As a result of recent advancement in sensors,
processors, usage of multi-UAV is rapidly evolved their usage in natural
calamities such as drought, flood ,emergency, military and in civilian and
commercial area. FANETs is evolved to tackle communication between multi-UAV(Unmanned
Aerial Vehicle) . The main challenge in FANET is routing because of high
mobility and long distance between UAVs ,The routing protocols designed for
VANET and MANET partially failed in FANET; In this paper we have studied
different routing protocols for FANET.
UAVs are used in many Applications
such as emergency, battlefield,
Traffic & crop monitoring,
search and rescue etc, Because of low Cost , Easy installation, better flying
capabilities. Co-operating between multiple UAVs useful in many ways although it’s a major
challenge in FANETs too.
FANET is a subclass of MANET where
there is a communication between UAVs in wireless fashion but they make use of
location tracking devices or satellite for central administration of multi UAVs
, in wireless network we are not allowed to use any central administration thus
it break basic principle of ad-hoc network,
Common characteristics of FANET
1.high mobility of nodes
2,low node density
3. rapid change in topology
4. nodes are located high above the
ground level and there LoS accessible in most cases
5. Nodes computing power is very
6. GPS, AGPS , DGPS, provided for
There are many routing protocols
used in wireless and ad-hoc networks such as flooding, dynamic source routing,
and pre-computed routing etc. But due to speed of UAVs and rapid changes in links between nodes,
these protocols need to be modified and the others will be established to adopt
this network issues.
SIX MAIN CLASSES OF FANETs ROUTING
1) Static protocols: They contain a
routing table that is not edited at any time3.
2) Proactive protocols: It contains
a routing table for each node that is refreshed periodically3.
3) Reactive Protocols: It is called
on-demand routing protocol, which fills the routing tables when there is a need
to send data and the path is not known3.
4) Hybrid Protocols: It takes
advantages from proactive and reactive protocols3.
protocols: that use position or area coverage4.
6)Hierarchical protocols: that use
hierarchy model for routing4.
1) STATIC ROUTING PROTOCOLS:
As the name suggest STATIC which
cant be updated so these protocols basic characteristics is in which a routing
table is calculated and feed to the UAVs and it can’t be updated during its
applications. Thus there is no Fault Tolerance for dynamic environment.
Low overhead of control messages as there no need for updation.
No Fault Tolerance in Dynamic Envionment.
a) Data Centric Routing: This
method is selected when data is requested by a number of nodes and data
distribution is on-demand process. Data requesting and gathering is done on the
basis of data attributes instead of sender and receiving nodes. This model
works well in clustering, the consumer node broadcast queries in order to
collect data from a particular area. Routing is done with respect to the
content of data. Data aggregation algorithms may be used for energy efficient
data broadcasting. This routing executes three scopes of decoupling:
• Space decoupling: Communicating
parties can be anywhere.
• Time decoupling: Data can be
transmitted to the subscribers instantly or later.
• Flow decoupling: Delivery can be
b) Load Carry And Deliver
Algorithm:In this model, a UAV loads data from a Fixed ground node; then the
data is being carried to the destination by flying; and at the end the data
reached to the Fixed destination ground node. this algorithm always used a pipelined routing path. The main objectives
of load carry and deliver routing is to maximize throughput and increase the
security. And the main drawback of this protocol is whenever the distance of
communicating parts growth, the transmission delay becomes tremendously huge
and unendurable. To solve this problem multi-UAVs system can be developed so
that it decreases transmission delay as well as the distance among UAVs.
Multi-level Hierarchical Algorithm:In this model the network is divided
into hierarchy of clusters .Each cluster has a cluster head (CH), which will
represent the whole cluster; this CH do most of the processing . Each CH is in connection with the
upper/lower clusters containing multiple layers (ground stations, UAVs, satellites, etc.) directly or
indirectly. To broadcast data and control info to other UAVs in the cluster, CH
should be in direct communication range of other UAVs in cluster. This model is
better if UAVs are controlled in larged mission area, and several UAVs are used
in the network.
2)PROACTIVE ROUTING PROTOCOLS:
These protocols make use of routing
tables to store all routing information in the network.
of PRP are: Easy to find out routing path in less Transmission delay as all the
information is already store in tables. Latest information is carry out by
Large number of message exchange to update routing table thus bandwidth wasted.
Thus these protocols not used in high mobility environment.
Directional Optimized Link State Routing: This protocols based on
OLSR(Optimized Link State Routing). Here sender node selects a set of MPR(Multi
Point Relay) nodes so that the MPR nodes can cover two hop neighbours. DOLSR
can reduce the number of MPRs with directional antennas which is most crucial
issue in OLSR.
Destination Sequence Distance Vector (DSDV) routing protocol: In DSDV, each
node saves a routing table (with sequence number and distance ) for all other
nodes. Whenever the topology of the network changes, Routing table is exchanged
by using more number of exchange messages. Destination Sequence Number (Issued
by Destination Node) is used to eliminate routing loops and maintain fresh
information. The main advantages of DSDV are its simplicity and the use of
sequence number. Disadvantages are. For
updation of routing table, each
node periodically broadcast routing table updates, which brings overhead to the
c) Topology Broadcast Based on
Reverse Path Forwarding: This Protocol
Based On DSR (Dynamic Source Routing), developed for dissemination of link
In TBRPF each routing table contains the state (valid/invalid/loop) of each
link. If there is any change in the state of link, it is quickly detected and immediately
find an alternative path therefore it is suitable for FANET. The process of
TBRPF consists of two steps;
first, it perform neighbour
second it broadcast link state
uses min-hop path spanning trees rooted at the source to send the updates
efficiently. The tree is used to travel topology updates using reverse path
REACTIVE ROUTING PROTOCOL(RRP): RRP referred to as On-Demand Routing Protocol.
If there is no data to transfer there is no need to find a route between two
are two different messages in this protocol: Route Request messages (RREQ) and
Route Reply messages (RREP). RREQ Messages are Broadcasted by Source Node and
RRP is the Response from Destination node.
Advantages: Efficient Utilization
of Bandwidth because there is no periodic messages and overcome overhead
problem as in PRP.
Disadvantage: High path Set up Delay.
Dynamic Source Routing (DSR): In DSR, the source node broadcasts a route
request message to its neighbour nodes in its vicinity which include (TTL,
Path, sequence number, source ID and Destination ID) when this message is
received by Destination Node it Start Backtracking the path stored in RREQ
packet and this backtracking in unicast fashion and send RREP to its backtrack node
until it is received by source node and as route is established then data
transmission can take place.
Ad-Hoc On Demand Vector Routing (AODV) :
AODV, there is a single record for each destination and the source node only
stores the next-hop
consistent to each data communication. AODV routing protocol consists of three
packet transmitting and route maintaining. Its RREQ packet contain (Source ID,
Sequence number, Source sequence number, next hop, Broadcast ID which is
c) Time Slotted On-Demand Routing:It
is the time slotted version AODV, It uses dedicated time slots in which only
one node can send data packet. Although it increases the use of network
bandwidth but mitigates the packet collisions and ensure packet delivery.
4.) HYBRID ROUTING PROTOCOLS (HRP):
It overcome the limitation of PRP
and RRP. As RRP need Extra Time for route Discovery and huge overhead in PRP. HRP is appropriate for
large networks. A network can be divided into a number of zones where within
the Zone we used PRP while inner-zone routing uses RRP.
Advantages: low space utilization,
Efficient bandwidth Utilization using Multicasting, less delay if source and
Destination lie in same zone.
a) Zone Based Routing Protocol: ZRP
is based on the concept of Zones in Zone is defined by predefined Radius R. The
Nodes maintain a routing table for nodes which lie within R hop distance and
outside of it, it process RRP by sending RREQ packet for highest hop distance
routing inside the zone is called as intra-zone routing, and it uses proactive method. If the source and
destination nodes are in the same zone, the source node can start data communication
instantly. When the data packets need to send outside the zone the inter-zone
routing is used and reactive method is applied using Multicasting.
b) Temporarily Ordered Routing
Algorithm (TORA): Temporarily
Ordered Routing Algorithm (TORA) routers only preserve info about adjacent
routers . TORA mainly uses a reactive routing protocol but it also use some
proactive protocol. It constructs and preserves a Directed Acyclic Graph (DAG)
from the source node to the destination. TORA does not use a shortest path
solution. Each node has a parameter value termed as “height” using 5 tuples in DAG, which is unique for each node. Data
flow from the higher height nodes to lower height node that is Downstream . It
is loop-free because data always flow in downstreaming path not upstreaming. It
has 3 mechanism : Route Creation, Route Maintenance, Route Erasure.
