Network coding is a collection of techniques in which a node is allowed to combine, encode and send one or more packets as a single encoded packet instead of sending individually. It improves throughput, packet delivery ratio and efficiency of the system. The inherent broadcasting nature of wireless mediums helps us to adopt network coding very easily. At the same time, as it reduces the number of transmissions, it reduces the probability of various losses due to transmission impairments, channel contentions and route failures. This paper discusses various well known network coding schemes.. Network coding is broadly classified into global and local network coding. Network coding is also classified into binary -Xor based and random linear coding based network coding. Further to these, based upon the applications, Network coding schemes are classified for unicast, multicast and broadcast applications. In each of these categories, network coding is explained in the reference of inter-session network coding and intra-session network coding.

Network coding is a way of improving performance in wireless networks by combining two or more packets to send together as a single packet. Two or more packets are combined together to form a single packet. the main goal of using network coding is to reduce bandwidth requirement. Wireless networks often suffer from various issues like collision, transmission errors etc due to broadcasting of signals. Network coding helps in reducing such issues and improving performance significantly. Various network coding schemes are implemented at physical layer, data link layer and network layer. This research paper introduces a novel network coding scheme TCP-NC -TCP with Network Coding at transport layer. TCP's most widely deployed variant -TCP NewReno is used. Simulation is performed in NS 2.35. Scenario based wireless multihop networks are designed with different scenarios based on number of nodes, number of hopes and type of network(poor or congested). TCP-NC shows a significant amount of improvement when used with the poor network.