# A Novel IEEE 802.15.4e DSME MAC for Wireless Sensor Networks
## 2 Related Works  
Many channel access schemes have been proposed to enhance IEEE 802.15.4 performance for different performance parameters like throughput, delay, reliability, and energy consumption. A generalized approach to analyze the performance of the slotted CSMA/CA scheme in the IEEE 802.15.4 standard is designed in [3]. Authors in [4] present an analytical model for the MAC scheme of IEEE 802.15.4 to predict the energy consumption as well as the throughput of the saturated and unsaturated traffic rates. A Markov chain based analytical model is introduced in [5] to evaluate the impact of throughput and energy consumption on the probability of delivering a packet. An integrated cross-layer model of the MAC and physical layers for unslotted IEEE 802.15.4 networks is presented in [6] by considering explicit effects of multi-path shadow fading channels in the presence of interferers. In an event driven application, all the associated devices start transmitting data simultaneously in non beacon enabled wireless sensor network. Reference [7] provides an accurate performance analysis for event-driven CSMA/CA WSNs. Authors in [8,9] have designed the time critical services and priority based adaptive MAC schemes for the WSNs. However, these schemes do not talk how to increase reliability of the network. An analytical model based on a Markov chain for the GTS allocation scheme in the contention-free period (CFP) is presented in [10]. Authors in [11,12] have designed the GTS allocation scheme based on the data size and mobility of the devices for an optimal utilization of the channel bandwidth. In a wireless network due to some hardware failure, devices associated with particular application start sending faulty data. Again limited link capacity forces the devices to send the quantized data. Under such scenario to enhance the reliability authors in [13] propose a multiple superframe structure and a non-preemptive GTS scheduling algorithm. In a wireless network, devices synchronously alternate active and sleep modes and completely turnoff the radio during sleep mode. Authors in [14] provide comprehensive review synchronous MAC schemes with respect to latency. However, authors in these papers have not considered the retransmission opportunity for the transmission failure during GTS. A significant amount of packet loss occurs due to interference, which degrades the expected performance in wireless network. To avoid Wi-Fi interference among the devices in a network, devices should use orthogonal channels. However, limited number of orthogonal channels are available. Hence, authors in [15] propose one frequency agility based interference avoidance algorithm that detects the interference and devices switch to the safe channel adaptively. Authors in [16] perform theoretical analysis of throughput for WSNs under external interference with deployment of forward error correction. Also, authors in [17] have studied different types of interferences, direction of signal arrival and attenuation losses associated with smart building environment. However, none of the works has considered the reliability of the data communications. An analytic model is designed in [18] to study the MAC performance and reliability. Energy is a major constraint for device and the major energy consumption of device is due to transmission. As channels are considered with temporal and fixed path loss values in body area networks, authors in [19] have suggested through experimental results that transmitting in \(-12\) dBm to \(-15\) dBm is suitable for energy efficient body area networks. A comprehensive analysis of energy consumption of body area networks including the effect of packet inter-arrival time is given in [20]. Using the neighbors information regarding packet size, data interval, energy and consumed bandwidth, a new MAC scheme is proposed in [21] to minimize the energy consumption in wireless sensor network. Authors in [22] propose a priority-based adaptive time slot allocation scheme for the IEEE 802.15.4 MAC scheme.