Abstract:
PURPOSE: A frequency diversity transmission/reception apparatus and a method thereof capable of transmitting data without reduction by a transceiving antenna are provided to obtain diversity gain of frequency without reducing transfer rate of the data. CONSTITUTION: A data combination unit(200) receives data signals from encoded bitstream. The data combination unit assembles the received data signal. A sub carrier allocation unit(210) allocates the symbol to the subcarrier. The symbols are mapped in subcarrier which is adjacent to the symbols. The diversity properties of the frequency are obtained without transmitting symbols.
Abstract:
A microwave and a millimeter-wave CMOS mixer is provided to reduce a noise generated in a broadband by low maintaining a current inputted to a switching part. A transconductor part(110) amplifies an input signal. The transconductor part obtains transconductance of two times in the same current by using two MOSs(Metal Oxide Semiconductor) of an NMOS and a PMOS at the same time. A switching part(120) outputs a downstream frequency signal by mixing a signal applied to a third node(N3) to a signal applied to a local oscillation input terminal. A capacitor(CD) separates the transconductor part from the switching part by blocking DC component applied between the transconductor part and the switching part. A current source(IB) is provided in order to reduce a noise of the switching part by low maintaining a current applied to the switching part through the third node.
Abstract:
A directional antenna and a transmitter-receiver employing the same are provided to adjust a feeder of signals in order to obtain a desired beam direction. A directional antenna comprises a feeder(32), a radiator and a via. The feeder is symmetrically arranged on a substrate(31). The radiator is arranged on the end part of the feeder. The via connects the feeder to the radiator. The bilateral symmetry degree of the feeder is adjusted in order to control the direction of beam which is radiated through the radiator. A device made of conductive materials is additionally contained in order to reduce grating lobe of the beam while surrounding the feeder, radiator and the via.
Abstract:
A beacon retransmission device using EBS in mobile network, a beacon retransmission method and an initial connection method are provided to share frequency allocation between networks by using EBP and use the frequency allocation efficiently. A beacon frame receiver(210) receives a beacon frame from a management server managing mobile network. The beacon frame comprises the beacon information for the communications in the mobile network and EBS(Echo Beacon Slot) information. The EBS information indicates EBS(Echo Beacon Slot) allocated for the beacon retransmission among the time slots of the super frame. A beacon retransmitter(220) retransmits the Beacon information for EBS.
Abstract:
본 발명은 스위칭 빔 형성 장치에 관한 것으로서, 다수의 지향성을 갖는 다수개의 안테나소자와, 다수개의 안테나소자로부터 수신된 신호를 다수개의 독립적인 빔으로 분리하여 출력시키는 스위칭 빔 형성 회로와; 빔 형성 회로를 통과한 신호 중 원하는 신호가 아닌 나머지 N-1개의 경로의 신호를 연결된 저항으로 연결시키는 다수의 스위치와; 스위칭 빔 형성회로에서 출력된 후 스위치와 저항으로 연결되지 않은 하나의 지향된 신호만을 수신하여 로컬오실레이터에서 출력된 신호와 혼합하는 다수의 주파수 변환기와, 하나의 지향된 신호만을 수신하여 복호화하는 복호부 및 기저대역부로 구성되므로, 신호의 격리도를 충분히 높일 수 있으며, 또한, 증폭기는 임피던스 정합 회로로써만 동작하면 되므로, 임피던스의 값이 최대한 유지되도록 하면서, 전력 소모를 줄일 수 있도록 하여 시스템의 효율 및 신호대잡음비가 개선되고, 신호의 격리도 특성이 향상된 효과가 있다. 스위칭, 빔, 버틀러 메트릭스, 안테나,
Abstract:
A method and an apparatus of generating a signal for an initial ranging in an OFDMA(Orthogonal Frequency Division Multiple Access) system are provided to simply generate plural symbols with continuous phases irrespective of the number of symbol for the initial ranging by using a single mathematical equation. A ranging code generator(308) generates a ranging code. A ranging channel generator(310) modulates the ranging code and generates L symbols by phase-rotating the modulated ranging codes according to a symbol index and a sub-carrier index. The ranging channel generator maps the symbols on a constellation to the sub-carrier according to an index of the sub-carrier. A converter converts the mapped symbols into a time domain and generates sample data of the ranging symbol. A guard interval insertion unit(304) copies a tail portion of the sample data corresponding to the size of the guard interval, and inserts the copied portion in front of the sample data as the guard interval, such that the initial ranging signal is formed.
