Disclosed are a server system for performing communication over a wireless network and a communication method thereof. The server system comprises at least one client device and a server device for performing a state monitoring operation or a control operation for the client device over the wireless network. When a data packet is sent, the server device begins to send a following packet by variably applying a transmission rate according to a network transmission state when a leading packet has been completely transmitted. Because a transmission rate can be set appropriately to the network state, the number of unnecessary retransmissions can be reduced. Therefore, transmission delay can be avoided and stable and rapid wireless communication can be achieved.