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An Efficient and Reliable MAC for Vehicular Ad Hoc Networks
Duc Ngoc Minh Dang1 , Hanh Ngoc Dang2 , Cuong The Do1 and Choong Seon Hong1 1 Department
of Computer Engineering Kyung Hee University, Korea
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2 Department of Telecommunications Engineering Ho Chi Minh City University of Technology, Vietnam
Asia-Pacific Network Operations and Management Symposium, 2013
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Introduction The VER-MAC protocol Performance Evaluation Conclusion
Outline
Introduction VANETs Related Work
2
The VER-MAC protocol Main idea Data structures: BS, NIL, CUL The operation of VER-MAC protocol
3
Performance Evaluation Simulation Settings Simulation Results
4
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Conclusion
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 2 / 23
AF T
Introduction The VER-MAC protocol Performance Evaluation Conclusion
Outline
VANETs Related Work
Introduction VANETs Related Work
2
The VER-MAC protocol Main idea Data structures: BS, NIL, CUL The operation of VER-MAC protocol
3
Performance Evaluation Simulation Settings Simulation Results
4
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Conclusion
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 3 / 23
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Introduction The VER-MAC protocol Performance Evaluation Conclusion
ITS - VANET
VANETs Related Work
Intelligent Transportation System (ITS): improve quality, effectiveness and safety of future transportation systems. Vehicular ad hoc networks (VANETs): important part of ITS Vehicle-to-Vehicle (V2V) Vehicle-to-Infrastructure (V2I)
VANETs have two applications:
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Safety applications: strict requirements on communication reliability and delay Non-safety applications: throughput-sensitive
Wireless Access in Vehicular Environment (WAVE): operates on 5.9 GHz band with IEEE 802.11p and IEEE 1609 standard family IEEE 1609.4: standard of the multi-channel operation for WAVE MAC
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 4 / 23
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Introduction The VER-MAC protocol Performance Evaluation Conclusion
IEEE 1609.4
VANETs Related Work
Frequency (MHz) Guard Interval (4ms) 5925 CH184(SCH) 5915 CH182(SCH) 5905 CH180(SCH) 5895 CH178(CCH) 5885 CH176(SCH) 5875 CH174(SCH) 5865 CH172(SCH) 5855 Start of UTC Second
Sync Interval CCH Interval SCH Interval (50ms) (50ms) CH184(SCH) CH182(SCH) CH180(SCH) CH178(CCH) CH176(SCH) CH174(SCH) CH172(SCH) Time
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Nodes broadcast SMsgs or negotiate the SCHs on the CCH during the CCHI Nodes switch to the negotiated SCHs for their non-safety message transmissions During the CCHI: high contention resource of SCHs cannot be utilized
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 5 / 23
AF T
Introduction The VER-MAC protocol Performance Evaluation Conclusion
Outline
VANETs Related Work
Introduction VANETs Related Work
2
The VER-MAC protocol Main idea Data structures: BS, NIL, CUL The operation of VER-MAC protocol
3
Performance Evaluation Simulation Settings Simulation Results
4
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Conclusion
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 6 / 23
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Introduction The VER-MAC protocol Performance Evaluation Conclusion
VANETs Related Work
Multi-channel MAC protocols for VANETs Variable CCH interval (VCI) multi-channel MAC:
CCHI = safety interval + WAVE Service Announcement (WSA) interval WSA interval is adjusted according to the network condition
Dedicated Multi-channel MAC (DMMAC)
TDMA-based access scheme Node has to transmit a SMsg successfully in order to reserve a slot
Asynchronous Multi-channel MAC Distributed (AMCMAC-D)
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Nodes make rendezvous with their receivers or broadcast SMsgs on the CCH Applies Distributed TDMA mechanism to reduce the high contention level on CCH
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 7 / 23
AF T
