Certified Wireless Network Administrator (CWNA)

Trace the evolution of wireless communications from 19th-century experiments by scientists like Tesla to aloha in Hawaii at 400 MHz and 1990s cordless phones at 900 MHz.

Explore how the ITU coordinates global spectrum management through regions such as Region A Americas with Sitel, Cept in Western Europe, and APT in the Asia Pacific.

Discover how the IETF uses the RFC process to turn ideas into standards and best practices. See how protocol standards and IP addressing concepts guide network design and internet operation.

Explore wireless communications fundamentals by examining modulation, radiofrequency, and how wavelength, amplitude, and frequency define data transmission and the peaks of a sine wave.

Explore how frequency describes the behavior of waves by counting how many waves occur per second from an antenna, and how the distance between peaks defines transmission frequency.

Explore keying methods used in wireless signaling, including amplitude shift keying (ASK), frequency shift keying (FSK), and phase shift keying schemes, and learn how receivers detect ones and zeros.

Explore wireless history and standards, from FCC, ITU-R, and IETF to OSI model’s access, distribution, and core layers. Understand how carrier signals carry ones and zeros from transmitter to receiver.

Map the spectrum from low to high frequency, define frequency as waves per second, and explain how amplitude and peak distance influence potential harm in various bands.

Understand how alternating current from a power source travels through a copper coax cable to an antenna and radiates an rf signal from an access point as a sine-wave waveform.

Demonstrate how wavelength relates to frequency through the speed of light, using lambda = c / f and c = 300,000,000 m/s, so higher frequency means a smaller wavelength.

Explore how frequency relates to time by analyzing peaks in a second-long window; higher frequency means more frequent events, while lower frequency shows fewer peaks.

Demonstrate how signals that are in phase amplify each other, and show that 90 degrees out of phase causes fewer problems, while 180 degrees out of phase cancels the signals.

Signals reflect off surfaces larger than the wave, creating multipath through delayed copies, including AM radio skywave and microwave reflections.

Explore how diffraction bends wireless signals around objects, unlike refraction through a medium, and examine practical implications for signal propagation around obstacles.

Explore multipath propagation in wifi networks and antenna spacing. See why early access points used two antennas about 4.2 inches apart to receive signals from reflections at different times.

Increase antenna power output by generating more transmitter power or by focusing the radiated signal; a focused beam boosts brightness, like a flashlight.

Explain how wifi rf power is measured in milliwatts, a thousandth of a watt, and note indoor 802.11 equipment typically transmits between 1 mW and 100 mW.

Learn that the decibel is a unit of comparison for power, showing how power changes from transmitter's antenna to the receiver's antenna, including free path loss and IPR or ERP.

Explains that the bell is defined as a 10-to-1 power ratio, illustrated by 100 mW transmitted and 10 mW received yielding one bell.

Learn how dBm measures power relative to a milliwatt using the formula 10 log10(power in milliwatts) and that zero dBm corresponds to a milliwatt, with 100 milliwatts equaling 20 dBm.

Apply rule of three and ten to power, showing how a 3 dBi gain doubles 100 mW to 200 mW, while a 3 dB loss halves it to 50 mW.

Explain the rules of tens and threes for dbm and milliwatts using a conversion table, illustrating doubling and halving, then apply to a wireless bridge with loss and gain.

Trace how to convert 50 mW to dB, apply a -1 dB loss and a +5 dB gain, and determine the resulting power to understand transmitter gains and coverage area.

RSSI illustrates how distance and interference affect wifi throughput; closer antennas reach higher speeds, while noise floors from microwaves reduce performance, underscoring the need to optimize antenna placement.

Explore the components of RF communications, understand units of power, and apply RF mathematics using the rule of tens and threes to get you in the ballpark.

Explore azimuth and elevation charts of antenna radiation envelopes, showing H plane top-down and E plane side views to visualize relative coverage patterns for omnidirectional and directional antennas.

Measure antenna beam width by locating the strongest point on a 360-degree chart and tracing to where the signal drops by minus 3 dB, yielding the beam width angle.

Explore the three main antenna types—omnidirectional, semi directional, and highly directional—and see how they shape site surveys and coverage decisions.

Explore how planar antennas provide targeted coverage for long hallways and rows of offices, using semi directional beams and appropriate beam width to optimize access points.

Discover the Yagi antenna for short to medium distance point-to-point links up to about two miles, with high gain, and how tilting it on a wall targets coverage between buildings.

Explore dynamic beam forming by steering RF energy with a center tower and multiple antennas, focusing the radiation pattern in shape and direction frame by frame to follow moving receivers.

Transmit beamforming sends many phase-shifted signals to arrive in phase at the presumed receiver, adjusting phase shifts and using polarization to improve the link.

Explore antenna polarization and how horizontal or vertical wave orientation affects signal strength; align transmitter and receiver to avoid polarization mismatch, especially for outdoor coverage.

Learn how antenna diversity uses two or more antennas to combat multipath, switching frames for the strongest signal and improving performance, a concept seen before the 802.11 standard.

Explore antennas, coverage concepts, and beamforming, including azimuth and elevation charts, and examine antenna arrays, Mimo, and transmit beamforming for multi-radio frequencies.

The lecture surveys the original IEEE 802.11 standards, detailing the physical layer and MAC sublayer, and contrasts infrared as a light-based medium with FHSS and DSS spread spectrum methods.

Explore 802.11a’s high-speed 5 GHz unlicensed operation, compare it with 2.4 GHz, and explain 100 MHz channel sizing and OFDM to boost data rates and adoption choices.

