Abstract:
PURPOSE: A continuous orthogonal band diffusion code hopping multiplexing method at a non-interference wireless communication CDMA system is provided to increase dramatically the number of downlink channels of CDMA non-interference wireless mobile communications system based on a continuous orthogonal band diffusion code having a small family size. CONSTITUTION: A transmitter (210) transmits a signal to a receiver (230) through a multipath (220). A free-rake transmitter connected to a ZCD (Zero Correlation Duration) code comprises a spreader (211), a ZCD code generator (212), a code hopping multiplexer (213), and a free-rake coupler (214). A receiver outputs an input signal passing a multipath channel through a matched filter (231) and a decision unit (232) after adding a noise signal to an input signal. [Reference numerals] (210) Transmitter (BS); (211) Spreader; (212) ZCD code generator; (213) Code hopping multiplexer; (214) Free-rake coupler; (220,AA) Multipath channel; (230) Receiver (MS); (231) Matched filter; (232) Decision unit; (BB) Noise n (t); (CC) Single path receiver
Abstract:
PURPOSE: An ultra wideband communication modem is provided to control a direction of a directional antenna. CONSTITUTION: An RF processing unit(140) drops a frequency of the received ultra wideband signal. The RF processing unit transmits the ultra wideband signal which frequency is descended to a parallel-to-serial converter. The RF processing unit increases a frequency of a serial signal received from the parallel-to-serial converter. The RF processing unit transmits a serial signal which frequency is increased to a directional beam antenna(150). The directional beam antenna transceives a wireless signal by forming the directional beam. The directional beam antenna has a structure which can control the direction of the directional beam.
Abstract:
본 발명은 다차원 도약 패턴 충돌시 충돌 구간에서의 송신 제어 방법 및 장치에 관한 것이다. 본 발명에서는 주어진 직교 무선 자원을 송신측 및 수신측 사이의 통신 규약에 의하여 다차원 직교 자원 영역에서 도약 선택하며, 해당 채널은 다차원 도약 패턴에 의하여 구별된다. 이때, 제2 통신국별로 특정한 다차원 도약 패턴을 할당하고, 다차원 도약 패턴은 제2 통신국에 영구적으로 할당될 수도 있고, 호설정시에 제1 통신국으로부터 할당받을 수도 있다. 또한, 다차원 직교 자원 도약 패턴이 각 제2 통신국에게 영구적으로 할당되는 것은 제2 통신국의 ESN(Electronic Serial Number) 등과 같이 유일한 식별자를 바탕으로 다차원 도약 패턴이 정해질 때이다. 이런 경우, 제2 통신국의 다차원 도약 패턴이 서로 독립이기 때문에 특정 순간에 동일한 직교 자원 좌표가 서로 다른 제2 통신국에 동시에 할당될 수 있다. 본 발명에 따르면, 다차원 직교 자원 도약 다중화 방식을 채택한 시스템의 성능을 향상시키기 위하여 전송과 천공의 2분법적으로 이루어지는 다차원 직교 자원 도약 패턴 충돌시 처리 방법을 세분화함으로써 천공의 경우를 줄일 수 있다. 직교 자원, 도약 패턴, 다차원, 충돌, 다중화
Abstract:
The present invention utilizes a calibration signal weight vector as a response vector corresponding to a predetermined orientation angle of the antenna, thereby reducing an interference signal and enhancing a data communication effectively. The calibration method of an array antenna begins with generating a calibration signal in order to measure a transfer function of an array receiving means. A calibration signal vector is injected into the array receiver/transmitter, after multiplying a divided calibration signal and a predetermined weight vector corresponding to each channel together. The divided calibration signal is obtained by dividing the calibration signal by total number of channels. A calibration coefficient is obtained by using that the transfer function of each channel is estimated by analyzing the signal injected from the array receiver or transmitter. Finally, an interference signal is eliminated, by multiplying the received signal of a baseband and the calibration coefficient together.
