A Glimpse at Bicycle-to-Bicycle Link Performance in the 2.4GHz ISM Band

Bicycle-to-bicycle (Bi2Bi) communication can be implemented by well-established technologies in the 2.4GHz ISM band: IEEE 802.11, Bluetooth or IEEE 802.15.4. These technologies have distinct performance due to different physical and data link layers. In this paper, we characterize the mentioned 2.4 GHz-operating technologies over opportunistic links established between bicycles using commodity hardware. We find that, in Bi2Bi links, Blue-tooth, IEEE 802.11 at 24 Mbit/s, and IEEE 802.11 with automatic rate adaptation can communicate only in the immediate surroundings (under 15m of range), to maxima of 1.5 Mbit/s, 17 Mbit/s and 25 Mbit/s, respectively. IEEE 802.15.4 and IEEE 802.11 at 1 Mbit/s sustain connectivity up to 30 and 40 meters and peak transfer rates of 50 kbit/s and 800 kbit/s respectively. In addition, we observed that, in all measurement scenarios, link performance depended strongly on whether bicycles were approaching or moving away, rather than on whether one was at the front or back of the other.

I. Introduction

Bicycles are a widely used commute solution [1]. Bicycle-to-bicycle (Bi2Bi) and bicycle-to-infrastructure networking may support safety and infotainment applications, thus safeguarding cyclists and other road users and improving their mobility experience. Existing V2V technology was tailored for high relative speeds and is power-intensive, partly due to its higher transmit power [2]. In this paper, we evaluate opportunistic connectivity between bicycles supported by less power-intensive wireless technologies operating in the 2.4GHz ISM band, and assess the performance of commodity hardware in Bi2Bi communication. In this band, the most prominent wireless technologies are IEEE 802.11b/g/n [3], Bluetooth [4] Class 2, and IEEE 802.15.4 [5]. Our contributions are the following: •

Experimental characterization of the link performance between transceivers mounted on bicycles in motion, for five different technology setups;

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Identification of whether bicycles are approaching or moving away as the main factor impacting link performance;

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Discussion on the potential applications that each technology can support and on the limitations and challenges of this work.