Analytical and Experimental Performance Evaluation of BLE Neighbor Discovery Process Including Non-Idealities of Real Chipsets

Abstract

The purpose of this paper is to evaluate from a real perspective the performance of Bluetooth Low Energy (BLE) as a technology that enables fast and reliable discovery of a large number of users/devices in a short period of time. The BLE standard specifies a wide range of configurable parameter values that determine the discovery process and need to be set according to the particular application requirements. Many previous works have been addressed to investigate the discovery process through analytical and simulation models, according to the ideal specification of the standard. However, measurements show that additional scanning gaps appear in the scanning process, which reduce the discovery capabilities. These gaps have been identified in all of the analyzed devices and respond to both regular patterns and variable events associated with the decoding process. We have demonstrated that these non-idealities, which are not taken into account in other studies, have a severe impact on the discovery process performance. Extensive performance evaluation for a varying number of devices and feasible parameter combinations has been done by comparing simulations and experimental measurements. This work also includes a simple mathematical model that closely matches both the standard implementation and the different chipset peculiarities for any possible parameter value specified in the standard and for any number of simultaneous advertising devices under scanner coverage.

Low-cost test measurement setup for real IoT BLE sensor device characterization

“…Nevertheless, the duration of all these "blind times" in this case does not depend on the configured Scan_Window and Scan_Interval parameters. Other devices also present these frequency change gaps (depicted in black) but they also introduce other periodic blind times (depicted in red) associated with unknown processes of the manufacturer firmware implementation [3,19].…”

“…They may also be different when the received frame is demodulated correctly or not. More details can be found in [3,19].…”

“…These non-idealities are caused by limitations of real devices and depend on the firmware and hardware implementation of the chipset manufacturers. We have demonstrated [3] that these non-idealities can be neglected when just a few devices are present, but become very noticeable in stressed scenarios.…”

“…In previous works, see [3,19], we have also followed these procedures to characterize and analyze BLE devices.…”

Proposal and Evaluation of BLE Discovery Process Based on New Features of Bluetooth 5.0

“…On the other hand, analytical and simulation studies do not take into account the non-idealities present in real devices. In [ 13 ], we have shown that these non-idealities have a severe impact on discovery capacity. In this paper, we will focus on a comparative evaluation of scannable undirected vs. non-connectable advertisements to be employed in high density networks to provide the location and transmission of information where a large number of devices are involved.…”