Download - WO NP2003 E01 1 UMTS Capacity Estimation
UMTS Capacity Estimation
ZTE University
Content
UMTS Service mode Common Capacity Design Methods Uplink Capacity Estimation Downlink Capacity Estimation Estimation Examples
CS Domain Service Model
Key parameter: call frequency, call duration, blocking probability
Average Erlang = call frequency ×duration / 3600
Call DurationCall Duration Call DurationCall Duration
Call SetupCall Setup Call ReleaseCall Release Call SetupCall Setup Call ReleaseCall Release
PS Domain Service Model
Session (WWW)Session (WWW) Session (WWW)Session (WWW)
CallCall CallCall Call (Web Page)Call (Web Page)
ClickClick ClickClick ClickClick
ActiveActive ActiveActive ActiveActiveDormantDormant DormantDormant
PacketPacket PacketPacket PacketPacket
ActiveActive
PS Domain Service Model
Dormant status and Active status conversion Every session can contain several packet calls, different
data services and different user types have different features
Resource occupied by packet call varies alone with the burst transmission
PS Service Model - Example
service Bearer rate(kbps)
Mean packet size(byte)
Mean packets in a call
Mean calls/session
Reading time between calls(second)
Email 64 480 32 2 5
www 144 480 25 5 5
Download 64 480 62 2 5
MMS 64 480 32 2 5
Streaming 384 480 267 1 0
Parameter Name Parameter definition Unit
DL Bit rate Downlink service bit rate kbps
DL Mean Packet Size Mean downlink packet size
Byte
DL Mean # Packets Mean downlink packet quantity
DL Mean Calls/session Mean calls of downlink session
DL Reading time between calls
Transmission duration between downlink calls
second
DL Mean packets in a call Mean packets in one downlink session
DL BLER Downlink service quality requirement
DL PS Activity Factor Downlink activating factor
PS Domain Service Model
UL Bit rate Uplink service bit rate kbps
UL Mean Packet Size Mean uplink packet size Byte
UL Mean # Packets Mean uplink packet quantity
UL Mean Calls/session Mean calls of uplink session
UL Reading time between calls
Transmission duration between uplink calls
second
UL Mean packets in a call Mean packets in one uplink session
UL BLER Uplink service quality requirement
UL PS Activity Factor Uplink activating factor
BHSA Busy hour sessions attempt
PS Domain Service Model
Service Category
Service type Basic characteristic Example
Conversation The time relationship between information entities in the stream must be kept, session mode (small delay, strict delay jitter requirement)
Voice, video phone
Streaming The time relationship between information entities in the stream must be kept
Multimedia data stream
Interactive Request/response mode, data integrity must be kept
Web browser, internet game
Background Data integrity must be kept, high delay tolerance
Email download in background
User Group Classification
Classification principle Based on user consumption capability and consumption behavior
Note: User groups are distinguished by service type, service rate, service quality and service intensity.
User type Group features
High - end High income group, enterprises and managers. Providing high rate access service.
Medium -end
General enterprises and some high income consumers. Providing information inquiry, mobile entertainment and mobile financial services.
Lower - end Middle income class and students. Providing data services such as SMS and some mobile game services
Service Penetration
Percentage of user distribution in different application environments are different
Percentage of high-end, middle-end and lower-end users in different application environments are different
Service model statistic characteristic relates to percentages mentioned above
A B C D
Total 10% 30% 30% 30%
High End 30% 10% 5% 0%
Medium End 40% 50% 40% 10%
Low End 30% 40% 55% 90%
Traffic Analysis for Single Subscriber
CS Domain
Service type
Mean busy hour calls
Mean call duration
Activate factor
Mean speed
(kbps)
Mean busy hour erl per user
Tel. 1.25 72 0.5 12.2 0.025
Video phone
0 (lower end)
0.05 (medium end)
0.1 (high end)
54 1 64 0 (lower end)
0.00075 (middle end)
0.0015 (high end)
Mean busy hour Erl. Per user=mean busy hour calls*mean call duration/3600
Traffic Analysis for Single Subscriber
PS Domain
Service type Penetration rate
BHSA Mean packet
size (byte)
Mean packets in a call
Mean calls/session
Busy hour throughput
per user ( kbit)
Web service
Low-end user
50% 0.01 480 25 5 4.8
Medium end user
75% 0.02 480 25 5 9.6
High-end user
100% 0.03 480 25 5 14.4
Node: penetration rate means the percentage of UEs which support this service in total UEs.
