5G network operators are constantly under pressure from regulatory agencies who restrict the deployment of base stations (gNBs) close to incumbent services, such as radio astronomy services (RAS), to avoid interfering with them. Recent works for coexistence with RAS employ limited channel modeling approaches and use explicit out-of-band communication between the gNB and RAS. However, the strict latency requirements of 5G make explicit communications less desirable due to their overheads. Deploying gNBs close to RAS is also not yet supported. In this paper, we propose a proactive open-loop beamforming and interference nullification technique in which a gNB nullifies its downlink signal at a nearby RAS telescope while beamforming to its users (UEs). We estimate the gNB-RAS channel using raytracing on open-source terrain maps. We formulate a problem that maximizes the minimum rate for UEs under the constraint of maximum allowable interference power at the RAS and show that its time complexity scales cubically with the number of gNB antennas. Hence, we propose a heuristic solution that achieves 4 orders better latency and 100 dBW lower interference power than the max-min rate solution with similar sum rate on users. Our proposed solution consistently achieves less than -310 dBW interference power, even when the gNB-RAS distance is less than 1 km, satisfying international regulations, and is robust against moving users that vary in location and elevation.

5G and Wi-Fi systems are embracing coexistence in the unlicensed portions of the 5–7 GHz bands recently allocated by FCC to support the increasing data rate demands for the growing number of wireless users. To achieve fair and effective spectrum sharing, both 5G and Wi-Fi rely on carrier sensing for medium access. However, differences in sensing thresholds create an unfair advantage for 5G nodes, as they access the medium more aggressively and degrade the data rate and latency of Wi-Fi users. We first demonstrate how an adversary can stealthily exploit this unfairness to further reduce the spectrum occupancy of Wi-Fi nodes, effectively denying Wi-Fi services. Accordingly, in this paper, we propose a novel implicit channel coordination (ICC) approach to both mitigate starvation attacks and improve spectrum access fairness under practical considerations like noise and strong adversaries who try to circumvent our technique. In ICC, Wi-Fi access points (APs) influence 5G gNBs into choosing a precoding matrix that nearly nullifies 5G downlink signals at the APs, enabling concurrent gNB and AP transmissions while accounting for a hidden terminal problem this creates. We theoretically analyze and show that our ICC mitigates novel attacks we have identified, and experimentally demonstrate on a USRP testbed its resilience against starvation attacks. Our design outperforms prior work by achieving an overall 30% higher data rate of the 5G and Wi-Fi coexistence system, 3x improvement in spectrum access fairness, and 1.5x in system capacity, all while conforming with the latency requirements of 5G.

Due to the scarcity of spectrum bands, 5G and Wi-Fi systems are embracing coexistence in the unlicensed 5 and 6 GHz bands to support high data rate demands and growing number of users. To provide fair and effective coexistence in shared frequency bands, both technologies rely on carrier sensing. However, differences in sensing thresholds creates an unfair advantage for 5G nodes who access the shared wireless medium more aggressively and degrade the data rate and latency of Wi-Fi nodes. We show in this paper that an adversary who intends to deny service to Wi-Fi can stealthily exploit this unfairness to drastically reduce the spectrum occupancy and data rate of Wi-Fi nodes. We then propose a novel implicit channel coordination (ICC) approach to mitigate the attack and improve sharing fairness. In ICC, Wi-Fi nodes influence 5G gNB into choosing a precoding matrix that nearly nullifies downlink signals at Wi-Fi nodes. We demonstrate our starvation attack on a USRP testbed and further evaluate our proposed ICC approach using simulations. We show that ICC doubles the data rate of a Wi-Fi network subject to an active attack.

Growing deployment of vehicle-to-vehicle (V2V) communications is expected to significantly increase the volume of Basic Safety Messages (BSM) in highways and dense roads. Computational overhead of verifying the integrity of BSMs will therefore be high while current V2V equipment can process only a limited number of BSMs per second. As a result, critical BSMs carrying vital information may fail to be processed on time, creating unsafe outcomes. In this paper, we expose this vulnerability, discuss critical scenarios, develop novel attacks that exploit this vulnerability, and propose a sieving technique to mitigate these verification gridlock attacks. We show on a USRP testbed that our proposed sieving mechanism to counter sophisticated attackers who exploit this vulnerability achieves 80% accuracy at SNR greater than 6 dB, effectively mitigating the attack.