Title: Efficient Geographic Routing for Mobile Ad-hoc Networks (Joint work with Xiaojing Xiang)
1Efficient Geographic Routing for Mobile Ad-hoc
Networks(Joint work with Xiaojing Xiang)
- Xin Wang
- Assistant Professor
- Director, Wireless and Networking Systems Lab
(WINS) - SUNY, Buffalo
- http//www.cse.buffalo.edu/xwang8
2Future - Common Network, Common
Applications
3G CellularNetworks
RadioController
AccessRouter
UrbanNetworks
- Outdoor Areas
- High Mobility
AggregationRouter
- Broadband Distribution Networks
- High Speed Pico Cells
- Broadband
- Wireless
Presence
EnterpriseNetworks
Location
AccessRouter
- 802.11
- Local Mobility
- Packet Voice
- High Data Rates
Core InternetBackbone
AggregationRouter
AggregationRouter
Authentication
HomeNetworks
Emerging Techniques
AccessRouter
- DSL/Cable
- Community
- wireless
- networks
Ad HocNetworks
- Personal area
- Sensors
- Actuators
- Allow Peer-to-Peer Communications
- Self Configuring
4GRadios
3Talk Overview
- Background and motivation
- Part I Self-adaptive geographic unicast routing
- Part II Scalable geographic multicast routing
- On-going and future work
4Background
- Mobile Ad Hoc Networks (MANET)
- Routing find a packet delivery path
- Unicast one-to-one
- Multicast one-to-many or manyto-many
5Challenges of MANET Routing
- Host mobility leads to dynamic topology rate of
link failure/repair increases with moving speed - Topology and routing path maintenance become more
difficult with the increase of path length and
node density - Mobile devices have very limited energy, and
small devices such as sensors have very limited
per-node resources -
6Unicast Routing
Reactive
Geographic
Proactive
(GPSR, GFG)
(DSR, AODV, TORA, FLR)
(DSDV, OLSR)
Hybrid
(ZRP, SHARP)
7Information Required for Geographic Routing
- A nodes own position obtained through
positioning service such as GPS
- The position of the destination determined
through location service
- The positions of all neighbors learned through
periodic beacons sent by neighbors
8Forwarding Formats
- Greedy forwarding
- Make local optimal forwarding
decision
D
x
9Issues with Classical Geographic Routing
Proactive fixed-interval beaconing for positions
Difficulty in beaconing Interval setup
Continuous retransmission
Too short consume energy and create collisions
Reduce throughput and fairness
Generate unnecessary overhead and consume energy
Too long outdated topology
Create collisions with normal data transmissions
Further delay and energy consumption
Non-optimal routing, transmission failure
More resource consumption
10Possible Performance Improvement
- Change Beacon Sending Interval
- Send out beacons only after moving a certain
distance - Send beacons more frequently, e.g. piggyback
position with packets (Are the sending nodes the
best next hop? )
Does not consider traffic conditions. May
generate unnecessary beacons.
- Do not use Beacons (CBF03, BLR04)
- Focus only on finding the next hop for greedy
forwarding, and there is no recovery strategy - Do not have a good strategy to use the path
detected or perform any route optimization.
