IBS MIMO STUDY A LIVE SITE TESTING AND RESEARCH STUDY OF LTE MIMO
June 2016
A Comba Telecom White Paper
TABLE OF CONTENTS 1 BACKGROUND ........................................................................................ 3 ................................................................................................. 3
1.1
LTE ROLLOUT AROUND THE W ORLD
1.2
SISO AND MIMO IN IBS
1.3
PURPOSE
.............................................................................................. ................ 3
............................................................................................................ ................... 4
2 TESTING ENVIRONMENT ........................................................................... 4 2.1
B ASIC INTRODUCTION
2.2
SCENARIOS 2.2.1 SISO
................................................................. ................................................. 4
................................................................. ............................................................ 4
................................................................................................................................... 4
2.2.2 MIMO
.................................................................................................................................. 5 .................................................................................................................. ........ 5
2.2.3 ANT DENSITY 2.3
TESTING ITEMS & DEFINITION
......................................................................................................... 6
3 TESTING RESULT ..................................................................................... 6 ......................................... ...................................... 6
3.1
THROUGHPUT TESTING BETWEEN SISO AND MIMO
3.2
POWER UNBALANCES TESTING IN MIMO
3.3
THROUGHPUT PERFORMANCE TESTING AT DIFFERENT ANT DENSITY
......................................................................... ................... 7 ............................................................. 8
4 CONCLUSION AND COMBA SOLUTION .......................................................... 9 ........................................................................................................ ................... 9
4.1
CONCLUSION
4.2
COMBA SOLUTION
..................................................................................................................... 9
............................................................................................. ........................... 9
4.2.1 DIGIFLEX LITE+
........................................................................... ............................ 10
4.2.2 COMFLEX LOW POWER DAS
INDEX TO FIGURES AND TABLES FIGURE 1: LTE COMMERCIAL NETWORK .................................................................................................... 3 FIGURE 2: 70% OF WIRLESS TRAFFIC IS GENERATED INDOORS ......................................................................... 3 FIGURE 3: SISO MODE & MIMO MODE ................................................................................................... 3 FIGURE 5: MIMO SCENARIO ................................................................................................ ................... 5 FIGURE 6: ANT DENSITY SCENARIO ........................................................................................ ................... 5 FIGURE 7: DL THROUGHPUT TESTING RESULT.............................................................................................. 6 FIGURE 8: UL THROUGHPUT TESTING RESULT .............................................................................................. 6 FIGURE 10: UL POWER UNBALANCE TESTING RESULT .................................................................................... 7 FIGURE 11: DL THROUGHPUT IN DIFFERENT ANT DENSITY ................................... ......................................... 8 FIGURE 13: DIGIFLEX LITE+ PRODUCTS ...................................................................................................... 9 FIGURE 14: APPLICATION DIAGRAM ....................................................................................... ................. 10 FIGURE 15: COMFLEX LOW POWER PRODUCTS ......................................................................................... 10
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1 BACKGROUND 1.1 LTE ROLLOUTS AROUND THE WORLD Today, wireless data traffic is increasing rapidly and is mainly generated indoors. Consequently, this is driving rapid operator investment in LTE network deployment for in-building systems (IBS).
Figure 1: LTE commercial network launch globally
Figure 2: 70% of wireless traffic is generated indoors
1.2 SISO AND MIMO IN IBS There are two main models of IBS construction for LTE:
SISO (Single Input Single Output)
and MIMO (Multi Input Multi Output) . The differences are illustrated in the below diagrams:
MIMO Mode
SISO Mode
Figure 3: SISO mode & MIMO mode
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1.3 PURPOSE The purposes of this study are: 1.
To understand the throughput performance difference between SISO an d MIMO
2.
To understand the effect of power unbalance in MIMO
3.
To understand the throughput performance in different antenna density
2 TESTING ENVIRONMENT 2.1 BASIC INTRODUCTION The tests were conducted by China Telecom and Comba in Guangzhou, China: 1.
Comba Telecom oversaw the entire testing exercise.
2.
Use RRU for signal source and dongle as test terminal.
3.
JDSU testing software E6474A.
4.
Frequency bands: 2110-2125/1920-1935, total 15MHz
2.2 SCENARIOS
2.2.1 SISO
Figure 4: SISO scenario
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2.2.2 MIMO
Figure 5: MIMO scenario
2.2.3 ANT DENSITY Low Density
High Density
Figure 6: ANT density scenario
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2.3 TESTING ITEMS & DEFINITION Testing Items
Testing Location
Throughput testing between SISO and MIMO
Far-point
Mid-point
Near-point
Power unbalances testing in MIMO
Far-point
Mid-point
Near-point
Throughput performance testing in different ANT density
Far-point
Mid-point
Near-point
Table 1: Testing items
The locations are defined as below. Near-point: DL signal SINR=20~25dB (Typical 25dB), and RSRP=-85~-90dBm (Typical -85dBm) Mid-point: DL signal SINR=10~15dB (Typical 10dB), and RSRP=-95~-100dBm (Typical -100dBm) Far-point: DL signal SINR=0~5dB (Typical 0dB), and RSRP=-105~-110dBm (Typical -110dBm)
3 TESTING RESULTS 3.1 THROUGHPUT TESTING BETWEEN SISO AND MIMO 1.
DL throughput testing result
Figure 7: DL throughput testing result
2.
