Guys, does anyone know the answer?
get we know in wi-fi, ism works in the frequency range of 2.4ghz, while unii works in the frequency range of 5 ghz. expand ism and u-nii from screen.
Wi-Fi operates within defined bands of frequencies as dictated by the Federal Communications Commission, specifically Part 15 of FCC rules. Wi-Fi operates | Control Engineering
Wi-Fi Spectrum: ISM, U-NII, FCC Rules
Wi-Fi Spectrum: ISM, U-NII, FCC Rules Industrial wireless tutorials, Wi-Fi explanation: Wi-Fi is part of the 12 industrial, scientific, and medical (ISM) bands. Newer Wi-Fi standards allow for the bonding of multiple channels to allow up to 160 MHz wide channel combinations for faster data rates, multiple transceivers, and a theoretical throughput of up to 7 GBPS when the latest ratified Wi-Fi amendment, IEEE 802.11ac, is fully implemented.
BY DANIEL E. CAPANO JULY 16, 2014
Wi-Fi operates within defined bands of frequencies as dictated by the Federal Communications Commission, specifically Part 15 of FCC rules. Wi-Fi operates in unlicensed frequency spectra, which means that anyone, within specified transmission power restrictions, can operate a transmitter within these bands.
There are 12 industrial, scientific, and medical (ISM) bands. Of these, two are in use: the 26 MHz centered around 915 MHz, and the 100 MHz centered around 2.450 GHz. Currently, only the latter band is used for Wi-Fi. The former is used for devices such as home automation (Zwave) and baby monitors. The 2.4 GHz band has a total of 14 channels, numbered 1-14. Channels 1-11 are allowed for use in the United States; 1-13 are used in Europe and Israel; 1-14 are used in Japan. Each channel is 22 MHz wide, with center frequencies of each channel separated by 5 MHz. As shown in Figure 1, only three channels do not overlap in the 11-channel model; therefore, only these channels can be used in a multi-channel architecture, or adjacent channel interference will render the network unusable.
As of this writing, there are 4 Unlicensed National Information Infrastructure bands (U-NII). There are a total of 23 U-NII channels available for use.4 bands within 5 GHz
The four bands in the 5GHz spectrum are:
U-NII-1 (lower) comprises four 20 MHz channels, 36-48 in the 100 MHz 5.150-5.250 GHz band.
U-NII-2A (lower middle) comprises four 20 MHz channels, 52-64 in the 100 MHz 5.250-5.350 GHz band.
U-NII-2C (upper middle) comprises 11 20 MHz channels, 100-140 in the 250 MHz 5.470-5.725 GHz band.
U-NII-3 (upper) comprises four 20 MHz channels, 149-161 in the 100 MHz 5.725-5.825 GHz band.
All four bands operate under power restrictions, with U-NII-1 being relegated to indoor use only. A recent rule change effectively opened up this band for general use, removing the indoor-only stricture, and allowing transmit power to rise to 1 W from 50 mW. For comparison, U-NII-2A and 2C can operate up to 250 mW, and U-NII-3 can operate up to 1 W. Another change will be to add ISM channel 165, at the center frequency of 5.825 GHz, to the U-NII-3 band, bringing another 25 MHz into play.More Wi-Fi bands proposed
Proposed new bands are under consideration by the FCC to add even more bandwidth for Wi-Fi use. U-NII-2B will add 120 MHz bandwidth in the 5.350-5.470 band. U-NII-4 will add another 75 MHz in the 5.850-5.925 GHz band.
The 20 MHz wide channels are actually very narrow in terms of data throughput. Newer Wi-Fi standards allow for the bonding of multiple channels to allow up to 160 MHz wide channel combinations. This will have the effect, along with faster data rates and multiple transceivers, to allow a theoretical throughput of up to 7 GBPS when the latest ratified Wi-Fi amendment, IEEE 802.11ac, is fully implemented.
– Daniel E. Capano, owner and president, Diversified Technical Services Inc. of Stamford, Conn., is a certified wireless network administrator (CWNA). Edited by Mark T. Hoske, content manager, CFE Media, , [email protected]ONLINE extras
www.controleng.com/blogs has other wireless tutorials from Capano on the following topics:
– What is wireless?
– Radio frequency basics
– Comparative modulation: Spread spectrum modulation terms and definitions for wireless networking
www.controleng.com/webcasts has wireless webcasts, some for PDH credit.
has a wireless page.
Do you have experience and expertise with the topics mentioned in this content? You should consider contributing to our CFE Media editorial team and getting the recognition you and your company deserve. Click here to start this process.
Unlicensed National Information Infrastructure
Unlicensed National Information Infrastructure
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The Unlicensed National Information Infrastructure (U-NII) radio band, as defined by the United States Federal Communications Commission, is part of the radio frequency spectrum used by WLAN devices and by many wireless ISPs.
As of March 2021, U-NII consists of eight ranges. U-NII 1 through 4 are for 5 GHz WLAN (802.11a and newer), and 5 through 8 are for 6 GHz WLAN (802.11ax) use. U-NII 2 is further divided into three subsections.
U-NII bands and FCC regs
Name Aliases Freq. Range (GHz) Bandwidth (MHz) Max Power (mW) Max EIRP (mW)
U-NII-1 U-NII Low / U-NII Indoor 5.150–5.250 100 50 200
U-NII-2A U-NII Mid 5.250–5.350 100 250 1,000
U-NII-2B 5.350–5.470 120 — —
U-NII-2C U-NII Worldwide / U-NII-2-Extended / U-NII-2e 5.470–5.725 255 250 1,000
U-NII-3 U-NII Upper 5.725-5.850 125 1,000 20,000
U-NII-4 DSRC/ITS 5.850–5.925 75 — —
U-NII-5 5.925–6.425 500 — —
U-NII-6 6.425–6.525 100 — —
U-NII-7 6.525–6.875 350 — —
U-NII-8 6.875–7.125 250 — —
Wireless ISPs generally use 5.725–5.825 GHz.
In the USA licensed amateur radio operators are authorized 5.650–5.925 GHz by Part 97.303 of the FCC rules.
U-NII power limits are defined by the United States CFR Title 47 (Telecommunication), Part 15 - Radio Frequency Devices, Subpart E - Unlicensed National Information Infrastructure Devices, Paragraph 15.407 - General technical requirements.
Many other countries use similar bands for Wireless communication due to a shared IEEE standard. However, regulatory use in individual countries may differ.
The defunct European HiperLAN standard operates in same frequency band as the U-NII.
1 5 GHz (802.11a/h/j/n)
2 See also 3 References 4 External links
5 GHz (802.11a/h/j/n)
This section may require cleanup to meet Wikipedia's quality standards. The specific problem is: Better just link to List of WLAN channels instead of having this hard-to-maintain table. Please help improve this section if you can.
It operates over four ranges:
U-NII Low (U-NII-1): 5.150–5.250 GHz. Originally limited to indoor use only. Regulations required use of an integrated antenna, with power limited to 50 mW. Rules changed in 2014 to permit outdoor operation, maximum fixed power 1 watt, maximum fixed EIRP 4 watts (+36 dBm) point-to-multipoint, 200 watts (+53 dBm) point-to-point.  However, strict out-of-band emission rules limit practical point-to-point power to lower levels.
U-NII Mid (U-NII-2A): 5.250–5.350 GHz. Both outdoor and indoor use, subject to Dynamic Frequency Selection (DFS, or radar avoidance). Regulations allow for a user-installable antenna. Power limited to 250 mW.
U-NII-2B: 5.350–5.470 GHz. Currently 120 MHz of spectrum not allocated by the FCC for unlicensed use.
U-NII Worldwide (U-NII-2C / U-NII-2e): 5.470–5.725 GHz. Both outdoor and indoor use, subject to Dynamic Frequency Selection (DFS, or radar avoidance). Power limited to 250 mW. This spectrum was added by the FCC in 2003 to "align the frequency bands used by U-NII devices in the United States with bands in other parts of the world". The FCC currently has an interim limitation on operations on channels which overlap the 5600–5650 MHz band.
U-NII Upper (U-NII-3): 5.725–5.850 GHz. Sometimes referred to as due to overlap with the ISM band. Regulations allow for a user-installable antenna. Power limited to 1W
DSRC/ITS (U-NII-4): 5.850–5.925 GHz. At present U-NII-4 spectrum is being considered by the FCC for unlicensed use. U-NII-4 is presently only usable for Dedicated Short Range Communications Service (DSRC) and licensed amateur radio operators.
In 2007, the FCC began requiring that devices operating in channels 52, 56, 60 and 64 must have Dynamic Frequency Selection (DFS) capabilities. This is to avoid communicating in the same frequency range as some radar. In 2014, the FCC issued new rules for all devices due to interference with government weather radar systems. Fines and equipment seizure were listed as punishment for non-compliance.
Band Channel Frequency
(MHz) United States Europe Japan Singapore China Israel Korea Turkey India United Kingdom
40/20 MHz 40/20 MHz 40/20 MHz 10 MHz 20 MHz 20 MHz 20 MHz 20 MHz 20 MHz 40/20 MHz 5/10 MHz 80/40/20 MHz
183 4915 No No No Yes No No No No No No Yes No
184 4920 No No Yes Yes No No No No No Yes Yes No
185 4925 No No No Yes No No No No No No Yes No
187 4935 No No No Yes No No No No No No Yes No
188 4940 No No Yes Yes No No No No No Yes Yes No
189 4945 No No No Yes No No No No No No Yes No
192 4960 No No Yes No No No No No No Yes Yes No
196 4980 No No Yes No No No No No No Yes Yes No
7 5035 No No No Yes No No No No No No No No
8 5040 No No No Yes No No No No No No No No
9 5045 No No No Yes No No No No No No No No
11 5055 No No No Yes No No No No No No No No
12 5060 No No No No No No No No No No No No
16 5080 No No No No No No No No No No No No
U-NII-1 34 5170 No No No No No No Yes Yes Yes Yes Yes No
36 5180 Yes Yes Yes No Yes No Yes Yes Yes Yes Yes Yes
38 5190 No No No No No No Yes Yes Yes Yes Yes No
Chapter 6: Wireless Networks and Spread Spectrum Technologies Flashcards
Study with Quizlet and memorize flashcards containing terms like 902-928 MHz (26 MHz wide) represents the ________ band, 2.4-2.5 GHz (100 MHz wide) represents the __________ band, 5.725-5.875 GHz (150 MHz wide) represents the _______ band and more.
