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Network Coding for Multihop Wireless Networks: Joint Random Linear Network Coding and Forward Error Correction with Interleaving for Multihop Wireless Networks
Optimising the throughput performance for wireless networks is one of the
challenging tasks in the objectives of communication engineering, since wireless
channels are prone to errors due to path losses, random noise, and fading
phenomena. The transmission errors will be worse in a multihop scenario due to its
accumulative effects. Network Coding (NC) is an elegant technique to improve the
throughput performance of a communication network. There is the fact that the bit
error rates over one modulation symbol of 16- and higher order- Quadrature
Amplitude Modulation (QAM) scheme follow a certain pattern. The Scattered
Random Network Coding (SRNC) system was proposed in the literature to exploit
the error pattern of 16-QAM by using bit-scattering to improve the throughput of
multihop network to which is being applied the Random Linear Network Coding
(RLNC). This thesis aims to improve further the SRNC system by using Forward
Error Correction (FEC) code; the proposed system is called Joint RLNC and FEC
with interleaving.
The first proposed system (System-I) uses Convolutional Code (CC) FEC. The
performances analysis of System-I with various CC rates of 1/2, 1/3, 1/4, 1/6, and
1/8 was carried out using the developed simulation tools in MATLAB and compared
to two benchmark systems: SRNC system (System-II) and RLNC system (System-
III). The second proposed system (System-IV) uses Reed-Solomon (RS) FEC
code. Performance evaluation of System IV was carried out and compared to three
systems; System-I with 1/2 CC rate, System-II, and System-III. All simulations were
carried out over three possible channel environments: 1) AWGN channel, 2) a
Rayleigh fading channel, and 3) a Rician fading channel, where both fading
channels are in series with the AWGN channel. The simulation results show that
the proposed system improves the SRNC system. How much improvement gain
can be achieved depends on the FEC type used and the channel environment.Indonesian Government and the University of Bradfor
Joint random linear network coding and convolutional code with interleaving for multihop wireless network
NoAbstract:
Error control techniques are designed to ensure reliable data transfer over unreliable communication channels that are frequently subjected to channel errors. In this paper, the effect of applying a convolution code to the Scattered Random Network Coding (SRNC) scheme over a multi-hop wireless channel was studied. An interleaver was implemented for bit scattering in the SRNC with the purpose of dividing the encoded data into protected blocks and vulnerable blocks to achieve error diversity in one modulation symbol while randomising errored bits in both blocks. By combining the interleaver with the convolution encoder, the network decoder in the receiver would have enough number of correctly received network coded blocks to perform the decoding process efficiently. Extensive simulations were carried out to study the performance of three systems: 1) SRNC with convolutional encoding, 2) SRNC; and 3) A system without convolutional encoding nor interleaving. Simulation results in terms of block error rate for a 2-hop wireless transmission scenario over an Additive White Gaussian Noise (AWGN) channel were presented. Results showed that the system with interleaving and convolutional code achieved better performance with coding gain of at least 1.29 dB and 2.08 dB on average when the block error rate is 0.01 when compared with system II and system III respectively