2011 International Conference on Advanced Technologies for Communications (ATC 2011)
Vietnam Spectrum Occupancy Measurements and
Analysis for Cognitive Radio Applications
Vo Nguyen Quoc Bao∗ , Le Quoc Cuong∗ , Le Quang Phu∗ , Tran Dinh Thuan∗ ,
Nguyen Thien Quy† , Lam Minh Trung†
∗ School
of Telecommunications
Posts and Telecommunications Institute of Technology
Email: {baovnq, lequoccuong, phulq, tdthuan}@ptithcm.edu.vn
† Radio Frequency Directorate
Vietnam Ministry of Information and Communications
Email: {thienquy, trunglm}@rfd.gov.vn
Abstract—The rapid growth of demand for wireless transmission has placed great pressure on the scarce radio spectrum due
to the fixed spectrum allocation policy and cognitive radio (CR)
is considered as a promising solution to such the problem. The
main idea behind a cognitive radio network is for the unlicensed
users (also called secondary users) to exploit opportunistically the
underutilized spectrum licensed to a licensed network (referred
to as a primary network). Before investigating the technical and
political implications of CR, it is important to know to what
extent the licensed bands are temporally unoccupied. In this
paper, for the first time, we investigate the spectrum usage pattern
in Vietnam in the frequency bands ranging from 20 MHz to
3000 MHz in Ho Chi Minh City and Long An province. The
purpose of the measurement is to find how the scarce radio
spectrum allocated to different services is utilized in Vietnam and
identify the bands that could be accessed for future opportunistic
use due to their low or no active utilization. These analyses
indicate that, on average, the actual spectral usage in all bands
is 13.74% and 11.19% for Ho Chi Minh City and Long An
province, respectively. The experiment results also show that the
spectrum band assigned for analog television (470-806) is the
highest occupancy band with 58%.
I. I NTRODUCTION
Radio frequency spectrum is a resource of fundamental
importance in wireless communication systems. During recent
years, a multitude of wireless applications and services has
been developed resulting in a collision with the comprehensive, well-established, but increasingly obsolescent policy
for the allocation and utilization of the radio spectrum [1].
In principle, international regulatory bodies like the Federal
Communications Commission (FCC) coordinate and properly
regulate the usage of radio spectrum resources and the regulation of radio emissions [2]–[4]. In Vietnam, based on the
recommendations of the FCC, the radio frequency directorate
(RFD) assigns spectrum to licensed holders, also known as
primary users, on a long-term basis [5]1 2 3 .
Such the policy partitions the overall radio spectrum into
non-overlapping frequency bands corresponding to different
purposes, i.e. government, public safety, national defense,
television radio, cellular, and unlicensed consumers. Although
the fixed allocation approach ensures that competing wireless
applications do not interfere with each other’s, it seems to
be inappropriate since the current spectrum use is inefficient
with some bands heavily subscribed and others rarely used.
One of the most promising solutions for such the problem is
cognitive radio, invented by Mitola [6], being able to detect
an unoccupied frequency band to use temporarily, and then
vacate when necessary [7]. To realize CR networks as well
as to quantify their potential benefits accurately, the current
spectrum usage should be known. Therefore, the crucial step
is the study of the availability of temporarily unoccupied
spectrum not only in terms of frequency but also in terms
time and space.
Till now, several measurement campaigns were conducted
in USA [8], New Zealand [9], Germany [10], Singapore [11],
China [12], Spain [13], and Qatar [14]. A shared finding
among these studies is that a large portion of the assigned
spectrum remains underutilized. In this paper, for the first time,
we report the detail results of a spectrum survey conducted
in Vietnam with an aim not only to fill the gaps today in
knowledge about the use of spectrum but also to identify the
most suitable and interesting bands for CRNs. The spectrum
measurement campaign covers the frequency range from 20
MHz to 3000 MHz in two locations: Ho Chi Minh City and
Long An province. The rest of this paper is organized as
follows. In section II, we introduce the measurement setup
and procedure. Section III presents the measurement results
and provides some observation and discussion. Finally, the
paper is closed in section IV.
