Random Linear Network Coding (RLNC) is considered to be one of the promised
solutions to achieve the reliability of transmission in multi hop wireless networks, Since it
is based on correcting the loss of the packets in the medium through the conti
nuity of
transmitting coded packets from each segment until receiving acknowledgment of getting
the required number of these packets for decoding. However, because of the nature of
wireless medium and multi hops transfer, a loss or delay of the ACK may occur, which
causes transmitting extra packets and time delay to the next segments, consequently
decreasing the throughput of these networks.
In this research, we propose a new transmission mechanism for reliable transfer in
multi hops wireless networks through using the concepts of sliding window and fast
retransmit with RLNC, for transmitting packets of consequent segments in specific
continues flow and fast correcting the loss in these segments. Simulation results show that
proposed mechanism decreases the time delay for transmission process and increases the
transfer throughput of these networks.
Multi hop wireless networks face many challenges basically the
limitation of bandwidth, loss of packets because of many problems
in wireless medium also loss of paths because of the random and
unpredictable movement of wireless nodes, which reduce
the
performance of these networks. Recently, Network coding has been
used as promising technology that achieves the reliable transfer of
data in wireless networks with high throughput. Considering the
efficiency of this technology and with benefiting from both the
same cost paths and the broadcasting property of wireless medium,
a multi transmission mechanism for random linear network coding
has been proposed in multi hop wireless networks, which depends
on multicasting of coded packets on the same cost paths.
Wireless networks suffer from frequent loss of packets for many reasons such as
interference, collision and fading. This makes wireless medium unreliable medium for data
transfer. The main methods for ensuring the reliability in this medium are usi
ng
transmission control protocol (TCP) and the automatic repeat request (ARQ). Recently,
network coding has been found as new technology that changes the traditional forwarding
method (Store- and- Forward) in the networks to more effective and intelligent method
(Code- and- Forward), which contributes to the increase of both capacity and throughput of
these networks.
In this research, random linear network coding is used as promising technology that
aims to achieve the reliable transfer of data in losing wireless networks, and studying the
enhancement that this technology presents to the performance of these networks in unicast
and multicast transmission. For evaluating the efficiency of this technology and comparing
its performance with the performance of reliable transfer protocols, we use the networks
simulator (NS3). Simulation results showed that random linear network coding achieve the
reliable transfer of data with bigger throughput and less delay and number of transmission
compared with the protocols (TCP, ARQ).
