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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
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
Copyright © Rosenberger 2016 – Proprietary / Confidential
Technical Requirements for LTE and LTE-A Capacity
Copyright © Rosenberger 2016 – Proprietary / Confidential www.rosenberger.com | 4
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
Copyright © Rosenberger 2016 – Proprietary / Confidential www.rosenberger.com | 5
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
Copyright © Rosenberger 2016 – Proprietary / Confidential www.rosenberger.com | 6
Different Dimensions of Improvements
in LTE-Advanced
Source : Ericsson
Copyright © Rosenberger 2016 – Proprietary / Confidential
In-building Coverage Solution for LTE-Advanced
Copyright © Rosenberger 2016 – Proprietary / Confidential www.rosenberger.com | 8
Passive, Active, or Hybrid DAS?
BTS
MU
RU
Copyright © Rosenberger 2016 – Proprietary / Confidential www.rosenberger.com | 9
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.
Copyright © Rosenberger 2016 – Proprietary / Confidential www.rosenberger.com | 10
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
Copyright © Rosenberger 2016 – Proprietary / Confidential www.rosenberger.com | 11
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
Copyright © Rosenberger 2016 – Proprietary / Confidential www.rosenberger.com | 12
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
Copyright © Rosenberger 2016 – Proprietary / Confidential www.rosenberger.com | 13
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
Copyright © Rosenberger 2016 – Proprietary / Confidential www.rosenberger.com | 14
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
Copyright © Rosenberger 2016 – Proprietary / Confidential www.rosenberger.com | 15
“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.
Copyright © Rosenberger 2016 – Proprietary / Confidential www.rosenberger.com | 16
“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
Copyright © Rosenberger 2016 – Proprietary / Confidential
Summary and Takeaways
Copyright © Rosenberger 2016 – Proprietary / Confidential www.rosenberger.com | 18
Summary and Takeaways
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
Copyright © Rosenberger 2016 – Proprietary / Confidential www.rosenberger.com | 19
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
Copyright © Rosenberger 2016 – Proprietary / Confidential
Denis Ng Director, Marketing & Infrastructure
Solutions
E: denis@rosenbergerap.com
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
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