Secure, Low-Power IoT Communication Using Edge-Coded Signaling

162 Pages·2022·5.635 MB·English

by  Shahzad Muzaffar, Ibrahim (Abe) M. Elfadel

Shahzad Muzaffar
Ibrahim (Abe) M. Elfadel
Secure,
Low-Power IoT
Communication
Using Edge-Coded
Signaling
Secure, Low-Power IoT Communication Using
Edge-Coded Signaling
Shahzad Muzaffar • Ibrahim (Abe) M. Elfadel
Secure, Low-Power IoT
Communication Using
Edge-Coded Signaling
ShahzadMuzaffar Ibrahim(Abe)M.Elfadel
KhalifaUniversity KhalifaUniversity
AbuDhabi,UnitedArabEmirates AbuDhabi,UnitedArabEmirates
ISBN978-3-030-95913-5 ISBN978-3-030-95914-2 (eBook)
https://doi.org/10.1007/978-3-030-95914-2
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Tomyparents(Shamshad andMuzaffar),
belovedwife(Umber),
son(Anzar)andsisters(Shumaila, Shaista,
andSumaira)
Shahzad
Totheblessedmemoryofmybrother
ZaherElfadel
1965–2010
Abe
Prologue
Yourassumptionsareyourwindowsontheworld.
Scrubthemoffeveryonceinawhile,orthelight
won’tcomein.
IsaacAsimov
The accepted IoT wisdom is that it is much more energy-efficient to compute on
the edge than to communicate with the hub. Yet, this accepted wisdom is based
on the premise that the power hog that lives in the communication subsystem of
the IoT node must be avoided at all costs and that whatever power that is still
availableshouldbeusedtomaketheIoTnodesmart.TheTinyMLframeworkfor
machinelearningontinymicro-controllersisbasedonsuchpremiseandepitomizes
thecurrentwisdomundertheedge-computingparadigm.
The ultimate aim of this research monograph is to revisit this premise by
giving a concrete example of a novel, ultra-low-power, robust, and secure, IoT
communication protocol that is meant to enable innovative IoT architectures that
canbridgethechasmbetweenedgeandcloudcomputing.
Theresearchdescribedhereinisasummaryofseveralyearsofinvestigationinto
asinglewhat-if questionwithregardstothedesignofsignalingprotocols,namely,
whatif theIoTcommunicationsubsystemcanoperatereliablyandsecurelywithout
thecircuitrydedicatedtoclockanddatarecovery(CDR).
The main motivation of asking this what-if question is the basic observation
that a CDR circuit is a significant contributor to power consumption in the
communicationtransceiver.Beingabletosaveasmuchofitspoweraspossiblein
anIoTnodeisboundtoimpactthedebateoncomputationvs.communicationand
onedgevs.cloudintelligence.Intermsofrealestate,transceiverswithCDRcircuits
havetensofthousandsofgates,andthereforeasignificantsavingofsiliconareawill
beachievedincasetheCDRcircuitissimplifiedorevenpossiblyeliminated.
vii
viii Prologue
NotonlydowegiveanexistenceproofofsuchaCDR-lesscommunicationlink,
butalso,weprovideacompleteecosystemofhardwareandfirmwarebuiltaround
such a communication link. This ecosystem comprises an application-specific
processor, automatic protocol configuration, power and data rate management,
cryptographicprimitives,andautomaticfailurerecoverymodes.Theresultinglink
anditsassociatedecosystemarefullycompatiblewithIoTrequirementsonpower,
footprint,security,robustness,andreliability.
ThefundamentalideaoftheproposedIoTcommunicationprotocolistoencode
the ON bit in the data word as a sequence of pulses whose count is based on the
ON-bitindex.Atthereceiver,thisindexisdecodedbysimplycountingthenumber
of rising edges in the pulse sequence. This is the main reason we have called this
protocolEdge-CodedSignalingorECS.
Fromthisbasicidea,ECShasevolvedthroughthreedifferentgenerations,ECS1,
ECS2, and ECS3, into a full family of protocols. They are all variations on the
fundamentalthemeofpulsegenerationfortheONbitsatthetransmitterendofthe
linkandedgecountingatthereceiverend.Theyarealldescribedinthismonograph
alongwithhardwareprototypesthatallowustothoroughlybenchmarkandprecisely
quantify the IoT advantages of this novel family of signaling protocols. These
advantagescanbesummarizedasfollows:
1. ECS results in a major simplification of the IoT device transceiver. This
simplification in turn contributes to major gains in footprint, power savings,
andcost.
2. ECS supports dynamic data rates, and the ECS parameters can be readily
optimizedtoachievethemaximumaveragedatarateforagivenapplication.
3. ECSisrobustinthatittoleratessignificantdevice-to-devicevariationsinclock
frequencyasmaybeexpectedinaheterogeneous,asynchronousIoTnetwork.
4. Along with a low-power design point due to transceiver simplification, ECS
provides additional opportunities for power saving, both at the physical layer
levelandatthepulsedesignlevel,thatarestraightforwardtoimplement.
5. ECS supports network protocols for automatic ECS parameter settings across
a setof networked IoT devices. These automatic ECS configuration protocols
areuniversalinthattheycanbeappliedforanynetworktopology.
6. The ECS family of protocols is amenable to compact programming using
a domain-specific, RISC-like, ECS processor. Its instruction set architecture
achievesmorethananorderofmagnitudeofreductioninembeddedcodesize
andprovidesIoTdesignerswiththeflexibilitytoprogramnewECSprotocols
thatareadaptedtospecificIoTcommunicationtasks.
7. ECS supports low-overhead doubling of data rates using double-edge-coded
signalingwhereboththerisingandfallingedgeofthepulseareusedtoencode
theONbitsinthebitstream.
8. ECS enables a close synergy between encoding and encryption, and provides
a unique opportunity for significantly strengthening light-weight encryption
algorithms in a way that is not possible with traditional signal encoding
