Transcript
8/8/2019 UWB Presentation
1/17
An IntroductionAn Introduction toto
Impulse Radio UltraImpulse Radio Ultra--Wide BandWide Band(IR(IR--UWB)UWB)
Presenter Tamim Arabi
Supervisor Dr. Zhizhang (David) Chen
Part of M.A.Sc Thesis Program Requirements at Dalhousie University
8/8/2019 UWB Presentation
2/17
OutlineOutline
y Definitions
y IR UWB pulses
y
Advantagesy Challenges
y Synchronization
y
Future work
8/8/2019 UWB Presentation
3/17
IntroductionIntroduction
yy UWBUWB is a wireless communication technologyfor transmitting digital data at high rates over awide spectrum of frequencies using very low
power levels.
y This makes it a good candidate technique forshort range indoor communication.
8/8/2019 UWB Presentation
4/17
DefinitionDefinition
y FCC:
UWB signals fractional bandwidth (Bf) > 20%
Or: more than 500 MHz of absolute bandwidth
FCCs ( First Note And Order 2002 )
8/8/2019 UWB Presentation
5/17
IRIR--UWB PulsesUWB Pulses
Carrier-less, short-duration pulses (ns~ps)with a very low duty cycle (< 0.5%)
E.g. A Gaussian monocycle.
8/8/2019 UWB Presentation
6/17
NarrowbandNarrowband vsvs UWBUWB
Narrowband Bf< 1%Wideband 1% < Bf< 20%
Ultra-Wideband Bf> 20%
8/8/2019 UWB Presentation
7/17
AdvantagesAdvantages
y Sharing the RF spectrum
Max of 41.3 dBm/MHz 75 nanowatts/MHz
y Large Channel Capacity {C=B log2 (1 + SNR)}
Low SNR
y Low transmit power
y Resistance to Jamming
y High Performance in Multipath Channels
y Simple transceiver architecture
8/8/2019 UWB Presentation
8/17
ChallengesChallenges
y Pulse-Shape Distortion
y Channel Estimation
y
Multiple-User Interferencey High-Frequency Synchronization
Sync must be achieved accurately.
Timing errors in the order ofnano seconds
can severely degrade system performance.
Different sync methods leads to differentreceivers: Coherent and Non-coherent.
8/8/2019 UWB Presentation
9/17
SynchronizationSynchronization
y Rake Receiver
The first proposal for coherent receivers.
Assigns number offingers to each multipath
component.
Very high number of fingers = very high powerconsumption, not acceptable.
8/8/2019 UWB Presentation
10/17
Synchronization..Synchronization..
y Transmitted Reference (TR) UWB
Bypasses the channel estimation.
In TR, a ref pulse is sent prior to each data
pulse.
Drawback: wastes transmission power andreduces transmission rate.
8/8/2019 UWB Presentation
11/17
Synchronization..Synchronization..
y Frequency-Shifted Reference (FSR) UWB
Avoided the delay element in the TR Receiver.
Drawbacks: Performance is affected by
frequency, phase, and amplitude offsets.
8/8/2019 UWB Presentation
12/17
Synchronization..Synchronization..
y Coded-Shifted Reference (CSR) UWB
Does not require any delay element (TR),separation is being done using digital codes
instead of analog carriers (FSR).
8/8/2019 UWB Presentation
13/17
Synchronization..Synchronization..
y Differential-CSR (DCSR) UWB
Data pulses are differentially encoded
Each data pulse sequence can be used as a ref
sequence of the next.
8/8/2019 UWB Presentation
14/17
Synchronization..Synchronization..yy FrameTimingFrameTiming: start of individual frames with
respect to receivers clock.
yy SymbolTimingSymbolTiming: Location of first frame in eachsymbol.
Future WorkFuture Worky Enhancing the performance of the
implemented CSR UWB system, focusing onthe Synchronization at the frame level of theCSR IR-UWB System.
8/8/2019 UWB Presentation
15/17
ReferencesReferences1. H. Nie and Z. Chen, Code-Shifted Reference Ultra-Wideband (UWB)
Radio, Proc. Comm.NetworksandServicesResearch Conf., pp. 385-389, 2008
2. C. Wei, H. Nie,and Z. Chen, Non-Aided-Data Code Synchronization forthe Code-Shifted Reference Ultr-Wideband (UWB) System, Proc. AnnualComm. NetworksandServicesResearch Conf. 2010, pp. 56-60,
3. C. Carbonelli and U. Mengali, Synchronization Algorithms for UWB
Signals, IEEETrans.On Communications,Vol. 54 No. 2, pp. 329-338, Feb. 2006
4. Biao Liu,etal, A Novel Synchronization Algorithm in Ultra-WidbandSystem, IEEEInt. Conf.on Ultra-Wideband,Sep. 2009, pp. 556-559
5. Mario R. Casu1 and Giuseppe Durisi, Implementation aspects of atransmitted-reference UWB receiver, Wireless CommunicationsandMobileComputing,Vol. 5,pp. 537549, 2005.
6. Nekoogar, Faranak. Ultra-WidebandCommunications:FundamentalsandApplications,Upper Saddle River, NJ : Prentice Hall Professional TechnicalReference, 2005
8/8/2019 UWB Presentation
16/17
ThankYou
8/8/2019 UWB Presentation
17/17
top related