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ABSTRACT

Mobile
Cognitive Ad Hoc Networks is the one of the cognitive radio networks
which is the advanced networking technologies for spectrum scarcity
problem constrain in the Federal Communication Commission (FCC). The
cognitive radio networks are the cognitive network which abject its
network parameters with respect to network environment. In cognitive
radio network two users namely the primary and secondary or cognitive
users will access the available spectrum to communicate each other
when the spectrum is accessed by the primary user the secondary user
must leave the spectrum and access the spectrum when spectrum holes
available for transmission. So routing is challenging issues in
cognitive networks and it is very challenging in mobile cognitive
networks due to the node mobility, primary user interface and
spectrum scarcity in this paper some routing protocols based on
mobile ad hoc cognitive networks and a review on the delay-Minimized
routing protocol is presented.
KEY
WORDS
Cognitive
Radio Networks (CRN), Primary Users (PU), Cognitive User (CU), Ad Hoc
Networks.

INTRODUCTION

Cognitive
Radio Networks (CRN) is the new technology used to overcome the
spectrum scarcity problem in current wireless networks by Federal
Communication Commission (FCC). In cognitive radio network is a
network which have primary and secondary users which access the
network based on Dynamic
Spectrum Access (DSA). The primary user is the licensed user and
secondary user is unlicensed user when the licensed user is accessing
the spectrum the unlicensed user are not allowed so the secondary
user has to sense the spectrum periodically to find the presence of
primary user, presence of primary user is in dynamic in nature so the
spectrum holes created by primary user is dynamic so the Cognitive
user uses the DSA. While using the DSA routing is the challenging in
cognitive radio networks.

Classification
of Cognitive radio networks
Cognitive
Radio Networks (CRN) is of infrastructured and infrastructure less,
in infrastructured network it has a fixed structure like base station
primary users secondary users and so on, in infrastructured network
it has no fixed structure.

Centralized
and Decentralized networks the Centralized network is the network in
which has on base station in the central and have primary users are
present. Decentralized network is the network which has no
centralized base station and has the secondary users to communicate
and primary users

Static
and dynamic networks the static networks the position of base
station, primary users and secondary users are fixed but in the
dynamic (Ad-Hoc) the position on primary users and secondary user
will change (Mobility is nature).

Routing
in Cognitive radio networks

Routing
in Cognitive radio networks is based on available spectrum and
knowledge of spectrum to nodes in the network. Routing solutions for
the Cognitive radio networks is of two types one is Full Spectrum
Knowledge routing and second is Local Spectrum Knowledge routing.
Local
Spectrum Knowledge routing has Minimum Power Routing, Minimum
Delay-based Routing, Maximum Throughput-based Routing, Geographic
Routing and Class-based Routing.

ROUTING
PROTOCOLS IN COGNITIVE RADIO NETWORKS
Spectrum-Aware
Routing (SPEAR)
Spectrum-Aware
Routing (SPEAR) is a on demand and link based protocol support
end-to-end throughput by integration of flow-based and link-based
approaches, it used RREQ for route discovery by control channels it
takes decisions with collaboration of PHY and MAC layers it handle
mobility issues with Timeout field in periodic channel reservations
messages. It takes the best path by maximum throughput, minimum hop
count and link quality it has a communication overhead by route setup
and route tear down.

Spectrum-Aware
Mesh Routing (SAMER)
Spectrum-Aware
Mesh Routing (SAMER) is a link state routing protocol with minimum
hop count and spectrum availability it gives end-to-end thought with
the path with high spectrum availability, long-term stability and
short-term opportunistic utilization of spectrum. The routing
decisions are taken by PHY and MAC layers.

Spectrum-Aware
On-Demand Routing Protocol (SORP)
Spectrum-Aware
On-Demand Routing Protocol (SORP) is an AODV protocol with control
channel which uses the path delay and node delay (switching and back
off delay) for path selection. In route discovery phase RREQ message
is broadcast with a SOP append in the packet the control channel
exchange the routing protocol messages and it gives end-to-end
thought put SORP doesn’t have link failure handling mechanism.

