( 12 ) United States Patent
`Stapleton et al .
`
`US 10,750,382 B2
`( 10 ) Patent No .:
`( 45 ) Date of Patent :
`* Aug . 18 , 2020
`
`US010750382B2
`
`( 71 )
`
`( 72 )
`
`( * ) Notice :
`
`( 54 ) OPTIMIZATION OF TRAFFIC LOAD IN A
`DISTRIBUTED ANTENNA SYSTEM
`Applicant : DALI WIRELESS , INC . , Menlo Park ,
`CA ( US )
`Inventors : Shawn Patrick Stapleton , Burnaby
`( CA ) ; Seyed Amin Hejazi , Burnaby
`( CA )
`( 73 ) Assignee : DALI WIRELESS , INC . , Menlo Park ,
`CA ( US )
`Subject to any disclaimer , the term of this
`patent is extended or adjusted under 35
`U.S.C. 154 ( b ) by 0 days .
`This patent is subject to a terminal dis
`claimer .
`( 21 ) Appl . No .: 16 / 661,368
`( 22 ) Filed :
`Oct. 23 , 2019
`( 65 )
`Prior Publication Data
`May 14 , 2020
`US 2020/0154288 A1
`Related U.S. Application Data
`( 63 ) Continuation of application No. 13 / 950,160 , filed on
`Jul . 24 , 2013 , now Pat . No. 10,506,454 .
`( 60 ) Provisional application No. 61 / 678,016 , filed on Jul .
`31 , 2012 .
`( 51 ) Int . Cl .
`H04W 24/02
`H04W 16/04
`H04W 88/08
`( 52 ) U.S. Cl .
`CPC
`
`( 58 ) Field of Classification Search
`H04W 88/085 ; H04B 10/2575 ; H04B
`CPC
`10/25753 ; H04L 41/5025
`See application file for complete search history .
`
`( 56 )
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`8/2004 Stratford
`6,785,558 B1 *
`7/2013 Trigui
`8,498,207 B2 *
`4/2019 Lee
`10,264,626 B2 *
`10,506,454 B2 * 12/2019 Stapleton
`2002/0119772 A1 *
`8/2002 Yoshida
`
`2008/0139205 A1 *
`
`6/2008 Sayeedi
`
`2010/0278530 A1 * 11/2010 Kummetz
`
`2012/0039320 A1 *
`
`2/2012 Lemson
`
`HOLW 88/085
`455/561
`H04L 41/5025
`370/235
`HO4W 4/70
`H04W 16/04
`H04W 24/00
`455/423
`HO4W 36/0038
`455/436
`H04B 10/2575
`398/41
`HO3F 1/3247
`370/338
`
`( Continued )
`Primary Examiner Matthew C Sams
`( 74 ) Attorney , Agent , or Firm Jason H. Vick ; Sheridan
`Ross , PC
`( 57 )
`ABSTRACT
`A system for dynamically routing signals in a Distributed
`Antenna System includes a plurality of Digital Access Units
`( DAUS ) . The plurality of DAUs are coupled and operable to
`route signals between the plurality of DAUs . The system
`also includes a plurality of Digital Remote Units ( DRUS )
`coupled to the plurality of DAUs and operable to transport
`signals between DRUs and DAUs and a plurality of Base
`Transceiver Stations ( BTS ) . The system further includes a
`plurality of traffic monitoring modules and a network opti
`mization goal and optimization algorithm .
`19 Claims , 11 Drawing Sheets
`
`( 2009.01 )
`( 2009.01 )
`( 2009.01 )
`H04W 24/02 ( 2013.01 ) ; H04W 16/04
`( 2013.01 ) ; H04W 88/085 ( 2013.01 )
`
`Collect Information in DAS
`Network
`
`Analyze Traffic Information
`( KPIs ) And Traffic
`performance ( QoS ) in DAS
`Network
`
`Optimize Traffic Performance
`( QoS ) in DAS Network
`
`910
`
`912
`
`914
`
`916
`
`NO
`
`Does The Reconfigured
`DAS Network Estimate an
`Acceptable Level of
`Performance ?
`
`YES
`
`Reconfigure DAS Network
`
`918
`
`

`

`US 10,750,382 B2
`Page 2
`
`( 56 )
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`2013/0071112 A1 *
`
`2013/0114963 A1 *
`
`3/2013 Melester
`5/2013 Stapleton
`
`2013/0128810 A1 *
`
`5/2013 Lee
`
`HO4B 17/0085
`398/38
`HO4W 24/02
`398/115
`H04W 84/042
`370/328
`
`* cited by examiner
`
`

