Network selection in cognitive radio enabled Wireless Body Area Networks

In recent years, the great interest in Wireless Body Area Networks (WBANs) has been aroused significantly due to the advancement in wireless communications. In wireless communication, all WBAN nodes that monitor the human body's vital functions transfer information to a central sink node, which is directly connected to a Cognitive Radio enabled Controller called CRC. To transfer this information from a CRC to an e-health server, it requires long-range wireless networks, such as UMTS, LTE, WiMAX, WiFi, and satellite internet provider. It is challenging for a CRC to select the best networks for different WBAN data traffic, such as emergency mandatory, delay sensitive, and general monitoring. This paper proposes a scheme for selecting the best network from the available networks depending on the Quality of Service(QoS) requirements for different WBAN applications. Different multiple attribute decision-making algorithms are used in the proposed scheme. Numerical results and discussion reveal that the proposed scheme is effective in making a good network selection in situations where there is a conflict among different QoS requirements for different WBAN applications.     

An Improved Pillar K-Means Based Protocol for Privacy-Preserving Location Monitoring in Wireless Sensor Network

A number of tiny sensor nodes are strategically placed in and around the human body to obtain physiological information. The sensor nodes are connected to a coordinator or a data collector to form a wireless body area network (WBAN). WBAN consists of variety of medical and non-medical applications with aggregate data rate requirement ranging from few bytes per second to 10 Mbps. These applications are having relatively different energy saving, reliability and quality of service (QoS) requirements. For example, emergency medical data are highly erratic but should be transferred with high reliability and minimum delay, whereas electrocardiogram and electroencephalogram applications are constant bit rate traffic which need to be transferred with moderate reliability. Additionally, non-medical applications include variable bit rate traffic and their jitter and delay requirements must also be met. On the above, a sensor node should spend minimum energy and conserve power to increase its life time in the network. The existing media access control (MAC) protocols present in various short and medium range wireless technologies such as 802.11 and 802.15.4 have been designed for specific purposes, and therefore, do not fulfill the diverse performance requirements across all WBAN applications. In this paper, we propose a poll-based MAC protocol, PMAC for WBAN, which can meet such diversified functional requirements of various WBAN applications. In particular, we introduce few concepts in polling based channel access mechanism to make an energy efficient and QoS aware MAC protocol. The design has been validated by obtaining the performance of proposed PMAC protocol through simulation.     

A cross-layer scheduling algorithm with QoS support in wireless networks

Scheduling plays an important role in providing quality of service (QoS) support to multimedia communications in various kinds of wireless networks, including cellular networks, mobile ad hoc networks, and wireless sensor networks. The authors propose a scheduling algorithm at the medium access control (MAC) layer for multiple connections with diverse QoS requirements, where each connection employs adaptive modulation and coding (AMC) scheme at the physical (PHY) layer over wireless fading channels. Each connection is assigned a priority, which is updated dynamically based on its channel and service status; the connection with the highest priority is scheduled each time. The authors' scheduler provides diverse QoS guarantees, uses the wireless bandwidth efficiently, and enjoys flexibility, scalability, and low implementation complexity. Its performance is evaluated via simulations.     

Soft QoS provisioning using the token bank fair queuing scheduling algorithm

Future-generation wireless packet networks will support multimedia applications with diverse QoS requirements. Much of the research on scheduling algorithms has been focused on hard QoS provisioning of integrated services. Although these algorithms give hard delay bounds, their stringent requirements sacrifice the potential statistical multiplexing performance and flexibility of the packet-switched network. Furthermore, the complexities of the algorithms often make them impractical for wireless networks. There is a need to develop a packet scheduling scheme for wireless packet-switched networks that provides soft QoS guarantees for heterogeneous traffic, and is also simple to implement and manage. This article proposes token bank fair queuing (TBFQ), a soft scheduling algorithm that possesses these qualities. This algorithm is work-conserving and has a complexity of O(1). We focus on packet scheduling on a reservation-based TDMA/TDD wireless channel to service integrated real-time traffic. The TBFQ scheduling mechanism integrates the policing and servicing functions, and keeps track of the usage of each connection. We address the impact of TBFQ on mean packet delay, violation probability, and bandwidth utilization. We also demonstrate that due to its soft provisioning capabilities, the TBFQ performs rather well even when traffic conditions deviate from the established contracts.     

