Agency for Science, Technology and Research

Other

Ntt Docomo, Inc.

National Univ. of Singapore

Ying-Chang Liang

Yonghong Zeng

Francois Po Shin Chin

Mamoru Sawahashi

Hiroyuki Atarashi

Zhongding Lei

Po Shin Francois Chin

Xiaoming Peng

Choo Leng Koh

Francois Chin

Francois Chin Po Shin

Appukuttan Nair Saraswathy Amma Madhukumar

A transmitter comprises a first spreading unit configured to multiply each of multiple data symbols with a first spreading code sequence of a first spreading factor; a compression and repetition unit configured to compress output signals of the first spreading unit in time domain and repeat the compressed signal L times (where L is a natural number greater than or equal to 2); a phase modulation unit configured to multiply the compressed and repeated signal with a user dependent phase and output a data block consisting of L sub-blocks; a second spreading unit configured to replicate the data block according to a second spreading factor and multiply each set of the replicated sub-blocks with a second spreading code sequence of the second spreading factor to produce a two-dimensionally spread signal; and a wireless transmission unit configured to transmit the two-dimensionally spread signal using a single-carrier transmission scheme.

Two-dimensional code spreading for interleaved FDMA system

A method of determining as to whether a received signal includes a data signal is provided. The method provided includes determining a first value based on a cyclic auto-correlation of the received signal and determining a second value based on the cyclic auto-correlation of the received signal. The method provided further includes determining as to whether a received signal includes a data signal based on a comparison of the first value and the second value.

Method for determining as to whether a received signal includes a data signal

An embodiment of the invention provides a method for classifying a received signal. The method includes determining a covariance matrix of signal values of the received signal, and determining an eigenvalue matrix of the covariance matrix. The eigenvalue matrix includes the eigenvalues of the covariance matrix. A first function is determined from at least one eigenvalue of the eigenvalues of the covariance matrix. A second function is determined from at least one eigenvalue of the eigenvalues of the covariance matrix, wherein the second function is different from the first function. Dependent from a comparison between a value of the first function and a value of the second function, the received signal is classified into a signal comprising data or into a noise signal.

Method, device and computer program for classifying a received signal

A method of determining as to whether a received signal includes an information signal is provided. The method provided includes determining a covariance matrix from a received signal and transforming the covariance matrix into a transformed covariance matrix, wherein the transformation is configured such that the transformed covariance matrix is a non-diagonal matrix in case the received signal includes the information signal, wherein the non-diagonal matrix includes non-zero non-diagonal matrix elements. The method provided further includes determining a first function using at least one of the non-zero non-diagonal matrix elements of the transformed covariance matrix, determining a second function using at least one matrix element of the transformed covariance matrix, wherein the second function is different from the first function, and determining as to whether a received signal includes an information signal based on a comparison of a value of the first function and a value of the second function.

Method of determining as to whether a received signal includes an information signal

A method for downlink beamforming in a frequency-division-duplex wireless communications system comprising a base station with an antenna array and terminals that are physically remote from said base station, the method comprising the steps of: receiving at said base station antenna array combinations of arriving uplink signals from said plurality of remote terminals, estimating an uplink beamforming weight vector for each of said terminals from said combinations of arriving uplink signal; identifying uplink nulls and an uplink main beam position from said uplink beamforming weight vector; transforming each of said uplink nulls to form a corresponding downlink null; generating a downlink beamforming weight vector from all downlink nulls; and transmitting a set of information signals from said base station antenna array according to said downlink. beamforming weights.

Beam synthesis method for downlink beamforming in FDD wireless communication system

A code division multiple access downlink receiver for providing wireless communication via a wireless channel between a base station and a mobile station in which the receiver is implemented. The receiver comprises a plurality of subchannels of which each conveys at least one signal received from the base station, and a cell searcher for receiving signals in the plurality of subchannels and retrieving therefrom a common code relating to a cell. The receiver also comprises a code generator for generating a set of common and dedicated codes relating to at least one communication channel using the output of the cell searcher, and a plurality of equalizers for receiving the code generator output and equalizing the received signals in the plurality of subchannels, in which each of the plurality of equalizers includes a plurality of filters in which each of the plurality of filters corresponds to each of the plurality of subchannels, in which the length of each of the plurality of filters is lesser than the length of each of the plurality of subchannels.

Path diversity equalization CDMA downlink receiver

A method and apparatus for achieving combined beamforming and transmit diversity for frequency selective fading channels in a communication system having a base station with multiple transmit antennae and a mobile terminal with at least a single receive antenna, the method comprising the steps of: providing a signal to be transmitted; space-time encoding the signal to produce at least two separate signals, each on a respective output; feeding each output signal to a multiple access transmit processor to produce an output signal; applying respective selected transmit beamforming weights to each output signal; feeding the respective weighted signals to a signal combiner to perform a summing function of the signals and produce a signal for transmission; feeding the summed signal to each of the multiple transmit antennae for transmission; transmitting the signals over respective physical channels; receiving the transmitted signal at at least a single receive antenna; feeding the transmitted signal to a multiple access receive processor to produce an output signal; and space-time decoding the received signal.

Wireless communication apparatus and method

A code division multiple access (CDMA) system and methods for processing symbol blocks of a spread signal in both frequency and time domains are described. A transmitter () of the CDMA system spreads pilot symbols and data of the symbol blocks to derive a spread sequence. Thereafter, the spread sequence is extended with a predetermined number of chips and pulse shaped for transmission as the spread signal. A receiver () of the CDMA system receives the spread signal, removes the predetermined number of chips and then orthogonally transforms the spread signal to the frequency domain to derive a transformed signal. The transformed signal is equalized in the frequency domain to derive an equalized signal. The equalized signal is then inverse orthogonally transformed to an output in the time domain. The output is then despreaded to derive the symbol blocks.

Growing community of inventors

Singapore, Singapore

Ying-Chang Liang