II. M EASUREMENT S ETUP AND P ROCEDURE
The equipment used for the measurement consists of a set
of antenna, an R&S EM550 VHF / UHF digital wideband
receiver4 , and a server installed R&SARGUS monitoring
software5 . The set of antennas including HE0166 , HE3097 ,
4 http://www2.rohde-schwarz.com/product/em550.html
1 http://rfd.gov.vn/Danh
sach/Quy hoach moi
2 http://rfd.gov.vn/Danh+sach+Quy+hoach+bang+tan/Quy hoach bang tan
3 http://rfd.gov.vn/Danh sach/Quy
978-1-4577-1207-4/11/$26.00 ©2011 IEEE
135
5 http://www2.rohde-schwarz.com/product/ARGUS.html
6 http://www2.rohde-schwarz.com/product/HE016.html
7 http://www2.rohde-schwarz.com/product/HE309.html
HE015
HE309
HE314A1
HF214
HF902
Matrix Switch
Fig. 1.
The measuarement system.
Fig. 2.
HE314A18 , HF2149 and HF90210 is connected to the EM550
receiver via a switch matrix as shown in Fig. 1. Via the
R&SARGUS monitoring software, we can configure the system to measure the received signal power in all range of
frequency (of interest) from 20 MHz to 3000 MHz as well
as stored all the measurement results in the server in real
time for further processing. The detail characteristics of each
antenna are provided in Table I. Depending on the measured
spectrum band, the appropriate antenna is manually chosen,
i.e. it is directly connected to the receiver. For example, we
use an active vertical dipole (HE309) for the frequency range
between 20MHz to 1300 MHz while HF902 should be used
if the frequency range from 1 to 3 GHz is considered.
The measurements were conducted over a 4-month time
span from Oct. 2010 to Feb. 2011 at two different locations.
The first location as shown in Figs. 2 is the roof top (the 6th
floor) of the RFD office building in An Phu, District 2, Ho Chi
Minh City with coordinate 10◦ 47 42.3 and 106◦ 44 25.9 . As
a reference, the second location (Long An province with coordinate 10◦ 38 12.50 and 106◦ 29 36.00 ) is chosen roughly
50km far away the first location considered as a rural area.
Both the chosen measurement sites almost have almost no
high buildings surrounding enabling us to accurately measure
the spectral activity of all possible transmitters.
The utilization of spectrum is usually quantitatively examined by the most used metric - spectrum occupancy. In
a particular location, it is defined as the probability that a
measured signal of a certain bandwidth is unused by primary
users. To determine whether a given frequency is occupied
or not, spectrum sensing is usually used. There are three
common methods proposed in the literature so far including
matched filter detection, cyclostationary feature detection and
energy detection [15], [16]. Among them, energy detection is
the most popular method measuring only the received signal
8 http://www2.rohde-schwarz.com/product/HE314A1.html
9 http://www2.rohde-schwarz.com/en/products/antennas/HF214.html
10 http://www2.rohde-schwarz.com/en/products/antennas/HF902.html
The measurement system.
Fig. 3.
The antenna system.
power [17]. In this paper, we use the energy detection for
all measurements. In energy detection approach, a frequency
band is considered ”unused” if the power of measured signals
is above a predefined power threshold, i.e. the noise level
at the receiver. Otherwise, it is reported as an ”available”
band for cognitive applications. Therefore, determining the
level of background noise is a critical step towards spectrum
occupancy measurement. According to [2], [10], [14], a margin
of 3dB is considered for determining the final threshold value
in order to account any unforeseen effects and variations.
III. M EASUREMENT R ESULTS AND A NALYSIS
In this section, we present some selective spectral measurement results. We start with the Fig. 5 and 6 where the average
PSD over the whole frequency range of measurement study
are plotted. Due to the characteristics of the antennae used,
the measured frequency is divided into two non-overlapping
136
Fig. 4.
