QoS-aware MAC protocols for wireless sensor networks: A survey <s> QoS perspectives in WSNs <s> In this paper, we assess the state of the art of Quality of Services (QoS) support in wireless sensor networks (WSNs). Unlike traditional end-to-end multimedia applications, many non-end-to-end mission-critical applications envisioned for WSNs have brought forward new QoS requirements on the network. Further, unique characteristics of WSNs, such as extremely resource-constrained sensors, large-scale random deployment, and novel data-centric communication protocols, pose unprecedented challenges in the area of QoS support in WSNs. Thus, we first review the techniques for QoS support in traditional networks, analyze new QoS requirements in WSNs from a wide variety of applications classified by data delivery models, and propose some non-end-to-end collective QoS parameters. Next, the challenges of QoS support in this new paradigm are presented. Finally, we comment on current research efforts and identify many exciting open issues in order to stimulate more research interest in this largely unexplored area. Keywords— Wireless networks, wireless sensor networks, QoS, collective QoS <s> BIB001 </s> QoS-aware MAC protocols for wireless sensor networks: A survey <s> QoS perspectives in WSNs <s> In this paper, we study a randomized scheduling algorithm, and analyze the problem of maximizing network lifetime under quality of service constraints such as bounded values of detection delay, detection probability, and network coverage intensity in wireless sensor networks. We show that the optimal solutions exist and provide the conditions of the existence of the optimal solutions. <s> BIB002 </s> QoS-aware MAC protocols for wireless sensor networks: A survey <s> QoS perspectives in WSNs <s> Wireless Sensor Networks are composed of autonomous interconnected sensing devices. Power limitation is considered as the most significant constraint for sensors. It directly influences the sensors ' lifetime and hence the application quality of service. Many studies have been conducted in the field, where different power-based routing and data gathering strategies are proposed. However, most of them are driven for specific applications and for specific network topologies. In this paper, we propose a power-and-QoS-based framework for heterogeneous sensor networks. This framework is formulated as an optimization problem. It aims at maximizing the application lifetime while ensuring acceptable level of quality of service. Moreover, the proposed framework is designed for a general network architecture where both clustered and hierarchical structures can coexist. The framework simultaneously optimizes intra-cluster transmissions and inter-cluster multi-hop routing. <s> BIB003 </s> QoS-aware MAC protocols for wireless sensor networks: A survey <s> QoS perspectives in WSNs <s> It has been a challenging problem to support target coverage with QoS requirements in wireless sensor networks, because we need to consider both energy constraint and so-called target Q-coverage requirement, i.e. different targets may require different sensing quality in terms of the number of transducers, data sampling rate, etc. First we prove that this problem is NP- complete, then we formulate the optimization using Linear Programming techniques, however, directly solving this optimization seems desperately complex due to the combinatorial complexity. Thus a column generation based approach is developed to solve this problem by decomposing the original problem into a master problem as well as a corresponding sub problem and solves them iteratively. Numerical results are given to verify our approach and gain some insights into the performance aspects in designing such surveillance systems. <s> BIB004 </s> QoS-aware MAC protocols for wireless sensor networks: A survey <s> QoS perspectives in WSNs <s> In wireless sensor networks (WSNs), QoS topology control achieves energy-efficiency by turning off redundant nodes and links, while still satisfying the given QoS requirement. However, existing topology control algorithms assume that links are either connected or disconnected. Recent experiments have shown that, besides the connected and disconnected region, a large percentage of links reside in the transitional region with fluctuating link qualities. In this paper, we propose both centralized and distributed solutions for QoS topology control, where we employ the opportunistic transmission to catch the best transmission opportunities on transitional links. Our simulations demonstrate that opportunistic transmission based approach can significantly improve energy-efficiency in QoS topology control with low communication overhead. A unique contribution of this paper is to consider link quality and apply opportunistic communication in topology control for WSNs. <s> BIB005 </s> QoS-aware MAC protocols for wireless sensor networks: A survey <s> QoS perspectives in WSNs <s> Energy limitation is one of the most important characters in Wireless Sensor Networks(WSNs). Using energy efficiently is significant to prolong sensor network lifetime. The more repeated overlay is, the more energy is wasted. If we divide the nodes into some independent subsets and alternatively awake these subsets, the node energy is consumed slowly. However, the requirement of QoS is opposite to the ennergy. To solve this problem, the relationship between the desired QoS requirement and the minimum number of active nodes is analyzed in the randomly deployed sensor networks. We propose a Topology Controlling QoS(TCQS) Protocol for wireless sensor networks based on our analytical results. According to the energy and previous working status, our scheme selects the minimum number of active nodes without using any location information. Simulation results show that TCQS can not only reduce the energy consumption of nodes and increase the network lifetime, but also balance the energy consumption among nodes. <s> BIB006
QoS perspective actually defines the aspect of QoS which we are interested. In an earlier work BIB001 , Chen et al. classified the QoS perspectives in WSNs into two categories as Application-specific and Network-specific. These two perspectives represent the two different approaches already followed in the literature: Application-specific perspective: Application-specific perspective focuses on the quality of the application itself. QoS is again assured by fulfilling the requirements imposed by the application such as lifetime BIB002 BIB003 , coverage BIB004 , deployment, quality of the sensing, camera resolution, number of active sensors BIB006 BIB005 . Network-specific perspective: Network-specific perspective provides service quality during delivery of the data by the communication network. From this perspective, network resources are utilized efficiently in each layer of the communication protocol stack to fulfill the requirements imposed by the carried data, such as latency, packet loss, reliability. In this paper, since our focus is on QoS-aware MAC protocols, we will be approaching from the network-specific perspective to QoS provisioning and hence, applicationspecific perspective will be out of our scope in this work. The reader can refer to BIB001 BIB002 BIB003 BIB004 BIB006 BIB005 for the applicationspecific approaches.