The Wireless Glossary

320 MHz Channels

Wi-Fi 7's headline party trick: channel widths doubled to 320 MHz, only possible in the 6 GHz band. That's a firehose of throughput for a single client, but in the real world you get maybe one or two clean 320-wide channels, so in high-density deployments I'm still designing around 40 and 80. Great for a point-to-point bridge or a lab demo; think hard before you flip it on in an enterprise.

4096-QAM

The modulation scheme in Wi-Fi 7 that packs 12 bits into every symbol instead of the 10 you got with Wi-Fi 6's 1024-QAM — roughly a 20% data-rate bump. The catch is it demands a nearly perfect signal, so you'll only see it when the client is close to the AP with a fat SNR. It's a front-row-seats feature, not a back-of-the-venue feature.

6 GHz LPI / VLP / SP

The three power classes for 6 GHz Wi-Fi. LPI (Low Power Indoor) is your standard indoor AP — no AFC needed, but keep it inside. VLP (Very Low Power) is for portable, short-range stuff like AR glasses and hotspots. SP (Standard Power) lets you run higher EIRP and go outdoors, but you have to check in with an AFC system first so you don't stomp on the incumbents.

Adjacent-Channel Interference

Interference from radios on overlapping or neighboring channels — and it's nastier than co-channel because the radios can't decode each other, so they just see noise and talk over it. This is the classic 2.4 GHz sin of putting APs on channels 1, 4, 8, and 11. Stick to non-overlapping channels; noise you can't demodulate is worse than a neighbor you can politely defer to.

AFC (Automated Frequency Coordination)

The database-driven traffic cop for standard-power 6 GHz Wi-Fi. Before an SP access point transmits, it tells the AFC where it is, and the AFC tells it which frequencies and power levels won't interfere with incumbent fixed microwave links. It's the same playbook as CBRS and the SAS — spectrum sharing by database instead of by lawsuit — and it's what unlocks outdoor 6 GHz.

Airtime Fairness

A scheduling feature that divides up airtime instead of packet counts, so one slow legacy client can't hog the channel while fast clients wait. Remember: Wi-Fi is a shared medium, and a device transmitting at 6 Mbps takes forever to say what an ax client says in a millisecond. Airtime fairness keeps that one ancient barcode scanner from tanking the whole cell.

AP-on-a-Stick

The old-school validation method: mount an actual AP on a tripod at the proposed height, walk the area, and measure what real RF does in that real building. Predictive surveys guess; APoS proves. When there's real money or a real deadline riding on coverage — a stadium bowl, a warehouse full of steel racking — you put the AP on the stick.

Attenuation

Signal loss as RF passes through stuff — drywall, glass, concrete, humans, that decorative water feature the architect loved. Measured in dB, and every material has its own toll. Most "Wi-Fi is broken" tickets are really attenuation problems: the design didn't account for what's actually between the AP and the client.

Backhaul

The pipe that carries traffic from your access layer back to the network core and out to the internet. Your Wi-Fi is only ever as good as its backhaul — a beautiful AP deployment feeding into a congested link is a sports car on a dirt road. Fiber if you can get it, licensed or well-engineered wireless if you can't.

Band Steering

An AP-side nudge that encourages dual-band clients off crowded 2.4 GHz and onto 5 or 6 GHz. It works by playing a little hard-to-get — delaying or withholding probe responses on 2.4. Useful, but remember the client always makes the final call on where it connects; steering is a suggestion, not a command.

Beamforming

The AP shaping its transmission — adjusting phase across multiple antennas — so energy concentrates toward a specific client instead of spraying in all directions. Better signal at the client means higher data rates and less airtime burned. It's built into modern standards and mostly just works; you don't tune it, but it's why multi-antenna APs earn their money.

BSS Coloring

A Wi-Fi 6 feature that tags each network's frames with a "color" so a radio can tell my traffic from the neighbor's. If it hears a different color at low signal strength, it can transmit anyway instead of politely waiting. In dense deployments — apartments, stadiums, conference floors — that's real reclaimed airtime, because half of Wi-Fi's problems are radios being too courteous.

