A Review of Protocol Implementations and Energy Efficient Cross-Layer Design for Wireless Body Area Networks <s> Application and MAC, Physical Layer Schemes <s> The performance of applications on mobile devices is affected by the device constraints of memory, processing power, battery life and the variations in the wireless network. The variations in the wireless network will be compounded in the next generation networks-3G and beyond-when the devices move across heterogeneous networks. To allow interoperability with the Internet, existing standard protocol stacks would be deployed in the new networks and mobile devices. However, these protocol stacks which are architected and implemented in a layered manner do not function efficiently in mobile wireless environments. Cross-layer feedback in the protocol stack would be useful to improve the efficiency of these protocol stacks. In this paper, we discuss the benefits of cross-layer feedback on the mobile device and present a representative survey. <s> BIB001 </s> A Review of Protocol Implementations and Energy Efficient Cross-Layer Design for Wireless Body Area Networks <s> Application and MAC, Physical Layer Schemes <s> Wireless Sensor Networks (WSN) are mainly characterized by dense deployment of sensor nodes which collectively transmit information about sensed events to the sink. Due to the spatial correlation between sensor nodes subject to observed events, it may not be necessary for every sensor node to transmit its data. This paper shows how the spatial correlation can be exploited on the Medium Access Control (MAC) layer. To the best of our knowledge, this is the first effort which exploits spatial correlation in WSN on the MAC layer. A theoretical framework is developed for transmission regulation of sensor nodes under a distortion constraint. It is shown that a sensor node can act as a representative node for several other sensor nodes observing the correlated data. Based on the theoretical framework, a distributed, spatial Correlation-based Collaborative Medium Access Control (CC-MAC) protocol is then designed which has two components: Event MAC (E-MAC) and Network MAC (N-MAC). E-MAC filters out the correlation in sensor records while N-MAC prioritizes the transmission of route-thru packets. Simulation results show that CC-MAC achieves high performance in terms energy, packet drop rate, and latency. <s> BIB002 </s> A Review of Protocol Implementations and Energy Efficient Cross-Layer Design for Wireless Body Area Networks <s> Application and MAC, Physical Layer Schemes <s> Unlike conventional computer networks such as office LANs or the Internet which can be used for a host of applications, wireless sensor networks are typically used for specific applications in mind. It is this fundamental difference combined with the fact that energy efficiency is of paramount importance in wireless sensor networks that a different approach needs to be taken when designing protocols. In this paper we first describe the main differences and benefits of the cross-layered techniques used for sensor networks over the traditional OSI layered approach used for conventional networks. We then give two examples which illustrate how we extend usual sensor network cross-layered optimization by going beyond just MAC-routing optimizations to optimizations between the application and the MAC layers. <s> BIB003 </s> A Review of Protocol Implementations and Energy Efficient Cross-Layer Design for Wireless Body Area Networks <s> Application and MAC, Physical Layer Schemes <s> In wireless sensor networks congestion occurs in intermediate nodes while data packets travel from source to sink. Congestion causes packet loss which in turn drastically decreases network performance and throughput As sensors are energy constraint so it is a decisive task to detect the congestion and congested regions in a network to perform congestion control. In addition to that different application i.e. real time and non-real time data in sensor network have different QoS (delay, link utilization, and packet loss) guarantee requirement In this paper we proposed a new QoS adaptive cross-layer approach to control the congestion and support QoS guarantee for different application data in sensor network. This approach maintains two congestion control algorithm to control namely short-term and long-term congestion. To ensure real time and non-real time data flow, hop-by-hop QoS aware scheduling and QoS distributed MAC Manager are considered. The experimental outputs of this work are able to show that proposed scheme gives guaranteed QoS for different application data and gives a noticeable performance in terms of energy analysis and lifetime of the network. <s> BIB004 </s> A Review of Protocol Implementations and Energy Efficient Cross-Layer Design for Wireless Body Area Networks <s> Application and MAC, Physical Layer Schemes <s> In this work, we propose an effective application layer solution for packet loss mitigation in the context of Body Sensor Networks (BSN) and healthcare telemetry. Packet losses occur due to many reasons including excessive path loss, interference from other wireless systems, handoffs, congestion, system loading, etc. A call for action is in order, as packet losses can have extremely adverse impact on many healthcare applications relying on BAN and WAN technologies. Our approach for packet loss mitigation is based on Compressed Sensing (CS), an emerging signal processing concept, wherein significantly fewer sensor measurements than that suggested by Shannon/Nyquist sampling theorem can be used to recover signals with arbitrarily fine resolution. We present simulation results demonstrating graceful degradation of performance with increasing packet loss rate. We also compare the proposed approach with retransmissions. The CS based packet loss mitigation approach was found to maintain up to 99% beat-detection accuracy at packet loss rates of 20%, with a constant latency