Power Efficient Video Multipath Transmission over Wireless Multimedia Sensor Networks

This paper proposes a power efficient multipath video packet scheduling scheme for minimum video distortion transmission (optimised Video QoS) over wireless multimedia sensor networks. The transmission of video packets over multiple paths in a wireless sensor network improves the aggregate data rate of the network and minimizes the traffic load handled by each node. However, due to the lossy behavior of the wireless channel the aggregate transmission rate cannot always support the requested video source data rate. In such cases a packet scheduling algorithm is applied that can selectively drop combinations of video packets prior to transmission to adapt the source requirements to the channel capacity. The scheduling algorithm selects the less important video packets to drop using a recursive distortion prediction model. This model predicts accurately the resulting video distortion in case of isolated errors, burst of errors and errors separated by a lag. Two scheduling algorithms are proposed in this paper. The Baseline scheme is a simplified scheduler that can only decide upon which packet can be dropped prior to transmission based on the packet’s impact on the video distortion. This algorithm is compared against the Power aware packet scheduling that is an extension of the Baseline capable of estimating the power that will be consumed by each node in every available path depending on its traffic load, during the transmission. The proposed Power aware packet scheduling is able to identify the available paths connecting the video source to the receiver and schedule the packet transmission among the selected paths according to the perceived video QoS (Peak Signal to Noise Ratio—PSNR) and the energy efficiency of the participating wireless video sensor nodes, by dropping packets if necessary based on the distortion prediction model. The simulation results indicate that the proposed Power aware video packet scheduling can achieve energy efficiency in the wireless multimedia sensor network by minimizing the power dissipation across all nodes, while the perceived video quality is kept to very high levels even at extreme network conditions (many sensor nodes dropped due to power consumption and high background noise in the channel).     

Traffic scheduling in a photonic packet switching system with QoSguarantee

The main challenge in the design of future broadband networks is to efficiently support high-bandwidth multimedia services. Recent advances in the optical networking reveal that all optical networks offering multigigabit rate per wavelength may soon become economical as the underlying backbone in wide area networks, in which photonic switch plays a central role. Two issues are the essential in the design of photonic packet switching, the support of end-to-end virtual connections and the support of diverse quality-of-service (QoS) services. Existing work in wide-area optical networks has largely focused on the former, relatively less attention has been given to support heterogeneous traffic types and to satisfy the potentially different QoS requirements of different types of traffic. In this paper, we introduce a novel hierarchical scheduling framework to use in a class of photonic packet switching systems based on WDM, in which we separate the flow scheduling from the transmission scheduling. We show such separation is essential for achieving scalability such that large input-output ports can be accommodated, and also for offering flexibility in that optimal scheduling algorithms can be derived in different level that can be best tuned to the specific system requirements. The salient feature of the proposed scheduling mechanism is that it takes into account potentially different QoS requirements from different traffic flows. A number of interesting findings are observed from the results obtained by both analysis and simulation: (1) QoS requirements can be satisfied for both real-time and nonreal-time flows; (2) the impact Of the real-time traffic head-of-line (HoL) blocking on the system throughput can be effectively alleviated with the prevailing number of traffic flows. In addition, we investigate a variety of performance measures under different system configurations     

Cross-Layer MAC Protocol and Holistic Opportunistic Scheduling with Adaptive Power Control for QoS in WiMAX

Providing quality of service (QoS) to different service classes with integrated real-time and non-real-time traffic is an important issue in broadband wireless access networks. Opportunistic MAC (OMAC) is a novel view of communication over spatiotemporally varying wireless link whereby the multi-user diversity is exploited rather than combated to maximize bandwidth efficiency or system throughput. It combines cross-layer design features and opportunistic scheduling scheme to achieve high utilization while providing QoS support to various applications. Channel characteristics, traffic characteristics and queue characteristics are the essential factors in the design of opportunistic scheduling algorithms. In this paper, we propose a cross-layer MAC scheduling framework in WiMAX point-to-multipoint (PMP) systems and a corresponding opportunistic scheduling algorithm with an adaptive power control scheme to provide QoS support to the heterogeneous traffic. Extensive simulation experiments have been carried out to evaluate the performance of our proposal. The simulation results show that our proposed solution can improve the performance of the WiMAX PMP systems in terms of packet loss rate, packet delay and system throughput.     

