameter pulse values of each knuckle of a mechanical arm through an absolute value encoder, and converting the motor pulse capacity to pulse capacity of anorigin of a cartesian coordinate system; step 2, according to the definition of instantaneous velocity and instantaneous acceleration, calculating loop iteration to calculate the instantaneous velocity value and the instantaneous acceleration value; and step 3, performing programming with a software Matlab to determine the algebraic relation expression between the gravity moment of each knuckle arm and the position parameter of each knuckle of the mechanical arm. Through the adoption of the zero-gravity control method disclosed by the invention, for zero force dragging, a moment sensor is notadopted, so that the cost is low and the operability is high, the zero-gravity control method is easy for application and popularization of industrial automation; and besides, the method is mainly realized with the assistance of recognition of the parameters and a software algorithm, so that time and labor are saved, the programming showing and teaching efficiency is high, and later stage maintaining and upgrading are convenient and swift; and the programming efficiency and quality are improved through dragging slowing and teaching planning points, and a foundation is laid for the yield of products.

The invention discloses a channel ambiguity removing method in the MIMO signal blind detection process. The method is characterized by including the first step of dividing a channel matrix of an MIMO system into channels of Mt SIMO systems, the second step of intercepting received signals of each SIMO system, the third step of estimating the channels of each SIMO system through a subspace blind channel estimation algorithm based on second-order statistics according to the intercepted received signals, the fourth step of estimating the obtained channels and the received signals of each SIMO system and balancing out a training sequence of each transmitting antenna through a zero-forcing mode, and the fifth step of utilizing the training sequence obtained through balancing in a first frame and the intercepted signals to carry out channel estimation on subsequent data blocks, enabling the channels of the Mt SIMO systems to form the channel matrix of the MIMO system and obtaining the channel estimation value of the MIMO system. The channel ambiguity removing method has the advantages of being fewer in calculated quantity and low in complexity, eliminating sorting ambiguity, reducing normalization root-mean-square errors and the error rate of the system and improving the reliability of a non-cooperative communication system.

The invention discloses a mechanical arm zero force control experimental system facing direct demonstration. The system comprises a n-degree-of-freedom mechanical arm with n flexible joints, and a main controller; each flexible joint of the mechanical arm is provided with a sensor acquiring circuit and a joint controller; each joint controller communicates with the main controller through a bus mode; each sensor acquiring circuit comprises a joint speed sensor, a joint position sensor and a joint torque sensor for respectively acquiring speed information, position information and torque information of each flexible joint and sending to the main controller; the main controller performs the zero force control to obtain each joint compensation torque value needing compensation and to return to each joint controller; and through a torque-speed loop control algorithm in each joint controller, the received compensation torque values are converted to corresponding joint speeds for joint control.

The invention provides a method for a same base station to make multi-cell system distribute downlink resources. The downlink resources of a service cell are divided into a priority scheduling resource and a residual scheduling resource which are distributed for a user in the service cell. For the priority scheduling resource, a zero forcing wave beam forming technology is adopted; precoding is performed to the user who need to be scheduled in the priority scheduling resource based on PMI and CQI reported by the user according to a proportional fair principle; the scheduling user and the priority scheduling resource distributed for the scheduling user are acquired. For the residual scheduling resource, a collaboration user is determined according to the CQI reported by the user and collaboration information; the zero forcing wave beam forming technology is adopted; the precoding is performed to the collaboration user and the user who are not being scheduled according to the proportional fair principle; the residual scheduling resource is distributed so as to prevent from interference of an adjacent cell. By using the method of the invention, a data volume of downlink channel detection information reported by the user can be reduced and a calculated amount is reduced too.

The invention discloses a method and device for linear pre-coding in a downlink multi-user MIMO (Multiple Input Multiple Output) system. The method comprises the following steps of: obtaining a channel matrix of a downlink channel; carrying out linear operation on the channel matrix by using a zero-forcing principle or a minimum mean-square deviation principle to obtain a pre-coding matrix and a pre-decoding matrix, and repeating the step till convergence to obtain a converged pre-coding matrix; and initializing the speed and maximizing an iterative algorithm by using the converged pre-coding matrix. By using the method disclosed by the invention, the iterative algorithm can obtain speed and larger local optimal solution, thus the speed sum of the communication system is maximized and the speed and the performances of the system can be improved.