Code division multiple access (CDMA) is one of the promising medium access control (MAC) schemes for underwater acoustic sensor networks because of its robustness against frequency-selective fading and high frequency-reuse efficiency. As a way of performance evaluation, sea or lake experiment has been employed along with computer simulation.. In this study, we design the underwater CDMA forward-link transceiver and evaluate the feasibility aginst harsh underwater acoustic channel in water-tank first. Then, based on the water-tank experiment results, we improved the transceiver and showed the improvements in a lake experiment. A pseudo random noise code acquisition process is added for phase error correction before decoding the user data by means of a Walsh code in the receiver. Interleaving and convolutional channel coding scheme are also used for performance improvement. Experimental results show that the multiplexed data is recovered by means of demultiplexing at receivers with error-free in case of two users while with less than 15% bit error rate in case of three and four users. 논문 14-39C-02-10 한국통신학회논문지(J-KICS) '14-02 Vol.39C No.02 http://dx.doi.org/10.7840/kics.2014.39C.2.199 199 ※본 연구는 방위사업청과 국방과학연구소의 지원으로 수행되었으며, 이에 대해 깊이 감사를 드립니다. (계약번호 UD130007DD) First Author : 경북대학교 IT대학 전자공학부 이동통신연구실, bmseo@ee.knu.ac.kr, 학생회원 ° Corresponding Author : 경북대학교 IT대학 전자공학부 이동통신연구실, hscho@ee.knu.ac.kr, 종신회원 * 국방과학연구소, sk142298@add.re.kr 논문번호:KICS2013-12-533, 접수일자:2013년 12월 12일, 심사일자:2014년 1월 20일, 최종논문접수일자:2014년 2월 3일 한국통신학회논문지(J-KICS) '14-02 Vol.39C No.02