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7/29/2019 huwcdmaawei

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Wireless Curriculum Development Section

ISSUE

WCDMA RNP Application of

TMA

1.0


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2Confidential Information of Huawei.No Spreading without Permission. Security Level: Internal

Review

The core of a TMA is a low noise amplifier used

for solving a limited uplink coverage problem

and increase the uplink coverage area.

This Slide first of all describes the antenna

feeder system, and then analyzes relevant

specifications and summarizes the advantages

and disadvantages of using a TMA in terms of

technical specifications, reliability and cost, etc.

At the end, it offers suggestions on when to use

a TMA.


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Objectives

Know the TMA structure and its

place in antenna feeder system.

Understand the advantages and

disadvantages of using a TMA in

terms of technical specifications,

reliability and cost

use a TMA.

Upon completion of this course,you will be able to:


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Course Contents

Antenna Feeder System

Functional Block Diagram of a TMA

Analysis of Specifications Related to NF Calculation

Calculation of NF at the Antenna Connector

Influences of a TMA

Suggestions


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Antenna, TMA, feeder cables,jumpers and lightning arresters.


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Course Contents





Influences of a TMA

Suggestions


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There are Tx and Rx channels in the TMA module.


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Course Contents





Influences of a TMA

Suggestions


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TMA NF Value:

According to design specifications, the TMAgain is 12+/-1dB and its typical value is 12dB


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NDDL Block Diagram:

1st

stage amplifier 2nd

stage amplifier 3rd

stage amplifier

6dB fixed

attenuator

0~12dB variable

attenuator

Switch

NDDL

One of the gain-adjustable LNA with typical gain 38dB,

32dB, 31dB, 30dB and 20dB, is used for WCDMA

network.


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Design rule without TMA

Design rule with TMA

LNA gain of NDDL shall be set to 38dB.

In order to guarantee that the receiver amplifier behind NDDL

can operate in the linear range, the gain from antenna outputto NDDL Rx output port has to be kept as 38dB.

Calculation:

TMA gain cable loss

jumper loss from the feeder cable connector to TMA

connector lightning arrester insertion loss jumper loss from the lightning

arrester connector to cabinet top connector jumper loss from the NDDL

connector to cabinet top connector + NDDL Gain

= 38dB


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Jumper Loss

The typical distance of jumper from antenna connector to TMA

connector is 1.5m, and 2.5m from TMA connector to feeder

cable connector, 1.5m from the lightning arrester connector to

cabinet-top connector.Based on the attenuation specification of 1/2 jumpers, we

assume that the total loss of 1/2 jumpers from the TMA

connector to cabinet-top connectors is 0.8dB, and the loss of

jumpers from the TMA connector to antenna connector is

0.3dB, when TMA is used.

The typical distance from the feeder cable connector to

antenna connector is 2.5m, when no TMA is used. So the loss

of jumper is 0.5dB.


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Cable loss from the NDDL connector to cabinet-topconnector, this specification is 0.4dB

The typical lightning arrester insertion loss is 0.2dB.

The loss rate of an Andrew 7/8 feeder cable is

6.11dB/100m. If the length of such a cable is L(m), its

loss is L*6.11/100dB. The loss rate of a 5/4 feeder

cable is 4.43dB/100m. If the length of such a cable is

L(m), its loss is L*4.43/100 dB.


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Course Contents





Influences of a TMA

Suggestions


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NF calculation, with TMA

NF at the cabinet-top connector with the NDDL gain being

38dB + cable loss + total jumper loss + lightning arrester

insertion loss.

Suppose that the sum of the total loss of cables and jumpersfrom the antenna connector to cabinet-top connectors and the

lightning arrester insertion loss is X.

When no TMA is used, NF = 2.2 + X,

Where in 2.2 is the NF at the cabinet-top connector when theNDDL gain is 38dB.

Except cable loss, total jumper loss + lightning arrester

insertion loss = 0.8 + 0.2 = 1.0 dB.


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Confidential Information of Huawei.No Spreading without Permission. Security Level: Internal


NF calculation without TMA

TMA gain - cable loss - jumper loss from the feeder cable

connector to TMA connector - lightning arrester insertion loss

- jumper loss from the lightning arrester connector to cabinet-top connector - jumper loss from the NDDL connector to

cabinet-top connector + NDDL Gain = 38dB

12dB - cable loss - 0.5dB - 02dB - 0.3dB - 0.4dB + NDDL Gain =

38dB

Cable loss = NDDL Gain - 27.4


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NF calculation with TMA


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NF calculation with TMA


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NF decreased with TMA


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Course Contents





Influences of a TMA

Suggestions


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Influences of a TMA

Calculation of receiver sensitivity

Receiver sensitivity (dBm)

= -174 (dBm/Hz) + NF _Ant connector (dB)

+ 10lg [1000 * Rb (kHz)]+ EbvsNo required (dB).

