Hidden-nodes in coexisting LAA & Wi-Fi: a measurement study of real deployments
| Autor: | Vanlin Sathya, Muhammad Iqbal Rochman, Monisha Ghosh |
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| Rok vydání: | 2021 |
| Předmět: |
Networking and Internet Architecture (cs.NI)
FOS: Computer and information sciences Hidden node problem business.industry Throughput degradation Computer science ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS Context (language use) Throughput Transmission (telecommunications) Measurement study Bandwidth (computing) business Computer network |
| Zdroj: | ICC Workshops |
| DOI: | 10.48550/arxiv.2103.15591 |
| Popis: | LTE-Licensed Assisted Access (LAA) networks are beginning to be deployed widely in major metropolitan areas in the US in the unlicensed 5 GHz bands, which have existing dense deployments of Wi-Fi. This provides a real-world opportunity to study the problems due to hidden-node scenarios between LAA and Wi-Fi. The hidden node problem has been well studied in the context of overlapping Wi-Fi APs. However, when Wi-Fi coexists with LAA, the hidden node problem is exacerbated since LAA cannot use the well-known Request-to-Send (RTS)/Clear to-Send (CTS) mechanism to resolve contentions, resulting in throughput degradation for Wi-Fi. In this paper, we describe detailed measurements and conclusions from experiments on the campus of the University of Chicago which presents a perfect hidden node scenario where Wi-Fi access points (APs) controlled by us and an LAA base-station (BS) deployed by AT&T are hidden from each other, but the clients are not. We performed careful experiments in three different regions of the coexistence area: (i) clients midway between LAA & Wi-Fi; (ii) clients close to the Wi-Fi AP; and (iii) clients close to the LAA BS. Our results show that in a situation where LAA uses an aggregate of three unlicensed channels (60 MHz bandwidth) which overlap with an 80 MHz Wi-Fi transmission, the Wi-Fi throughput at client devices suffers considerably. Overall, Wi-Fi performance is impacted by the hidden node problem more severely than LAA. In the best outdoor conditions, the throughput of LAA and Wi-Fi is reduced by 35% and 97% respectively when coexisting with each other as compared when the other system is not present. Furthermore, we conclude that when both LAA and Wi-Fi use multiple 20 MHz channels and there are multiple Wi-Fi APs coexisting with LAA on the same set of channels, the choice of Wi-Fi primary channels can have a significant impact on LAA throughput. IEEE ICC 2021 Workshop on Spectrum Sharing Technology for Next-Generation Communications |
| Databáze: | OpenAIRE |
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