# An Adaptive 24 GHz PSO-Based Optimized VCO in Next-Generation Wireless Sensor Networks
###### Abstract  
Wireless sensor networks (WSNs) for self-driving vehicles are growing rapidly, requiring high-performance radar systems with strong communication abilities. The key component of these systems is the voltage-controlled oscillator (VCO), which performs at 24 GHz with low phase noise, low power consumption, and a wide range of tuning. In this paper, the adaptive particle swarm optimization (PSO) algorithm incorporates adaptive scaling to speed up the optimization process. The new adaptive PSO minimizes the number of calculations required for complex engineering problems where rapid optimization is crucial and finding the best solution quickly is important. In order to test the adaptive PSO, benchmark functions are used. When applied to the proposed VCO circuit design, it facilitates more efficient adjustment of component values and improved performance, resulting in faster optimization. This optimized VCO achieves low phase noise of \(-120\)\(\mathrm{d}\mathrm{B}\mathrm{c}\mathrm{/}\mathrm{H}\mathrm{z}\) with a 1 MHz offset and a tuning range of 21.2%, operates at just 0.9 V, and consumes just 1.35 mW of power. A comparison of adaptive PSOs with traditional PSO methods shows that they improve the performance of the VCO, making them a promising choice for future automotive radar systems. wireless communication; sensor networks; optimization; PSO; VCO; phase noise [PERSON]  
[PERSON], [PERSON], K.  
Developing transceiver (TRX) circuits for this frequency range presents several challenges, including the need to design circuits that consume very little power while maintaining high integration and producing very low phase noise in the process. The voltage-controlled oscillator (VCO), one of the most important parts of a TRX, needs to fulfill these exacting performance standards. A VCO with three critical characteristics, i.e., a large tuning range, low power consumption, and minimal phase noise, is necessitated by the demanding requirements of a 5G TRX system. With CMOS technology, VCOs can be difficult to design due to their limited transconductance, and this difficulty is compounded when designing low-power circuits operating at high frequencies, such as in the 24 GHz to 86 GHz range that is required for 5G. The challenges of circuit design have been addressed by utilizing a variety of circuit design techniques [5]. For instance, different circuit topologies and the use of a current-reuse configuration are discussed regarding the receiver design in [6] and the transceiver design in [7]. While high data transfer rates are offered by traditional VCO designs using cascaded transistor structures, high power consumption is often suffered from by them. To lessen this problem, different RF circuits, such as amplifiers [8] and VCOs [9; 10], have had the current-reuse configuration applied. The block diagram of the optimization algorithm integrated with the RF circuit is shown in Figure 2.  
Figure 1: Overview of an automotive radar in WSN. However, the use of N/PMOS cross-coupled transistors in current-reuse VCOs results in phase noise degradation and transconductance mismatch because of the phase noise degradation and transconductance mismatch that can occur. To mitigate these issues [11], the resistive degeneration approach has been used to balance transconductance and enhance the VCO's overall performance characteristics. Optimization algorithms are broadly used in various scientific and engineering disciplines to improve performance and fine-tune circuit designs. The complexity of designing an optimal RF system is due to the unique requirements of each system. For example, high efficiency and power are required by radar applications, whereas high linearity and wide bandwidth are demanded by base station applications [12]. The performance of a VCO is determined by its component values and transistor model, but in order to improve its characteristics, additional optimizations are often required. Researchers have applied several optimization techniques to RF circuit design.