Busy hour throughput per user = BHSA* mean calls in a session *mean packets in a call*mean packet size*8/1000
Equivalent Erl = Busy hour throughput per user / (Bearer rate *3600)
Traffic Analysis for Single Subscriber
The average traffic according to the Service Model in each
transmission environment is :
Average traffic for each subscriber = ∑ Ratio of subscriber
group* Service penetration * average traffic of this group
Content
UMTS Service mode Common Capacity Design Methods Uplink Capacity Estimation Downlink Capacity Estimation Estimation Examples
UMTS Network Dimensioning Procedure
Capacity Estimation Procedure
Hybrid service intensity analysis The UMTS system provides multiple services and the
hybrid service intensity analysis makes the system capacity consumed by various services equivalent to that consumed
by a single service. Uplink capacity estimation
Estimate the NodeB number that meets the service demand based on the hybrid service intensity analysis.
Downlink capacity estimation It is a verification process. The NodeB transmission power
formula is used to calculate the channel number that can be provided by the current NodeB scale so as to verify whether this channel number can meet the capacity requirement, and if it cannot, stations need be added.
Common Capacity Design Methods
Equivalent Erlangs method
Post Erlang-B method
Campbell method
Equivalent Erlangs Method
Principle: Make a service equivalent to another service and calculate the total Erl.
Example Service A: 1 channel for each connection and the total is 12 erl. Service B: 3 channels for each connection and the total is 6 erl. If 1 erl service B = 3 erl service A, altogether 30 erl service A
shall be equivalent and 39 channels shall be required (under 2% blocking rate).
If 3 erl service A = 1 erl service B, altogether 10 erl service B shall be equivalent and 17 service B channels shall be required (equal 17*3=51 service A channels under 2% blocking rate).
++
Low speed service
equivalent
High speed service equivalent
2 Erl low speed
service
1 Erl high speed service
Capacities meeting the same GoS are different
The calculation result The calculation result is related to the is related to the
equivalent mode equivalent mode
Equivalent Erlangs Method
Post Erlang-B Method
Principle: Calculate the capacity required by each service respectively and add them.
Example Service A: 1 channel for each connection and the total is 12 erl. Service B: 3 channels for each connection and the total is 6 erl. Service A requires 19 channels (under 2% blocking rate). Service B requires 12 service B channels (equal 12*3=36
service A channels, under 2% blocking rate).
These two services require 19+36=55 channels
Post Erlang-B Method
Suppose services A and B are the same kind, where, Service A: 1 channel for each connection and the total is 12 erl.
Service B: 1 channel for each connection and the total is 6 erl.
Based on the Post Erlang-B method Service A requires 19 channels (under 2% blocking rate).
Service B requires 12 channels (under 2% blocking rate).
Altogether 19+12=31 channels are required.
Based on traditional Erlang-B method
The total traffic of services A and B is 12+6=18 erl and altogether
26 channels are required under 2% blocking rate.
Required channel number estimated through the Post Erlang-B
method is too large.
1 Erl service A
1 Erl service B
++
1 Erl service A and 1 Erl service B
Capacities meeting the same GoS are different
The calculation The calculation
result is too result is too
pessimistic pessimistic
Post Erlang-B Method
Campbell Method
c
aCCapacity ii
cfficOfferedTra
iii
iii
aerl
aerl
c
2
ic
Principle: Make multiple services equivalent to a virtual service and calculate the capacity on the basis of the virtual service.
iserviceofcapacityCiiserviceofamplitudea
niancevnmeanafactorcapacityc
i...
