This document discusses Analog Devices' solutions for 3G femtocell radios. It begins with an overview of Analog Devices and the challenges facing femtocell deployment. It then discusses market drivers and risks, operator expectations of low cost and ease of use, and considerations for reducing the femtocell bill of materials cost below $100. The document presents Analog Devices' integrated transceiver and converter chips that enable a low-cost multi-band 3G femtocell design with minimal external components and easy calibration. It concludes by discussing potential multimode femtocell support and an initial WiMAX femtocell design.
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A 3G Femtocell Radio - Analog Devices VON Boston Networking Conference Oct 29 2007
1. The World Leader in High Performance Signal Processing SolutionsThe World Leader in High Performance Signal Processing Solutions
3G Femtocell
Radio
VON Boston
David J. Donovan
Wireless Infrastructure Business Development
Analog Devices, October 29, 2007
2. 2
Agenda
Brief Overview of ADI
Femtocell Identity Crisis
Market Drivers & Deployment Risks
Specification Issues & Challenges
Operator expectations
Semiconductor RF-IF Solution
BOM Costs
Analog Devices 3G Femtocell Radio October 29 , 2007
3. 3
PLATFORMS
AudioAudioAudio
ControlControlControl
VideoVideoVideo
DataDataData
CORE TECHNOLOGYCORE TECHNOLOGY
Application Expertise ● Development Tools
PortableMediaDevices
WirelessInfrastructure
Computing&Gaming
DigitalEntertainment
AdvancedTV
Medical
AudioAudioAudio
ImagingImagingImaging
MonitoringMMonitoringonitoring
EXPERTISE
Automotive
Industrial
ProcessingPProcessingrocessing
ADI At A Glance
A leadership portfolio of core technology and signal processing systems
expertise that is leveraged to create competitive advantage for our customers
SensingSensingSensing SensorySensorySensory
AlgorithmsAAlgorithmslgorithms
A P P L I C A T I O N S
MEMSMEMS
DSPDSPAmplifierAmplifierDataData
ConverterConverter
PowerPower
ManagementManagement RF ICRF IC
InterfaceInterfaceInterface
CommunicationCommunicationCommunication
WirelessWirelessWireless
Analog Devices 3G Femtocell Radio October 29 , 2007
4. 4
Femtocell Identity Crisis?
Basestation
High performance
High reliability
Medium cost
Low volume
Single standardFemtocell
High performance
High reliability
Low cost
High volume
Multi-standard
Handset
Lower performance
Very low cost
Very high volume
Multi-standard
Cost
Performance
Photo Sources: Ericsson, Alcatel-Lucent, Nokia
Analog Devices 3G Femtocell Radio October 29 , 2007
6. 6
Femtocell
<$100 BOM
Femtocell
<$100 BOM
Simplified Femtocell Network Integration
RF-IF
DSL
Router IP
Network
IP
Network
RNC functions for Radio Resource
Management shifted to Femtocell
BB
Analog Devices 3G Femtocell Radio October 29 , 2007
Home Core Network
7. 7
Market Drivers
Consumer Benefits--- Better Indoor Coverage
Inadequate in-door coverage - top consumer complaint of their
cellular service provider
Lower PA power levels in handset
Operator Benefits--- Reduces Capex & Opex
Improves network capacity and coverage
Pushes backhaul service to consumer BB IP network
Consolidate services – Especially attractive to combined
broadband/wireless provider
Reduce churn rate by increased service and user capital
investment
Analog Devices 3G Femtocell Radio October 29 , 2007
8. 8
Deployment Risks & Challenges
Location/Registration
E911/GPS adds cost and complexity
Radio Network management
Narrowband GSM signals are blockers to adjacent cells
Potential network interference
(W)CDMA systems are easier to manage
VOIP WiFi Threat
Similar operator objectives – different model
More expensive dual mode phone vs. CAPEX
Challenges above are similar
Repeaters & DAS can address the critical coverage
issue, but does nothing for capacity, bundling service
Analog Devices 3G Femtocell Radio October 29 , 2007
9. 9
Deployment Risks & Challenges cont.