11Talk Overview
- Background and motivation
- Part I Self-adaptive geographic unicast routing
- Part II Scalable geographic multicast routing
- On-going and future work
12Our Contributions
- Propose two self-adaptive routing protocols
BIGR Beaconless Interactive Geographic Routing
BTGR Beacon-on-Trigger Geographic Routing
On demand Alleviate unnecessary overhead due
to proactive beacons
Self adaptive Adaptive to traffic pattern and
topology changes
More flexible position distribution More
updated topology, more efficient routing and
less failure
13Importance of updated positions some analysis
- Positions obtained may become outdated
- A mobile may move out of neighbors transmission
range. - Analysis assumptions
- B sends beacons periodically to refresh its
position - Neighbor area of A centered at A, within
transmission range R - Moving area of B centered at B, within r
Neighbor time-out interval t
Bs speed relative to A
Current distance between A, B
Maximum distance traveled by B after t
14Different Scenarios
R
R
r
z
z
A
B
R
r
A
B
z
B
A
r
Same as this case
15Probability of Moving Out of Range
Case 1
Case 2
Case 3
16Probability of the mobile moving out-of-range
(expressed in percentages)
Timeout
Vmax 4s 6s 8s 10s 12s 14s
10m/s 3.57 5.49 7.51 9.64 11.88 14.27
20m/s 7.51 11.88 16.80 22.43 29.19 38.26
30m/s 11.88 19.51 29.19 42.94 55.38 65.24
40m/s 16.80 29.14 47.37 62.22 72.89 80.07
50m/s 22.43 42.94 62.22 75.00 82.64 87.24
17Proposed Geographic Routing Protocols
- BIGR Beaconless Interactive Geographic Routing
- BTGR Beacon-on-Trigger Geographic Routing
18Beaconless Interactive Geographic Routing (BIGR)
- There is no beacon, routing path is built
on-demand
- Route searching phase
- Route optimization phase
D
x
How to find next hop without positions of
neighbors?
19Proposed Geographic Routing Protocols
- BIGR Beaconless Interactive Geographic Routing
- Route searching
- Route optimization
- BTGR Beacon-on-Trigger Geographic Routing
20Route Searching
- After a route searching, a node keeps a record
for next hop (for node B)
Destination F
Dests position, time (x_F, y_F), t
NextHop C
New position, time (x_new, y_new), t_new
Old position, time (x_old, y_old), t_old
Transmission mode greedy or recovery
Next-hop position
A
Network node
Forwarding node
F
Destination
Next Hop
B
C
21How to find next hop?
- When a node (C) does not have next hop
information, broadcast REQ
S
E
F
B
M
L
C
J
A
G
H
D
I
K
N
Within neighborhood
Dest DestPos SendPos Hop
D XD, YD Xc, Yc 1
A node that receives a packet for the first time
REQ message with
22Forwarding Node Selection
- Reply sending nodes closer to destination
respond after a competition delay delay is
smaller for a node closer to destination
- Reply suppression a node cancels its reply if it
overhears packet forwarding, or overhears reply
sent by node closer to destination
- Multiple replies select the node closer to the
destination as next hop
S
E
F
B
M
L
C
J
A
G
H
D
I
K
N
Dest Sender SendPos Hop
D G XG, YG 1
REPLY message
23Packet Sending
Destination D
Dests position, time (x_D, y_D), t
NextHop G
New position, time (x_new, y_new), t_new
Old position, time (x_old, y_old), t_old
Transmission mode greedy
S
E
F
B
M
L
C
J
A
G
H
D
I
K
N
24Recovery from Local Void
- Without local topology, cannot use perimeter
forwarding. How to recover?
