Laboratory Experiments

The primary objective in this experiment case is to investigate how the jamming affects the tactical communication link of the blue team when different jamming strategies are considered. Also, research is done on how these jamming strategies affect both of the red team’s receivers.

Offensive

Two laboratory experiments are presented for offensive uses where blue team exploits the IBFD transceiver for simultaneously detecting, intercepting and jamming the red team’s RC or HD system. Next, we look at each of these cases, CaseO_RCand CaseO_HD, separately.

In the CaseO_RC, the blue team’s IBFD transceiver is utilized for a spectrum monitoring and signal surveillance purposes as Fig. 4.9 illustrates. Hence, the transceiver is used for detecting hostile opponent transmissions while simultaneously jamming the red team’s receiver. The primary objective here is to investigate if it is possible to detect and prevent the activation of the remotely controlled improvised explosive device with the use of the powerful jamming signal. This feature would be a significant advantage to implement on the MFR.

SI RC TX

RC RX

IBFD

Figure 4.9. The laboratory experiment case𝑂_𝑅𝐶where the blue team’s IBFD transceiver detects and prevents the activation of the red team’s improvised explosive device (RC

TX–RX -link).

Two different experiment scenarios are done. In the first scenario, as Fig. 4.9 case (i) illustrates, the RC transmitter is placed in the same laboratory room as the IBFD transceiver for reference. Figure 4.9 case (ii) illustrates the second scenario where the RC transmitter is placed farther away in corridor which is adjacent to the measurement laboratory. Floor

plan of the measurement laboratory and the corridor was earlier seen in Fig. 4.8. In the latter scenario, it is apparent that an explosion trigger signal must pass through several walls and a glass door to get activated. It should be noted that the very same RC system was also used in the previous CaseD.

With the use of the IBFD transceiver in the second offensive CaseO_HD, the blue team is capable of intercepting the red team’s tactical communication link as Fig 4.10 illustrates.

The blue team is also capable of jamming the red team’s receiver while listening to enemy transmission. The jamming is effective as it makes it difficult for the red team to decode the tactical signal correctly. Next, we look at each experiment case more closely.

SI TX

RX

IBFD

Figure 4.10. The laboratory experiment case𝑂_𝐻𝐷 where the blue team’s IBFD transceiver intercepts and jams the red team’s HD link.

It should also be noted that blue team’s transceiver could also only intercept red team’s tactical communication link without jamming the red receiver. The primary objective of this CaseO_HD is to examine the signal quality at the blue team’s transceiver and the red team’s receiver when different jamming strategies are utilized.

4.2.2 Implementation

In all cases below, a red and blue team’s transmitters, receivers, and transceiver are operating under the same center frequency of 2.4 GHz.

Case D: The IBFD Transceiver Utilization Against Enemy’s Offensive Electronic Attack Operations

Here, tactical signal is wideband GMSK modulated consisting of four adjoining carriers with total𝐵 of 4.8 MHz. Red team utilizes a remote detonator for an explosive which uses GFSK modulated signal with an FH capability. The effectiveness of the red team’s interception is determined by recording a received waveform at the red team’s receiver and calculating an SINR from there. Also, the effectiveness of the blue team’s tactical communication link is done in the same way by recording the signal at the IBFD transceiver and thus calculating the SINR. Hence, different transmission power levels are used from –5 dBm to 15 dBm with 5 dB intervals.

Hereafter, three different jamming scenarios are considered. In the first jamming scenario, the blue team protects its tactical communications link by jamming the red team with 5 MHz narrowband jamming signal that can also be regarded as a tune jammer. In the second jamming scenario, a very wideband signal of 80 MHz is used which can be considered to be barrage jammer. While using the barrage jammer, the existence of the blue team’s tactical communication link can be hidden unlike when using the tune jammer, where the red team is aware of the blue team’s spectrum usage.

As mentioned earlier, the RC system for the explosive activation utilizes the FH pattern of 16 ISM subbands. Therefore, in the last jamming scenario, the jamming signal is tailored for characteristics of the RC transmitter. Here, the blue team jams continuously all of these subbands used by an RC transmitter and a receiver which can be considered as an adaptive jammer. If the FH pattern could be synchronously followed, as in a follower jammer case, a further gain would be achieved. An advantage is that the follower jammer consumes less power when comparing to the adaptive jammer. This power reduction would be the significant advantage when looking at the MFR perspective. In all three jamming scenarios presented here, jamming powers from –10 dBm to 20 dBm with 5 dB intervals are utilized.

Case O

: The IBFD Transceiver Utilization Against RC System

Here, the red team utilizes the RC system for the activation of the explosive that uses the GFSK modulated signal with the FH capability.

In the first scenario, the jamming power is fixed to 18 dBm, which is also a minimum power where the RC receiver loses its connection everywhere in a measurement laboratory room.

Here, the IBFD transceiver is placed to the measurement laboratory, and the RC transmitter

is in the adjacent corridor as in the scenario of Fig. 4.9(ii). Thirty 50 ms signal vectors are recorded after this.

In the second scenario, the measurement is repeated while jamming the RC receiver with the wideband jamming signal of 80 MHz. The jamming powers of{0, 5, 10, 15, 20}dBm and a later range from 20 dBm to 25 dBm with 1 dB intervals are utilized. The following denser range represents an extreme case of the MFR capabilities of suppressing SI. Then, five signal vectors of ten different jamming power outputs are stored at the IBFD transceiver.

Case O

: The IBFD Transceiver Utilization Against HD System

Here, the red team utilizes the single carrier GMSK modulated signal with𝐵= 1.2 MHz.

Hence, the different transmit powers from the red transmitter are utilized from –15 dBm to 20 dBm with the 5 dB intervals. From a blue team’s perspective, two different jammers, tune, and barrage jamming are examined with the jamming signal of an orthogonal frequency- division multiplexing type of waveform. The tune jammer’s𝐵 = 3MHz and the barrage jammer’s𝐵 = 80MHz. The total jamming power varies between –10 and 20 dBm at 5 dB intervals. Also, in this case, the several received signal vectors from the red receiver and the blue IBFD transceiver are collected which are later utilized for SINR calculation.