DATA LINK QUALITY SCHEME FOR
ODMRP IN MANETs
Kanwalpreet Kaur Sandeep Singh Kang
M .Tech (CSE) Asst. Proff C.E.C Landran (Mohali) C.E.C Landran (Mohali) [email protected] [email protected]
ABSTRACT: Mobile Ad Hoc networks (MANET) is a large groups of wireless networks that have well established application ranges. Despite the fact that they address very distinctive groups of devices. The
group-oriented services are one of the primary application classes that are addressed by mobile ad hoc networks
(MANETs) in recent years. Discovering and maintaining routes between nodes are one of the biggest challenges
in MANETs the ultimate goal of the MANET community is to provide a set of standardized protocols that can
be both robust and scalable. To improve the group oriented services we use a multicast stability scheme. In this
paper we propose a data link quality scheme (link stability) for ODMRP . The multicast mesh is constructed by
using route request and route reply packets with the help of multicast routing information cache and link
stability database maintained at every node. The stable paths are found based on selection of stable forwarding
nodes that have high stability of link connectivity. The link stability is computed by using the parameters such
as received power, distance between neighboring nodes and the link quality assessed using bit errors in a packet.
Index Terms: MANET forwarding node, routing information cache, link stability database, multicast routing, stable
INTRODUCTION:
A mobile adhoc network is a kind of self configuring network connected by wireless links. . With the rapid
growth of group communication services, the routing in MANET has attracted a lot of attention recently. It is
highly dynamic network having no pre-established infrastructure forming a on-demand network and the
nodes are free to move randomly. Thus the network topology can changed rapidly. Due to the dynamic nature of
network topology, the various constrained occur and cause for many challenges in MANET. There is bandwidth
constrained, energy constrained, capacity links constrained and for all these MANETS need a efficient ways to
determine network organization, link scheduling and routing protocols. The routing protocols for adhoc
networks have been distributed as proactive and reactive routing protocols. Proactive is one of old way of
routing in mobile adhoc networks. The protocols under proactive maintains a consistent overview of network.
These protocols uses tables to store information about the nodes in network and on base of that information the
data is transferred among the various nodes in network. Destination Sequence Distance Vector routing protocol
(DSDV), Wireless Routing Protocol (WRP) and Cluster-head Gateway Switch Routing (CGSR) are some of the
popular table-driven protocols for mobile ad-hoc networks. Reactive protocols are on-demand protocols in
which route is established only when there is some data to transfer. To establish a route from source to
destination or an intermediate node has a route to the destination. Some of the better known on-demand
protocols are Ad-hoc On-demand Distance Vector routing (AODV), Dynamic Source Routing (DSR), Dynamic
MANET On-demand(DYMO), Location Aided Routing Protocol (LAR) and Temporary Ordered Routing
Algorithm (TORA).The data link quality scheme can be measured by link stability. The stability of a link is
given by its probability to persist for a certain time span, which is not necessarily linked with its probability to
reach a very high age [1].For link quality various factors can be measured and one main factor is antenna range.
Every node in a network will be assigned a antenna range to make contact with its neighbors. Each antenna have
its energy level and with the help of antenna range the path from source to destination is find. After finding the
route from source to destination, the data is transferred and energy level consumed is be measured. Finally the
multiples routes for destination is checked for comparing of their throughputs. The PDR is one of most
important metrics that we should consider in link stability.
RELATED WORK:
In the recent period lot of research has been done on MANETS based on multicasting. The multicasting is one
of methods that because of group-oriented computing are mostly used in MANET routing [3]. Lately, the
upcoming concerns is link stability in various routing protocol and for this the ad-hoc routing protocol is to
prefer stable links than transient links. The work in the context of link stability is the development of
Associativity Based Routing (ABR) [6].In this a link is considered to be stable if it exists for a time of at least
Athresh= 2rtx/v, where rtx the transmission range and v denotes the relative speed of two devices [1]. Signal
Stability Adaptive Routing (SSA) [5] follows a similar approach. It distinguishes strongly connected from
weakly connected links where a link is considered to be strongly connected, if it has been active for a certain
predefined amount of time.
In ODMRP there is only one path to forward packets and if path fails due to dynamic nature of network nodes,
the packet is lost and routing process ha sto be started again. Then research on multipath is done. The various
methods have been there to find a multipath and Route diversity is also applied on multipath [3]. Previous
studies showed that mesh-based protocols are robust against topology change and are more suitable than
tree-based protocols [10]. ODMRP is an ad hoc multicast routing protocol tree-based on a multicast mesh [9]. There are
many extended version on ODMRP; in [11] we explained the reliable ODMRP. In [12] we describe the local
recovery approach and QoS method base on ODMRP and we attempted to support the Qos and relaibility on
ODMRP.
As per the literature survey, it is observed that multicast routing protocols performed well in packet delivery
ratio, control overhead. ODMRP is one of multicast routing protocol which gives better results in above defined
metrics. Thus, the performance of ODMRP can be increased by having stable links during data transfer. PROBLEM ISSUE:
Nodes in Mobile Adhoc networks are battery driven and they suffer from the problem of limited energy level.