- Broadcast REQ to N-hop neighbors
F
E
S
B
M
C
L
J
A
D
H
I
K
G
N
Dest DestPos SendPos Hop
D XD, YD Xc, Yc 2
REQ message with
25Finding Path in Recovery Mode
- If one-hop neighbor is nearer to destination, it
replies with Hop 1 Otherwise continues
broadcasting REQ - A two-hop neighbor nearer to destination replies
(reverse path), Hop 2
- Reply suppression drop the REPLY if having
forwarded/overhead one from the node closer to
destination
- Multiple replies select the node closer to
destination
F
E
S
Dest Sender SendPos Hop
D G XG, YG 2
B
M
C
L
J
Reply message
D
H
I
K
G
26Proposed Geographic Routing Protocols
- BIGR Beaconless Interactive Geographic Routing
- Route searching
- Route optimization
- BTGR Beacon-on-Trigger Geographic Routing
27Position Update and Route Optimization
- Update next hop position when overhearing packet
forwarding by next hop
Old position
Next hop
New position
Route searching
Invalid
Outdated
- Optimize routing path three cases
28Case 1 A is the destination
- As A is the destination, B should send packet
directly to A, so A sends CORRECT to B
A
B
C
29Case 2 Greedy Mode Forwarding
A
F
- If A is closer to F than C is to F, A sends
CORRECT to B
B
C
- B compares As and Cs positions to F, and sets
its next hop to A if it is closer to F
Greedy
30Case 3 Recovery Forwarding
F
- If A is closer to F than B and C are to F , A
sends CORRECT to B
A
D
B
- B compares A and Cs positions relative to F, if
A is closer to F, B sets its next hop to A
C
Recovery mode
Greedy
- If B is the first hop of recovery, change mode to
greedy
31Proposed Geographic Routing Protocols
- BIGR Beaconless Interactive Geographic Routing
- BTGR Beacon-on-Trigger Geographic Routing
32Position Distribution and Path Finding
- Position distribution through beacons
- Packet forwarding greedy, perimeter
- Beacon generation triggered by data traffic and
route optimization
- Topology maintenance positions of neighbors
33Route Optimization
- Route validation
- Delete invalid neighbors
- Update the positions of other members based on
estimation - Route optimization also three cases
- The first two cases are
similar to those of BIGR - Case 3
- If A is closer to the destination
than where the perimeter
mode started, broadcasts a beacon
D
F
A
O
Greedy
B
Perimeter
C
Perimeter
34Performance Impact of Mobility
- Delivery ratio Control
overhead
35Performance Impact of Mobility (cont)
Transmission inefficiency Average end-to-end
delay
Our protocols have significantly lower
transmission redundancy and end-to-end delay than
GPSR due to more updated topology.
36Summary of Unicast
- Propose two self-adaptive on-demand geographic
routing protocols
37Talk Overview
- Background and motivation
- Part I Self-adaptive geographic unicast routing
- Part II Scalable geographic multicast routing
- On-going and future work
38Multicast Routing
Tree-based
Mesh-based
Geographic
(AMRIS, MAODV, LAM)
(FGMP, CAMP, ODMRP)
(LGT, DSM, PBM)
- Only consider forwarding
- Not scalable
Difficult to scale due to overhead for route
searching, group membership management, and
tree/mesh maintenance over dynamic topology
39Why Is Geographic Multicast Difficult to Scale?
- Putting the information of all group members into
packet header creates excessive overhead for
large group
- Relying on location service to obtain positions
for all group members adds more overhead
40Our Contributions
- Propose scalable geographic multicast routing
protocol - (SGMP)
Designs on-demand hierarchical group membership
management scheme
Uses geographic forwarding to avoid building and
maintaining tree/mesh structure
Introduces the home zone to avoid periodical
network-range flooding of source information
Combines group membership management with
location service to avoid location searches for
all group members
41Terms Used in the Scalable Multicast (SGMP)
42High Level Picture
RFRESH (Join)
REPORT (Join)
DATA
43Source Announcements
- At session initiation time floods an ANNOUNCE,
with address, position, and group ID - During packet transmissions piggybacks its
position with the multicast packets
44Home Zone Management
Home zone searching
Home zone update
Home zone SEQ 1
Home zone SEQ 0
Home zone election
45Membership Management within Zone
- Sends REFRESH to leader (periodically, join,
leave), carrying its membership and position
- Floods LEADER periodically within the zone,
carrying its own position and the positions and
group IDs of the multicast members
46Membership Management at Upper Tier
- Source records the member zones
Leader knows source location
Membership report
SOURCE message
Home Zone
Leader does not know source location or Source
information is outdated
47How to Handle Movement between Zones?
- When a node moves into a new zone
- Clears old zones information
- If the node is a group member
- Will continue receiving packets forwarded by old
zone - Sends next REFRESH to new zone leader
- When a leader is moving out of a zone
- Hands leadership to other nodes
48Empty Zone Problem
20 40 60 80 100
100m 74.885 56.282 44.864 36.865 30.853
200m 36.857 19.208 10.985 6.5467 3.9951
400m 6.4964 0.9643 0.1605 0.0281 0.0051
600m 0.5930 0.0112 0.0002 5.4E-06 1.2E-07
49How to Handle Empty Zone ?
