5G Fixed Wireless Access for Bridging the Rural Digital Divide
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Despite the ubiquitous level of mobile and fixed broadband (FB) connectivity that exists for many people today, the availability of high quality FB services in rural communities is generally much lower than in urban communities, which has led to a digital divide. At the same time, rural communities in Canada have a high level of 4G LTE coverage and the mobile digital divide between urban and rural communities is much smaller compared to the FB divide. Traditionally, FB and mobile services were offered over separate technologies by different operators, and evolved separately from one another. However, recently, a convergence between mobile and FB has started to emerge via 4G Fixed Wireless Access (FWA), which has made it possible to take advantage of the high level of cellular coverage in rural communities to offer (limited) FB at lower costs than traditional wired FB. To bridge the digital divide, rural FWA must be able to provide the same end-to-end experience as urban FB. In in this regard, 4G FWA has been inadequate; however, the recent emergence of 5G, which brings new spectrum, a more efficient radio interface, and multi-user massive MIMO, can make a difference. In the first half of this thesis we outline a vision for how 5G could fix the rural connectivity gap by truly enabling FWA in rural regions. We examine new and upcoming improvements to each area of the 5G network architecture and how they can benefit rural users. Despite those advancements, 5G operators will face a number of challenges in planning and operating rural FWA networks. Therefore, we also draw attention to a number of open research challenges that will need to be addressed. In the latter half of this thesis, we study the planning of a rural 5G multi-user massive MIMO FWA TDD system to offer fixed broadband service to homes. Specifically, we aim to determine the user limit, i.e., the maximum number of homes that can simultaneously receive a target minimum bit rate (MBR) on the downlink (DL) and a target MBR on the uplink (UL) given a set of network resources (e.g., bandwidth, power, antennas) and given a radius. To attain that limit, we must understand how resources should be shared between the DL and UL and how user selection (as well as stream selection since both the base-station (BS) and the homes are multi-antenna), precoding and combining, and power distribution should be performed. To simplify the problem, we use block diagonalization and propose a static user grouping strategy that organizes homes into fixed groups in the DL and UL (we use different groups for the two directions); then we develop a simple process to find the user limit by determining the amount of resources required to give groups the MBRs. We study the impact of group sizes and show that smaller groups use more streams and enable more homes to receive the MBRs when using a 3.5~GHz band. We then show how the user limit at different cell radii is impacted by the system bandwidth, the number of antennas at the BS and homes, the BS power, and the DL and UL MBRs. Lastly, we offer insight into how the network could be operated for an arbitrary number of homes.
Cite this version of the work
Andrew Lappalainen (2021). 5G Fixed Wireless Access for Bridging the Rural Digital Divide. UWSpace. http://hdl.handle.net/10012/17471