Backhaul architecture – several options
IP protocols skip the traditional cellular network
Optimum solution an unknown but will impact the degree of the
problems below…..
Network Synchronization
BTS needs accurate clock and sync to network
Timing module could have negative impact on BOM
IEEE 1588 scheme for sync to IP backhaul
Needs further study
QoS risks
Backhaul (Broadband pipe) management to arbitrate users/data
rate may not be simple
Bigger issue for wireless operator with no ties to broadband
provider
Analog Devices 3G Femtocell Radio October 29 , 2007
10. 10
3GPP Base Station Classes:
First specified in Release 6
Wide Area Base Stations: Macro Cell Scenario
<20km cell, 70 dB coupling loss UE-MS
Medium Area Base Stations: Micro Cell Scenario
1km – 3km, 53 dB coupling loss UE-MS, <38dBm
Local Area Base Station: Pico Cell Scenario
100m – 300m, 45 dB coupling loss UE-MS, <24dBm
Home Base Station / Access Points have not been considered
in Release 6 and onwards yet
Home Access Scenario (20m), 10dBm – 20dBm
Radio Requirements still depend on system simulations & trials
Analog Devices 3G Femtocell Radio October 29 , 2007
11. 11
Base Station Definitions
Femtocells are also referred to as Home Access Points and
may be part of a broadband gateway platform.
Picocell Basestation Femtocell Basestation
Voice & Data Service
250 mW / 6 kg
~80 Voice Users
HSDPA 14.4 Mbps
HSUPA 7.2 Mbps
10mW – 100mW / 1 kg
20mW typical (+13dBm)
4 Voice & Data Users
HSDPA 14.4 Mbps
HSUPA 7.2 Mbps
Form Factor & User Capacity
Photo Sources: Andrew, Ubiquisys
Analog Devices 3G Femtocell Radio October 29 , 2007
12. 12
3GPP WCDMA UE vs. BS RF Specifications
3GPP Rx Specification Unit UE 25.101 BS 25.104
Reference Sensitivity 12.2kbps dBm -117 -107
Maximum Channel Power dBm -25 ----
Dynamic Range Test Level (AWGN 18dB above wanted) dBm ---- -77
Adjacent Channel WCDMA 5MHz Offset dBc 39 63
In Band WCDMA Blocking 10 MHz Offset dBc 48 71
Out of Band CW Blocking 20 MHz Offset dBc ---- 86
Out of Band CW Blocking 60 MHz Offset dBc 74 ----
Out of Band CW Blocking 85 MHz Offset dBc 89 ----
Narrow Band GMSK Blocking 2.7MHz Offset dBc 41 64
Wide Band Intermodulation CW 10MHz + WCDMA 20MHz dBc 58 63
Narrow Band Intermodulation CW 3.5MHz + GMSK 5.9MHz dBc 54 64
3GPP Tx Specification Unit UE 25.101 BS 25.104
Maximum Power dBm 24 <24
Maximum Power Accuracy +/- dB 2 2.5
Minimum Power Control Step dB 1 0.5
1dB Step Accuracy +/- dB 0.5 0.5
10dB Step Accuracy +/- dB 2 2
Power Control Range dB 74 18
ACLR 5MHz dB 33 45
ACLR 10MHz dB 43 50
Tx Noise in own Rx band dBm/Hz -132
EVM % 12.5 17.5
Peak Code Domain Error dB -15 -33
Phase Discontinuity deg 30 ----
Analog Devices 3G Femtocell Radio October 29 , 2007
13. 13
No formal spec for this platform
The femtoforum.org was organized to promote deployment of
Femtocells worldwide through collaboration and
interoperability
Whole wireless infrastructure eco-system participates
Goal is to make a spec recommendation to 3GPP specific to