Home zone searching
Home zone update
Member zone empty
Home zone Empty SEQ 1
50Multicast Packet Delivery
- Source
- Sends packets to all member zones and members in
its zone - Sends one copy if several members share next hop
- Intermediate nodes
- Take similar action
- Replace the ID of its current Zone with the
information of the members in the zone.
Source
Zone leader
Group member
Other nodes
51Performance Impact of mobility
- Delivery ratio Control overhead
52Performance Scalability
Group size Network size
53Summary of Multicast
- Design a scalable geographic multicast routing
scheme
Performance scalable in terms of group size,
number of groups, and network range, and robust
to topology change
54On-going Projects
- Cross-Layer optimization and integration of
network infrastructure - Develop key understanding of the cross-layer
interactions, and design more scalable, reliable
and adaptive networking system.
Cooperative resource management for IP-based
Wireless Access Network
Power control and energy efficiency for MANET
INFOCOM04 INFOCOM05
INFOCOM03 INFOCOM04 JSAC05 TMC05
NSF
NIJ
55On-going Projects (cont)
- Next Generation Mobile Wireless Network
Infrastructure and Service - Development of network infrastructure and
services over emerging radio and computing
technologies.
Scalable and resilient wireless mesh network
Context-aware mobile computing and services
Programmable wireless networking and service
infrastructure design
Sensor network applications and Services
- Architecture and Design for Heterogeneous Networks
56Q A
57Performance Studies
- Setup
- Tool GlomoSim
- Network size 3000 m x 1000 m, 300 nodes
- Traffic 30 CBR with rate 8kbps each
- Mobility model Random Waypoint
- Measures
- Packet delivery ratio
- The ratio of packets delivered to those
originated by the source - Control overhead
- The number of control messages over the number of
packets received - Average number of data packet transmissions
- The total number of packet transmissions
accumulated from each hop over the total number
of packets received - Average end-to-end delay
- Average time interval for packets to traverse
from source to destination
58SGMP Basic Principles
Join
Join
(RERESH)
(REPORT)
Zone Leader
Member
Source
Data
Data
Member Zone
Member
Source
Packet sending geographic unicasting, and the
packet for a zone is sent towards the zone
center.
59Performance Number of groups
60Home Zone Election
- When a node receives a message carrying home zone
ID different from that in its record - If the message has larger sequence number,
update its home zone info otherwise, forward the
message to recorded home zone
Home Zone SEQ 0
Membership report
SOURCE message
Home Zone SEQ 1
61Impact of node density
62Impact of node density (cont)
63Impact of traffic load
64Impact of traffic load (cont)
65Performance Impact of node density
66Existing Unicast Routing Protocols
- Proactive protocols (DSDV, OLSR)
- Maintain routes continuously, large overhead
- Actively track network topology, not suitable for
high mobility
- Reactive protocols (DSR, AODV, TORA, FLR)
- Maintain routes only if needed
- Flooding to discover routes, larger delay due to
searching
- Hybrid protocols (ZRP, SHARP)
- Combine the proactive and reactive approaches
- Geographic routing protocols (GPSR, GFG)
- Make use of location information to reduce
routing overhead - Only need to be aware of local topology
67Performance Impact of node density
68Overhead
Group size
Network size
69Impact of the number of groups
70 Tomorrow Common Net, Common Apps
3G CellularNetworks
RadioController
AccessRouter
UrbanNetworks
- Outdoor Areas
- High Mobility
AggregationRouter
- Broadband Distribution Networks
- High Speed Pico Cells
Presence
EnterpriseNetworks
Location
AccessRouter
- 802.11
- Local Mobility
- Packet Voice
- High Data Rates
Core InternetBackbone
AggregationRouter
AggregationRouter
Authentication
HomeNetworks
AccessRouter
- DSL/Cable
- High Speed Internet Access
Ad HocNetworks
4GRadios
- Allow Peer-to-Peer Communications
- Self Configuring
- Unifies access technologies (wireless and
wireline) - End-to-end Internet Service
- common mobility management and control
- common transport infrastructure
- common services infrastructure
71- Architecture and Design for Heterogeneous
Networks - Enable end-to-end communications over
heterogeneous networks WPAN, WLAN, WMAN, W-WAN,
and Internet. -
- Secure and Cooperative Routing over Ad Hoc
Networks - Provide security and incentive to enable the
relay-based hop-by-hop transmissions.
