This paper describes design and implementation of an OFDM-based digital video broadcasting system test platform for multichannel ultra-high definition (UHD) broadcasting services. The developed digital video broadcasting system test platform has been installed in commercial broadcasting station, and trial broadcasting service of the system has been performed through the commercial in-service network. For the performance measurement, field test is also executed. To evaluate the practical performance of the implemented system, a commercial broadcasting set-top box is used. Furthermore, by using measurement receiver, various system performances have been evaluated such as BER, PER, and CNR. Because high efficiency video coding (HEVC) can successfully transmit multimedia contents with a raw data rate of 51.6 Mbps, a multichannel UHD service can be serviced in a single physical 6MHz channel.

This paper presents an efficient closed-loop power control algorithms for the next generation mobile satellite systems. Although we could not see any active role of a satellite system in the 3G networks, satellite system will provide strong advantages in future systems for certain applications. Because a satellite link has longer round trip delay than a terrestrial link, we need time delay compensation- and efficient channel estimation algorithms that would make the satellite component especially efficient. After presenting the satellite radio interface of the 3G system, we suggest powerful power control which need to be considered in the beyond 3G systems.

This paper presents the efficient structure and parameter optimization of downlink beamforming transmitter in OFDMA/TDD system. To design downlink beamforming transmitter for multiple transmit antennas, an efficient beamforming structure for multiple users and the choice of word-length of main data path are critical in the aspect of its performance and hardware complexity. We propose an efficient beamforming scheme, which calculates the weights for corresponding user in a subcarrier unit of IFFT input at high speed to reduce the hardware complexity and processing time of transmitter and receiver. Also, we obtain the word-length of main data path and other design parameters by simulation analysis. The proposed architecture could reduce the memory size proportional to the maximum number of users per frame, and the processing time of an OFDM symbol at the receiver of base station without the need of an additional processing time for calculating the weights at the transmitter.

This letter presents a mathematical model for the statistics of wideband code-division multiple-access signals which experience multipath fading. The statistics are obtained from numerically generated signals, and are then modeled with an offset noncentral chi distribution with three degrees of freedom. The mathematical model is tested against the numerically generated data by the use of a chi-square goodness-of-fit test.