Nowadays, the needs of healthcare for the elderly are growing rapidly. To provide continuous all-day medical monitoring and diagnoses at low cost, wireless body area networks (WBANs) have become a forward-looking technology since it is regarded as a potential solution for the remote collecting of physical and symptoms information. Because of its application characteristics, reliability and delay are the most important, as the energy consumption also needs to be considered. However, due to the limitation of the large propagation loss and the complicated channel conditions, the existing routing algorithms cannot completely address the above problems. To balance the node energy consumption and reduce the transmission delay, a simplified energy-balanced alternative-aware routing algorithm (SEAR) for WBANs is proposed in this paper. The residual energy and the current load of a candidate of the next hop destination are considered during the routing request forwarding procedures. The required information is exchanged during the improved routing request and routing request response procedures, and the routing cost is modified accordingly. To improve the compatibility and robustness, the added path is introduced as an alternative path in our algorithm. The simulation results show that SEAR achieves significantly higher network residual energy and network throughput, and end-to-end delay is also reduced. Therefore, the lifetime of the network is extended effectively.INDEX TERMS Wireless body area networks (WBANs), routing request, residual energy, routing algorithm, simplified, NS2.

Wireless body area networks (WBANs) are composed of several tiny sensor devices which are embedded on or implanted in the human body. They are designed to continuously transmit sensed physiological data and act as key infrastructures for remote healthcare monitoring and treatment. Considering the limited power supply, varying link connectivity, and complicated channel environment, the design of routing protocol in WBANs is challenging. The existing algorithms cannot fully satisfy the application requirements. Focusing on lower energy consumption, a directional diffusion routing protocol for WBANs is proposed in this paper. The concept of the gradient is introduced to indicate the direction and the rate of data transmission and the minimum hop count in directed diffusion is used as the criterion for establishing the gradient. Each node is required to maintain the gradient information of its neighbor nodes with the shortest path. Simultaneously, the residual energy is also considered to further improve the performance. The simulation results show that the proposed protocol has significantly lower packet loss rate and power consumption in both static and mobile scenarios. The reliability of the data transmission is improved and the networks life is extended effectively.

This paper proposes an enhanced transport layer protocol for precise flow control in data centers, referred to as PFDCT, combining explicit rate control (priority scheduling) and implicit rate control (marking algorithm with dynamic threshold) innovatively, while satisfying the transmission requirements of each data flow. It enables multiple data flows to share the bandwidth fairly, which is rarely achieved by previous data transmission protocols. Our design stems from the observation that different packets in a data center network need to be processed differentially and that the accuracy of the feedback of the indication information to the link state will directly affect the effectiveness of the congestion control mechanism. Our tests show that PFDCT has lower network jitter, better fairness, and significant performance gains over existing proposals (DCTCP, ICTCP, and L2DCT) in terms of Flow Completion Time (FCT) and throughput on average. Furthermore, we discussed the impact of the marking algorithm with dynamic thresholds on the performance of PFDCT, and the results of the experiments show that the addition of the marking algorithm will further improve the performance of PFDCT in terms of packet loss rate, latency, and FCT.

No abstract