Circuits for Future Radio Systems

Circuits for Future Radio
Circuits for Future Radio Systems, CCCD Workshop 2004, September 2004
Systems
Jiren Yuan
Professor in Circuit Design, Director of CCCD
Department of Electroscience
Lund University, Lund, Sweden
jry@es.lth.se
J. Yuan, Dept. of Electroscience, Lund University
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Highlights
A scenario of future radio systems
Circuits handling multiple systems
Circuits for ultra low voltage
Circuits for MIMO system
Circuits of UWB system
Circuits for Future Radio Systems, CCCD Workshop 2004, September 2004
Jiren Yuan, Dept. of Electroscience, Lund University
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Wireless connectivity
0.2 0.5 10-50 100
Bandwidth (Mb/s)
WAN (2.5/3G)
GPRS, WCDMA, UMTS
LAN
802.11
PAN
Bluetooth, UWB
BAN
1000
Circuits for Future Radio Systems, CCCD Workshop 2004, September 2004
Satellite
1M 10M 100M 1-5km 500-1000km
Global
Internet
Jiren Yuan, Dept. of Electroscience, Lund University
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Handling of multiple systems
Infrastructure has to be set up for individual systems due
to different area coverage. Low cost is important.
As an example, New York city decides to cover the whole city with
WLAN network. A large amount of WLAN posts will be placed.
At the user side, a low complexity low power single flexible
device for multiple systems (GPRS, WCDMA, 802.11a,
802.11b, Bluetooth, UWB, etc.) would be attractive.
Software radio may be an ultimate solution, but hardware
flexibility is still necessary in order to reduce power
consumption.
Circuits for Future Radio Systems, CCCD Workshop 2004, September 2004
Jiren Yuan, Dept. of Electroscience, Lund University
4

Handling of variable data rate
Flexible Device
Circuits for Future Radio Systems, CCCD Workshop 2004, September 2004
High-End
Video
Video
Audio
Sensors
Gbit/s
Mbit/s
bit/s
Jiren Yuan, Dept. of Electroscience, Lund University
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Flexible radio
One of the currently running projects
Adaptive
Interface
Analog/RF &
Flexible
Radio
Fronten
d
Flexible
ADC
Multiple
Antennas
Mixed Signal Digital Baseband
Design for System-on-Chip (SoC)
Circuits for Future Radio Systems, CCCD Workshop 2004, September 2004
Design Space Exploration
Flexible
OFDM
Flexible
Coding
Decoding
Co-funded by Socware and 3 EU projects.
Flexible
Multimedia
Processing
Jiren Yuan, Dept. of Electroscience, Lund University
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Antenna issues
Wide Band Antenna
bulky and inefficient
Narrow Band Antenna
small and efficient
Advantages of using adaptive interface:
Narrow band antenna offers additional filtering.
Adaptive impedance matching for varying frequency and
surrounding.
An open question:
For a duplexer distance of 190 MHz required by WCDMA, special
technique is needed.
Circuits for Future Radio Systems, CCCD Workshop 2004, September 2004
Chip
Adaptive
Interface
Multi-System
Transceiver
Multi-System
Transceiver
Jiren Yuan, Dept. of Electroscience, Lund University
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Transceiver and flexibility
Dual-Band Receiver (802.11a and 802.11b)
- 0.18 µm CMOS
- Capacitive tuning (2.4/5GHz)
- VCO integrated
Fully Integrated CMOS Transmitter (Bluetooth)
- 0.18 µm CMOS
- Without off-chip filters, high integration
- High efficiency over the entire frequency range
- VCO integrated
Circuits for Future Radio Systems, CCCD Workshop 2004, September 2004
Jiren Yuan, Dept. of Electroscience, Lund University
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Flexible ADC
Pipelined ADC has a potential flexibility
Reconfigurable architecture is possible (pipeline ↔ cyclic)
Power-down for unused cells
A two-stage cyclic cell:
Phase 1:
Phase 2:
Mx2 S
S
Mx2
Circuits for Future Radio Systems, CCCD Workshop 2004, September 2004
A Flexible Pipelined ADC
6-12 bit, 16-80 MS/s, 26-82mW
Jiren Yuan, Dept. of Electroscience, Lund University
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Low voltage/power issue
Voltage (V)
2.0
1.5
1.0
0.5
0.0
‘99
‘01
‘04
180 130 90 65 45 32 22
Minimum transistor channel length (nm)
Circuits for Future Radio Systems, CCCD Workshop 2004, September 2004
‘07
‘10
‘13
Low voltage issue has to be taken into account
More critical for transmitter than receiver
From ITRS
V DD
V T
‘16
Jiren Yuan, Dept. of Electroscience, Lund University
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1V Bluetooth front-end
Circuits for Future Radio Systems, CCCD Workshop 2004, September 2004
LNA + Mixer
(High linearity by bootstrapping)
LNA + Q-Mixer + Q-VCO
(< 1° quadrature phase error)
0.25 µm CMOS, VT≈0.5V, a signifiant progress.
Circuit technique must continuously handle even lower voltage.
Jiren Yuan, Dept. of Electroscience, Lund University
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Flexible OFDM for WLAN
D/A
Cyclic
Perfix
• Flexible mapper to handle different modulation schemes
Pipelined 32-1024 points flexible IFFT/FFT processor
Variable choice of cyclic prefix (CP)
Low power by turned off unused parts
Compatible with physical layers of Hiperlan2 and 802.11a
Circuits for Future Radio Systems, CCCD Workshop 2004, September 2004
IFFT Mapper
Digital Baseband
OFDM Transmitter
Flexible
Coder
Jiren Yuan, Dept. of Electroscience, Lund University
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DAC for flexible transmitter
A quadrature Direct Digital Modulator
I
Interpolation DAC without filter
Q
DAC
DAC
LO
PA
90°
PA
DAC:
0.35 mm digital CMOS
3-100MHz, 10-bit
16x linear interpolation
SFDR = 63.4 dB
3.3V, 45mW
Circuits for Future Radio Systems, CCCD Workshop 2004, September 2004
Low image (- 50-60 dBc)
Low-stack current modulated PA
Quadrature DDM achieved
Flexibility in modulation
Modulator + PA:
16QAM, 3.75Mb/s,
-50dB image
GSM, -61dB umage
1 GHz carrier
3.3V, 140mW
Jiren Yuan, Dept. of Electroscience, Lund University
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Flexible coding and decoding
Flexible Encoder
Options of recursive/nonrecursive convolutional codes
Flexible rate b/c, b=1..15, c=2..16, b

