Channel Element Dimension Ing Guideline_v1

1 Channel Element resource model

1.1 Number of users per site If the number of users (simultaneously connected) per site is known the following expression can be applied to calculate the number of channel elements needed:

{nCE ,UL=∑i

N i ΓUL , i ¿¿¿¿

where

Ni is the number of currently connected users per site for service i.

i is the channel element factor for service i.

1.2 Channel element cost modelTable 1 gives an example of channel element factors, showing the channel element consumption for different services on different radio bearers. Please note that this is an example and the cost-model may differ depending on Node B and CE licensing.

Table 1. Example of channel element factors

Service CE factor

UL DL

AMR12.2 1 1

PS64 4 2

PS128 8 4

PS384 16 8

2 Examples

2.1 R99, only conversational traffic admitted in busy hour

2.1.1 Purpose

The purpose of this example is to show calculations for a mix of conversational and R99 best effort traffic. This example assumes that only conversational traffic

is admitted in busy hour. This means a throughput degradation for best effort traffic.

For simplicity there is only one type of conversational traffic (speech). This example assumes maximum impact of Enhanced Soft Congestion, which means that only 64 kbps radio bearers will be used for best effort traffic. Re-transmissions are included in the best effort traffic. The grade of Service (GoS) for conversational and best effort traffic is assumed to be 2%.

For simplicity complete partitioning is used, which gives an overestimation of the required resources.

2.1.2 Traffic input

Table 2. Example 1: traffic input

Service RAB RB

Offered traffic per site, A

Activity factor KAF

SHO factor κUL DL

Speech Speech 6 Erlang 6 Erlang - 0.3

R99 best effort PS data

PS interactive64, 128,

38450MB 500 MB 0.7 0.3

2.1.3 Identifying the number of simultaneous users

Step 1: Converting best effort traffic to Erlang

A64/64,UL = ((5010000008)/3600)/(640000.7) = 2.5 Erlang

A64/64,DL = ((50010000008)/3600)/(640000.7) = 24.8 Erlang

Step 2: Max traffic

A64/64 = max(24.8, 2.5) = 24.8 Erlang

Step 3: Soft handover factor

ASHO,Speech = 61,3 = 7.8 Erlang

ASHO,64/64 = 24.81,3 = 32.2 Erlang

Step 4: Estimating the maximum number of simultaneous users from offered traffic

MSpeech = ErlangB(7.8, 0.02) = 14

2.1.4 Calculating number of CEs

Step 1a: Calculating nCE,Peak per service

nCE,Speech,UL = 141 = 14 CE

nCE,Speech,DL = 141 = 14 CE

Step 1b: Calculating total nCE,Peak for busy hour

nCE,Peak,UL = 14 + 0 = 14 CE

nCE,Peak,DL = 14 + 0 = 14 CE

Step 2: Calculating nCE,AVE

nCE,AVE,UL = 7.81(10.02) = 7.6 CE

nCE,AVE,DL = 7.81(10.02) = 7.6 CE

Step 3: Calculating nCE,BE

nCE,BE,UL = 32.24 = 128.8 CE

nCE,BE,DL = 32.22 = 64.4 CE

Step 4: Finding the total number of CEs required

nCE,TOT,UL = max(14, (7.6+128.8)) = 136.4 CE

nCE,TOT,DL = max(14, (7.6+64.4)) = 72 CE

2.2 R99, conversational and best effort traffic admitted in busy hour

2.2.1 Purpose

The purpose of this example is to show calculations for a mix of conversational and R99 best effort traffic on the site. This example assumes that conversational as well as best effort traffic is admitted in busy hour. This gives no degradation of the peak throughput for best effort traffic in busy hour, since no impact of Enhanced Soft Congestion is assumed.

For simplicity there is only one type of conversational traffic (speech). Re-transmission is included in the best effort traffic. Grade of Service (GoS) for conversational and best effort traffic is assumed to be 2%.

For simplicity complete partitioning is used, which gives an overestimation of the required resources.

2.2.2 Traffic input


Service RAB RBTraffic distri-bution


Activity factor KAF

SHO factor κUL DL

Speech Speech 6 Erlang 6 Erlang n/a 0.3


PS interactive

64/64 70% 50MB 500 MB 0.7 0.3


PS interactive

64/128 20% 50MB 500 MB 0.7 0.3


PS interactive

64/384 10% 50MB 500 MB 0.7 0.3

2.2.3 Identifying number of simultaneous users

Step 1: Converting best effort traffic to Erlang + best effort traffic distribution