`

`U.S. Patent
`
`Aug. 18 , 2020
`
`Sheet 1 of 11
`
`US 10,750,382 B2
`
`Cell 12
`
`Cell 4
`
`DRU5 / DRU 6
`
`DRU
`
`DRU 4
`
`1
`
`DRU 3 ORU 2
`106 105 104
`
`Cell 10
`
`Optical
`Cable
`103
`
`BTS
`Sector
`
`101
`
`2
`
`Sector
`3
`110
`
`Cable
`
`RF
`Cable
`
`RF
`Cable
`
`DAU 1
`102
`
`DAU2
`108
`
`DAU 3
`
`Cell 6
`
`Cell 7
`
`Cell 8
`
`Cell 5
`
`DRU
`
`DRU
`12
`
`DRU
`
`DRU
`
`Cell 2
`DRU DRU 9
`10
`
`DRU
`19
`
`DRU
`20
`
`DRU
`
`DRU
`21
`
`DRU DRU
`
`Cell 9
`
`Optical
`Cable
`
`Optical
`Cable
`
`Network
`Optimization
`120
`
`Traffic Monitor Unit
`121
`
`FIG . 1
`
`

`

`U.S. Patent
`
`Aug. 18 , 2020
`
`Sheet 2 of 11
`
`US 10,750,382 B2
`
`15
`
`DRU
`
`DRU
`41
`
`DRU
`39
`
`DREU
`
`DRU
`42
`
`DRU
`36
`Cel 4
`DRU
`DRU
`
`DRU
`
`DRU
`11 R8
`R
`
`R
`
`DRU 5 DRUG
`
`DRU 4
`
`DRUA
`
`DRUT
`
`13 DRU
`DREU
`
`DRO
`
`Cell 6
`
`Cell 7
`
`21
`
`DRU
`26
`
`DRU
`
`DRA DRU
`DRU
`25
`22 213
`DRU
`DRU
`23
`212 211 210
`
`DRU
`
`Cell 12
`
`Cell 11
`
`Cel 1
`DRU 2
`DRU 3
`205 204
`
`DRU
`33
`
`DRU
`
`DRU
`18
`
`DRE
`DRU
`31 30
`
`DRU
`
`DRU
`29
`Cell 10
`DRU
`
`DRU
`35
`
`DRU
`
`DR
`2
`
`DRU
`
`DRU
`15
`ce3
`DRU
`DRU
`
`19
`
`BTS
`
`Sector 1
`201
`
`Sector 2
`
`Sector 3
`
`203
`
`DAU 1
`202
`
`DAU2
`208
`
`DAU3
`
`209
`
`220
`
`Network
`Optimization
`
`Traffic Monitor Unit
`221
`
`FIG . 2
`
`

`

`U.S. Patent
`
`Aug. 18 , 2020
`
`Sheet 3 of 11
`
`US 10,750,382 B2
`
`DRU2
`
`DRU 8
`Cell 2
`
`Der
`
`DRU 10
`
`DRU 19 DRU 20
`
`DRU 5
`
`DRU 6
`
`DRU 4
`
`DRU 1
`307
`
`ORUZ
`
`DRU 2
`DRU 3
`306 305 304
`
`BTS N
`
`Sector 1
`309
`
`RF Cable
`
`Sector 2
`
`RF Cable
`
`Sector 3 hot
`
`RF Cable
`
`:
`
`BTS 1
`
`Sector 1
`301
`
`RF Cable
`
`Sector 2
`
`RF Cable
`
`Sector 3 het
`
`RF Cable
`
`DRU 18
`
`DRU 15 DRU 21
`Cel 3
`
`DRU 17 DRU 16
`
`Optical
`Cable
`303
`DAU 1
`302
`
`DAU 2
`308
`
`DAU 3
`
`Opical
`Cable
`
`Optical
`Cable
`
`Network
`Optimization
`320
`
`Traffic Monitor
`Unit
`321
`
`FIG . 3
`
`

`

`U.S. Patent
`
`Aug. 18 , 2020
`
`Sheet 4 of 11
`
`US 10,750,382 B2
`
`Optical Network
`
`403
`
`
`
`LAN Port 1
`
`
`
`LAN Port 2
`
`
`
`PEER Port M
`
`
`
`Local Router L 415
`
`
`
`Traffic Monitor at ports
`
`406
`
`Port 10 Ext Port 1D Ext
`
`
`
`
`
`Ext
`
`Port 2D Ext Port 20
`
`
`Ext Port ND Ext
`Port NU
`
`Ethernet
`
`408
`
`402
`
`
`
`Host Unit / Server
`
`FIG . 4
`
`407
`
`Remote Operational Control
`
`
`
`Physical Node
`
`Link Uplink
`
`Down
`
`410
`
`400
`
`
`
`Physical Node
`
`
`
`Physical Node
`
`
`
`
`
`404 Down Link lakink .
`
`Down Link Up Link
`405
`
`RF Network
`
`

