Which of the following standards is a proposed enhancement to the 802.11a and 802.11b wireless LAN (WLAN) specifications that offers quality of service (QoS) features, including the prioritization of data, voice, and video transmissions?
- 802.15
- 802.11n
- 802.11e
- 802.11h
Answer(s): C
Explanation:
The 802.11e standard is a proposed enhancement to the 802.11a and 802.11b wireless LAN (WLAN) specifications. It offers quality of service (QoS) features, including the prioritization of data, voice, and video transmissions. 802.11e enhances the 802.11 Media Access Control layer (MAC layer) with a coordinated time division multiple access (TDMA) construct, and adds error-correcting mechanisms for delay-sensitive applications such as voice and video. Answer option D is incorrect. 802.11h refers to the amendment added to the IEEE 802.11 standard for Spectrum and Transmit Power Management Extensions.
Answer option B is incorrect. 802.11n is an amendment to the IEEE 802.11-2007 wireless networking standard to improve network throughput over the two previous standards - 802.11a and 802.11g - with a significant increase in the maximum raw data rate from 54 Mbit/s to 600 Mbit/s with the use of four spatial streams at a channel width of 40 MHz. Answer option A is incorrect. IEEE 802.15 is a working group of the IEEE 802 and specializes in Wireless PAN (Personal Area Network) standards. It includes seven task groups, which are as follows:
1.Task group 1 (WPAN/Bluetooth)
2.Task group 2 (Coexistence)
3.Task group 3 (High Rate WPAN)
4.Task group 4 (Low Rate WPAN)
5.Task group 5 (Mesh Networking)
6.Task Group 6 (BAN)
7.Task group 7 (VLC)
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