816  Mobile Wireless: Labs and Implementation

816.1 Learning Objectives

By the end of these labs and implementation chapters, you will be able to:

  • Run an RF site survey: Use Wi-Fi scanners (and optional SDR tools) to identify interference and congestion
  • Select optimal Wi-Fi channels: Choose non-overlapping channels and justify a channel plan from measurements
  • Implement an ESP32 scanner: Build simple tools to inventory nearby networks and visualize channel occupancy
  • Measure signal quality: Collect RSSI vs distance data and explain deviations from theoretical path loss
  • Bring up a cellular modem: Connect a modem to a microcontroller and validate registration using key AT commands
  • Document findings: Produce a short site-survey report with recommendations (channels, placement, and risks)

816.2 Prerequisites

Before diving into these chapters, you should be familiar with:

  • Mobile Wireless: Fundamentals: Understanding electromagnetic waves, frequency bands, path loss calculations, and spectrum allocation is essential for interpreting lab results
  • Mobile Wireless Technologies Basics: Knowledge of wireless communication principles, frequency characteristics, and propagation models provides the theoretical foundation for practical measurements
  • Networking Basics for IoT: Basic networking concepts help in understanding how wireless technologies integrate into larger IoT systems
  • Basic programming skills: Familiarity with Python and C++ (Arduino/ESP32) is needed to implement the lab exercises and analyze data

Deep Dives: - Cellular IoT Fundamentals - LTE-M and NB-IoT deep dive - LoRaWAN Overview - Sub-GHz LPWAN alternative - Wi-Fi Fundamentals - High-bandwidth wireless option

Comparisons: - Mobile Wireless Comprehensive Review - Technology comparison matrix - LPWAN Comparison - Range vs power trade-offs

Hands-On: - Simulations Hub - RF propagation simulators

Learning: - Quizzes Hub - Test mobile wireless knowledge

816.3 Getting Started (For Beginners)

These labs are about making the RF concepts from the fundamentals chapters visible in the real world.

  • If you have an ESP32 and can install tools:
    • Run the Wi-Fi scanner, collect RSSI measurements at different locations, and build a simple channel plan.
    • Use the exercises to connect what you see on the screen with ideas like channel congestion and path loss.
  • If you also have a cellular modem module:
    • Do the AT command smoke test (power, SIM readiness, registration, signal quality) before writing firmware.
  • If you cannot run the code right now:
    • Read through the sketches and focus on the printed outputs and analysis questions.
    • Sketch simple “coverage maps” on paper based on the example outputs, then answer the Knowledge Check.

Key ideas to remember while working through these chapters:

Concept Plain explanation
Channel A slice of spectrum; multiple Wi-Fi networks share it
RSSI Received signal strength indicator (how loud the AP is)
Interference Other devices transmitting on the same/adjacent channel
Path loss How much signal power is lost as distance increases

If terms like RSSI, path loss, or channel overlap feel unfamiliar, skim mobile-wireless-fundamentals.qmd and mobile-wireless-technologies-basics.qmd again, then come back and treat these labs as concrete experiments that bring those graphs and formulas to life.

816.4 Chapter Overview

This content has been organized into three focused chapters for easier navigation and deeper coverage of each topic:

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flowchart LR
    subgraph LABS["Mobile Wireless Labs"]
        MODEM["Cellular Modem<br/>Integration"]
        WIFI["Wi-Fi Spectrum<br/>Analysis"]
        COVERAGE["Coverage<br/>Planning"]
    end

    MODEM --> WIFI
    WIFI --> COVERAGE
    MODEM -.-> COVERAGE

    style MODEM fill:#E67E22,stroke:#2C3E50,color:#fff
    style WIFI fill:#16A085,stroke:#2C3E50,color:#fff
    style COVERAGE fill:#2C3E50,stroke:#16A085,color:#fff

Figure 816.1

816.4.1 1. Cellular Modem Integration

Focus: AT commands and cellular modem bring-up

Topics covered:

  • Cellular modem architecture and integration patterns
  • AT command communication flow and sequence diagrams
  • Modem bring-up checklist (power, SIM, registration, signal)
  • Troubleshooting common modem issues
  • Sample Arduino code for modem initialization

Best for: Getting started with cellular IoT hardware, understanding the AT command interface, and systematic modem debugging.

816.4.2 2. Wi-Fi Spectrum Analysis

Focus: ESP32 scanning and RF site surveys

Topics covered:

  • Wi-Fi channel scanner implementation
  • Understanding 2.4 GHz channel overlap (why 1/6/11)
  • Signal strength mapping across locations
  • Path loss measurements vs theoretical values
  • Site survey report template and methodology

Best for: Running practical RF assessments, understanding channel congestion, and creating deployment recommendations.

816.4.3 3. Coverage Planning

Focus: Python tools for deployment planning

Topics covered:

  • Electromagnetic wave property calculations
  • Link budget analysis for IoT deployments
  • ESP32 real-time spectrum monitor with web interface
  • RF coverage planner with RSSI heatmaps
  • Dead zone identification and AP placement optimization

Best for: Pre-deployment planning, quantitative link analysis, and building monitoring tools.

816.6 Quick Reference: Key Concepts

Concept Chapter Description
AT Commands Cellular Modem Text commands for modem control
CREG/CEREG Cellular Modem Network registration status
Channel 1/6/11 Wi-Fi Spectrum Non-overlapping 2.4 GHz channels
RSSI Wi-Fi Spectrum Received signal strength indicator
Path Loss Coverage Planning Signal attenuation with distance
Link Budget Coverage Planning TX power to RX sensitivity analysis
Fresnel Zone Coverage Planning RF clearance requirements

816.7 Summary

This chapter series provides hands-on experience with wireless network analysis and implementation:

  • Cellular modem bring-up connects the concepts to practice: power, UART, SIM readiness, and network registration using AT commands
  • Wi-Fi channel scanning turns spectrum congestion into actionable channel plans (1/6/11) for 2.4 GHz deployments
  • Path loss measurements highlight real-world deviations from theoretical models due to obstacles, multipath, and interference
  • Link budget sanity checks help you decide quickly whether a deployment is viable (or needs a different band/topology)
  • Spectrum monitoring enables longer-term logging and reporting to catch time-of-day interference patterns
  • Coverage planning helps visualize RSSI heatmaps and dead zones to guide placement and upgrades

816.8 What’s Next

With practical RF analysis skills established, continue your wireless IoT journey with: