WIRELESS COMMUNICATIONS Flashcards
The most prevalent wireless technology
Cellphones
The WLAN uses a device called
Access point
Transfer rate for broadcast radio channel
upto 4Mbps
Transfer rate for microwave radio
45Mbps
Transfer rate for satellite radio channel
50Mbps
Transfer rate for cellular radio channel
9600bps to 14.4kbps
Transfer rate for infrared channel
1 to 4 Mbps
___________ Transmission is when the original signal such as a voice, or digital signal is put directly into the medium
Baseband transmission
This high frequency is added to the baseband signal so that it can radiate well in space
Carriers
It is the process of adding the carrier signal to the baseband signal and then modulated to be amplified and then sent to the antenna
Broadband transmission
when was the first LAN established?
1971
The experiment in which the first LAN was established
ALOHANET
The type of topology the ALOHANET used
Star topology network
Give the wireless technology for Wireless Ethernet LAN
Wi-Fi 802.11
Give the wireless technology for short-range wireless (commonly used in audio)
Bluetooth
Give the wireless technology for home/industrial monitoring control
ZigBee 802.15.4
Give the wireless technology for high speed and short-range for computer peripherals and video connections
Ultrawideband
Give the wireless technology for MAN broadband wireless
WiMAX 802.16
Give the wireless technology for wireless barcode used for tracking and ID
RFID
Give the wireless technology for ultrashort range for smart cards and ID
NFC
Give the wireless technology for mixed-used unlicensed short-range telemetry and control
ISM
Give the wireless technology for optical wireless for control and data
IR
Give the wireless technology for wireless telemetry and control and internet access
White space radio
It is the interconnection between nodes
Communication link
A type of network that covers a large geographical area
WAN
Type of network that covers a city, town, or village
MAN
The smallest type of network
LAN
A short-range wireless network
PAN (Personal Area Network)
The generic term which refers to the IEEE 802.11 communications standard for WLAN
Wireless Fidelity (Wi-Fi)
WiFi radios that work with the 802.11b and 802.11g standards transmit up to _______
2.4GHz
The ISM Band for 802.11a
56GHz
radios used for WiFi have the ability to _______ frequencies
Change frequencies
It is a method of transmitting signals by rapidly switching the carrier between different frequency channels
Frequency Hopping
The advantage of this method is that it is more immune to interference and can allow dozens of WiFi cards to talk simultaneously
Frequency Hopping
It is the group of radio bands that are intentionally reserved for these radio frequency energy intended for scientific, medical and industrial requirements rather than for communications
ISM (Industrial, Scientific, Medical)
In this frequency band, interference occurs a lot
ISM (Industrial, Scientific, Medical)
The earliest useful and most widely adopted version of 802.11 standard
802.11b
The access method used in 802.11b
Direct Sequence Spread Spectrum (DSSS)
The 802.11b has ___ channels and ___ non-overlapping channels
11, 3
ISM Band for 802.11b
2.4GHz
the total bandwidth for 802.11b
83.5MHz
The maximum data rate for 802.11b
11 Mbps
The back-off rates for 802.11b
1, 2, 5.5 Mbps
The maximum distance at the maximum data rate of 802.11b
100m
The channels in 802.11b are spaced ____ apart over the spectrum
5MHz
Each channel in 802.11b is ___ wide, which is why they overlap
22MHz
a modulation technique used to achieve faster rates such as 11Mbps and 5.5Mbps
CCK (Complementary Code Keying)
This type of modulation technique improves the performance of the signal under noise and multipath conditions due to their unique codes and properties that make them easier to identify and decode
CCK(Complementary Code Keying)
The equivalent isotropic radiated power for 802.11b is
1 W
when did the IEEE 802 Executive Committee establish the 802.11 working group to create a WLAN standard?
1990
UNII meaning
Unlicensed National Information Infrastructure band
when did 802.11a come out?
1991
What is the ISM band for 802.11a?
5GHz
The three authorized frequency segments of 802.11a
5.15 GHz to 5.25 GHz - 50mW power
5.25 GHz to 5.35 GHz - 250mW power
5.725 GHz to 5.825 GHz - 1W max power
maximum power for 5.15 GHz to 5.25 GHz 802.11a frequency segment?
50mW power
maximum power for 5.25 GHz to 5.35 GHz 802.11a frequency segment?
250mW power
maximum power for 5.725 GHz to 5.825 GHz 802.11a frequency segment?
1W max power
The access method for the 802.11a standard?
Orthogonal Frequency Division Multiplexing (OFDM)
Compared to 802.11b, this standard offers a wide range of data rates. The highest is 54 Mbps
802.11a
Channels for 802.11
23 (nonoverlapping)
Each channel in the 802.11a standard carries an OFDM signal made up of __ subcarriers, ____ for data, and other _____ for error corrections.
52 subcarriers
48 for data
4 for error corrections
Each subcarrier in the 802.11a standard is ____ wide
300khz
The maximum data rate for 802.11a standard
54 Mbps