WiFi Fundamentals

Explore RF waves for Wi-Fi, focusing on sine waves, attenuation, and RF loss, and learn how different frequencies and the access point interact to help plan a network more effectively.

Relate RF energy to the sine wave and identify its key properties—period, frequency, wavelength, amplitude, and phase—while linking circle geometry to phase.

Explore RF properties—period, wavelength, frequency, amplitude, and phase—and how interference and energy loss through free space shape WiFi signals between an access point and station.

Explore RF loss in wifi networks, including freespace path loss, multipath from obstacles, and interferences, and see how distance, inverse square law, receiver sensitivity, and frequency affect data rate.

Explore RF loss part 2 by examining reflection, absorption, kettering, and refraction, and how frames, RSSI, and SNR relate to dBm to manage signal paths.

Explore how decibels and dBm express relative power in Wi-Fi, learn the six dB rules, and apply concepts of antenna gain, cable loss, and reference zero.

Master the basics of dBm and decibels in wifi networks, analyzing transmitter power, loss, signal-to-noise ratio, and antenna gain, including how 6 dBi doubles coverage and the 3 dB rule.

Discover how antennas influence wireless performance through directional and omni directional patterns, and how frequency, wavelength, and antenna length determine resonance and coverage.

Explore the tropic antenna model and directional antennas, and define gain as directional power relative to the tropic reference, noting main, back, and side lobes.

Explore antenna directivity and polarization, linking beam shape to gain and how environment affects signal paths. Learn how the electric field determines polarization and why device orientation matters.

Explore antenna types, calculate effective power (ERP), analyze beam patterns, and understand how high gain and directional antennas shape coverage and security implications in wifi networks.

Learn the basic wifi connection process, including passive beacon discovery and active probe requests, to identify access points, SSIDs, channels, data rates, and security like WPA two and Shanno.

Explore how a station moves from discovery to authentication and association, joining an access point through probe requests and association responses, with security checks and state transitions.

Explore how the MAC layer coordinates access to the shared air interface, enabling beacon frames, probe requests, and frame retransmissions to connect stations with access points.

Explore how the Wi-Fi physical layer handles transmission and reception of frames, modulation, channel selection, and interference avoidance, with data rate tied to distance and signal conditions.

Understand how wireless air is shared using csma-ca, with physical and virtual carrier sensing, nav duration values, and backoff contention windows to avoid collisions and ensure fair access.

Explore csma-ca part 2 and how the dcf coordinates wireless transmissions by waiting intervals like dfs and siac fast, using carrier sensing and backoff timers to resolve contention.

Understand how 2.4 ghz and 5 ghz wifi bands shape network performance, including 20 mhz channels, non-overlapping layouts, and the shift from dss to ofdm with dfs in 5 ghz.

Explore why the 2.4 ghz band is narrow and crowded, causing co-channel and adjacent channel interference when access points share channels, and learn to plan channels with adequate separation.

Explore the five gigahertz band, delivering faster data rates over shorter distances, with wider channel options, bonding up to 160 megahertz, and considerations for interference, radar, and power management.

Explore wifi frames, including beacon frames, and use Wireshark to analyze traffic and troubleshoot networks in promiscuous mode. Learn the three frame types—management, control, and data—and their headers and payloads.

Learn to analyze frames in Wireshark by filtering management frames with subtype 5, and observe frame subfields, including destination, transmitter, and source addresses and sequence numbers.

Analyze the WiFi frame control field, its 11 subfields, and how type, subtype, and ds bits determine frame direction, fragmentation, retry, power management, protection, and data ordering.

Explore wifi frame types, focusing on management frames that establish and maintain connections, and the role of probe requests, authentication, association, and deauthentication in the process.

Learn how rts/cts regulate wifi traffic to keep the air quiet. Examine duration values and nav timers in hidden station and hidden access point scenarios.

Explore how radio signals propagate through ground wave, skywave, and line-of-sight paths, how atmosphere layers and conditions affect attenuation, and how received power compares to transmitted power.

Explore how free-space path loss affects wifi ranging, showing how distance and frequency shape received power from 2.4 GHz and 5 GHz access points via the inverse square law.

Analyze free-space path loss for a 2.4 gigahertz wifi link over one meter, incorporating transmitter power, antenna gain, and path loss to estimate received power and RSSI.

Analyze how RSSI measures RF energy at the antenna and how the inverse square law causes signal power to decay with distance, influencing modulation and connection speed.

Explore rssi-based distance estimation using the inverse square law, fingerprinting, and real-time measurements. Apply occupancy sensing with multiple access points, site surveys, and frequency- and interference-aware conditions.

Explore wifi fundamentals with the RSSI equation: compare free-space path loss from received power to a 1-meter reference and a radio map approach, noting multipath challenges.

Collect RSSI fingerprints by surveying a room with three access points and mapping grid points. Record RSSI values to build a radio map for location estimation.

The k nearest neighbors algorithm classifies unknown data by majority vote from the training set using feature similarity, aiding wifi network planning and site survey fingerprint readings.

Learn time of arrival ranging in wifi fundamentals, using propagation time and speed of light to compute distance, with nanosecond clock synchronization and one-way versus two-way ranging for robust positioning.

Use distance estimates from access points via freespace path loss and RSSI-based radio map to locate a station. Plot circles from those distances and intersect to pinpoint position.

Learn how to locate a fire station using circles centered at known points with fixed distances, and refine the position by intersecting multiple circles.