Adaptive composite bandwidth and automatic gain control receiver for 6G wireless optical communication

Abstract

The advent of 6G communication promises a transformative leap in wireless connectivity, ushering in an era of unprecedented data rates, ultra-low latency, and pervasive connectivity. To harness the full potential of 6G networks, it is imperative to address the unique challenges posed by evolving communication environments. In this context, we present a novel framework that integrates Adaptive Composite Bandwidth and Automatic Gain Control techniques into the 6G communication paradigm. Optical wireless receivers experience large input current difference due to the large transmitted power, noise from ambient light and the varying efficiencies of different photodiode receivers. With its large dynamic range of μA to mA, transimpedance amplifiers are suitable to handle photodiode efficiency with a large dynamic range. The receiver design proposed in this article incorporates two characteristic parameter adjustments, namely, bandwidth and automatic gain. By adjusting the bandwidth the signal-to-noise ratio of the incoming signal is automatically controlled. By controlling the bandwidth, the unwanted noise is reduced and amplifier output is liable to low noise and enhances the dynamic range without extra filtering. The automatic gain control adapts its gain based on slight change in the input signal at the receiver front-end. This optimization technique ensures low photo-detection and amplification noise to achieve better quality of service. The results indicate that the bootstrap transimpedance amplifier gain is around 53.3 dB and frequency cut-off at 109.7 MHz. Thus, when gain control capacitance is varied between 50 pF to 1 nF, the bandwidth adjustment falls in the range 7.5–104.1 MHz, and the amplifier’s second stage gain becomes 10.4 dB. The overall gain of the proposed configuration with automatic gain control integrated into the transimpedance amplifier increases up to 31.1 dB, while the bandwidth increases from 9.4 to 60.7 MHz. Consequently, the gain bandwidth product is optimized from 10.4 to 31.1 dB. The main contribution of this work is optimizing the product by selecting a capacitance value within the given range that maximizes the gain-bandwidth product. This optimization paradigm is predicated on identifying a capacitance value that minimizes the gain-bandwidth product, thereby effectuating effective noise mitigation. This proposed framework embodies a significant contribution to the domain of 6G communications, heralding a new epoch in the optimization of wireless connectivity through the strategic integration of adaptive bandwidth and automatic gain control mechanism.