methods.
Prologue ix
9. ECS development is supported with various tools for embedded C program-
ming, debugging, and system integration. These tools greatly facilitate the
deploymentofhardwareplatformsforIoTsensornetworks.
10. TherobustnessandreliabilitypropertiesofECSmakeitthesignalingtechnique
ofchoiceinchallengingmediasuchasbody-coupledcommunication.
The above 10 advantages are aligned with the 10 chapters of this monograph.
Byandlarge,eachchapterisorganizedtoleadfromtheIoTcommunicationdesign
problem to its solution under the ECS paradigm along with supporting hardware
validationusingeitheranFPGAoranembeddeddesignplatform.ASICsynthesis
results using GLOBAFOUNDRIES 65nm technology node have also been used
throughout the chapters to further support the hardware results of the FPGA and
embeddeddesignplatforms.OurowndesignoftheECSprotocoltargetedthesweet
spotofasingle-channelIoTcommunicationlinkwithadatarateintherangefrom
4.2to26.7Mbpsandwithapowerconsumptioncapof20µW.
Althoughsignificantworkhasalreadybeeninvestedindeveloping,testing,and
validatingECSanditsecosystem,therearestillseveralopenresearchproblemsthat
are important to tackle in the next phase of ECS development. We have alluded
to many of these problems at appropriate sections within the book chapters. In an
epiloguetothisbook,wehaveconsolidatedandsummarizedalltheseopenresearch
problems with the hope that they will be of interest to colleagues and graduate
studentsfromtheIoTresearchcommunity.
Many of the results described in this monograph have already appeared in our
prior conference and journal publications between 2015 and 2021. However, we
have made a determined effort to synthesize these results and present them in a
coherentnotationalandconceptualframeworksothatthemonographcanserveas
an accessible, self-contained reference, not just for IoT professionals but also for
graduate students who are entering the field and interested in pursuing research in
theareaofsecure,low-powerIoTcommunication.
AbuDhabi,UnitedArabEmirates ShahzadMuzaffar
AbuDhabi,UnitedArabEmirates Ibrahim(Abe)M.Elfadel
November2021
Acknowledgements
This research monograph is based on the PhD thesis of the first author conducted
under the supervision of the second author at the Advanced Digital Systems
Laboratory of the Masdar Institute, now part of Khalifa University, Abu Dhabi,
UAE.
Severalcolleagueshavecontributedtime,effort,andsupporttothisresearchover
theyears.WeparticularlythankDr.JeraldYoo(NationalUniversityofSingapore)
andDr.AymanShabra(MediaTek,USA)forhelpfuldiscussionsattheearlystages
of this project. We also thank Dr. Zeyar Aung (Khalifa University, UAE) and
Dr. Owais Waheed Talaat (Habib University, Pakistan) for their help with ECS
encryption, and Mr. Numan Saeed (Mohamed Bin Zayed University of Artificial
Intelligence, UAE) for his help with ECS automatic configuration. Special thanks
areduetoProf.NevilleHogan(MIT)andDr.MihaiSanduleanu(KhalifaUniversity,
UAE) for serving on the PhD Thesis Committee of the first author and providing
valuablefeedback.
TheauthorsgratefullyacknowledgethesupportprovidedbytheSemiconductor
ResearchCorporation(SRC),USA,undertheAbuDhabiSRCCenterofExcellence
on Energy-Efficient Electronic Systems (ACE4S), Contract 2013 HJ2440, with
customizedfundingfromtheMubadalaInvestmentCompany,AbuDhabi,UAE.
TheyalsothanktheOfficeofTechnologyManagementandInnovationatKhalifa
UniversityfortheirhelpinprosecutingUSPatents10,263,765and11,133,891.
xi
Contents
1 Introduction................................................................. 1
2 Edge-CodedSignalingTechniques........................................ 7
2.1 Edge-CodedSignaling(ECS)........................................ 8
2.1.1 Edge-CodingScheme ...................................... 8
2.1.2 ECSSegmentation.......................................... 9
2.1.3 ECSEncoding .............................................. 9
2.1.4 ECSTransmitter............................................ 11
2.1.5 ECSReceiver............................................... 13
2.1.6 ECSTransmissionSystem ................................. 15
2.1.7 ECSDataRate.............................................. 16
2.2 ECSOptimizations................................................... 18
2.2.1 OptimumInter-symbolSeparatorα ....................... 18
2.2.2 OptimumSegmentLengthl................................ 19
2.3 EarlierVersionsofECS.............................................. 20
2.3.1 DataRates................................................... 22
2.3.2 Optimizations............................................... 22
2.4 ExperimentalSetupsandResults.................................... 23
2.5 Analysis............................................................... 28
2.5.1 DataRate.................................................... 28
2.5.2 DataWordLengthandComplexity........................ 29
2.5.3 ErrorDetectionandCorrection............................ 31
2.5.4 BitErrorRate............................................... 32
2.5.5 PulseWidthandShape..................................... 33
2.5.6 Reliability................................................... 33
2.5.7 Robustness.................................................. 34
2.5.8 OverallLatency............................................. 35
2.5.9 Networking ................................................. 35
2.6 Conclusions........................................................... 36
xiii