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Criado por Scott Coleman
mais de 8 anos atrás
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Questão | Responda |
lesson 4 and 5 | . |
What are regulatory bodies? | Each country has its own set of regulations that determines what type of signal (what shape and power level) can be sent in each part of the global RF spectrum |
What is Canada's Regulatory Body? | CRTC, Canadian Wireless Telecommunications Association (CWTA) and The Canadian Wireless Telecommunications Association (CWTA |
How many Channels according to the FCC in 2.4ghz band? | allows channels 1 to 11 in 2.4GHz band, indoor and outdoor |
In 5 GHZ its dependent on the sub band. How many sub bands are under 5 Ghz? | 4 sub bands UNII-1, UNII-2, UNII-2 extended, UNII-3 |
all sub bands are approved for indoor but which is restricted from out door use? | UNII-1 |
How wide are WLAN channels? | 20 to 22 MHz–wide Note: If you want to use several channels in the same physical space, they must be nonoverlapping |
Which Channels are non overlapping? | Channels 1, 6, and 11 are nonoverlapping Note: some European countries use channels 1, 5, 9, and 13 for data |
What standards govern the 2.4 GHZ band | Used by the 802.11, 802.11b, 802.11g, and 802.11n |
How many channels in 5GhzÉ | 23 nonoverlapping channels |
How many channels in the 5 Ghz spectrum? | 23 nonoverlapping channels |
What Standards govern the 5Ghz band? | the 802.11a, 802.11n and 802.11ac standards |
Which band has less interference | 5ghz 2.4 has more because of higher use |
What is Modulation? | Modulation is the way in which the symbols are represented through the radio wave itself |
Differential Binary Phase Shift Keying (DBPSK) does what to the wave when it hits a 1? | When the next value to send is a 1, change direction (if the wave was going up, suddenly go down, and vice versa) The result is a 1 Mbps communication |
Differential Quadrature Phase Shift Keying (DQPSK) does what differently? | Sends symbols of grouped 1's and 0's instead of 1 OR 0 (00, 01, 10, 11) and changes in 90 degree increments allowing for 2 Mbps data transmission |
Complementary Code Keying (CCK) uses 6 bit symbols to achieve what speed? under what IEEE standard? | 11 Mbps, 802.11.b Standard. |
to avoid over lap we use orthogonal (at 90 degree angle of one another) or ? | Orthogonal Frequency Division Multiplexing (OFDM) |
OFDM is used in what IEEE standards? | Used in 802.11a, 802.11n, and 802.11ac |
BPSK and QSK adjusted where the wave started from what does QAM also adjust for faster transmission? | QAM changes the amplitude Four amplitudes times four directions create 16 possibilities |
To improve reliability and resistance QAM repeats the packets. (match not question) | 1/2 the symbols are repeated, and allows for 24 Mbps 36 Mbps by only repeating 1/4 |
That was 16-QAM next is 64-QAM (not a question) | 64-QAM allows 1 Mbps per carrier, or 48 Mbps 2/3 of the bits are new information bits and 1/3 of the bits are redundant 1/4 redundant bits, the speed can increase to 54 Mbps (1.125 Mbps per carrier |
What is dynamic rate shifting (DRS). | 802.11 networks, operating in the 2.4-GHz range, the devices can rate-shift from 11 Mbps to 5.5 Mbps, and further to 2 and 1 Mbps depending on the circumstances. IE; distance, interference, signal quality |
802.11b Characteristics? | ratified in September 1999 2.4-GHz band Direct Sequence Spread Spectrum 1, 2, 5.5, 11 Mbps 36 dBm |
802.11g Characteristics? | published in 2003 2.4-GHz ISM with OFDM 12 data rates of up to 54 Mbps. 1, 2, 5.5, 11 Mbps (DSSS / 802.11b) 6, 9, 12, 18, 24, 36, 48, 54 Mbps (OFDM) 20 dBm for DSSS, but only 15 dBm for OFDM |
802.11a Characteristics? | ratified September 1999. the 5-GHz spectrum Uses Orthogonal Frequency-Division Multiplexing (OFDM) Uses eight data rates of up to 54 Mbps 6, 9, 12, 18, 24, 36, 48, 54 Mbps |
802.11n Characteristics? | Ratified as standard on September 11, 2009 Operates at both 2.4 and 5 GHz MIMO Data rate up to 600Mbs |
What is MIMO? | Multiple-Input Multiple-Output Uses multiple radios and antennas |
What technologies support MIMO | Spatial Multiplexing (SM) Multi Ratio Combining (MRC) Transmit Beamforming (TxBF) |
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