## 6 Conclusions  
Within the NANs, applications present unique QoS requirements based on their traffic characteristics. However, in conventional OLSR protocols, routing decisions are based on a single metric, and all traffic types are forwarded on the same link irrespective of individual traffic requirements. By employing multiple metrics and integrating AHP into the routing decision process, the \(OSLR_{MM}\) technique retrofits QoS in OLSR to improve network delay and reliability. The results from the NAN topologies investigated reveal that \(OSLR_{MM}\) improved the performance of AMI traffic in terms of reliability and delay compared with conventional single-metric OLSR protocols. For example, in a 25-node WMN-based NAN, we showed that \(OSLR_{MM}\) can improve the end-to-end delay and PDR by 23% and 45%, respectively, compared with conventional OLSR variants that are based on a single metric. Beyond the scenarios presented, the proposed technique is generally suitable for AMIs with heterogeneous wireless technologies or non-uniformly distributed loads on intermediary links  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Application Traffic Type** & **ETX** & **ML** & **MD** & \(OLSR_{MM}\) & **Best Performance** \\ \hline EV (PDR) & 50.06 & 32.5 & 30.1 & 57.5 & \(OLSR_{MM}\) \\ Meter reading (PDR) & 47.8 & 30.04 & 29.13 & 58.67 & \(OLSR_{MM}\) \\ Power quality (PDR) & 47.8 & 29.8 & 27.94 & 86.65 & \(OLSR_{MM}\) \\ DR (PDR) & 67.3 & 39.4 & 37.7 & 91.4 & \(OLSR_{MM}\) \\ Cumulative (PDR) & 50.358 & 32.522 & 30.886 & 73.5265 & \(OLSR_{MM}\) \\ Cumulative average delay (ms) & 1040.1 & 957.07 & 1718.7 & 729.5 & \(OLSR_{MM}\) \\ \hline \hline \end{tabular}
\end{table}
Table 5: Summary of the simulation results for the NAN grid cluster.  
between smart meters and the data concentrator. To facilitate the practical realisation of the proposed technique, future work will include the impact of OLSR probes on the performance and implementation complexity of \(OSLR_{MM}\). Furthermore, QoS routing protocols such as HQMR, QUORUM and MARIA will be another focus of our future research, which can give insightful results when compared to the schemes studied in the current work.  
The authors would like to acknowledge the financial support of the European Regional Development Fund (ERDF) through the Centre for Global Eco-Innovation, Lancaster University and HW communications Ltd Lancaster, UK.  
All four authors contributed to the paper. [PERSON] conceived of and designed the model. All of the other authors wrote, reviewed and commented on the manuscript. All of the authors have read and approved the final manuscript.  
The authors declare no conflict of interest.  
The following abbreviations are used in this manuscript:  
\begin{tabular}{l l} AHP & Analytical Hierarchy Process \\ OLSR & Optimised Link State Routing Protocol \\ ETX & Expected Transmission Count \\ ML & Minimum Loss \\ MD & Minimum Delay \\ RLMT & Relative Link Metric Type \\ RLMV & Relative Link Metric Value \\ RLMTW & Relative Link Metric Weight \\ AMI & Advanced Metering Infrastructure \\ SG & Smart Grid \\ WMN & Wireless Mesh Network \\ PDR & Packet Delivery Ratio \\ MCDM & Multi-Criteria Decision-Making \\ EV & Electronic Vehicle \\ \end{tabular}