Abstract:
본 발명은 공공 및 사설 인터넷 주소를 동시에 수용하기 위한 위성 인터넷 접속 중심국의 구조 및 그 운용 방법에 관한 것이다. 인터넷을 사용하고자 하는 호스트의 급속한 증가로 인한 인터넷 주소의 고갈 현상때문에 인터넷 접속 서비스를 제공하는 사업자는 적은 수의 공공 인터넷 주소를 할당받아 동적으로 인터넷을 요구하는 사용자에게 할당하는 방식을 사용하고 있으나, 할당받은 공공 인터넷 주소의 갯수에 따라 접속 가능한 사용자의 수에 제약을 가져온다. 다른 방안으로 사설 인터넷 주소를 사용하여, 내부에서는 사설 인터넷 주소를 사용하고 인터넷을 접속할 때 가용한 공공 인터넷 주소로 변환하여 서비스를 제공하지만 사설 인터넷 주소를 사용하는 가입자는 서비스에 많은 제약을 갖는다. 본 발명에 따른 위성 인터넷 접속 중심국은 기존 시스템들의 변경없이 사설 인터넷 주소와 공공 인터넷 주소를 모두 수용하므로써 사용자들에게 공공 인터넷 주소나 사설 인터넷 주소를 할당하여 다양한 형태의 서비스를 제공하여 줄 수 있는 네트워크 구성을 가능하게 한다.
Abstract:
A frequency error corrector in a mobile station of a satellite communication system simultaneously corrects a frequency deviation of a satellite relay station and a frequency error generated in a conversion chain of an earth station upward/downward frequency, as well as doppler frequency deviation caused by a satellite motion. The frequency error corrector includes: upward frequency converter(3); a frequency converter(4); outbound demodulator(5) for detecting a receiving frequency error of a terminal station; a data divider(7) for separating a receiving frequency error information of the outbound signal of a center station; a frequency correction information proider(6) for receiving a receiving frequency error information of the terminal station and a receiving frequency error information of the center station, and providing a frequency correction information; an inbound modulator(8) for receiving an inbound signal transmission frequency correction information, and modulating the data to an inbound signal; a traffic demodulator(10) for correcting a frequency according to a traffic signal receiving frequency correction information; a traffic modulator(9) for correcting a frequency according to a traffic signal transmitting frequency correction information; and a reference frequency oscillator(1) for synchronizing the above elements.
Abstract:
The frequency error correcting device in a district center of a satellite communication system is provides with: an upward frequency converter (5) converting the upward frequency; a downward frequency converter (7) converting the downward frequency; an out-bound modulator (6) generating a continuous time division multiplexing carrier wave to output it to the upward frequency converter (5); an outbound demodulator (10) connected to an output terminal of the downward frequency converter (7) to detect a frequency error of an outbound signal received in the district center; a data inserting unit (9) inputting district center reception frequency error information to insert it into an out-bound time division multiplexing frame; an inbound modulator (8) connected to an output terminal of the downward frequency converter (7), and inputting district center reception frequency error information to modulate an inbound signal; a frequency error information providing unit (11) collecting district center frequency error information detected in the outbound modulator (10) to provide it to the data inserting unit (10) and the inbound modulator (8); and a reference frequency oscillator (3) oscillating a reference frequency to synchronize the upward frequency converter (5), the downward frequency converter (7), the outbound modulator (6), the inbound modulator (8) and outbound modulator (10).
Abstract:
a VCO(22) for generating a frequency; a coupling means(10) for partially coupling a signal, and mostly passing the signal; a first mixer(11) for mixing a frequency; a LPF(12); a first amplifier(13) for amplifying an input signal; a first power divider(19) for dividing a reference frequency signal; a frequency mixer(15) for mixing a frequency according to a frequency control command; a second mixer(14) for mixing a frequency; a BPF(16); a second amplifier(17) for amplifying an input signal; a phase detection means(18) for detecting a phase difference; a loop filter(20) for removing a high frequency component, and integrating it; and a second power divider(21) for dividing an input. Accordingly, the ku-band frequency mixer reduces a system size, reduces a production cost, adds a frequency multiplier to an output terminal.