###### Abstract  
By increasing the demand for radio frequency (RF) and access of hackers and spoofers to low price hardware and software defined radios (SDR), radio frequency interference (RFI) became a more frequent and serious problem. In order to increase the security of satellite communication (Satcom) and guarantee the quality of service (QoS) of end users, it is crucial to detect the RFI in the desired bandwidth and protect the receiver with a proper mitigation mechanism. Digital narrowband signals are so sensitive into the interference and because of their special power spectrum shape, it is hard to detect and eliminate the RFI from their bandwidth. Thus, a proper detector requires a high precision and smooth estimation of input signal power spectral density (PSD). By utilizing the presented power spectrum by the simplified Welch method, this article proposes a solid and effective algorithm that can find all necessary interference parameters in the frequency domain while targeting practical implantation for the embedded system with minimum complexity. The proposed detector can detect several multi narrowband interferences and estimate their center frequency, bandwidth, power, start, and end of each interference individually. To remove multiple interferences, a chain of several infinite impulse response (IIR) notch filters with multiplexers is proposed. To minimize damage to the original signal, the bandwidth of each notch is adjusted in a way that maximizes the received signal to noise ratio (SNR) by the receiver. Multiple carrier wave interferences (MCWI) is utilized as a jamming attack to the Digital Video Broadcasting-Satellite-Second Generation (DVB-S2) receiver and performance of a new detector and mitigation system is investigated and validated in both simulation and practical tests. Based on the obtained results, the proposed detector can detect a weak power interference down to \(-25\) dB and track a hopping frequency interference with center frequency variation speed up to \(3\) kHz. Bit error ratio (BER) performance shows \(3\) dB improvement by utilizing new adaptive mitigation scenario compared to non-adaptive one. Finally, the protected DVB-S2 can receive the data with SNR close to the normal situation while it is under the attack of the MCWI jammer. multiple carrier wave interference; simplified Welch algorithm; threshold; power spectral density; digital receiver; narrowband communication; digital receiver; notch filter; jamming to signal ratio; Satcom; notch filter; interference mitigation; detector; DVB-S2 +
Footnote †: journal: Applied Sciences  
face serious degradation in their performance or a complete cut off in data transceiving. A famous example of this modern wireless problem, is interference from Inmarsat that can completely stop Iridium uplink/downlink communications [3]. In many cases, the target of hackers and military forces is to prevent or corrupt RF communications. Jamming, is the intentional type of RFI transmitted in different wireless network layers [4,5]. Benefiting from recent advances in low-cost hardware and software-defined radios (SDR), jammers have more opportunity to deploy smarter jamming attacks to corrupt radio communication networks [6]. An inexpensive device can create a large variety of jamming signals; however, the mitigation process for the receiver is much harder [7]. On many applications, like navigation, partial or complete signal loss can have disastrous consequences thus, it is crucial to detect the RFI in desired bandwidth and protect the receiver with a proper mitigation mechanism. Satcom channels suffer from several destructive effects like Doppler [8] and variable time delay [9]. In a typical digital receiver, a chain of several blocks is employed to compensate the channel effects and fulfill the demodulation duty. The complete data reception depends on efficient performance of all of the blocks and if one block cannot fulfill its duty, all the packet data will be lost.