...*var
*.
3036112 ii aerl
6636112 222ii aerl
Campbell Method
Example Service A: 1 channel for each connection and the total is 12
erl. Service B: 3 channels for each connection and the total is 6
erl
Mean & variance
2.23066
c
63.132.2
30 Traffic Offered cα
Campbell Method
Capacity factor c
Virtual traffic
21 channels (virtual channels) are required to meet the virtual traffic under 2% blocking rate.
Under 2% blocking rate, channel number required by each
service is shown as follows:
Service A:
Service B:
Different channel numbers are required to meet the GOS
requirements of diversified services.
Compared with the former two methods, the calculation result
through the Campbell method is more reasonable.
471)2.221(1 C
493)2.221(2 C
Campbell Method
If the reference service is the voice service :
Campbell Method
voicevoicevoice
serviceserviceserviceservice vNoEbR
vNoEbRAmplitude
*/*
*/*
Content
UMTS Service mode Common Capacity Design Methods Uplink Capacity Estimation Downlink Capacity Estimation Estimation Examples
jtotal
j
jjj PI
P
Rv
WNoEb
)/(
W: indicates the chip rate.
vj: indicates user j’s activation factor.
Rj: indicates user j’s data rate.
Pj : indicates user j’s signal receive power
Itotal: indicates total broadband receive power with
the thermal noise power included in the NodeB.
Uplink Load Analysis
Eb/No the receive signal in the NodeB must reach Eb/No required by the service demodulation.
The receive power at the NodeB receive end should meet
the following formula so that the user signal can meet the
demodulation requirement:totaljtotal
jjj
j ILI
vRNoEb
WP
)(1
1
jjj
total
jj
vRNoEb
WI
PL
)(1
1
Define a connection load
factor Lj:
N
jtotalj
N
jj ILP
11
The total receive power of all N users from
one cell is:
Uplink Load Analysis
Uplink Load Analysis
The total receive power at the NodeB receive end consists
of three parts:Notherintatal PPPI
indicates the total interference power of in-cell users.
indicates the total interference power of out-cell users.
indicates the NodeB thermal noise power.
Neighbor cell’s interference factor i
i= Other cell interference /Local cell
interference
inP
otherP
NP
The total user receive power of the NodeB:
Define the noise lifting as the ratio of total broadband
receive power to the noise power of the NodeB:
N
jtataljotherin ILiPP
1
)1(
N
jj
otherintatal
tatal
N
total
LiPPI
I
P
INR
1
)1(1
1
Uplink Load Analysis
Define the uplink load factor
to be:
The noise lifting can be represented
to be:
N
j
jjj
N
jjUL
vRNoEb
WiLi
11)/(
1
1)1()1(
UL
NR
1
1
)1(10)( 10 ULLOGdBNR
Uplink Load Analysis
The uplink capacity is limited by interference increase:
25 30 35 40 45 50 55 60 65
2
3
4
5
6
7
8
9
10
11
user number
nois
e r
ise(d
B)
Shanghai dialectShanghai dialect Minnan Minnan
dialectdialect mandarinmandarin
CantoneseCantonese
Uplink Load Analysis
Uplink Capacity Estimation
In the case of a single service, evaluate the channel quantity provided by every cell according to the load formula and further evaluate the total number of base stations satisfying the uplink capacity requirement.
To budget composite traffic, based on the Campbell algorithm, make different services consumption on the system resource equivalent to the single service consumption on the system resource, and then evaluate the quantity of channels to be provided by every cell according to load formula, and further evaluate the number of base stations satisfying the composite traffic requirement.