The aerial map showing Ho Chi Minh City measurement site
(Courtesy of Google Inc.).
Type of antenna
HE016
HE309
HE314A1
HF214
HF902
Antenna characteristics
Active antenna system, omnidirectional reception of vertically and horizontally polarized signals with bandwidth
10 kHz to 80 MHz (vertical) and 600 kHz to 40 MHz
(horizontal).
Active vertical dipole, high sensitivity, large bandwidth
and wide dynamic range from 20MHz to 1300 MHz.
Active omnidirectional antenna, reception of horizontally
polarized waves from 20 MHz to 500 MHz.
Omnidirectional antenna, designed for the reception of
horizontally polarized waves 500 MHz to 1300 MHz.
Omnidirectional antenna designed for the reception of
vertically and horizontally polarized waves from 1-3
GHz.
TABLE I
A NTENNA CHARACTERISTICS .
0
PSD [dBm]
−20
−40
−60
−80
−100
100
200
300
400
500
600
Frequency [MHz]
700
800
900
1000
Fig. 5. Average power spectral density vs. frequency at Ho Chi Minh City
20-1000 MHz.
0
PSD [dBm]
−20
−40
−60
−80
−100
1000
1200
1400
1600
1800
2000
2200
Frequency [MHz]
2400
2600
2800
3000
Fig. 6. Average power spectral density vs. frequency at Ho Chi Minh City
1000-3000 MHz.
frequency ranges, i.e. from 20 to 1000 Mhz and from 1001
MHz to 3000 MHz. From the figures, there are some important
points that is worth noting as follows. The level of background
noise is a little higher than the theoretical ambient noise.
Importantly, it is not constant and slightly increases with
frequency resulting in an increase on the decision threshold.
It is due to the fact that the decision threshold is chosen 3-dB
above the system noise floor as mentioned previously. Besides,
we can also observe that the actual spectrum usage pattern
is not uniform, i.e, the spectrum below 1 GHz seems to be
heavily utilized while the spectrum from 2 to 3 GHz is found
to be lightly used.
Although Fig. 5 and 6 provide us some overview about
spectrum utilization, they is insufficient to provide a detail
description on how spectrum is used in different bands. Therefore, for a better view, we participate the overall spectrum
under consideration into 15 sub-bands and study its associated
spectrum activity in Figs. 7-22. In particular, Fig. 7, 8 and 9
show the received power versus frequency plot for 30-54 MHz,
54-68 MHz and 68-87 MHz, respectively. Clearly observed
from the figures, the band allocated to FM radio is found to
be most quiet as compared to the other bands.
In Fig. 10, 12 and 15, we show the PSD in the broadcasting
(FM, TV) bands: 87-108 MHz, 174-230 MHz and 490-806
MHz. As can be seen, they are the most heavily utilized bands
observed in this study. The typical maximum signal power of
FM bands is from 0 dBM to -20 dBm. With TV channels,
the maximum power is around -60dBm to -40 dBm. From the
figures, we can also identify some spectrum of signals coming
from some popular FM and TV channels, e.g. VOV1, VOV2,
VOV3, VOV5, FM99.9 , HTV7, HTV9, TayNinh, DongNai,
etc.
Along with the broadcasting bands, cellular mobile service
bands (Fig. 14, 16 and 21) are the other ones having a
considerably higher occupancy rate compared with other type
of frequency allocations. If we consider land mobile bands
824-960 MHz and 1710-2300 MHz, it is easy to identify the
spectrum of downlink GSM/E-GSM signals that are located in
950MHz and 1800MHz bands. Furthermore, the spectrum of
downlink 3G/IMT2000 signals of four 3G service providers,
i.e. Mobile, Viettel, EVN&HT, and Vinaphone, are observed
ranging from 2110Mhz to 2200 MHz. It appears that the
downlink channels in point-to-multipoint mobile applications
are identified as mostly occupied. This is due to the active
control channels constantly broadcasted by base stations to
maintain cellular service coverage of GSM900, GSM1800
and WCDMA networks. Unlike downlink channels always
transmitting with relatively high power, the usages in the
uplink channels depend on the actual number of active mobile
users in the measurement area and more intermittent according
to their behaviors. From the figure, we can see that as expected
transmit power of GSM900 mobile stations is higher than
that of GSM1800 mobile stations. Besides, from Fig. 21, we
also observe that 3G uplink channels seem to be completely
unused. Here, it should be noted that due to the nature of
WCDMA technology the transmit power of uplink channels
137
in 3G system is very low, and might not be detectable by the
measurement system.
