Software Defined Modems for “The Internet of Things” Dr. John Haine, IP Operations Manager www.cognovo.com www.cognovo.com
Software Defined Modems for “The Internet of
Things”
Dr. John Haine, IP Operations Manager
www.cognovo.comwww.cognovo.com
What things?
� “20 billion connected devices”
� Manufactured for global markets
� Low cost
� Lifetimes from months to decades
� Different...
Networks
Frequencies
Protocols
� Evolving networks & spectrum allocations
� Versatility & programmability required
2
Multiple systems and bands
� Cellular
� GSM, HSPA, LTE(A),
EVDO, WiMax,...
� Short range
� WiFi, Zigbee, UWB,
� Conventional cellular
bands, 400 – 2600 MHz
� License-exempt – 2400 &
5800 MHz
� “Digital Dividend” � WiFi, Zigbee, UWB,
Bluetooth,...
� Emerging techniques
� “WhiteSpace”
� Other systems
� Tetra & derivatives
� “Digital Dividend”
spectrum
� “Shared” bands
3
Focus on the radio modem
“Apps”IP packets
4
Modem – HSPA, LTE etc
OS – Android etc.
“Photons”Radio
Digital
processing
I/Q stream
Relative computational load for LTE Video
decoder:
~500 MO/s
DSP
arithmetic:
~50 GO/s
5
LTE Modem
Baseband Complexity
200
250
300
350
400
450
500
Bitr
ate,
Mbp
s
LTE 50GOp/s
LTE-A 1Gbps 300GOp/s
60
...Arithmetic
6
0
50
100
150
1990 1995 2000 2005 2010 2015
GSM
GPRS 200MOp/s
HSPA 5GOp/s
HSPA+ 20GOp/s
0
10
20
30
40
50
60
1990 1995 2000 2005 2010 2015
Cum
ulat
ive,
Mod
ulat
ion
& C
odin
g S
chem
es
GSMGPRS
HSPA
HSPA+
LTE
LTE-A
WCDMA
Bit shuffling...
Conventional Modem Architecture
Applications
Protocol
Stack
Layer 1
7
Software
HardwareProtocol
Processor
System
RF
H/w Drivers
DSP
Dedicated
arithmetic
hardware
Conventional Modem Architecture
� Hardware is inflexible
� Different / upgraded / new protocols
� Multi-mode needs separate hardware engines – increases chip
area & cost
� Distributed memory less efficient, increases area / cost
� Difficult development process� Difficult development process
� FPGA prototyping cannot fully model final device
� Software development depends on chip availability
� Hardware bugs need software work-arounds which may not
be ideal
� Cost of large chip developments rising exponentially
� Need to amortise over maximum number of applications
8
Processor SystemApplication software
Product development – the software paradigm
My PC is a...
� Typewriter
� Calculator
� Phone
� TV receiver
� Music player
...often simultaneously!
Software development...
� Is well understood
� Allows continuous improvement
� “Infinite flexibility”
� A platform for unpredictable
products
9
Drivers
“Real-world” interfaces
Example - universal radio/TV receiver for the PC
http://www.crestatech.com/products/ctc200.html
10
http://www.crestatech.com/products/ctc200.html
http://www.mirics.com/
Software Defined Modem (a/k/a SDR)
Processor SystemApplication software
� Hardware architecture becomes standards – independent
� Simplify production logistics – single hardware platform for
multiple standards & standards combinations – the “world
modem”
� Update firmware in the field to fix problems and/or change air
interface
� Extend product lifetime11
Drivers
Multi-band radio module
Barriers to SDM
Computation load – Moore’s Law is not enough!
� As geometry gets smaller, voltage gets lower, clock speeds
static or decreasing
� Overall single processor Mips/MHz/mW stops improving
� Large processor systems have to become multi-core
Standards complexityStandards complexity
� Ever more complex modulation & coding schemes
� Wider RF bandwidth
� Need for legacy support
� Management of task scheduling within and amongst protocols
RF technology
� Wideband operation, multiple frequencies
� Time and frequency duplex modes
12
Lifting the barriers
Vectorisation
� Operate on large blocks of samples (vectors) (e.g. FFT)
� SIMD computing architectures apply same operation on multiple
data values in the same processor cycle - vector arithmetic
Multi-processing
� VLIW computing architectures allow multiple operations on � VLIW computing architectures allow multiple operations on
independent data in the same processor cycle
� Multiple processors on same die to increase MiPs/MHz/mW
� Novel hardware architectures to enable deterministic
performance
Programming
� Automatic compilers to support multiprocessing
� SDM OS to support task scheduling across multiple cores
� System tools for multiprocessing design, development and debug
13
Lifting the barriers
Integrated RF technologies
� New methods such as MEMs for RF switching
� Monolithic filtering technologies such as FBARs
� DPD / ET for efficient wideband power amplifiers
� Multi-mode & multi-band integrated radios
14
Software Defined Modem (SDM)
Design
Environment
Applications
System
SDK
System
integration &
Modem specific
operation
Protocol Plane Control Plane
Layers 2, 3, 4
Protocol
Stack
Layer 1
Data Plane
Physical
Layer
PHY Kernel PHY Kernel
15
PHY coding &
optimisation
SDK
Kernel
SDK
Software
Hardware
integration &
modelling
Generic s/w
execution
environment
Modem Compute Engine
Stack
SDM-OSPHY Kernel
Library
Layer 1
Processor
PHY
Processor
Protocol
Processor
System
RADIO
DigRF
Ideal M2M module architecture
� Flexible broadband RF
� Software defined modem
� All signal processing in programmable
processor
� Air interface defined by software
download, at any stage in product life-
cycle
Modem
Microcontroller
system
Interfaces
cycle
yields...
� One hardware platform for all standards
� Upgrade / change air interface during
end-product manufacture or after sale
16
RF transceiver
DSP
Standardisation & regulatory barriers to SDM
� Mode incompatibility
� Device may need to be multiple-network aware
� Protocols need to permit “listening” for “foreign” air-
interfaces – difficult for “legacy” modes
� Approvals
� Approvals given for defined hardware platform and software � Approvals given for defined hardware platform and software
version – SW version may change frequently as bugfixes &
improvements are made
� Tests may need to recognise operation in “foreign” modes
� Separate approval regimes may apply to modes in the same
device
17
SDM as an enabler for the “Internet of Things”
� Advances in silicon integration & computer
architectures now allow advanced radio modems to be
implemented in software (the “software defined
radio”)
� RF technology allows multi-band / multimode
operationoperation
� Future products will be able to have a single radio
platform to provide radio connectivity across many
diverse networks and bands - massive scale economies
can result
� Standards and approvals regimes need to adapt to the
new possibilities that SDM creates
18