R99/HSUPA mixed calculation
During the uplink capacity calculation ,decide how much uplink load will be designed in R99 and HSUPA
By simulation, calculate how much PS throughput can be carried by HSUPA
Calculate how much of the remaining PS service to be carried by R99
Calculate equivalent intensity of services
Calculate the variance, average value and capacity factor of the composite service
System virtual traffic A
Calculate the quantity of equivalent voice channels
in the cell
Quantity of virtual channels in the cell
Virtual service capacity B of the cell
Number of cells
A/B
R99 Uplink Capacity Algorithm
Content
UMTS Service mode Common Capacity Design Methods Uplink Capacity Estimation Downlink Capacity Estimation Estimation Examples
Downlink Load Analysis
To correctly demodulate useful signals, the UE must
overcome interference from the following three
aspects
Nothertatal PPPI )1(
P represents total power of signals from current cell
represents total interference power of signals from the outside of the cell
represents thermal noise power from the UE
represents orthogonal factor of the downlink
otherP
NP
Downlink Load Analysis
By referring to the derivation means of uplink load
factor, denote the downlink load factors as follows:
N
j j
jjDL i
RW
NoEbv
1
])1[(/
)/(
W represents chip rate at 3.84M chip/s
vj represents activation factor of the user j
jR represents bit rate of the user j
represents the average orthogonal factor in a cell
i represents the average ratio of the NodeB power from other cell to that from this cell
Downlink Load Analysis
Total downlink power allocation
DL
N
jj
j
b
jMS
TXBS
RW
NE
LWN
P
1
1
0
_
Where, represents the noise power spectrum density on the front of the receiver in the mobile station
represents the average path loss of the cellL
) (suppose KTNFNFKTNMS 290174 =+-+
MSN
46 48 50 52 54 56 58 60 62 64
32
34
36
38
40
42
44
46
user number
Tx P
ow
er
(dB
m)
Public channelPublic channel
Two usersTwo users
One userOne user
Three usersThree users
..
..
..
Downlink Downlink powerpower
The downlink capacity is limited by transmission
power of the base station
Downlink Load Analysis
Downlink Load and Scale Analysis
Estimate downlink capacity after analyzing the channel quantity required by uplink capacity, and observe whether the downlink can support the mobile station to work in the designated coverage area and its channel quantity reaches the channel quantity generated by the uplink
Calculate the quantity of equivalent voice channels to be provided by every cell
Calculate the quantity of equivalent voice channels availably provided by every cell
Compare the above two results
Content
UMTS Service mode Common Capacity Design Methods Uplink Capacity Estimation Downlink Capacity Estimation Estimation Examples
Assumed Conditions
Channel environment: downtown area TU 3 km/h System design load: 50% Voice service blocking rate: 2% Interference factor from the adjacent cell: 0.65 Area of the city zone: 40.8 square kilometers
Voice CS64 PS64/64 PS64/128 PS64/384
Data rate(k) 12.2 64 64 64 64
Activity factor 0.67 1 1 1 1
Eb/No 4.2 2.87 1.6 1.6 1.6
Forecast traffic 3000 400 100 5 2
Voice CS64 PS64/64 PS64/128 PS64/384
Data rate(k) 12.2 64 64 128 384
Activity factor 0.58 1 1 1 1
Eb/No 7.7 7.7 7.4 6.4 8
Forecast traffic 3000 400 100 35 20
Uplink:
Downlink:
Assumed Conditions
Input: system load requirement and coverage requirement
Uplink coverage estimation
Downlink coverage estimation
Uplink capacity estimation
Quantity of base stations satisfying uplink coverage
Quantity of base stations satisfying coverage
requirement
Quantity of base stations satisfying downlink coverage
Quantity B of channels provided by the cell
Compare the results and evaluate the larger one
End
Quantity A of channels required by the cell
A<BAdd base stations
Based on traffic model
Based on power
Yes
No
Estimation Flow Chart
Emission end
Maximal emission power (dbm)