Next, we focus on Fig. 11 and 13 where the spectrum
activity of the frequency bands 108-174 and 230-406 is shows.
As can be seen, most part of these bands band is unoccupied
suggesting some opportunities for cognitive radio accesses.
However, recalling that the whole band from 230 to 406 MHz
is exclusively reserved for security services and systems of
the Vietnam ministry of public security (MPS). Therefore,
in principle, such spectrum bands should be precluded by
secondary access.
The average PSD of the well-known unlicensed Industrial,
Scientific and Medical (ISM) band (2400 to 2500 MHz) is
illustrated in Fig. 22. Allocated for unlicensed spectrum use,
the ISM band is considered as the most open band. Within
this band, many wireless applications are operated including
WiFi transmitters, cordless telephones, microwave ovens, and
various consumer products. Therefore, it is believed to be the
most heavily used frequency band. However, from Fig. 22,
it is observed that this band appears to be unoccupied. It
can be explained by the fact that this frequency band is
usually occupied in indoor environments and signals at such
frequencies are severely attenuated by walls. The rest of
spectrum between and 3 GHz remains mostly unused, with
the exception of some signals with very low duty cycle
in bands allocated to aeronautical and satellite radiolocation
and radionavigation, (960-1350 and 1610-1710 MHz), DECT
cordless phones (1880-1900 MHz) and military radars (27002900 MHz).
To this end, we show the band-by-band average spectrum
occupancy in Ho Chi Minh City in Fig. 23. The results of these
measurements indicate that some spectrum bands are subjected
to exhaustive usage while some others are sparsely used or
show temperate utilization, and, in some cases, are not used
at all. In general, the average spectrum occupancy observed in
Ho Chi Minh City is 13.74% for the whole frequency range
between 20MHz and 3000 MHz and the band assigned for
television broadcasting is the highest occupancy band with
58%. Stated another way, 86.25% of this spectrum is unused.
As a baseline for comparison, we also show the average
spectrum occupancy of New York and Long An in Fig. 24. The
obtained results demonstrate that Ho Chi Minh City spectrum
utilization exceeds Long An by roughly 1.46%, which, in
turns, exceeds New Yorks by 1.15%.
IV. C ONCLUSION
The spectrum measurements presented here are part of a
larger on-going measurement campaign conducted by PTIT in
several cities in the south of Vietnam. The purpose of this
project is to create a usage map for cognitive applications
in Vietnam. The challenge of this campaign is not only
cost (equipment) but also time (deployment) where multiple
locations are to be measured to obtain local spectral pattern
usage.
Our measurement results suggest that in Vietnam most of
allocated frequencies are underutilized except for mobile and
broadcasting bands and CR applications can be realized by exploiting bands with low measured occupancy rates. However,
care must be taken to account for possible wireless channel
effects such as multi-path and hidden terminal problems.
ACKNOWLEDGMENT
This research was supported in part by the Science and
Technology Foundation of Ho Chi Minh City and by the
Vietnam’s National Foundation for Science and Technology
Development (NAFOSTED) (No. 102.99-2010.10).
R EFERENCES
[1] Computer Science and Telecommunications Board, Wireless Technology
Prospects and Policy Options. National Academy of Sciences, 2011.