`

`U.S. Patent
`
`Aug. 18 , 2020
`
`Sheet 5 of 11
`
`US 10,750,382 B2
`
`RF Network
`
`504
`
`503
`
`Down Link Up Link Dawn
`Link Tuinwink .
`
`
`
`Down Link Hulp Link
`
`
`
`501
`
`
`
`Physical Node
`
`
`
`Physical Node
`
`
`
`Physical Node
`
`506
`
`:
`
`
`
`
`
`Digital Remote Unit
`
`
`
`
`
`Ext Port 1D Ext Port 10
`
`Port 20 Ext Port 2D Ext
`
`
`
`
`
`Ext Port ND
`
`Ext Port NU
`Remote Router R 515
`
`
`
`
`
`Traffic Monitor at ports 516
`
`
`
`LAN Port 2
`
`
`
`- LAN Port 1
`
`
`
`PEER Port M
`
`Optical Network
`
`Computer
`
`505
`
`
`
`Ethernet Switch
`
`Ethernet
`
`508
`
`FIG . 5
`
`
`
`Wireless Access Points
`
`

`

`U.S. Patent
`
`Aug. 18 , 2020
`
`Sheet 6 of 11
`
`US 10,750,382 B2
`
`Cell 4
`
`13
`DRO
`14
`
`DRU 8
`
`DRU
`
`DRUG
`
`DRU 54 DRU6
`
`DRU 4
`
`DRU 1
`
`ORUZ
`
`Cell 12
`
`Cell 11
`
`DRU 3DRU 2
`606 605604
`
`DRU
`19
`
`DRU
`20
`
`DRU
`
`DRU
`
`DRU
`21
`Cell 3
`DRU
`DRU
`
`DRU
`
`Cell 10
`
`Cell 8
`
`BTS Hotel
`610
`Picocel 11
`Picocel 12
`Picocell IN
`
`Picocell 21
`Picocell 22
`Picocell 2P
`
`Picocell 31
`Picocell 32 -
`Picocell 30
`
`RF
`Cable
`
`DAU 1
`
`Optical
`Cable
`603
`
`Cell 9
`
`RF
`Cable
`
`DAU 2
`
`Optical
`Cable
`
`Cable
`
`DAU 3
`
`Optical
`Cable
`
`Network
`Optimization
`620
`
`Traffic
`Monitor Unit
`621
`
`FIG . 6
`
`

`

`U.S. Patent
`
`Aug. 18 , 2020
`
`Sheet 7 of 11
`
`US 10,750,382 B2
`
`Cell 5
`
`DRO
`
`12
`
`DRU
`
`10
`
`DRU
`19
`
`DRU 9
`
`DRU
`20
`
`DRU
`
`DRU
`
`DRU 21
`DRU DRU DRU
`
`Cell 6
`
`Cell 7
`
`Cell 8
`
`DRUS DRU 6
`
`DRU 4
`
`DRU 1
`
`DRUT
`
`Cell 12
`
`Cell 11
`
`BTS Hotel
`710
`
`Picocell 12
`Picocell IN
`
`Picocel 21
`Picocel 22
`Picocell 2P
`Picocell 31
`Picocell 32
`Picocell 30
`
`Traffic Monitor Unit
`720
`
`DRU 3 DRU 2
`706 705 704
`
`Optical
`Cable
`703
`RF
`Cabie | DAU 1
`702
`
`RF
`Cable
`
`DAU 2
`
`Cable DAU 3
`
`Network
`Optimization
`721
`
`Cell 9
`
`Optical
`Cable
`
`Optical
`Cable
`
`FIG . 7
`
`

`

`U.S. Patent
`
`Aug. 18 , 2020
`
`Sheet 8 of 11
`
`US 10,750,382 B2
`
`Cell 5
`
`DRU
`DRU
`13
`12
`DRU
`DRU 8
`Cell 2
`ORU
`
`DRU
`
`DRU
`20
`
`DRU
`
`DRU
`ceis
`DRU
`17
`
`DRU
`
`21
`
`DRU
`
`Cell 7
`
`Cell 8
`
`Cell 12
`
`Cell 11
`
`DRU 5 V DRU 6
`
`DRU 4
`
`DRU 1
`Cell 1
`DRU ZADRU 2
`806 805804
`
`BTS Hotel
`810
`Picocell 11
`Picocel 12
`Picocell IN
`
`Picocell 21
`Picocell 22
`:
`Picocell 2P
`Picocell 37
`Picocell 32
`Picocell 3Q
`
`Traffic Monitor Unit
`820
`
`Digital
`Interfaces
`( 830 )
`
`Optical Cable
`803
`
`Cell 9
`
`DAU 1
`802
`
`DAU 2
`808
`
`DAU 3
`
`821
`
`Network
`Optimization
`
`Optical Cable
`
`Optical Cable
`
`FIG . 8
`
`

