Page 94 - Kaleidoscope Academic Conference Proceedings 2021

2021 ITU Kaleidoscope Academic Conference

Table 1 – Comparison of several wireless communication technologies

Technology Frequency Transmission distance Transmission rate Power consumption Maximum nodes
WiFi 2.4GHz 20-200m <54 Mbps hours/AA battery 2007
Bluetooth 2.4GHz 20-200m <1 Mbps weeks/AA battery 7
ZigBee 2.4GHz 10-75m <0.25 Mbps about 2 years/AA battery 65000
LoRa 150MHz-1GHz about 15km 0.3-50 Kbps about 10 years/AA battery 200000
NB-IoT Operator Bands 10-15km <100 Kbps about 10 years/AA battery 200000

applied to computing and storage-constrained IoT nodes, [9]. This centralized management makes privacy and security
especially in scenarios such as LPWAN that appear to be issues prominent. Not until the introduction of distributed
redundant with insufficient performance. How to optimize ledger technology and its integration with the IoT did it
the data transmission efficiency of distributed ledger during effectively address many of the issues that exist with the IoT
operation is an urgent issue that needs further research. At the [10]. Sensitive data generation, exchange, and storage exists
same time, it is especially important to sort out and summarize between IoT devices, which can rely on the P2P characteristics
the standardization of distributed ledgers at the present stage. of distributed ledger to ensure its privacy, robustness, and
In response to the existing problems and needs, the main single-point-of-failure fault tolerance [11]. Each operation
contributions of this paper are as follows. of data creation, modification and deletion in IoT can be
(1) We propose an optimized packet transmission mechanism registered and verified in the distributed ledger to achieve the
for the ledger-based points transfer system in LPWAN to detection of IoT data tampering and abuse [12]. In addition,
reduce the data transmission volume of the whole system. in the distributed ledger framework, IoT devices can store
(2) Simulation results show that our proposed mechanism data securely in different nodes without human intervention
can well reduce the packet traffic in LPWAN and ensure the and use the characteristics of distributed ledger to ensure its
proper operation of the overall distributed ledger. decentralized trust, authenticity, security, privacy, etc. [13].
(3) We summarize the standardization work of ITU-T, ISO, The full-node data capacity of distributed ledger is very large
IEEE on distributed ledger. and tends to continue to get larger, making full-node network
The rest of this paper is organized as follows. In synchronization as well as storage difficult. The application
Section 2, we describe the related work on LPWAN, of distributed ledger in an LPWAN network is facing two
ledger-based technologies for IoT, lightweight distributed main problems: 1) high energy consumption problem. How
ledgers. Section 3 describes a ledger-based points transfer to reduce energy consumption while ensuring security is
system in LPWAN. Section 4 proposes the solution to an urgent problem. 2) Database storage space problem.
optimize packet transmission. Simulation evaluations are The distributed ledger records every transaction that occurs
illustrated in Section 5. In Section 6, we introduce the from the time of creation. If every node’s data is fully
standardization of distributed ledger. Finally, we conclude synchronized, then the storage space capacity requirement
the paper in Section 7. of distributed ledger may become a key issue that restricts its
development. [14] proposed TangoChain, an experimental
2. RELATED WORK lightweight distributed ledger for IoT devices, which utilizes
a directed acyclic graph as the underlying ledger data
LPWAN is the hot trend of IoT development in recent years. structure. [15] proposed a lightweight and scalable directed
Unlike ZigBee, WiFi, Bluetooth and other communication acyclic graph-based IoT distributed ledger that can work
technologies which are dedicated to high speed, it is more with resource-constrained IoT gateways to provide fast and
concerned with low-power consumption, long distance, low scalable IoT data integrity verification. Although there are
bandwidth and easy deployment. Among them, NB-IoT some lightweight distributed ledger technologies that are
and LoRa are typical representatives of LPWAN technology continuously promoting the use of distributed ledgers in
[6]. NB-IoT adopts cellular communication technology and IoT. However, there are few studies on optimizing packet
works in an authorized frequency band, which is built by transmission for distributed ledgers in LPWAN.
telecommunication operators [7]; LoRa adopts linear spread
spectrum technology and works in an unlicensed frequency 3. LEDGER-BASED POINTS TRANSFER SYSTEM
band, which is set up by users themselves and can work in IN LPWAN
remote areas not covered by mobile cellular networks [8]. As
shown in Table 1, LoRa and NB-IoT have obvious advantages The design principle of this system is to realize the points
in terms of power consumption, and the large number of nodes transfer from Tag A to Tab B. At the same time, the ledger
and long transmission distance make them suitable for mass strictly manages the user’s points balance. This point transfer
deployment and connection of end devices. However, in the system is based on LPWAN, which can transfer points even
"small data" monitoring scenario, the data communication in case of disasters. During the system design, we must focus
rate requirement is not high. on the following limitations. 1) The tag’s functionality is
Most IoT solutions rely on a centralized server-client limited. Considering the cost and practicality, the tags of
paradigm to access IoT devices in a cloud-based approach the system are battery-powered and do not require the user

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