In this paper, we address the problem of connectivity maintenance for a group of robots connected via wireless communication. We consider fading in the wireless channel between agents, where the exchange of information is possible at permissible distances. A distributed controller is designed to maintain the global connectivity of the network communication graph. On the other hand, obtaining the best communication quality between agents is the definition of good network connectivity. Therefore, the Laplacian matrix is defined as a weighted graph according to the communication parameters. Initially, the controller uses the supergradient algorithm to remake the network Laplacian matrix for having a greater second eigenvalue. While each agent in the network only has access to the neighbor\\\\\\\'s information. The control algorithm uses a multi-agent estimator to find the eigenvector corresponding to the second small eigenvalue. The formation problem has been considered in the second step after the reference topology has been obtained. Because of the nonlinear dynamics of the agents, the sliding mode controller has been used for this purpose. This robust controller could be a suitable choice due to the modeling and sensor measurement uncertainties. Finally, an example of multi-agent robots is provided to evaluate the algorithm.

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