International Business Machines Corporation

Industrial Technology Research Institute

National Yang Ming Chiao Tung University

National Science Council

General Electric Company

Chung Shan Institute of Science and Technology

Chia-Chi Huang

David Frederick Bantz

Kadathur S Natarajan

Yung-Liang Huang

Frederic J Bauchot

Chorng-Ren Sheu

Yuh-Maiw Jong

Frederick J Bauchot

Robert Thomas Cato

Pang-An Ting

Meng-Chun Chang

Charles M Puckette

Anand Narasimhan

Tien-Shou Shieh

Fabien P Lanne

Ilan Kessler

Jiun-Yo Lai

Yu-Jung Chang

Shin-Yuan Wang

Michelle M Wetterwald

Chun-Chian Lu

Yu-Hwai Tseng

Chun-Ying Ma

Chao-Wang Huang

Michele M Wetterwald

Pai-Hsiang Shen

Jian-Hui Shen

Shin-Iuan Wang

Nicholas J Moulton

Kon-Da Fan

Shyh-Jye Jou

Kang-Lun Chiu

Ping-Ju Lin

Nicholas John Moulton

A method of synchronization of wireless communication system is provided. The method includes the following steps: receiving a symbol from a wireless communication system by a user equipment; detecting ISI-free region of the received symbol; setting an endpoint of a FFT window within the ISI-free region; detecting shifted primary control frequency and shifted secondary control frequency of the symbol; calculating ICFO based on the shifted primary control frequency and a primary control frequency; calculating secondary control frequency based on ICFO and shifted secondary control frequency; finding the preamble of a frame based on the secondary control frequency; and determining, based on the preamble, a start point of the frame.

Method and architecture of synchronization of wireless communication system

The disclosure provides a multilayer composition containing fluoropolymer and method for fabricating the same, and a solar cell module. The multilayer composition includes: a fluoropolymer layer; a non-fluorinated polymer layer; and an adhesion promoter layer formed between the fluoropolymer layer and the non-fluorinated polymer layer, wherein the adhesion promoter layer includes aromatic diamines or aromatic polyamines.

Multilayer composition containing fluoropolymer and method for fabricating the same, and solar cell module

A progressive parallel interference canceller (PPIC) and a method and a receiver thereof are illustrated. The PPIC reconstructs each subchannel interference reconstruction signal through several iterations and subtracts the corresponding subchannel interference reconstruction signal from each subchannel frequency-domain reception signal to obtain a subchannel frequency-domain signal. Thereby, according to the present disclosure, inter-channel interference can be cancelled without re-performing channel coding or estimating the signal to noise ratio (SNR) or frequency offset.

Progressive parallel interference canceller and method and receiver thereof

A system and method of transmit diversity for wireless communication. The system includes a transmitting terminal having a plurality of transmission antennas and a receiving terminal having a plurality of receiving antennas. The method includes analyzing channel state information obtained by the transmitting terminal; selecting an antenna to be one in use from the receiving antennas; matching the selected antenna in use with the wireless signals that are to be transmitted; transmitting wireless signals that are matched to the receiving terminal for being calculated and determining the pre-selected antenna in use, thereby significantly reducing complexities of the receiving terminal.

System and method of transmit diversity for wireless communications

A method and apparatus for the signal synchronization of an orthogonal frequency division multiplexing system includes a delay conjugate multiplication module, a phase processor and an edge detector. It provides estimates for the boundaries of inter-symbol interference free region by utilizing the characteristics of a guard interval in combination with the techniques of the delay conjugate multiplication module, phase differential operation, symbol-by-symbol average operation, and edge detection. The method determines a fixed optimal threshold for directly separating the inter-symbol interference region in a mobile environment to obtain an inter-symbol interference free version of symbol information.

Method and apparatus for synchronization of the OFDM systems

A vector network analyzer using sliding correlator techniques and multi-user detection techniques. The sliding correlator technique is based on the time domain sliding effect caused by a small clock frequency offset in the pseudo random code generators of a transmitter and a receiver. A time scaled version of the impulse response of the device under test can be obtained from the time domain slided pseudo random code signals by using a correlator. A multi-user detection method is introduced using two uncorrelated pseudo random codes. One of the uncorrelated pseudo random codes measures the D.U.T. and another code is a reference channel. These codes can be demodulated and despread with one receiver module. A Fast Fourier Transform of the measured impulse response is the frequency response of the measured signal. By using multi-user techniques and calculating the frequency domain despreaded test signal and the frequency domain despreaded reference signal repeatedly, the test device frequency responses is obtained and disturbances of resulting signals caused by the receiver chaining characteristics and multi-user PN code effects are eliminated. The measurement time is also reduced as a single measurement generates output data for a wide frequency band instead of for a single frequency.

Vector network analyzer architecture based on sliding correlator techniques

A method and an architecture for correcting carrier frequency offset and spreading code timing offset in a direct sequence spread spectrum communication system are disclosed. In the present invention, the carrier frequency offset is divided into an integer part and a fractional part, wherein the integer part is defined as integer multiples of the reciprocal of the period of a spreading code. The integer part of the carrier frequency offset can be obtained by matching received signals with a spreading code whose central frequency is located at integer multiples of the reciprocal of the period of the spreading code and searching the one, of the matched results, with the largest amplitude. Besides, a direction flag can be obtained by comparing the amplitude of the searched one with that of the matched results neighboring the searched one. After correcting the integer part carrier frequency offset, the difference between the phase angles of two successive matched results can be calculated and used to calculate the fractional part of the carrier frequency offset according to the direction sag. After the carrier frequency offset is corrected, the correction of the timing offset of the spreading code can be made by searching for the first path of the channel impulse response which produces the minimum delay spread.

