Smart Building Management with IoT Sensors 2026

Evaluating LoRaWAN coverage in sub-ground level spaces, e.g. basements

Name GroupNo Thing DevEUI Sensor ObservedProperty LppChannelNr FROST Datastream IDs
Guang Yang 
17
 
17.GY FROST Test
 TTN: 
8765182202E81E20
 
BME680 v1.0
 
Temperature[°C]
 
1
 
1732
Cheng Jhe 17



1 1765

Contents

1. Introduction

1.1. Background: IoT and LoRaWAN in Smart Cities

Internet of Things (IoT) technologies play as one of the most essential applications in Smart City and Building ideas aiming to collect data from various aspects of systems and respond accordingly. For example, monitoring energy consumption, operating a smart waste management system, monitoring, and tracking traffic, having smart parking systems, monitoring public lighting, and even detecting various malfunctions.

Among them, LoRaWAN technology, as a branch of LPWAN technology, when compared with Sigfox and NB-IoT, LoRaWAN has gained popularity as the most widely adopted non-cellular technology for distributed IoT applications due to its comprehensive advantages such as supporting private network deployment, medium transmission distance, strong anti-interference capability, communication encryption, built-in positioning function, and the lowest usage cost. It is particularly suitable for small-scale data applications with continuous transmission but long intervals, such as remote metering of water, electricity, and gas, which precisely meets the core requirements of infrastructure monitoring in smart cities.

LoRaWAN products can be certified by functions:

  • module
  • development board
  • sensor node
  • actuator node
  • sensor interface unit
  • meter interface unit
  • tracker
  • tester
1.2. The Challenge of Sub-Ground Coverage

The LoRaWAN end-devices can be classified into two groups based on the deployment environment: indoor/outdoor and fixed/mobile. The smart building monitoring scenario that this project focuses on falls under the category of fixed installation and indoor/underground deployment. The actual performance of LoRaWAN devices is influenced by various factors. They are relatively insensitive to external disturbances and environmental factors, but outdoor devices still need to consider physical protection. Device movement significantly affects radio parameters, that is why fixed deployment is relatively stable. The selection and installation method of antennas are one of the key variables determining transmission performance.

Although LoRaWAN performs well in open areas on the ground, when the application scenarios extend to underground spaces such as basements, subway stations, and underground parking lots, signal transmission will face challenges that are not present in the ground environment: 

  • Strong signal attenuation caused by building structures
  • Gateway location is not visible
  • The influence of antenna pattern and polarization direction is magnified
  • Failure of auxiliary positioning methods such as GPS
  • Some secondary impacts of environmental factors, such as humidity and temperature fluctuations
1.3. Key Concepts
1.3.1. LoRa Modulation and LoRaWAN Protocol
1.3.2. Transmission Parameters: RSSI, SNR, SF, Packet Loss
1.3.3. Antenna Fundamentals: Gain, Directionality, Polarization
1.4. Research Questions and Objectives


1.5. Group Members and Task Distribution


2. System Setup

2.1. Hardware Node Architecture
2.2. Seeeduino LoRaWAN+GPS


LCD Display "Hello World" example 
#include <Wire.h>
#include "rgb_lcd.h"
#define PIN_GROVE_POWER 38

rgb_lcd lcd;

void setup() {
  // Powerup Seeeduino LoRaWAN Grove connectors
  pinMode(PIN_GROVE_POWER, OUTPUT);
  digitalWrite(PIN_GROVE_POWER, 1);
  // set up the LCD's number of columns and rows:
  lcd.begin(16, 2);
  // Print a message to the LCD.
  lcd.print("Hello World");
}

void loop() {
  // Turn off the display:
  lcd.noDisplay();
  delay(500);
  // Turn on the display:
  lcd.display();
  delay(500);
}

2.3. BME680 — Temperature, Humidity, Pressure and Gas Sensor


BME680 Test 
#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_BME680.h>

#define SEALEVELPRESSURE_HPA (1013.25)

Adafruit_BME680 bme;

void setup() {
  Serial.begin(9600);
  while (!Serial);

  Serial.println("BME680 test");

  if (!bme.begin(0x76)) {
    Serial.println("Could not find a valid BME680 sensor at 0x76");
    while (1);
  }

  bme.setTemperatureOversampling(BME680_OS_8X);
  bme.setHumidityOversampling(BME680_OS_2X);
  bme.setPressureOversampling(BME680_OS_4X);
  bme.setIIRFilterSize(BME680_FILTER_SIZE_3);
  bme.setGasHeater(320, 150);
}

void loop() {
  if (!bme.performReading()) {
    Serial.println("Failed to perform reading");
    return;
  }

  Serial.print("Temperature: ");
  Serial.print(bme.temperature);
  Serial.println(" C");

  Serial.print("Humidity: ");
  Serial.print(bme.humidity);
  Serial.println(" %");

  Serial.print("Pressure: ");
  Serial.print(bme.pressure / 100.0);
  Serial.println(" hPa");

  Serial.print("Gas: ");
  Serial.print(bme.gas_resistance / 1000.0);
  Serial.println(" KOhms");

  Serial.println();
  delay(2000);
}

2.4. Grove GPS (Air530)


2.5. The Things Network (TTN)


2.6. LoRaWAN Antennas


3. Experimental Design

3.1. Research Questions Revisited


3.2. Site Selection


3.2.1. Criteria for Selecting Test Sites
3.2.2. Description of Selected Basement Locations
3.2.3. Surface-Level Reference Site
3.3. Experimental Matrix: Sites × Antennas × Orientations


3.4. Standard Operating Procedure (SOP)


3.5. Data Recording Template


4. Experiments and Results

4.1. Baseline Measurements (Surface Level)


4.2. Sub-Ground Coverage Tests
4.2.1. Site A — Shallow Basement
4.2.2. Site B — Deep Basement
4.2.3. Site C — Special Structure
4.2.4. Cross-Site Comparison
4.3. Antenna Orientation and Polarization Tests


5. Data Analysis

6. Conclusion and Outlook

7. References

8. Appendix

8.1. Full Source Code
8.2. Raw Data Tables
8.3. Additional Photos
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