[Online]. Available: http://www.nap.edu/catalog.php?record id=13051#
toc
[2] R. Bureau, “Handbook on spectrum monitoring,” International Telecommunication Union (ITU), p. 168, 2002.
[3] OFCOM, “United kingdom frequency allocation table,” 2010. [Online].
Available: http://tinyurl.com/44j8vpf
[4] NTIA, “United states frequency allocations: The radio spectrum,” 2010.
[Online]. Available: http://www.ntia.doc.gov/osmhome/allochrt.pdf
[5] L. V. Tuan, “Radio frequency management in vietnam,” Journal on
Information & Communications Technologies, 2008. [Online]. Available:
http://www.tapchibcvt.gov.vn/vi-vn/sanphamdichvu/2007/8/18328.bcvt
[6] I. Mitola, J. and J. Maguire, G. Q., “Cognitive radio: making software
radios more personal,” IEEE Personal Communications, vol. 6, no. 4,
pp. 13–18, 1999.
[7] J. Wang, M. Ghosh, and K. Challapali, “Emerging cognitive radio
applications: A survey,” IEEE Communications Magazine, vol. 49, no. 3,
pp. 74–81, 2011.
[8] M. A. McHenry, “Nsf spectrum occupancy measurements project summary,” Shared Spectrum Co., Tech. Rep., Aug. 2005.
[9] R. I. C. Chiang, G. B. Rowe, and K. W. Sowerby, “A quantitative
analysis of spectral occupancy measurements for cognitive radio,” in
Proc. IEEE VTC2007-Spring Vehicular Technology Conf. (IEEE VTC
65th, pp. 3016–3020.
[10] M. Wellens, J. Wu, and P. Mahonen, “Evaluation of spectrum occupancy
in indoor and outdoor scenario in the context of cognitive radio,” in
Proc. 2nd Int. Conf. Cognitive Radio Oriented Wireless Networks and
Communications CrownCom 2007, pp. 420–427.
[11] M. H. Islam, C. L. Koh, S. W. Oh, X. Qing, Y. Y. Lai, C. Wang, Y.-C.
Liang, B. E. Toh, F. Chin, G. L. Tan, and W. Toh, “Spectrum survey in
singapore: Occupancy measurements and analyses,” May 2008.
[12] D. Chen, S. Yin, Q. Zhang, M. Liu, and S. Li, “Mining spectrum usage
data: a large-scale spectrum measurement study.” ACM, pp. 13–24.
[13] M. Lpez-Bentez, A. Umbert, and F. Casadevall, “Evaluation of spectrum
occupancy in spain for cognitive radio applications.” IEEE, pp. 1–5.
[14] K. A. Qaraqe, H. Celebi, A. Gorcin, A. El-Saigh, H. Arslan, and M.s. Alouini, “Empirical results for wideband multidimensional spectrum
usage,” in Proc. IEEE 20th Int Personal, Indoor and Mobile Radio
Communications Symp., pp. 1262–1266.
[15] A. Goldsmith, S. A. Jafar, I. Maric, and S. Srinivasa, “Breaking spectrum
gridlock with cognitive radios: An information theoretic perspective,”
Proceedings of the IEEE, vol. 97, no. 5, pp. 894–914, 2009.
[16] A. Ghasemi and E. S. Sousa, “Spectrum sensing in cognitive radio networks: requirements, challenges and design trade-offs [cognitive radio
communications],” IEEE Communications Magazine, vol. 46, no. 4, pp.
32–39, 2008.
[17] F. F. Digham, M. S. Alouini, and M. K. Simon, “On the energy
detection of unknown signals over fading channels,” IEEE Journal on
Communications, vol. 55, no. 1, pp. 21–24, 2007.
138
Amateur
PSD [dBm]
0
Mean
Min
Max
−50
−100
30
35
40
Frequency [MHz]
Fig. 7.
45
50
Amateur 30-54 MHz.
FM radio
PSD [dBm]
0
Mean
Max
Min
−50
−100
54
56
58
60
F
Fig. 8.
