Power allocation scheme for OCDMA NG-PON with proportional–integral–derivative algorithms

Distributed power control algorithms (DPCAs) based on the Foschini/Miljanic (FM) and Verhulst (V) models and a proportional–integral–derivative (PID) algorithm have been investigated in this work for next-generation passive optical networks (NG-PONs). The DPCAs of FM and V that are represented by the classical control theory as an integral control present limitations in the accuracy of signal-to-noise-plus-interference ratio (SNIR) estimates in weak-signal environments. Furthermore, in this work the development of DPCA-PID-FM and DPCA-PID-V based on PID schemes originated as DPCA-FM and DPCA-V, respectively, has been conducted to overcome the SNIR estimation limitation. The main results have shown that DPCA-FM reaches convergence with a lower number of iterations than DPCA-V for situations of a good SNIR. However, under weak-signal scenarios, DPCA-V exhibits a smaller discrepancy from the optimum power vector solution and better convergence than DPCA-FM. Also, the proportional and differential actions taken in DPCA-V to originate DPCA-PID-V do not present a noticeable impact on the tendency and the velocity of the convergence compared with DPCA-V. On the other hand, DPCA-PID-FM changes the trend in convergence from DPCA-FM. Finally, the increase in channel error estimation causes an error of convergence for all DPCAs studied in this work. The main advantage of DPCAs based on PID is the possibility of utilizing adaptive tuning procedures to tune the PID gains.