National Yang Ming Chiao Tung University

Institute for Information Industry

Industrial Technology Research Institute

Bell Communications Research, Inc.

David W Lin

Kun-Chien Hung

Chun-Che Chien

Chun-Jung Wu

Yi-Ting Lin

Youn-Tai Lee

Shih-Jung Lu

Tsung-Yu Tsai

Tzu-Hsien Sang

I-Chou Chung

Hai-wei Wang

Cheng-Yi Huang

Yen-Kai Wang

Ngan King N

Yu-Sheng Guo

I-Chou A Chung

Chih Peng Fan

A communication system includes at least one transmitting unit and at least one receiving unit. The at least one transmitting unit is configured to transmit at least one input signal after precoding it with at least one precoding matrix. The at least one receiving unit wirelessly coupled with the at least one transmitting unit is configured to receive the at least one precoded input signal, and generate at least one channel quality signal corresponding to the at least one precoded input signal, in which the at least one transmitting unit generates at least one magnitude information estimate or at least one phase information estimate or at least one of both for at least one channel state information according to the at least one channel quality signal, the at least one precoding matrix and at least one noise size signal.

Communication system and channel estimating method thereof

A two-way relay, a wireless apparatus and a signal processing method thereof are provided. The two-way relay comprises a transceiver and a processor. The transceiver receives a relay receiving signal including a first terminal transmitting signal transmitted by a first wireless apparatus and a second terminal transmitting signal transmitted by a second wireless apparatus. The processor, which is electrically connected to the transceiver, uses a mapping function to transform the relay receiving signal into a relay signal and enables the transceiver to broadcast the relay signal.

Two-way relay, wireless apparatus and signal processing method thereof

A two-way relay transmission apparatus applied to multi-input multi-output communication systems that combines signals received from the terminals and performs a modulo operation to the combined signal to concentrate the signal points towards the center of the constellation. And then, the modulo version of the combined signal is broadcasted. As a result, the peak and average relay transmission powers can be reduced.

Two-way relay transmission method and apparatus applied to multi-input multi-output communication systems

A relay gain assignment method and a relay gain assignment device are provided. The method and the device are performed in a MIMO relay system comprising M spatial degrees of freedom and L relay terminals, wherein M and L are positive integers. The relay gain assignment method comprises the steps of: (a) defining a system model for the MIMO relay system, wherein the system model comprises a relay-connected noise and a destination-connected noise; (b) calculating power of the relay-connected noise and power of the destination-connected noise; (c) determining the dominating one between the power of the relay-connected noise and the power of the destination-connected noise; (d) defining a proper noise dominating model based on the determination result of the step (c); (e) calculating L relay gains for the L relay terminals; and (f) assigning each of the relay gains to the corresponding relay terminal of the MIMO relay system.

Relay gain assignment method and relay gain assignment device

A method for processing a frequency division multiplexing signal transmitted in a channel is provided. The method includes the steps of a) receiving the frequency division multiplexing signal having a residual intercarrier interference (ICI) and a channel noise and transmitted by plural subcarriers; b) performing a cyclic prefix removal and a discrete Fourier transform for the frequency division multiplexing signal to obtain a frequency-domain signal; c) analyzing the frequency-domain signal to obtain a plurality of correlation values for the residual ICI and the channel noise; and d) performing a communication signal processing for the frequency division multiplexing signal based on at least one of the plural correlation values.

System and method for processing a frequency division multiplexing signal

A power distribution apparatus (PDA), a power distribution method, and a non-instant computer readable medium thereof are provided. The PDA is used in a relay transmission system (RTS) comprising a mobile station (MS), a relay station (RS) and a base station (BS). The MS communicates with the BS through the RS. The PDA may communicate with the MS, BS and RS. The PDA computes optimum transmission parameters of the MS and BS and an optimum relay forward parameter of the RS according to a power threshold, transmission information of the RTS, an optimum condition and an algorithm. Accordingly, the MS, RS and BS may determine the optimum transmission power of the MS, RS and BS according to the optimum transmission parameters and the optimum relay forward parameter respectively.