Chapter 6: Wireless Networks and Spread Spectrum Technologies
3.0 (1 review) Term 1 / 92
902-928 MHz (26 MHz wide) represents the ________ band
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Definition 1 / 92 Industrial
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Created by Sean_Klinger
Terms in this set (92)
902-928 MHz (26 MHz wide) represents the ________ band
2.4-2.5 GHz (100 MHz wide) represents the __________ band
5.725-5.875 GHz (150 MHz wide) represents the _______ band
Bands are defined by the ___-_
ITU-T (ITU telecommunication standardization sector)
The ___ MHz ISM Band is used by many consumer products, including baby monitors and cordless home telephones.
900 (through 928 MHz)
The 2.4 GHz ISM band is ___ MHz wide, and is the most ______ Wi-Fi band
Use for WLANs is defined by IEEE ___.__-____ standard and 802.11_ amendment
The 2.4 GHz ISM band is used by 802.11, 802.11_, 802.11_ and 802.11_ wireless devices.
b, g, n
The 5.8 GHz ISM band is ___ MHz wide
The _._ ___ ISM Band is commonly confused with the UNII-3 band.
Some countries allow the use of OFDM on channel ___, but only sparsely
UNII bands were designated for use by IEEE 802.11_
Each UNII band is ___ MHz wide with _ channels
IEEE 802.11h designated the use of ____-__
UNII-2E is ___ MHz wide with __ channels
255, 11 (UNII-2 Extended)
T/F UNII-1 is typically used outdoors.
F (typically used indoors)
UNII-1 Has a defined max power of __ mW
UNII-1 is also known as ____ UNII
UNII-2 is also known as _____ UNII
T/F UNII-2 is defined for indoor or outdoor use.
UNII-2 Has a defined max power of ___ mW
UNII-2 Extended is ___ MHz wide
UNII-3 is also known as _____ UNII
T/F UNII-3 is typically used for outdoor point-to-point connections.
UNII-3 has a defined max power of ___ mW
The 3.6 GHz Band was specified by the 802.11_ amendment
Use of the 3.6 to 3.7 band is limited near _______ stations
The _._ GHz ISM band is the dominant license-free frequency band.
The use of 5 GHz began to grow in ____
5 GHz continues to grow due to ___________ in the 2.4 GHz band, _____ channels, and benefits in 802.11n channel _______.
overcrowding, more, bonding
The proposed 60 GHz band has potential speeds of _ Gbps
T/F Ultrahigh frequencies can penetrate walls easily.
F (Very difficult to penetrate at high frequency)
In September 2012, the Wi-Fi Alliance designated the _____ certification to test interoperability of products in the 60 GHz band.
_____-__ makes use of Wi-Fi in the unused television RF spectrum, providing greater range at lower frequencies.
_________ uses very little bandwidth, but intentional jamming or interference can disrupt the signal.
Narrowband is typically transmitted using _____ power
______ spectrum uses more bandwidth than necessary to carry data. It is less susceptible to jamming or interference.
spread spectrum is typically transmitted using _____ power
T/F spread spectrum technologies require a license
F (typically do not)
Prior to 802.11_, multipath was unwanted.
Frequency Hopping Spread Spectrum is now used by ________.
The ____ process involves transmitting data on a narrow frequency, then hopping to a new frequency and transmitting more data.
The ____ time in FHSS is the period of time a transmitter stays on a channel to transmit.
The ___ time is the time it takes for a FHSS transmitter to change from one frequency to another.
FHSS uses ________ frequency shift keying for modulation.
Direct Sequence Spread Spectrum (DSSS) was defined in ___.__ clause __. High Rate DSSS (HR-DSSS) was defined in 802.11_.
802.11, 15, b
DSSS provided _ and _ Mbps, while HR-DSSS added _._ and __ Mbps
1, 2, 5.5, 11
DSSS added additional, redundant information to the data, known as ___________ gain.
Processing gain makes signals more resistant to data __________.
A bit of data in DSSS is converted into a series of _____.
802.11 used 11-chip ______ code
HR-DSSS uses a faster, more complex code process, known as ___.
CCK (Complimentary Code Keying)
CCK Uses _-Chip code
Barker coding encodes 1 bit with __ chips
DSSS modulates its signal using two methods: Differential ______ phase shift keying (DBPSK) and Differential __________ phase shift keying (DQPSK)
Packet Binary Convolutional Code is one of the optional __________ techniques in 802.11b.
T/F PBCC is often deployed in enterprise environments
F (Rarely deployed in enterprise environments)
Orthogonal Frequency Division Multiplexing transmits across __ subcarriers, each ___._ KHz wide.