Captive Portal

The splash page that intercepts a guest before they get internet — accept terms, enter an email, maybe watch a sponsor logo. It's part access control, part marketing tool, and if you're doing large venues it's often where the Wi-Fi actually pays for itself. Just keep it fast and don't make people log in twice; nobody at a festival has patience for a broken portal.

CBRS (Citizens Broadband Radio Service)

150 MHz of shared spectrum at 3.55–3.7 GHz that lets regular folks run LTE and 5G without buying a carrier license. A SAS database coordinates three tiers — incumbents, PAL licensees, and GAA users — so everybody shares without stepping on the Navy's radar. We used it to blanket McAllen, Texas with citywide connectivity in 60 days; it's the most democratizing thing to happen to spectrum in decades.

Channel Reuse

The art of assigning the same channel to multiple APs far enough apart that they don't hear each other. You've only got so many channels, so reuse distance is what determines how dense you can build. This is where narrower channels earn their keep: 20 MHz channels give you more colors to paint with, which matters way more in high density than raw per-channel speed.

Co-Channel Interference

What happens when APs on the same channel can hear each other: they take turns, because Wi-Fi is polite. It's technically contention, not interference — nothing gets corrupted, everything just gets slower. It's also the number one self-inflicted wound in Wi-Fi design, usually caused by too many APs cranked to full power.

Co-SR (Coordinated Spatial Reuse)

A Wi-Fi 8 / MAPC technique where neighboring APs coordinate their transmit power so they can talk at the same time on the same channel without wrecking each other. Instead of one AP blasting and everyone else waiting, they agree to talk quieter and simultaneously. It's BSS coloring's smarter sibling — cooperation by plan instead of by threshold.

Co-TDMA (Coordinated Time Division Multiple Access)

Another MAPC tool in Wi-Fi 8: an AP that wins the channel can share slices of its transmit window with neighboring APs. Think of it as scheduled turn-taking between access points instead of the free-for-all of pure contention. For dense enterprise and venue deployments, this is Wi-Fi finally borrowing the discipline that made cellular work.

Controller vs. Cloud-Managed

The old model puts a hardware controller on-site to manage your APs; the modern model puts the management plane in the cloud with APs forwarding traffic locally. Cloud wins on ops simplicity, licensing wins on nobody's favorite spreadsheet. My take after twenty-plus years: the architecture matters less than whether your team can actually see and fix problems fast — pick the one your people will really use.

dBm

Decibels referenced to one milliwatt — the logarithmic unit we use for RF power, where 0 dBm is 1 mW and every 3 dB doubles or halves it. Received Wi-Fi signals live in negative territory: -50 dBm is loud and clear, -80 dBm is whispering across a canyon. Get comfortable with log math; it's the native language of everything else in this glossary.

DFS (Dynamic Frequency Selection)

The rule that lets Wi-Fi use radar-shared 5 GHz channels — as long as the AP listens first, and vacates the channel immediately if it detects radar. That vacate event kicks every client off with no warning, which is why some deployers avoid DFS channels entirely. Near airports and coastlines, test before you trust; everywhere else, that's a lot of clean spectrum going to waste.

EIRP (Effective Isotropic Radiated Power)

The total power actually leaving the antenna in its strongest direction: transmitter power plus antenna gain minus cable loss. It's the number regulators care about, and it's the number you get fined over. Cranking a radio to max and bolting on a high-gain antenna can put you over the legal limit fast — do the math before you key up.

Fixed Wireless Access (FWA)

Broadband delivered over radio to a fixed location — an antenna on the house talking to a base station on a tower — instead of trenching fiber or coax. It's how WISPs have connected rural America for decades, and now the big carriers do it over 5G. When the trench costs more than the customer will ever pay, FWA is the answer.

GAA (General Authorized Access)

The free tier of CBRS: no license, no auction, just register your radios with a SAS and use whatever spectrum the incumbents and PAL holders aren't. It's opportunistic, so you can get moved or squeezed, but for most private networks GAA is plenty. The McAllen citywide build ran on it — free spectrum, real results.

