This is mimo of radio frequency of wireless communication

1. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
Overview: Trends and
Implementation Challenges for
Multi-Band/Wideband
Communication
Mona Mostafa Hella
Assistant Professor, ESCE Department
Rensselaer Polytechnic Institute

2. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
•Any integrated circuit used in the frequency range: 100 MHz to 3
GHz (till 6GHz can sometimes be considered RF). Currently we are
having mm-wave circuits in Silicon (17GHz, 24GHz, 60GHZ, and
77GHz)
•Generally RFIC’s contain the analog front end of a radio
transceiver, or some part of it.
•RFIC’s can be the simplest switch, up to the whole front end of a
radio transceiver.
•RFIC’s are fabricated in a number of technologies: Si Bipolar, Si
CMOS, GaAs HBT, GaAs MESFET/HEMT, and SiGe HBT are today’s
leading technologies.
We are going to design in either CMOS, or SiGe.
What is RFIC?

3. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
RF Transmitter RF Receiver
Basic Wireless Transceivers

4. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
The last 10 years in wireless systems

5. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
Where we are in terms of technology?
The metric for performance depends on the class of circuit. It can
include dynamic range, signal-to-noise, bandwidth, data rate, and/or
inverse power.
*Source: International roadmap for semiconductors ITRS 2005
Application-specific wireless node implemented
in a low cost technology (CMOS) can provide
programmability, low cost and low power
solution

6. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
The next 10 years !!

7. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
Spectrum Utilization

8. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
 A Cognitive Radio (CR) can be defined as “a radio that
senses and is aware of its operational environment and
can dynamically adapt to utilize radio resources in time,
frequency and space domains on a real time basis,
accordingly to maintain connectivity with its peers while
not interfering with licensed and other CRs”.
 Cognitive radio can be designed as an enhancement
layer on top of the Software Defined Radio (SDR)
concept.
Introduction to Cognitive Radio

9. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
 Basic Non-Cognitive Radio
Architecture:
 Cognitive Radio architecture:
Networked Device
Antenna
Coupling
Data
Modem
Processor
Transmitter
and
Receiver
Wireless Data Transceiver Subsystem Module
Spectrum Scanning and Interference Avoidance Module
Data Modem
Processor
Networked Device
Scanning
Engine
Spectrum
Analysis
Engine
Channel
Pooling
Server
Transmitter
and Receiver
Antenna
Sharing
Module
Data Modem
Processor
Transmitter
and Receiver
Introduction to Cognitive Radio-2

10. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
Window of Opportunity
Time (min)
Frequency
(Hz)
 Existing spectrum policy forces
spectrum to behave like a fragmented
disk
 Bandwidth is expensive and good
frequencies are taken
 Unlicensed bands – biggest
innovations in spectrum efficiency
 Recent measurements by the
FCC in the US show 70% of the
allocated spectrum is not utilized
 Time scale of the spectrum
occupancy varies from msecs to
hours

11. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
CR Definitions

12. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
 Today “spectrum“ is regulated by governmental agencies, e.g. FCC)
 “Spectrum“ is assigned to users or licensed to them on a long term basis
normally for huge regions like whole countries
 Doing so, resources are wasted
 Vision: Resources are assigned where and as long as they are needed,
spectrum access is organized by the network (i.e. by the end users)
 A CR is an autonomous unit in a communications environment. In order
to use the spectral resource most efficiently, it has to
- be aware of its location
- be interference sensitive
- comply with some communications etiquette
- be fair against other users
- keep its owner informed
 CR should
 Sense the spectral environment over a wide bandwidth
 detect presence/absence of primary users
 Transmit in a primary user band only if detected as unused
 Adapt power levels and transmission bandwidths to avoid interference to
any primary user

13. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
Software Radio (SR): An ideal SR directly samples the antenna output.
1) According to
J. Mitola, 2000
Digital Radio (DR): The baseband signal processing is invariably implemented on a DSP.
Software Defined Radio (SDR): An SDR is a presently realizable version of an SR:
Signals are sampled after a suitable band selection filter.
Cognitive Radio (CR): A CR combines an SR with a PDA
trans
mit
receive
radio frontend
radio
frequency
RF
baseband
processing
t
o
u
s
er
from
us
er
analog-to-digital
conversion
A/D
data
processing
control
(parametrization)
CR Definitions

14. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
D/A
D/A
PA
PA
PA
LNA A/D
IFFT
FFT
ADAPTIVE
LOADING
INTERFERENCE
MEAS/CANCEL
MAE/
POWER CTRL
CHANNEL
SEL/EST
TIME, FREQ,
SPACE SEL
LEARN
ENVIRONMENT
QoS vs.
RATE
FEEDBACK
TO CRs
IFFT
IFFT
FFT
FFT
ADAPTIVE
LOADING
ADAPTIVE
LOADING
INTERFERENCE
MEAS/CANCEL
INTERFERENCE
MEAS/CANCEL
MAE/
POWER CTRL
CHANNEL
SEL/EST
TIME, FREQ,
SPACE SEL
TIME, FREQ,
SPACE SEL
LEARN
ENVIRONMENT
LEARN
ENVIRONMENT
QoS vs.
RATE
QoS vs.
RATE
FEEDBACK
TO CRs
FEEDBACK
TO CRs
 Sensing Radio
• Wideband Antenna, PA
and LNA
• High speed A/D & D/A,
moderate resolution
• Simultaneous Tx & Rx
• Scalable for MIMO
 Physical Layer
• OFDM transmission
• Spectrum monitoring
• Dynamic frequency
selection, modulation,
power control
• Analog impairments
compensation
 MAC Layer
• Optimize transmission
parameters
• Adapt rates through
feedback
• Negotiate or
opportunistically use
resources
RF/Analog Front-end Digital Baseband MAC Layer
Cognitive radio Functions

15. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
RF Front-End Schematic
Digital
Processor
A/D
D/A
Baseband
amplifiers
and filters
Up & down
frequency
converters
RF
filters
Digital
Mixed
Front-End:
Analog/RF
Waveguide
filters
Low-noise
amplifier
LO
Low-noise
amplifier
LO
Power
amplifier
LO
Local
oscillators
Power
amplifier
LO
Local
oscillators
Analog &
Digital
Converters

16. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
amplifier
Wideband
down-
converter
filter
Wideband
or
multiband
antenna
Agile
LO
Wideband
power
amplifier
Wideband
up-converter
filter
Wideband
LNA
amplifier
Program-
mable
Filter
Program-
mable
Filter
Agile
LO
s
w
i
t
c
h
End User
Equipment
Digital
Processor
A/D
D/A
•Baseband switch
•Crypto
•Modem
RF Front-End Challenges

17. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
Motivation
 Intelligence and military application require an application-
specific low cost, secure wireless systems.
 An adaptive spectrum-agile MIMO-based wireless node
will require application-specific wireless system:
 Reconfigurable Radio (operating frequency
band, bit rate, transmission power level, etc)
 Wide frequency coverage and agility
 Work independent of commercial infrastructure
 Large instantaneous bandwidth

18. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
 A/D converter:
– High resolution
– Speed depends on the application
– Low power ~ 100mWs
 RF front-end:
– Wideband antenna and filters
– Linear in large dynamic range
– Good sensitivity
 Interference temperature:
– Protection threshold for licensees
– FCC: 2400-2483.5 MHz band is
empty if:
 Need to determine length of
measurements
0 0.5 1 1.5 2 2.5
x 10
9
-90
-85
-80
-75
-70
-65
-60
-55
-50
-45
-40
Frequency (Hz)
Signal
Strength
(dB)
TV bands
Cell
PCS
0 0.5 1 1.5 2 2.5
x 10
9
-90
-85
-80
-75
-70
-65
-60
-55
-50
-45
-40
0 0.5 1 1.5 2 2.5
x 10
9
-90
-85
-80
-75
-70
-65
-60
-55
-50
-45
-40
Frequency (Hz)
Signal
Strength
(dB)
TV bands
Cell
PCS
Frequency (Hz)
Signal
Strength
(dB)
TV bands
Cell
PCS
System Challenges

19. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
Receiver
• Wideband sensing
• Different primary user signal powers and types
• Channel uncertainty between CR and primary user
Transmitter
• Wideband transmission
• Adaptation
• Interference with primary user
System Challenges

20. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
 High power consumption due to
simultaneous requirement of
high linearity in RF front-end
and low noise operation
 The conflicting requirements
occur since the linearity of the
RF front-end is exercised by a
strong interferer while trying to
detect a weak signal
 The worst case scenario is a rare event.
 A dynamic transceiver can schedule gain/power of the
front-end for optimal performance
Dynamic Operation: Near-Far Problem

21. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
 Cognitive radios are expected to be powerful tools for
mitigating and solving general and selective spectrum
access issues (e.g. finding an open frequency band and
effectively utilizing it).
 Improves current spectrum utilization (Fill in unused
spectrum and move away from occupied spectrum ).
 Improves wireless data network performance through
increased user throughput and system reliability.
 More adaptability and less coordination required
between wireless networks.
Advantages of CR

22. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
UWB Systems

23. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
Basics of UWB Signaling

24. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
Definition of UWB Systems

25. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
Why UWB?

26. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
UWB Applications

27. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
UWB Sensors

28. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
UWB Sensor Architectures

29. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
UWB receiver Architecture

30. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
UWB receiver Architecture

31. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
Multi-band OFDM UWB Architecture

32. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
Multi-band OFDM UWB Radio Architecture

33. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
Comparison of MB-OFDM radios

34. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
UWB Components/Subsystems

35. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
UWB Levels of Integration

36. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
UWB Basic Building Blocks (Pulse Generator)

37. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
Challenges in UWB IC Design

38. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
Challenges in UWB IC Design

39. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
Future Trends

40. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
Future Trends; UWB Beam forming

41. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
Multi-band VCO
 Existing Multiband VCOs/Frequency References are based
on:
 Switched inductor and/or capacitor LC tanks (Extra parasitics
and resistive loss  degrade both tuning range and phase
noise)
 Frequency dividers (higher phase noise and power
consumption)
 MEMS resonators (non-standard process, extra processing
steps, higher fabrication cost)
1/2
5.4-7.0GHz
1.72-2.25GHz 2.7-3.5 GHz
0.86-1.12GHz
1/4
1.35-1.7GHz
0.43-0.56GHz
5.4-7.0GHz
1.72-2.25GHz
M
U
X

42. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
Multi-Band VCO--Schematic
 Low-Band and High Band
Switching between bands:
Enable/Disable a buffer
In-Band Tuning:
“Primary” and “secondary” varactors

43. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
• Wireless Control of machines and
devices in the process and
automation industry
• Logistic Radio Frequency
Identification (RFID), includes
transportation, terminals, and
warehouses.
• Smart home appliance, remote
controls
• Medical monitoring health
conditions (wireless body area
network WBAN)
• Environmental monitoring, such
as smart dust or other ambient
intelligence
Future Trends
RF
RF-
-Powered Wireless Communication
Powered Wireless Communication
Circuits for Bio
Circuits for Bio
-
-Implantable
Implantable
Microsystems
Microsystems
Bio-sensor
RF
Communication
Circuit
DC
Gener-
ation
RF
RF-
-Powered Wireless Communication
Powered Wireless Communication
Circuits for Bio
Circuits for Bio
-
-Implantable
Implantable
Microsystems
Microsystems
Bio-sensor
RF
Communication
Circuit
DC
Gener-
ation

44. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
3D RF System Integration
Si-substrate SiGe/CMOS Chip
BCB Glass Substrate
Al
One Possible
Antenna
Implementation
Integrated Antenna
High Q inductors (top glass layer or inter-wafer
inductors
Digitally assisted RF/Analog Design (All blocks
can be optimized through vertical control signals)
Power Amplifier linearization Digital pre-
distortion or dynamic bias through bottom layer
monolithic DC-DC Converter
Added functionality/versatility
LNA
PA
LPF
IF
ADC
LPF DAC
IF
Baseband
DSP
OSC.
DC-DC
Converter
PA output matching
LNA input matching
Antenna

45. April 20th, 2007
Rensselaer Radio Frequency Integrated Circuits Lab.
3D Micro-Power Portable/Implantable RF Wireless
Systems for Biomedical Applications.
LNA
PA
LPF IF ADC
DAC
IF
OSC.
Antenna
RF
Transceiver
Passive
layer
Digital
processing
DC-DC Converter and
power distribution
Processor/
power
distribution
layer
Communications
Sensing
Control
EEG
HEARING
VISION
GLUCOSE
BLOOD
PRESSURE
TOXINS
IMPLANTS
DNA
PROTEIN
POSITIONING
WLAN
CELLULAR
UWB
NETWORK
LPF
(a) (b)
Wireless Body Area Network
(WBAN)