사용자간 동기오차와 증폭기의 비선형 왜곡을 동시에 고려한 두 상향링크 OFDMA 기법의 채널용량 비교 분석

Abstract

In this paper, we investigate channel capacity of two kinds of uplink OFDMA (Orthogonal Frequency Division Multiple Access) schemes, i.e. ZCZ (Zero Correlation Zone) code time-spread OFDMA and sparse SC-FDMA 논문 14-39A-05-07 The Journal of Korea Information and Communications Society '14-05 Vol.39A No.05 http://dx.doi.org/10.7840/kics.2014.39A.5.258 258 ※ 본 연구는 2012년도 정부(교육과학기술부)의 재원으로 한국연구재단의 지원을 받아 수행되었습니다.(2012R1A1A4A01015628) First Author : Yeungnam University Dept. of Information Communications Engineering, jinh37@ynu.ac.kr, 학생회원 ° Corresponding Author : Yeungnam University Dept. of Information Communications Engineering, gonew@ynu.ac.kr, 종신회원 * 영남대학교 정보통신공학과 무선통신실험실 , hishope21@ynu.ac.kr, 정회원 논문번호:KICS2014-03-077, Received March 5, 2014; Revised April 30, 2014; Accepted April 30, 2014 논문 / 사용자간 동기오차와 증폭기의 비선형 왜곡을 동시에 고려한 두 상향링크 OFDMA 기법의 채널용량 비교 분석 259 (Single Carrier Frequency Division Mmultiple Access) robust to access timing offset (TO) among multiple users. In order to reflect the practical condition, we consider not only access TO among multiple users but also peak to average power ratio (PAPR) which is one of hot issues of uplink OFDMA. In the case with access TO among multiple users, the amplified signal of users by power control might affect a severe interference to signals of other users. Meanwhile, amplified signal by considering distance between user and base station might be distorted due to the limit of amplifier and thus the performance might degrade. In order to achieve the maximum channel capacity, we investigate the combinations of transmit power so called ASF (adaptive scaling factor) by numerical simulations. We check that the channel capacity of the case with ASF increases compared to the case with considering only distance i.e. ASF=1. From the simulation results, In the case of high signal to noise ratio (SNR), ZCZ code time-spread OFDMA achieves higher channel capacity compared to sparse block SC-FDMA. On the other hand, in the case of low SNR, the sparse block SC-FDMA achieves better performance compared to ZCZ time-spread OFDMA.