Explore 802.11i part2’s robust security network, emphasizing authentication, integrity, and confidentiality. See how access points and radius servers verify credentials and issue different encryption keys to different users under WPA.

Enables robust management frames in 802.11w, a task group w standard, to protect association and disassociation frames.

The 900 mhz ism band provides multiple 26 mhz channels from 902 to 928 mhz; GSM use in Europe limits it, while the United States used it for cordless phones.

explore the 5 ghz band, including 5.8 ghz with 150 mhz channels and 11 usable channels in the us, and why cordless devices share this spectrum as the junk band.

Explore 60 GHz wireless technology as a high-throughput, unlicensed-band solution with physical and mac layer enhancements, delivering up to seven gigabits per second for short indoor connections.

Compare narrow band and spread spectrum to understand how bandwidth shapes channel design and interference prevention, with FCC guidelines ensuring space between frequencies.

Explore the concept of frequency hopping with a predefined hopping sequence, and how both transmitter and receiver synchronize to move across channels for non-stop data flow.

Describe how dwell time dictates how long a system stays on a frequency before hopping in a frequency hopping spread spectrum, with FCC limits and 75 frequencies of 1 MHz.

Explain how direct sequence spread spectrum encodes data in the 2.4 GHz band, enabling 1–2 Mbps, 5.5 Mbps and 11 Mbps with high-rate DSS on a single channel.

Explain how OFDM uses BPSK and QPSK for lower data rates and 16-QAM and 64-QAM for higher rates, boosting speeds from 11 Mbps to 54 Mbps.

Explore how five gigahertz channels support 802.11a/n/ac, and how guard bands separate uni one and uni two, with 30 MHz spacing from band edges and 20 MHz in uni three.

Explore adjacent, nonadjacent, and overlapping channels in a wireless LAN. Design roaming-friendly cell coverage by using non-overlapping frequencies, such as channels 1, 6, and 11.

Explain how throughput relates to bandwidth and frequency band, distinguishing physical bandwidth from data bandwidth, and show how modulation and coding affect data rates, including Ofdm advantages.

Explore isms bands, uni narrowband spread spectrum, and frequency hopping, including dss and ofdm, on 2.4 and 5 gigahertz channels. Analyze adjacent, non-adjacent, and overlapping channels and throughput and bandwidth.

Explore the four major wireless topologies: wireless wide area network, wireless metropolitan area network, wireless personal area network, and wireless local area network, alongside other technologies like cellular, Bluetooth, and Zigbee.

Explore wireless local area networks (WLANs) that use access points to extend range and support multiple clients, ideal for home or office deployments with high throughput.

The distribution service channels data from the access point to its destination within basic or extended service sets. In deployments, the distribution system medium, DSM, is typically Ethernet.

Understand the basic service set (BSS), the simplest wireless topology with a single access point that connects multiple clients to a wired Ethernet network. Moving out of range disrupts connectivity.

Explore extended service sets that link two or more basic service sets via a distribution system medium, uniting access points and client stations; roaming can interrupt connections.

Ensure seamless roaming with a wireless LAN controller managing handoffs between access points, supported by overlapping coverage in the extended service set.

Explore how roaming between access points with co-location affects a user’s connection, requiring re-association and causing brief service disruption, including voice over IP calls.

Explore how access point modes enable long-distance wireless backhaul and network extension, including bridge, workgroup bridge, repeater, and mesh modes, with monitor mode for rogue point detection.

Explore the two client station modes in CWNA: infrastructure mode, where a computer connects to an access point, and ad hoc (independent service set) mode, enabling direct device-to-device data exchange.

Review wireless networking topologies, covering eight to eleven options, and examine the configuration modes for different access points.

Compare collision avoidance and collision detection in wireless and wired networks, highlighting half duplex limits and how CSMA/CA and CSMA/CD use media access control to manage access.

Explain how an access point coordinates half-duplex wireless communication using carrier sense, multiple access, and collision avoidance to grant permission before data transfer.

The distributed coordination function is the fundamental and mandatory access method for 802.11 communications, with optional methods like PCF and the hybrid coordination function (HCF).

Explore the distributed coordination function components, including carrier sense, physical and virtual listening, duration/ID fields, interframe spaces, backoff timers, and sifs/difs to minimize collisions on a half duplex medium.

Explain interframe space and its six types, highlighting reduced interframe space for QoS, SIFS, PCF interframe space, DIFS, arbitration interframe space, and extended interframe space for corrupted frames.

Explain how the duration id field signals the time in microseconds required for a unicast frame exchange (0 to 32,767 μs), during which other radios defer and hear the transmission.

Explore block acknowledgement requests that allow aggregating acknowledgements for multiple frames, improving efficiency, with immediate block acks for low latency traffic and delayed block acks for file transfers.

Explore the data link layer and its two sublayers: the logical link control (LLC) that interfaces with layer three, and the MAC address sublayer that handles media access.

Explore how control frames within 802.11 manage power saver signaling, clear to send, and block acknowledgments, while contrasting DCF, PCF, and HCF for contention-free, QoS-enabled frames.

Examine data frame subtypes, including data, null data, acknowledgments, and polls, plus PCF control frames, and how quality of service boosts efficiency and access-point preference.

Analyze beacon frames to understand time synchronization via the timestamp, supported data rates (basic and mandatory), channel, SSID, TIM for power saving, and security plus vendor-specific beacon fields.

Learn how authentication and association enable devices to connect to an access point and begin sending traffic to the wired network.