In Wireless Robotic Networks (WRNs), robots interact with each other to fulfill complex tasks such as target tracking, area coverage or environment monitoring. When designing the interactive controller with a more realistic consideration, connectivity needs to be maintained instead of simply assumed. In this paper, we give an introduction on how to maintain the connectivity of a communication graph which corresponds to a WRN. Due to the limited communication range of robots, proximity-limited communication models are used for the co-operative control problem and the connectivity maintenance problem in WRNs. Therefore, we review two kinds of proximity-limited communication models in this paper: the disk-based communication model and the hysteresis-based communication model. In addition, we present some network performance optimization work that based on communication metrics of Bit Error Rate (BER) and Signal to Interference plus Noise Ratio (SINR). Finally, we propose a new framework that involves the connectivity control and the network performance optimization, and potential solutions are discussed accordingly.