International Journal of Research in Engineering, Science and Management Volume-1, Issue-10, October-2018 www.ijresm.com | ISSN (Online): 2581-5782 1 Abstract—Subsequent to introduction of Wireless Sensor Networks (WSNs) it remain an active research topic due to their wide variety applications in areas such as healthcare, military, monitoring, surveillance and many more systems. In most applications, sensor nodes are inhibited in energy supply and communication bandwidth. Therefore, novel techniques to reduce energy inefficiencies and for efficient use of the limited bandwidth resources are essential. Such constraints combined with intense network operation create several challenges to the design and management of WSNs and require energy-consciousness at all layers of the networking protocol stack. For example at the Data- Link layer, low duty cycle Medium Access Control (MAC) protocols trade off latency for energy efficient operation. In this paper, we present a survey of modern low duty cycle MAC protocols. We first summarize the design challenges for MAC protocols in WSNs. Then, we present a widespread survey of the most important and recent MAC protocols. These protocols are classified into synchronous and asynchronous based on their mode of operation. Finally, the paper emphasizes open research problems in MAC layer for WSNs. Index Terms—Wireless Sensor Networks; Linear Sensor Networks; Chain-type sensor networks; Duty-cycle; MAC protocols. I. INTRODUCTION The wireless sensor network (WSN) is a well-proven advanced technology that aims to expand human-oriented applications in large-scale remote sensing. Such networks are used in various applications to provide accurate estimates where the presence of a person is complex, dangerous and / or costly. This technology can be implemented to monitor large- scale environments such as international border surveillance; tracing of railways, detection of leaks in gas / oil / water pipelines, search and rescue from natural disasters, flood warning systems, etc. All these applications have a common topological structure that is internally linear. This is the result of a carefully controlled and planned deployment of sensor nodes for careful monitoring of a controlled environment, which is linear in nature. We consider this class of networks as WSN linear or LWSN. Alternatively, in some studies this WSN class was called WSN-type. Linear / chain network properties represent a number of special problems and new design requirements that need to be addressed. The purpose of this study is to examine the relevant MAC protocols that apply the work cycle function that can be used / modified to meet the needs of LWSN applications. In the next section, new problems related to the linear structure of the network are discussed with respect to the MAC protocols. Then in Section III, we'll look at the MAC protocols of the work cycle, which are classified as synchronous and asynchronous. In this review, we evaluate the suitability of these protocols for LWSN. We define optimization methods for your work to solve special properties of LWSN. We also determine their common strengths and weaknesses with respect to classic WSNs. In Section IV we present our main findings related to the development of a new MAC protocol specific for LWSN [1]. Section V concludes the document and highlights future directions of research. II. CHALLENGES CAUSED BY LWSNS Providing end-to-end communication with low cost with an acceptable delay in the delivery of data is the main objective of WSN. These problems are reinforced in LWSN, since the linear topology limits the number of neighbors and, consequently, a possible transmission route, which makes data loss more likely than in classic WSNs. Typically, LWSNs suffer from unbalanced data traffic between nodes, for example, nodes closest to the sink are usually more congested than nodes further down. This is due to the use of the multi-hop approach, which is used to transfer data from nodes that cannot directly reach the receiver. As a result of the failure in the data transmission, the data is significantly increased due to congestion and increased communication delays due to frequent retransmissions [2]. Uneven load distribution across the network becomes more evident during the life of the network. The nodes closest to the shell suffer from more energy depletion than the nodes furthest from the shell. In this case, the network can be terminated prematurely due to disconnection of communication lines with the receiver [3]. In addition, to ensure continuous communication and a small communication delay, nodes around the receiver cannot sleep often or for a long time and must be available to perform their relay functions [3]. In LWSN, node failure has serious implications for the overall functionality of the network in terms of network coverage and connectivity. In classic networks, the redundancy MAC Protocols for Application-Specific Wireless Sensor Networks: A Study Harish Joshi 1 , Ravindra Eklarker 2 1 Research Scholar, Dept. of Elec. and Comm. Engg., Guru Nanak Dev Engg. College, Bidar, India 2 Professor and Head, Dept. of Elec. and Comm. Engg., Guru Nanak Dev Engg. College, Bidar, India