Introduction The VER-MAC protocol Performance Evaluation Conclusion
Outline
Main idea Data structures: BS, NIL, CUL The operation of VER-MAC protocol
Introduction VANETs Related Work
2
The VER-MAC protocol Main idea Data structures: BS, NIL, CUL The operation of VER-MAC protocol
3
Performance Evaluation Simulation Settings Simulation Results
4
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Conclusion
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 8 / 23
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Node broadcasts SMsg in CP at the first time, rebroadcasts in next RP without channel contention
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On SCHs: CCHI/SCHI = TxSlot#1 + TxSlot#2 + ... Nodes exchange WSA or RFS to reserve a TxSlot on SCH for non-safety transmissions Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
CCH Reservation Period
CH#1 (CCH) CH#2 (SCH)
RP
RFS(D-D’)
WSA(E-E’)
SMsg(C)
On CCH: CCHI/SCHI = RP + CP
SMsg(G)
SMsg(F)
All nodes are synchronized
SMsg(B)
RIFS
Node has a half-duplex transceiver
WSA(A-A’)
Main idea
Main idea Data structures: BS, NIL, CUL The operation of VER-MAC protocol
SMsg(D) SMsg(E)
Introduction The VER-MAC protocol Performance Evaluation Conclusion
Contention Period
CP
RP
CP
TxSlot #1 TxSlot #2 DATA DATA (A-A’) (D-D’)
CCH Interval SCH Interval Sync Interval = SI
WSA: WSA/ACK/RES handshake RFS: RFS/ACK/RES handshake DATA: WSA-Data/ACK handshake SMsg: Safety Message SMsg( ) First transmission SMsg( ) Retransmission
An Efficient and Reliable MAC for VANETs
APNOMS 2013 9 / 23
AF T
Introduction The VER-MAC protocol Performance Evaluation Conclusion
Outline
Main idea Data structures: BS, NIL, CUL The operation of VER-MAC protocol
Introduction VANETs Related Work
2
The VER-MAC protocol Main idea Data structures: BS, NIL, CUL The operation of VER-MAC protocol
3
Performance Evaluation Simulation Settings Simulation Results
4
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1
Conclusion
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 10 / 23
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Introduction The VER-MAC protocol Performance Evaluation Conclusion
Main idea Data structures: BS, NIL, CUL The operation of VER-MAC protocol
CCH Reservation Period
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Predecessor → Node → Successor: Broadcast sequence Time (t): the time Node broadcasts the first SMsg during CP
RFS(D-D’)
RIFS
WSA(E-E’)
Time (t) tB tC tG
SMsg(G)
Successor G C
SMsg(B)
Node B C G
WSA(A-A’)
Predecessor G G B
SMsg(F) SMsg(D) SMsg(E)
Node A Node B Node C Node G
SMsg(C)
Broadcast Sequence - BS
Contention Period CCH Interval
B
A
C E
H
G D F
BS is updated whenever node overhears SMsgs from its neighbors Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 11 / 23
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Introduction The VER-MAC protocol Performance Evaluation Conclusion
Main idea Data structures: BS, NIL, CUL The operation of VER-MAC protocol
Neighbor Information List - NIL
CH#1 (CCH) CH#2 (SCH)
CCH Interval
SCH Interval
CCH Interval
TxSlot #1 TxSlot #2 TxSlot #3 DATA DATA DATA (A-A’) (D-D’) (E-E’)
SCH Interval
CCH Interval
SCH Interval
TxSlot #1 TxSlot #2 DATA (C-C’)
DATA (F-F’)
DATA (B-B’)
Time
Shows the neighbor’s status: Channel and Tx_Slot Helps node know when the neighbor node is on the CCH
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Node D E X If Tx_Slot ∈ CCHI: neighbor node is on CCH ... in the next 2 SIs
Channel 2 2 3 ...
Tx_slot 2 3 4 ...
NIL is updated whenever WSA/RFS overheard
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 12 / 23
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Introduction The VER-MAC protocol Performance Evaluation Conclusion
Main idea Data structures: BS, NIL, CUL The operation of VER-MAC protocol
Channel Usage List - CUL
Stores the service channel’s availability
Avail_slot: corresponding SCH and Node are available CUL is used to select the Tx_Slot during the SCH negotiation Sender transmits WSA/RFS with its CUL Receiver selects the best Tx_Slot:
Based on receiver’s CUL and sender’s CUL The "best" TxSlot: followed by the most available slots
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Channel 2 3 4 ...
Avail_slot 4 3, 4 4 ...
