# Effects of Interference and Mitigation Using Notch Filter for the DVB-S2 Standard
The third part is the frame synchronization which allows the boundaries of packets to be detected and the data extraction for decoding [13]. The final part is the carrier frequency recovery that allows a smooth adjustment of the observed carrier frequency whose movement is caused by the Doppler effect and carrier frequency shift [14]. The CWI has an impact on all those sections, and they will be studied in detail to determine the exact effect on the communication performances. CWI has two important characteristics: power and center frequency. At first, it seems that the only important parameter is the power, but a smart jammer can adjust the center frequency and completely stop the receiver even with a low power interference. Therefore, this research not only tries to clarify the degree of negative impacts based on the input power of interference, but also to examine the sensitivity of each different block's performance based on the center frequency value and, potentially, avoid a dangerous low power smart attack [2]. In order to remove the CWI and protect the system against the narrowband attacks, this research focuses on the use of a novel implementation of an adaptive notch filter [15]. Quality of Service (QoS) must be preserved in different situations. However, for any interference mitigation, the removal of the interference cannot be perfect, which means that the mitigation process will affect the useful signal. First, the effect of a notch filter on the signal without any interference is studied to discover how much information is lost from the original signal based on the bandwidth of a notch filter Afterwards, the impact of the notch filter on a signal with CWI is investigated. These results will be compared for different r values which is a parameter that controls the notch filter bandwidth. QoS enhancement and interference power reduction after filtering are carefully measured in terms of three parameters: Signal to Noise Ratio (SNR), Jamming to Signal Ratio (JSR) and Bit Error Rate (BER). This paper investigates the effect of CWI on each section of a DVB-S2 [10] receiver and its removal with an adaptive notch filter. The DVB-S2 standard was released in 2005 and then became one of the most widely used video broadcasting standards. In February 2014, it was followed by the DVB-S2X, which allowed a faster communication protocol than its predecessor. Nowadays, DVB-S2 is still widely used and faces some problems with the increasing amount of interferences. For this study, the DVB-S2 standard was used because of its outstanding structure to handle the worst channel situation. The standard DVB-S2X, although more recent, is founded on the same core components as the original DVB-S2 standard. That means that it is sharing the same digital signal processing blocks as DVB-S2. This standard also represents relatively well the reception structure of most other telecommunication standards. All selected algorithms are those that are highly recommended in the user manual and structure of the DVB-S2 standard and based on those algorithms, the DVB-S2 standard can achieve performance close to the Shannon-Hartley limit [10].