In this work, a full-duplex hybrid visible light communication (VLC) and optical code division multiple access (OCDMA) for varied transmission range and data rate for different codes and light emitting diodes (LEDs) is analyzed respectively. The simulation results show that out of all codes random diagonal (RD) code offers high VLC transmission range of 70m in uplink and 55m in downlink at 10Gbps information rate than multi-diagonal as well as zero cross correlation codes. Also, high data rate of 90Gbps in uplink and 75Gbps in downlink can be obtained by employing red LED and RD code in the designed system over 10m VLC range. In addition, the comparison of the proposed work with other previous is presented to show its superiority. Optical code division multiple access (OCDMA), internet of things (IoT), visible light Proceedings of International Symposium on Securing Next-Generation Systems using Future Artificial Intelligence Technologies
communication (VLC), fifth generation (5G)
The requirement for data intake of a mobile user improves continually. However in 2016, the information traffic was 7EB/month, the estimated information traffic for 21st centaury till now is supposed to be approximately 50EB. To manage such huge amount of data, latest and more effective techniques for data transmission must be evolved. The solution is to enhance a efficiency of spectral in recently downtrodden radio frequency bands. While even radio band is not suitable to cope with a spectrum crunch phenomenon. For this, visible light communication (VLC) permits an extended unlicensed spectrum bands which provides a high-speed transmission of data [1]. Also, VLC technology combines and complements with 5G and beyond this to meet the recent and nextgeneration high transmission rate as well as capacity utilization. Short distance communication within a campus, video monitoring and surveillance, disaster recovery, back-haul system etc. is some of the potential applications of VLC technology [2].
VLC has been regarded as a substitute to communicate huge sensing data generated by widespread internet of things (IoT) sensor nodes. These IoT smart sensors have capability to respond in the real world events in an rapid, automatic as well as enlightened way not only reveals new possibilities for handling critical or complex situations, but too allows a broad range of technologies operation to be optimized [3]. Various research work papers [4–6] focused on a VLC scenario.
Further, optical code division multiple access (OCDMA) is emerging as a promising solution that can offer quality of service in physical layer. OCDMA schemes are getting considerable attention due to its ability to behave asynchronously, improved capacity as well as privacy. Several OCDMA codes have been used to handle multimedia applications like random diagonal (RD) , zero cross correlation (ZCC), multi-diagonal (MD) etc. to cope with permitting large number of consumers to broadcasting high transmission rates adapted to various multimedia transmission [7]. Table 1 indicates the existing methodologies used in the previous work along with their pros as well as cons.
2023 Copyright for this paper by its authors.
Ref. Year System Pros Cons [8] 2016 WDM-VLC 4.5m+20km 10Gbps [9] 2020 WDM-VLC 2.3Tbps 1.5m [5] 2021 wired/VLC Range=10m+50km Data rate=10/10Gbps [10] 2022 wavelength 50Gbps 12m division multiplexing (WDM)/VLC
Previous recent work presents that, till now researchers have more focus on VLC system, but there is less work except [5], has been done on hybrid VLC-OCDMA system for IoT applications.
Thus in this paper a full-duplex hybrid VLC-OCDMA system using different OCDMA code on the basics of 5G for IoT applications has been reported. The novelty behind this work is to secure the IoT based VLC-OCDMA system using different OCDMA codes. It also enhances the transmission distance as well as data rate for various future based applications.
Main contributions of the proposed work: • Design a full-duplex hybrid VLC-OCDMA system. •
Compare the designed system for different OCDMA codes like multi diagonal (MD), random diagonal (RD) and zero cross correlation (ZCC) codes.
• Identify the system performance for varied VLC link as well as transmission rate.
The work is organized as: Section 2 presents the proposed design of hybrid VLC-OCDMA system. Section 3 depicts the results and discussion. Lastly, conclusion is dawn in Section 4.
The proposed hybrid VLC-OCDMA system is presented in Figure 1.
The proposed block diagram presents the full-duplex hybrid VLC-OCDMA system using RD, MD and ZCC codes for four users. It includes four downstream (DN) coded transmitters (TXs) and upstream (UP) coded TXs. For downlink transmission, each TX section consists of a series of pseudo random bit sequence generator with non return to zero data format to be modulated with incoming laser input signals via mach zehnder modulator. The code construction for three users RD, MD and ZCC code using three LEDs (red=640nm, white=625nm+514nm+450nm and violet=400nm) is reported below in Table 2.
Table 2 Code designs
The proposed hybrid VLC-OCDMA system performance is measured under the influence of external interferences and noise in OptiSystem. Downstream Upstream Upstream
Figure 2(a) presents the BER performance of full-duplex VLC-OCDMA system employing RD, MD and ZCC codes for varied VLC range in both DN and UP transmission at 10/10Gbps data rate. It is seen that with increase transmission range, the performance of system degrades for various codes in both DN and UP directions. Also, RD code performs best compared to other codes in UP transmission as compared to DN transmission. The maximum achieved VLC range for RD, MD and ZCC code is 70, 60 and 50m in UP transmission, at 10-3 BER threshold. Also, the faithful VLC range for RD, MD and ZCC code is 55, 45 and 40m in DN transmission.
Figure 2(b) depicts the BER performance of full-duplex VLC-OCDMA system employing RD code for varied data rate in both DN and UP transmission over 10m range for different LEDs. It is noted that with increase transmission rate, the performance of system diminishes for various LEDs in both DN and UP directions. Also, out of all codes, red LED shows best performance than white and violet LEDs in UP transmission as compared to DN. The highest obtained transmission rate for red, white and violet LED is 90, 80 and 70Gbps respectively, at BER threshold in UP transmission. Moreover, in DN transmission, the maximum transmission rate for red, white and violet LED is 75, 65 and 60Gbps respectively. (d) (e) (f) Figure 3: Eye patterns of the hybrid VLC-OCDMA system using RD code over (a)70m, (b)60m and (c)50m VLC range for UP; (d)70m, (e)60m and (f)50m VLC range for DN transmission (d) (e) (f) Figure 4: Eye patterns of the hybrid VLC-OCDMA system using RD code over (a)20Gbps, (b)60Gbps and (c)90Gbps VLC range for UP; (d)20Gbps, (e)60Gbps and (f)90Gbps VLC range for DN transmission (b) Figure 5: Measured spectra of the hybrid VLC-OCDMA system using RD code at (a) Tx and (b)Rx over 10m range at 10Gbps rate
Figure 5(a) as well as 5(b) report that the measured spectra of the proposed system at transmitter as well as receiver side.
Tables 4 reports that for the proposed work faithful VLC range is 70m at symmetric 90Gbps data rate which is maximum than other existing works. However, this work has some limitations like external noise, large codes length, limited range and design complexity. In future more work need to be done on VLC-OCDMA system using LASER and optimum code to support the large no. of customers.
A full-duplex hybrid VLC-OCDMA using three different codes and three LEDs is presented. It is concluded that RD code presents finest performance with VLC range of 70m in uplink and 55m uplink direction than MD as well as ZCC code at BER threshold at 10Gbps. Also, the transmission rate can be extended upto 90Gbps and 75Gbps in uplink and downlink directions respectively, using RD code for red LED. Besides this, the proposed work shows better work than other previous works.
Z. Becvar, R.G. Cheng, M. Charvat, P. Mach, Mobility management for D2D communication