maximizing the performance of lte in indoor · pdf filehigh capacity lte and lte-a network...

Copyright © Rosenberger 2016 – Proprietary / Confidential

Maximizing the Performance of LTE

in Indoor Environment

Director, Marketing & Infrastructure Solutions Rosenberger Asia Pacific Electronic Co., Ltd.

Denis Ng

http://www.bharatexhibitions.com/en/LTE2016/index.php

Copyright © Rosenberger 2016 – Proprietary / Confidential www.rosenberger.com | 2

Outline

Understanding the Technical Requirements for a high Speed,

High Capacity LTE and LTE-A network

In-building Coverage Solution for LTE-Advanced

• Passive vs Active DAS

• High, Medium or Low Power Active DAS?

• Inter-System Interference and PIM Considerations

• In-building Coverage Strategies and Solution

Summary and Takeaways


Technical Requirements for LTE and LTE-A Capacity


The LTE OFDM Air Interface

How much capacity is available?

f = 15 kHz

One RB = 12 x 7 RE = 84 RE

12 sub-carriers (180kHz)

frequency Resource Element &

Resource Block

QPSK

2 bits/sym

16QAM

4 bits/sym

64QAM

6 bits/sym

Modulation Type

Frequency

Scalable Bandwidth

Sub-carriers

Cyclic Prefix

Symbols

Time

FFT

To download @ 5 Mbps

- 64QAM 4/5: 7 RB

- 16QAM 4/5: 10 RB

- 16QAM 1/2: 17 RB

- QPSK 1/2: 35 RB

20 MHz = 100 RB


Basic Requirements

for a High Speed LTE Network

Small Cells

7

6

5

4

3

2

1

0-5 0 5 10 15 20

QPSK 1/3

QPSK 2/3

QPSK 1/2

16QAM 1/2

16QAM 2/3

16QAM 4/5

64QAM 1/2

64QAM 2/3

64QAM 4/5

Shannon

Sp

ectr

al

eff

icie

ncy [

bit

s/s

/Hz]

SINR [dB]

QPSK Modulation

2 bits/sym

16 QAM Modulation

4 bits/sym

64 QAM Modulation

6 bits/sym

High Order

Modulation

(HOM)

Intercell Interference

Radio channel

0

1

2

3

4

5

6

7

8

9

Spectr

al E

ffic

iency

b/s

/Hz

G-Factor [dB]

SISO

SIMO

SFC

JC

-10 -5 0 5 10 15 20 25 30 35 40

20MHz LTE

Up to 75Mbps (SISO)

Up to 150Mbps (2x2MIMO)

SISO / Diversity

MIMO

MIMO

~75 Mbps

@ 20MHz BW


Different Dimensions of Improvements

in LTE-Advanced

Source : Ericsson


In-building Coverage Solution for LTE-Advanced


Passive, Active, or Hybrid DAS?

BTS

MU

RU


Passive DAS for LTE-A?

Pros of Passive DAS

An all-passive coaxial cable system is highly linear

Capable of handling multiple downlink carriers with no measurable IM

products

• IM3 of passive components typically in the range of -120 to -150 dBc

High system reliability and Cheap

9

Cons of Passive DAS

Feeder cable size is typically limited to 7/8” or 1-1/4”

Not suitable for buildings that require long feeder runs

• Inherent insertion loss limits the size of installation to typically a 35

floor high rise building, or around 50,000 sq m

At high frequencies, the system loss becomes very high

• Lower DL coverage, poorer uplink sensitivity and reduced SNIR

Expensive to implement MIMO for LTE.


DAS

DAS Loss eNode B

UE1

d

30 dB

DL 46 dBm

QPSK

Sh MU

RU

ATT

High, Medium or Low Power

Active DAS?

NFm

NFl

NFl < NFm < NFh

DAS

DAS Loss 17 dB

DL 33 dBm UE2

d

16QAM Sm

RU

UE3

d

64QAM DL 16 dBm

Sl

iRU

NEU

NFh

http://www.blackberry.com/ap/products/handhelds/blackberry7130/blackberry7130v.shtml




Uplink Performance

Inter-System Interference Considerations

Frequency TXf RXf

Po

we

r

Tx Power

Interferer Interfered

Guard Band

Rx Sensitivity

Rx Noise Floor

Tx Sideband Level

894 869

Tx Sideband Noise

Duplexer Tx Response

f_offset Spurious /

Out-of-

Band

Emissions

Transmitter Receiver

UMTS Rx Filter

Response

TXf RXf

Out-of-Band Carrier

Insufficient Filter

Rejection

Blocking Considerations


Intermodulation occurs when two or

more carriers mix on non-linear device

and create undesired output at other

frequencies.

