It is well known that the ionosphere can be highly disturbed in the auroral and polar cap regions. However, efforts to quantify ionospheric effects on high-frequency communications have concentrated mainly on lower-latitude regions. The Doppler and multipath sounding network (DAMSON) has been used in an extensive campaign to measure the channel characteristics on four paths in the auroral region of northern Scandinavia. The conditions observed indicate that robust data modems, used when less-robust, higher-rate modems fail, are required up to 90% of the time. A detailed analysis of the propagation parameters indicates that these modems, designed to operate in these regions, should be able to operate when the Doppler spread exceeds 40 Hz and the multipath spread is greater than 11.5 ms. Multiple propagation modes are common, especially between the lowest and maximum usable frequencies. The distribution of the received signal power in these cases is examined, and it is concluded that laboratory simulations used for robust-modem evaluation should include channel models with dominant modes.
References
-
-
1)
-
R.D. Hunsucker
.
Auroral and polar-cap ionospheric effects on radio propagation.
IEEE Trans. Antennas Propag.
,
7 ,
818 -
828
-
2)
-
E.M. Warrington ,
T.B. Jones ,
B.S. Dhanda
.
Observations of Doppler spreadingon HF signals propagating over high latitude paths.
IEE Proc. Microw. Antennas Propag.
,
4 ,
215 -
220
-
3)
-
Willink, T.J.: `Analysis of high-latitude HF propagation characteristics and their impactfor data communications', 97-001, CRC Report, 1997, available from www.crc.ca/library/Pub/crcrpt.htm..
-
4)
-
Hand, G.: `Ionospheric communications enhanced profile analysis and circuit predictionprogram', 1997.
-
5)
-
Willink, T.J.: `Modal power considerations in modem performance evaluation', Proceedings of Nordic HF, August 1998, Fårö, Sweden.
-
6)
-
K. Davies
.
(1990)
Ionospheric radio.
-
7)
-
Davies, N.C., Cannon, P.S.: `DAMSON – a system to measure multipath dispersion,Doppler spread and Doppler shift on multi-mechanism communications channels', AGARD Electromagnetic Wave Propagation Panel symposium on Multiplemechanism propagationpaths (MMPPs): Their characterisation and influence on system design, 4–7 Oct. 1993, Rotterdam, Netherlands.
-
8)
-
Wagner, L.S., Goldstein, J.A., Meyers, W.D., Bello, P.A.: `The HF skywavechannel: Measured scattering functions for midlatitude and auroral channels and estimates forshort-term wideband HF rake modem performance', Proc. IEEE Mil. Comm. conference, Oct. 1989, Boston, MA, USA, no. 48.2.
-
9)
-
M.J. Angling ,
P.S. Cannon ,
N.C. Davies ,
T.J. Willink ,
V. Jodalen ,
B. Lundborg
.
Measurements of Doppler and multipath spread on oblique high latitudeHFpaths and their use in characterising data modem performance.
Radio Sci.
,
1 ,
97 -
107
-
10)
-
Bröms, M.: `DAMSON antennas', FOA-D--98-00360-504-SE, Report, January 1998.
-
11)
-
R.H. Holzworth ,
C.-I. Meng
.
Mathematical representation of the auroral oval.
Geophys. Res. Lett.
,
9 ,
377 -
380
-
12)
-
Moreland, K.W., Willink, T.J., Venier, G.O., Cannon, P.S., Davies, N.C., Angling, M.J., Jodalen, V., Lundborg, B.: `Comparison of mid-latitude and high-latitudeHF channel measurements of Doppler and multipath effects', Proceedings of 7th international conference on WirelessCommunications, July 1995, Calgary, AB, Canada.
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