Using TMA, UL sensitivity of NodeB increases as NF

decreases. The increased value of sensitivity is equal to

the decreased NF.


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Influences of a TMA

Receiver sensitivity

If no external interference exists, the noise at the receiver when a

TMA is used is -174dBm/Hz + 10log (Rc) + NF with TMA, and that

when no TMA is used is -174dBm/Hz + 10log (Rc) + NF without

TMA. UL sensitivity of NodeB will increase as NF decreases, and

the increase of sensitivity is equal to the decrease in the NF.If external interference exists, the noise at the receiver when a

TMA is used is -174dBm/Hz + 10log (Rc) + Interference + NF with

TMA, and that when no TMA is used is -174dBm/Hz + 10log (Rc) +

Interference + NF without TMA. If the interference level is high,

the noise of receiver depends mainly on the interference level, inwhich case the decrease in the NF has a very small influence on

the noise to receiver.


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Influences of a TMA

Coverage

The max path loss (PL) on cell edge

PL (dB) = [ EiRP (dBm) (Sensitivity of Receiver (dBm) - Gain of

Antenna (dBi) + Body Loss (dB) + Interference Margin (dB) - SHO Gain

over fast fading (dB) + Fast Fading Margin (dB)) ]- Penetration Loss (dB)

- Slow Fading Margin (dB) + SHO Gain over Slow Fading (dB).

COST231-HATA model

PL (dB) = 46.3 + 33.9*log(f) - 13.82*log(Hb) - a(Hm)

+[44.9 - 6.55*log(Hb)]*log(d) + Cm

a(Hm) = [1.1*log(f) - 0.7]*Hm -[1.56*log(f) - 0.8]

Cm = 0 dB for medium sized city and suburban centers with moderate

tree density

Cm = 3 dB for metropolitan centers


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Influences of a TMA

Coverage

if f (frequency), Hm (height of mobile) and Cm are fixed

values and Hb (height of BS) is 30m,

PL (dB) = 35.22* log (d) + X

If Hb is 50m,

PL (dB) = 33.77* log (d) + XX represent other items in the formula.


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Influences of a TMA

Coverage calculation

NDDL amplification 28 29 30 31 32

Feeder cable loss (dB) 0.6 1.6 2.6 3.6 4.6

NF at the antenna connector (dB) 2.3 2.4 2.5 2.7 2.9

NF at the antenna connector

without TMA (dB)3.8 4.8 5.8 6.8 7.8

NF Decrease (dB) 1.5 2.4 3.3 4.1 4.9

Increase of sensitivity (dB) 1.5 2.4 3.3 4.1 4.9

Increase of cell radius,

Hb 30m (%)10.3 17.0 24.1 30.7 37.8

Increase of cell area,

Hb 30m (%)21.7 36.9 53.9 70.9 89.8

Increase of cell radius,

Hb 50m (%)10.8 17.8 25.2 32.3 39.7

Increase of cell area,

Hb 50m (%)22.7 38.7 56.8 74.9 95.1


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Influences of a TMA

Coverage example


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Influences of a TMA

Coverage analysis

TMA increases UL sensitivity, enhances the coverage area,

lowers the call-drop rate and improves the communication

quality.

TMA lowers the output power of MS required and reducesUL interference.

The cost of the mobile network construction can be also

reduced because of the increased effective coverage area

of a NodeB equipped with TMA.

In addition, because a TMA can improve the level and

quality of the UL signal, it can improve the communication

quality of both traffic channels and signaling channels.


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Influences of a TMA

Example ofcoverage improved - DXB Port Saeed Site using TMA


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Influences of a TMA

Example of coverage Improved - DXB Port Saeed Site using TMA

Comparison of UE Tx power with and without TMA, having 4.25 dB

average difference.


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Influences of a TMA

Site Name AL TALA

Structure Type Monopole

Antenna Height 30m

Antenna Type JB 5162100

Feeder Type 7/8" LCF-J50 RFS

Feeder Length 35m

Example of coverage improved - SHJ Al Tala site using TMA

No TMA TMA

Cable attenuation and other loss (dB) 4 4

NDDL Gain (dB) 38 30

NF (dB) 5.8 2.5

NF Improved (dB) 3.3


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Influences of a TMA

Example of coverage Improved - SHJ Al Tala site using TMA


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Influences of a TMA


Comparison of UE average Tx power with and without TMA, having

3.22 dB difference.