Fairness-aware radio resource management for medical interoperability between WBAN and WLAN

Wireless body area networks (WBANs) in the industrial, scientific, and medical (ISM) bands have been increasingly adopted for various medical applications. Due to the shared nature of the ISM bands, when a WBAN coexists with a wireless local area network (WLAN), performance of WBAN may significantly degrade because of asymmetric attributes between WBAN and WLAN such as transmit power and response time. In this paper, we propose a novel channel access protocol for achieving effective channel sharing in the aspect of efficiency and fairness, which adaptively controls the contention window size of WLAN based on the delay information of WBAN. Our extensive simulation results for real-time electrocardiogram (ECG) monitoring show that the proposed scheme can guarantee the required quality of service of WBAN while insignificant degradation of WLAN performance.     

TF‐CPABE: An efficient and secure data communication with policy updating in wireless body area networks

The major challenge in wireless body area networks (WBAN) is setting up a protected communication between data consumers and a body area network controller while meeting the security and privacy requirements. This paper proposes efficient and secure data communication in WBANs using a Twofish symmetric algorithm and ciphertext‐policy attribute‐based encryption with constant size ciphertext; in addition, the proposed scheme incorporates policy updating to update access policies. To the best of the author's knowledge, policy updating in WBAN has not been studied in earlier works. The proposed scheme is evaluated in terms of message size, energy consumption, and computation cost, and the results are compared with those of existing schemes. The result shows that the proposed method can achieve higher efficiency than conventional methods.     

Optimal rate allocation and QoS-sensitive admission control in wireless integrated networks

The problem of Call Admission Control and rate allocation in loosely coupled wireless integrated networks is investigated. The related Radio Resource Management schemes were introduced to improve network performance in wireless integrated networks. However, these schemes did not reflect the independence and competitiveness of loosely coupled wireless integrated networks. Furthermore, given that users have different requirements for price and Quality of Service (QoS), they are able to select a network according to their preference. We consider a scenario with two competitive wireless networks, namely Universal Mobile Telecommunications System cellular networks and Wireless Local Area Networks. Users generate two types of traffic with different QoS requirements: real-time and non-real-time. We propose a scheme that exploits a mathematical model for the control of call admission and adopt a noncooperative game theory-based approach to address the rate allocation problem. The purpose is to maximize the revenue of the network providers while guaranteeing a level of QoS according to user needs. Simulation results show that the proposed scheme provides better network performance with respect to packet loss rate, packet delay time, and call-blocking probability than other schemes when the data rates are allocated to each call at the point that maximizes the revenue of network providers. We further demonstrate that a Nash equilibrium always exists for the considered games.     

Fair Class-Based Downlink Scheduling with Revenue Considerations in Next Generation Broadband Wireless Access Systems

The success of emerging Broadband Wireless Access Systems (BWASs) will depend, among other factors, on their ability to manage their shared wireless resources in the most efficient way. This is a complex task due to the heterogeneous nature, and hence, diverse Quality of Service (QoS) requirements of different applications that these systems support. Therefore, QoS provisioning is crucial for the success of such wireless access systems. In this paper, we propose a novel downlink packet scheduling scheme for QoS provisioning in BWASs. The proposed scheme employs practical economic models through the use of novel utility and opportunity cost functions to simultaneously satisfy the diverse QoS requirements of mobile users and maximize the revenues of network operators. Unlike existing schemes, the proposed scheme is general and can support multiple QoS classes with users having different QoS and traffic demands. To demonstrate its generality, we show how the utility function can be used to support three different types of traffic, namely best-effort traffic, traffic with minimum data rate requirements, and traffic with maximum packet delay requirements. Extensive performance analysis is carried out to show the effectiveness and strengths of the proposed packet scheduling scheme.     

Provisioning of Parameterized Quality of Service in 802.11e Based Wireless Mesh Networks

There has been a growing interest in the use of wireless mesh networks. Today’s wireless technology enables very high data rate up to hundreds of Megabits per second, which creates the high demand of supporting real-time multimedia applications over wireless mesh networks. Hence it is imperative to support quality of service (QoS) in wireless mesh networks. In this paper, we design a framework to provide parameterized QoS in 802.11e based wireless mesh networks. Our framework consists of admission control algorithms and scheduling algorithms, which aim at supporting constant bit-rate (CBR) traffic flows, as well as variable bit-rate (VBR) traffic flows. We first present deterministic end-to-end delay bounds for CBR traffic. We then prove that the delay of VBR traffic can be bounded if the traffic flow conforms to a leaky-bucket regulator. We further study different admission control algorithms for VBR traffic. Our simulation results show that, by taking advantage of statistical multiplexing, much more traffic flows can be admitted.     

