In the present scenario, the term wireless body area network (WBAN) is becoming an integral part of human day to day life due its wide variety of applications, especially in the field of healthcare systems. To design such a reliable body area network system, there are a number of factors to be considered both in hardware and software levels. One of such factors still developing is the design and the analysis of routing protocols in the network layer. Routing protocols are a set of protocols which can identify and maintain the routes in the network so that the data can be exchanged between the nodes efficiently. Hence, routing protocol plays a vital role in the wireless sensor networks for reliable communication between the sensor nodes. In this paper, different routing protocols for body area networks are surveyed and observed that they are affected by factors like energy, network topology, various quality of services (QoS) in the nodes, node temperature, transmission range of nodes, human posture, etc. An evocative taxonomy of protocols is presented such as cluster-based, cross-layered, postural movement based, QoS aware and temperature-aware routing protocols. From the survey, it is found that the selection of a routing protocol is application dependent. For example, the energy efficient protocols like reinforcement learning based routing with QoS support or wireless autonomous spanning tree protocol can be used for daily health monitoring systems due to its high packet delivery ratio. If the system is for in vivo networks, routing algorithm for network of homogeneous and Id-less biomedical sensor nodes or mobility-supporting adaptive threshold-based Thermal-aware energy-efficient multi-hop protocols are the suitable ones. For critical and emergency cases, where accuracy with little delay is the major concern, the protocols like critical data routing, reliability aware routing, data-centric multi objective QoS-aware routing protocol, etc. can be rightly chosen. This entire survey paper can be used by the researchers as a reference for studying various WBAN routing protocols, especially in the field of medical health care systems.

With the advancement in networking, information and communication technologies, wireless body area networks (WBANs) are becoming more popular in the field of medical and non-medical applications. Real-time patient monitoring applications generate periodic data in a short time period. In the case of life-critical applications, the data may be bursty. Hence the system needs a reliable energy efficient communication technique which has a limited delay. In such cases the fixed time slot assignment in medium access control standards results in low system performance. This paper deals with a dynamic time slot allocation scheme in a fog-assisted network for a real-time remote patient monitoring system. Fog computing is an extended version of the cloud computing paradigm, which is suitable for reliable, delay-sensitive life-critical applications. In addition, to enhance the performance of the network, an energy-efficient minimum cost parent selection algorithm has been proposed for routing data packets. The dynamic time slot allocation uses fuzzy logic with input variables as energy ratio, buffer ratio, and packet arrival rate. Dynamic slot allocation eliminates the time slot wastage, excess delay in the network and attributes a high level of reliability to the network with maximum channel utilization. The efficacy of the proposed scheme is proved in terms of packet delivery ratio, average end to end delay, and average energy consumption when compared with the conventional IEEE 802.15.4 standard and the tele-medicine protocol.

Wireless sensor networks (WSNs) are collection of sensor nodes that co-operate together to monitor an environment or a system. These sensor nodes works on limited battery source, one of the factor to be consider while designing a WSNs protocol is by efficient use of available energy resources to prolong network lifetime. Studies show that one of the efficient WSNs protocol is Low Energy Adaptive Cluster Hierarchy (LEACH). To modify LEACH protocol much more energy efficient, few improvements such as election of Cluster Head, assigning TDMA (Time division multiple access) slot to Cluster Members and multi hop for long distance communication were done. In this paper we propose Modified LEACH protocol for small network areas and Modified Multi hop LEACH protocol for large network areas. Simulation on LEACH, Modified LEACH and Modified Multi-hop LEACH protocol are done. Results shows that Modified LEACH have better network lifetime than LEACH protocol.

Wireless Body Sensor Networks (WBSNs) are exposed to interferences such as intrabody and interbody interferences. Intrabody interference exists within a WBSN and interbody interference occurs between the WBSNs, which degrades the overall system performance. The impact of interference becomes more intense with the increase in the number of nodes. The most popular standard for WBSNs, the IEEE 802.15.4 standard, is very well suited for short-range communication and low-power wireless sensor networks. However, this standard is not robust enough to handle the interferences when multiple nodes/WBSNs come in close to each other. In this paper, a new scheme that can mitigate the effect of interference called the Interference Reduction Channel Access Mechanism (IR-CAM) is proposed. In this mechanism, the coordinator adjusts the contention window size and frame length adaptively to reduce the effect of interference. Simulations are carried out for both static and mobile nodes. The simulation results prove the efficacy of the new scheme by comparing with the existing schemes in terms of normalized throughput, average end-to-end delay, average energy consumption, packet drop rate, and packet delivery ratio. In static, the proposed method outperforms the IEEE 802.15.4e standard and the Transmission Model by 33% and 10% in terms of throughput and a 3% drop in the average end-to-end delay when compared to the IEEE 802.15.4e standard. In mobility, the proposed method has 53% and 27% reduction in average energy consumption when compared to the IEEE 802.15.4e and Transmission model. The simulation also includes the performance analysis for multiple WBSNs.

IEEE 802.15.4/ZigBee Wireless sensor networks are now becoming popular due to rapid increase in the number of very small, integrated low-powered sensors and mobile devices capable of gathering critical, real-time information for remote surveillance, environmental monitoring, distributed target tracking etc. ZigBee is the only IEEE standard uniquely designed for low-power, a low-cost, low-data rate based wireless technology network, that provides network security, and application support services operating on top of the IEEE 802.15.4 Medium Access Control (MAC) and Physical (PHY) Layer wireless standard[1]. The survey on IEEE 802.15.4/ZigBee sensor networks showed that the unreliability is the major limitation of such sensor networks, which is termed as MAC unreliability problem. The studies also highlighted that, this unreliability problem is due to the default MAC parameter settings suggested by the standard itself. Different solutions have come up to improve the reliability problem, such as setting a predefined value for parameters which is suitable only for static conditions, an adaptive technique for dynamic conditions based on mathematical model etc. In this proposed work, the impact of MAC parameters on packet delivery ratio and the effectiveness of ADAPT algorithm is analyzed for a ZigBee sensor network. A comparative study of ZigBee network with and without ADAPT is carried out based on simulated results obtained from NS2, which is an object oriented network simulating tool. As a modification, signature verification of each node on the sensor network is performed for security purposes.

Mobile adhoc networks (MANETs) or simply adhoc network, comprises of nodes that freely and dynamically self - organize into arbitrary and temporary network topology without any infrastructure support. Each node in a MANET are free to move in any direction, and will therefore change its links to other devices frequently. Due to the limitation of signal transmission range, not all nodes can directly communicate with each other. There comes the importance of routing protocols. Many routing protocols are being developed now a days. One of the new reactive, on-demand routing protocol DYMO is discussed here. DYMO is Dynamic MANET On-demand routing protocol, is one of the newly intended routing protocol used by mobile nodes in wireless networks. It is a successor to AODV routing protocol. Here in this paper we are enhancing the performance of DYMO routing protocol by considering the energy and traffic parameters of the network. Also we are comparing En-DYMO with existing DYMO and AODV routing protocols in terms of average throughput and packet delivery ratio.