impact of second carrier in 3g
TRANSCRIPT
Ting-Huei Lin, Ph.D.Email: [email protected]
Senior Engineer
Mobile Business Group, Chunghwa Telecom Co., Ltd.
Impact on the Capacity and Performance
with the Implementation of a Second
Carrier in 3G Network
3/20
Taiwan population
Mobile Market in Taiwan
Highly competitive mobile market
� Many systems and operators within 36,000 km2
� Penetration rate is more than 100%.
GSM/WCDMA is the dominant system.
All WCDMA systems had launched HSDPA service.
GSM WCDMA WCDMA WCDMA WCDMA HSPAHSPAHSPAHSPAcdmacdmacdmacdma
2000200020002000PHSPHSPHSPHS WiMaxWiMaxWiMaxWiMax
CHT VFDD:2x15MFDD:2x15MFDD:2x15MFDD:2x15M
TDD: 5MTDD: 5MTDD: 5MTDD: 5MV - - -
TWN VFDD:2x15MFDD:2x15MFDD:2x15MFDD:2x15M
TDD: 5MTDD: 5MTDD: 5MTDD: 5MV - - -
FET VFDD:2x15MFDD:2x15MFDD:2x15MFDD:2x15M
TDD: 5MTDD: 5MTDD: 5MTDD: 5MV - - v
VIBO -FDD:2x10MFDD:2x10MFDD:2x10MFDD:2x10M
TDD: 5MTDD: 5MTDD: 5MTDD: 5MV - - -
APBW - - - 2x20M2x20M2x20M2x20M - -
FITEL - - - - v -
…+5 - - - - - v
Operator
System
4/20
Chunghwa Telecom Mobile
CHT- the largest integrated telecom operator in Taiwan
� Fixed, mobile, Internet, satellite, …
The largest mobile operator in Taiwan
� Subscribers > 9.2 millions
� Mobile market shares 34%
GSM900/1800 & WCDMA/HSPA network
Subsc
ribers
(m
illi
n)
Source: NCC
5/20
CHT 3G Migration
As the leading 3G operator in Taiwan, CHT aggressively migrates 3G network to provide the best service to our customers.
Following network migration, CHT simultaneously promotes new devices, such as CHT9000, Diamond, iPhone…, etc.
2005 2006 2007 2008 2009 2010
WCDMA HSDPA HSUPA HSPA+
CHT9000CHT9100 iPhone
6/20
3G Traffic Growth
3G traffic and network load increase quickly� Most of increasing 3G traffic is PS data
� Traffic of high speed data increases ~ 30% per quarter
PS flat rate and smart phone induces heavy data traffic� Under keen market competition, all 3G operators in Taiwan
provide PS flat rate service
HSPA increases network capacity and traffic loading
7/20
Mobile Coverage Solutions
GSM/GPRS offers wide-area seamless coverage
3G/HSPA offers broadband coverage
EDGE compensates 3G broadband coverage hole
Repeater extends coverage range
Home/ public WiFi provides broadband access for indoor/hotspot
UrbanUrbanRuralRural SuburbanSuburbanUrbanUrban
GSM/GPRS
3G/HSPA3G/HSPA
repeater repeater
repeater
WiFi
WiFi
WiFiWiFi
EDGE EDGE
8/20
Carrier Allocation for CHT 3G Scenario Application Status
Single Carrier
F1(R99)
•Special enterprise area
•For voice and SMS only
area
~0.5 %
Single Carrier
F1(R99+HSDPA)
•Rural and low traffic area
•For coverage 28 %
Two Carriers
F1(R99)
F2(HSPA)
•Urban and sub-urban area
•For performance and
capacity
71 %
Two Carriers
F1(R99+HSPA)+
F2(HSPA)
•High traffic hot spot
•For capacity ~0.5%
Three Carriers
F1(R99)+
F2(HSPA)+
F3(R99+HSPA)
•Extra high traffic hot spot
•For capacity <0.1%
10/20
HW and SW Impact
More HSDPA carriers enabled, more hardware resources
demanded
� Enabling HSDPA must occupy a large block of CEs
� More amplifier power and RF device allocated for multi-carriers,
Must upgrade many new SW features
� Some functions are cost by traffic capacity
Following HSPA performance migration, investment to HW and SW upgrade will be increasing accordingly.
HW e
xpansion
SW li
cense
fee
capacity
Co
st
HW+SW migration
Time
Revenue
Net
wor
k co
st
Tra
ffic
vol
ume
&
11/20
HSDPA Power Allocation
HSDPA power can be set to be fixed or dynamic power allocation.
