Design, development, and implementation of a wireless mesh communication system using the LoRa modulation scheme

open_access
Open Access
Author:
Stepko, Alexander
Area of Honors:
Electrical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
David Cubanski, Thesis Supervisor
Julio Urbina, Thesis Honors Advisor
Keywords:
wireless
rf
LoRa
lora
communications
real time operating system
RTOS
networking
mesh network
Abstract:
This work performs extensive study and exploration into the design, implementation, and testing of a wireless mesh communication system. The communication system employs the LoRa modulation scheme, a chirp spread spectrum (CSS) derivative that provides an extremely high link budget, in addition to built-in redundancy inherent in the symbol space. We begin the work via an introduction of network topologies observed in the wireless space and conduct a discussion on the critical factors and layers that must be considered when designing a mesh communication system. A system design is proposed, which includes application, network, and physical layers. Dynamic mesh topology establishment and maintenance is achieved without user intervention via implementation and abstraction of the distance vector routing (DVR) algorithm. We implement the proposed architecture on a dual-core Espressif ESP32-S3 microprocessor and a Semtech SX1262 sub-GHZ LoRa wireless transceiver module contained on a Heltec WiFi LoRa 32 (v3) development platform. Software is written in C with a multi-threaded architecture using FreeRTOS. Following system development, we present results that show the development of a mesh communication system using LoRa is not only feasible but fruitful in terms of spectral efficiency and immunity to noise in high-interference environments. Finally, we conclude with a discussion about the system's performance and explore further areas for system development.