802.11n Channels ====================== .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What are channels in 802.11n?** Channels in 802.11n refer to specific frequency ranges in the 2.4 GHz and 5 GHz bands, supporting both 20 MHz and optional 40 MHz widths. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How many channels are available in 802.11n?** In 2.4 GHz, up to 14 channels exist globally; in 5 GHz, dozens of channels are available depending on region and DFS rules. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is a frequency band in wireless communication?** A frequency band is a defined portion of the radio spectrum, such as 2.4 GHz or 5 GHz, used for wireless transmission. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Which frequency band does 802.11n operate in?** 802.11n operates in both the 2.4 GHz and 5 GHz frequency bands, offering improved performance and flexibility. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What are UNII bands in 802.11n?** UNII (Unlicensed National Information Infrastructure) bands are 5 GHz spectrum segments used for unlicensed wireless communication. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What are UNII-1, UNII-2, and UNII-3 bands?** These are subdivisions of the 5 GHz spectrum, each with specific rules for power, DFS, and allowed usage. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is channel width in 802.11n?** Channel width defines the size of the frequency band used for data. 802.11n supports 20 MHz and 40 MHz channels. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Why does 802.11n use 20 MHz and 40 MHz channels?** 20 MHz channels are more compatible and less prone to interference; 40 MHz offers higher speeds but may overlap with adjacent channels. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Are 802.11n channels overlapping?** In 2.4 GHz, yes — especially with 40 MHz mode. In 5 GHz, channels are typically non-overlapping due to greater spacing. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What determines the number of usable channels?** Regulatory domain, band (2.4 or 5 GHz), DFS/TPC requirements, and interference determine usable channels. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is Dynamic Frequency Selection (DFS)?** DFS enables 802.11n devices to detect radar and automatically switch channels to avoid interference in 5 GHz UNII-2 bands. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is Transmit Power Control (TPC)?** TPC dynamically adjusts transmission power to reduce interference and stay within regulatory limits. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Can 802.11n use 40 MHz or 80 MHz channels?** 802.11n supports up to 40 MHz channels. 80 MHz and wider are supported in later standards like 802.11ac and 802.11ax. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Why is channel planning important in 802.11n?** Effective planning minimizes co-channel interference and ensures optimal performance, especially with 40 MHz usage. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Are all 5 GHz channels available globally?** No, availability depends on country-specific regulations and enforcement of DFS/TPC requirements. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Can devices auto-select 802.11n channels?** Yes, modern devices often auto-select based on interference, regulatory limits, and signal strength. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How do clients know which channel to use?** Clients scan available channels and select an access point based on beacon signals and quality metrics. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is the channel center frequency?** The center frequency is the midpoint of a channel’s frequency range (e.g., Channel 36 = 5.180 GHz). .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How are 802.11n channels numbered?** In 2.4 GHz, channels are numbered 1–14; in 5 GHz, common numbers include 36, 40, 44, 48, 149, 153, etc. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What are the typical channel numbers for 802.11n?** In 2.4 GHz: 1, 6, 11; in 5 GHz: 36–64, 100–144, and 149–165, depending on region. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How far apart are 802.11n channels spaced?** In 2.4 GHz, channels are 5 MHz apart; in 5 GHz, 20 MHz apart. 40 MHz bonds two adjacent channels. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is co-channel interference?** It occurs when multiple devices use the same channel, causing packet collisions and reduced throughput. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How can co-channel interference be avoided in 802.11n?** By using non-overlapping channels and proper AP spacing, especially in 2.4 GHz. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Does weather affect 5 GHz channel performance?** Indoors, minimal effect. Outdoors, 5 GHz is more affected by rain and obstructions than 2.4 GHz. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Why is 5 GHz considered less congested than 2.4 GHz?** More available channels and fewer legacy devices reduce interference in 5 GHz. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is the typical range of 802.11n channels?** Indoors: ~30–70 meters depending on frequency, antenna setup, and obstacles. 2.4 GHz has longer range than 5 GHz. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Can 802.11n channels be used outdoors?** Yes, but only with adherence to DFS, TPC, and local regulations, especially in the 5 GHz band. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What happens if two APs use the same channel?** They compete for airtime, causing contention and reducing efficiency and performance. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What tools help with 802.11n channel planning?** Tools like Wi-Fi analyzers, heatmapping software, and spectrum scanners help optimize channel usage and placement. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow Topics in this section, * :ref:`List of channels ` * :ref:`List of channel widths ` * :ref:`List of Bands ` * :ref:`Reference links ` .. _channels_n_step4: .. tab-set:: .. tab-item:: 2.4 GHz Channels for 802.11n ===================== ======================= ====================== ============== Channel Number (MHz) Center Frequency (MHz) Frequency Range DFS Required ===================== ======================= ====================== ============== 1 2412 2401 – 2423 No 2 2417 2406 – 2428 No 3 2422 2411 – 2433 No 4 2427 2416 – 2438 No 5 2432 2421 – 2443 No 6 2437 2426 – 2448 No 7 2442 2431 – 2453 No 8 2447 2436 – 2458 No 9 2452 2441 – 2463 No 10 2457 2446 – 2468 No 11 2462 2451 – 2473 No 12 2467 2456 – 2478 No (region dependent) 13 2472 2461 – 2483 No (region dependent) 14 2484 2473 – 2495 No (Japan only) ===================== ======================= ====================== ============== .. tab-item:: 5 GHz Channels for 802.11n ===================== ======================= ====================== ============== Channel Number (MHz) Center Frequency (MHz) Frequency Range DFS Required ===================== ======================= ====================== ============== 36 5180 5170 – 5190 No 40 5200 5190 – 5210 No 44 5220 5210 – 5230 No 48 5240 5230 – 5250 No 52 5260 5250 – 5270 Yes 56 5280 5270 – 5290 Yes 60 5300 5290 – 5310 Yes 64 5320 5310 – 5330 Yes 100 5500 5490 – 5510 Yes 104 5520 5510 – 5530 Yes 108 5540 5530 – 5550 Yes 112 5560 5550 – 5570 Yes 116 5580 5570 – 5590 Yes 120 5600 5590 – 5610 Yes 124 5620 5610 – 5630 Yes 128 5640 5630 – 5650 Yes 132 5660 5650 – 5670 Yes 136 5680 5670 – 5690 Yes 140 5700 5690 – 5710 Yes 144 5720 5710 – 5730 Yes 149 5745 5735 – 5755 No 153 5765 5755 – 5775 No 157 5785 5775 – 5795 No 161 5805 5795 – 5815 No 165 5825 5815 – 5835 No ===================== ======================= ====================== ============== .. _channels_n_step5: .. tab-set:: .. tab-item:: List of channel widths * channel widths .. _channels_n_step6: .. tab-set:: .. tab-item:: List of Bands ======================= ====================== ====================== ============================================================ Band Name Frequency Range (GHz) Frequency Range (MHz) Channels ======================= ====================== ====================== ============================================================ 2.4 GHz Band 2.400 – 2.485 2400 – 2485 1 – 14 (region dependent) UNII-1 5.150 – 5.250 5150 – 5250 36, 40, 44, 48 UNII-2 (DFS) 5.250 – 5.350 5250 – 5350 52, 56, 60, 64 UNII-2 Extended (DFS) 5.470 – 5.725 5470 – 5725 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, 144 UNII-3 5.725 – 5.825 5725 – 5825 149, 153, 157, 161, 165 ======================= ====================== ====================== ============================================================ .. _channels_n_step17: .. tab-set:: .. tab-item:: Reference links * Reference links