Heat Map

The color-coded coverage visualization every stakeholder loves — green is good, red is bad, and everyone nods. Just remember a heat map is only as honest as the data behind it: a predictive map is a model, a validation map is a measurement, and they are not the same document. Green wallpaper doesn't move packets; verify it.

Hidden Node

Two clients that can both hear the AP but can't hear each other, so they transmit simultaneously and their frames collide at the AP. Classic in long, narrow spaces and outdoor deployments where clients sit on opposite edges of a cell. RTS/CTS can mitigate it, but the real fix is designing cells so clients within them can actually hear one another.

LEO Satellite Backhaul

Using low-earth-orbit constellations — Starlink being the obvious one — as the upstream pipe for a network where fiber and fixed wireless can't reach. Latency in the 25–60 ms range makes it genuinely usable, which changed the game for disaster response, remote events, and rural builds. I've fed whole event networks off a dish you can carry in one hand; five years ago that was science fiction.

MAPC (Multi-AP Coordination)

The big idea in Wi-Fi 8: access points stop acting like strangers shouting in the same room and start coordinating — sharing time slots (Co-TDMA), coordinating power (Co-SR), even beamforming cooperatively. Every AP today is an island; MAPC makes them a team. For those of us who design dense networks for a living, this is the most important thing in the 802.11bn spec.

Mesh

APs that use their own radios to backhaul traffic to each other instead of each having a wire. Every wireless hop costs you roughly half your throughput and adds latency, so mesh is a tool for places you truly can't cable — not an excuse to skip the cabling budget. One or two hops, dedicated backhaul radio, and know when to run the wire anyway.

MLO (Multi-Link Operation)

The Wi-Fi 7 feature that lets a client use multiple bands — say 5 and 6 GHz — simultaneously as one logical connection. That means aggregated throughput, and more importantly, the ability to dodge interference on one link without dropping the session. For latency-sensitive stuff like AR and industrial control, MLO is the real Wi-Fi 7 story, not the giant channel widths.

MU-MIMO (Multi-User MIMO)

An AP using its multiple antennas to transmit to several clients at literally the same time, spatially separating the streams. Sounds magical, and it is — when clients cooperate, hold still, and are positioned favorably, which in the field is less often than the datasheet implies. It helps in dense downlink-heavy environments; OFDMA does more of the real everyday work.

NaaS (Network as a Service)

Buying your network as a subscription — hardware, management, lifecycle, sometimes the whole operation — instead of a capital purchase you sweat for seven years. It shifts networking from capex to opex and puts the refresh burden on the vendor. For lean IT shops and multi-site operators it makes real sense; just read the exit clauses like your business depends on them, because it does.

Network Slicing

A 5G capability that carves one physical network into multiple virtual networks, each with its own guaranteed performance characteristics — one slice for push-to-talk, one for cameras, one for guest data. It's QoS with actual teeth, enforced end to end. In private 5G, slicing is how you promise the robots their latency while the break-room tablets stream video.

OFDMA (Orthogonal Frequency Division Multiple Access)

The Wi-Fi 6 feature that carves a channel into smaller frequency chunks so an AP can serve multiple clients in a single transmission, instead of one client hogging the whole channel per turn. Borrowed straight from LTE, and it's the single biggest reason Wi-Fi 6 handles density better than everything before it. Less about peak speed, all about efficiency when the room fills up.

PAL (Priority Access License)

The paid middle tier of CBRS: a 10 MHz county-level license, bought at auction, that gives you priority over GAA users but still yields to incumbents. If your business can't tolerate getting bumped — think utilities, carriers, industrial operations — a PAL buys you predictability. Everybody else does just fine on GAA.

Passpoint / OpenRoaming

The tech that makes Wi-Fi work like cellular: your device authenticates automatically and securely to any participating network with no portal, no password, no thinking. Passpoint (Hotspot 2.0) is the standard; OpenRoaming is the federation that lets identities roam between providers worldwide. This is how public Wi-Fi should have worked all along, and it's finally happening.

