A Comparative Analysis between Forwarding and Network Coding
Techniques for Multiple Wireless Networks
Carleton University,
Ontario, Canada. February 2011.
Broadcasting is used as a building block in many MANET (Mobile Ad hoc
Network) routing protocols. In addition, broadcasting is a key primitive in ad
hoc networks to support group-based applications. Efficiently supporting
broadcasting in multihop wireless networks is therefore important. In this
paper, we compare ef-ficient broadcasting protocols
based on packet forwarding with those based on network coding. Using a number
of network scenarios, we derive lower bounds for the required number of packet
retransmissions at the MAC layer to support broadcast with and without applying
network coding techniques. We compare these lower bounds with each other, as
well as with protocols proposed for each approach. More specifically, we use
SMF and PDP as sample forwarding-based broadcast protocols, and a simple
XOR-based coding protocol over SMF and PDP as representative network coding
solution. The results show that neither packet forwarding protocols nor network
coding protocols achieve the theoretical lower bounds, in particular as the size
of the network area (at constant density) increases. The comparison of the
lower bounds also shows that network coding does have a potential performance
advantage over packet forwarding solutions for broad-casting in multi-hop
wireless networks, in particular for larger fixed density networks, justifying
its inherent increased complexity.