Department of Information Engineering University of Padova, ITALY. Throughput and Energy Efficiency of Bluetooth v2 + EDR in Fading Channels. - PowerPoint PPT Presentation
WCNC 2008 March 31 - April 3 Las Vegas Department of Information Engineering University of Padova, ITALY Throughput and Energy Ef ciency of fi Bluetooth v2 + EDR in Fading Channels A note on the use of these ppt slides: We’re making these slides freely available to all, hoping they might be of use for researchers and/or students. They’re in PowerPoint form so you can add, modify, and delete slides (including this one) and slide content to suit your needs. In return for use, we only ask the following: If you use these slides (e.g., in a class, presentations, talks and so on) in substantially unaltered form, that you mention their source. If you post any slides in substantially unaltered form on a www site, that you note that they are adapted from (or perhaps identical to) our slides, and put a link to the authors webpage: www.dei.unipd.it/~zanella Thanks and enjoy!
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WCNC 2008 March 31 - April 3 Las Vegas
Department of Information EngineeringUniversity of Padova, ITALY
Throughput and Energy Efficiency of
Bluetooth v2 + EDR in Fading ChannelsA note on the use of these ppt slides:
We’re making these slides freely available to all, hoping they might be of use for researchers and/or students. They’re in PowerPoint form so you can add, modify, and
delete slides (including this one) and slide content to suit your needs. In return for use, we only ask the following:
If you use these slides (e.g., in a class, presentations, talks and so on) in substantially unaltered form, that you mention their source.
If you post any slides in substantially unaltered form on a www site, that you note that they are adapted from (or perhaps identical to) our slides, and put a link to the authors
webpage:
www.dei.unipd.it/~zanella
Thanks and enjoy!
A note on the use of these ppt slides:We’re making these slides freely available to all, hoping they might be of use for
researchers and/or students. They’re in PowerPoint form so you can add, modify, and delete slides (including this one) and slide content to suit your needs. In return for use,
we only ask the following:If you use these slides (e.g., in a class, presentations, talks and so on) in substantially
unaltered form, that you mention their source.If you post any slides in substantially unaltered form on a www site, that you note that they are adapted from (or perhaps identical to) our slides, and put a link to the authors
webpage:
www.dei.unipd.it/~zanella
Thanks and enjoy!
WCNC 2008 March 31 - April 3 Las Vegas
Department of Information EngineeringUniversity of Padova, ITALY
Throughput and Energy Efficiency of
Bluetooth v2 + EDR in Fading Channels
{andrea.zanella, michele.zorzi}@dei.unipd.it
Andrea Zanella, Michele Zorzi
WCNC 2008
Special Interest Group on NEtworking & Telecommunications
Speaker: Marco Miozzo
WCNC 2008 March 31 - April 3 Las Vegas
Motivations Bluetooth was designed to be integrated in portable
battery driven electronic devices
Energy Saving is a key issue!Energy Saving is a key issue! Units periodically scan radio channel for valid packets Scanning takes just the time for a valid packet to be recognized Units that are not addressed by any valid packet are active for less
than 10% of the time
WPAN market is expanding and it aims at becoming the standard the facto for short range communications
High Throughput is very welcome!High Throughput is very welcome! Bluetooth v2.0 + EDR (Enhanced Data Rate) promise bit rates up to 3
Mbps and faster node connections
WCNC 2008 March 31 - April 3 Las Vegas
Aims of the work Questions:
Are the Bluetooth promises maintained?
What’s the energy efficiency & throughput achieved by EDR frame
formats in realistic channels?
Which units shall be the Master in point-to-point connections?
Answer
Well, in most cases, we cannot provide univocal answers…
…but we can offer a mathematical model to decide case by case!
WCNC 2008 March 31 - April 3 Las Vegas
Basic ingredients Define realistic radio channel model
Flat Rice-modelled fading channel
BER curves for different modulations taken from the literature
Capture system dynamic by means of a Finite State
Markov Chain (FSMC) State transitions driven by packet reception events
Define appropriate reward functions Data, Energy, Time
Apply renewal reward theorem to get system
performance Throughput, energy efficiency, energy balancing, …
WCNC 2008 March 31 - April 3 Las Vegas
What standard says…
Bluetooth
reception
mechanism
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Physical layer
Basic Rate: 1Mbps GFSK [13]
EDR2: 2Mbps /4-DQPSK [14]
EDR3 8DPSK [15]
[13] J. S. Roh, “Performance analysis and evaluation of Bluetooth networks in wireless channel environment,” ICSNC’06
[14] L. E. MillerandJ. S. Lee, “BER Expressions for Differentially Detected π/4 DQPSK Modulation,” IEEE TRANSACTIONS
ON COMMUNICATIONS, vol. 46, no. 1, pp. 71–81, January1998. [15] N. Benvenuto and C. Giovanni, Algorithms for Communications Systems and their Applications. Wiley, 2002.
WCNC 2008 March 31 - April 3 Las Vegas
0.22 ms
Tslot
=0.625 ms
TDxn
=nTslot
AC HEAD PAYL
GFSK
0.22 ms
Tslot
=0.625 ms
TjDxn
= nTslot
AC HEAD PAYL
GFSK
GUARD SYNCEDR Trailer
DPSK
Baseband frame formatsB
RE
DR
WCNC 2008 March 31 - April 3 Las Vegas
RetransmissionsMASTER
SLAVE
A B B BB
G F H
NAK
ACK
Automatic Retransmission Query (ARQ): Each data packet is transmitted and retransmitted until positive acknowledge
is returned by the destination Negative acknowledgement is implicitly assumed!
