As the number of internet users in Indonesia continues to grow, concerns arise over the saturation of radio wave transmission technologies. In response, the National Research and Innovation Agency (BRIN) delves into visible light communication (VLC) systems to meet the escalating demands for internet access.
Rahmayati, a researcher from the Electronics and Optics Network Research Group at the BRIN Electronics Research Center, elucidates that the current internet access relies heavily on radio frequency (RF) transmission technologies such as Bluetooth, Zigbee, LoRaWAN, WiFi, NB-IoT, 4G, and others.
"Considering the electromagnetic spectrum, RF operates within a bandwidth of 40 GHz, which is nearly saturated. Hence, VLC research emerges, leveraging the visible light spectrum for communication," Rahmayati stated in a press release on Thursday (March 28, 2024). with galaxy fit 3 specs revealed.
Researchers identify an opportunity in higher frequencies, specifically visible light, which boasts a bandwidth ten thousand times that of RF and remains untapped for communication purposes.
"Existing studies indicate that relying solely on radio frequencies is insufficient and may lead to a spectrum crisis. Therefore, a shift towards VLC becomes imperative as the user base expands," Rahmayati added.
Compared to radio frequencies, VLC offers several advantages, including unlicensed spectrum utilization ranging from 430 THz to 790 THz, which is currently used solely for illumination rather than communication. Additionally, VLC supports 5G-6G networks and excels in indoor accessibility.
Moreover, VLC ensures heightened security, cannot penetrate solid walls, offers large bandwidth, and is cost-effective. By harnessing light sources such as LEDs and integrating communication functions, VLC enhances the value of LEDs while minimizing communication costs.
"VLC is devoid of electromagnetic interference, making it suitable for electromagnetically sensitive areas such as hospitals, petrochemical plants, and aircraft," Rahmayati emphasized.
Further elaborating, Rahmayati highlights two key components underpinning VLC: lighting technology and modulation techniques. Among modulation techniques, multi-carrier modulation (MCM) based on orthogonal frequency division multiplexing (OFDM) emerges as particularly promising.
Among various modulation techniques, Rahmayati references the research on layered asymmetrically clipped optical-orthogonal frequency-division multiplexing (LACO-OFDM). While existing LACO-OFDM research primarily focuses on mathematical formulas, Rahmayati's research proposes a more comprehensive evaluation encompassing performance parameters, efficiency, verification (simulation, DSP to DSP, circuitry), and cost-effectiveness.
Conclusively, after scrutinizing various optical OFDM variants for VLC, LACO-OFDM emerges as the most feasible for implementation based on energy efficiency, spectral efficiency, peak-to-average power ratio (PAPR), and computational complexity comparisons.
Rahmayati reveals the design of transmitters and receivers for establishing point-to-point visible light communication systems. Laboratory-scale transmission tests over a one-meter distance yield a bandwidth of 3 MHz for the transmitter and 2.5 MHz for the receiver.
Furthermore, FPGA implementation of DCO-OFDM and ACO-OFDM demonstrates minimal resource utilization (eight percent of FPGA resources) and low power consumption (0.081 W for DCO-OFDM and 0.082 W for ACO-OFDM).
In addition, LACO-OFDM, utilizing a fixed-size IFFT/FFT block combined with subcarrier mapping, consists of three layers, 16 subcarrier IFFT/FFT points, and QAM modulation on each subcarrier.
Simulation results indicate that the layered structure of LACO-OFDM achieves spectral efficiency twice that of ACO-OFDM. The design of LACO-OFDM based on Intellectual Property (IP) Core for a 4-layer structure, 32 subcarriers, 32-point IFFT/FFT, and 16-QAM modulation enables component reusability across the entire system.
In summary, BRIN's exploration of VLC for internet access in Indonesia promises enhanced efficiency, security, and affordability, marking a significant advancement in the nation's communication infrastructure.
