Building Footprint Simplification Techniques and Their Effects on Radio Propagation Predictions

Abstract

Building footprint simplification is of critical importance to radio propagation predictions in wireless communication systems as the prediction time is closely related to the number of both buildings and vertices involved. Intuitively, if the complexity of footprints (i.e. the number of vertices in the footprints) is reduced, predictions can be generated more quickly. However, such reductions often affect the accuracy of results as the simplification error constrains the efficiency that can be achieved. To achieve a good vertex reduction rate for the footprints involved and at the same time preserve the shapes of footprints in terms of their areas, orientations and centroids, we propose a number of efficient single-pass methods to simplify building footprints. To satisfy constraints on edges, areas and centroids of simplified footprints, multi-pass methods are suggested. Hybrid methods take advantage of complementary properties exhibited by different footprint simplification methods. We assess the baseline effectiveness of our proposed techniques, and carry out an extensive comparative evaluation with real geographic information system data from different municipalities. Through experimentation, we find that hybrid methods deliver the best performance in both vertex reduction rate and simplification error. We examine the effects that these footprint simplification methods have on the ray-tracing based radio propagation prediction systems in terms of processing time and prediction accuracy. Our experiments show that footprint simplification methods indeed reduce prediction time up to three-fold, and maintain prediction accuracy with high confidence as well. We also investigate the relationship between footprint simplification error and the prediction accuracy. We find that the prediction accuracy is sensitive to the distortion (i.e. change of shape) of building footprints. This helps us to better understand the trade-off between precision of the building database and the accuracy of predictions generated by ray-tracing based radio propagation prediction systems.

Adaptive Region Construction for Efficient Use of Radio Propagation Maps

“…The authors of [11] propose using convex hulls for a simplified representation of "building footprints" on radio propagation which is a crucial step in wireless communication. Footprint reduction is crucial for reducing prediction time and controlling prediction accuracy in radio communication.…”

3D Ray-Tracing Parallel Propagation Model for MIMO Systems and Multi-Floor Scenarios

“…The great growth in mobile communications ask for fast and accurate prediction of radio wave propagation for system deployment. Such predictions can represent an important role in determining network parameters including coverage, transmitted-data rates, optimal base station locations, and antenna patterns [1]. The necessity of efficient propagation models is still more evident when it is increased the interest to provide mobile services for complex environments (e.g.…”

“…Although ray-tracing approaches are very useful in the design, analysis, and deployment of wireless networks, it has been recognized that these models are computationally very expensive and require a considerable Belém-PA/Brazil, E-mails: andre.cavalcante@indt.org.br, marco.souza@indt.org.br, jweyl@ufpa.br, gervasio@ufpa.br. amount of processing time to attain reasonable accurate prediction results [1], [6].…”

“…Several approaches have been proposed to shorten the computation time for ray-tracing prediction models simulations. In [1], the complexity of the building databases was reduced by simplifying footprints. Data filtering and cleansing techniques have been proposed in [7].…”

Radio-wave propagation prediction using ray-tracing techniques on a network of workstations (NOW)

“…The complexity of building databases can be reduced by simplifying footprints [16]. Data filtering and cleansing techniques have been proposed in [50].…”