Errors on return packet determine transmission of duplicate packets (DUPCK) Slave filters out DUPCKs by checking their sequence number
Slave does nevernever transmit DUPCKs! Slave can transmit when it receives a Master packet Master packet piggy-backs the ACK/NACK for previous Slave transmission Slave retransmits only when needed!
H
B
A X B X DPCK DPCK
WCNC 2008 March 31 - April 3 Las Vegas
Mathematical Analysis
System Model
WCNC 2008 March 31 - April 3 Las Vegas
Mathematical Model Normal State (N)
Master transmits packets that have never been
correctly received by the slave
Duplicate State (D) Master transmits duplicate packets (DUPCKs)
DNND
NDN PP
P
+=π
The steady-state probabilities are, then,
State transition probabilities depend on the reception events…
DNND
DND PP
P
+=π
WCNC 2008 March 31 - April 3 Las Vegas
QuickTime™ and a decompressor
are needed to see this picture.
Reception Event Index Slaves tx
Master tx
Reception events Reception events
Ds = Data successful AC ok, HEAD ok, CRC ok
Df = Data failure AC ok, HEAD ok, CRC error
Hf = HEAD failure AC ok, HEAD error
Af = AC failure AC error
MC state transitions N = enter Normal State
Master tx non-duplicate packets D = enter Duplicate State
Master tx DUPCKs X = loop step
Return in the same state
WCNC 2008 March 31 - April 3 Las Vegas
Reward Functions
∑∈
=EjE
xjj
xDD )()(
π
For each state j we define the following reward functions
Tj= Average amount of time spent in state j
Dj(x)= Average amount of data delivered by unit x{M,S}
Wj(x)= Average amount of energy consumed by unit x{M,S}
The average amount of reward earned in state j is given by
∑∈
=EjE
xjj
xWW )()(
π∑∈
=EjE
jjTT π
Performance indexes Energy Efficiency: Energy Efficiency:
Goodput: G( )( ) T
DD
T
DG
MS )()(
lim+
==∞→ τ
ττ
( )( ) )()(
)()(
limMS
MS
WW
DD
W
D
+
+==
∞→ τ
τξ
τ
WCNC 2008 March 31 - April 3 Las Vegas
Time reward ( T )
( ) ( )9898 )1(1)( ppnppmnT +++−−+=
Master Frame Slave Frame
n+m
n+1
QuickTime™ and a decompressor
are needed to see this picture.
Empty slot
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Data reward ( D )Master’s Data Slave’s Data
QuickTime™ and a decompressor
are needed to see this picture.
Dxn π Dym
Dxn π ---
( )40)( )( ppDLD ym
S +⋅=( )3210)( )( ppppDLD Nxn
M +++⋅⋅= π
No Useful Data
--- ---
--- ---
Dym
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Master energy reward ( W(M))Tx power Rx Power
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are needed to see this picture.
Sx power
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Slave energy reward ( W )
Slave’ energy reward resembles mater’ one except that, in D state, Slave does not listen for the PAYL field of recognized downlink packet since it has been already correctly received!
QuickTime™ and a decompressor
are needed to see this picture.
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Performance Analysis
Results
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AWGN
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are needed to see this picture.
QuickTime™ and a decompressor
are needed to see this picture.
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QuickTime™ and a decompressor
are needed to see this picture.
Rayleigh
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Conclusions
Main Contribution mathematical framework for performance evaluation
of Bluetooth EDR links Results
3DHn yield better performance for SNR>20 dB 2DHn perform better in the low SNR region 1DHn always show poor performance
Results refer to a specific case study, but the analytical model is general
WCNC 2008 March 31 - April 3 Las Vegas
Department of Information EngineeringUniversity of Padova, ITALY
Mathematical Analysis of Bluetooth Energy EfficiencyMathematical Analysis of Bluetooth Energy Efficiency
Andrea Zanella, Daniele Miorandi, Silvano Pupolin
WPMC 2003, 21-22 October 2003
Questions?
WCNC 2008 March 31 - April 3 Las Vegas
Extra Slides…
Spare slides…
WCNC 2008 March 31 - April 3 Las Vegas
( ) ( ) jjS
jok j
AC −
=
−⎟⎟⎠
⎞⎜⎜⎝
⎛=∑ 72
000
0 172
βββ
( ) ( ) ( )( )1830
2000 113 ββββ −+−=okHEAD
Conditioned probabilities
AC HEAD PAYLOAD72 bits 54 bits h=2202745 bits
CRC
Receiver- Correlator Margin (S)
2-time bit rep. (1/3 FEC)
DHn: Unprotected
DMn: (15,10) Hamming FEC
( ) ( )( ) ( ) ( )( )⎡ ⎤1515
014
000
00
1115:DMn
1:DHnh
ok
hok
PL
PL
ββββ
ββ
−+−=
−=00: BER: BER
WCNC 2008 March 31 - April 3 Las Vegas
Hypothesis Single slave piconet Saturated links
Master and slave have always packets waiting for transmission
Unlimited retransmission attempts Packets are transmitted over and over again until positive
acknowledgement
Static Segmentation & Reassembly policy Unique packet type per connection
Sensing capability Nodes can to sense the channel to identify the end of ongoing
transmissions Nodes always wait for idle channel before attempting new transmissions
WCNC 2008 March 31 - April 3 Las Vegas
Packet error probabilities Let us define the following basic packet reception events
Afr: AC does not check
Packet is not recognized
Hf: AC does check & HEAD does not
Packet is not recognized
Df: AC & HEAD do check, PAYL does not
Packet is recognized but PAYL contains unrecoverable errors
Ds: AC & HEAD & PAYL do check
Packet is successfully received
Packets experiment independent error events because of the