Analysis of M-LWDF fairness and an enhanced M-LWDF packet scheduling mechanism

Modified largest weighted delay first(M-LWDF)is a typical packet scheduling algorithm for supporting hybrid real-time services over wireless networks.However,so far,there is little literature available regarding the theoretic analysis of M-LWDF fairness.This paper gives a theoretic analysis of M-LWDF fairness,which shows that M-LWDF fairness is related to channel condition,packet’s arrival process and the ratio of quality of service(QoS)requirements of different service queues.Given service QoS requirements and other parameters related to channel model and packet’s arrival process,the fairness is merely related to the ratio of the number of users in the service queues.Based on the analysis,an enhanced M-LWDF algorithm(EM-LWDF)is proposed and demonstrated in this paper.EM-LWDF is strictly designed in light of the fairness criteria of QoS requirements,so its fairness is almost not related to the ratio of the number of users in the service queues,and the theoretical value of fairness index is equal to 1.Simulation results validate the theoretic analysis and show the effectiveness of EM-LWDF in improving fairness.     

Utility Based Short-term Throughput Driven Scheduling Approach for Efficient Resource Allocation in CDMA Wireless Networks

In this paper, we address the problem of efficient recourse allocation in CDMA wireless networks supporting multimedia services with various and often diverse QoS prerequisites, placing special emphasis on real-time services’ essential requirements satisfaction. We first provide an analytical framework for studying real-time users’ short-term delay and throughput properties under fundamental opportunistic scheduling policies. The corresponding results demonstrate that probabilistic delay constraints are insufficient indicators of real-time services’ QoS prerequisites, while probabilistic short-term throughput requirements are more appropriate in asserting their performance expectations. Based on these observations and results, we propose and develop a scheduling policy for efficiently supporting heterogeneous services that include delay-tolerant non-real-time and delay-sensitive real-time services, over a wireless CDMA system under a common utility based framework. A user’s utility characterizes his degree of satisfaction for the received service as well as QoS expectations fulfillment, in a normalized way. Aiming at the maximization of users’ utilities, both non-real-time services’ long-term and real-time services’ short-term throughput QoS requirements are met, under the proposed opportunistic scheduler. Finally, via modeling and simulation it is demonstrated that significant performance improvements concerning both types of services’ QoS requirements satisfaction are achieved through the proposed scheduling approach.     

The integration of ad hoc sensor and cellular networks for multi-class data transmission

This paper targets mobile telemedicine applications that can be supported using third generation (3G) cellular networks, to provide highly flexible medical services. On the other hand, large-scale Ad hoc Sensor Networks (ASN), when deployed among mobile patients who may carry different kinds of micro-sensors to measure ECG, blood pressure, basal temperature or other physiological data, can provide a dynamic data query architecture to allow the medical specialists to monitor patients at any place. So far very little research has been conducted to explore the possibility of integrating ASN with mobile telemedicine. In this paper: 1. we suggest an integrated architecture that takes advantage of the low cost mobile sensor networks and 3G cellular networks to support multimedia medical calls with differentiated Quality-of-Service (QoS) requirements. 2. We propose a low-energy, distributed, concentric-zone-based data query mechanism that has the advantages of both proactive and reactive ad hoc routing algorithms to collect medical results from large-scale mobile patients for medical specialists who use cellular network to report patient data to the medical center. 3. In order to minimize the ambulance wireless call-dropping rate, we adopt accurate resource reservation call admission control (CAC) scheme to allocate the necessary bandwidth in the destination cell. 4. In order to meet the QoS requirements of patients’ wireless calls, we use dynamic guard channel CAC scheme to keep their handoff-call dropping rate below a certain threshold. We evaluate the validity of our schemes through simulations and analyze their performance. Our results clearly indicate the efficiency of the proposed CAC and sensor network query algorithms to meet the multimedia telemedicine QoS requirements.     

MiFi: a framework for fairness and QoS assurance for current IEEE 802.11 networks with multiple access points

In this paper, we present a framework for providing fair service and supporting quality of service (QoS) requirements in IEEE 802.11 networks with multiple access points (APs). These issues becomes critical as IEEE 802.11 wireless LAN are widely deployed in nationwide networks, linking tens of thousands of "hot-spots" for providing both real-time (voice) and non real-time (data) services to a large population of mobile users. However, both fairness and QoS guarantees cannot be supported in the current 802.11 standard. Our system, termed MiFi, relies on centralized coordination of the APs. During any given time of the "contention-free" period only a set of non-interfering APs is activated while the others are silenced. Moreover, the amount of service granted to an AP is proportional to its load and the system's performance is optimized by employing efficient scheduling algorithms. We show that such a system can be implemented without requiring any modification of the underlying MAC protocol standard or the behavior of the mobile stations. Our scheme is complementary to the emerging 802.11e standard for QoS and guarantees to overcome the hidden node and the overlapping cell problems. Our simulations establish that the system supports fairness and hence can provide QoS guarantees for real-time traffic, while maintaining a relative high throughput.     