Antenna gain (dbi)
Human body loss (db)
Effective emission power
Receiving end
Thermal noise power spectrum density (dbm/HZ)
Thermal noise power (dbm)
Receiver noise coefficient (db)
Receiver noise (dbm)
Interference margin (db)
Bit rate (kbit)
Processing gain (db)
Receiving Eb/No (db)
Receiver sensibility
Antenna gain (dbi)
Line loss
Other
Power control margin
Soft handoff gain
Shade fading margin
Penetration loss
Maximal path loss
Uplink Coverage Estimation1. Uplink budget
2. Calculate the cell coverage radius based on a specific propagation model:
Path loss k1 k2log(d) k3Hms k4log(Hms) k5log(Heff) + k6log(Heff)log(d) k7(diffraction loss) clutter loss
30Heff-6.55k6
-13.82k544.6k2
152.4k1
0.540.540.540.50.65Radius( Km )
PS64/384PS64/128PS64CS64Voice
Uplink coverage is limited by the CS64 kps service
Uplink Coverage Estimation
3. Calculate the quantity of base stations required by uplink Coverage area of the three-sector base station
22 488.05.05.095.138
9KmRS
The quantity of base stations is 40.8/0.488=84
Uplink Coverage Estimation
af amplitudefor 1 amplitudefor ratebit
servicefor servicefor ratebit amplitude Relative
0
0
NE
NE
b
b
Voice: 1
CS64: 64 x 1 x 100.287/12.2 x 0.67 x = 5.76
PS64/64: 64 x 1 x 100.16/12.2 x 0.67 x = 4.3
PS64/128: 64 x 1 x 100.16/12.2 x 0.67 x = 4.3
PS64/384: 64 x 1 x 100.16/12.2 x 0.67 x = 4.3
Equivalent intensity of each service
Variance, mean and capacity factor of the
composite service
Virtual traffic A of the system
Quantity of equivalent
voice channels in the cell
Quantity of virtual
channels in the cell
Number of cells
A/B Virtual traffic A of
the cell
Equivalent intensity of each service
Uplink Capacity Estimation
42.010
42.010
42.010
42.010
i
iiaerlmean 1.57663.423.453.410067.540013000
i
iiaerliance 7.182713.423.453.410067.540013000var 2222
Mean
Virtual traffic of the system mean/capacity factor 5766.1/3.17 1818.96(Erl)
Equivalent intensity of each service
Variance, mean and capacity factor of the
composite service
Virtual traffic A of the system
Quantity of equivalent
voice channels in the cell
Quantity of virtual channels
in the cell
Number of cells
A/B
Virtual traffic A of the cell
Capacity factor variance/mean 3.17
Variance
Uplink Capacity Estimation
Quantity of equivalent voice channels availably provided by the cell
N
j
o
bj
N
EvR
Wf
1*
1*1
1*)1(
%50 65.0f
Get the quantity of equivalent voice channels N 54
Where, and
Equivalent intensity of each service
Variance, mean and capacity factor of the
composite service
Virtual traffic A of the system
Quantity of equivalent
voice channels in the cell
Quantity of virtual channels
in the cell
Number of cells
A/B
Virtual traffic A of
the cell
Uplink Capacity Estimation
Equivalent intensity of each service
Variance, mean and capacity factor of the
composite service
Virtual traffic A of the system
Quantity of equivalent
voice channels in the cell
Quantity of virtual channels
in the cell
Number of cells
A/B Virtual traffic A of the cell
Quantity of virtual channels in every cell
c
aCCapacity ii )(
Quantity of virtual channels in the cell (54 1)/3.17 16
Virtual traffic of every cell
Look up the Erl B table, and provide 9.83Erl for 16 virtual channels in the case of 2% of call loss ratio
Uplink Capacity Estimation
Equivalent intensity of each service
Variance, mean and capacity factor of the
composite service
Virtual traffic A of the system
Quantity of equivalent
voice channels in the cell
Quantity of virtual channels
in the cell
Number of cells
A/B Virtual traffic A of the cell
Uplink Capacity Estimation
Number of cells=Virtual traffic of the system/virtual traffic of every =1818.96/9.83=186
Number of three-sector base stations=186/3=62
Downlink Capacity Estimation
Integrate uplink and downlink coverage budget and uplink capacity budget to determine that there are 84 base stations currently and authenticate whether downlink power meets the requirement.