`

`U.S. Patent
`
`Aug. 18 , 2020
`
`Sheet 9 of 11
`
`US 10,750,382 B2
`
`Collect Information in DAS
`Network
`
`Analyze Traffic Information
`( KPIs ) And Traffic
`performance ( QoS ) in DAS
`Network
`
`Optimize Traffic Performance
`( QoS ) in DAS Network
`
`912
`
`914
`
`916
`
`Does The Reconfigured
`DAS Network Estimate an
`Acceptable Level of
`Performance ?
`
`YES
`
`Reconfigure DAS Network
`
`918
`
`FIG . 9
`
`

`

`U.S. Patent
`
`Aug. 18 , 2020
`
`Sheet 10 of 11
`
`US 10,750,382 B2
`
`START
`
`Number of Users per DRU
`DRUs distance from each other
`- How are the DRUs assigned to
`different Sectors and BTS
`
`Calculate different KPIs at the DRUS :
`KPI , 1E { BC , HO , CI }
`BC : Blocked Call
`HO : Handover
`CI : Compactness Index
`
`Calculate QoS :
`QoS = w ; .KP180 + W .KPIn0 + 1z.KPIC
`
`TERMINATE
`
`FIG . 10
`
`

`

`U.S. Patent
`
`Aug. 18 , 2020
`
`Sheet 11 of 11
`
`US 10,750,382 B2
`
`START
`
`i
`
`Generate
`the initial
`Population
`
`1110
`
`1112
`
`Analyze Traffic
`Information ( KPIs )
`And Traffic
`performance
`( QoS ) for all
`sectorizations
`( individual )
`
`1
`2
`
`SORT
`
`X
`X2
`
`X
`
`QoS
`Qos ,
`2082
`
`Generate New
`individuals with conditional
`Prob . Vector
`
`1124
`
`Convergence
`Criterion Satisfied
`
`YES
`
`TERMINATE
`
`1116
`
`1118
`
`1122
`
`1120
`
`[ = P ( x1 , x2 , L , XH DRUS 7-1 )
`
`Best
`Individual
`
`Update Generation Counter
`
`wy
`
`1
`2
`
`x
`X
`
`X
`
`Oos
`QoS ,
`
`Qos
`
`A , is Set of Individuals ( population )
`
`Individual X , = ( X1 , X2 9. , Xip Drus ) , x ; € { Sm \ sector " n " from BTS " m m " }
`FIG . 11
`
`

