Chapter 6 Flashcards
FHSS systems use how many 1MHz channels within the 2.4 GHz ISM Band?
79
If an HR-DSSS device is used, what is the maximum Data Rate?
11 Mbps
Used for 802.11 legacy and Bluetooth, this communication technology hops through 75 to 79 1MHz wide channels within the 2.4 GHz ISM band to increase resiliency.
FHSS
How many channels in the 2.4 GHz ISM band are allowed for use by the FCC in the U.S.?
11
802.11n uses which communication technology?
HT-OFDM
How many subcarriers are used in each OFDM channel including data and pilot channels?
52
Used for 802.11b, this communication technology uses Complementary Code Keying (CCK) to improve data rates and uses 8-bit “chips” to represent up to 8-bits of data.
HR-DSSS
HR-DSSS runs in which frequency band?
2.4 GHz ISM
Which technologies are used in the 2.4GHz ISM band? (Choose all that apply)
ERP-OFDM
FHSS
HR-DSSS
DSSS
What is the maximum number of access points (radios) that can be colocated in the same physical area without channel overlap in the 2.4GHz ISM band?
3
What is the average amount of aggregate throughput percentage at any data rate in a typical 802.11 system?
50%
How much bandwidth is available on a single 802.11g channel?
20 MHz
Used for 802.11a, this communication technology transmits on 52 subcarriers and uses error checking and correcting known as convolutional coding for resiliency.
OFDM
If data is corrupted by previous data from a reflected signal, this is known as what?
Inter-Symbol Interference
Which current technology uses FHSS?
Bluetooth
Select the three non-overlaping 2.4GHz channels available in the United States
1
6
11
Which modulation technique is used by OFDM systems communicating at 54 Mbps?
64-QAM
What is the estimated throughput of a system using ERP-OFDM and 64-QAM at max speed?
20 to 29 Mbps
How many channels are specified for use with HR-DSSS by the IEEE?
14
ERP-OFDM runs in which frequency Band?
2.4 GHz ISM
Used for 802.11 legacy, this communication technology adds redundant data to the transmission and uses 11-bit “chips” to represent 1-bit of data.
DSSS
What best describes hop time?
The period of time that the transmitter takes to hop to the next frequency
Which of the following systems has the best balance of throughput and resilience?
OFDM
What is the Data Rate of a system using ERP-OFDM and 64-QAM at max speed?
54 Mbps