Abstract:
PURPOSE: An adaptive code bank managing method for allocating code channels in a mobile communication system and an apparatus therefor are provided to calculate the maximum number of allocable code channels according to wireless channel environments, and to adaptively vary the code bank by the size of communication traffic, so as to improve efficiency in communication channel use. CONSTITUTION: If a request for using code channels is generated, a channel number adjustor of a code bank management unit calculates the number of necessary code channels(S100,S110). The channel number adjustor calculates a link gain between a mobile station and a base station, on the basis of power amount allocated to all currently used code channels, total noise and interference amount, and SIR(Signal-to-Interference Rate)(S120,S130). The channel number adjustor calculates the number of additionally allocable code channels(S140). The channel number adjustor calculates the size of a code bank(S150). A channel allocator compares the number of necessary codes with the number of available channel codes(S160). If the number of necessary codes is larger, the channel allocator declares the failure of code channel allocation(S170). And if the number of necessary codes is smaller, the channel allocator allocates code channels(S180).
Abstract:
Disclosed are an apparatus for forward beamforming using a terminal feedback and a method thereof. The base station estimates an angle of arrival (AOA) range of a user signal from reverse link received data and calculates a plurality of beamforming weights steering the estimated AOA range. Then, the base station transmits a user pilot signal by sequentially using the plurality of beamforming weights at different time areas through a control channel to estimate a forward channel conditions. A terminal calculates the user pilot signal power for all fingers at the respective time areas and feeds a time area number corresponding to the greatest power back to the base station. The base station transmits a data channel signal using a beamforming weight corresponding to the time area number fed back from the terminal.
Abstract:
PURPOSE: A sequential decoding apparatus of a mobile communication system and a method thereof are provided to efficiently decode a stream of symbols encoded by a convolution code when the stream is transmitted through a channel in the mobile communication system. CONSTITUTION: A CPU(202) controls a total decoding operation. An optimal path determination buffer(210) sequentially stores an optical path. A competitive path determination buffer(210) sequentially stores at least one competitive path. A buffer controller controls the optimal path determination buffer(210) and the competitive path determination buffer(210) using a control signal from the CPU(202). An encoder(214) encodes signals from the optimal path determination buffer(210) and the competitive path determination buffer(210) by the set bit number. A bit metric calculation(216) calculates a metric using the signals from the optimal path determination buffer(210) and the competitive path determination buffer(210) and an input signal.
Abstract:
PURPOSE: A multiuser interference cancellation receiver for a TDD-CDMA(Time Division Duplex-Code Division Multiple Access) system and a method for controlling the interference cancellation are provided to perform interference cancellation for signals having high power values even when differences of signal power values are wide among users, so as to minimize errors in the detection of user signals having low signal power values. CONSTITUTION: A data extractor(100) extracts data from received signals and outputs the extracted data. A signal delay part(200) delays the signals outputted from the data extractor(100) during a predetermined time, and outputs the delayed signals. An interference cancellation selection part(300) extracts midamble signal channels from received original signals, to select and output users of the subject of the first interference cancellation. The first step interference cancellation block(400) receives data of the received signals from the data extractor(100), to perform the first parallel interference cancellation for the selected users of the first interference cancellation subject and output reproduction signals. And the second step interference cancellation block(500) receives data of the received signals delayed during the predetermined time and outputted from the signal delay part(200), to perform the second parallel interference cancellation using the first reproduction signals outputted from the first step interference cancellation block(400).
Abstract:
This invention relates to a method and apparatus for increasing the performance of searcher by using the array antenna when the signal to interference plus noise ratio is low. The two-dimensional searcher performs the spatial-filtering to reduce the noise and interference components and then correlates the spatial-filtered signal with a pseudo noise (PN) code to thereby detect the incoming signals and acquire the corresponding code timings. Furthermore, the two-dimensional searcher can be used to increase the performance of a finger beamformer in two ways. One is to use searcher beamforming weight as initial finger beamforming weight to increase the convergence speed in the adaptive beamforming algorithms. The other is to reduce an amount of computation in the angle of arrival estimation algorithms by calculating the azimuth power spectrum only for the specific angle range.