## 3 Interoperable M2M  
Several M2M solutions have been developed to serve a specific business application, which resulted in a dispersion of the technical solutions [40, 41]. As a consequence, current M2M markets are highly segmented and often rely on proprietary solutions. But for M2M communications meet the expectations of new business and revenue opportunities while reducing maintenance and resource costs [20], future  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Contributions** & **Reference** \\ \hline Human-based _vs._ M2M Communications & [PERSON] _et al._[21], [PERSON] _et al._[17] \\ \hline Technical Challenges & [PERSON] _et al._[25], [PERSON] _et al._[12], [PERSON] [15], [PERSON] _et al._[21] \\ \hline Requirements & [PERSON] _et al._[22], [PERSON] _et al._[12], [PERSON] _et al._[21] \\ \hline \multirow{4}{*}{Applications} & Healthcare & [PERSON] [15], [PERSON] [38], [PERSON] _et al._[26], [PERSON] _et al._[13], [PERSON] _et al._[39] \\ \cline{2-3}  & Vehicles & [PERSON] _et al._[37] \\ \cline{2-3}  & Airlines & [PERSON] _et al._[34] \\ \hline \multirow{2}{*}{Proformance Evaluation} & [PERSON] _et al._[37], [PERSON] _et al._[35], [PERSON] _et al._[36] \\ \cline{2-3}  & QoS provision & [PERSON] _et al._[26] \\ \cline{2-3}  & Throughput & [PERSON] _et al._[26] \\ \cline{2-3}  & Interference & [PERSON] _et al._[27] \\ \hline \multirow{4}{*}{Channel Access} & Access Delay & [PERSON] _et al._[30], [PERSON] _et al._[23] \\ \cline{2-3}  & Energy Efficiency & [PERSON] _et al._[23] \\ \cline{2-3}  & Latency & [PERSON] _et al._[29] \\ \cline{2-3}  & QoS provision & [PERSON] _et al._[12] \\ \cline{2-3}  & Delay & [PERSON] _et al._[32] \\ \cline{2-3}  & Power Consumption & [PERSON] _et al._[33] \\ \cline{2-3} \cline{2-3}  & Delay & [PERSON] _et al._[31] \\ \cline{2-3}  & Packet Collisions & [PERSON] _et al._[24] \\ \cline{2-3}  & Throughput & [PERSON] _et al._[31] \\ \hline \multicolumn{2}{c}{Mobile M2M Gateway} & [PERSON] _et al._[25], [PERSON] _et al._[12] \\ \hline \hline \end{tabular}
\end{table}
Table 1: Summary of survey of literature and challenges presented in the document.  
M2M markets need to be based on industry standards to achieve explosive growth [25]. Additional deployment obstacles include lack of market awareness, technology complexity, initial deployment cost, operator complexity, and operator return on investment concerns [20].  
To enable interoperability between M2M services and networks, the European Telecommunications Standards Institute (ETSI) established in 2009 a Technical Committee (TC) focusing on M2M Service level. There are two other reference architectures for M2M: the 3 rd Generation Partnership Project (3 GPP) - Machine Type Communications (MTC) and IEEE 802.16p M2M, focus in enhancing access and core networks, respectively. These two architectures are complementary to ETSI M2M, and therefore it is possible to combine ETSI M2M architecture with either, resulting in a cellular-centric M2M service architecture [42]. To avoid worldwide market fragmentation and reduce standardization overlap, the oneM2M Partnership Project [43] was created in July 2012 to develop one globally agreed upon M2M specification, initially focusing on consolidating M2M Service Layer standard activities into oneM2M [44]. Most of its current specifications are based on the ETSI M2M Service Layer, therefore we focus on ETSI M2M perspective in the next section.