CUL is also updated whenever WSA/RFS overheard
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 13 / 23
AF T
Introduction The VER-MAC protocol Performance Evaluation Conclusion
Outline
Main idea Data structures: BS, NIL, CUL The operation of VER-MAC protocol
Introduction VANETs Related Work
2
The VER-MAC protocol Main idea Data structures: BS, NIL, CUL The operation of VER-MAC protocol
3
Performance Evaluation Simulation Settings Simulation Results
4
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Conclusion
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 14 / 23
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Introduction The VER-MAC protocol Performance Evaluation Conclusion
Main idea Data structures: BS, NIL, CUL The operation of VER-MAC protocol
CH#2 (SCH)
TxSlot #1 DATA (A-A’)
CCH Interval
DATA (B-B’)
TxSlot #2 DATA (D-D’)
SMsg(F)
SMsg(B) SMsg(B) SMsg(C) SMsg(G) SMsg(G) SMsg(H)
RFS(D-D’)
WSA(E-E’)
SMsg(C)
SMsg(G)
SMsg(B)
WSA(A-A’)
SMsg(F)
CH#1 (CCH)
SMsg(D) SMsg(E)
The operation of VER-MAC protocol
TxSlot #3 DATA (E-E’)
SCH Interval
Time
1. Node has SMsg:
During RP, broadcast after RIFS without channel contention During the CP, node tries to contend CCH to broadcast SMsg
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2. Node rebroadcast SMsgs during next RP without collision 3. When node sends/requests non-safety messages, it sends the WSA or RFS which piggybacks with its CUL 4. Receiver selects the "best" TxSlot and then sends the ACK indicating the selected TxSlot and SCH to sender Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 15 / 23
AF T
Introduction The VER-MAC protocol Performance Evaluation Conclusion
Main idea Data structures: BS, NIL, CUL The operation of VER-MAC protocol
CH#2 (SCH)
TxSlot #1 DATA (A-A’)
CCH Interval
DATA (B-B’)
TxSlot #2 DATA (D-D’)
SMsg(F)
SMsg(B) SMsg(B) SMsg(C) SMsg(G) SMsg(G) SMsg(H)
RFS(D-D’)
WSA(E-E’)
SMsg(C)
SMsg(G)
SMsg(B)
WSA(A-A’)
SMsg(F)
CH#1 (CCH)
SMsg(D) SMsg(E)
The operation of VER-MAC protocol
TxSlot #3 DATA (E-E’)
SCH Interval
Time
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5. Sender sends the RES to confirm the TxSlot and SCH selected by the receiver. 6. Neighbor nodes, which overhear the ACK or RES messages, update their NILs and CULs. 7. After the CCHI, the sender and receiver only switch to the agreed SCH in the selected TxSlot for their data transmissions. Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 16 / 23
AF T
Introduction The VER-MAC protocol Performance Evaluation Conclusion
Outline
Simulation Settings Simulation Results
Introduction VANETs Related Work
2
The VER-MAC protocol Main idea Data structures: BS, NIL, CUL The operation of VER-MAC protocol
3
Performance Evaluation Simulation Settings Simulation Results
4
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1
Conclusion
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 17 / 23
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Introduction The VER-MAC protocol Performance Evaluation Conclusion
Simulation Settings Simulation Results
Simulation Settings
Consider 10 safety nodes, and 40 non-safety nodes
Safety message is dropped if it is not transmitted within 100ms
Parameters Data rate Safety packet size Non-safety packet size WSA / RFS ACK / RES AIFS[Safety] / AIFS[Non-safety] Safety:CW(min:max) Non-safety:CW(min:max) SIFS / RIFS / DIFS Slot time
Value 6 Mbps 100 bytes 1024 bytes 27 bytes 16 bytes 2/9 (3:7) time slots (7:1023) time slots 16 / 25 / 34 µs 9 µs
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Performance metrics:
The aggregate throughput (Mbps) of non-safety traffic.
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 18 / 23
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Introduction The VER-MAC protocol Performance Evaluation Conclusion
Simulation Settings Simulation Results
Simulation Settings
Consider 10 safety nodes, and 40 non-safety nodes
Safety message is dropped if it is not transmitted within 100ms
Parameters Data rate Safety packet size Non-safety packet size WSA / RFS ACK / RES AIFS[Safety] / AIFS[Non-safety] Safety:CW(min:max) Non-safety:CW(min:max) SIFS / RIFS / DIFS Slot time
Value 6 Mbps 100 bytes 1024 bytes 27 bytes 16 bytes 2/9 (3:7) time slots (7:1023) time slots 16 / 25 / 34 µs 9 µs
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Performance metrics:
The aggregate throughput (Mbps) of non-safety traffic. The average delay (msec) of non-safety traffic.
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 18 / 23
AF T
Introduction The VER-MAC protocol Performance Evaluation Conclusion
Simulation Settings Simulation Results
Simulation Settings
Consider 10 safety nodes, and 40 non-safety nodes
Safety message is dropped if it is not transmitted within 100ms
Parameters Data rate Safety packet size Non-safety packet size WSA / RFS ACK / RES AIFS[Safety] / AIFS[Non-safety] Safety:CW(min:max) Non-safety:CW(min:max) SIFS / RIFS / DIFS Slot time
Value 6 Mbps 100 bytes 1024 bytes 27 bytes 16 bytes 2/9 (3:7) time slots (7:1023) time slots 16 / 25 / 34 µs 9 µs
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Performance metrics:
The aggregate throughput (Mbps) of non-safety traffic. The average delay (msec) of non-safety traffic. The packet delivery ratio (PDR) of safety traffic.
