Abstract: Disclosed are an apparatus and a method of calculating available channels considering a priority in a TVWS. An apparatus for calculating available channels considering a priority in a TVWS according to the present invention includes: a communication module configured to receive a request for information on usable available channels from a TV Band Device (TVBD); an available channel calculation unit configured to calculate one or more available channels usable by the TVBD based on one or more predetermined reference parameters according to the request; a priority assignment unit configured to assign a priority to each of the calculated available channels, generate an available channel list including the available channels to which the priorities are assigned, and provide the TVBD with the generated available channel list; and a database configured to store the available channels, to which the priorities are assigned, calculated for each TVBD.

Abstract: Provided is a white space use system using a connection recognition signal, which is associated with technology that enables white space devices to search for and to use an available frequency band in a digital broadcasting system. In particular, provided is a white space use system using a connection recognition signal that enables even devices incapable of autonomously searching for an available channel to safely use a white space in interaction with white space devices.

Abstract: Provided is an apparatus and method for controlling a transmission output of a radio device using a television (TV) band based on a frequency band, the apparatus including a frequency band selecting unit to select frequency bands to be compared, a radio wave attenuation calculation unit to calculate a radio wave attenuation for each of the selected frequency bands, and a transmission output control unit to automatically control the transmission output of the radio device using a TV band based on a difference value among the calculated attenuation values. According to an example embodiment, it is possible to extend a service area while sufficiently protecting a service being provided in the TV band, thereby realizing an efficient use of frequency resources.

Abstract: Disclosed are an apparatus and a method of calculating available channels considering a priority in a TVWS. An apparatus for calculating available channels considering a priority in a TVWS according to the present invention includes: a communication module configured to receive a request for information on usable available channels from a TV Band Device (TVBD); an available channel calculation unit configured to calculate one or more available channels usable by the TVBD based on one or more predetermined reference parameters according to the request; a priority assignment unit configured to assign a priority to each of the calculated available channels, generate an available channel list including the available channels to which the priorities are assigned, and provide the TVBD with the generated available channel list; and a database configured to store the available channels, to which the priorities are assigned, calculated for each TVBD.

Abstract: Provided is a frequency sensing method and apparatus in an orthogonal frequency division multiplexing (OFDM) system. Provided is a method of sensing a frequency of a received signal that is received from an outside in order to perform one of a plurality of radio communications. An OFDM apparatus may need to inspect a required frequency band before or after performing one of the plurality of radio communications, and to determine whether the frequency band is being used by another radio communication.

Abstract: An apparatus for detecting a signal in a common frequency band includes: a signal processor configured to extract a selected band signal from received wireless signals by filtering the received wireless signal based on a frequency selection control signal, convert the extracted signal to a baseband signal, and detect a predetermined signal; a sensing signal determiner configured to determine existence of the signal, output a determination result, and outputs a frequency selection generating signal when the predetermined signal is absent; and a frequency selection controller configured to output the frequency selection control signal by selecting a target band among a plurality of previously decided bands.

Abstract: The present invention relates to a system and method for managing resources, which involve managing a plurality of frequency resources in a communication system including a plurality of systems not having rights to use a first frequency band.

Abstract: Provided is an apparatus and method for detecting a packet of a zero-padded OFDM signal, which are capable of determining if a packet exists in a reception (RX) signal by comparing a cross-correlation value of an OFDM signal delayed by a predetermined sample time, e.g., a zero-padded sample time, with a power value of the RX signal, thereby increasing a packet detection probability and preventing a false alarm. The packet detecting apparatus includes: a cross-correlation calculator for calculating a cross-correlation value of a reception signal received from the outside and delaying the calculated cross-correlation value by a predetermined sample time; a power calculator for calculating a power value of the reception signal; and a packet detector for determining if a packet exists in the reception signal by comparing the delayed cross-correlation value with the calculated power value, and detecting the corresponding packet.

Abstract: A parallel equalizer for a DS-CDMA UWB system and method thereof are provided. The parallel equalizer includes: a filter block for filtering a training input signal in a ‘training mode’, and filtering the plurality of input signals in parallel in a ‘symbol decision mode’; a symbol decision block for obtaining a symbol error based on a output from the filter block and a training symbol in the ‘training mode’, and estimating a transmission symbol for each of the input signals in the ‘symbol decision mode’, obtaining an error of one among the estimated transmission symbols for a symbol error calculating input signal; and an weight update block for updating a filter tap coefficients of the filter block based on the training input signal or the symbol error calculating input signal and the symbol error and transmitting the updated filter tap coefficients into the filter block.

Abstract: Provided is a method and apparatus for acquiring OFDM synchronization even when it fails to detect a plurality of symbols at an initial stage. In the method, a frequency is adjusted to a first frequency band and a cross correlation value between a received preamble symbol and a preset preamble symbol is calculated. When the calculated cross correlation value is larger than a predetermined reference value and is first detected, frequency hopping is performed to receive subsequent symbols and cross correlation values to the subsequent symbols are reexamined. When the reexamined cross correlation value larger than the predetermined reference value is detected, timing synchronization, frequency offset estimation, and frame detection are performed.

