Comparative Study on AFH Techniques in Differ-ent Interference Environments

In this paper the use of Adaptive Frequency Hopping (AFH) as a solution to interference problems caused by the proximi-ty and simultaneous operation of radio systems in the 2.4 GHz band is discussed. The main algorithms for AFH that attempt to avoid frequency collisions are considered. A com-parative analysis of their respective performance is conduct-ed. The trends and trade-offs for different interference levels are discussed. Performance is analyzed in terms of collision frequency and channel usage distribution frequency.status: publishe

A Study on the Impact of the Number of Devices on Communication Interference in Bluetooth Low Energy

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Bluetooth Low Energy Interference Awareness Scheme and Improved Channel Selection Algorithm for Connection Robustness

Bluetooth Low Energy (BLE) is a popular wireless communication protocol heavily used in Internet of Things applications. Nowadays, robustness is considered a key requirement in wireless communication. However, radio interference from various sources may affect the performance of BLE devices, leading to channel congestion. Therefore, there is a broadly recognized need of methodologies capable of sensing and avoiding interference. In this paper, two improvements at the data link layer for interference detection and channel selection are proposed to enhance the BLE connection robustness. This paper also presents a wide range of experimental evaluations aiming at validating the improvements and providing insights on both these improvements. Particularly, the communication performance of the BLE link layer is assessed in terms of channel usage distribution, supervision timeout ratio (STR) and packet loss rate (PLR) under different interference environments. Results from these experiments (reliability over 97% and 99% under two different harsh environments) highlight the effects of both improvements on the BLE robustness. Meanwhile, the authority of scheduling the whole mechanism is given to the link layer and even the higher application layer. This paper provides a set of solutions for BLE confronting interference in link layer