Fracking for 5G: Reconfigurable RF and High-Efficiency

Fracking for 5G: Reconfigurable RF and High-Efficiency Millimeter-wave Circuits to Find Elusive Spectrum Dr. James Buckwalter RF & Mixed-circuit Integrated Circuits Laboratory University of California – Santa Barbara

James Buckwalter, Corporate Affiliates Board Meeting, April 2015

Mixed-Signal and RF Integrated Circuits

•  HSIC Lab at UCSB •  Fundamental investigation of

RF and mixed-signal integrated circuit techniques that enable high-speed/high-frequency applications.

•  1 Post-doctoral Scholar •  10 Ph.D. Graduate Students •  Alumni: •  8 Ph.D. Alumni, 3 M.S. Alumni

Silicon RF/ Microwave / Millimeter-wave

Wireline/ Silicon Photonics

High-Speed Mixed Signal

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Why UCSB ECE? •  UCSB ECE MOVES DATA!

•  Traditional strengths in •  Photonics: backhaul and intra/interchip communication •  High-speed, solid-state devices

•  These strengths are complemented with an •  Emphasis in wireless communication. •  Emphasis on CMOS integrated circuits.

•  Future integrated circuit technologies will leverage III-V and other material systems to enhance CMOS. UCSB is posed to develop leadership.

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Is Spectrum Inexhaustible? •  Number of wireless devices vastly exceeds the world’s

population and is increasing rapidly!. •  New devices are coming such as wearable electronics,

sensors, and radars. More devices in the same area.

1 EB = 1B Gigabytes •  Traffic is projected at 5 EB per

month in 2015 •  01/20/14: British Telecom

demonstrates 1.4 Tb/s at 5.7 b/s/Hz; estimates 35% growth in bandwidth per year.

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What drives increase in data demand? Cloud applications, Internet of Things 1) Data Center Traffic: Optical transport > 10 Tb/s 2) Mobile Content Delivery: Wireless > 1 Gb/s


Beyond 4G?

•  Look back at history licensed operation •  2G Cellular – launched in 1991

•  Birth of GSM and CDMA in wireless communications •  Maximum data rate (EDGE) of 1 Mb/s.

•  3G Cellular – launched in 2001 •  Movement towards integrated data services over cellular •  Maximum data rate (HSPA+) of 28 Mb/s.

•  4G Cellular – launched in 2011 •  Transition to IP based communication •  Extensive use of MIMO and signal processing •  Peak data rates (currently) of > 100 Mb/s

•  What’s next for 2021?

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4H?

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Where will the CAPACITY come from? •  RF: Evolution towards more fluid use of available

spectrum •  Carrier aggregation •  Simultaneous licensed/ unlicensed operation

•  Millimeter-wave: Use of beamforming to exploit the spatial dimension for short wavelengths •  50 x BW in mm-wave bands •  5G 30 GHz bands •  60/140 GHz for short range •  70/80 GHz (E-band) for point-to-point links

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Market does not jump to higher frequency bands until everything is squeezed from the lower frequency bands. Is it time?

Source: Qualcomm

Source: R. Heath


Circuit Challenges for RF Hardware •  Modern Cellphone 4G (LTE)

•  Multiantenna / Multistandard / Multiband solutions •  1 W transmit, 20 MHz channels, OFDM (peak 300 Mb/s) •  700/850/1700/1900/2100/2600 MHz •  WiFi, Bluetooth, Near-field

•  How do you go 10X in existing bands? Most signal processing tricks have been exploited!

•  MIMO è Massive/Multi-User MIMO (10x improvement possible) •  Small Cells è Offload data traffic onto broadband network •  Carrier Aggregation: Capacity expands with number of bands.

More bands, more interference. e.g. Qualcomm announces LTE-U chip for seamless use of LTE-A and unlicensed 5 GHz bands. 3x20 carrier aggregation.

•  Software-defined Radios – ad hoc operation •  Cognitive Radio: Sense (Spectrum), Discriminate (Blockers),

Mitigate (Interference), Learn (Patterns)

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Trends in IC Design

•  RF (< 6 GHz) circuit design is blending with mixed-signal design techniques to produce reconfigurable circuitry/ software defined radios. Golden age for RF-CMOS Design!

•  CMOS is pushing to millimeter-wave bands. Mm-wave/Terahertz systems are not necessarily limited solely by IC cost. Performance demands InP or GaN devices.

•  Blending of heterogeneous IC processes: InP on CMOS or GaN on CMOS for phased arrays.

Everything starts with devices


Conclusions

•  Wireless access is reaching a tipping point. •  Improvements in wireless capacity will require

digging deeper from within the congested RF spectrum for available spectrum.

•  Opportunities to get plenty of spectrum at mm-wave bands at great cost to industry.

•  At the same time, CMOS is reaching a point of diminishing return for scaling.

•  Enhancing CMOS through materials and packaging approaches is a critical part of future mm-wave systems.

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Questions?

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Fracking for 5G: Reconfigurable RF and High-Efficiency