home base stations
Femtocell Specifications
Analog Devices 3G Femtocell Radio October 29 , 2007
14. 14
Operator Expectations
Operators require a self-managed plug & play femto layer at
typical mobile subscriber acquisition cost points
BOM COST
TRX + BB IC BOM
<$70
Roadmap to
<$40
Ease of Network
Integration
2G & 3G bands
scanning
Autonomous
Power Control &
Self-Configuration
Manufacturability
Single-Point
Radio Calibration
Minimum
Production Time
Analog Devices 3G Femtocell Radio October 29 , 2007
15. 15
Considerations for a Low
FemtoCell BOM
Minimal manufacturing costs (radio calibration)
Highly integrated silicon functionality
Multi-band operation
Leverage existing market economy components (eg handset)
Multiple functions in one package
Minimizing component count (glue-less interfaces, integrated
passives)
Power consumption
Footprint
Analog Devices 3G Femtocell Radio October 29 , 2007
16. 16
Radio Calibration
Single point calibration is possible and results in an
accuracy better than the competition
Multi-point calibrations [2 - 6 points] add to TCO
An integrated RMS power detector is designed to meet
the stringent power control requirements of WCDMA
systems
Representative Output Power Curve
-50
-40
-30
-20
-10
0
10
20
30
40
0 0.5 1 1.5 2
Vset (Volts)
OutputPower(dBm)
Representative
1-Point Calibration Error
-1.00
-0.50
0.00
0.50
1.00
5 10 15 20 25 30 35
Output Power (dBm)
Error(dB)
Analog Devices 3G Femtocell Radio October 29 , 2007
17. 17
TRX Band Coverage Requirements-UMTS
UMTS Bands Uplink Downlink
Tx/Rx Data
Support
Band Monitor
Support
I 1920 - 1980 2110 - 2170
ADF4602,
ADF4602-5
ADF4602,
ADF4602-5
II 1850 - 1910 1930 - 1990
ADF4602,
ADF4602-5
ADF4602,
ADF4602-5
III 1710 - 1785 1805 - 1880
ADF4602,
ADF4602-5
ADF4602
ADF4602-5
IV 1710 - 1755 2110 - 2155 No No
V 824 - 849 869 - 894
ADF4602,
ADF4602-5
ADF4602
ADF4602-5
VI 830 - 840 875 - 885
ADF4602,
ADF4602-5
ADF4602
ADF4602-5
VII 2500 - 2570 2620 - 2690 No No
VIII 880 - 915 925 - 960
ADF4602,
ADF4602-5
ADF4602,
ADF4602-5
IX 1749,9 - 1784,9 1844,9 - 1879,9
ADF4602,
ADF4602-5
ADF4602,
ADF4602-5
X 1710 - 1770 2110 - 2170 No No
Analog Devices 3G Femtocell Radio October 29 , 2007
18. 18
2007 Development Platform:
Integrated Converter MxFE & Integrated Radio
DATA
MUX
&
LATCH
SPI
REGISTERS
AUX DAC
AUX ADC
DAC
DAC
2X
Inter-
polation
LATCH
&
DEMUX
ADC
ADC
I/O Interface
Configuration
AUX DAC
AUX ADC
CLOCK
DISTRIBUTION
PLL
...
...
AUX DAC
.. .
DC
DC
PA
DAC
DAC
ADC
÷2
ADF TRX
Gain
Control
PDLO
PDLO
Attn
I+Q
÷2
I+Q
4 Bit
GPIO
MxFE
Synth-
esizers
VCT
CXO
AFC
I
I
Q
Q
3 Wire
Bus
Digital
Baseband
ADFTRX Radio Technology
Highly integrated Transceiver
No external SAW filters (apart from Duplexer)
4 Code Transmit compatible (4+ users)
Accurate Integrated power control
Low Power RF CMOS
6x6mm 32 pin package
MxFE AD986x
High Performance ADCs – DACs optimized for
base station applications
Highly Integrated Smart Partitioning
64 pin LFCSP
