Page 106 - ITU Journal Future and evolving technologies Volume 2 (2021), Issue 5 – Internet of Everything

ITU Journal on Future and Evolving Technologies, Volume 2 (2021), Issue 5

where means tonnage per subscriber in
megabytes (MBs), , is the number of PRBs/
subscriber, is the number of OFDM symbols
per PRB, is the number of bits per ODFM
symbol, is the number of connected minutes per

user. SSO = 0.9, Number of RBs/1msec. = 2, Number
of Simultaneous Users = 4, Number of Connected
Minutes/User in an hour, which is assumed to be
3 minutes/hour, or 180 seconds/hr. In commercial
wireless networks, the simultaneous number of
Fig. 1 – 5G network architecture and network interfaces
subscriber per Transmission Time Interval (TTI)
A backhaul connection can be any type of wireline or changes between 2 and 4 for 4G and between 4 and
wireless connection. 8 for 5G. In this article, we assume there are 4
simultaneous subscribers per TTI. And the number
2.2 Wireless network resource utilization of available PRBs is divided by 4 at each TTI.

2.2.1 Data tonnage resources 189 MBs is the unit resource of data tonnage in a
Spectrum is the most important resource in a wireless network, which is called Value Unit Per
wireless network. In this paper, spectrum refers to User (VUPU). The number of VUPUs will increase
licensed spectrum. And licensed spectrum is more when a wireless service provider deploys a network
valuable than unlicensed spectrum. Spectrum is with high-capacity base stations. A wireless
divided into a number of physical resource blocks in provider owning 40 MHz of spectrum, and hundreds
4G/LTE and 5N/NR standards [1],[3-6]. However, of base stations at a particular region will afford
depending on the Modulation and Coding Scheme more VUPUs than a wireless provider owning
(MCS) selected, the amount of bits that can be 20 MHz of spectrum and a smaller number of base
carried by one Physical Resource Block (PRB) can stations. VUPUs will be sold to investors, and this
change significantly. A resource block is defined as will be the first tokenized unit. The concept of
12 consecutive OFDM symbols in frequency in both mining using base stations is described in [13]. A
4G and 5G standards. One OFDM symbol occupies base station keeps the record of successfully
15 kHz in frequency in 4G/LTE and this is the same created/delivered VUPU to each user terminal. And
for 5G/NR with 15 kHz subcarrier spacing. 5G/NR this information is recorded as part of a block in a
supports multiple OFDM subcarrier spacings. In blockchain held by the base station. Each user is
5G/NR, 15, 30, 60, 120 kHz Subcarrier Spacings assumed to consume 150 units of VUPU, and these
(SCS) are supported. Thus, one resource block units are tradable. The higher the number of
occupies 12 x 15 kHz = 180 kHz of spectrum, and subscribers, the more VUPUs, and the more
10 resource block occupies 1.8 MHz of spectrum in a investment that wireless service provider will have.
frequency domain. This will leave more capital for investment, and will
motivate service providers to deploy more base
1
, = , . ( . ) (1) stations. Current unlimited data plans cost, on
(12 .15) . . ( )
average, 80$ per 20 GBs of data delivered to a
where , represents number of PRBs per subscriber. This equals 80$/20 GB = 4$/1 GB =
0.4$/100 MB, and this is called Revenue per User
1
subscriber, , is the number of PRBs of (RPU).
subscriber U in 1 msec., SA means total spectrum
amount, SSO stands for symbol spacing overhead, = { (∑ =180( +1) ( . )) −
is the subcarrier factor for 5G and is the =180

number of simultaneous users. takes values of 1, − , 0} (3)

2, 4, or 8 for 15, 30, 60, 120 kHz SCSs respectively. where BET is the Break Even Time of a base station
from a financial perspective, T is the time that base
= , . . . (2) station is live and in an operational state, k = 0,1,2,

M. N is the average number of connected users per
base station during time duration of
{180k, 180(k+1)}, CoD refers to Cost of Base Station
Deployment, CoP refers to Cost of Operation, and

94 © International Telecommunication Union, 2021