`

`1
`OPTIMIZATION OF TRAFFIC LOAD IN A
`DISTRIBUTED ANTENNA SYSTEM
`
`US 10,750,382 B2
`
`10
`
`15
`
`CROSS - REFERENCES TO RELATED
`APPLICATIONS
`This application is a continuation of pending U.S. patent
`application Ser . No. 13 / 950,160 filed Jul . 24 , 2013 , now U.S.
`Pat . No. 10,506,454 , entitled “ OPTIMIZATION OF TRAF
`FIC LOAD IN A DISTRIBUTED ANTENNA SYSTEM ” ,
`which application claims priority to U.S. Provisional Patent
`Application No. 61 / 678,016 , filed on Jul . 31 , 2012 , entitled
`“ OPTIMIZATION OF TRAFFIC LOAD IN A DISTRIB
`UTED ANTENNA SYSTEM ” . The aforementioned appli
`cations are incorporated herein by reference , in their
`entirety , for any purpose .
`SUMMARY OF THE INVENTION
`
`2
`The system further includes a plurality of traffic monitoring
`modules and a network optimization goal and optimization
`algorithm .
`In an embodiment , a system for dynamically routing
`5 signals in a Distributed Antenna System is provided and
`includes a plurality of Digital Access Units ( DAU ) . The
`plurality of DAUs are coupled and operable to route signals
`between the plurality of DAUs . The system also includes a
`plurality of Digital Remote Units ( DRUS ) coupled to the
`plurality of DAUs and operable to transport signals between
`DRUs and DAUs and one or more Base Transceiver Stations
`( BTSs ) . The system further includes a traffic monitoring
`unit .
`Numerous benefits are achieved by way of the present
`invention over conventional techniques . For example ,
`embodiments of the present invention provide for traffic
`monitoring in a DAS network , improving network perfor
`mance and user experience . These and other embodiments of
`20 the invention along with many of its advantages and features
`The present invention generally relates to wireless com
`are described in more detail in conjunction with the text
`munication systems employing Distributed Antenna Sys
`below and attached figures .
`tems ( DAS ) as part of a distributed wireless network . More
`specifically , the present invention relates to a DAS utilizing
`BRIEF DESCRIPTION OF THE DRAWINGS
`traffic monitoring and optimization . Wireless network opera- 25
`tors faces the continuing challenge of building networks that
`FIG . 1 is a block diagram according to one embodiment
`effectively manage high data - traffic growth rates . Mobility
`of the invention showing the basic structure and an example
`of the transport routing , traffic monitoring and network
`and an increased level of multimedia content for end users
`typically employs end - to - end network adaptations that sup
`optimization based on having a single 3 sector BTS with 3
`port new services and the increased demand for broadband 30 DAUs and 7 DRUs daisy chained together for each cell .
`and flat - rate Internet access . One of the most difficult
`FIG . 2 is a block diagram according to one embodiment
`challenges faced by network operators is caused by the
`of the invention showing the basic structure for a frequency
`physical movement of subscribers from one location to
`reuse pattern of N = 1 and an example of the transport
`another , and particularly when wireless subscribers congre
`routing , traffic monitoring and network optimization based
`gate in large numbers at one location . A notable example is 35 on having a single 3 sector BTS with 3 DAUs and 7 DRUS
`a business enterprise facility during lunchtime , when a large
`daisy chained together for each cell .
`number of wireless subscribers visit a lunch room or caf
`FIG . 3 is a block diagram according to one embodiment
`eteria location in the building . At that time , a large number
`of the invention showing the basic structure and an example
`of subscribers have moved away from their offices and usual
`work areas . It's likely that during lunchtime , there are many 40 of the transport routing , traffic monitoring and network
`optimization based on having multiple 3 sector BTSs with 3
`locations throughout the facility where there are very few
`DAUs and 7 DRUs daisy chained together for each cell . In
`subscribers . If the indoor wireless network resources were
`properly sized during the design process for subscriber
`this embodiment , multiple three sector base stations are
`loading as it is during normal working hours when subscrib
`connected to a daisy chained DAS network .
`ers are in their normal work areas , it is very likely that the 45
`FIG . 4 is a block diagram of a Digital Access Unit ( DAU ) ,
`lunchtime scenario will present some unexpected challenges
`which contains Physical Nodes , a Local Router , and Port
`with regard to available wireless capacity and data through
`Traffic Monitoring capability according to an embodiment
`put .
`of the present invention .
`According to an embodiment of the present invention , a
`FIG . 5 is a block diagram of a Digital Remote Unit
`system for dynamically routing signals in a Distributed 50 ( DRU ) , which contains Physical Nodes , a Remote Router ,
`Antenna System is provided . The system includes a plurality
`and Port Traffic Monitoring capability according to an
`of Digital Access Units ( DAUS ) . The plurality of DAUs are
`embodiment of the present invention .
`coupled and operable to route signals between the plurality
`FIG . 6 depicts a typical topology where multiple Local
`of DAUs . The system also includes a plurality of Digital
`Routers are interconnected with multiple Remote Routers
`Remote Units ( DRUs ) coupled to the plurality of DAUs and 55 along with Traffic monitoring and Network Optimization
`operable to transport signals between DRUs and DAUs . The
`functionality according to an embodiment of the present
`system further includes one or more Base Transceiver Sta
`invention .
`FIG . 7 depicts a typical topology where multiple Local
`tions ( BTSs ) and one or more traffic monitoring units .
`According to another embodiment of the present inven
`Routers are interconnected with multiple Remote Routers
`tion , a system for dynamically routing signals in a Distrib- 60 along with Traffic monitoring at each Picocell and Network
`uted Antenna System is provided . The system includes a
`Optimization functionality according to an embodiment of
`plurality of Digital Access Units ( DAUs ) . The plurality of
`the present invention .
`DAUs are coupled and operable to route signals between the
`FIG . 8 depicts a typical topology where multiple Local
`plurality of DAUs . The system also includes a plurality of
`Routers are interconnected with multiple Remote Routers
`Digital Remote Units ( DRUS ) coupled to the plurality of 65 along with Traffic monitoring at each Picocell and Network
`DAUs and operable to transport signals between DRUs and
`Optimization functionality according to an embodiment of
`DAUs and a plurality of Base Transceiver Stations ( BTS ) .
`the present invention .
`
`

