Electronics and Telecommunications Research Institute

Sang In Cho

Kyu Min Kang

Byung Jang Jeong

Jae Cheol Park

Kwang Roh Park

Sangsung Choi

Dong Hun Lee

Yong Seok Choi

Min Soo Kang

Sung Woo Choi

Kyu-Min Kang

Sang Sung Choi

Hyung Jung Kim

Haeng Sook Ro

Gwang Moon Park

Disclosed is a method and apparatus for generating a radar signal, in which performance of radar detection is ensured while increasing a spectrum efficiency in a radar network. The method comprises generating a set of frequency-modulation waveforms, generating an orthogonal code set, generating a set of coded frequency-modulation waveforms through element operation between the set of frequency-modulation waveforms and the orthogonal code set, calculating an objective function for the set of frequency-modulation waveforms with regard to a different set of coded frequency-modulation waveforms and previous sets of coded frequency-modulation waveforms, and selecting a current polyphase code set as an optimized polyphase code set when a result of current calculation is better or smaller than a result of previous iteration, and performing phase perturbation by replacing an element randomly selected in the current polyphase code set selected as the optimized polyphase code set with another admissible-phase element.

Method and apparatus for generating orthogonal radar signal based on frequency modulation

Disclosed are a variable antenna and an apparatus for detecting a radio signal. The variable antenna includes: a first receiving unit including at least one liquid metal antenna element; a second receiving unit including at least one liquid metal antenna element having a length different from a length of the first receiving unit; and a gain control unit configured to electrically adjust lengths of the liquid metal antenna elements for one of the first receiving unit and the second receiving unit according to the frequency of a received signal, wherein each antenna array realized by the liquid metal antenna elements of the first receiving unit and the second receiving unit is arranged in a single bay.

Variable antenna and apparatus for detecting radio signal

Disclosed are an available channel information sharing system and an available channel information sharing method, and an available channel information sharing system and an available channel information sharing method based on positional information and area information. The available channel information sharing system sharing available channel information for each unit region includes: a server; a white band device placed in the unit region; and a white band sensing device creating positional information and transmitting the created positional information to the server, receiving unit region information corresponding to the positional information from the server, and transmitting first available channel information based on channel information of a sensed broadcasting signal to the white band device.

Available channel information sharing system and available channel information sharing method

Disclosed is a method for calculating a radio coverage in a wireless device for calculating a protective distance so as not to allow a secondary user sharing a frequency with a primary user to have an effect of radio interference on the primary user, the method including: calculating a transmission power of a wireless signal transmitted through the frequency by the secondary user; determining a region affected by the wireless signal based on the transmission power of the secondary user; calculating an average ground clearance of the determined region; calculating a height of an installation place of an antenna of the secondary user from the average ground clearance; and calculating the height of the antenna from the average ground clearance by adding a length of the antenna of the secondary user to the calculated height and calculating the radio coverage based on the height from the average ground clearance.

Method for calculating radio coverage in wireless device

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.

Method and device for sensing frequency for OFDM systems

Disclosed is a method of allocating radio resources, including: acquiring available channel information of a cognitive radio small cell; analyzing a channel characteristic based on the available channel information and dividing a required transmission rate of the cognitive radio small cell into required transmission rates for each available channel; and performing a power control for each available channel based on the divided required transmission rates for each available channel. The method of allocating radio resources may be performed under an interference environment in which a plurality of cognitive radio small cells is present and the plurality of cognitive radio small cells shares an available channel.

Method of allocating radio resources and apparatus of allocating radio resources in cognitive radio small-cell networks

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.

Apparatus and method of calculating available channels considering priority in TVWS

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.

White space use system with connecting cognitive signal

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.

Synchronization error tracking device and method thereof

Provided is a method for transforming data using a look-up table. The method includes the steps of: (a) mapping pre-processed input binary data to a constellation diagram divided into four quadrants to output a first complex number; (b) performing addition/subtraction operations between real numbers and between imaginary numbers with respect to the first complex number and a second complex number; and (c) reading a fourth complex from a look-up table in response to the first complex number, the second complex number and a third complex number, the look-up table outputting the fourth complex by performing a subtraction operation on multiplication results between real numbers and between imaginary numbers and an addition operation on multiplication results between the real numbers and the imaginary numbers with respect to the result value of the step (b) and the third complex number. Accordingly, it is possible to reduce the hardware size at the time of IFFT/FFT design and to provide a high-speed, low-power operation.

Method for transforming data by look-up table

A 2N-point and N-point FFT/IFFT dual mode processor is provided. The processor includes a butterfly operator, the first and second MUXs, and the first and second N-point FFT processors. The butterfly operator receives 2N data and butterfly-operates on the received 2N data when receiving a control signal '0' from the controller. The first and second MUXs respectively receive results from the butterfly operator to output the results in an increment of N when receiving a control signal '0' from the controller, and respectively outputs different N data when receiving a control signal &#x2018;1&#x2019; from the controller. The first and second N-point FFT processors N-point FFT operate on the results from the first and second MUXs and respectively output the same under control of the controller. Since the N-point FFT operation can be simultaneously performed two times at a receiver, the performance of the receiver can be enhanced.

Growing community of inventors

Daejeon, South Korea

Sang In Cho