Nour Kadi

Optimized MPR-based flooding in wireless ad hoc network using network coding

Multipoint relays ldquoMPRrdquo have been introduced in the proactive protocol OLSR in order to optimize the flooding overhead of control traffic. In this paper we propose an algorithm to optimize the MPR-based flooding by using network coding where MPR nodes do not simply forward packets they overhear but may send out information that is coded over the contents of several packets they received. Our interest is to reduce the number of transmissions. We show by simulation that flooding can be efficiently performed by exploiting network coding with multipoint relays, resulting in significant reductions in the number of transmissions in the network. We can get benefits from this approach also in other practical considerations such as restricted complexity and memory capabilities.

MPR-based flooding with distributed fountain network coding

This paper describes DiFCod, a protocol which is designed to reduce the number of transmissions required for flooding in wireless ad-hoc networks using network coding. We propose a simple distributed coding scheme which can be applied locally at each node. The efficiency of network coding is further enhanced by applying multiple point relays (MPR). The simulation results shows that flooding can be efficiently performed with DiFCode. Using a theoretical analysis, we show that DiFCode ensures that any packet generated at any node is delivered to the entire network with high probability.

Fountain Codes with XOR of Encoded Packets for Broadcasting and Source Independent Backbone in Multi-Hop Networks Using Network Coding

We consider multiple source asynchronous broadcasting problem. That is, in each broadcast, one of the nodes is the source, and the message is to be received, unaltered, by all the other nodes in the network. We propose to exploit LT code, which is one of the fountain codes, with the source independent backbone in order to reduce the number of transmissions for broadcasting with network coding in ad hoc wireless network. We use the principle of LT code to perform network coding in a simple distributed manner where encoding can be applied with both received singletons and non-singletons, and generated candidates can be used in an optimization criteria. We show by simulation that our approach reduces the number of transmissions required for flooding.

New degree distribution to improve LT-code in network coding for broadcasting in ad-hoc wireless networks

In this paper, we present a novel rateless code which outperforms LT-code, since it is adapted for network coding. To reduce the delay incurred at the intermediate nodes because of decoding and re-encoding, we design and analyze a novel degree distribution which we call Switched Distribution. This distribution increases the delivery ratio at the decoder even when few encoded symbols are received. The performance of our scheme is evaluated using simulations.

Network coding for MPR-based flooding in ad hoc wireless networks under mobility conditions

We propose a novel distributed coding scheme for broadcast over mobile ad hoc networks. In this scheme, we combine MPR technique with network coding. Only multipoint relay (MPR) nodes perform coding using a rateless code. Rather than waiting for a large number of encoded packets to be received before MPR nodes could decode and resend coded packets, we design a new degree distribution that enables the nodes to start decoding even when small number of encoded packets are received. Thus, we decrease the delay introduced at the intermediate nodes. The main advantage of using a rateless code for encoding instead of using a random linear combination of the previously received packets is to reduce significantly the encoding and decoding complexities. We provide a performance evaluation using a simulation to demonstrate the efficiency of our code even under mobility condition.

Distributed switched code (DiSC): a distributed rateless code for broadcast in ad-hoc wireless networks

We propose a novel distributed coding scheme for broadcast over ad-hoc wireless networks. In this scheme, all nodes perform coding using a simple rateless code over the previously received, generated, or decoded symbols. Rather than waiting for a full block of encoded packets to be received before intermediate nodes could decode and resend coded packets, we design a new degree distribution that enables the intermediate nodes to start decoding even when small number of encoded packets are received. Thus, we decrease the delay introduced at the intermediate nodes because of decoding and then re-encoding. The main advantage of using a kind of rateless code for encoding instead of using a random linear combination of the previously received packets is to reduce significantly the encoding and decoding complexities. We provide a performance evaluation using a simulation to demonstrate the efficiency of our code in term of reducing the number of transmissions and increasing the delivery ratio.