Abstract:
The present invention discloses an apparatus and a method for calculating available channels by considering TV band propagation characteristics. The apparatus for calculating available channels considering TV band propagation characteristics according to the present invention includes: a communication module receiving request of usable available channel information from a TV Band Device (TVBD); a regional shape determining unit to determine the shape of a region in which the requested TVBD is located; an available channel calculator to calculate at least one available channel usable at a region in which a corresponding TVBD is located based on a preset protection spacing distance according to the determined shape of the region and to generate and provide an available channel list including the calculated available channel to the TVBD; and a database to store the at least one available channel calculated by TVBDs.
Abstract:
The present invention provides an apparatus and a method for controlling transmission output of a wireless device that automatically controls transmission output of a wireless device using a TV band according to a frequency band. The present invention is configured to include a frequency band selection unit for selecting frequency bands to be compared; a radio wave decrement calculation unit for calculating a radio wave decrement for each of the selected frequency bands; and a transmission output control unit for automatically controlling the transmission output of the wireless device using the TV band based on a difference value between the calculated radio wave decrements. According to the present invention, a service area can be widened while sufficiently protecting a service provided in the TV band, and frequency resources can be used efficiently.
Abstract:
다중 안테나 OFDM 송신기는 주파수 영역에서의 데이터 심볼들을 복수 개의 부그룹들로 나누는 부그룹 생성부; 상기 복수 개의 부그룹들 각각에 대응하는 시간 영역에서의 부분 신호들을 생성하기 위하여 상기 복수 개의 부그룹들에 대해 개별적으로 고속 푸리에 역변환을 수행하는 IFFT 수행부; 상기 부분 신호들 각각이 복수 개의 송신 안테나들 중 어느 하나로 전송될 수 있도록 상기 부분 신호들의 조합을 이용하여 적어도 둘의 OFDM 신호 후보들을 생성하는 OFDM 신호 후보 생성부; 및 상기 적어도 둘의 OFDM 신호 후보들 중 어느 하나를 선택하는 선택부를 포함한다.
Abstract:
A method and apparatus for adaptively transmitting the same data, i.e., multicast/broadcast data, according to channel quality to a receiving group including one or more terminals that request the same service in a wireless network. A base station obtains feedback on channel quality indications (CQIs) from a plurality of terminals, selects a transmission technique that satisfies desired service quality based on the COIs, and transmits data to the terminals included in a receiving group by using the selected transmission technique. The CQIs to be transmitted from the terminals in the receiving group to the base station are transmitted through a previously allocated common CQI feedback channel. In the present invention, in order to reduce a CQI feedback channel capacity, the base station does not allocate a common CQI feedback channel with respect to each reception terminal and allocates radio resources according to CQI levels. As radio resources are allocated according to CQI levels, a CQI feedback channel capacity may not be increased even when the number of terminals in the receiving group is increased and adaptive transmission may be efficiently performed.
Abstract:
PURPOSE: A method for transmitting and receiving data for the OFDM(Orthogonal Frequency Division Multiplexing) of multiple antenna and an apparatus thereof are provided to reduce the number and the complexity of IFFT(Inverse Fast Fourier Transform), when IFFT wholly is operated, by performing IFFT at each subgroup. CONSTITUTION: A subgroup generating unit(230) divides data symbols into a plurality of subgroups at a frequency domain. An IFFT performing unit(240) individually proceeds IFFT in a plurality of the subgroups to generate partial signals at a time domain which corresponds to a plurality of the subgroups. An OFDM(Orthogonal Frequency Division Multiplexing) signal candidate generation unit(250) generates at least two OFDM signal candidates using the combination of partial signals to transmit each partial signal to one of a plurality of transmission antennas. A selecting unit(260) selects at least one of two OFDM signal candidates.