Abstract: An apparatus for detecting a signal in a common frequency band includes: a signal processor configured to extract a selected band signal from received wireless signals by filtering the received wireless signal based on a frequency selection control signal, convert the extracted signal to a baseband signal, and detect a predetermined signal; a sensing signal determiner configured to determine existence of the signal, output a determination result, and outputs a frequency selection generating signal when the predetermined signal is absent; and a frequency selection controller configured to output the frequency selection control signal by selecting a target band among a plurality of previously decided bands.

Abstract: Provided are a terminal and a base station, and a frequency sensing method thereof. The terminal or the base station may filter a frequency band needing frequency sensing in the entire frequency band where the terminal or the base station may receive an input signal. It is possible to enhance a detection performance and rate of signals by applying frequency sensing to the filtered frequency band.

Abstract: Provided is a synchronization error tracking device and method. The method and system estimates and corrects the synchronization error generated by time and frequency offsets during the data transmission interval and uses a module designed for initial synchronization or channel estimation without adding a new correlation operator. Further, a combining mark value and a synchronization position value acquired during the synchronization process are used.

Abstract: Provided is an apparatus and method for controlling a voltage gain in an ultra wideband receiving apparatus. The apparatus includes a register for storing an Automatic Gain Control (AGC) value detected in a section where an AGC operation control signal is “ON”; and a voltage gain controller for generating a voltage gain control value by reading the AGC stored in the register during a section where a reception enable signal is “ON”, and transferring the generated voltage gain control value to a voltage gain amplifier.

Abstract: Provided is an apparatus and method for detecting a time-frequency code in an MB-OFDM UWB system. The apparatus includes a controller for providing a band selection signal to the RF receiver and outputting a preamble selection signal at regular symbol periods to calculate a cross correlation value for a predetermined time period more than a beacon frame interval when a time-frequency code search start signal is received; and a cross correlator for storing information on preamble patterns, selecting a preamble stored depending on the preamble selection signal, and calculating a cross correlation value for a digital signal transferred through the RF receiver, wherein the controller determines a time-frequency code using a preamble where a peak occurs as a time-frequency code that is currently in use when a peak signal is inputted based on the calculated cross correlation value, and transmits the determined time-frequency code to the MAC receiver.

Abstract: Provided are a high speed and low power fixed-point multiplier and method thereof. The multiplier includes: a partial product calculation unit for dividing input data into a plurality of bit groups, each bit group having a predetermined number of bits, generating partial products by independently multiplying a fixed coefficient for each bit group, and summing partial products included in a corresponding bit group, to thereby generate a summed partial products; and an adding unit for adding the summed partial products of each bit group generated from the partial product calculation unit.

Abstract: There is provided an apparatus for detecting a preamble packet in an orthogonal frequency-division multiplexing (OFDM) system, including: a cross-correlation calculating means for calculating a cross-correlation value between a received signal and previously stored preamble pattern values for an OFDM symbol region (N-point); a delay means for delaying the calculate cross-correlation value as much as a M-point interval; a receiving power measuring means for measuring a receiving power for the guard interval; and a dividing means for calculating a final cross-correlation value by dividing the delayed cross correlation value by the measured power.

Abstract: Provided is a synchronization error tracking device and method. The method and system estimates and corrects the synchronization error generated by time and frequency offsets during the data transmission interval and uses a module designed for initial synchronization or channel estimation without adding a new correlation operator. Further, a combining mark value and a synchronization position value acquired during the synchronization process are used.

Abstract: Provided is a method for adjusting Fast Fourier Transform (FFT) window positioning in a Multi Band Orthogonal Frequency Division Multiplexing Ultra-Wideband (MB-OFDM UWB) system. The method includes the steps of acquiring an initial FFT window position and a frequency hopping position, demodulating a received signal by using the initial FFT window position and the frequency hopping position acquired in the acquiring step, transmitting received data information to a Media Access Control (MAC) layer with a reception frame (RX frame) structure and judging at the MAC layer whether or not a packet error is occurred based on Frame Check Sequences (FCSs), and if no packet error is occurred, returning to the demodulating step, and if the packet error is occurred, changing a register map by using a predetermined interface line in a MAC-physical layer (MAC-PHY) interface to thereby adjust the FFT window position and the frequency hopping position, and then returning to the demodulating step.

Abstract: An FIR filter of a DS-CDMA UWB modem transmitter and a control method thereof are disclosed. The FIR filter includes an LUT control device for outputting a resultant value of “0” to all adders if data values corresponding to upper three chips H2, M2 and L2 and lower three chips H, M and L are “000000”, and discriminating which group between a first group and a second group the upper/lower data values belong to if the upper/lower data values are not“000000”. The LUT control device provides upper or lower LUT values to the adders using the upper or lower LUT values as they are, or converts the upper or lower LUT values into 2's complements and provides the converted values to the adders according to the discriminated first or second group.