`

`US 10,750,382 B2
`
`3
`4
`Another major limitation of conventional DAS deploy
`FIG . 9 is a simplified flowchart illustrating a method of
`ments is related to their installation , commissioning and
`optimizing the DAS network according to an embodiment of
`optimization process . Some challenging issues which must
`the present invention .
`be overcome include selecting remote unit antenna locations
`FIG . 10 is a simplified flowchart illustrating a method of
`calculating KPIs and QoS for a DAS network according to 5 to ensure proper coverage while minimizing downlink inter
`ference from outdoor macro cell sites , minimizing uplink
`an embodiment of the present invention .
`FIG . 11 is a simplified flowchart illustrating an optimi
`interference to outdoor macro cell sites , and ensuring proper
`zation algorithm according to an embodiment of the present
`intra - system handovers while indoors and while moving
`from outdoors to indoors ( and vice - versa ) . The process of
`invention .
`10 performing such deployment optimization is frequently
`characterized as trial - and - error . Therefore , the results may
`DETAILED DESCRIPTION OF THE
`not be consistent with a high quality of service .
`INVENTION
`Based on the conventional approaches described herein , it
`To accommodate variations in wireless subscriber loading
`is apparent that a highly efficient , easily deployed and
`at wireless network antenna locations at various times of day 15 dynamically reconfigurable wireless network is not achiev
`and for different days of the week , there are several candi
`able with conventional systems and capabilities . Embodi
`date conventional approaches .
`ments of the present invention substantially overcome the
`One approach is to deploy many low - power high - capacity
`limitations of the conventional approach discussed above .
`base stations throughout the facility . The quantity of base
`The advanced system architecture provided by embodiments
`stations
`determined based on the coverage of each base 20 of the present invention provides a high degree of flexibility
`station and the total space to be covered . Each of these base
`to manage , control , enhance and facilitate radio resource
`stations is provisioned with enough radio resources , i.e. ,
`efficiency , usage and overall performance of the distributed
`capacity and broadband data throughput to accommodate the
`wireless network . This advanced system architecture
`maximum subscriber loading which occurs during the
`enables specialized applications and enhancements includ
`course of the workday and work week . Although this 25 ing , but not limited to , flexible simulcast , automatic traffic
`approach typically yields a high quality of service for
`load - balancing , network and radio resource optimization ,
`wireless subscribers , the notable disadvantage of this
`network calibration , autonomous / assisted commissioning ,
`approach is that many of the base stations ' capacity is being
`carrier pooling , automatic frequency selection , radio fre
`wasted for a large part of the time . Since a typical indoor
`quency carrier placement , traffic monitoring , and / or traffic
`wireless network deployment involves capital and opera- 30 tagging . Embodiments of the present invention can also
`tional costs which are assessed on a per - subscriber basis for
`serve multiple operators , multi - mode radios ( modulation
`each base station , the typically high total life cycle cost for
`independent ) and multiple frequency bands per operator to
`a given enterprise facility is far from optimal .
`increase the efficiency and traffic capacity of the operators '
`A second candidate approach involves deployment of a
`wireless networks .
`DAS along with a centralized group of base stations dedi- 35
`Accordingly , embodiments of this architecture provide a
`cated to the DAS . A conventional DAS deployment falls into
`capability for Flexible Simulcast . With Flexible Simulcast ,
`one of two categories . The first type of DAS is “ fixed ” ,
`the amount of radio resources ( such as RF carriers , LTE
`where the system configuration doesn't change based on
`Resource Blocks , CDMA codes or TDMA time slots )
`time of day or other information about usage . The remote
`assigned to a particular DRU or group of DRUs can be set
`units associated with the DAS are set up during the design 40 via software control to meet desired capacity and throughput
`process so that a particular block of base station radio
`objectives or wireless subscriber needs . Applications of the
`resources is thought to be enough to serve each small group
`present invention are suitable to be employed with distrib
`of DAS remote units . A notable disadvantage of this
`uted base stations , distributed antenna systems , distributed
`approach is that most enterprises seem to undergo frequent
`repeaters , mobile equipment and wireless terminals , por
`re - arrangements and re - organizations of various staff groups 45 table wireless devices , and other wireless communication
`within the enterprise . Therefore , it's highly likely that the
`systems such as microwave and satellite communications .
`initial DAS setup will need to be changed from time to time ,
`According to an embodiment of the present invention , a
`requiring deployment of additional direct staff and contract
`traffic monitoring unit is provided as a component of one or
`resources with appropriate levels of expertise regarding
`more elements of the system , enabling measurement of the
`50 network traffic in the network . A network optimization goal
`wireless networks .
`The second type of DAS is equipped with a type of
`and optimization algorithm is also provided so that based on
`network switch which allows the location and quantity of
`traffic measurements , which is typically a function of the
`DAS remote units associated with any particular centralized
`number of users on the system , performance of the network
`base station to be changed manually . Although this approach
`is optimized using the goal and associated algorithm .
`would appear to support dynamic DAS reconfiguration 55
`As an example of traffic monitoring , the system could
`based on the needs of the enterprise or based on time of day ,
`track the power of the down link or the power of the uplink .
`it frequently implies that additional staff resources would
`Another example , would include some signal processing ,
`need to be assigned to provide real - time management of the
`including examining certain control signals , for example ,
`network . Another issue is that it's not always correct or best
`pilot signals sent by mobile devices . By locking onto these
`to make the same DAS remote unit configuration changes 60 control signals , the traffic monitor can obtain information on
`back and forth on each day of the week at the same times of
`the number of users using various components of the system .
`day . Frequently it is difficult or impractical for an enterprise
`A distributed antenna system ( DAS ) provides an efficient
`IT manager to monitor the subscriber loading on each base
`means of utilization of base station resources . The base
`station . And it is almost certain that the enterprise IT
`station or base stations associated with a DAS can be located
`manager has no practical way to determine the loading at a 65 in a central location and / or facility commonly known as a
`given time of day for each DAS remote unit ; they can only
`base station hotel . The DAS network comprises one or more
`guess the percentage loading ,
`digital access units ( DAUS ) that function as the interface
`
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`

