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Vietnam Posts and Telecommunications Group
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VNPT-VINAPHONE
UMTS 900 REFARMING
Doctor. Do Vu Anh
Director of Telecoms Division – VNPT Group
3/2015
Beautiful
Content
1.  UMTS900 refarming
2.  Vinaphone UMTS900 refarming
3.  Recommendations
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UMTS 900 refarming
• 
Some of the benefits of deploying 900 compared to
UMTS 2100MHz:
• 
• 
Radio path loss is much lower ;
• 
• 
• 
• 
Saving CAPEX and OPEX costs;
• 
The ability to use the infrastructure to existing GSM 900 networks
deployed rapidly UMTS900 (co-site), reused cabinets, hardware, power,
backup system, antena, transmission;
Better coverage , the number of stations required to be lower than the
2100 MHz;
Re-use Network Management;
Reduce operational complexity;
Allows better indoor coverage in urban areas lead to better service
quality and customer satisfaction;
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UMTS 900 refarming
• 
Compared to 3G 2100Mhz:
ü Compare to 3G 2100Mhz,
50%-70% reduction in
CAPEX, OPEX;
ü Reduce the number of site;
ü Net Present Value (NPV)
increased;
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UMTS 900 refarming
Radio spectrum usage
Coverage area
increased more
than 3 times
higher than 3G
2100Mhz
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UMTS 900 refarming
• 
Compared to 3G 2100Mhz:
Voice Service:
Area coverage
3G900 Voice
service increased
3 times higher
than 3G2100
UMTS forum
and 5,8x more
than GSM1800;
and 1,5x more
than GSM900
voice service;
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UMTS 900 refarming
• 
• 
Indoor coverage :
Especially the speed and coverage of the increased of 900MHz compared
to 2100 Mhz, as follows :
Data service:
Outdoor:
3G900: 5,2 Mbps
3G2100: 4,5 Mbps
Indoor (-10dB penetration
loss):
3G900: 3,4 Mbps
3G2100: 2,0 Mbps
Indoor (-20dB penetration
loss):
3G900: 1,2 Mbps
3G2100: 0,5 Mbps
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UMTS 900 refarming
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UMTS 900 refarming
Most HSPA mobile broadband networks operate in the 3G/2100 MHz band, except in the Americas where 1900 and 850 MHz dominate.
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UMTS 900 refarming
• 
Frequency
management as
decided by the
Ministry of
Information and
Communications
VietNam:
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Vinaphone U900 refarming
• 
Interference :
v 
UMTS NodeB to
GSM UE interference
v 
GSM UE to UMTS NodeB
interference
v 
UMTS UE to GSM BTS
interference
v 
GSM BTS to UMTS UE
interference
Interference between NodeB and BTS
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Vinaphone U900 refarming
• 
Interference (con’t):
• 
Using Sandwich freq
solution to prevent
interference to other
mobile operators;
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Vinaphone U900 refarming
• 
Interference (con’t):
• 
Use BufferZone
against interference
between GSM900
and UMTS900
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Vinaphone U900 refarming
• 
• 
Interference (con’t) :
• 
Perform frequency hopping, implement appropriate
power control;
• 
Using buffers (buffer zone ) against interference;
Using the solution increases capacity as HR, AMR,
OSC, VAMOS, in addition to increased capacity allows
GSM 900 system, significantly reduces interference to
UMTS900;
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Vinaphone U900 refarming
• 
• 
The efficiency of frequency:
• 
Practice in VNPT- Vinaphone shows that : Effective spectrum
approximately : 0.7 bit / s / Hz ;
According to 3GPP: with 900 UMTS networks , using technology to
deploy HSPA + UTMS900 have bandwidth efficiency gain 0,74bit / s / Hz ,
compared to GSM 0.04 bits / s / Hz ie efficiency 18 times ;
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Vinaphone U900 refarming
Load balancing between GSM900 and GSM1800 in a
dualband GSM network in order to refarm part of
GSM900 spectrum for UMTS900 deployment:
n  Traffic from current 2G 900M network can be distributed to GSM1800 and/or UMTS900M. While for the user with 2G only handset, traffic will go to GSM1800M in order to balance the traffic and avoid congesNon over the 900M network. n  In a long run, UMTS traffic will go up along with the declining of total GSM capacity
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Vinaphone U900 refarming
BUILDING
PENETRATION
LOSSES
KEY BENEFITS
•  30% better indoor penetration
•  Applicable for urban & rural
2100 VS. 900
COVERAGE
COMPARISON
KEY BENEFITS
•  Better coverage due to different propagation losses
•  Either half number of rural sites
•  Or higher capacity in urban with same number of sites
HSDPA
THROUGHPUT
KEY BENEFITS
•  At least 20% more HSDPA throughput in urban and rural
VOICE CELL
COVERAGE
W-CDMA900 /
GSM900
KEY BENEFITS
•  Reuse GSM900 sites for W-CDMA900
•  Cheaper deployment
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Vinaphone U900 refarming
1.  UMTS900 will be deployed by reusing the GSM sites within
the existing service area, and benefits will also be gained
because of:
• reuse of the existing base station sites
• reuse of the existing antenna systems and feeders
2. 
From a practical implementation point of view, operators
only need either to add a new base station cabinet or to
replace the existing GSM base station by a multimode GSM
+UMTS base station subject to site situation or
manufacturer’s design.
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Vinaphone U900 refarming
1.  Tests showed greater coverage radius of 2 times the 3G
2100MHz ;
2.  Against interference between U900 and GSM900 for hightraffic areas required to use bufferzone or add more stations
GSM1800;
3.  Deploying U900 frequency design suitable for traffic load
balancing between 2G900 and 3G900;
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Thank you!
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