802.11N Rf Modulation Standard - ASCOM VoWiFi System System Description

System Description
Ascom VoWiFi System
The 802.11a specification includes the following restrictions:
Radio Band:
Maximum Data Rate:
Operating channels:
Maximum number of non-overlapping channels:
Typical Indoor Range
Typical Outdoor Range (Line of Sight)
a. With basic antenna and maximum power level.
Radio
band
UNII-1
UNII-2
UNII-2
Extended
UNII-3
ISM
Figure 5. The UNII band with 24 non-overlapping channels
2.2.3

802.11n RF Modulation Standard

The 802.11n standard improves the reliability of communications, the predictability of
coverage, and the overall throughput. It uses the same frequency bands as 802.11b/g and
802.11a. This means that WLAN products based on the 802.11n standard can operate in
the 2.4 GHz band, the 5 GHz band, or both.
802.11n devices can use Multiple-Input, Multiple-Output (MIMO). This means that they can
use more than one radio chain to transmit and receive. The standard defines configurations
from one transmit and one receive radio chain (1x1) up to four transmit and four receive
radio chains (4x4). MIMO can be used in several ways:
• Spatial division multiplexing: A transmitter breaks down the signal stream into multiple
streams, and transmits the streams using multiple antennas spaced a short distance
apart. This creates a difference in the multipath images for each stream. The receiver can
therefore distinguish the individual streams and put them back together, thereby
increasing the overall data rate of the system.
7 September 2011 / Ver. G
a
:
Frequency Number of
range (GHz) channels
5.15–5.25 4
5.25–5.35 4
5.47–5.710 11
5.725–5.825 4
5.825–5.875 1
5 GHz
54 Mbps
36–165 (depending on country
regulations), see the table below
19–24 (depending on country
regulations)
ETSI: 19
FCC: 24
30 m / 100 ft
a
: 100 m / 330 ft
Channel numbers
36, 40, 44, 48
52, 56, 60, 64
100, 104, 108, 112, 116, 120,
124, 128, 132, 136, 140
149, 153, 157, 161
165
TD 92313EN
FCC ETSI
X X
X X
X X
X
X
9