FHSS (Fast Frequency Hopping )..........

Fast Frequency Hopping

1. Presented By:
Pramod Metri
Frequency Hopping Enables
Quick Frequency Shifting at
100ns
Date :-24/10/2024

2. Contents
Introduction
Block Diagram of FHSS
Types of FHSS
Fast Frequency Hopping Spread Spectrum (FHSS)
Theoretical Calculations for Fast FHSS
Problem Statement (from PARAS)
Applications

3. Introduction
FrequencyHoppingSpreadSpectrum(FHSS)isamethodoftransmittingradiosignalsby
rapidlyswitchingacarrieramongmanyfrequencychannels,usingapseudorandom
sequenceknowntobothtransmitterandreceiver.
Thedatasignalismodulatedwithanarrowbandcarriersignalthat"hops"inarandombut
predictablesequencefromfrequencytofrequencyasafunctionoftimeoverawidebandof
frequencies.
Itisusedasamultipleaccessmethodinthefrequency-hoppingcodedivisionmultipleaccess
(FH-CDMA)scheme.
Apseudo-noisecodeorPNgeneratorprovidesatableoffrequenciesandalsoindexesit.
EachoftheKbitsmakesparticularmentionofthe2Kfrequencies.

4. Block Diagram of FHSS

5. Types of HFSS
There are two types of frequency hopping:
1.Slow Frequency Hopping Spread Spectrum
2.Fast Frequency Hopping Spread Spectrum

6. Fast Frequency Hopping Spread Spectrum (FHSS)
FHSSisatechniqueusedinwirelesscommunicationwherethecarrierfrequencyrapidlyhops
amongmanyfrequencychannelsduringtransmission.Thismethodimprovesresistanceto
interferenceandeavesdropping,enhancessignalsecurity,andallowsforbetteruseofthe
availablespectrum.
Keyfeaturesinclude:
•Speed:Thefrequencychangesquickly,oftenmultipletimespersecond,whichhelpsin
avoidinginterferenceandjamming.

7. Fast Frequency Hopping Spread Spectrum (FHSS)
•Robustness:Byspreadingthesignaloverawiderangeoffrequencies,FHSSisless
susceptibletonarrowbandinterference.
•Security:Rapidlychangingfrequenciesmakeitdifficultforunauthorizedlistenerstointercept
thesignal.

8. Theoretical Calculations for Fast FHSS
CalculatingparametersforFastFrequencyHoppingSpreadSpectrum(FHSS)
involvesseveralkeymetrics,includinghoprate,bandwidth,andprocessinggain.Here’s
abriefoverviewofsomeimportantcalculations:
1.Hop Rate (H):
The hop rate is the number of frequency hops per second. It can be calculated
as:
H=
??????
??????
Where:
N= number of frequency channels
T = time duration of each hop (in seconds)

9. Theoretical Calculations for Fast FHSS
2. Bandwidth (B)
The total bandwidth required for an FHSS system can be estimated using the
following formula:
B=N⋅Δf
Where:
N = number of channels
Δf = bandwidth of each channel (the spacing between hops)

10. Theoretical Calculations for Fast FHSS
3 Processing Gain (PG)
Processinggainisameasureofhowmuchthesignalisspread,whichhelpsin
improvingthesignal-to-noiseratio(SNR).Itcanbecalculatedas:
PG=10⋅log
10(B/R
b)
Where:
B = total bandwidth used
R
b​ = bit rate of the transmitted data

11. Theoretical Calculations for Fast FHSS
4 Time Bandwidth Product (TBP)
Thetime-bandwidthproductisanimportantparameterthatdefinesthespreadof
thesignal:
TBP=B⋅T
Where, T is the duration of the signal.

12. Problem Statement
Frequency Hopping Enables, Fast Frequency Shifting at 100ns

13. APPLICATION

14. Key Applications of FHSS
•BluetoothTechnology:BluetoothusesFHSStotransmitdataovershortdistances,allowing
devicestocommunicatewirelesslywhileminimizinginterferenceandenhancingsecurity.
•MilitaryCommunications:FHSSisemployedinmilitaryradiosystemstoprovidesecure
communicationchannels.Therapidfrequencychangesmakeitchallengingforadversariesto
interceptorjamthesignals.
•WirelessSensorNetworks:FHSSisusedinsensornetworkstoensurereliabledata
transmissioninenvironmentswithpotentialinterference,suchasindustrialsettings.
•RemoteControls:Manyremotecontroldevicesfortoys,drones,andotherequipmentuse
FHSStoavoidinterferencefromotherdevicesoperatingonsimilarfrequencies.

15. Key Applications of FHSS
•AmateurRadio:SomeamateurradiooperatorsutilizeFHSStechniquesfordigital
communicationstoimprovesignalclarityandreducetheriskofinterception.
•HealthMonitoringSystems:Inmedicalapplications,FHSScanbeusedforwirelesspatient
monitoringsystemstotransmitvitalsignssecurelyandreliably.
•SatelliteCommunications:CertainsatellitecommunicationsystemsuseFHSStominimize
theeffectsofmultipathfadingandimprovesignalintegrity.

16. THANK YOU