5.) POSITIONAL BASED ROUTING
routing needs information about the physical position of the contributing nodes
in the network. Generally, each node calculates its own location through the
use of GPS or some other type of positioning facilities. Position based routing
is primarily motivated by two subjects,
(i) A position facility is used by the sender
of a packet to decide the position of the destination and
(ii) A forwarding
approach used to forward the packets.
Greedy Perimeter Stateless Routing: GPSR is a responsive and efficient
routing protocol for mobile, wireless networks. GPSR exploits the
correspondence between geographic
position and connectivity in a wireless network, by using the
positions of nodes to make packet forwarding decisions. GPSR uses greedy forwarding to forward
packets to nodes that are always progressively closer to the destination. In
regions of the network where such a greedy path does not exist (i.e. the only path requires that one
move temporarily farther away from the destination), GPSR recovers by
forwarding in perimeter mode,
in which a packet traverses successively closer faces of a planar subgraph of the full radio network
connectivity graph, until reaching a node closer to the destination, where
greedy forwarding resumes.
Geographic Position Mobility Oriented Routing: In GPMOR Firstly,
they used Gauss-Markov mobility model for predicting the node position to
decrease routing failure. Secondly, they used the mobility relationship to
select next-hop for routing more accurately. The proposed approach improves the
stability of cluster and cluster heads.
HIERARCHICAL ROUTING PROTOCOL:
hierarchical routing protocols the choice of proactive and of reactive routing
depends on the hierarchic level. The routing is primarily established with some
proactive planned routes and then helps the request from by triggered nodes
through reactive protocol at the lower levels. The main drawbacks of this
protocol are: complexity and addressing scheme which response to traffic
request as a result it hang the interconnecting factors.
a) Mobility prediction clustering: It operates on the
dictionary of Tree-structure calculation algorithm and link termination time
mobility model to guess network topology updates. In this way, it can build
more constant cluster
Clustering algorithm of UAV networking: It constructs
the clusters on the ground, and then updates the clusters through the mission
in the multi-UAV system 13.
type of Clustering algorithms are there :
I.LEACH(Low Energy Adaptive
Clustering Hierarchy): LEACH is a
typical hierarchical clustering routing protocol, which adopts distributed
clustering algorithm where cluster-head rotation mechanism, data aggregation,
and data fusion technologies effectively improves the lifetime of network. In
order to optimize energy in the network, nodes are selected as cluster head
circularly and randomly. The normal nodes called cluster members join the
corresponding cluster head nodes on the basis of principle of proximity. Normal
nodes sense data and send directly to the cluster head nodes. The cluster head
nodes receive sensed data, aggregate the data to remove redundancy and fusion
processes are carried out and data is send to the Base Station
II.EECA(Energy Efficient Clustering
Algorithm): In this algorithm the energy loss per cluster round is decreased
and have less number of transmission and a better data hierarchy. The cluster
heads on each round is selected from all the multipoint relays of the network
on the basis of residual energy of all the multipoint relay (MPRs) nodes and
the distance between them and the base station. Now these cluster head chosen
act as a base station and further in the cluster of this cluster head,
sub-cluster heads are choose from the multipoint relays of the nodes in this
cluster on the basis of their distance to this cluster head and energy levels,
thus forming a sub cluster which further goes on to make another sub-sub
cluster and thus continuing this process till the last node in a particular
cluster is covered. Therefore, a hierarchy of clusters is formed.
OF SOME OF THE PROTOCOLS1:
Load Carry and Deliver: High throughput by arranging multiple UAVs in
Data Centric Routing Algorithm: Used
when limited number of UAVs for particular applications.
Topology Based Reverse Path
Forwarding: reduce overhead.
DOSLR: Lower end to end delay.
DSR: Adaptable to Dynamic Topology
AODV: Suitable for dynamic nature
and reduced packet collision.
Time Slotted ON Demand Routing
protocol: Enhanced packet delivery.
GPSR: Outperform many existing non
position based protocol
GMPOR: Better latency, packet delay
ratio position based protocol
Mobility Prediction Algorithm: Increase the stability
of clusters and CH
Clustering Algorithm: Increase the stability,
guarantee the ability of dynamic networking
The routing protocols for FANET are
currently taking more interest of researchers due to their different
characteristics. Here we have tried to mention almost maximum number of
protocols used for FANET. Since there is a lot of work to do in this particular
field and there is a need to find more efficient routing protocols.
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Computer Science and Applications, Damer Jordan University of
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Tareque, Md. Shohrab Hossain& Mohammed Atiquzzaman “On the Routing in
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