Network Management Strategies for the CIO
Practical applications include radiolinks in offices and factory buildings, production and laboratory floors covering one or multiple stories. Connectivity may also wish to be extended campus-wide. Here we mean that communication may also be desired over and around several buildings and adjacent properties. IEEE 802.16 documentation gives the maximum bit rate supported as 155 Mbps. Let us assume a receiver noise figure of 5 dB and transmitter output power of 2.0 W or +6 dBW, transmission
Requires Free Membership to View
line losses of
3 dB and an antenna gain of 0 dBi, what kind of performance can we
expect on an
LOS path 1 km distant? The model link is
set out in a tabular form beginning with the transmitter power output
placed at
the top of the column. The abbreviation RSL
means the "receive signal level." This
term is widely used on RF systems. RSL
is conventionally measured in dBW or dBm.
We also establish a performance requirement expressed as BER at 1X10-10. where the Eb/No = 17 dB including 2 dB of modulation implementation loss.
Eb/No is energy per bit (Eb) per noise density ratio (No). In our table below Eb = RSL divided by the bit rate. No = thermal noise in 1 Hz of bandwidth and is calculated as –204 dBW + 10Log(noise figure). The noise figure of the model receiver is 5 dB, then No = -204 dBW + 5 dB = -199 dBW/Hz.
Model outdoor-indoor link power budget
| ITEM |
PARAMETER
VALUE |
COMMENTS |
| Transmitter
power output |
+6 dBW |
4 W equiv. |
| Trans line
losses |
-3 dB |
Approx |
| Trans ant
gain |
0 dBi |
|
| EIRP |
+3 dBW |
|
| LOS free
space loss at 1 km, @ 2.5, 5.2 GHz |
-100.36 dB
(2.5 GHz) -106.72 dB (5.2 GHz) |
|
| Rec ant gain |
0 dBi |
|
| Miscl line
losses |
-3 dB |
|
| Rec signal
level (RSL) |
-97.36 dBW |
@2.5 GHz |
| Rec signal
level (RSL) |
-103.72 dBW |
@5.2 GHz |
| Link bit rate |
155x106
bps |
81.9 dB equiv |
| Eb,
(RSL = -106.36 dBW) Eb (RSL = -112.72 dBW) |
-179.26 dBW -185.62 dBW |
@2.5 GHz @5.2 GHz |
| Eb/No |
19.74 dB
(2.5 GHz) 13.38 dB (5.2 GHz) |
No=
-199 dBW/Hz |
| No
= -199 dBW/Hz |
FSL = 32.4 + 20Log2500 = 32.4 + 67.96 = 100.36 dB at 1 km, 2.5 GHz
32.4 + 20log5200 = 106.72 dB at 1 km, 5.2 GHz
About the author:
Roger Freeman has worked in telecommunications since 1946 when he joined the Navy and became an aviation radioman. Later, Roger served as a radio officer in the merchant marine for nearly 10 years. He then held several positions with ITT assigned to their Spanish Standard Electrica subsidiary. He also served the International Telecommunication Union as Regional Planning Expert for Northern Latin America based in Quito, Ecuador. Roger is bilingual. His last employee position was principal engineer with the Raytheon Company, Marlboro, MA where he took early retirement in 1991 to establish Roger Freeman Associates, Independent Consultants in Telecommunications. He has been giving seminars in telecommunication disciplines at the University of Wisconsin, Madison for nearly 20 years. Roger has been writing books on various telecommunication subjects for John Wiley & Sons since 1973. There are seven titles which he keeps current including the two-volume work, Reference Manual for Telecommunication Engineers, now in 3rd edition. He holds two degrees from NYU. His Web site is www.rogerfreeman.com and his e-mail address is rogerf67@cox.net.
This was first published in December 2004
Join the conversationComment
Share
Comments
Results
Contribute to the conversation