Samsung Electronics Co., Ltd.

Telecis Technologies,inc.

Samsung Thomson-csf Co., Ltd.

Telecis Wireless, Inc.

Je-Woo Kim

Jong-Hyeon Park

Soon-Young Yoon

Jae-min Ahn

Jae-Min Ahn

Bok-Tae Shim

Kyung-Sup Han

Hee-Won Kang

Young-Ky Kim

Jong-Seon No

Ha-Bong Chung

Hong-Yeop Song

Si-Hyun Bae

Igor E Timofeev

Chang-soo Park

Ki-Soo Kim

Jae-Heung Yeom

Hyung-Suk Kim

Chang-Soo Park

Byeong-Ho Lee

Young-Jun Hwang

Kyung-sup Han

Hyung-Weon Cho

Kyu-Hak Kim

Sang-Hoon Roh

Tae-Ryun Chang

Jung-Hyo Woo

Hajime Gikuchi

In-Sik Cho

In-Seen Baek

An orthogonal frequency division multiplexing (OFDM) communication system and method for improving frequency utilization efficiency. In the system, a Reed-Solomon encoder codes input information data, and outputs a Reed-Solomon block having a second number of Reed-Solomon symbols each having a first number of Reed-Solomon symbol elements. An interleaver receives the Reed-Solomon block, and disperses the Reed-Solomon symbol elements existing in a specified one Reed-Solomon symbol within the received Reed-Solomon block in the same sub-channel positions in a fourth number of sub-channels of each of a third number of consecutive OFDM symbols.

Orthogonal frequency division multiplexing/modulation communication system for improving ability of data transmission and method thereof

An Orthogonal Frequency Division Multiplexing (OFDM) communiation system and method for improving frequency utilization efficiency. In the system, a Reed-Solomon encoder codes input information data, and ouputs a Reed-Solomon block having a second number of Reed-Solomon symbols, each Reed-Solomon symbol having a first number of Reed-Solomon symbol elements. An interleaver receives the Reed-Solomon block, and disperses the Reed-Solomon symbol elements existing in a specified one Reed-Solomon symbol within the received Reed-Solomon block in the same sub-channel position in a fourth number of sub-channels of each of a third number of consecutive OFDM symbols.

Data transmitter and receiver of a spread spectrum communication system using a pilot channel

There is provided a channel estimating apparatus and method in a radio communication system. In the channel estimating apparatus, a fading estimator estimates a channel using preset symbols of an input signal, a first interpolator interpolates the other symbols of the input signal based on the fading estimation, a first inverter inverts the output signal of the first interpolator, a first delay delays the input signal for a predetermined time, a first multiplier primarily compensates the output signal of the first delay by means of the output signal of the first inverter, a second interpolator interpolates each symbol of the input signal relating to primarily compensated symbols in a predetermined period before and after the symbol, a level controller controls the level of the output signal of the second interpolator, a second inverter inverts the output signal of the level controller, a second delay for delays the primarily compensated signal for a predetermined time, and a second multiplier secondarily compensates the output signal of the second delay by means of the output signal of the second inverter.

Apparatus and method for channel estimation in radio communication system

A frequency hopping (FH) communication device and a frequency hopping method are provided. The frequency hopping communication device includes a first frequency hopping unit for receiving data to be transmitted, orthogonal frequency division multiplexing (OFDM) modulating the received data using the frequency of a subcarrier corresponding to a first frequency hopping code among the frequencies of a predetermined number of subcarriers, and outputting first frequency hopped data on which the data to be transmitted is loaded and a second frequency hopping unit for second frequency hopping the first frequency hopped data by mixing the first frequency hopped data with a carrier composed according to a second frequency hopping code. When jamming occurs, the frequency affected by jamming is restricted to a narrow bandwidth. Therefore, it is possible to reduce the influence of jamming and to easily restore data even though jamming occurs. Also, it is possible to improve the degree of concealment of data.

Frequency hopping communication device and frequency hopping method

There are provided adaptive beamforming algorithms for an adaptive array smart antenna. According to one embodiment of the present invention, the adaptive array smart antenna constructs an input signal matrix with a predetermined number of input signals, computes a transmission signal matrix that minimizes a cost function using a first steering matrix set to an initial value and the input signal matrix, computes a second steering matrix that minimizes the cost function using the transmission signal matrix and the input signal matrix, maps the second steering matrix on a unit circle, constructs a third steering matrix with the mapped values, normalizes the third steering matrix and determining whether the third steering matrix converges, and demodulates data using the transmission signal matrix if the third steering matrix converges.

Method for processing signal of adaptive array smart antenna in array smart antenna system

A data transmitter and receiver in a DS-CDMA communication system designed to prevent a serious amplitude shift in a transmission signal, facilitate recovery of data and clock signals and relieve the constraint of using a high linearity, high performance amplifier. The data transmitter includes a spread signal generating device, in which I-arm and Q-arm information signals of the first channel are spread by I-arm and Q-arm PN codes, respectively, and I-arm and Q-arm information signals of a predetermined number of following channels are spread by an inverted Q-arm PN code and the I-arm PN code, respectively. The data receiver includes a despread signal generating device, in which an I-arm despread signal is generated by multiplying I-arm and Q-arm digital baseband spread signals by I-arm and Q-arm PN codes, respectively, and adding the multiplication results, while a Q-arm despread signal is generated by multiplying Q-arm and I-arm digital baseband spread signal by an inverted I-arm PN code and the Q-arm PN code, respectively, and adding the multiplication results.