The large part of energy in this network is consumed when there is link breakage during transfer of data packet
and the process again starts for maintaining a link after link breakage. To overcome this problem, the data link
data to receiver nodes and vice versa. In this paper we implement the data link quality scheme in ODMRP and it
shows that it performed well when stability scheme is implemented on ODMRP.
ON DEMAND MULTICAST ROUTING PROTOCOL (ODMRP):
ODMRP is mesh based routing protocol and uses the concept of forwarding group. In this only a subset of nodes
will be allowed to forward a multicast packets. In this protocol multiple routes are established and updated by
source on demand. In this a source node broadcast a JOIN-QUERY if it does not have any route to send its data
packet. This JOIN-QUERY periodically broadcasted to refresh the membership information and update routes.
When an intermediate node receives a join-query, it stores the source ID and sequence no in its message cache
to detect any duplicates. When the join-query packet reach a multicast receiver, it creates and broadcast a
JOIN-REPLY to its neighbors. When a node receive a join-reply, it checks whether the next hop node ID of one the
entries matches its own id or not. If it does, the node realizes that it is on the path to source and thus it is part of
forwarding group.
DATA QUALITY SCHEME FOR ODMRP: ODMRP is a based on multicast mesh and for creation of stable routes in multicast mesh various control packets such as route request, route reply and route error (RE) packets
are used. In ODMRP when link stability is to be implemented the route request has following database:
1) Source Address: It is the address of source node which is originating the packet.
2) Sequence Number: It is assigned to every packet for identifying the packet.
3) Route request flag (RR flag): This flag is set for the duration of forward travel of RR packet from
source to destination.
4) Power: This is the power at which a node has transmitted the packet to neighbor.
• 5) Antenna gain: This is gain of antenna at the forwarding node to forward RR packet to
its neighbor.
When the ODMRP is implemented in which it calculates the link stability, it has following algorithm for Route
Request Phase:
1) Source node S broadcast packet to find the route for two multicast receiver R1 and R2.
2) Nodes A,B and C receive RR packet from S. The node update the paths to S in its memory cache by
using next hop as S.
3) It also updates link stability database and stability factor.
4) Node A broadcast RR packet to its neighboring node and to R1. Similarly, B and C broadcast to R2,R1
and its neighbors.
5) If any of neighboring node find that packet it receive is duplicate, it discard that packet.
6) R1 and R2 update memory cache and link stability database.
7) Now, the R1 and R2 have a path from source node S.
The steps for Route Reply In ODMRP when link stability is to be implemented:
1) R1 broadcasts RP packet to source S through A and B.
2) Nodes A and B receives RP packet from R1. These nodes update the path to R1 in its memory cache.
4) Node A compares the next hope address in memory cache with the next hop address of RP packet and
if match found , it set flag status.
5) Now, S has path from R1 and R2 that is R1-A-S, R1-B-S
QUALITY SCHEME DATABASE:
When a multicast mesh is created in ODMRP and to create stable paths in mesh from source to multicast
destination, there is following parameters which to be calculated for better results and some database points are
also following:
1) Node ID: It stores the neighbor node ID.
2) Power level: Whenever a packet (either RR or RP packet) is received from its neighbor, this field
stores the ratio (Pwij ) of measured value of the power received (Pr) at the node to the power
transmitted (Pt) by neighbor node.
3) Distance: This field stores the distance between the neighboring nodes. The distance is computed by
using the free space propagation model [7] [8] given in equation 1.
Pr(d) = Pt Gt Gr λ/(4π)d2 L equation 1
where Gt and Gr are the antenna gains of the transmitter and the receiver, respectively. L is the system loss, λ is
the wavelength and d is the distance between two MANET nodes.
4) Stability factor: It is the value computed for a link to a neighbor based on the power level, distance and
link quality. Stability factor Sij of a link between nodes i and j is defined by equation 2.
Sij = [Pwij * Qij /dij] equation 2
where Pwij , qij and dij are the signal strength, link quality and the distance between nodes i and j, respectively.
5) Link quality: This field stores the value of the link quality of neighboring nodes. It is approximated by
ratio of the number of bits in error to the number of bits received (bit error rate). This value gets
updated for every packet received at a node over a certain period.
SFN selection among all forwarding nodes in the mesh is an important process since it helps in establishing
stable path from receivers to source or vice versa among many alternate paths already found. A forwarding
node checks for higher value of stability factor Sij in its MRIC for next hops corresponding to group id /
destination address. Forwarding Node selects one of the next hops as SFN using equation 3,
SFN = max NEXTHOPi(S) (3)
CONCLUSION:
The above mentioned data quality scheme considers link stability. This scheme is expected to provide highly
stable, reliable, robust paths .As the paths in this should be stable for longer time and does not break easily
during data transfer so this can also give longer battery life. It also improves the packet delivery ratio and
decrease the control overhead. In Future work this technique can be implemented in some tree based protocol
like ADMR and the comparison of ODMRP and ADMR can be done.
REFRENCES:
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applications Vol No: 02 Issue:02,page 555-561 (2010)
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