In a communications system, this means

that signals in the downlink may cause

interference with adjacent uplink channels.

fIM3 = 2 * f1 - f2

＝2×1805 - 1880

＝1730 MHz = f4

fIMm+n = mf1 ± nf2

IMD3 is always the

worst case !!!

fIM5 = 3 * f1 - 2*f3

＝3×1805 - 2*1880

＝1730 MHz = f4

Uplink Performance

Passive Intermodulation (PIM)

1705 1780 1805 1842.5 1880

f (MHz)

IM3

1730 f 1 f 2

Rx band Tx band

1800MHz

f 4

dBc

dBm

f 3

IM5

i

v

V (t)i

V (t)1 V (t)2

Load

i (t)o

Non-lineardevice


In-building Coverage Strategies

1. Focus on TCO

• Think long term, not short term; Multi-operator not single operator

• Network should be easily scalable, support future technologies, and

provide a flexible upgrade path

2. Ensure good quality connections, not just good coverage

• In the past there has been a trade-off between coverage and capacity

• Now, users expect both

• Move from voice to data capacity – SNIR, MIMO, CA

• Low noise figures are crucial to ensure maximum data throughput

3. Ability to move capacity rather than always provision for the peak

• Mobile traffic is bursty and sporadic

• Historically operators have always had to provision for peak traffic

• Intelligent in-building coverage should allow the dynamic allocation of

capacity to where and when it is needed

• Capacity no longer needs to be hard-wired

• Reduction in capex and opex costs as a result


Multi-operator, Multi-sector, Multi-band Active and Hybrid DAS

Supports SISO or MIMO

Dynamic Capacity

Routing

. . . . .

iM2U

Switching Matrix

1

2

8

BTS Card

. . . . .

Smart POI

1

2

8

“Smart” DAS MIMO Solution

• Intelligent Multi-sector Master Unit (iM2U)

• Network Expansion Unit (NEU)

• Intelligent Remote Unit (iRU) - RADiANT

• High Power Remote Unit (HPRU)

Multi-operator, Multi-Band

Base Station Banks

BTS Band 1

BTS Band 2

BTS Band 8

BTS Band 8

EXT Combiner

Hybrid MIMO DAS 3+1

HPRU

AC MIMO-2

MIMO-1

iRU

iRU

iRU

Hybrid DC Fiber (up to 300m)

. . . .

1

8

iRU

NEU

Active MIMO DAS 3+1

AC MIMO-2

MIMO-1

iRU

. . . .

1

16

NEU

AC

. . . .

1

16

NEU

iRU

iRU

AC

Active MIMO DAS 3+3 or 4+4

iRU

MIMO-2

MIMO-1

iRU

iRU

iRU

iRU

. . . .

1

8

NEU

AC

Hybrid MIMO DAS 3+1

MIMO-2

MIMO-1







“Smart” DAS

Dynamic Capacity Routing

Dynamic capacity routing allows the size of sectors to be changed to

accommodate temporary surge in traffic within the DAS network.


“Smart” DAS Components

Smart POI Unit

Smart POI – BTS Card Smart POI – IM2U

NEU

Low Power RU (RADiAnt) Hybrid Fiber/DC Cable High Power RU

Modular

PA Unit



LTE is designed as a wireless high speed data network.

• Requires Small Cell size AND Interference Management

• Maximize SINIR through careful antenna placements to operate at 64QAM

and improve MIMO performance

LTE-A capacity options

• MIMO and Sectorization

• Carrier Aggregation

How well can Passive DAS support LTE-A?

How to enhance upload speeds?

• Again, time to rethink on Passive DAS

• Ensure sufficient isolation between co-located systems

• PIM specs – No such thing as cheap and good!

Rosenberger is a Total Solutions Provider for muli-operator, IBS

equipment and have successfully deployed active and passive IBS

solutions in 15 countries throughout Asia Pacific, Middle East, & South

America


There is nothing that is a more certain sign of insanity than to do the same thing over and over again and

expecting different results.

A Final Quote …

Albert Einstein


Denis Ng Director, Marketing & Infrastructure

Solutions

E: [email protected]

T: +65 6696 6039

F: +65 6696 6039

No. 3 Anxiang Street, Block B,

Tianzhu Airport Industrial Zone

Beijing 101300, China

THANK YOU www.rosenbergerap.com

maximizing the performance of lte in indoor · pdf filehigh capacity lte and lte-a network...

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