72Beacon Triggering by Data Traffic
- Three types of beacons (for position information)
- BEACON message
- REQ (Carrying position)
- Data packets (Carrying position)
- Beacon request
- Receiving REQ
- Overhearing data transmission
- Beacon sending
- Only if the request interval is smaller than
threshold - For packet sending
- Use local topology information for forwarding if
request sent interval is smaller than threshold - Otherwise, send REQ to neighbor
73Route Searching
- How to find a path without beacon?
- Depend on forwarding states greedy or recovery
- Greedy forwarding
- Find a neighbor closest to the destination
- Recovery forwarding
- How to forward when there is no neighbor closer
to the destination?
74Membership Management in Local Zone
- Membership reporting by mobiles nodes
- Leader election
- Moving between different zones
75Membership Reporting in Local Zone
- A group member sends REFRESH to leader to report
its membership - If leader is known, unicast
- If leader is not known, elect leader
- Leader election (on demand)
- Flood the REFRESH, indicating leader information
is requested - A leader will send back a LEADER message
- If no LEADER is received, the member announces
itself as the leader and floods a LEADER message
within the zone
Zone leader
Group member
Other nodes
76Membership Management at Upper Tier
- A source needs to record the member zones
- Source announcement
- Home zone election
- Zone membership reporting
77Protocol Overview
- Group membership management
- Packet forwarding
- At local zone tier, a leader will collect the
positions and membership of the member nodes in
the zone. - At upper tier, the leader will represent the
member zone to join a multicast tree. - At upper tier, the source sends a packet to
member zones At lower tier, the first node in
the zone that receives the data packet forwards
it to the group members. - Both data and control packets are generally
transmitted through geographic unicasting
Packets for a zone are sent towards the zone
center
Location of group members is combined with
group membership management
78Case 1 A is the destination
- As A is the destination, B should send packet
directly to A, so A sends CORRECT to B
A
B
C
Old path
Old position
Current position
New path
79Case 2 Greedy Mode Forwarding
A
F
- If A is closer to F than C is to F, A sends
CORRECT to B
B
C
- B compares As and Cs positions to F, and sets
its next hop to A if it is closer to F
Greedy
Old path
Old position
Current position
New path
80Case 3 Recovery Forwarding
F
- If A is closer to F than B and C are to F , A
sends CORRECT to B
A
D
B
- B compares A and Cs positions relative to F, if
A is closer to F, B sets its next hop to A
C
Recovery mode
Greedy
- If B is the first hop of recovery, change mode to
greedy
81Route Optimization
- Route validation
- Delete invalid neighbors
- Update the positions of other members based on
estimation - Route optimization also three cases
- The first two cases are
similar to those of BIGR - Case 3
- If A is closer to the destination
than where the perimeter
mode started, broadcasts a beacon
F
A
D
O
Greedy
B
C
Perimeter
82Beaconless Interactive Geographic Routing (BIGR)
- There is no beacon, routing path is built
on-demand
- Route searching phase
- Route optimization phase
D
x
How to find next hop without positions of
neighbors?