62
[MH ]
64
66
68
Broadcasting (FM radio) 54-68 MHz.
Aero Nav., Analog TV.
PSD [dBm]
0
Mean
Max
Min
−50
−100
68
70
72
74
Fig. 9.
76
78
Frequency [MHz]
80
82
84
86
Aeronautical Radionavigation/Analog TV 68-87 MHz.
FM radio
PSD [dBm]
0
Mean
Max
Min
−50
−100
88
90
92
94
Fig. 10.
96
98
Frequency [MHz]
100
102
104
106
108
Broadcasting (FM radio) 87-108 MHz.
Aero, Mobile, Radio Nav., Maritime, Amateur, PMR
PSD [dBm]
0
Mean
Max
Min
−50
−100
110
Fig. 11.
120
130
140
Frequency [MHz]
150
160
170
Aeronautical Radionavigation, Aeronautical Mobile (R), Mob. Sat. (S-E)/Fixed/Mobile, Amateur/Amateur Satellite, Fixed/Mobile 108-174 MHz.
139
Analog TV
0
PSD [dBm]
Mean
CH9:HTV9
CH7:HTV7
Min
CH11:
TAYNINH
Max
CH12:
DONGNAI
−50
−100
175
180
185
190
Fig. 12.
195
200
205
Frequency [MHz]
210
215
220
225
230
Broadcasting (TV channels 7 to 13) 174-230 MHz.
Fixed mobile, Aero, Others
Data
Transmisson
of MPS
PSD [dBm]
0
−50
−100
240
260
280
Fig. 13.
PSD [dBm]
320
Frequency [MHz]
340
360
380
400
Fixed/Radionavigation Sat./Meteorological Aids 230-406 MHz.
Amatuer, fixed, mobile, radiolocation
DOWNLINK
PMR
TAXI
UPLINK
PMR
TAXI
0
300
CDMA
400/EVN
Mean
Min
Max
−50
−100
410
420
430
Fig. 14.
440
Frequency [MHz]
450
PSD [dBm]
CH21 CH22 CH23
470
Fixed/Radiolocation/Land Mobile 406,1-470 MHz.
Broadcasting
0
460
CH25 CH26
CH30
CH28
CH32
Mean
CH34
CH36
Max
Min
CH39 CH40 CH41 CH42
−50
−100
480
PSD [dBm]
0
CH44
500
520
CH48
540
560
580
Frequency [MHz]
CH50 CH51 CH52
600
CH54 CH55 CH56
620
CH60
640
CH62
−50
−100
650
700
750
Frequency [MHz]
Fig. 15.
Broadcasting (TV channels 14 to 20)/Fixed 470-806 MHz.
140
800
DL
DL
DL
DL
E−GSM GSM GSM
GSM
VNMOB VINA VIETEL MOBI
Mobile Data, PMR & Trunking
UL
CDMACDMA
S−PHONEE−GSM
VNPT
UL
GSM
−50
Mean
Min
Max
−100
820
840
860
880
900
Frequency [MHz]
Fig. 16.
920
PSD [dBm]
−55 DME
1003
940
960
Fixed/Land mobile 810-960 MHz.
Mean
DME
DME 1024
DME 1201
Min
Max
DME 1260 DME 1280
DME 1340
−60
−65
−70
1000
1050
1100
Fig. 17.
1150
1200
Frequency [MHz]
1250
1300
1350
Aeronautical Radionavigation 960-1350 MHz.
Radio Location, Radio Astronomy, Earth Exploration Sat., Space Research
PSD [dBm]
0
Mean
Min
Max
−20
−40
−60
1350
1360
1370
Fig. 18.
1380
1390
Frequency [MHz]
1400
1410
1420
Radio location/Earth Expl. Sat./Radio Astronomy 1350-1427.
Fixed
−50
PSD [dBm]
PSD [dBm]
0
VIBA VNPT
1470.5 MHz
−55
Mean
Min
Max
−60
1430
1440
1450
1460
Fig. 19.