Power distribution apparatus, power distribution method, and non-instant computer readable medium thereof

A preamble sequence detection and integral carrier frequency offset estimation method for OFDM/OFDMA wireless communication systems by formulating integral carrier frequency offset estimation and preamble sequence detection as a signal detection problem in multi-channel interference, obtaining the theoretically optimal solution, and deriving simplified, approximately optimal solutions, in which frequency-domain filtering is employed to calculate the required correlation values, which can drastically reduce the high computational complexity of the original theoretically optimal solution but result in little impact on precision. In addition, several further simplified algorithms are provided, some of which can even eliminate the use of multipliers. The using of frequency-domain filtering has high extensibility in application to related signal sequence detection problems.

Preamble sequence detection and integral carrier frequency offset estimation method for OFDM/OFDMA wireless communication system

A communication apparatus, a method, and a tangible machine-readable medium thereof for processing ranging interference of an orthogonal frequency division multiplexing (OFDM) signal. The communication apparatus comprises a receiving unit, a processing unit, and a mask generating unit. The receiving unit receives the OFDM signal having a plurality of OFDM symbols. The processing unit estimates a delay value and an energy value of at least one ranging code according to the OFDM symbols. The mask generating unit generates a mask function according to the delay value and the energy value. Finally, the processing unit synthesizes the ranging interference in the OFDM signal and removes it according to the mask function.

Communication apparatus, method, and tangible machine-readable medium thereof for processing ranging interference of an orthogonal frequency division multiplexing signal

This invention discloses a method for OFDM and OFDMA channel estimation via phase-rotated polynomial interpolation and extrapolation (inter/extra-polation). For complexity reason, polynomial inter/extra-polation is an often considered method for channel estimation in orthogonal frequency-division multiplexing (OFDM) and orthogonal frequency-division multiple access (OFDMA) systems, in which the simplest choice is linear inter/extra-polation. But the performance of this method depends on the accuracy of symbol timing estimation as well as the channel delay spread. The invention mitigates the problem by adding a linear phase factor to polynomial inter/extra-polation, which corresponds to adding a delay (also called delay shift) in the time domain.

Method for OFDM and OFDMA channel estimation

The present invention relates to a channel estimation technique for multi-carrier system which uses pilot signal to first obtain pilot subcarrier channel responses, then estimate the mean delay and the root-mean-square delay spread of the channel, and then uses interpolation to obtain the channel responses of arbitrary subcarriers. The present invention is able to perform channel estimation and to accurately estimate various channel delay parameters (such as the initial delay, the mean delay, and the root-mean-square delay spread) with very low quantity of pilot signal and with low computational complexity. In addition, the present invention has broad applicability, as it does not require the channel power-delay profile to be of certain specific types and it can operate in systems where pilot subcarriers have an irregular configuration.

Channel estimation technique for multi-carrier system

A gain adjustment apparatus, a gain adjustment method, and a tangible machine-readable medium thereof for a multiple input multiple output (MIMO) wireless communication system are provided. The MIMO wireless communication system comprises source antennas, destination antennas, relay stations (RSs) and a relay transmission power limit value. The gain adjustment method comprises the following steps: adjusting the gain of one single RS according to a gain calculation; multiplying the gains of other relay stations by a scaling value for adjustment. According to aforesaid method, the present invention can increase the system capacity of the MIMO wireless communication system.

Gain adjustment apparatus, method, and tangible machine-readable medium thereof for a multiple input multiple output wireless communication system

A scalable QAM system and communication method. High-level QAM signals are broadcast from a transmitter. The transmitter comprises a scalable frame structure in a MAC layer and a bitmap method in a physical layer transmitting modulated signals with data distributed in different bit positions. Each client determines whether to demodulate all the received data on the bit plane or only a portion of the data in certain bit positions according to the transmission quality (SNR) of the received signal, in order to acquire a lower bit error rate and improve the efficiency of the transmission bandwidth.

Scalable QAM system and method

In a low bit-rate video coder which processes the pels in each video frame on a block-by-block basis using a hybrid differential pulse code modulation and discrete cosine transformation as defined in CCITT Recommendation H.261, the blocks are processed in a sequential order, which in areas of high activity may cause the output buffer to approach its capacity level. In response, the adjoining blocks are more coarsely quantized with resultant image degradation. Improved coding performance is achieved by processing the blocks in a pseudo-random order which disperses the high activity blocks among the more quiescent blocks. As a result the buffer is less likely to reach its maximum capacity, and the quantization levels will remain essentially constant throughout coding of the frame, thereby improving image quality.

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Hsinchu, Taiwan

David W Lin