Wireless FundamentalsChapter 6

Introducing WirelessRegulation Bodies, Standards,

and Certifications

Objectives

• Describe the IEEE

• Describe the Wi-Fi Alliance

• Describe country code regulatory bodies such as the FCC and ETSI

• Describe the 802.11 family of protocols

• Describe the 802.11 original protocol

• Describe the 802.11b protocol

• Describe the 802.11g protocol

• Describe how 802.11b and 802.11g interact

• Describe the 802.11a protocol

• Describe the 802.11n protocol

• Describe the main components of the 802.11n protocol

IEEE Wireless Standards

The IEEEThe IEEE develops communication standards in electrical and computer sciences, engineering, and related disciplines.There are more than 1300 protocols.The 802.11 committee analyzes the applications and environments in which wireless networks are used and develops standards for them. The 802.11 family has more than 26 sub protocols.

The Wi-Fi Alliance

The Wi-Fi AllianceWi-Fi Alliance certifies interoperability between products WLAN products.The Wi-Fi Alliance was created to solve the compatibility issueProducts include 802.11a, 802.11b, 802.11g, 802.11n draft v2.0, dual-band products, and security testing.The organization provides assurance to customers of migration and integration options.Cisco is a founding member of Wi-Fi Alliance.Certified products can be found at http://www.wi-fi.com.

Regulatory Bodies

Each country or region defines its rules about the use of the RF space, including the following rules:Which frequencies are allowed (spectrums and channels)Which transmit powers are possible (transmitters and antennae gain and EIRP)How a wave can be sent in each frequency (modulation and encoding techniques)

Wireless Spectrum

The 2.4-GHz ISM band ranges from 2.4 to 2.4835 GHz (2.4970 GHz in Japan). In this range 11 channels are allowed in the United State, 13 in Europe, and 14 in Japan.

The 5-GHz ISM band ranges from 5.725 to 5.875 GHz. The 5-GHz ISM band overlaps with the Unlicensed National Information Infrastructure (UNII) bands:

– UNII-1 ranges from 5.15 to 5.25 GHz (4 channels).

– UNII-2 ranges from 5.25 to 5.35 GHz (4 channels).

– UNII-2 extended ranges from 5.470 to 5.725 GHz (up to 11 channels).

– UNII-3 ranges from 5.725 GHz to 5.825 GHz (4 channels).

Wireless Spectrum

The IEEE 802.11 Family of Protocols

Some IEEE 802.11 Standard Activities802.11a — 5GHz, 54 Mb/s; ratified in 1999802.11b — 2.4 GHz, 11 Mb/s; ratified in 1999802.11d — World Mode; ratified in 2001802.11e — QoS; ratified in 2005802.11g — 2.4GHz, 54 Mb/s; ratified in 2003802.11h — DFS and TPC mechanisms; ratified in 2004802.11i — Authentication and security; ratified in 2004802.11k — Radio resource measurement enhancements (underdevelopment)802.11n — Higher throughput improvements using MIMO antennas(under development)802.11t — WPP; test methods and metrics recommendation (underdevelopment)802.11w — Protected management frames (under development)

The 802.11 Standards for Channels and Speeds

The 802.11 Original Protocol

802.11 became a standard in July 1997, the first standard for wireless. Two RF technologies were defined: FHSS and DSSS. The standard allows 1 Mb/s and 2 Mb/s. It defined specifications for Layer 1 and Layer 2, and basic security 802.11 is defined in the 2.4-GHz ISM band. Three nonoverlapping channels is the most common deployment.

The 802.11b Protocol

11 Mb/s, 2.4 GHz, DSSS Ratified as standard in September 1999 11 U.S. channels 13 ETSI channels 14 Japanese channels Power levels: – 36 dBm Effective Isotropic Radiated Power (EIRP); FCC – 20 dBm EIRP; ETSI Approved for use nearly worldwide Not recommended for new deployments

802.11b Speed Coverage

Two different encodings:

- Barker 11

- CCK Two different modulations:

- DBPSK

- DQPSK Four different speeds:

- 1 Mb/s (Barker + DBPSK)

- 2 Mb/s (Barker + DQPSK)

- 5.5 Mb/s (CCK-16 + DQPSK)

- 11 Mb/s (CCK-128 + DQPSK)

The 802.11g Protocol

Standard for higher-rate extension in the 2.4-GHz ISM spectrum Speed up to 54 Mb/s OFDM added to DSSS Backward-compatible with 802.11b

802.11b/g Cell Speeds

802.11g speeds:

– 54 Mb/s, 48 Mb/s

– 36 Mb/s, 24 Mb/s

– 18 Mb/s, 12 Mb/s

– 9 Mb/s, 6 Mb/s

– Include 802.11b data rates Client looks for the best speed

802.11b/g Encoding and Modulations

802.11b and 802.11g Coexistence

802.11b presence triggers protection mode:

- RTS/CTS

- “CTS to self” protection “Non-ERP present” wave spreads

throughout the network. Throughput can drop from 22 Mb/s to 8 Mb/s.

The 802.11 a Protocol

Ratified as standard in September 1999 54 Mb/s 5 GHz (OFDM) 23 U.S. channels - Dynamic Frequency Control (DFS)* - Transmitter Power Control (TPC)* 19 ETSI channels (many countries)

- DFS

- TPC *Required by July 20th, 2007

802.11a Speeds

Same speeds as 802.11g No 802.11b interoperability Higher frequency, which implies lower range but also less scattering

Comparing the Technologies802.11a Data Rates

802.11n: State of the Protocol

IEEE is developing 802.11n standard features and attributes. Wi-Fi Alliance is using 802.11n Draft 2.0 in an interim baseline. Goal is for software upgrades to meet standard compliance and minimize hardware

upgrades.

Summary

• The IEEE defines the 802.11 family of protocols.

• The Wi-Fi Alliance ensures the interoperability of wireless devices.

• The local or regional regulatory bodies define what is allowed in which spectrum.

• The 802.11 family has more than 26 protocols.

• The original 802.11 protocol defined 1- and 2-Mb/s speeds with FHSS and DSSS.

• 802.11b increased the speed to 11 Mb/s.

• 802.11g increased the speed to 54 Mb/s, but still in the ISM band.

• 802.11b devices degrade the performances of 802.11g cells.

• 802.11a uses the same modulation and speed as 802.11g, but inthe 5-GHz band.

• 802.11n tries to increase speed and throughput in the ISM and

• UNII bands.