`US 10,750,382 B2
`
`5
`6
`present invention and provides an example of a data trans
`between the base stations and the digital remote units
`port network , traffic monitoring and network optimization
`( DRUS ) . The DAUs can be collocated with the base stations .
`scenario between a 3 sector Base Station and multiple
`The DRUs can be daisy chained together and / or placed in a
`DRUs . In this embodiment , the DRUs are daisy chained
`star configuration and provide coverage for a given geo
`graphical area . The DRUs are typically connected with the 5 together to achieve coverage in a specific geographical area .
`DAUs by employing a high - speed optical fiber link . This
`Each individual sector covers an independent geographical
`approach facilitates transport of the RF signals from the base
`area , which is identified as a Cell . Although embodiments
`stations to a remote location or area served by the DRUS . A are discussed in terms of optimization of DAS networks , the
`typical base station comprises 3 independent radio
`term optimization is properly understood to include perfor
`resources , commonly known as sectors . These 3 sectors are 10 mance improvements in comparison to conventional sys
`typically used to cover 3 separate geographical areas without
`tems , even if complete optimization is not achieved . Thus ,
`creating co - channel interference between users in the 3
`optimization does not require the maximum values for traffic
`management metrics , but also includes distribution of traffic
`distinct sectors .
`Traffic monitoring in a DAS network is provided by
`that improves system performance while remaining short of
`embodiments of the present invention , which has not been 15 maximum performance .
`performed in conventional systems . As described herein , the
`FIG . 1 depicts a DAS system employing multiple Digital
`traffic monitoring unit can be implemented as a stand - alone
`Remote Units ( DRUs ) and multiple Digital Access Units
`unit in conjunction with one or more system components ,
`( DAUS ) . In accordance with the present invention , each
`including DAUS , DRUS , a BTS , a BTS hotel , or the like .
`DRU provides unique information associated with each
`Once traffic resources are aggregated into eNodeB hotels , 20 DRU which uniquely identifies uplink data received by that
`the discrete resources of a single eNodeB are still allocated
`particular Digital Remote Unit .
`to a specific set of antennas associated with that eNodeB and
`One feature of embodiments of the present invention is
`providing coverage to a specific geographic area . The traffic
`the ability to route Base Station radio resources among the
`resources are fixed , i.e. , only the resources associated with
`DRUs or group ( s ) of DRUs . In order to route radio resources
`a specific eNodeB can be allocated to the antennas associ- 25 available from one or more Base Stations , it is desirable to
`ated with that eNodeB . However , because the eNodeBs are
`configure the individual router tables of the DAUs and
`collocated in an eNodeB hotel , the system can use the
`DRUs in the DAS network . This functionality is provided by
`aggregated traffic resources of the discrete eNodeBs as a
`embodiments of the present invention .
`single , pooled traffic resource that can be allocated accord
`The DAUs are networked together to facilitate the routing
`ing to various algorithms . Assumptions are typically predi- 30 of DRU signals among multiple DAUs . The DAUs support
`cated on worst - case traffic assets in all areas , network design
`the transport of the RF downlink and RF uplink signals
`is wasteful 99 percent of the time , inevitably resulting in
`between the Base Station and the DRUs . This architecture
`over- or under - provisioning of fixed resources . Traffic
`enables the various Base Station signals be transported to
`resources either go unused ( idle channels ) , or are under
`and from multiple DRUs . PEER ports are used for inter
`provisioned and are insufficient to handle the offered traffic . 35 connecting DAUs and interconnecting DRUs .
`Both circumstances give rise to the same outcome : lost
`The DAUs have the capability to control the gain ( in small
`revenue and lost opportunity . When a site's traffic resources
`increments over a wide range ) of the downlink and uplink
`are idle and unused , the traffic asset fails to provide an
`signals that are transported between the DAU and the base
