Batched Point Location in SINR Diagrams via Algebraic Tools
Boris S. Aronov, Matthew J. Katz · Lecture notes in computer science · 2015
The SINR model for the quality of wireless connections has been the subject of extensive recent study. It attempts to predict whether a particular transmitter is heard at a specific location, in a setting consisting of n simultaneous transmitters and background noise. The SINR model gives rise to a natural geometric object, the SINR diagram, which partitions the space into n regions where each of the transmitters can be heard and the remaining space where no transmitter can be heard. Efficient point location in the SINR diagram, i.e., being able to build a data structure that facilitates determining, for a query point, whether any transmitter is heard there, and if so, which one, has been recently investigated in several papers. These planar data structures are constructed in time at least quadratic in n and support logarithmic-time approximate queries. Moreover, the performance of some of the proposed structures depends strongly not only on the number n of transmitters and on the approximation parameter $$\varepsilon $$ , but also on some geometric parameters that cannot be bounded a priori as a function of n or $$\varepsilon $$ . In this paper, we address the question of batched point location queries, i.e., answering many queries simultaneously. Specifically, in one dimension, we can answer n queries exactly in amortized polylogarithmic time per query, while in the plane we can do it approximately. All these results can handle arbitrary power assignments to the transmitters. Moreover, the amortized query time in these results depends only on n and $$\varepsilon $$ . Finally, these results demonstrate the (so far underutilized) power of combining algebraic tools with those of computational geometry and other fields.