26MHz
Clock
Buffer
IP Link
ADL5320
ADL5541
CLK
Analog Devices 3G Femtocell Radio October 29 , 2007
19. 19
UMTS Radio Transceiver
Single Chip Tri-band 3G Transceiver
3GPP 25.104 Release 6 WCDMA/HSDPA
Local Area Class BS in Band 1-3,5,6,8,9
WCDMA &GSM Monitoring of Bands 1-3,5,6,8,9
Minimal external components
No Tx SAW or Rx Inter-stage SAW filters
Integrated Fast RMS power detector
Integrated Power Management (3.2-5.5V input)
Integrated Synthesizers incl. PLL loop filters
Integrated PA bias control DACs/GPOs
Easy to use with minimal calibration
Automatic fast Tx power control
Automatic Rx offset control
Simple gain, frequency, mode programming
Low supply current
35mA typical Rx current
40-100mA Tx current (varies with Pout)
6x6mm LFCSP package
DC Offset
Correction
DC Offset
Correction
ADF4602
LO Generator
RMS
Detector
Gain Control
System
Loop
Filter
Frac N
Synth
LO Generator
Loop
Filter
Frac N
Synth
TX_Pwr_
Control
TX_Pwr_Control
TX_Pwr_Control
TX_Pwr_Control
[Bus]
Serial
InterfaceLDO1 LDO2 LDO3 LDO4 LDO5
TX_Pwr_Control
TX PLL
RX PLL
TX Power Management System
RX_LO_LB
RX_LO_LB
19.2
MHz
26
MHz
TXRF
Selectable Bandwidth baseband filters
TXBBIB
TXBBI
TXBBQ
TXBBQB
RXBBI
RXBBIB
RXBBQ
RXBBQB
REFIN
RXLBRF
RXHB2RF
RXHB1RF
PDET
VDD1 VSUP8
I Chan
Q Chan
VSUP6
VSUP7
Analog Devices 3G Femtocell Radio October 29 , 2007
20. 20
IOUT+ B
IOUT- A
IOUT+ A
IOUT- B
VIN- B
VIN+ B
VIN- A
VIN+ A
CLKOUT1
DATA
MUX
&
LATCH
SPI
REGISTERS
AUX DAC
AUX ADC
SPI
DAC
DAC
2X
Inter-
polation
LATCH
&
DEMUX
ADC
ADC
I/O Interface
Configuration
AUX DAC
AUX ADC
TX Sync
RX Syc
Flexible
I/O
Bus
[0:23]
OSC 1
CLOCK
DISTRIBUTION
PLL
.
..
.
..
AUX DAC
.
..
Single Chip Dual Rx ADC
& Tx /DAC
Dual 10b/12b, 65MSPS ADC
Dual 10b/12b, 130MSPS DAC
3 Channels of Analog Auxiliary I/O
ADC 65MSPS
DAC 130MSPS
Digital Test Modes
Power Down Modes
Adjustable Interface Timing
Small footprint 64 Lead LFCSP
lead-free package
UMTS IF Converter
Analog Devices 3G Femtocell Radio October 29 , 2007
21. 21
ADFTRX Transceiver
Power Detect
3GPP Band 1 DL
Monitor 850-900
Monitor 1800-2100
3GPP Band 1 UL
3G Local Area / Home Area BTS
Radio – Proposal
B1 UL
1900 Rx
1800 Rx
900 Rx
850 Rx
B1 DL
B1 DL
PA
match
attn
match
match
ADC
ADC
DAC
DAC
AD9862/AD9863
Complete Radio Module including PA options
Level plan depends on required antenna output power
Analog Devices 3G Femtocell Radio October 29 , 2007
23. 23
WiMAX Femtocell
Highly integrated CPE radio transceiver
External LNA and PA allow flexibility in system design
Digital baseband complexity similar to the UMTS
Femtocell
ADL5523
Balun
Balun
FPGA
ASIC
Pusle Shape
Filters
Sample
Rate
Conversion
FEC
Network
Processor
TigerSHARC
Interface
IP Backhaul
ADL5571
AD9352
DSP/
FPGA
Analog Devices 3G Femtocell Radio October 29 , 2007
24. 24
Multimode Femtocells
UMTS/GSM, CDMA Femtocells designed to pico or
macro BTS specs
Receive band blocking spec in GSM is challenging
Is the business case sound for investments in
multimode Femtocells?