HSDPA power setting depends on coverage and traffic strategy.
� High power -> high throughput and coverage
� Priority to HSDPA traffic or to R99 DCH traffic.
Dedicated 2nd carrier can allocate more power to HSDPA.
-3 -6 -9 -12 -15Ec/No
Th
rou
gh
pu
t
Fixed power Dynamic power
12/20
Ec/No Impact
Enabling HSDPA will increase average Node B power and degrade Ec/No.
To achieve good performance, all RRM functions referred to Ec/No need to be optimized.
-15
-12
-9
-6
-3
0
4 8 12 16 20Ptx_total (W)Ptx_total (W)Ptx_total (W)Ptx_total (W)
Ec/N
o (
dB
)E
c/N
o (
dB
)E
c/N
o (
dB
)E
c/N
o (
dB
)
1-cell
2-cell_X
3-cell_X
EnableHSDPA No
-do
min
an
t cell a
rea
HSDPA
Throughput
Ec/No
13/20
Iub Transport
Double HSDPA speedcapability, only increase
20~40% average throughput.
HSDPA demand more transport bandwidth.
Traditional E1 is not the economic and efficient transport for HSDPA traffic.
HSDPA
traffic
Source: Harri Holma
~20%
~40%
14/20
CHT Mobile Backhaul Strategy
Initial solution: increase E1 to support HSDPA traffic
� Now mainly for low peak-rate site (< HSDPA 3.6M)
Today solution: E1+Ethernet hybrid backhaul
� E1 for CS traffic, signaling and synchronization
� 10/20/30M NG-SDH for PS
Next step: all-IP transport
� Need new version Node B or extra-interface module
� Need synchronization source
TDMTDM
NG SDHNG SDH
E1
Ethernet
E1
GE
STM-1
MRMR
TDMTDME1 E1
PTN PTN oror NG SDHNG SDHEthernetGE
15/20
Code Resource
Code resource will be insufficient for high rate HSDPA
� Common channels and R99 traffic, as well as HSDPA, need to occupy code resource.
� Code congestion rate will increase after enable high rate HSDPA
HSDPA for shared carrier is often down-rated by code congestion.
Dedicated carrier can provide more codes for HSDPA
Codes for HS-DSCHCodes for DCH,
HS-SCCH
16/20
Mobility Parameters
Mobility parameters planning become more complex after enabling HSDPA
� Ec/No is suddenly degraded by activating HSDPA
� R99 DCH is SHO, but HSDPA is HHO.
� HSDPA link-budget is different from R99
Traffic distribution between multi-carrier has to be adjusted by mobility parameters
� Direct HSDPA UE to HSDPA carrier
� Load balance for multi-carrier
Mobility parameters setting will be depended on carrier scenario, network function and traffic strategy
17/20
Network Mobility Optimization
1st carrier for idle mode, CS and R99 PS
� Setting cell reselection parameter to push all UE in idle mode to 1st carrier.
2nd carrier for HSDPA
� HSDPA UE make PS call is re-directed to 2nd carrier
2G
3G F2 (HSPA)
3G F1 (DCH)
idle voice data
: R99 UE
: R5/R6 UE
18/20
Performance and Capacity
Activating 2nd carrier for HSDPA traffic can improve the HSDPA throughput
� Dedicated carrier provide more power and codes
Voice call performance is improved after removing HSDPA loading in shared carrier
� Less Ec/No degraded by loading
Shared to Dedicated CarrierShared to Dedicated CarrierShared to Dedicated CarrierShared to Dedicated Carrier
19/20
Comparison for Shared and Dedicated Carrier
Shared Carrier Dedicated Carrier
Scheme
Advantage - Faster Deployment
- Cost Efficient
- Simpler parameter planning
-Minimum Impact to existing R99
performance
-Better HSDPA performance
Dis-
advantage
-Less capacity improvement
-Code tree limitation
-Impact exist Rel 99 performance
(Ec/No degradation)
-Additional HW & site re-
commissioning required
-More complex parameter
planning
Recommen
ded Area
Less capacity critical area
(rural area)
High capacity area
(Dense Urban, Hot Spot, Indoor,
20/20
Conclusions
Enabling HSPA will enhance QoE of customers, but increase CAPEX and OPEX.
Dedicated HSDPA carrier can get better network performance, mainly for HSDPA throughput and R99 QoS.
Market competition and quickly increasing PS traffic drive the demand for HSPA. The benefits for launching HSPA still depend on marketing and sales’ strategy.