Multi-hop
Signal-transceiver Cognitive Radio Network Routing Protocol (MSCRP)
Multi-hop
Signal-transceiver Cognitive Radio Network Routing Protocol (MSCRP)
is an AODV protocol with on control channel. It is a spectrum aware
routing and leaves/ joins messages of the nodes so it has the
communication overhead of RREQ. In route discovery phase all nodes
append their sate information and available channels set. Routing
decision is taken with the collaboration of MAC, Physical and Network
Layers.

Routing
in Opportunistic Cognitive Radio Networks
Routing
in Opportunistic Cognitive Radio Networks is an on demand graph
structured network protocol which uses the routing metric based on
the probabilistic definition of available capacity over channel it
has no link failure handling capacity and it discovers the route by
using OSPF, Dijkstra-link algorithm. By using this Dijkstra-link
algorithm it gives end-to-end throughput

Local
Coordination Based Routing and Spectrum assignment in Multi-hop
Cognitive Radio Networks
Local
Coordination Based Routing and Spectrum assignment in Multi-hop
Cognitive Radio Networks is a modified version of AODV which is on
demand routing protocol it has full mesh topology which uses channel
scanning and beacon broadcast for neighbor discovery with control
channel used for load balancing in routing. The route discovery is
done by using RREQ and route decision is based on MAC and Network
Layer. It has link failure handling capability which gives less
end-to-end delay and performance.

Multipath
Routing and Spectrum Access (MRSA)
Multipath
Routing and Spectrum Access (MRSA) is Mesh routing protocol based on
round robin fashion data striping with minimum hop count by route
discovery with control channel, Broadcasting RREQ messages. The
massages sent to nodes periodically it can handle path failures by
sending RERR messages and it has a communication overhead based on
multiple flows on single radio.

Cognitive
Tree-based Routing (CTBR)
Cognitive
Tree-based Routing (CTBR) is the tree based routing protocol with
centralized routing it broadcast the root announcement (RANN) message
periodically with a packet and used cumulative metric for path
selection. It selects the path based on local and global decision
schemes. It does not have route recovery mechanism to handle link
failures and it has a control bytes transmission overhead.

ROUTING
PROTOCOLS FOR MOBILE COGNITIVE RADIO Ad-Hoc NETWORKS
Fault-Tolerant
Cognitive Ad-Hoc Routing Protocol (FTCARP)
It
is a fast and efficient routing protocol for route recovery in
presence of path failures during data deliver. It uses different
route recovery mechanisms for different path failures.

Cognitive
Destination Sequence Distance Vector (C-DSDV) Protocol
It
is a table driven routing protocol. To optimize the system
performance of multi-hop CR ad-hoc networks by using multichannel
routing table are updated immediately when there is change in
channels the techniques is that combines the routing and channel
allocation. In route discover phase common control channel use to
broadcast the route updating in the routing table in this protocol
best path selection is based on sequence number. In C-DSDV channel
switching is used to improve the system performances. If there are
more primary users routing over head will be increased

Cognitive
Ad-Hoc On-demand Distance Vector (C-AODV) Protocol
Cognitive
Ad-Hoc On-demand Distance Vector (C-AODV) Protocol is based on AODV a
wireless network protocol it is designed according to avoid primary
users activates regains for routing formation and packet discovery.
It gives the minimized route cost by forwarding packets through joint
path and channel selection at each node it takes the advantage of
availability of multiple channels to improve the overall
performances.

SER-Spectrum
and Energy Aware Routing Protocol
SER
is an on demand routing protocol which provide high throughput in
multi-hop networks it selects energy efficient route and assign
channels and timeslots for connection request. The communication
segment assignment algorithm is used for balances traffic load among
the CR users. In route discovery phase it broadcasts Route Request
Messages to other nodes so it has routing overhead of RRE, RREP, RERR
and ROP messages.

