Jeong Goo Kim

A novel subblock partition scheme for partial transmit sequence OFDM

In general, there has been a trade-off between performance of peak-to-average power ratio (PAPR) reduction and computational complexity in partial transmit sequence (PTS) orthogonal frequency division multiplexing (OFDM). In this paper, a novel subblock partition scheme (SPS) for PTS OFDM is proposed and analyzed. In this scheme, signals assigned randomly in partial subbands are duplicated and concatenated repetitively to generate each subblock. The proposed scheme, therefore, has a form of concatenation of pseudo-random and interleaved SPS. As results of simulations, the proposed scheme shows almost same PAPR reduction performance as compared to the conventional pseudo-random SPS which has been known to have the best performance. However, computational complexity can be reduced extensively. Hence, the proposed scheme may be considered to be more suitable than the conventional ones for application in high speed transmission systems such as digital terrestrial broadcasting.

Performance of STBC with turbo code in HARQ scheme for mobile communication systems

The performance of STBC (space time block codes) concatenated with turbo codes in an HARQ (hybrid automatic repeat request) scheme is analyzed. When two transmitter antennas are used, up to 5dB and 10dB gains are obtained in AWGN and Rayleigh fading channels, respectively, as compared to the conventional one antenna system. Gain in the fading channel is much larger than in the AWGN channel. Therefore, STBC with turbo codes may be a suitable HARQ scheme for future third generation mobile communication systems such as cdma2000 and W-CDMA.

An improved DC- and Nyquist-free error control line code

An improved DC- and Nyquist-free error control line code based on the (8,4) extended Hamming code is proposed and its performance is analyzed. To increase its code rate, two blocks of error control codes are used as a line code with simple pre-coding. The proposed code can be well suited for high speed communication links, where DC- and Nyquist-free pulse format, channel error control, and low-complexity encoder-decoder implementations are required. As results of performance analysis, the proposed code shows null points at DC and Nyquist frequency and low levels of complexity. In addition, the proposed code shows wider eyewidth due to its Nyquist-free property.<<ETX>>