Method and architecture for correcting carrier frequency offset and spreading code timing offset in a direct sequence spread spectrum communication system

The present invention provides a CDMA RAKE receiver that computes a data detection using Fast Fourier Transform (FFT) matched filters. Signals received are processed in frequency domain by the RAKE receiver. The RAKE receiver includes a pilot signal spreading code matched filter, a data signal spreading code matched filter and a channel matched filter. The pilot signal spreading code matched filter removes a spreading code of the pilot signal. The data signal spreading code matched filter removes a multiple access spreading code of the data signal. A channel matched filter estimates the channel frequency response and combine the received data signal from different paths before a decision is made. For increasing the CDMA system capacity, the RAKE receiver uses a interference cancellation method. A downlink receiver at a mobile station estimates the interference of a pilot signal and subtracts the pilot interference from the received signal before data detection. The uplink receivers at a base station use a multi-stage parallel interference cancellation process for removing multiple access interference from other users.

FFT-based CDMA RAKE receiver system and method

A synchronization system and method for obtaining frame, carrier, and sampling synchronization of an input OFDM modulated digital signal having a pseudoperiodic second symbol. The system includes an apparatus for obtaining frame synchronization, and the apparatus includes an envelope detector to detect the first symbol of the input signal, and a differentiator connected to the envelope detector to detect the second symbol. The differentiator includes a first filter having a transfer function H(z)=(1+z.sup.-1) and a second filter having a transfer function H.sub.p (z)=(1-z.sup.-n/2 +z.sup.-n -z.sup.-3n/2), where n equals to a number of samples in the input signal. Synchronization of the carrier frequency offset is obtained by first obtaining the fractional carrier frequency offset, and then obtaining the integral carrier frequency offset through a matched filtering process. Sampling frequency synchronization is obtained through the matched filtering process for determining integral carrier frequency offset.

Synchronization method and system for a digital receiver

A synchronization system for an input signal having a plurality of OFDM symbols, each symbol having at least one guard interval, includes a correlation device for providing a product of the input signal with a complex conjugate of the input signal delayed for a predetermined period, an arithmetic device for obtaining an argument value of the product, and a detection device for detecting a transition in phase values of an output of the arithmetic device, wherein the transition occurring when the phase value in one portion of the symbol duration is substantially smaller than another portion of the symbol duration. The system additionally includes a power estimator for detecting an OFDM symbol frame of the input signal with reference to a predetermined threshold, and a device for estimating fractional carrier frequency offset.

Synchronization method and apparatus for guard interval-based OFDM

A demodulating system for estimating frequency offset and sampling time error by a Fast Fourier Transform operation, which receives a modulated signal sent from a GMSK (Gaussian Low-Pass Filtered Minimum Shift Keying) or a MSK (Minimum Shift Keying) transmitter and demodulates the signal. The demodulating system uses a Fast Fourier Transform converter to obtain frequency offset and sampling time error by applying to it an initial demodulated result generated from a discriminator or a phase differentiator.

Demodulating system for MSK and GMSK signal using a fast fourier

In a mobile cellular communication system, a base station is wired to a Local Area Network (LAN), and has wireless communication with a plurality of mobile stations. Multipath fading is substantially reduced in the system by utilizing antenna diversity techniques at the base station and each of the plurality of mobile stations. The combination of the independent operation of antenna selection diversity at both a base station and a mobile station results in the selection of the best propagation path between the two stations.

Diversity transmission strategy in mobile/indoor cellula radio

Methods for handoff in a wireless communication network including a local area network connected to a plurality of base stations, each of which has a geographic area, defined as a cell, within which mobile stations can communicate with a base station, with each such base station being capable of performing bidirectional wireless communication with one or more of said mobile stations under control of a controller, with communication between base stations and mobile stations being performed by frequency hopping, with there being n available frequency hopping channels in a fixed frequency band, with each channel being of a same fixed duration and having a fixed frequency different than another channel. The handoff method employs structure and techniques for determining by a mobile station that the quality of transmission between itself and a current base station has degraded below a predetermined performance level, structure and technique for the mobile station to listen to each of successive frequency channels for a duration substantially less than the fixed duration of a channel until it senses a transmission from another base station, and structure and techniques for transferring control of the mobile station to another base station in response to the sensed transmission.

Handoff monitoring in cellular communication networks using slow

A method for use in multicellular communication network system of the type having base stations and a plurality of remote stations. The method achieves reliable and fault tolerant synchronization between the stations in a call when a frequency hopping technique is used. The method includes steps for acquiring the frequency hop sequence by remote station and tracking the frequency hop sequence after acquisition in order to stay in synchronism. The method also provides for recovering from loss of synchronism and for staying in synchronism.

Radio communications system with fault tolerant frequency hopping

A control system for automated management of frequency-hopping in a radio network. The system includes a Wireless Network Manager (WNM) or Controller and a Wireless Control Agent (WCA), which control the distribution and maintenance of hopping patterns in the radio network. In a single cell network, the WNM and the WCA are included in a single base station. In a multiple cell network, the WNM is in a specific station on a LAN, and a WCA is located in each base station on the LAN. In each instance, the WNM is a centralized managing station and the WCA acts as a cell controller.

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Hsinchu, Taiwan

Chia-Chi Huang