Quantity A of channels to be provided by the cell
Average traffic of every cell
Virtual traffic of every cell
Quantity of virtual channels in every cell
Determine the number of stations
Quantity B
of channels availably provided by the ce;;
End A<BYes NO
Add base
stations
Voice: 3000/84/3 11.9 Erl
CS64: 400/84/3 1.59 Erl
PS64/64: 100/84/3 0.4 Erl
PS64/128: 35/84/3 0.14 Erl
PS64/384: 20/84/3 0.079 Erl
Average traffic of various services in every cell
Determine the number of stations
Quantity A of channels to be
provided by the cell
Average traffic of every cell
Virtual traffic of every cell
Quantity of virtual channels
in every cell
Quantity B
of channels availably provided by the cell
End
A<B
Yes
Downlink Capacity Estimation
Virtual traffic of every cell Equivalent service intensity of each service on
the downlink Voice: 1, CS64: 7.8, PS64/64: 7.3 PS64/128: 13.1, PS64/384: 50 Mean of composite traffic
Variance of composite traffic
355.19=50 0.079+13.1 0.14+7.3 0.4+7.8 1.59+ 11.9var 2222 iance
Traffic factor capacity factor variance/mean 355.19/33.04 10.75
Virtual service capacity of the cell mean/capacity factor 33.04/10.75 3.07 (Erl)
33.04=50 0.079+13.1 0.14+7.3 0.4+7.8 1.59+ 11.9 mean
Determine the number of stations
Quantity A of channels to be
provided by the cell
Average traffic of every cell
Virtual traffic of every cell
Quantity of virtual channels
in every cell
Quantity B
of channels availably provided by the cell
End
A<B
Yes
Downlink Capacity Estimation
c
aCCapacity ii )(
Quantity of equivalent voice channels: 7 10.75 1 76
Quantity of virtual channels in every cell Look up the Erl B table and obtain that
the quantity of virtual channels required by 3.07 Erl virtual traffic is 7
Quantity of equivalent voice channels to be provided by every cell
Quantity A of channels to be
provided by the cell
Average traffic of every cell
Virtual traffic of every cell
Quantity of virtual channels
in every cell
Determine the number of stations
Quantity B
of channels availably provided by the cell
End
A<B
Yes
Downlink Capacity Estimation
Calculate the quantity of channels availably provided by every cell based on power
])1[(/
)/(*1
/
)/(***
1
1
jj
N
j j
jj
N
j j
jjN
RW
NoEbv
RW
NoEbvLP
P
P represents the maximum service transmission power, which is 13 W
represents the noise power spectrum density on the front of the mobile station receiver, and its value is -169 dBm
L represents the average path loss, which is evaluated by subtracting 6 dBm from the maximum path loss
j represents orthogoal factor, which is 0.6 for the multipath channel
represents interference factor from an adjacent cell. It is 0.65 for the three-sector antenna macro cell
j
Obtain that the quantity of equivalent voice channels actually provided by every cell is 71
NP
Quantity A of channels to be
provided by the cell
Average traffic of every cell
Virtual traffic of every cell
Quantity of virtual channels
in every cell
Determine the number of stations
Quantity B
of chann
els availa
bly provided by the cell
End
A<B
Yes
Downlink Capacity Estimation
Comparison The quantity of channels to be provided by
every cell is 76 The quantity of channels actually provided
by every cell is 71 There are 84 base stations currently, and it
cannot satisfy downlink capacity requirement, and some stations should be added.
Quantity A of channels to be
provided by the cell
Average traffic of every cell
Virtual traffic of every cell
Quantity of virtual channels
in every cell
Determine the number of stations
Quantity B
of channels availably provided by the cell
End
A<B
Yes
Downlink Capacity Estimation
Iterative calculation
726588
717287
717286
717685707684
697683
Number of channels provided
Number of channels required
Number of base stations
If there are 88 base stations, the uplink and downlink coverage capacity requirement can be met
In the case, the base station coverage radius is
488.095.1/88/8.40 Km
Downlink Capacity Estimation