1470
1480
Frequency [MHz]
Fixed 1427-1525 MHz.
141
1490
1500
1510
1520
Mobile Sat., Radio Astronomy, Meteorological Sat., Space Research, Fixed
PSD [dBm]
−40
−60
1560
1580
1600
1620
1640
Frequency [MHz]
Fig. 20.
0
PSD [dBm]
Maritime Mobile Satellite
(Earth to Space)
Maritime Mobile Satellite
(Space to Earth)
−50
1540
1660
1700
Mean
GSM1800 (BT)
Vina
Mobile Vietel GTel
1680
Mobile Satellite 1525-1660,5 MHz.
GSM1800 (BR)
Vina
Max
Min
Mobile Vietel GTel
−20
−40
−60
−80
1750
1800
0
PSD [dBm]
Mean
Min
Max
Mobile Satellite
1850
Frequency [MHz]
1900
1950
2000
IMT2000
−20
−40
−60
2000
2050
Fig. 21.
2100
2150
Frequency [MHz]
2200
2250
2300
Radio Astronomy/Space Research/Meteological Aids/Mobile/Fixed 1710-2300 MHz.
ISM, Radio Location, Maritime Radionavigation,
Aeronautical Radionavigation, Meteorological Aids.
PSD [dBm]
0
Mean
Min
Max
−20
−40
2300
2400
Fig. 22.
2500
2600
2700
Frequency [MHz]
2800
Fixed/Mobile/Aeronatical navigation/Radiolocation 2300-3000 MHz.
142
2900
3000
Amateur 30−54 MHz
Broadcasting (FM radio) 54−68 MHz
Aeronautical Radionavigation/Analog TV 68−87 MHz
Broadcasting (FM radio) 87−108 MHz
Aeronautical Radionavigation 108−117,975 MHz
Aeronautical Mobile (R) 117,975−137 MHz
Mob. Sat. (S−E)/Fixed/Mobile 137−144 MHz
Amateur/Amateur Satellite 144−146 MHz
Fixed/Mobile 146−174 MHz
Broadcasting (TV channels 7 to 13) 174−230 MHz
Fixed/Radionavigation Sat./Meteorological Aids 230−406,1 MHz
Fixed/Radiolocation/Land Mobile 406,1−470 MHz
Broadcasting (TV channels 14 to 20)/Fixed 470−806 MHz
Fixed/Land mobile 806−824 MHz
Land Mobile/Fixed 824−960 MHz
Aeronautical Radionavigation 960−1350 MHz
Radio location/Earth Expl. Sat./Radio Astronomy 1350−1427 MHz
Fixed 1427−1525 MHz
Mobile Satellite 1525−1660,5 MHz
Radio Astronomy/Space Research/Meteological Aids/Fixed 1660,5−1710 MHz
GSM/Fixed 1710−2300MHz
Fixed/Mobile/Aeronatical navigation/Radiolocation 2300−3100 MHz
0
Fig. 23.
30−54 MHz
54−88 MHz
108−138 MHz
138−174 MHz
174−216 MHz
216−225 MHz
225−406 MHz
406−470 MHz
470−512 MHz
512−608 MHz
608−698 MHz
698−806 MHz
806−902 MHz
902−928 MHz
928−906 MHz
960−1240 MHz
1240−1300 MHz
1300−1400 MHz
1400−1525 MHz
1525−1710 MHz
1710 1850 MHz
1850−1990 MHz
1990−2110 MHz
2110−2200 MHz
2200−2300 MHz
2300−2360 MHz
2360−2390 MHz
2390−2500 MHz
2500−2686 MHz
2686−2900 MHz
2900−3000 MHz
10
20
30
40
50
60
Average spectrum occupancy by band Ho Chi Minh City.
Ho Chi Minh City
Long An
New York
0
10
Fig. 24.
20
30
40
50
60
70
Average spectrum occupancy by band Ho Chi Minh City vs. Long An vs. New York.
143
80