# On Vulnerability of Selected IoT Systems to Radio Jamming--A Proposal of Deployment Practices
## 4 Related Works  
Several approaches to the problem of jamming in IoT networks have been identified in the available literature. For instance, game theory has been applied in [4] to the jamming problem in OFDM-based (Orthogonal Frequency Division Multiplexing) IoT systems by smartly distributing power among the subcarriers; this is an approach suitable for cellular IoT systems that use the orthogonal frequency division multiplexing, unlike Weightless and SigFox. In [5] a deception method is proposed in which IoT end-devices can obtain knowledge of a jammer's activity and deceive it by sending fake messages and harvesting the jamming signal to boost its own energetic resources. However, apart from requiring considerable intelligence on the part of the device, the method is focused on the terminals, whereas a more effective way to disrupt an IoT network operation seems to be by means of attacking its gateway, as in the current paper, since individual devices are usually scattered across a large area as opposed to a BS that has a well-defined single location. In [6] the authors propose another game-based approach allowing the performance of an optimal power allocation strategy in response to a jamming action, suitable for multi-channel systems. Other sources recommend varieties of solutions to defeat radio jamming, most of which fall into one of the three categories: frequency hopping (e.g., [7, 8]), power control (e.g., [9, 10]) or backscatter communication, an approach originally proposed in [11] and [12] for increasing an effective transmission range and only recently recognized as an anti-jamming technique in [13] or [14].  
In the authors' opinion, all of the multiple approaches discussed above have three ideas in common: firstly, they assume that a jamming signal occupies certain distinct frequency channels (one or more). Secondly, the jamming signal is assumed to be powerful, preferably exceeding permissible levels imposed on the effective radiated power. Thirdly, they are usually abstract from any concrete system in particular, concentrating on some common technical features common to all IoT systems, with no effort placed on performing measurements on actual systems. Therefore, in the paper it was also shown that a jammer does not necessarily have to exceed permissible radiation levels to effectively jam an IoT base station, nor does it have to concentrate its power on a particular channel. Since most Low Throughput Networks (LTN) systems operate in a narrow 868 MHz frequency band, it suffices to generate the permissible EIRP = 14 dBm across the entire available bandwidth (i.e., 600 kHz for Weightless and 192 kHz for SigFox) to jam such a system, especially if it works with high data rate settings. In the paper the authors measured two real IoT systems (Weightless and SigFox) for their response to jamming in terms of PER/CNIR curves and on this basis they analyzed these systems' performance with respect to all possible operational modes. As it turned out, the built-in transmission mechanisms and parameters, such as the modulation, coding, multiple packet repetitions, spectrum spreading or extremely low bandwidth, can be effective means of counteracting the jamming attacks. They must be, however, carefully selected to make a network operate in a trade-off between the data rate and immunity to jamming.