Term
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Definition
| Communication technique that spreads a narrowband communication signal over a wide range of frequencies for transmission, and then de-spreads it into the original data bandwidth at the receiver. |
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Term
| What is Narrowband Transmission? |
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Definition
| Technology that uses only enough of the frequency spectrum to carry the data signal, and no more. |
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Definition
| The Background level of RF noise. |
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Definition
Power level of the Narrowband signal relative to the power-level of the Noise-floor.
Expressed in dB. |
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Definition
| Because Narrowband signal use such a small frequency range, they can be jammed or experience interference easily. True |
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Term
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Definition
| Intentional overpowering of an intended transmission by transmitting unwanted signals in the same frequency range. |
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Definition
| The FCC DOES NOT require licenses for all narrowband transmitters. False |
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Term
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Definition
| Spread Spectrum uses 'wide-frequency' range at 'low power-levels'. TRUE |
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Term
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Definition
| In multi-path environments the main cause interference is 'inter-symbol interference'. TRUE |
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Term
| Which 802.11X standard was the first to use OFDM? |
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Definition
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Term
| 802.11a operates in which GHz UNII band? |
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Definition
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Term
| True/False: OFDM is a spread-spectrum technology? |
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Definition
| False. Is actually FHSS but has functionality of DHSS. |
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Term
| FHSS (Frequency Hopping Spread Spectrum): |
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Definition
| A spread spectrum technique that uses frequency agility to spread the data over more than 83 MHz. |
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Term
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Definition
| IEEE usually specifies slightly more conservative frequency ranges than the FCC allows. TRUE |
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Term
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Definition
| Time that FHSS systems must transmit (dwell) on a specified frequency for a time then 'hop' to a different frequency to continue transmitting. |
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Term
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Definition
| Small amount of time between frequency changes of FHSS. |
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Term
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Definition
| During FHSS, the process of changing to the new frequency must be complete before transmission can resume. TRUE |
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Term
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Definition
| Hop time is treated as 'overhead' since no transmission occurs during that time period. TRUE |
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Term
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Definition
| The process of 'adding redundant information' the the data. |
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Term
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Definition
| PN code XOR'd to the data-stream bit (fixed length). |
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Term
| Phase Shift Keying (PSK): |
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Definition
| When wireless networks represent information by manipulating the 'phase' of the signal. |
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Term
| Differential Phase Shift Keying (DPSK): |
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Definition
| A specific type of PSK; encodes information by advancing the phase of the signal by some number of degrees. |
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Term
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Definition
| Since phase shift represents two chips instead of one, DQPSK has twice the data rate DBPSK at the same signaling rate. TRUE |
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Term
| What are the data rates represented by DPSK/DPBSK/DQPSK? |
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Definition
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Term
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Definition
| Complimentary Code Keying (CCK) uses an 8-chip PN code. TRUE |
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Term
| What are the data rates represented by CCK? |
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Definition
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Term
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Definition
| CCK allows for more data to be squeezed into the transmission channel while the chipping rate stays the same. TRUE |
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Term
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Definition
| CCK uses the same PN code for every bit sequence. FALSE |
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Term
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Definition
| Refers to characteristic of the RF signal that is manipulated in order to represent data. |
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Term
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Definition
| Refers to the way in which the changes in the signal are translated into 'ones' and 'zero's'. |
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Term
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Definition
| Orthogonal Frequency Division Multiplexing |
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Term
| What data rates are provided with OFDM? |
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Definition
| Up to 54 Mbps in 802.11a and 802.11g |
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Term
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Definition
| Does NOT offer the highest data rates and maximum resistance to interference and corruption of all the signal manipulation techniques in use today. FALSE |
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Term
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Definition
| Achieves high data rates by squeezing a large number of communication channels into a given frequency band. |
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Term
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Definition
| Mathematical technique used to increase OFDM's resistance to narrowband interference. |
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Term
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Definition
| Convolution Coding is a form a 'error' correction in which redundant information analogous to a parity-bit file system is added to the data. TRUE |
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Term
There are three 5GHz UNII bands in OFDM.
They are: |
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Definition
High (UNII-3)
Middle (UNII-2)
Low (UNII-1) |
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