`optimal return on investment . But a site that lacks sufficient
`station ( or base stations ) connected to that DAU . This
`capacity to support the offered traffic at any point during the 40 capability provides flexibility to simultaneously control the
`day garners dropped calls , lost revenue opportunity , and
`uplink and downlink connectivity of the path between a
`dissatisfied customers . The traffic information derived from
`particular DRU ( or a group of DRUs via the associated DAU
`an extensive sensor network will be used to dynamically
`or DAUS ) and a particular base station sector .
`allocate the traffic resources to the required geographical
`Embodiments of the present invention use router tables to
`areas only for the time period the service is needed . Once the 45 configure the networked DAUs . The local router tables
`service is supplied and the traffic sensor network determines
`establish the mapping of the inputs to the various outputs .
`that the traffic resources are no longer required , they are
`Internal Merge blocks are utilized for the Downlink Tables
`returned to the resource pool for reallocation . The entire
`when the inputs from an External Port and a PEER Port need
`network automatically reconfigures itself based on the per
`to merge into the same data stream . Similarly , Merge blocks
`ceived ( sensed ) need or in the event of disruption due to 50 are used in the Uplink Tables when the inputs from the LAN
`natural or manmade events . Geographic load balancing
`Ports and PEER Ports need to merge into the same data
`using DAS is recognized as a new approach for traffic load
`stream .
`balancing which provides dynamic load redistribution in real
`The remote router tables establish the mapping of the
`time according to the current geographic traffic conditions .
`inputs to the various outputs . Internal Merge blocks are
`It can be used to improve the performance for any distrib- 55 utilized for the Downlink Tables when the inputs from a
`uted systems containing non - uniformly distributed traffic ,
`LAN Port and a PEER Port need to merge into the same data
`especially for resolving traffic hot spots .
`stream . Similarly , Merge blocks are used in the Uplink
`The network's performance ( expressed by the number of
`Tables when the inputs from the External Ports and PEER
`KPIs ( Key Performance Indicators ) from different parts of
`Ports need to merge into the same data stream .
`the network ) determines the QoS values . Different operators 60
`As shown in FIG . 1 , the individual base station sector's
`may have different defined business goals and different
`radio resources are transported to a daisy - chained network
`services of interest . Based on these considerations , efficient
`of DRUs . Each individual sector's radio resources provide
`and cost effective network performance management varies
`coverage to an independent geographical area via the net
`from operator to operator . Therefore , QoS metrics could be
`worked DRUS . FIG . 1 demonstrates how three cells , each
`65 cell comprising an independent network of 7 DRUs , provide
`defined and mapped to a set of KPIs .
`An embodiment shown in FIG . 1 illustrates a basic DAS
`coverage to a given geographical area . A server is utilized to
`network architecture according to an embodiment of the
`control the switching function provided in the DAS network .
`
`

`

`US 10,750,382 B2
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`7
`8
`The DAUs control the routing of data between the base
`Referring to FIG . 1 and by way of example , DAU 1 ( 102 )
`station and the DRUs . Each individual data packet is pro
`receives downlink signals from BTS Sector 1 ( 101 ) . DAU 1
`vided with a header that uniquely identifies which DRU it is
`translates the RF signals to optical signals and the optical
`associated with . The DAUs are interconnected to allow
`fiber cable 103 transports the desired signals to DRU 2
`( 104 ) . Optical cable 105 transports all the optical signals to 5 transport of data among multiple DAUs . This feature pro
`vides the unique flexibility in the DAS network to route
`DRU 3 ( 106 ) . The other DRUs in the daisy chain are
`signals between the sectors and the individual DRUs . A
`involved in passing the optical signals onward to DRU 1
`server is utilized to control the switching function provided
`( 107 ) . DAU 1 ( 102 ) is networked with DAU 2 ( 108 ) to allow
`in the DAS network . Referring to FIG . 2