GYMKHANA Protocol
GYMKHANA
is an on demand routing protocol and enhanced version of AODV used
the GYMKHANA algorithm using virtual graphs and evaluate the cost by
using Laplacian matrix. It has a secondary user’s self-interference
over head.

UNITED
NODE Protocol
UNITED
NODE Protocol is a distributed and efficient based interference aware
routing protocol. It incorporates the spectrum availability cost and
interference metrics into the routing algorithm to find better routes
between the nodes it repairs routes by using route preservation
method. It provides adaptability to the environment and increases
throughput and reduces data delivery latency.

DELAY-MINIMIZED
ROUTING PROTOCOLS FOR MOBILE COGNITIVE RADIO Ad-Hoc NETWORKS
ROPCORN
Protocol
ROPCORN
Protocol is the on demand routing protocol which was designed for
data transportation using link modeling and used to minimized delay
for a set of users in network. It broadcast the packets in link with
the low cast and no primary user is affects. ROPCORN is based on
RACON protocol it uses buffers in the intermediate nodes and forwards
the packets there is no overhead due to the use of spectrum
availability and load estimation, the optimal route selection is
based on spatial or temporal locality of link disconnection.

SEARCH
A Routing Protocol
It
is the on demand routing protocol and enhanced version of AODV which
is based on the geographic routing and follow the greedy forwarding
and PU avoidance for joint channel-path optimization algorithm to
find the best path. SEARCH undertakes both the path and selection to
avoid PU activity region and tries to maintain end-to-end latency it
has routing overhead due to the RRE, RREP, RERR and ROP messages.

Link
Prediction-Based Adaptive Routing

Link Prediction-Based Adaptive
Routing is based on link-availability prediction. The link
–availability prediction considers primary user activity and user
mobility. This routing reduces the energy consumption and gives least
delay by enhances network performance. It works based on link
prediction and topology control

Joint
Routing and Channel Assignment

Joint
Routing and Channel Assignment (JRCA) approach
based on delay prediction and a heuristic algorithm which used the
collision probability and Link
Stability
Prediction.
It is and on demand routing protocol which user AODV type of routing
with heuristic values and can find out the path with minimal
end-to-end (e2e) delay.

Adaptive
Delay Tolerant Routing Protocol (ADTRP)

The
ADTRP algorithm finds a stable sequence of instances of the mobile
graph and the communication topology of interest such that the number
of transitions from one instance of the topology to another in the
sequence is the global minimum. The algorithm uses the average
lifetime of the mobile graphs in the stable sequence for
communication topology and it is a generic for stable sequence of any
communication topology it uses the heuristic topology for routing so
it improved
throughput, better packet delivery ratio, decreased packet drop and
reduced delay.

STOD-RP:
A Spectrum-Tree Based On-Demand Routing Protocol

STOD-RP
is an on demand routing protocol which was designed for reduces the
control overhead and average end-t-end delay minimization and it is
an extension of the original Ad-hoc On-demand Distance Vector (AODV)
protocol which uses spectrum tree addresses, spectrum decision and
route selection in an efficient way for this route matrix is used.
Fast and efficient spectrum-adaptive route recovery method is used
when path is damaged.

CONCLUSION
In
routing
is challenging issues in cognitive networks and it is very
challenging in mobile cognitive networks due to the node mobility
primary user interface and spectrum scarcity this paper conclude that
every protocol is designed for overcome certain problem in networks
one is for multiple problems and one is for single problem like
improving performance, minimized end-to-end delay, overall throughput
increasing and so on. There is a for more protocols or improved
versions of protocols for increasing problems and recruitments. In
further work on this paper a delay minimized routing protocol is
proposed and implemented that improved version protocol in NS3 will
be presented.