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Wi-Fi Complete Series · Part 5 of 6 Mesh, Repeaters & Powerline: Extending Wi-Fi CoverageWhich technology fits which use case? Coverage planning, roaming and professional AP infrastructure Repeater · Mesh Systems · Powerline · AP Placement · Site Survey · Seamless Roaming (802.11r/k/v) |
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Contents
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Repeater, Mesh & Powerline: Direct Comparison
Three common methods to extend WLAN coverage — each with its strengths and ideal use cases:
| Criterion | WLAN Repeater | Mesh System | Powerline + WLAN |
| Setup Effort | Very low | Low to medium | Low |
| Network Quality | Medium (half-duplex loss) | Very good | Good (depends on wiring) |
| Roaming | Limited | Seamless (one SSID) | Depends on model |
| Same circuit needed? | No | No | Yes! |
| B2B Suitability | Limited | High (consumer) / Very high (enterprise) | Medium (workaround) |
| Cost | <50 EUR | 150–2,000 EUR/node | 50–200 EUR |
WLAN Repeaters in Detail
A WLAN repeater (also: range extender) receives the existing Wi-Fi signal and retransmits it. It is the simplest and cheapest method to extend coverage — but with inherent limitations:
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Technical Limitations: ⚠ Half-duplex: receive + transmit on same channel = ~50% throughput loss ⚠ No seamless roaming (no 802.11r support) ⚠ Client decides when to switch — "sticky client" problem ⚠ Placement is critical: too far = weak input signal; too close = minimal gain |
When Repeaters Make Sense: ✓ Dead zone in one corner ✓ Temporary fix pending cabling ✓ Single room with 1–2 stationary devices ✓ Very tight budget ✗ Not for mobile roaming (VoIP, scanners) |
Optimal placement: The repeater should be placed where the original signal is at least 50% strength (–60 to –65 dBm RSSI). Too weak an input signal = barely usable output signal.
Dual-band repeaters with dedicated backhaul: Modern repeaters use the 5 GHz band as a backhaul (connection to the router) and the 2.4 GHz band for clients. This partially circumvents the half-duplex problem — a first step towards mesh.
Mesh Systems: One Network, Many Nodes
Mesh systems build a completely new, unified network from multiple equal-ranking nodes. All nodes share a common SSID — the client always connects to the strongest node without noticing.
| Consumer Mesh (e.g. TP-Link Deco, eero, FRITZ!Mesh) Easy app-based setup. Good roaming for home users. Limited for enterprise: no 802.1X, no VLAN management. |
Enterprise Mesh (e.g. Cisco Meraki, Aruba Instant On, Ubiquiti UniFi) Central cloud management. 802.1X, VLAN, QoS, monitoring. Professional fast roaming (802.11r/k/v). Wired backhaul option. |
Backhaul Options: Wireless Backhaul: No cable needed, but bandwidth overhead. Wired Backhaul: Cable between nodes = no backhaul overhead, maximum performance. Always prefer where possible. |
Powerline Adapters
Powerline adapters transmit network data over the existing electrical wiring. One adapter connects to the router via LAN cable; the second plugs into another outlet (ideally on the same circuit) and provides WLAN or LAN there.
| Advantages: ✓ No network cabling needed ✓ Good for thick concrete walls ✓ Up to 2,400 Mbit/s (G.hn/HomePlug AV2) ✓ Stable connection without signal fluctuations |
Limitations: ⚠ Works only on the same electrical circuit ⚠ RCD switches and power strips block signal ⚠ Variable performance depending on wiring age ⚠ Old installations (pre-1990) problematic |
Coverage Planning & Site Survey
Every professional WLAN installation starts with a site survey — a systematic radio frequency measurement of the building.
| Passive Site Survey Receive-only. Maps all existing WLAN signals, overlaps and interference. Tools: Ekahau Sidekick, AirCheck G3. |
Active Site Survey Real test APs simulate the planned infrastructure. Throughput, latency and packet loss measured. Result: heatmap. |
Predictive Survey Software-based: floor plan + wall material + AP type = automated coverage prediction. Tools: Ekahau Pro, Hamina. |
| Material | Attenuation 2.4 GHz | Attenuation 5 GHz | Note |
| Drywall | 3–5 dB | 5–8 dB | No issues |
| Solid brick | 6–15 dB | 10–20 dB | Measure specifically |
| Reinforced concrete | 15–30 dB | 20–40 dB | Critical; plan one AP per room |
| Normal glass | 2–3 dB | 3–5 dB | Little attenuation |
| Safety glass / metal foil | 15–50 dB | 20–60 dB | Can block WLAN completely |
Roaming & Seamless Handover
Roaming refers to a client switching from one access point to another while maintaining an active connection. Rarely critical in home networks — but essential in professional environments (VoIP phones, barcode scanners, mobile devices).
| 802.11r — Fast BSS Transition Reduces roaming time to <50 ms through pre-negotiated keys. Essential for real-time applications (VoIP, tracking). |
802.11k — Radio Resource Management AP shares neighbour AP information with the client. Client can proactively select the best AP before signal quality degrades. |
802.11v — BSS Transition Management AP can recommend (or force) the client to switch APs. Prevents "sticky client" behaviour despite better alternatives being available. |
Practical tip: Professional APs (Cisco, Aruba, Ubiquiti, Ruckus) support all three standards (802.11r/k/v) and configure roaming automatically. For industrial WLAN with <50 ms handover, 802.11r is essential.
FAQ
| Is mesh better than a repeater? |
| Almost always yes, especially for mobile devices. Mesh provides seamless roaming under one SSID, no throughput halving with wired backhaul, and central management. A repeater is cheaper and sufficient for stationary devices with low requirements. |
| How many access points do I need for 1,000 m²? |
| It heavily depends on building structure. Rule of thumb for normal offices (lightweight walls): 1 AP per 100–150 m² at normal user density. High density or reinforced concrete: 1 AP per 50–80 m². Only a professional site survey provides reliable values. |
| My device stays stuck on a weak AP — what can I do? |
| This "sticky client" behaviour is decided by the client itself. Solutions: APs with 802.11v support (AP can recommend roaming), configuring a minimum RSSI threshold (AP refuses weak clients), or forcing deauthentication. In consumer mesh systems this is often only resolvable by reconnecting. |
| Where should I place the access point? |
| Mount APs as high as possible: ceiling mounting provides optimal 360° radiation. Place centrally in the area to be served, away from metal furniture or concrete pillars. Direct line of sight to clients is ideal. Router/switch cabinets are often poor AP locations (too shielded). |
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Consulting & Supply Access Points, Mesh Systems & Powerline for B2B From Ubiquiti UniFi to Aruba Instant On and Cisco Meraki — we provide the right solution for your building size and user count. ► Phone: +49 (0)7666 / 88499-0 ► sales@industry-electronics.com |
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