Optical Code Division Multiple Access Codes comparison in free space optics and optical fiber transmission medium

This study developed a bipolar optical code division multiple access (Bi-OCDMA) technique based on spectral amplitude coding for the formation and transmission of optical-polarized and coded signals over wireless optical channels. Compared with conventional Bi-OCDMA schemes, the proposed free-space optics communication system that uses a dual electro-optical modulator design improves the transmission rate. In theory, multiple access interference can be removed by using correlation subtraction schemes. The experiment results revealed that the proposed system can be employed to accurately extract codewords from an M-sequence and subsequently reconstruct the desired original data. Moreover, the proposed architecture can be implemented easily in simple and cost-effective designs and may be beneficial for broadening the use of Bi-OCDMA schemes in wireless optical communications.

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Performance comparison of code division multiple access and orthogonal frequency division multiplexing over turbulent effected free space optics link under the impact of advance coding formats

Journal of Optical Communications ◽

10.1515/joc-2019-0169 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Heena Arora ◽

Vishal Sharma

Keyword(s):

Free Space ◽

Code Division Multiple Access ◽

Orthogonal Frequency Division Multiplexing ◽

Multiple Access ◽

Data Rate ◽

Free Space Optics ◽

Frequency Division Multiplexing ◽

Frequency Division ◽

Space Optics ◽

Code Division Multiple

Abstract Free space optics (FSO) systems have gained considerable attention because of their numerous features and services. It has evolved into a promising technology for high data rate transmission in wireless communication systems. However, there are some atmospheric effects which inhibit its performance. In this paper, performance of code division multiple access–free space optics (CDMA–FSO) by combining multidiagonal (MD) codes and orthogonal frequency division multiplexing–free space optics (OFDM-FSO) systems over using advance line coding formats under the sway of turbulence conditions are investigated and compared. A comparative study has shown that CDMA–FSO offers better SNR with both CSRZ and AMI coding format under diverse conditions at data rate 15 and 20 Gbps.

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Hybrid Analog/Digital Modulations Using Polarization Multiplexing OCDMA Scheme in Free Space Optics

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.764-765.511 ◽

2015 ◽

Vol 764-765 ◽

pp. 511-514

Author(s):

Chih Ta Yen ◽

Chia Yu Liu

Keyword(s):

Free Space ◽

Orthogonal Frequency Division Multiplexing ◽

Multiple Access ◽

High Speed ◽

Base Station ◽

Free Space Optics ◽

Detection Scheme ◽

Space Optics ◽

Polarization Multiplexing ◽

Code Division Multiple

With the development of the Internet, how to provide a high-speed and high-security comprehensive network has become urgent issue. In this project, we propose hybrid analog/digital transmissions format scheme which integrated optical code-division multiple-access (OCDMA) and polarization multiplexing technique in free space optics (FSO) transmission. Orthogonal frequency division multiplexing (OFDM) transmits as the analog format and (on-off keying) OOK transmits as digital format in the study, respectively. In the proposed hybrid OCDMA system, it has high-speed transmission, signal security and low cost...etc. we adopt quasi-orthogonal Walsh-Hadamard codes (WHC) that with fixed cross correlation value as the codeword for each base station. With the property, the multiple access interference (MAI) can be efficiently eliminated by using the balanced detection scheme at the receive end. The constellation and eye diagrams show that both OFDM signal as analog signal and OOK modulation as digital signal in the proposed hybrid OCDMA system perform good performance in FSO transmission.

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A Multiple Fiber Grating Sensor System Using Code Division Multiple Access

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.765-767.2444 ◽

2013 ◽

Vol 765-767 ◽

pp. 2444-2447 ◽

Cited By ~ 1

Author(s):

Wei Li ◽

Yong Jia Zhang ◽

Hong Qiao Wen

Keyword(s):

Optical Fiber ◽

Fiber Bragg Grating ◽

Code Division Multiple Access ◽

Multiple Access ◽

Simulation Experiment ◽

Fiber Grating ◽

Sensing System ◽

Fiber Grating Sensor ◽

Fbg Sensors ◽

Code Division Multiple

In order to increase the multiplying density of Fiber Bragg Grating (FBG) sensors, a novel FBG Sensing System based on CDMA technology has been developed. Simulation experiment indicates the CDMA technology combine with optical fiber grating sensing system together successfully. Furthermore, the system can distinguishes the FBG and enhance the FBG network band utilization.

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