Coexistence of DC and CSMA in SRD channel access and resilience to LTE interference: A simulator‐based analysis

Funding information Instituto de Telecomunicações; Fundação para a Ciência e a Tecnologia (FCT), Grant/Award Number: UID/EEA/50008/2013 Abstract The foreseen increased use of short-range devices (SRDs) will boost the competition for radio channel access in license-exempt frequency bands. Therefore, it is important to find out the most efficient SRD configurations in terms of their performance in high-contention scenarios; moreover, it is crucial to ensure that SRD networks do not impair the radio systems that operate in neighboring licensed spectrum, and vice versa. This paper addresses the previous issues by simulating a building automation application scenario, where 2 channel access mechanisms, namely duty cycling (DC) and carrier sense multiple access (CSMA), are evaluated independently and in coexisting scenarios, and, also, in the presence of a Long-Term Evolution (LTE) user equipment. The CSMA protocol analysis shows that very high or very low transmission powers decrease its performance, and thus, either this parameter has to be calibrated or the gateways location has to be adjusted; for the DC protocol, its performance is only affected by the number of gateways within the SRD network, which should be as high as possible. Regarding the coexistence of the DC and CSMA schemes, the results show that CSMA-based SRDs can successfully operate in the presence of a significant number of DC-based SRDs, whereas the contrary is not true. Lastly, it is proven that an LTE user equipment may harm the SRD network, although this effect can be mitigated by adjusting the SRDs transmission power; furthermore, the SRDs interference on LTE systems is found to be negligible.