1.  Field
Exemplary embodiments relate to an electronic apparatus capable of avoiding wireless signal coexistence interference of a plurality of communication modules, and a controlling method thereof. 
2.  Description of the Related Art
While electronic devices such as set-top boxes (STBs) are becoming smaller in size, the number of wireless communication modules installed on one electronic device is increasing.  For example, a single STB may include a WiFi module, a ZigBee module, a Radio Frequency for Consumer Electronics (RF4CE) module, a Bluetooth (BT) module, a Bluetooth Low Energy (BLE) module, and the like.  In that case, interference may occur between signals of the respective wireless communication modules and therefore may adversely affect the communication quality of the STBs. 
In the related art, attempts have been made to solve the problem by a method of ensuring a sufficient distance between the wireless communication modules.  If a sufficient distance can be secured, even if a plurality of wireless communication modules using the same frequency band operate simultaneously, it is possible to avoid the influence of coexistence interference. 
However, since many small electronic devices have adopted Multiple Input Multiple Output (MIMO) antenna technology to provide wireless communication at a high speed and stability, it is difficult to solve the coexistence interference problem in the method of changing the shape and the arrangement position of the antenna as in the related art. 
For example, when an electronic device (e.g., set-top box) includes a WIFI module which is operated based on the MIMO antenna technology, along with a ZigBee module, a RF4CE module, and a Bluetooth module, communication signal interference may affect the entire electronic device because the output of the WIFI module is greater than the output of the ZigBee, RF4CE, and Bluetooth modules.  The set-top box may use the ZigBee, RF4CE, and Bluetooth modules to communicate with a remote controller.  When the transmission power level (Tx power level) of the WIFI module exceeds a recognizable maximum reception power level (Rx power level) of the ZigBee, RF4CE, and Bluetooth modules, the ZigBee, RF4CE, and Bluetooth modules may be in saturation state.  In such a case, the set-top box may not be able to recognize signals from the remote controller and the user cannot control the set-top box using the remote controller.