Short text messaging plays a primary role in ensuring safety in Vehicular Ad Hoc Networks (VANETs). The issue of road safety captures the mind of many as a global public health hazard. The concept of VANETs enables implementation of emerging wireless communication technologies to realize applications geared towards safety in vehicular environment in response to growing concerns of road accident injuries. Preliminary research findings in VANETs indicate that majority of vehicular accidents involve non-impaired drivers who, if alerted of the impeding danger, would avoid such crashes. Solutions have been proposed in collision avoidance through short text messages supported in vehicle-to-vehicle(V2V) and vehicle-to-infrastructure (V2I) communications. While the existing protocols relying on pilot carriers adequately address the fixed and low mobility scenarios, high vehicular mobility is perturbed by Doppler shift which renders the existing protocols ineffective as far as the received signal quality is concerned. In this paper a novel method based on matrix inversion is analytically developed to enhance signal detection in short text messaging by yielding more accurate Doppler shift estimates in high mobility VANETs. Numerical results indicate that the proposed method outperforms the methods based on existing algorithms.
Keywords : Doppler shift; estimation; MIMO; OFDM; VANETs