Korea Advanced Institute of Science and Technology

Samsung Electronics Co., Ltd.

Hwang-Soo Lee

Moo-Hong Lee

Byung-Jik Keum

Jeong-Han Jeong

Young-Serk Shim

Jung-Hoon Cheon

Young Serk Shim

Il-Song Han

Chang-Hyun Nam

Jae-Ki Lee

Jung-Keun Kim

Soo-Bin Lee

There are provided an apparatus for synchronizing an OFDM signal using an open-loop frequency synchronization method, which can estimate and compensate for various types of frequency errors generated in a frequency modulation broadcasting/communication system to which the open-loop frequency synchronization method is applied, and a frequency offset estimation scheme using the apparatus. To this end, the apparatus for synchronizing an OFDM signal using the open-loop frequency synchronization method comprises a time offset estimator, a time offset compensator, a fractional frequency offset estimator, an integer frequency offset estimator, a frequency offset controller and a frequency offset compensator. Accordingly, in the OFDM demodulation broadcasting/communication system using the open-loop frequency synchronization method, a frequency offset, which is generated due to the carrier frequency difference between a transmitter and a receiver, a frequency shift generated due to the mobile environment of a receiver, the temperature characteristic of a local oscillator, and the like, can be estimated and compensated.

Apparatus for synchronizing OFDM signal using open-loop frequency synchronization method and frequency offset estimation scheme using the apparatus

Disclosed are an apparatus and a method for preventing data read error for OFDM symbol demodulation. An average time synchronization offset estimating unit estimates average time synchronization offset between a pilot symbol of a time synchronized data frame and pilot symbols of data frames next to the time synchronized data frame. A data buffer control unit acquires a start location of a data frame to be read using the estimated average time synchronization offset, and controls reading of written data frames using the acquired start location information of the data frame to be read. In the apparatus and the method, a data buffering using a ring buffer construction may compensate time synchronization offset of samples containing real data in an OFDM symbol and prevent an erroneous read error in order to improve a receiving performance of a receiver.

Apparatus and method for preventing data read error for orthogonal frequency division multiplexing symbol demodulation

There is provided a direct memory access apparatus and a direct memory access method. The direct memory access apparatus of the present invention comprises: a variable transmission rule map unit for setting a transmission rule with a variable block length and a variable block interval as a unit of memory transmission rule; a direct memory access unit for sending data line of the variable block length and the variable block interval, in case of access to the unit of memory by using the unit of memory transmission rule determined by the variable transmission rule map unit; and an interface unit for retrieving the unit of memory transmission rule, which is necessary for sending the data line of the variable block length and the variable block interval, from the variable transmission rule map unit and sending the unit of memory transmission rule to the direct memory access unit.

Direct memory access apparatus for sending data stored in memory separately from an operation of a main processor and direct memory access method using the same

There is provided an apparatus for receiving a T-DMB signal. The apparatus for receiving a T-DMB signal comprises an input buffer receiving and buffering a T-DMB signal comprising a null symbol and a phase reference symbol (PRS); an initial synchronizing unit estimating and compensating for time and frequency offsets of the T-DMB signal using the null symbol and the PRS; a frame tracking unit performing estimation of the time offset and measurement of a strength of an output signal from the input buffer; an OFDM signal demodulating unit performing I/Q demodulation, frequency compensation, OFDM demodulation and de-interleaving with respect to an output signal of the frame tracking unit; a channel decoding unit performing channel decoding with respect to an output signal of the OFDM signal demodulating unit and checking quality of the channel-decoded signal; and a controller controlling operations of the initial synchronizing unit, the OFDM signal demodulating unit and the channel decoding unitbased on the strength of the signal measured by the frame tracking unit and the quality of the signal checked by the channel decoding unit. Accordingly, unnecessary calculating processes arc reduced by measuring the strength and quality of an input signal, thereby maximizing power efficiency of the apparatus.

Apparatus for receiving T-DMB signal and method of operating the same

Provided are a system and a method for allocating resources in a communication system. The method includes mapping a Transmission Time Interval (TTI) class according to channel information transmitted from a mobile station and service class information of the mobile station; and allocating resources by dynamically configuring a frame based on the mapped TTI class.

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Daejeon, South Korea

Hwang-Soo Lee