Enhancing energy efficiency of IEEE 802.15.4- based industrial wireless sensor networks

The IEEE 802.15.4 standard protocol has been widely used in many industrial wireless sensor networks (IWSN), due to its low energy, optimal data rate and relative long-distance characteristics. The protocol operation, however, should be optimized to maximize efficiency and minimize interference between wireless sensor network (WSN) nodes. The protocol supports two media access modes: carrier sense multiple access (CSMA) and time division multiple access (TDMA). In this paper, we use the enhancing energy efficiency of wireless sensor networks (EEE-WSN) protocol that alternates between these two modes. The objective is to accommodate for traffic load and to produce better efficiency. EEE-WSN utilizes CSMA in the case of having lightweight traffic, which is normally the case when having normal and non-critical events in the area of interest (AoI). It switches operation in case of heavy traffic load conditions, which often happen when a critical event is detected. Furthermore, a modified selective activation (SA) technique is used to minimize the energy consumption and to reduce the interference between redundant nodes. The protocol has been implemented using Qualnet simulator and its performance has been evaluated for different simulation time, packet rate ratios, and sent packets. The simulation results showed that the EEE-WSN outperformed the IEEE 802.15.4 while operated in either CSMA or TDMA by decreasing the energy consumption by around 1%. The amount of energy saving is exponentially increasing as a function of the simulation time. The EEE-WSN has lower end-to-end delay by 0.4, 0.1 s under light traffic conditions when compared with IEEE 802.15.4- TDMA, and IEEE 802.15.4-CSMA modes, respectively. At heavy traffic conditions, the EEE- WSN has similar end-to-end delay to IEEE 802.15.4- TDMA, and less end-to-end delay values by 0.3 s when compared to IEEE 802.15.4- CSMA. Although IEEE 802.15.4- TDAM has lower packet loss values by 5% when compared to EEE-WSN under light traffic conditions and similar loss at heavy traffic conditions, EEE-WSN still has lower packet loss values by 5% and 25% when compared to IEEE 802.15. 4- CSMA, under light and heavy traffic conditions, respectively.