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Investigation of spectrum values in rural environments
Yiqiao Wei,황승훈 한국통신학회 2018 ICT Express Vol.4 No.4
Frequency bands above 1.5 GHz have traditionally been used for 3G and 4G mobile communication services and new frequency bands will be allocated for 5G services in the near future. In this paper, the spectrum value in rural environments is analyzed using an engineering-economic modeling. In order to evaluate the spectrum values, three metrics are selected: maximum cell radius, annual infrastructure cost per square kilometer, and spectrum value per MHz-POP. Frequency bands ranging from 1.5 GHz to 3 GHz and 3 GHz to 11 GHz, are evaluated.
Guard band protection for coexistence of 5G base stations and satellite earth stations
유서지,Wei Yiqiao,황승훈 한국통신학회 2023 ICT Express Vol.9 No.6
In this paper, the coexistence between fifth generation (5G) network and fixed satellite service (FSS) is investigated. To reduce the interference between 5G base stations (BSs) and FSS earth station (ES), a guard band protection method is proposed. Additionally, the distance and angular protection methods are amalgamated. The performances are evaluated by simulation in realistic 3GPP. Also, the impacts of four antenna types are analysed for a 5G BS. The numerical results show that the guard band protection can solve the interference for the 5G/FSS coexistence, when the distance protection is combined. In addition, when the hybrid protection method is employed, the coexistence between 5G BS and FSS ES is guaranteed.
A survey on LPWA technology: LoRa and NB-IoT
쉬미 샤란 신하,Yiqiao Wei,황승훈 한국통신학회 2017 ICT Express Vol.3 No.1
By 2020, more than twenty five billion devices would be connected through wireless communications. In accordance with the rapid growth of the internet of things (IoT) market, low power wide area (LPWA) technologies have become popular. In various LPWA technologies, narrowband (NB)-IoT and long range (LoRa) are two leading technologies. In this paper, we provide a comprehensive survey on NB-IoT and LoRa as efficient solutions connecting the devices. It is shown that unlicensed LoRa has advantages in terms of battery lifetime, capacity, and cost. Meanwhile, licensed NB-IoT offers benefits in terms of QoS, latency, reliability, and range.