PERCOM i H Hipercom project presentation Philippe Jacquet evaluation seminar.
Mohamed Elhawary Computer Science Department Cornell University PERCOM 2008 Zygmunt J. Haas...
-
Upload
sharon-helen-rose -
Category
Documents
-
view
214 -
download
0
Transcript of Mohamed Elhawary Computer Science Department Cornell University PERCOM 2008 Zygmunt J. Haas...
Mohamed Elhawary Computer Science
Department Cornell University
PERCOM 2008
Zygmunt J. Haas Electrical and
Computer Engineering Department
Cornell University
OutlineIntroductionThe Busy Tone Multi Channel Protocol
(BTMC)SimulationConclusion
IntroductionWireless ad hoc network
To increase the capacity multi-channel 802.11 a → 12 802.11 b → 3
The protocols designed for the multi channel environment To solve the hidden terminal problem How the channel rendezvous is done
IntroductionThis is the first MAC protocol
With a single packet radio per node That does not require synchronization or a
dedicated control channel Does not cause network partitioning
MotivationSolve the hidden terminal problem in multi-
channel. No synchronization. We do not want to have a control channel
that can get saturated. All channels can be used for data or control exchange
GoalTo propose a new distributed multi-channel
MAC protocol The Busy Tone Multi Channel Protocol (BTMC)To increase the capacity
MAC protocolTo use a set of k hash functions; h0, h1,…,
hk-1,A channel number from 0 to m-1
where m is the channel environment was described before in previous works number of channels available
Nodes are aware of MAC addresses of each other and have the same set of the hash functions
MAC protocol
A
B
C
E
D
Ch 1
Ch 2
Ch 3
Ch 4
hash function : A {2, 1, 3, 1, 2}
B {1, 4, 2, 1, 3}
C {4, 3, 2, 1, 2}
D {3, 2, 1, 4, 1}
E {1, 4, 3, 4, 2}
A
E
D
BC
MAC protocol
A
E
DC
A B
C
E
D
Ch 1
Ch 2
Ch 3
Ch 4
hash function : A {2, 1, 3, 1, 2}
B {1, 4, 2, 1, 3}
C {4, 3, 2, 1, 2}
D {3, 2, 1, 4, 1}
E {1, 4, 3, 4, 2}
BRTS
MAC protocol
E
DC
Ch 4
A
BRTS
A
B
RTS
2τ+γ
idle
CTS
DATA
Variable definitions: δ: data packet transmission time γ: RTS/CTS transmission time τ: maximum one way propagation delay td: busy tone detection delay
E
2τ + δ + td
searches for the next free channel
MAC protocol
A
E
DC
A B
C
E
D
Ch 1
Ch 2
Ch 3
Ch 4
hash function : A {2, 1, 3, 1, 2}
B {1, 4, 2, 1, 3}
C {4, 3, 2, 1, 2}
D {3, 2, 1, 4, 1}
E {1, 4, 3, 4, 2}
BRTS
MAC protocol
E
DC
Ch 4
A
BRTS A
B
RTS
2τ+γ
Not idle
Busy tone
E
MAC protocol
E
DC
A B
C
E
D
Ch 1
Ch 2
Ch 3
Ch 4
A
BRTS
wait 2τ + 2δ
hash function : A {2, 1, 3, 1, 2}
B {1, 4, 2, 1, 3}
C {4, 3, 2, 1, 2}
D {3, 2, 1, 4, 1}
E {1, 4, 3, 4, 2}
Variable definitions: δ: data packet transmission time γ: RTS/CTS transmission time τ: maximum one way propagation delay td: busy tone detection delay
Experimental results
Experimental results
Experimental results
ConclusionWe proposed a new multi channel MAC
protocol in ad hoc networkTo use one packet radio per nodeIt has a low overhead
Future workWe want to test the effect of using more
sophisticated hash functionsTo save power like in the IEEE 802.11
specifications