of less than 2.5 seconds. <s> BIB005 </s> A Review of Protocol Implementations and Energy Efficient Cross-Layer Design for Wireless Body Area Networks <s> Application and MAC, Physical Layer Schemes <s> The fact that the IEEE 802.15.4 MAC does not fully satisfy the strict wireless body sensor network (BSN) requirements in healthcare systems highlights the need for the design and analysis of new scalable MAC solutions, which guarantee low power consumption to all specific sorts of body sensors and traffic loads. While taking the challenging healthcare requirements into account, this paper aims for the study of energy consumption in BSN scenarios. For that purpose, the IEEE 802.15.4 MAC limitations are first examined, and other potential MAC layer alternatives are further explored. Our intent is to introduce energy-aware radio activation polices into a high-performance distributed queuing medium access control (DQ-MAC) protocol and evaluate its energy-saving achievements, as a function of the network load and the packet length. To do so, a fundamental energy-efficiency theoretical analysis for DQ-MAC protocols is hereby for the first time provided. By means of computer simulations, its performance is validated using IEEE 802.15.4 MAC system parameters. <s> BIB006
Although there are numerous examples of cross-layer schemes involving the lower layers, generally, cross-layer solutions incorporating the application layer do not figure highly in the available literature. Many existing protocols operating at the application layer were designed for wired networks and do not perform optimally in the low power wireless context. Schemes that can perform application level adaptation based on information from lower layers could provide performance benefits in low power wireless networks. The application layer can communicate the applications' QoS needs, i.e., data reliability, delay tolerance and response time to other layers BIB001 . Additionally, information on channel conditions from the MAC/physical layers could be used by the application layer as part of a cross-layer solution to improve performance. Rahman et al. BIB004 developed an adaptive cross-layer mechanism to control congestion for real-and non-real time data flow to support QoS guarantees at the application layer. Priority was given to real time data in terms of delay and available link capacity. The scheme linked the QoS requirements at the application layer and the packet waiting time, collision resolution and packet transmission time metrics at the MAC layer. Correlation-based Collaborative MAC (CC-MAC) protocol BIB002 is a cross-layer solution incorporating the application and MAC layers. CC-MAC exploits the spatial correlation between nodes to reduce energy consumption without compromising the estimated reliability achieved at the sink. Experiments showed that CC-MAC delivered improved performance over S-MAC and T-MAC in terms of energy efficiency, packet drop rate, and latency. In their work on a new energy saving MAC model, Otal et al. BIB006 developed a cross-layer solution incorporating a fuzzy rule scheduling algorithm and radio activation policy. The researchers present Distributed Queuing Body Area Network (DQBAN) MAC as an enhancement to 802.15.4 for a BSN that extends the research carried out by Lin and Campbell  . The research incorporates a fuzzy rule scheduler that optimizes the MAC layer to improve overall performance in terms of QoS and energy consumption. The protocol considered the node cross-layer constraints such as physical layer signal quality (SNR), system waiting time, and residual battery life to allocate slots within a superframe structure. Simulations covering homogeneous and heterogeneous scenarios demonstrated that DQBAN MAC can achieve higher reliabilities when compared to 802.15.4 whilst delivering specific latency demands and battery limitations. As part of research that focused on the benefits of cross-layer optimization between application and MAC layers, Chatterjea and Havinga BIB003 illustrated how two examples of an adaptive MAC could benefit in exchanging information with the application layer. To solve the problems of rapidly draining power sources and congestion in the network, the research exploited the high degree of spatial correlation that exists between the readings of adjacent nodes in a densely deployed network by utilizing a distributed and self organizing scheduling algorithm. The scheduling algorithm prevented two adjacent nodes acting as correlating nodes simultaneously and increased the robustness and accuracy of the data by giving every node a chance to act as a correlating node. Although simulations showed energy savings of up to 42% when using the cross-layer information, the researchers recognized that disturbances in the lower layers could have a detrimental effect on the upper layers. In particular, changes in link quality may lead to a reduction in the efficiency of the algorithm owing to the continuous rearranging of the scheduling scheme. This highlights the need for the upper layers to be adequately insulated from the instability of the lower layers. Gaudadri and Baheti BIB005 proposed an application and MAC cross-layer solution for packet loss mitigation for WBANs using CS based on ECG signals. The work addressed the issues of end-to-end packet losses due to excessive path loss, interference, handoffs, congestion, and system load. It was observed that when the signal contains redundancies, the packet losses can be treated as lossy compression performed by the channel. Lost packets are identified at the application layer via a sequence number field in the packet header of the lower layers. The research observed that reconstruction accuracy degrades gracefully as packet loss rate increases. ECG signals can be recovered with high fidelity even in high packet loss conditions with 99% heartbeat detection accuracy at packet loss rates of 20% with a constant latency of less than 2.5 s.