# Design and Analysis of a Low Latency Deterministic Network MAC for Wireless Sensor Networks
## 2 Related Works
A comprehensive analysis of energy consumption of body area networks including the effect of packet inter-arrival time are given in [20]. However, the work did not consider retransmissions within the current superframe. To enhance the reliability of the LLDN networks, the authors in [21] propose one retransmission scheme for the time-varying channels by choosing the best relay node through the reinforcement-learning method. A new MAC protocol is proposed in [22] to minimize the energy consumption in WSN, where the authors have not considered the transmission failure due to the channel error. To avoid external interference, different frequency adoption schemes are proposed in [23]. A priority-based adaptive time slot allocation method isproposed in [24] based on the IEEE 802.15.4 MAC protocol. However, they have not considered the transmission failure nodes. The stability of the WSNs in terms of throughput is analyzed in [25] considering the exponential backoff scheme. However, the work is based on the IEEE 802.15.4 MAC mechanism. Collisions normally occur when the number of nodes increases in the network. To avoid the energy consumption due to collisions and to enhance the throughput of the network, the authors in [26] have proposed one collision-free MAC mechanism. However, they have not considered the retransmission opportunity for the transmission failure nodes. The hidden node problem increases the number of retransmissions in the network such that the battery lifetime of nodes is affected. Imperfect channel sensing is also one of the causes to significantly affect the network performance. To avoid the hidden node collisions, a new protocol is proposed in [27] by using carrier sense multiple access with collision notification (CSMA/CN) to approximate carrier sense multiple access with collision detection (CSMA/CD) for the wireless network. In this work, the authors use two antennas to emulate full duplex mode so that collision notifications can be allowed to broadcast, and the ongoing transmissions can be aborted. The use of transmission power control can help to address industrial issues concerning energy consumption, interference and fading. In [28], an adaptive multi-channel transmission power control algorithm for industrial wireless networks such as WirelessHART, ISA 100.11a has been designed RSSI. However, when a transmitted packet is not acknowledged properly, it needs to be retransmitted at the cost of additional energy and delay. Besides, the authors did not consider the transmission failure due to channel error and the retransmission opportunity in the current superframe to avoid the delay. A Markov model is designed in [29] to analyze the throughput of the IEEE 802.15.4 network with the presence of hidden nodes. Almost all existing analytical models assume ideal channel conditions. However, in real-world scenarios, wireless channels exhibit burst errors. A three-dimensional Markov chain model is proposed in [30], which is applied to analyze the network performance under burst channel errors. Comparative studies between IEEE 802.15.4e LLDN and IEEE 802.15.4 slotted CSMA/CA have been analyzed in [31] under the ideal channel condition, which is not realistic. In [32], the authors evaluate the impact of losing synchronization under the beacon-enabled star topology of the IEEE 802.15.4 network. To avoid collisions in a dense network, a new variable CCA MAC protocol for WSNs is designed and the performance analyzed in [33]. However, this protocol needs a significant amount of energy, which is the major constraint for sensors. From the current literature survey, we noticed that most works are based on the performance analysis of the IEEE 802.15.4 standard. To the best of our knowledge, the performance of LLDN has not been analyzed yet, which has many applications in home, healthcare and industry automation. In this paper, we not only propose a new channel access mechanism to avoid the collision due to simultaneous transmissions, but also design one CSMA/CA mechanism for the shared slots of LLDN superframes.