PMF (Protected Management Frames)

Encryption for the management traffic — deauth, disassociation — that used to fly around in the clear, which is what made deauth attacks and cheap "Wi-Fi jammers" possible. WPA3 makes PMF mandatory, closing a hole that was embarrassing for about fifteen years. If a client can't do PMF in 2026, it's time for that client to retire.

PoE (802.3af/at/bt)

Power over Ethernet — one cable for data and power, which is why we can hang APs and cameras anywhere there's a ceiling. 802.3af gives you 15.4W, 802.3at (PoE+) 30W, and 802.3bt up to 90W. Modern Wi-Fi 6E/7 APs increasingly want .bt to run all radios at full tilt, so check your switch budget before your shiny new APs quietly disable a radio.

Point-to-Multipoint (PtMP)

One base station serving many client radios across a sector — the architecture behind every WISP and most CBRS deployments. Capacity is shared, so your sector design and subscriber loading math matter more than the datasheet peak. It's how you cover a neighborhood, a ranch, or a whole city from a handful of towers.

Point-to-Point (PtP)

A dedicated wireless link between exactly two radios — building to building, tower to tower. With clear line of sight and proper engineering (Fresnel zone clearance, link budget, licensed spectrum if it's critical), a PtP link can move multiple gigabits reliably for miles. It's fiber speed without the trenching permit.

Preamble Puncturing

A Wi-Fi 7 trick that lets an AP use a wide channel even when part of it is occupied — it just "punctures" out the dirty 20 MHz slice and transmits around it. Before this, one interferer in the middle of your 160 MHz channel meant abandoning the whole width. It's spectrum triage, and it makes wide channels actually survivable in the real world.

Predictive Survey

A software-modeled Wi-Fi design built from floor plans, wall materials, and AP specs before anyone hangs hardware. It's an educated guess — a good one if the inputs are honest, a fantasy if someone drew every wall as drywall. Use it to budget and plan, then validate with real measurements, because the model has never met your building's surprise concrete.

Private LTE / 5G

Your own cellular network — your radios, your core, your SIMs — typically on CBRS spectrum in the US. It gives you what Wi-Fi struggles with: predictable handoffs at speed, long range per radio, SIM-based security, and coverage economics that shine outdoors and in big industrial spaces. It's not a Wi-Fi replacement; it's the other tool in the box, and smart operators run both.

QoS / WMM

Quality of Service for Wi-Fi, implemented as WMM's four access categories — voice, video, best effort, background — where higher-priority traffic statistically wins the race for airtime. It's probabilistic, not guaranteed, which is why a saturated channel still ruins your voice calls. QoS markings only matter if they're honored end to end, so check your wired side too.

Resource Unit (RU)

The individual slice of channel that OFDMA hands to a client — as small as 26 subcarriers, about 2 MHz worth. Instead of a client getting the whole 80 MHz channel to send a tiny packet, it gets an RU sized to the job while other clients use the rest. Think of it as splitting one wide highway lane into a bunch of narrow ones so the scooters stop blocking the trucks.

Roaming (802.11k/v/r)

The trio that makes moving between APs not terrible: 11k gives clients a neighbor report so they know where to go, 11v lets the network suggest a move, and 11r makes the re-authentication fast enough that a voice call survives it. Roaming is always the client's decision — k/v/r just gives it better information and a faster handshake. If voice over Wi-Fi matters to you, these aren't optional.

RSSI (Received Signal Strength Indicator)

How loud the signal is at the receiver, expressed in dBm — the first number everyone checks and the one people over-trust. A -60 dBm signal sounds great until you learn the noise floor is -70. RSSI without SNR is half a diagnosis; strong and noisy loses to moderate and clean every time.

SAS (Spectrum Access System)

The cloud-based coordinator that makes CBRS work: every radio registers with a SAS, which assigns frequencies and power levels so incumbents, PAL holders, and GAA users coexist without collisions. Google and Federated are the big operators. It proved spectrum could be shared by database at scale — and AFC in 6 GHz is the direct descendant of that proof.

