# Opportunities and Challenges for Error Control Schemes for Wireless Sensor Networks: A Review
## 5 Review on ECS Methods on WSN
### Other Techniques  
In this chapter, we briefly mention other techniques used in error correction in WSN. However, we are only reviewing BICM techniques used in WSN error correction. Network coding is utilised in error correction and energy saving in [95; 96]. Finally, residual numbering is utilised in error correction and energy saving in [97]. We introduce BICM techniques in Section 2.5 and the researchers evaluate the use of this technique in WSN for performance and energy analysis [98; 99; 100; 101]. In [98], [PERSON] et al. consider the use of \begin{table}
\begin{tabular}{p{56.9 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Ref (Yr)** & **ECS(s) and Adaptive Parameter(s)** & **Network** & **Results** \\ \hline
[56] (010) & Convolutional code and encoder memory order & Modified multi-hop WSN model & Normalised energy consumption and optimal memory order for specific SNR. \\ \hline
[88] (010) & ARQ, HARQ and selecting among ARQ or HARQ according to distance & Single-hop network & Energy efficiency comparison \\ \hline
[89] (010) & BCH and code rate (version) & Single-hop network & Experimental result of version change \\ \hline
[94] (011) & Adaptive hybrid BCH code & Multi-hop network & Expected energy consumption and latency analysis \\ \hline
[90] (012) & Adaption framework & Single-hop network & Standalone BER results \\ \hline
[91] & BCH code with code rate variation depending on CSI and ACK & Single-hop network & Energy efficiency result versus communication distance for BCH and adaptive error correcting code \\ \hline
[93] & Adaptive chase-2 decoding for BCH code & Multi-hop network & Decoding energy consumption for BCH code with standard chase and adaptive chase \\ \hline
[92] (016) & LDPC code and code rate & Single-hop network & Standalone BER results \\ \hline
[35] (017) & LDPC, ARQ and selection of ECS on CRC output and distance & Multi-hop network & Total energy versus network lifetime \\ \hline
[37] (017) & LDPC, RS and selecting among RS and LDPC depending on distance & Multi-hop network & Total energy and number of nodes alive versus round \\ \hline \hline \end{tabular}
\end{table} 
Table 4: A summary of adaptive ECS for WSN. BICM technique in WSN where the authors use Hamming, LDPC, convolutional code as FEC, chaotic Baker map as interleaver and multi-carrier modulation as modulation technique. The paper presents standalone BER analysis of BICM techniques without considering WSN scenario. As expected, the use of the BICM technique enhances BER of WSN communications, but there is no energy analysis for the proposed BICM. Therefore, the suitability of the proposed BICM technique cannot be justified in an energy constrained WSN scenario. [PERSON] et al. perform analysis of BICM in industrial WSN setting in [101].In this experiment, the authors use RS code as FEC with bit and symbol interleaving. However, the type of interleaving and modulation techniques used in the experiment are not clearly explained. The paper concludes that there is no significant improvement on packet salvation ratio (performance measure) by using interleaving in multipath fading environments. The paper also did not present energy analysis of the proposed BICM technique. RS code is used in the proposed BICM technique and the code has simple encoding decoding techniques. Therefore, the results presented on the paper can be justified even though there is no energy analysis result available. [PERSON] and [PERSON] presented BICM techniques using regular LDPC code with 61-QAM and AWGN channel considering an SHAS network [99]. The paper presented an energy consumption model without considering decoding cost, which is valid as we discussed in Section 4.1. In addition, this paper presented optimal constellation size and transmit energy versus distance between nodes for various block lengths. Those results are supported by information theoretic analysis. However, there is no explanation regarding what type of decoding algorithm is used for LDPC decoding. In [100], [PERSON] et al.