A novel real-time scheme for (m,k)-firm streams in wireless sensor networks

The multimedia transmission based real-time applications have posed a big challenge to wireless sensor networks (WSNs) where both reliability and timeliness need to be guaranteed at the same time, to support an acceptable Quality of Service (QoS). The existing real-time routing protocols, however, are not able to meet the QoS requirements of realtime applications because of the inherent resource constraint of sensor nodes and instability of wireless communication. Therefore, we propose a real-time scheme in this paper, including a QoS-aware routing protocol and a set of fault recovery mechanisms, for (m,k)-firm based real-time applications over WSNs. A local status indicator which is specially devised for (m,k)-firm stream, is used for intermediate nodes to monitor and evaluate their local conditions. The proposed routing protocol takes into account of packet deadline, node condition and remaining energy of next hop, to make optimal forwarding decision. Additionally, according to the stream QoS and node condition, the proposed fault recovery mechanisms are utilized for nodes to handle the congestion, link failure and void problems occurred during transmission and remain the desired reliability and timeliness requirements. The proposed scheme has been well studied and verified through simulations. The results have proved the efficiency of the proposed scheme in terms of high successful transmission ratio, small end-to-end delay and long lifetime of network.     

Improving Quality of Service and Assuring Fairness in WLAN Access Networks

As public deployment of wireless local area networks (WLANs) has increased and various applications with different service requirements have emerged, fairness and quality of service (QoS) are two imperative issues in allocating wireless channels. This study proposes a fair QoS agent (FQA) to simultaneously provide per-class QoS enhancement and per-station fair channel sharing in WLAN access networks. FQA implements two additional components above the 802.11 MAC: a dual service differentiator and a service level manager. The former is intended to improve QoS for different service classes by differentiating service with appropriate scheduling and queue management algorithms, while the latter is to assure fair channel sharing by estimating the fair share for each station and dynamically adjusting the service levels of packets. FQA assures (weighted) fairness among stations in terms of channel access time without decreasing channel utilization. Furthermore, it can provide quantitative service assurance in terms of queuing delay and packet loss rate. FQA neither resorts to any complex fair scheduling algorithm nor requires maintaining per-station queues. Since the FQA algorithm is an add-on scheme above the 802.11 MAC, it does not require any modification of the standard MAC protocol. Extensive ns-2 simulations confirm the effectiveness of the FQA algorithm with respect to the per class QoS enhancement and per-station fair channel sharing     

Adaptive Online Sensor Clustering and Routing Algorithms for QoS Provisioning and Energy Efficiency

Due to the limited energy supply, energy efficiency is the most important issue for wireless sensor networks. In addition, next generation networks are also expected to support QoS sensitive data services. In this paper, a new online sensor network management scheme is developed for energy efficiency and QoS provisioning. To satisfy these conflicting requirements, the proposed scheme consists of clustering and routing algorithms. Without global network information, the online control paradigm is realized in a distributed way. Therefore, the principle contributions of these algorithms are its scalability and responsiveness to current network situations. Simulation results indicate the superior performance of the proposed schemes, while other schemes cannot offer such an attractive performance balance.     

A QoS Aware Dynamic Scheduling Scheme Using Fuzzy Inference System for IEEE 802.16 Networks

Providing quality of service (QoS) for diverse multimedia services is an important issue in IEEE 802.16 (WiMAX) networks. A scheduling mechanism that satisfies the QoS requirements has become more important for multimedia networks. In addition, scheduling algorithms for wireless networks are much more complex than that of wired networks because of channel quality variations and radio resource limits. This paper introduces a QoS Aware Scheduling System, based on fuzzy logic, for traffic management in WiMAX point-to-multi-point (PMP) networks. The proposed method attempts to guarantee delay and throughput QoS criteria. It considers QoS criteria and radio quality of each user in decision making processes. A series of simulation experiments have been carried out to evaluate the performance of the proposed scheduling system. The results show that the proposed method performs effectively to achieve QoS criteria and attains significant system performance for different types of traffic.