Design and implementation of enhanced IEEE 802.15.4 for supporting multimedia service in Wireless Sensor Networks

Recently, there has been a growing demand to incorporate multimedia content delivery over the Wireless Sensor Networks (WSNs). This feature could not only enhance several existing applications in the commercial, industrial, and medical domains, but could also spur an array of new applications. However, the efficient gathering of still images, audio, and video information in WSNs imposes stringent requirements on the throughput and energy consumption. Most wireless communication standards with high or moderate data throughputs do not focus primarily on energy efficiency. The IEEE 802.15.4 WPAN standard provides a widely accepted solution for low-cost and low-power wireless communication, with a potential to cater to many types of application scenarios. IEEE 802.15.4 MAC includes features such as its dual operational modes (Non-Beacon-enabled mode/Beacon-enabled mode), which make this standard more attractive for providing multimedia services over the networked sensors. Its Beacon-enabled mode can conserve energy by using the RF sleep mechanism, but it is limited by the lower data throughput. On the other hand, the Non-Beacon-enabled mode can offer higher data throughput but at the expense of significant energy consumption, mainly due to the idle listening problem. In order to overcome these issues, we propose an enhancement to IEEE 802.15.4, named TEA-15.4, which adaptively adjusts the active period based on traffic information. To detect data traffic in the network, the proposed scheme utilizes two techniques: Arbitrary Traffic Signal (ATS) and Traffic Time-Out (TTO). By utilizing these two techniques, the proposed TEA-15.4 can not only support enough data throughput to carry out multimedia communications, but also offer lower energy consumption for the sensing device in WSNs. For performance evaluations, we implement our proposed scheme and the IEEE 802.15.4 full-standard on the TinyOS. Based on the results gathered from testbed experiments and the TOSSIM simulator, TEA-15.4 is shown to be a suitable mechanism for Wireless Multimedia Sensor Networks (WMSNs).