Data transmitter and receiver of a DS-CDMA communication system

A spreading code generating device for a Code Division Multiple Access (CDMA) communication system. The device comprises a PN (Pseudorandom Noise) code sequence generator for generating PN and PN sequences; an orthogonal code generator for generating first and second orthogonal codes which perform Differential Phase Shift Keying (DPSK) state transitions at intervals of at least two chips; and a spreading code generator for generating spreading codes C and C by mixing the PN and PN code sequences with the first and second orthogonal codes such that a present phase of the spreading codes C alternately makes Quadrature Phase Shift Keying (QPSK) and DPSK state transitions with respect to a previous phase of the spreading codes C and C .

Device and method for generating spreading code and spreading channel signals using spreading code in a CDMA communication system

A device and method are provided for reducing the peak-to-average power ratio of a mobile station's transmit power in a mobile communication system by spreading and modulating the transmission data by a complex spreading sequence. The complex spreading sequence is generated to have a plurality of chips and a phase difference of 90&deg; between every two successive complex chips in response to each chip of a PN (Pseudo Noise) sequence. The device and method flexibly control the mobile transmit power by limiting its peak-to-average power ratio to a specific range and thus confining the mobile transmit power to a linear characteristic portion in a characteristic curve of a power amplifier. The phase of the complex spreading sequence is prevented from shifting by 180&deg; (i.e., &pgr;) to maintain the mobile transmit power in the linear portion of the power amplifier characteristic curve.

Device and method for reducing the peak-to-average power ratio of a mobile station's transmit power

A small and lightweight base station transceiver utilizes a plurality of low-powered time division duplexing switches instead of a single high-powered time division duplexing switch. The base station transceiver includes a forward signal path, a reverse signal path, and a plurality of time division duplexing switches being switchable to the forward signal path or the reverse signal path according to a time division duplexing timing control signal generated from a time division duplexing timing controller. The plurality of time division duplexing switches corresponds to N time division duplexing switches where the symbol N represents a number. Output signals of the time division duplexing switches are filtered in a plurality of N bandpass filters, coupled in a junction coupler, and then radiated in the air through first and second antennas. The junction coupler couples the outputs of odd-numbered bandpass filters to transfer the coupled signals to the first antenna, and couples the outputs of even-numbered bandpass filters to transfer the coupled signal to the second antenna, so as to reduce mutual interference among the channels.

Base station transceiver for frequency hopping code division multiple access system

A spread spectrum apparatus for a code division multiple access communication system maintains orthogonality between transmission signals. In the spread spectrum apparatus, a spreader combines first and second input signals with corresponding pseudo noise sequences to generate first and second spread signals. A zero-crossing detector determines whether zero-crossing occurs between the first spread signal and the second spread signal to generate a zero-crossing detection signal. A first delay staggers the first spread signal in a first direction and a second delay staggers the second spread signal in a second direction. A first selector selects one of the first spread signal and a first staggered signal and a second selector selects one of the second spread signal and a second staggered signal in response to the zero-crossing detection signal. Accordingly, first and second staggered signals are selected when zero-crossing occurs, and first and second spread signals are selected when zero-crossing does not occur, thereby maintaining orthogonality of transmission signals.

Modulation apparatus and method using zero-crossing detection

There are provided spread spectrum signal generating devices and methods in a transmitter of a mobile communications system using a plurality of logical channels. In the spread spectrum signal generating devices, a multiplexer time multiplexes a pilot channel signal and a control channel signal which are output at substantially constant power levels. A first orthogonal encoder orthogonally spreads the output of the multiplexer with an orthogonal code. A second orthogonal encoder orthogonally spreads voice channel data of a variable bit rate with an orthogonal code. A third orthogonal encoder orthogonally spreads packet channel data of a variable bit rate with an orthogonal code. An IQ signal mapper adds the outputs of the first and third orthogonal encoders, outputs the added signal as a first channel signal, and outputs the output of the second orthogonal encoder as a second channel signal. A PN spreader spreads the first and second channel signals with PN codes and outputs a final spectrum spread signal, which exhibits a substantially minimized peak-to-average power ratio.

Spread spectrum signal generating device and method in transmitter of mobile communications system

A device and method for generating a pseudo-orthogonal code for use in orthogonally spreading channel data in a CDMA mobile communications system. M orthogonal codes are selected from N orthogonal codes, for forming a pseudo-orthogonal codes, and the elements of the selected M orthogonal codes are sequentially interlaced to generate the pseudo-orthogonal code as a sequence of M&times;N elements.

Device and method for generating spread spectrum signal using pseudo-orthogonal code in CDMA mobile communications system

A circuit and process for generating spread signals using orthogonal codes in a DS-CDMA mobile communication system. The process and circuit contemplate the use of a zero-crossing detector for detecting an I-channel signal and a Q-channel signal to generate a zero-crossing detection signal, a delay for phase-delaying the Q-channel signal by 90&deg;, and a multiplexer for outputting one of the Q-channel signal and the phase-delayed signal according to the zero-crossing detection signal. The multiplexer outputs the Q-channel signal to maintain an orthogonality between the I-channel signal and the Q-channel signal, when the zero-crossing is not detected. When the zero-crossing is detected however, the multiplexer phase-delays the Q-channel signal by 90&deg; and outputs the phase-delayed Q-channel signal to maintain a &frac12; chip offset. Therefore, the device can minimize phase errors, maintaining an orthogonality between the I-channel signal and the Q-channel signal.

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Kyonggi-do, South Korea

Je-Woo Kim