TDMA implementation for simultaneous signal acquisition of machine condition in wireless sensor networks

Abstract

Wireless sensors, installed on machinery, and Time Division Multiple Access (TDMA) transmission make an ideal system for monitoring machine conditions in industrial plants because there is no need for electronic wiring. However, field application of such a system, capable of continuously transmitting data over 100 Hz sample rates, has not been successful so far. In this research, a TDMA network protocol capable of acquiring data from multiple sensors with over 100 Hz sample rates was developed for field application. The protocol was implemented in a single cluster-star topology network and the system was evaluated by node number and transmission distance. The network simulator-2 (ns-2) is used for real field simulation. The cases of non-TDMA and TDMA protocol are compared with four sensor nodes. In the case of a 20-second transmission time, there is little difference between the reception rates of non-TDMA and those of TDMA system. However, the difference was much greater when using a 60-second transmission time.

On the Energy/Distortion Tradeoff in the IoT

“…We focus on the design of the Medium Access Control (MAC) layer, which has a strong impact on the energy efficiency, since the usage of the RF chain may be very energy-demanding [17]. Although random access is sometimes preferred over coordinated access [18], [19], TDMA-based schemes have proved to be a valid choice in IoT contexts [20], [21]. Contention-based protocols are flexible and require low synchronization costs, but generally lead to a high energy wastage due to collisions and idle listening, which can be instead avoided in reservation-based protocols, at the cost of some additional synchronization overhead [22].…”

A MAC Protocol Based on Broadcast Messages for Wireless Sensor Network

“…Scheduling MAC protocols generally use TDMA mechanism, which has the following characteristics, the continuous time is divided into a series of consecutive time slots, nodes are awakened only in scheduled time slot to send and receive data packets [5]. TRAMA is a traffic-adaptive scheduling MAC protocol.…”