## 2 Overview of Existing Wireless Standards and Protocols  
This section presents an overview of the wireless technologies that have been specifically tailored for use in industrial automation. They can be categorized into two parts, the IEEE 802.15.1 and IEEE 802.15.4 [4] based standards. Wireless Interface for Sensor and Actuators (WISA) [5] is a protocol based on the IEEE 802.15.1 standard. It has been developed by ABB and allows wireless communication between sensors and actuators. It is specifically designed to address the stringent real-time requirements of factory automation. ZigBee Pro [6], WirelessHART [7], WIA-PA [8], ISA100.11a [9], and IEEE 802.15.4e [10] (Time Slotted Channel Hopping (TSCH) mode) are the IEEE 802.15.4 based standards. Among these, WirelessHART, WIA-PA, ISA100.11a and IEEE 802.15.4e are designed for industrial process automation requirements using concepts derived from the Time Synchronized Mesh Protocol (TSMP) [11]. TSMP, developed by DustNetworks, is a media access and networking protocol that is designed for low power and low bandwidth reliable communication. The WirelessHART protocol, developed by the HART Communication Foundation, uses a time-synchronized, self-organizing and self-healing mesh architecture. WirelessHART is backward compatible with the HART (Highway Addressable Remote Transducer) protocol, which is a global standard for sending and receiving digital information over analog wires between monitoring and control systems. WIA-PA is a kind of system architecture and communication protocol of wireless networks that was first developed by the Chinese Industrial Wireless Alliance (CIWA). \begin{table}
\begin{tabular}{|c|c|c|c|c|c|c|c|c|} \hline \begin{table}
\begin{tabular}{|c|c|c|c|c|c|c|c|} \hline
**Item** & \multicolumn{2}{c|}{**Protocols**} & \multicolumn{4}{c|}{**Standards**} \\ \cline{2-7}  & **TSMP** & **802.15.4e** & **WISA** & **ZigBlec Pro** & **WirelessHART** & **WIA-PA** & **ISA100.11a** \\ \hline Data Link & Network-wide time & Time Sloted & TDMA, Channel & CSMA/CA, Beacon & TSDP features, & CSMA/CA, & TSDP features, \\ Layer & synchronization, channel & Channel Hopping & Hopping & Sync., GTS, & Superframe & TDMA, and & CSMA/CA (In SH \\  & hopping, Channel & (TSCH) or TSNP, & Frequency Agility & Optimization, no & FDMA. & period), Channel \\  & Blacklisting, Graph and & MAC amendment to & & & frequency reuse for & Channel Hopping (SH, FH, \\  & source routing, dedicated & the existing standard & & dedicated links & (AFH, AFS, and & Hybrid), AFH and \\  & slotted unicast & 802.15.4-2006 & & & & TH) & Blacklisting, \\  & communication & & & & & Superframe \\  & bandwidth, link-layer & & & & & Optimization \\  & ACKs, concurrent link & & & & & Optimization \\  & activation, and omitting & & & & & Optimization \\  & the poor method for & & & & & Optimization \\  & speech such as sending & & & & & \\  & Beacon & & & & & \\ \hline Physical & Compatible with multi- & IEEE 802.15.4, 2.4 & IEEE 802.15.1, 2.4 & IEEE 802.15.4, 2.4 GHz, & IEEE 802.15.4, 2.4 & IEEE 802.15.4, 2.4 & IEEE 802.15.4, 2.4 \\ Layer & channel standard such as the & GHz, DSSS (Direct- & GHz, Data rate 1 Mb/s & 868 MHz, 915 MHz, & GHz, DSSS (Direct- & GHz, DSSS (Direct- \\  & the IEEE 802.15.4 2006 & Sequence Spread & DSSS (Direct- & Sequence Spread & (Direct- \\  & standard & Spectrum), Data rate & & Spread Spectrum), Data rate & Spread Spectrum), Data rate \\  & & 250 Kb/s & & rate 250 Kb/s & 250 Kb/s & Data rate 250 Kb/s & 250 Kb/s \\ \hline System & Centralized (Coordinates & Centralized \& & & Distributed & Centralized \& & Centralized \& \\ Management & the communication & Distributed & & & Distributed & Distributed & Distributed \\  & schedule for the network & & & & & (The routing \\  & and finding the routes) & & & & & devices, serving as \\  & & & & & & & cluster heads, \\  & & & & & & implement the task \\  & & & & & & of an agent of the \\  & & & & & & network manager) \\ \hline \end{tabular}
\end{table} 
Table 1: _Cont._