83Position Update and Route Optimization
- Update next hop position when overhearing packet
forwarding by next hop (carrying sending node
position)
- Validate next hop
- Estimate next hop
- If both old and new positions are fresh
- If only new position is available, it will be
used as the estimated position - Search for new route
- If both old and new positions are outdated
- If estimated position is out of transmission
range or no longer closer to destination than
current forwarding node
- Optimize routing path three cases
84Existing Multicast Routing Protocols
- Tree-based (AMRIS, MAODV, LAM)
- Utilize network resources efficiently
- Mesh-based (FGMP, CAMP, ODMRP)
- Robust
Difficult to scale due to overhead for route
searching, group membership management, and
tree/mesh maintenance over dynamic topology
- Geographic multicast (LGT, DSM, PBM)
- Only consider packet forwarding scheme
- Reduce topology maintenance overhead, but not
scalable
85Summary of Multicast
- Design a scalable geographic multicast routing
scheme - Scalable group membership management and robust
packet forwarding - Avoid the need to build and maintain the
tree/mesh structure over dynamic topology - Avoid network-range flooding of source
information and location searches for the group
members - Performance scalable in terms of group size,
network range and mobility
86How to Manage Home Zone ?
- Home zone information update
- Home zone searching
- Home zone election
- A source sends its zone ID to home zone when
moving to new zone - The first home zone node floods source info to
whole zone
- Other nodes search home zone with ring of
increasing size. - Source announces its current zone as home zone,
and sets sequence number to 0 sequence number
increases by one each time home zone changes.
- Will be triggered when a node receives a message
addressed to home zone with ID different from
record (due to zone update or zone announcement
from a new source)
87How to Handle Empty Zone ?
- Member zone
- The departing leader notifies the source
- Home zone
- The last node
- 1) Announces the new zone it is moving to as
the home zone 2) Floods source information
within new home zone - 3) Sends ANNOUNCE to network with sequence
number of home zone increased by one
88On-going Work
- Cross-Layer Optimization and Design of Mobile and
Wireless Systems - Create infrastructure and algorithms to enable
more optimal performance of the wireless system,
by adopting an integrated, multi-layer approach - On-going projects
- Power control and energy efficient transmissions
in mobile Ad Hoc networks - Architecture design and cooperative resource
management for IP-based radio access network
Power control and energy efficiency for MANET
89On-going Work (cont)
- Next Generation Mobile Wireless Network
Infrastructure and Service - Development of network infrastructure and
services over emerging radio and computing
technologies. - On-going projects
- Sensor Network Applications and Services
- Programmable Wireless Networking and Service
Infrastructure Design - Scalable and Resilient Wireless Mesh Network
Design - Context-aware Mobile Computing and Wireless
Services - Architecture and Design for Heterogeneous Networks
90Our Contributions
- Design an efficient on-demand hierarchical group
membership management scheme
- Use geographic forwarding to avoid building and
maintaining tree/mesh structure
- Introduce the home zone to avoid periodical
network-range flooding of source information
- Combine group membership management with
location service to avoid location searches for
group members
91Problems with Classical Geographic Routing
Proactive fixed-interval beaconing for positions
Difficulty in beaconing Interval setup
Difficulty in beaconing Interval setup
Too short consume Energy and create collisions
Generate unnecessary Overhead and consume energy
- Proactive fixed-interval beaconing for positions
- Beaconing interval affects accuracy of the local
topology and routing performance - Outdated topology gt non-optimal routing,
transmission failures gt more network resource
consumption - Continuous retransmissions due to inaccurate
position - Reduce link throughput and fairness, and increase
collisions gt further delay and energy consumption
Too long outdated topology
Create collisions with normal data transmissions
No optimal routing, transmission failure
More resource consumption
92Our Contributions
- Propose two self-adaptive routing protocols
BIGR Beaconless Interactive Geographic Routing
BTGR Beacon-on-Trigger Geographic Routing
- On demand alleviate unnecessary overhead due to
proactive beacons
- More flexible position distribution more updated
topology, more efficient routing and less failure
- Self adaptive adaptive to traffic pattern and
robust to topology changes