SNR (Signal-to-Noise Ratio)

The gap, in dB, between your signal and the noise floor — and it's the number that actually determines your data rate. High-order modulation like 1024- and 4096-QAM needs a big SNR; without it, the radios downshift no matter how strong the RSSI looks. Design for SNR, not just signal strength, and half your throughput complaints disappear.

Spectral Efficiency

How many bits per second you squeeze out of each hertz of spectrum — the true scoreboard of wireless engineering. Spectrum is finite; efficiency is how the industry keeps delivering more without more spectrum. Almost every feature in this glossary — OFDMA, MU-MIMO, 4096-QAM, MAPC — is really just another attempt to raise this one number.

Spectrum Analysis

Looking at raw RF energy instead of just Wi-Fi frames, so you can see the non-Wi-Fi interferers — microwave ovens, wireless cameras, baby monitors, that mystery transmitter on the roof — that packet captures are blind to. When a network misbehaves and the Wi-Fi tools show nothing wrong, the spectrum analyzer finds the culprit. Every serious deployer needs one and needs to know how to read a waterfall.

SSID (Service Set Identifier)

The network name your devices see — and every one you broadcast costs airtime in beacon and management overhead across every AP, every channel, forever. The rookie move is an SSID per department; the pro move is a few SSIDs with VLANs and policy doing the segmentation behind the scenes. Keep it under four if you can.

TWT / R-TWT (Target Wake Time / Restricted TWT)

TWT, from Wi-Fi 6, lets a client and AP schedule exactly when the client wakes up to talk — huge for IoT battery life. R-TWT, in Wi-Fi 7, flips it into a latency tool: protected service windows where only designated traffic transmits, giving time-critical applications a reserved slot. It's the closest Wi-Fi has come to deterministic scheduling, and industrial deployments should be paying attention.

VLAN (Virtual LAN)

Logical segmentation of one physical network into isolated broadcast domains — guest traffic here, cameras there, corporate over there, all on the same switches and APs. In wireless, VLANs are how a handful of SSIDs (or one, with dynamic assignment) serves a dozen security postures. Segmentation is the cheapest security you'll ever deploy; use it.

Wi-Fi 6 (802.11ax)

The generation that stopped chasing peak speed and started chasing efficiency: OFDMA, TWT, BSS coloring, 1024-QAM. One-line difference: Wi-Fi 6 is about serving lots of clients well, not one client fast. It's why a packed stadium on ax feels usable where ac would have folded.

Wi-Fi 6E

Same 802.11ax technology, one massive change: access to the 6 GHz band — up to 1,200 MHz of clean, greenfield spectrum with no legacy devices allowed. One-line difference: 6E isn't a new protocol, it's new land. After twenty years of fighting over scraps in 2.4 and 5, 6 GHz felt like being handed a whole new continent.

Wi-Fi 7 (802.11be)

The speed-and-latency generation: MLO, 320 MHz channels, 4096-QAM, preamble puncturing. One-line difference: Wi-Fi 7 lets a client use multiple bands at once and dodge interference mid-session. MLO is the feature that matters; the giant channels are the feature that demos well.

Wi-Fi 8 (802.11bn)

The reliability generation, targeting "Ultra High Reliability" instead of a bigger throughput number. One-line difference: Wi-Fi 8 makes APs cooperate — MAPC, Co-SR, Co-TDMA — instead of compete. After thirty years of every AP acting alone, the standard is finally admitting that dense Wi-Fi is a team sport.

Wi-Fi Sensing (802.11bf)

Using the Wi-Fi signals already bouncing around a space to detect motion, presence, even breathing — no cameras, no wearables, just disturbances in the RF. Home security and elder care are the early markets; occupancy analytics for venues is where I think it gets interesting. Your Wi-Fi network is about to become a sensor grid whether you planned for it or not.

WPA3

The current Wi-Fi security standard, replacing WPA2's crackable four-way handshake with SAE, which shrugs off offline dictionary attacks, plus mandatory PMF and Enhanced Open for portal-free encrypted guest access. Required on 6 GHz — no legacy security allowed in the new band. If you're still deploying WPA2-only networks in 2026, you're building a museum.