# SDR Proof-of-Concept of Full-Duplex Jamming for Enhanced Physical Layer Security
## 5 Evaluation
### SCS-HK with Self-Interference Cancellation  
In this section we explore the combination of SI cancellation with the scrambled coding for secrecy scheme (SCS-HK) described in Section 2.1 to enhance the security advantage obtained from SI cancellation, as shown in previous sections. To perform this evaluation, the LMS filter is chosen and the fairest scenario is set. Figure 11: PLR and BER plots of Setup III (favorable for [PERSON]) when using LMS. Figure 10: PLR and BER plots of Setup II (favorable for [PERSON]) when using LMS. The SCS-HK scheme is a coding for secrecy mechanism that exploits the usage of scrambling with a hidden key and puncturing of that key prior to transmission to increase secrecy in communication. This technique grants reliability to [PERSON] and enhanced confusion to [PERSON], when [PERSON]'s channel is worse than [PERSON]'s [4; 29]. When combined with the jamming component of this work, the goal is to enhance the degradation of the channel between [PERSON] and [PERSON] caused by the jamming to further increase [PERSON]'s BER. For that, we will evaluate the impact of several puncturing patterns (i.e., number of bits punctured in the codeword) for selected values of jamming power (chosen according to the previous results for low PLR and BER). Specifically, we consider a range of \(0,20,44,65,85,100\) bits punctured, for jamming values of \(22,24,26,28\) dBm. Note that the case of 0 punctured bits corresponds to the case in which the additive scrambler is employed without erasing the key before transmission, and it is here considered for comparison. In addition, note also that, if [PERSON] doesn't jam [PERSON], both have the same SNR (as implied by Setup I) and thus, the SCS-HK technique does not provide any security advantages for [PERSON] against [PERSON]. As the SCS-HK affects only the payload's packet, we will base the analysis only on the BER metric. Figure 12 presents [PERSON] and [PERSON]'s BER results as function of the number of punctured bits and jamming power. Results show the clear impact of an increase in the SCS-HK's number of punctured bits in the decrease of the BER performance, particularly for [PERSON] given some values of jamming. The main goal is looking for the combinations where [PERSON]'s BER increases quicker than [PERSON]'s BER allowing us to have a combination where puncturing interference is significantly heavier on [PERSON] (because it is combined with jamming and in [PERSON] the jamming is canceled). The one situation in which increasing the number of puncturing bits produced no effect is when a high jamming power of 28 dBm is employed, which already causes a high BER for [PERSON]. Therefore, there is no interest of using the SCS-HK scheme with this level of jamming power, so it is excluded from further analysis. In the same way, when considering 22 dBm of jamming power, as this doesn't degrade [PERSON]'s channel considerably, the SCS-HK scheme not only affects her, but also impacts [PERSON] considerably. Thus, the SCS-HK scheme is not worth implementing in a transmission with this jamming power value in this scenario. Moreover, there are combinations with jamming \(>22\) dBm in which [PERSON] experiences a similar BER, while [PERSON] undergoes a much lower one. For example, for 22 dBm of jamming power and 100 bits punctured, [PERSON]'s BER is \(5.60\times 10^{-2}\) and [PERSON]'s BER is \(9.61\times 10^{-3}\), while with 24 dBm of jamming power and 44 bits punctured, [PERSON]'s BER is \(6.11\times 10^{-1}\) and [PERSON]'s BER is \(6.07\times 10^{-6}\), i.e., with  
Figure 12: [PERSON] and [PERSON]’s BER performance of SCS-HK combined with full-duplex (FD) jamming as function of the number of bits punctured and [PERSON]’s jamming power. [PERSON]’s results assumes that he employs the LMS technique on the cancellation of SI. relatively the same value of [PERSON]'s BER, [PERSON]'s BER is significantly lower. Therefore, this jamming/puncturing combination is also excluded from further analysis.