Abstract:
본 발명은 유전체 도파관 대 전송선의 밀리미터파 천이 장치에 관한 것으로, 유전체 도파관과 전송선과 슬롯을 이용한 밀리미터파 천이 구조를 구현하여 저손실로 신호를 천이시킬 수 있는, 유전체 도파관 대 전송선의 밀리미터파 천이 장치를 제공하고자 한다. 이를 위하여, 본 발명은 밀리미터파 천이 장치에 있어서, 최상위 유전체기판 상부에 신호 천이 방향을 따라 입력단과 출력단에 각각 배치되어 신호를 천이시키기 위한 전송선; 최하위 유전체기판의 상하부 접지면과 상기 신호 천이 방향을 따라 배치된 비아열에 의해 형성되어 신호 천이 경로가 되는 유전체 도파관; 및 각 유전체기판의 상부 접지면의 신호 천이 경로 상에 각각 배치되며, 상기 전송선 및 상기 유전체 도파관을 결합시켜, 입력단 전송선으로부터 입력된 신호를 상기 유전체 도파관을 경유하여 출력단 전송선으로 천이시키기 위한 슬롯을 포함한다. 밀리미터파, 천이 구조, 유전체 도파관, 전송선, 슬롯, 매칭패드, 중간 비아, 비아벽
Abstract:
A method of generating a pilot pattern for adaptive channel estimation, a method of transmitting and receiving using the pilot pattern and an apparatus thereof are provided to minimize channel estimation performance degradation due to interpolation under severe channel environment as maintaining low pilot density. According to a method of generating a pilot pattern for adaptive channel estimation, the size of a slot where the pilot pattern is repeated in a time domain and a frequency domain is determined(S301). A random subcarrier in a first OFDMA(Orthogonal Frequency Division Multiple Access) symbol in the time domain slot is determined as a pilot insertion position(S303). Frequency-time distance from pilots of all prior OFDMA symbols in the time domain slot to each remaining sub carrier is calculated, as to each remaining sub carrier of the present OFDMA symbol after the first OFDMA symbol in the time domain slot(S304). Minimum distance in each frequency-time distance assembly of the remaining subcarriers is compared. A subcarrier where the frequency-time minimum distance has a maximum value is determined as pilot insertion position(S312).
Abstract:
An apparatus and a method for generating jacket LDPC(Low Density Parity Check) codes of a Richardson type are provided to constitute an encoder with simple hardware by reducing the complexity of calculating the LDPC codes. An apparatus for generating jacket LDPC codes of a Richardson type includes a jacket pattern generating unit(400), an encoding-rate/encoding-length control unit(410), a zero padding/canceling unit(430), a CPM(Circulant Permutation Matrix) inserting unit(420), and an H matrix generating unit(440). The jacket pattern generating unit(400) generates a jacket matrix based on a jacket pattern in which an inverse matrix of a square matrix is represented as the inverse of each element. The encoding-rate/encoding-length control unit(410) outputs a prime number, which determines the size of CPM based on the size of the jacket matrix generated in the jacket pattern generating unit(400), to satisfy a requested encoding rate. The zero padding/canceling unit(430) inserts zero into the jacket matrix generated in the jacket pattern matrix, and generates a non-square matrix. The CPM inserting unit(420) generates a first CPM of a unit matrix which only has diagonal factors based on the prime number outputted in the encoding-rate/encoding-length control unit(410), and generates all second CPMs by shifting the first CPM corresponding to each factor of the jacket matrix. The H matrix generating unit(440) generates an H matrix of a Richardson type based on the non-square jacket matrix and the second CPM.
Abstract:
Provided is a method of assigning a frequency channel using efficient spectrum sensing in a multiple Frequency Assignment (FA) system. The method includes a channel sensing process, wherein a base station (BS) of a secondary user classifies multiple frequency channels licensed to a primary user into a plurality of channel state sets according to usage states, periodically senses channel states by changing a sensing period according to the types of classified channel state sets, and manages the sensed channel states as frequency channel state set information; a channel state set broadcasting process, wherein the BS transmits the frequency channel state set information manage d in the channel sensing process to secondary user terminals using a broadcast message; and a channel assigning process, wherein if the BS receives a channel assignment request message from a new secondary user terminal which has received the broadcast message, the BS assigns an unused frequency channel from among frequency channels licensed to the primary user to the new secondary user terminal using the frequency channel state set information. Accordingly, a frequency channel can be assigned to a secondary user requesting channel assignment using frequency channel state set information without a primary user experiencing interference noise.