Abstract:
A method of enhancing performance using hierarchical modulation in a distribution relay system is provided to expand an area of high speed data without requiring an additional time slot, thereby obtaining a gain of increasing yield. A base station transmits a signal through a hierarchical modulation method. The first relay and the second relay receive a signal transmitted from the base station. The first relay retransmits all the received signals to a terminal through the hierarchical modulation method. The second relay retransmits only a part among received signals to the terminal. The terminal performs a demodulation process.
Abstract:
A data transmission method of an MB-OFDM(Multiband Orthogonal Frequency Division Multiplexing)-based UWB(Ultra Wide Band) wireless private network is provided to relay data communication of a wireless terminal device for piconet coordination data, thereby reducing power consumption of the wireless terminal device as increasing a transfer rate. When a transmission device within a piconet demands channel time allocation for data transmission, a piconet coordinator extracts location and channel information of the transmission device and a receiving device(S10). The coordinator determines whether to relay data transmission according to a distance with the transmission device(S20). If so, the coordinator relays data communication by increasing a transfer rate of data to be transmitted, if a battery voltage of the transmission device is more than a preset reference voltage, and relays the data communication by reducing transmission power consumption of the transmission device if the battery voltage is less than the reference voltage(S30).
Abstract:
본 발명은 셀 구분을 위한 랜덤코드를 사용하여 다중셀 환경에 적합하며, 사용자를 주파수로 구분하고 데이터를 코드로 다중화하는 OFDMA/CDM을 이용하여 하향링크에서 전치 등화를 수행함으로써 시스템의 성능을 높일 수 있도록 하고, 외부 셀 간섭이 존재하는 다중셀 환경에서 송신전력이 제한되어 있는 경우 전치등화로에 효과적인 전력할당 방식으로 제로삽입 방식을 제안하는 다중셀 환경 OFDMA/CDM 기반 셀룰라 시스템의 송수신기이다. 더불어, 다중화된 심볼의 수를 조절하여 셀 영역 전체에서 유연한 서비스를 제공하는 것을 특징으로 한다. 다중셀, OFDMA/CDM, 랜덤 코드, 제로 삽입