Sharing location traces with context-aware service providers has privacy implications. Location-privacy preserving mechanisms, such as obfuscation, anonymization and cryptographic primitives, have been shown to have impractical utility/privacy tradeoff. Another solution for enhancing user privacy is to minimize data sharing by executing the tasks conventionally carried out at the service providers' end on the users' smartphones. Although the data volume shared with the untrusted entities is significantly reduced, executing computationally demanding server-side tasks on resourceconstrained smartphones is often impracticable. To this end, we propose a novel perspective on lowering the computational complexity by treating spatiotemporal trajectories as space-time signals. Lowering the data dimensionality facilitates offloading the computational tasks onto the digital-signal processors and the usage of the non-blocking signal-processing pipelines. While focusing on the task of user mobility modeling, we achieve the following results in comparison to the state of the art techniques: (i) mobility models with precision and recall greater than 80%, (ii) reduction in computational complexity by a factor of 2.5, and (iii) reduction in power consumption by a factor of 0.5. Furthermore, our technique does not rely on users' behavioral parameters that usually result in privacy-leakage and conclusive bias in the existing techniques. Using three real-world mobility datasets, we demonstrate that our technique addresses these weaknesses while formulating accurate user mobility models.Problem 1: Mobility Signal Generation. Given a trajectory T u of an individual u, a temporally ordered sequence of tuples, 3 Art. 23: www.privacy-regulation.eu/en/article-23-restrictions-GDPR.htm such that, T u = (l 1 ,t 1 ), (l 2 ,t 2 )...(l n ,t n ) , where l i = (lat i , lon i ), the latitude-longitude coordinate pair and t, the timestamp such that t i+1 > t i , translate T u into a 2-D signal S u (t), modeled as a function of changing distance with respect to time.Requirements and Challenges. (i) Constructing a continuous graph from the noisy and non-uniformly sampled location trajectories, (ii) preserving all the key knowledge contained in the trajectory samples, and (iii) retaining the spatial locality between the discretized points.Problem 2: Signal Interpretation. Given a user's spatiotemporal signal S u (t), interpret and model the distinct signal elements in the temporal and spectral domain, i.e. local maxima/minima, rising/falling edges, static signal component, candidate frequencies, spectral coefficients and harmonics, with respect to human mobility behaviors.Requirement and Challenge. In order to facilitate interdomain switching, attach and validate a semantic meaning to each of the above signal components.Problem 3: Mobility Modeling. Given the signal S u (t) and the valid interpretation of each element, construct the user's mobility model in terms of a graph G u (ROI, Tr), where ROI = {ROI 1 , ROI 2 ...ROI n } is the set of all the re...