A study on spreading factor selection criteria for code division multiple access method on the underwater communications

Ye-gwon Hong; Ji-won Jung; Jun-ho Kim; Byoung-sun Ahn

doi:10.7776/ASK.2025.44.4.374

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2025 Vol.44, Issue 4 Preview Page Next Page

Research Article

A study on spreading factor selection criteria for code division multiple access method on the underwater communications 수중 통신 환경에서 코드분할 다중 접속 방식을 위한 확산 요소 선택 기준 연구

31 July 2025. pp. 374-383

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Abstract

In time variant underwater environments, application of various adaptive methods are essential in order to enhance performance and transmission rate simultaneously. In Code Division Multiple Access (CDMA) method, which overcome selective frequence fading induced by delay spreading, its performance and information rate are different according to Spreading Factor (SF) which denotes amount of bandwidth expansion. Therefore, we propose adaptive SF mode transmission method based on Channel Quality Indicator (CQI) criteria for selecting optimal SF. Using Pilot symbols known as transceiver, estimated Pilot Signal to Noise Ratio (PSNR) and Pilot-Bit Error Rate (P-BER) are employed as COI criteria, and we establish an optimal CQI criteria by varying underwater channel conditions. It was confirmed through simulations that successive transmission rate of the proposed adaptive SF mode improved about 15 % ~ 45 % compared to that of conventional fixed SF mode.

Keywords

Adaptive method

Spreading Factor (SF)

Channel Quality Indicator (CQI)

Pilot Signal to Noise Ratio (PSNR)

Pilot Bit Error Rate (P-BER)

시변하는 수중 환경에서 다중 경로로 인한 지연 확산을 극복하고 성능과 정보 전송률을 동시에 향상 시키기 위한 다양한 적응적 기법 적용이 매우 필수적이다. 지연 확산으로 인한 선택적 주파수 페이딩을 극복할 수 있는 코드분할 다중접속(Code Division Multiple Access, CDMA) 방식은 정보 비트를 확산시키는 Spreading Factor(SF)의 길이에 따라 성능과 정보 전송률이 다르다. 본 논문에서는 수중 채널 환경에 따라 CDMA 전송 기법에서 최적의 SF를 선택할 수 있는 기준인 Channel Quality Indicator(CQI) 기반의 적응형 SF 모드 전송 기법을 제안한다. 본 논문에서 적용된 CQI는 송수신자가 서로 알고 있는 파일럿 정보를 이용하여 Pilot Signal to Noise Ratio(PSNR)과 Pilot Bit Error Rate(P-BER) 추정치를 이용하였으며, 이의 기준을 설정하여 시변 수중 채널에 적응적으로 SF를 변화하였다. 제안한 방법은 고정된 SF를 갖는 기존의 방법에 비해 약 15 % ~ 45 %의 정보 전송률 향상을 나타내는 것을 모의 실험을 통해 확인하였다.

키워드

적응형 기법

확산 인수

채널 품질 지시자

파일럿 신호대 잡음비

파일럿 비트 오류율

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Information

Publisher :The Acoustical Society of Korea
Publisher(Ko) :한국음향학회
Journal Title :The Journal of the Acoustical Society of Korea
Journal Title(Ko) :한국음향학회지
Volume : 44
No :4
Pages :374-383
Received Date : 2025-05-22
Accepted Date : 2025-07-09
DOI :https://doi.org/10.7776/ASK.2025.44.4.374

The Journal of the Acoustical Society of KoreaISSN:1225-4428(Print) 2287-3775(Online)한국음향학회

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