UL throughput testing result
Figure 8: UL throughput testing result
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For DL throughout, MIMO is about twice that of SISO in near-point, mid-point and far-point.
For UL throughout, MIMO is about twice that of SISO in near-point and mid-point, but similar in far-point
3.2 POWER UNBALANCES TESTING IN MIMO 1.
DL throughput testing result
Figure 9: DL Power unbalance testing result
The DL throughput is declining with the increasing of power unbalance
There are slight declines when unbalance is 3dB to 5dB, but a sharp decline at 8dB
2.
UL throughput testing result
Figure 10: UL Power unbalance testing result
The UL throughput is declining with the increasing of power unbalance
There are slight declines when unbalance is 3dB to 5dB, but decline sharply when at 8dB mid-point.
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3.3 THROUGHPUT PERFORMANCE TESTING AT DIFFERENT ANT DENSITY 1.
DL testing result
Figure 11: DL throughput in different ANT density
By increasing the ANT density, LTE coverage is enhanced, the average DL throughput is improved.
2.
UL testing result
Figure 12: UL throughput in different ANT density
By increasing the ANT density, LTE coverage is enhanced, the average UL throughput is improved.
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4 CONCLUSION AND COMBA SOLUTION 4.1 CONCLUSION From this study, we can arrive at below guidelines during LTE deployment: 1.
MIMO DL throughput performance is about double of SISO, while UL throughput improves in near-point and mid-point and fairly similar in far-point.
4.2
2.
Control the power unbalance of the 2 channels within 5 dB
3.
Higher ANT density = better throughput
COMBA SOLUTIONS
4.2.1 DIGIFLEX LITE+ DigiFlex Lite+ is Comba’s newly designed digital distributed antenna system, targeted for single operator scenarios. The solution is ideal for LTE MIMO and the single compact RU
not only supports LTE MIMO, but also 2G and 3G. The RU, embedded with a dual polarization antenna, can ensure zero power unbalance between 2 channels. Its flexible distributed structure and expansion capabilities can support up to 168 MRUs (Multi-service Remote Units) with single MAU (Multi-service Access Units) and 24 MEUs (Multi-service Extension Units) with combination of star and cascaded connection topologies.
The low cost MRU with power over fiber is ideally suited for high density deployment.
Figure 13: DigiFlex Lite+ products
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Figure 14: Application diagram
4.2.2 COMFLEX LOW POWER DAS The ComFlex Low power DAS is Comba’s modular d esigned flexible distributed antenna system, with full bandwidth to support multi-operator scenarios. The modular MU can
support mobile operators for new LTE bands upgrade extremely effectively, while the compact RU is designed to support LTE MIMO together with 2G and 3G and ensure zero power unbalance between 2 channels. The low power RU with 27dBm to 33dBm provides accurate coverage to maximize LTE performance.
Figure 15: ComFlex Low Power Products
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ABOUT COMBA TELECOM Comba Telecom is a leading suppli er of infrastructure and wirel ess enhancement solutions to mobile operators and enterprises to enhance and extend their wireless communications networks.
With over 50,000 system deployments around the world including turnkey
in-building systems, urban/rural wireless systems, and transport wireless networks, Comba Telecom’s end-to-end network solutions include consultation, network design, optimization and commissioning. Comba Telecom’s product portfolio includes DAS, small cells, tower mounted systems, antennas, subsystems, passive accessories, Wi-Fi systems and digital microwave links. Listed on the Hong Kong Stock Exchange, Comba Telecom is headquartered in Hong Kong and has operations throughout the Americas, Europe, Middle East, Africa and Asia Pacific. To learn more, visit www.comba-telecom.com and follow Comba Telecom on LinkedIn for regular updates.
www.comba-telecom.com
[email protected]
©2016 Comba Telecom.
© 2016 Comba Telecom. All rights reserved.
All Rights Reserved
Comba Telecom reserves the right to change, modify, transfer, or otherwise revise this publication and the
product specifications without notice. While Comba Telecom uses commercially reasonable efforts to ensure the accuracy of the specifications contained in this document, Comba Telecom and its affiliated companies will assume no responsibility for any errors or omissions.
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