ADC
DAC
DAC
Pusle Shape
Filters
Sample
Rate
Conversion
FEC
Network
Processor
TigerSHARC
Interface
ASIC
AD9862
ADL5350
VCO
ADC
DAC
DAC
DAC
ADC
ADC
DAC
DAC
ADC
÷2
ADFTRX
Gain
Control
PDLO
PDLO
I+Q
÷2
I+Q
4 Bit
GPIO
Synth-
esizers
3 Wire
Bus
26MHz
Clock
Buffer
VCT
CXO
SAW
ADC
AD9874
GSM 850
GSM 900
DCS
PCS
UMTS
ADL5523
ADL5525
ADL5541
GSM 850
GSM 900
DCS
PCS
UMTS
ADC
DAC
DAC
Pusle Shape
Filters
Sample
Rate
Conversion
FEC
Network
Processor
TigerSHARC
Interface
ASIC
AD9862
ADL5350
VCO
ADC
DAC
DAC
DAC
ADC
ADC
DACDAC
DACDAC
ADC
÷2
ADFTRX
Gain
Control
PDLO
PDLO
I+QI+Q
÷2
I+QI+Q
4 Bit
GPIO
4 Bit
GPIO
Synth-
esizers
3 Wire
Bus
26MHz
Clock
Buffer
VCT
CXO
SAW
ADC
AD9874
GSM 850
GSM 900
DCS
PCS
UMTS
ADL5523
ADL5525
ADL5541
GSM 850
GSM 900
DCS
PCS
UMTS
AD8349
DAC
DAC
FPGA
ASIC
Pusle Shape
Filters
Sample
Rate
Conversion
FEC
Network
Processor
TigerSHARC
Interface
Dual 10 bit 125 MSPS
ADL5541
Main
Diversity
PLL
0o
90
o
AD8342
ADL5350
ADL5221
ADL5523
ADL5523
ADF436
0
ADF436
0
ADL5530
IF ~ 100 to 200 MHz
AD9510
Clock
dist
PLL
AD9549
Clock
synch
Network clock in26 MHz
VCXO
ADC
ADC
AD6652-65
ADL5322/23
Pout ~ 24 dBm
ADL5521
AD9763
Diversity IF to Baseband Receiver
IP Backhaul
ADSP- BF536
ADL8
362
ADL5
500
ADuC70XX
Precision
Microcontroller
RX Gain
PA
AD8349
DAC
DAC
FPGA
ASIC
Pusle Shape
Filters
Sample
Rate
Conversion
FEC
Network
Processor
TigerSHARC
Interface
Dual 10 bit 125 MSPS
ADL5541
Main
Diversity
PLL
0o
90
o
AD8342
ADL5350
ADL5221
ADL5523
ADL5523
ADF436
0
ADF436
0
ADL5530
IF ~ 100 to 200 MHz
AD9510
Clock
dist
AD9510
Clock
dist
PLL
AD9549
Clock
synch
AD9549
Clock
synch
Network clock in26 MHz
VCXO
ADC
ADC
AD6652-65
ADL5322/23
Pout ~ 24 dBm
ADL5521
AD9763
Diversity IF to Baseband Receiver
IP Backhaul
ADSP- BF536
ADL8
362
ADL5
500
ADuC70XX
Precision
Microcontroller
RX Gain
PA
DSP/
FPGA
Analog Devices 3G Femtocell Radio October 29 , 2007
25. 25
Semiconductor BOM Cost v. Data Rate
Cost
DataRate
GSM/EDGE
HR
UMTS
HR UMTS
/EDGE
WiMAX
EVDO
FR
UMTS
FR UMTS
EV-DO
WiMAX
EV-DO
CDMA 1X
FR UMTS
/ EDGE
Singleradio
Multipleradios
Half Rate
Full Rate
Analog Devices 3G Femtocell Radio October 29 , 2007
26. 26
Summary
Semiconductor vendors can play a key role in the cost
reduction and migration of Femtocells
Future proofing solutions, integrations
Design for manufacturing, radio calibration
Operators can influence their own cost base
Be reasonable in requirements
A Femtocell spec will help, e.g. output power requirements vary
Trials will help codify the specs
Work with semi vendors to achieve best performance at most
reasonable cost and mitigate risk
Next phase is cost reduction and spec rationalization
ADI solutions
Analog Devices 3G Femtocell Radio October 29 , 2007