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100 TRƯỜNG ĐẠI HỌC SƯ PHẠM KỸ THUẬT - ĐẠI HỌC ĐÀ NẴNG

lifespan. IoT focuses on achieving more functionality mirrors have limitations, particularly in adverse
with fewer resources, which sets it apart from weather conditions like fog, rain, or when obstructed
traditional internet-connected devices. This drive to by vegetation. These factors can impact the reflected
"do more with less" creates constraints that can limit image in the mirror, thereby reducing its
the use of mobile networks and traditional effectiveness.
technologies like Wi-Fi. These technologies may not
meet the power requirements and capabilities of IoT Sound warnings can quickly capture the driver's
devices [1]. attention, helping them immediately detect the
To overcome these limitations, specialized IoT presence of other vehicles. Sound is less affected by
networks and protocols have been developed, such as weather or lighting conditions. Therefore, sound-
Low Power Wide Area Networks (LPWAN), as well based warnings are an effective alert method in places
as protocols like Zigbee and Z-Wave. These with limited visibility. However, most forms of sound
technologies are specifically designed to offer warnings, such as car horns or current warning
efficient and low-power connectivity for IoT devices. alarms, rely on the driver's initiative. When drivers
Consequently, they enable these devices to operate are careless or distracted, they are very likely to forget
effectively with limited resources, while also sound warnings for other vehicles.
supporting large-scale device deployments[2]. This article will present the automatic sound
LoRa is an LPWAN protocol aimed at deploying warning system to vehicles participating in traffic.
power-constrained end devices (e.g., battery-powered The system will be deployed in areas with limited
devices), where the end devices do not need to visibility. The system will include warning devices
transmit more than a few bytes at a time and the data and distance sensors, which will communicate with
can be initiated by the end device (as when the end each other via LoRa communication technology.
device is a sensor) or by an external entity that wants
to communicate with the end device (as when the end Warning devices will be deployed at intersections
device is an active mechanism). LoRa's long in hidden areas and distance sensors placed at
transmission and low power consumption make it an different locations, helping to detect approaching
interesting candidate for smart sensing technology in vehicles. When a vehicle approaches, the sensor
residential infrastructure (such as health monitoring, device will send a signal to the warning device via
smart metering, environmental monitoring , etc.), as LoRa communication. After receiving a signal from
well as in industrial applications [3]. the sensor device, the warning device will use the
Areas with limited visibility, such as intersections, sound warning method to other vehicles participating
mountain passes, and hills, are prone to traffic in traffic.
accidents. In these areas, drivers often face challenges
in identifying vehicles coming from different
directions, especially during foggy, rainy, or dark
weather conditions. Mountainous regions, with their
difficult terrain featuring numerous curves and steep
slopes, significantly increase the risk of accidents due
to potential loss of control. Factors like poor road
conditions, insufficient lighting, and unclear traffic
signs further contribute to the elevated accident rate in
these areas. Additionally, high-altitude mountain
passes and hills are often enveloped in fog, which
severely restricts visibility and leaves drivers with
insufficient time to react to unexpected situations.
This heightens the risk of collisions, necessitating
skilled driving and heightened concentration from
motorists.
Fig. 1. System implementation example
Areas with limited visibility often have fewer II. LONG RANGE (LORA)
vehicles, which can lead drivers to become negligent
and subjective towards signage systems. Moreover, A. Overview of LoRa in traffic
not everyone comprehends the meaning of each sign With the ability to transmit signals up to several
symbol on the road clearly. Convex mirrors prove kilometers in ideal environmental conditions, LoRa
highly effective in reducing the risk of traffic enables the deployment of an economical and high-
accidents at intersections or areas with limited performance IoT network infrastructure. Transmission
visibility. They provide drivers with a wider viewing power and data rate can be adjusted to simultaneously
angle, thereby enhancing visibility in situations where meet special requirements from IoT devices [4].
direct visibility is compromised. However, convex
ISBN: 978-604-80-9122-4