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Influences of a TMA



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Influences of a TMA


Comparison of DL average CPICH RSCP with and without TMA, having

0.14 dB difference.


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Influences of a TMA

UL capacity analysis

: load: adjacent cell interference factor

W / Rb: processing gain

N: user number

0

/( )

1 /

b

b

W RN

f E I

Capacity has no relation with the use of TMA in the

case of a cell with UL capacity-limited.


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Influences of a TMA

DL capacity analysis

N Ns

1(1 ) ( )c

s

pu virtual

NA f

ii PLPfWN

WN

110

0

/)(1

C: power ratio of CCH, pu: DL originating load

Avirtual: load of virtual services/user

: non-orthogonal factor, : adjacent cell interference factor

PL1i : DL average coupling loss of the cell, P1i : DL output power.


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Influences of a TMA


TMA may increase DL coupling loss and

decrease DL capacity.

Assumed conditions:

DL insertion loss of the TMA: 0.7dB

(Tx filter loss 0.4dB + jumper loss 0.3dB)

non-orthogonal factor: 0.4

adjacent cell interference factor: 0.65

NoW: thermal noise power.


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Influences of a TMA

DL capacity calculation

Conditions: 1. DL capacity-limited 2. unchanged cell radius

DL originating load 0.75 0.75 0.75 0.75 0.75

Coupling loss with TMA (dB) 125 130 135 140 145

Coupling loss with TMA (dB) 125.7 130.7 135.7

140.7 145.7

DL non-orthogonal factor 0.4 0.4 0.4 0.4 0.4

Adjacent interference 0.65 0.65 0.65 0.65 0.65

DL capacity when a TMA is

used/not used1.0 0.99 0.99 0.98 0.96


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Influences of a TMA


DL capacity decreases by 0.3 ~ 9.7% when the average

DL coupling loss increases from 130dB to 150dB.


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Influences of a TMA


If the UL capacity is limited before a TMA is used,

the cell radius, both UL/DL coverage radiuses,

increases due to the decrease in the NodeB NF after a

TMA is used.We can approximately assume that the increase

in the DL coupling loss is equal to the increase in the

UL coupling loss plus TMA insertion loss which is

0.7dB.Suppose that the DL capacity remains not

limited, and the DL non-orthogonal factor remains

unchanged at 0.4.


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Influences of a TMA

DL capacity calculation

NDDL amplification 28 29 30 31 32

Feeder cable loss (dB) 0.6 1.6 2.6 3.6 4.6

NF at the antenna connector (dB) 2.3 2.4 2.5 2.7 2.9

NF at the antenna connector

without TMA (dB)3.8 4.8 5.8 6.8 7.8

NF decrease (dB) 1.5 2.4 3.3 4.1 4.9

Increase in DL coupling loss 2.2 3.1 4.0 4.8 5.6


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Influences of a TMA

Impact ofDL capacity by cable losses and types


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Influences of a TMA

Other factors

TMA allows for a longer distance between antenna

and cabinet, and makes site selection easier.

Despite its higher cost, TMA may expand the

coverage area, reduce the number of sites required and

equipment room cost.

Using TMA can reduce the system reliability because

it is connected in series with the NodeB. The failure rate of

a series connection is equal to the sum of failure rates of

its components, and the downtime of a series connection

is equal to the sum of downtimes of its components.


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Course Contents





Influences of a TMA

Suggestions


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Suggestions

TMA is recommended to be used under

the conditions below.

A large coverage area, e.g. rural, suburban or

highway, because UL coverage is limited for the

most of time but DL coverage is usually not limited.

An area, e.g. dense urban or urban,

according to RNP, DL capacity is not limited. ULsensitivity and coverage area can be increased by

using TMA.


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Suggestions

Receiver noise using TMA:-174dBm/Hz + 10log(Rc) + Interference + N (with

TMA)

-174dBm/Hz + 10log(Rc) + Interference + NF

(without TMA)

When the decrease in the noise after TMA is used,

=(-174dBm/Hz + 10log(Rc) + Interference + NF without

TMA)- [-174dBm/Hz + 10log(Rc) + Interference + NFwith TMA] > X dB.

Analysis method is the same as that without TMA.

and TMA is recommended to be used.


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Suggestions

About selection of feeder cables

7/8 cable is used in below 50m length.

5/4 cable is used in above 50m length.

The reason is the maximum cable loss that

the NDDL can support is 6dB including cable,

jumper and insertion losses.


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