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 18 / 23
AF T
Introduction The VER-MAC protocol Performance Evaluation Conclusion
Simulation Settings Simulation Results
Simulation Settings
Consider 10 safety nodes, and 40 non-safety nodes
Safety message is dropped if it is not transmitted within 100ms
Parameters Data rate Safety packet size Non-safety packet size WSA / RFS ACK / RES AIFS[Safety] / AIFS[Non-safety] Safety:CW(min:max) Non-safety:CW(min:max) SIFS / RIFS / DIFS Slot time
Value 6 Mbps 100 bytes 1024 bytes 27 bytes 16 bytes 2/9 (3:7) time slots (7:1023) time slots 16 / 25 / 34 µs 9 µs
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Performance metrics:
The aggregate throughput (Mbps) of non-safety traffic. The average delay (msec) of non-safety traffic. The packet delivery ratio (PDR) of safety traffic. The SMsg broadcast efficiency (nodes/SMsg): the average number of nodes received a SMsg successfully.
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 18 / 23
AF T
Introduction The VER-MAC protocol Performance Evaluation Conclusion
Outline
Simulation Settings Simulation Results
Introduction VANETs Related Work
2
The VER-MAC protocol Main idea Data structures: BS, NIL, CUL The operation of VER-MAC protocol
3
Performance Evaluation Simulation Settings Simulation Results
4
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1
Conclusion
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 19 / 23
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Introduction The VER-MAC protocol Performance Evaluation Conclusion
Simulation Settings Simulation Results
Performance versus non-safety packet arrival rate Safety packet arrival rate = 20 packets/second (a) Aggregate throughput of non−safety applications
30 25 20 15 10 5 0 0 10
(b) Average delay of non−safety applications
200
IEEE1609.4 AMCMAC VER−MAC
1
Average delay (msec)
Aggregate throughput (Mbps)
35
2
10 10 Non−safety packet arrival rate (packets/sec)
10
150
100
50
0 0 10
3
(c) Packet Delivery Rate of safety message
3
10
45 (nodes/SMsg)
(%)
0.8
0.7
0.5 0 10
2
(d) Average SMsg broadcast efficiency
0.9
0.6
1
10 10 Non−safety packet arrival rate (packets/sec)
50
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IEEE1609.4 AMCMAC VER−MAC
IEEE1609.4 AMCMAC VER−MAC 1
2
10 10 Non−safety packet arrival rate (packets/sec)
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
40 35 30 25
10
3
20 0 10
IEEE1609.4 AMCMAC VER−MAC 1
2
10 10 Non−safety packet arrival rate (packets/sec)
An Efficient and Reliable MAC for VANETs
3
10
APNOMS 2013 20 / 23
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Introduction The VER-MAC protocol Performance Evaluation Conclusion
Simulation Settings Simulation Results
Performance versus safety packet arrival rate
Non-safety packet arrival rate = 300 packets/second (a) Aggregate throughput of non−safety applications 32
180
30 28 26
IEEE1609.4 AMCMAC VER−MAC
24 22
160
IEEE1609.4 AMCMAC VER−MAC
140 120 100 80
20 18 10
(b) Average delay of non−safety applications
200
Average delay (msec)
Aggregate throughput (Mbps)
34
20
30 40 50 60 70 80 Safety packet arrival rate (packets/sec)
90
60 10
100
20
(c) Packet Delivery Rate of safety message
100
(d) Average SMsg broadcast efficiency
0.8
40 (nodes/SMsg)
0.9
(%)
IEEE1609.4 AMCMAC VER−MAC
0.7
0.6
0.5 10
90
45
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30 40 50 60 70 80 Safety packet arrival rate (packets/sec)
20
30 40 50 60 70 80 Safety packet arrival rate (packets/sec)
IEEE1609.4 AMCMAC VER−MAC
35
30
25
90
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
100
20 10
20
30 40 50 60 70 80 Safety packet arrival rate (packets/sec)
An Efficient and Reliable MAC for VANETs
90
100
APNOMS 2013 21 / 23
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Introduction The VER-MAC protocol Performance Evaluation Conclusion
Conclusion
VER-MAC allows nodes to exchange non-safety messages during the CCHI to improve throughput of non-safety applications. VER-MAC uses the reserved retransmission mechanism to increase the reliability of SMsg broadcast. Future work
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Perform analysis for VER-MAC protocol. More simulation scenarios.
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 22 / 23
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Introduction The VER-MAC protocol Performance Evaluation Conclusion
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THANK YOU!
Duc Dang, Hanh Dang, Cuong Do and ChoongSeon Hong
An Efficient and Reliable MAC for VANETs
APNOMS 2013 23 / 23
