This paper is on the design of an adaptive sending rate for frequency regulation of a smart microgrid. The frequency controller itself is designed using an optimal LQR (Linear Quadratic Regulator) approach whose parameters are obtained using Particle Swarm Optimization (PSO). The utilized isolated smart microgrid comprises different Distributed Generation (DG) units and Renewable Energy Sources (RESs). Implementation of the optimal LQR controller requires a communication network. The key issue in this Networked Control System (NCS) is the transmission of measured data from the multiple sensing agents to the controller. Usually the data is sent in constant intervals which raises energy issues and channel capacity and requires bigger sending rate that will cause more error in the frequency response. The paper proposes different adaptive approaches for determining an adequate sending rate. Simulation results show the effectiveness of the proposed approaches as compared to conventional methods.