Samsung Electronics Co., Ltd.

Amotron Co., Ltd.

Yuyu Co., Ltd.

Joon Suk Kim

Wook Bong Lee

Sung Soo Kim

Eun Sung Jeon

Min Ki Ahn

ByungKyu Kim

Byung Kyu Kim

Jin-Hong Kim

Donghoon Kim

Jae-woo Kim

Boris Bazarov

Provided is method for generating a precoder in a Multi User Multiple Input and Multiple Output (MU MIMO) communication system. The method involves receiving channel information and quality information of a channel from a plurality of stations. It is determined whether a first condition is satisfied on the basis of the received information, if so, a type of matrix inversion is selected from among a plurality of matrix inversion types for precoding. It is determined whether a second condition is satisfied on the basis of the provided information, and a type of decomposition from a plurality of decomposition types for precoding is selected if the second condition is satisfied. A precoder is generated on the basis of the selected result.

Method for generating precoder in multi user multiple input and multiple output communication system

A beam transmitting device improves performance of a communication channel. The beam transmitting device includes a controller configured to transmit a null data packet (NDP) and receive channel information; and a smoothing circuit configured to smooth a plurality of beamforming vectors in the channel information. The smoothing circuit includes a weight calculator configured to calculate a common phase factor using two adjacent beamforming vectors among the plurality of beamforming vectors, and a moving average filter configured to perform the smoothing using the common phase factor.

Beam transmitting device and operating method of the same

Provided is method for generating precoder in a Multi User Multiple Input and Multiple Output (MU MIMO) communication system. The method involves receiving channel information and quality information of a channel from a plurality of stations. It is determined whether a first condition is satisfied on the basis of the received information, if so, a type of matrix inversion is selected from among a plurality of matrix inversion types for precoding. It is determined whether a second condition is satisfied on the basis of the provided information, and a type of decomposition from a plurality of decomposition types for precoding is selected if the second condition is satisfied. A precoder is generated on the basis of the selected result.

A method for wireless communications includes: receiving a sounding packet from an access point; determining a rank of a channel matrix corresponding to a communications channel; and when the rank of the channel matrix is a full rank: selecting at least one of a plurality of pieces of codebook information previously stored in a memory, as beamforming information, transmitting the beamforming information to the access point, and applying channel smoothing to a communications channel provided by the access point.

Method and apparatus for wireless communications

A vacuum generating apparatus for a vacuum cleaner is provided, in which an axial type coreless brushless direct-current (DC) motor is implemented in the form of a rotor-impeller integration structure. The vacuum generating apparatus includes an axial type brushless DC motor in which disc-shaped upper and lower rotors are symmetrically disposed facing the upper and lower portions of a disc-shaped stator at either end of a rotating shaft rotatably supported in the inner circumferential portion of the stator, upper and lower impellers integrally fixed in the upper and lower rotors, respectively, and upper and lower housings whose outer circumferential portions are combined with the outer circumferential portions of the respective disc-shaped stator such that air sucked via sucking inlets formed at the center of the housings is guided to a discharging outlet together with the stator. A single rotor structure can also be adopted.

Vacuum generating apparatus with multiple rotors

A stator assembly operated in a 2-phase drive manner including first and second stator coils wound in a star shape with a plurality of projections and a plurality of grooves, and arranged with a predetermined phase difference; and an annular supporting body into which the first and second stator coils are inserted for supporting the coils, insulating them from each other. Each stator coil includes four projections and four grooves, and there is a phase difference .theta. between the first and second stator coils, the difference determined by the following equation: .theta.=360/2P.+-.360/P, wherein P denotes the number of a rotor's magnetic poles. A brushless direct-current motor operated in a 2-phase drive manner includes a stator having first and second stator coils wound in a star shape with a plurality of projections and a plurality of grooves, and arranged with a predetermined phase difference; a shaft rotatably supported on a case; at least one disk-shaped multi-pole rotor supported by the shaft with an air gap from the stator in an axial direction; first and second location sensors provided to the stator with the same phase difference as that of the first and second stator coils for detecting the rotor's magnetic pole; and a driving control circuit driving the first and second stator coils in response to the detection of the magnetic pole of the rotor by the first and second location sensors, wherein said phase difference is determined by the equation: .theta.=360/2P.+-.360/P (P=the number of a rotor's magnetic poles).

Built-in stator of star-winding mechanism and method of producing the

A two-phase brushless direct-current (BLDC) motor having a single Hall effect device. The BLDC motor includes a stator comprised of 2n coils grouping as first and second phase coils at a uniform interval, and a rotor which N-pole and S-pole magnets of the same number as that of the stator coils are alternately disposed, the 2n magnets forming n pairs, each pair of magnets are disposed at a uniform interval, wherein a distant ratio from the center of one N-pole magnet to the centers of the S-pole magnets adjacent the N-pole magnet is established into 1:1.4. Since 2n auxiliary magnets are disposed annularly on the rotor with the same length as each other corresponding to the N-pole and S-pole magnets, a single Hall effect device detects the magnetic pole by magnetic flux of the rotating auxiliary magnets and generates the rotating position signal of the rotor, so that a switching controller can activate the first and second phase coils alternately. Thus, the motor has a simple driving circuit, a high efficiency and a small torque ripple.

Two-phase brushless direct-current motor having single hall effect device

A double rotor-type brushless direct-current motor includes first and second annular-shaped rotors each having a plurality of north and south-polar magnets which are alternately disposed at a predetermined distance; a rotating shaft connected to a central portion of the rotors thorough a bushing; upper and lower cases receiving and rotatably supporting opposite ends of the rotating shaft; an annular-shaped stator having a plurality of stator coils supported by a molding filler to apply electromagnetic force to the first and second rotors in an opposite direction to each other, the stator being mounted between the first and second rotors at a predetermined clearance; and a control printed circuit board for applying a driving current with respect to the stator, the control printed circuit board being mounted one of the upper and lower cases; wherein the upper and lower cases, the control printed circuit board, the first and second rotors have a plurality of ventilating holes for circulating air from the outer side of the motor to the inside of the motor.

Coreless-type BLDC motor and method of producing stator assembly having

An interconnecting method for a semiconductor device is disclosed in which a conductive layer containing aluminum is formed on a lower structure formed on a substrate. An insulating layer is formed on the conductive layer. A photoresist pattern for defining a portion where an opening is to be made is formed on the insulating layer. Then, the insulating layer is isotropically etched by wet etching with the photoresist pattern as an etching mask. The insulating layer remaining after the isotropical etching is taper-etched by RIE to form the opening. To ensure that the conductive layer is exposed by the opening, the resultant structure is overetched by using a mixed gas of fluorocarbon-containing gas and oxygen. This resultant structure is RIE-sputtered using fluorocarbon-containing gas such that polymer or nonvolatile by-products generated when the opening such as a via hole is formed, are completely removed.

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Seoul, South Korea

Joon Suk Kim