A64/64,UL = ((0.705010000008)/3600)/(640000.7) = 1.7 Erlang

A64/128,UL = ((0.205010000008)/3600)/(640000.7) = 0.5 Erlang

A64/384,UL = ((0.105010000008)/3600)/(640000.7) = 0.25 Erlang

A64/64,DL = ((0.7050010000008)/3600)/(640000.7) = 17.4 Erlang

A64/128,DL = ((0.2050010000008)/3600)/(1280000.7) = 2.5 Erlang

A64/384,DL = ((0.1050010000008)/3600)/(3840000.7) = 0.4 Erlang

Step 2: Max traffic

A64/64 = max(17.4, 1.7) = 17.4 Erlang

A64/128 = max(2.5, 0.5) = 2.5 Erlang

A64/384 = max(0.4, 0.25) = 0.4 Erlang


ASHO,Speech = 61,3 = 7.8 Erlang

ASHO,64/64 = 17.41,3 = 22.6 Erlang

ASHO,64/128 = 2.51,3 = 3.2 Erlang

ASHO,64/384 = 0.41,3 = 0.5 Erlang



M64/64 = ErlangB(22.6, 0.02) = 31

M64/128 = ErlangB(3.2, 0.02) = 8

M64/384 = ErlangB(0.5, 0.02) = 3





nCE,64/64,UL = 314 = 124 CE

nCE,64/64,DL = 312 = 62 CE

nCE,64/128,UL = 84 = 32 CE

nCE,64/128,DL = 84 = 32 CE

nCE,64/384,UL = 34 = 12 CE

nCE,64/384,DL = 38 = 24 CE


nCE,Peak,UL = 14+124+32+12 = 182 CE

nCE,Peak,DL = 14+62+32+24 = 132 CE


nCE,AVE,UL = 7.81(10.02) = 7.6 CE

nCE,AVE,DL = 7.81(10.02) = 7.6 CE


nCE,64/64,UL = 22.64 = 90.4 CE

nCE,64/64,DL = 22.62 = 45.2 CE

nCE,64/128,UL = 3.24 = 12.8 CE

nCE,64/128,DL = 3.24 = 12.8 CE

nCE,64/384,UL = 0.54 = 2.0 CE

nCE,64/384,DL = 0.58 = 4.0 CE


nCE,TOT,UL = max(182, (7,6+90.4+12.8+2.0)) = 182 CE

nCE,TOT,DL = max(132, (7,6+45.2+12.8+4.0)) = 132 CE

2.3 R99 + HSPA, only conversational traffic admitted in busy hour

2.3.1 Purpose

The purpose of this example is to show CE calculations for HSPA. For simplicity it is assumed that there is no R99 best effort traffic on the site. UL E-DCH traffic has not been specified. This example assumes that only conversational traffic is admitted in busy hour. This gives a throughput degradation for best effort traffic in busy hour. The example assumes no impact of Enhanced Soft Congestion.

2.3.2 Traffic input


Service RAB RBTraffic distri-bution


Activity factor KAF

SHO factor κUL DL

Speech Speech 6 Erlang 6 Erlang n/a 0.3


PS interactive

64/HS 60% 50MB 500 MB 0.7 0.3


PS interactive

384/HS 15% 50MB 500 MB 0.7 0.3


PS interactive

EUL/HS 25% 50MB 500 MB 0.7 0.3

HS target rate 500 kbps

EUL target rate 128 kbps (8CE)

Reservation of CE for EUL SHO 128 kbps (8CE)

2.3.3 Identifying the number of simultaneous users

Step 1: Converting best effort traffic to Erlang

ADL,HS = ((50010000008)/3600)/(5000000.7) = 3.2 Erlang

Step 2: UL A-DCH & EUL traffic distribution

A64HS,UL = 0.750.83.2 = 1.9 Erlang

A384HS,UL = 0.750.23.2 = 0.5 Erlang

AEUL = 0.253.2 = 0.8 Erlang


ASHO,Speech = 61.3 = 7.8 Erlang

A64HS,UL = 1.31.9 = 2.5 Erlang

A384HS,UL = 1.30.5 = 0.65 Erlang

AEUL,Serving = 10.8 = 0.8 Erlang

AEUL,nonServing = 0,30.8 = 0.24 Erlang



M64HS,UL = ErlangB(2.5, 0.02) = 7

M384HS,UL = ErlangB(0.65, 0.02) = 4

MEUL,Serving = ErlangB(0.8, 0.02) = 4

MEUL,nonServing = ErlangB(0.24, 0.02) = 3






nCE,Peak,UL = 14+0 = 14 CE

nCE,Peak,DL = 14+0 = 14 CE


nCE,AVE,UL = 7.81(10.02) = 7.6 CE

nCE,AVE,DL = 7.81(10.02) = 7.6 CE


nCE,64HS,UL = 2.54 = 10

nCE,384,UL = 0,6516 = 10.4

nCE,EUL,Serving = 0,88 = 6.4

nCE,EUL,nonServing = 0,258 = 2


nCE,TOT,UL = max(14, (7,6+10+10.4+6.4+2)) = 36.4 CE

nCE,TOT,DL = max(14, (7,6+0)) = 14 CE

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Channel Element Dimension Ing Guideline_v1