MultiMode Mobile Device Trends and Challenges

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Multi-Mode Mobile Device Trends and Challenges

• Aarno Pärssinen
• Nokia Research Center
• aarno.parssinen_at_nokia.com

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Applications for mobile consumers

• Connecting people and communities
• Voice call and messaging
• Email, web 2.0
• Broadband multimedia
• Personal content sharing
• Broadcast/Webcast
• Interactive multimedia
• Data synchronization, mobile enhancements
• Location based services
• Ubicomm

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Radios for various purposes

• Protocols
• Cellular, BT, WLAN
• Broadcast (FM mobile TV)
• Location (GPS)
• Broad-band mobility (LTE/WiMax)
• Local applications and services (ULP BT / RFID)
• Scalability to different markets
• Different market regions segments
• Capacity towards higher data rates
• Connect everything

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Origins of front-end parameters

• Protocols, control plane and RF schedule
• Antenna interface ( of bands, RF performance)
• ASIC interface

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Radio spectrum in mobile use
Most bands are regional or contain regional
sub-bands
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Potential RF Variants for Global Coverage
1) Only one standard for the application given 2)
Band groups in MB-OFDM
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Wide-Area Broadband
1) WiMAX mobile profile, 2) Fractional Frequency
Reuse
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Multi-standard RF paradigm

• Antenna-to-antenna isolation finite
• All radios are coupled
• Strong internal interferers in the device
• Additional non-standard specifications
• blocking and harmonics from another TX
• wide-band noise from other TX
• intermodulation due to other internal TX and
  external/internal blocker
• several clock domains

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GPS Example

• GSM uplink with maximum output power _at_900.0 MHz
• WLAN transmitting with maximum power _at_2475.5 MHz

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IIP2 requirement for GPS

• Intermodulation due to own TX power and external
  blocker

GPS N(RX) -108 dBm IMD,max (RX) -123
dBm GSM P(TX) 33 dBm P(TX _at_GPS ANT) 18
dBm WLAN _at_1m P(TX) 20 dBm P(TX _at_GPS ANT) -20
dBm IMD2/GPS BW ratio 8 GPS IMD2, max
tot -114 dBm IIP2_at_ANT, specs 112
dBm G(ANT-MIXER) 20 dB IIP2(mixer) 50 dBm
-gt L(GSM)L(WLAN) 62 dB
LNA response
LNA response
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Example Wide-band noise
WCDMA P(RX) -117 dBm N(RX) _at_3.84MHz -99
dBm WLAN P(TX) 20 dBm P(TX _at_WCDMA ANT) 5
dBm -67 dBm/Hz N(WB) specs -40 dBr -107
dBm/Hz N(WB) _at_WCDMA band -41 dBm N(WB)
requirement -114 dBm ?N(WB) 73 dB
WCDMA
WLAN
WLAN spectrum mask
?N(WB)
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Interference requirements

• TX source and RX victim

TX
RX
Design margin
critical
small
moderate
large
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Key performance elements

• Antenna isolation
• RX Filtering and TX transmission mask
• Sensitivity especially in cellular communications
  and GPS
• Enhanced receiver linearity
• Getting power also to aether
• Power consumption
• Continuous connection to internet through
  different protocols
• Minimize losses in the front-end

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Holistic integration

• Antenna placement
• Front-end losses especially at band edges
• Robustness (mismatch, thermal, )
• Stable impedance environment for filters
• Maintain antenna efficiency (loading)
• Human interaction

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Getting power out (Examples)
3) Specs 24 (1/-3) dBm 4) Peak values average
less due to pwr ctrl
1) Wiring and FE loss at band (edge) 2)
Reflection loss and PA load pull
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State-of-the-art Device

• WLAN 802.11b/g
• WCDMA/HSDPA 2100
• 4-band EDGE
• BT 2.0
• FM
• GPS
• Volume 96 cm3
• Weight 128 g

WCDMA GSM RF
GSM PA
WCDMA PA
MODEM
EM AUDIO
FM
APPLICATION PROCESSOR
WLAN
BT
GPS
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It is just beginning

• Ultimate complexity
• of bands systems
• Ultimate performance
• Cellular GPS
• Ultimate functionality
• Antenna, filters, PA
• Power detector, coupler, etc.
• System controls
• Performance controls
• Ultimate integration
• Module Packaging

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Scenario towards full SDR

• Generic SDR RF BB will make it ?
• SDR front-ends
• System performance
• Antenna placement
• FE adjustability (up to 10-20 bands)
• Separate front-ends or one switched ?
• SDR ASIC
• Is interference still tolerable?
• Losses to antennas
• Flexible spectrum usage

2G 3G
GPS
WLAN
BT
DVB-H
FM
WLAN DIV
3G DIV
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Control challenge

• Interfaces in multimodal operation

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Conclusion

• Multi-standard radio devices play a major role in
  mobile devices excluding the simplest low-end
  devices
• Increased number of RF bands and wide-band
  systems will make the scene even more complex
• SDR platform must meet product performance,
  scalability, form factor and control requirements
  in a hostile local radio environment
• RF from silicon to aether and back is a challenge
  beyond the SDR ASIC integration
• Dependencies in RF frequency agility require
  holistic co-design of system, ASIC and front-end

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