Circuits for multiple antennas incl. MIMO
Data
S/P
Tx
Tx
Tx
Tx
Low complexity
transmitter
Rx
Rx
Rx
Rx
PE
Circuits for Future Radio Systems, CCCD Workshop 2004, September 2004
QR-factorisation
r = Hs + n
Channel
Estimation
PE PE PE
PE
PE PE
PE
High complexity
receiver
PE
H ^
PE
PE
PE
Symbol
Detection
H-1 ^
Matrix
Inversion
PE
PE
PE
PE PE PE PE
s = H-1 ^ ^
r
Inversion of
triangular submatrix
PE
Jiren Yuan, Dept. of Electroscience, Lund University
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Matrix inversion circuit
Aiming for low complexity and flexibility.
PE
PE PE PE
PE
PE PE
PE
QR-factorisation
PE
PE
Triangular matrix
architecture
Mapping
Circuits for Future Radio Systems, CCCD Workshop 2004, September 2004
Area reduction:
O(N2 /2) to O(N) PEs
Scalable: flexibility
PE PE PE PE
Linear array
architecture
CORDIC based
Low complexity
Numerically stable
PE
Mapping
Single
processing
element
Jiren Yuan, Dept. of Electroscience, Lund University
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UWB radio system
Carrier frequencies:
Imaging system, < 3.1 GHz, > 10.6 GHz
Communication, sensor net, 3.1 – 10.6 GHz
Vehicular radar systems, 24 – 29 GHz
Bandwidth
Computer connections, a few MHz
High speed internet, > 50 MHz
Indoor geo-location, 0.1 – 7.5 GHz
Circuits for Future Radio Systems, CCCD Workshop 2004, September 2004
Jiren Yuan, Dept. of Electroscience, Lund University
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Impulse radio system
Pulse Position Modulation (PPM – one of the modulation methods)
T p=T f /100
T f
Requirements on the transmitter and the receiver
No need of filters
Need of broadband antennas
High data rate
Accurate timing (low jitter)
Highly accurate channel estimation and equalization
Circuits for Future Radio Systems, CCCD Workshop 2004, September 2004
Jiren Yuan, Dept. of Electroscience, Lund University
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Circuits for ultra high carrier systems
WLAN, UWB, Short-Range Radar, Radio Imaging, ……
For wider bandwidth, carrier has to be higher
Available frequencies are higher and higher
Small antenna for portable use
A running RF front-end project (VINNOVA)
Target: 60GHz CMOS WLAN in 2010
First step: 10GHz in 2004
Process: IBM 90nm through EBT
Include also transmitter
Circuits for Future Radio Systems, CCCD Workshop 2004, September 2004
Jiren Yuan, Dept. of Electroscience, Lund University
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Thank you for your
Circuits for Future Radio Systems, CCCD Workshop 2004, September 2004
attention!
Jiren Yuan, Dept. of Electroscience, Lund University
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