OPTIMAL CONFIGURATION OF NETWORK CODING IN AD HOC NETWORKS

OPTIMAL CONFIGURATION OF NETWORK CODING IN AD HOC NETWORKS

Abstract

•  In this paper, we analyze the impact of network coding (NC) configuration on the performance of ad hoc networks with the consideration of two significant factors, namely, the throughput loss  and the decoding loss, which are jointly treated as the overhead of NC.

•  In particular, physical-layer NC and random linear NC are adopted in static and mobile ad hoc networks

(MANETs), respectively.

•  Furthermore, we characterize the goodput and delay/goodput tradeoff in static networks, which are also analyzed in MANETs for different mobility models (i.e., the random independent and identically distributed (i.i.d.) mobility model and the  random  walk model) and transmission  schemes (i.e., the  two-hop relay scheme and the flooding scheme).

•   Moreover, the optimal configuration of NC, which consists of the data size, generation size, and NC Galois

field, is derived to optimize the delay/ goodput tradeoff and goodput.

Existing System

•  In the last few years, significant efforts have been devoted to designing schemes adopting NC, aiming at full utilization of network resources in applications such as wireless ad hoc networks, peer-to-peer networks, etc. An important work by Liu et al.

•  introduced  the  observation  that  only  a  constant  factor  of  throughput improvement       can  be brought about to k-dimensional random static networks.

•  Further works by Zhang et al. analyzed the delay, throughput (including the overhead of NC), and their     tradeoff in    fast           and          slow      mobility     models    for          mobile           ad             hoc        networks   (MANETs)               by employing random linear NC (RLNC).

•  It  was  indicated  in  their  results  that  order  improvement  of  throughput  scaling  laws  can  be achieved by adopting RLNC in MANETs.

Disadvantages

•  Do not carry any valuable data

Proposed System

•  When  considering  the  given  two  factors,  the  traditional  definition  of  throughput                                                                                                                    in  ad  hoc networks is no longer appropriate since it does not consider the bits of NC coefficients and the linearly correlated packets that do not carry any valuable data.

•  Instead, the goodput and the delay/goodput tradeoff are investigated in this paper, which only take into account the successfully decoded data.

•  Although there were some works focusing on throughput loss and decoding loss, in some other

networks, their impact on scaling laws in ad hoc networks is still a challenging question.

•  Moreover, if we treat the data size of each packet, the generation size (the number of packets that are combined by NC as a group), and the NC coefficient Galois field as the configuration of NC, it is necessary to find the scaling laws of the optimal configuration for a given network model and transmission scheme.

Advantages

•  Consider the throughput loss and decoding loss

•  Improve the data efficiency

Network

Coding

Block Diagram

Two significant factors

Throughput loss

Decoding loss

Good put and delay/good put tradeofff

Analyzed in

MANETs

Conclusion

•  In this paper, we have analyzed the NC configuration in both static and mobile ad hoc networks to optimize the delay/goodput tradeoff and the goodput with the consideration of the throughput loss and decoding loss of NC.

•  These results reveal the impact of network scale on the NC system, which has not been studied in previous works.

•  Moreover, we also compared the performance with the corresponding networks without NC.

•  The results indicate that NC provides improvement on goodput in mobile networks but no gain on delay/goodput  tradeoff  in  all  of  the proposed  models  and  schemes,  except  for the flooding scheme in the i.i.d. mobility model.