Design Considerations for Vehicle-to-Vehicle IEEE 802.11p Radar in Collision Avoidance

Abstract

Vehicle-to-Vehicle (V2V) communication is expected to make a global impact on improving driver safety by alerting motorists of potential collisions, but the full safety benefit can only be realized if every vehicle is equipped with a transceiver. Motivated to provide collision avoidance for drivers of vehicles only equipped with a V2V transceiver, we develop a framework for using the V2V communication signal simultaneously as a radar without suggesting any changes to the existing V2V standards or spectrum. The theoretical system treats the IEEE 802.11p waveform as a Multi-Frequency Continuous Wave signal to estimate the velocity and range of a vehicular threat not equipped with a V2V transceiver. While spectrum and upper layers of the protocol stack can vary depending on geographic region, the IEEE 802.11p physical layer protocol is adopted globally. Restrictions in waveform design due to IEEE 802.11p standardization are considered and leveraged for enhancing the radar operations. Through a rigorous simulation treatment, the V2V radar system would be capable of detecting a head-on collision with a 35.12% accuracy using only safety message packets. If non-safety packets are included in the detection operation, then up 100% accuracy is achievable.Index Terms-Vehicle-to-Vehicle, IEEE 802.11p, Collision Avoidance, OFDM Radar 978-1-4799-5952-5/15/$31.00 ©2015 IEEE

Forward Collision Vehicular Radar With IEEE 802.11: Feasibility Demonstration Through Measurements

“…This is readily supported in IEEE 802.11a/g but is also possible in Channels 175 and 181 in IEEE 802.11p [5]. Note that at ranges less than 5 m, a 20 MHz channel suffers from performance degradation, i.e., the cosine term in (16) does not complete one full cycle within the meannormalized channel energy. We omit ranges less than 5 m from our detection environment because this performance is acceptable for various applications of vehicular radar, such as mid and long-range radar.…”

“…In the first three plot lines on this figure, only one RCS value is included (2nd target σ = 0). The last plot line reflects two targets with RCS σ = 1.0 m 2 : the first with variable range and the second target with fixed range at 25 m. This figure shows that strong targets (σ = 1.0 m 2 ), in the absence of other targets, can be accurately estimated at distances greater than 15 m. Below 15 m, the cosine term in (16) does not complete one full cycle. Consequently, mean offsets are magnified, resulting in occasionally poor estimates.…”

“…6 is not meter-level accurate. As mentioned above, for ranges less than 15 m, the cosine term in (16) does not complete one full cycle within the meannormalized channel energy, degrading the performance for the optimization algorithm. In this case, alternative approaches to range estimation are necessary for accurate detection at close ranges.…”

“…2. RMS range error between actual range of single target in a 10 MHz channel and optimal range based on the simulated mean-normalized channel energy defined in (16). At 10 MHz, the estimation error does not exceed 3m when the target range is larger than 10m.…”

“…Based on (16) in Section II, we propose a brute-force optimization algorithm that matches a sinusoid to the received mean-normalized channel energy. Consider mean offset (A ∈ R), cosine magnitude candidate (B ∈ R), initial phase candidate (C ∈ [0, 2π)), and phase increment (D ∈ R).…”