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Advances in microelectronics and integrated circuits, system-on-chip design, wireless communication and intelligent low-power sensors have empowered the development of Wireless Body Area Network (WBAN). IEEE 802.15.6 standard, approved in 2012, targets at wireless body area network. The network simulator 2 (NS-2) is a popular and powerful simulation tool, which provides substantial support for simulation...
This paper presents a novel medium access control (MAC) mechanism for wireless local area network (WLAN) systems, called visual recognition based medium access control (VRMAC) mechanism. VRMAC exploits Wi-Fi and visible light communications techniques, using LEDs and a camera to facilitate collision-less medium access with low overhead. In VRMAC, stations (STAs) equipped with LEDs send medium-access...
In recent years smart antennas are acknowledged as a prominent PHY layer technology, which can be used for spatial multiplexing, transmit/receive diversity, adaptive beamforming and interference cancellation. In this paper spatial multiplexing and reuse (due to interference cancellation) features of smart antennas are considered to improve the throughput of wireless mesh networks with MIMO. We present...
For satisfying requirements of the medical application, the IEEE 802.15 Task Group approved the IEEE 802.15.6 communication standard which is optimized for the low power device. In this paper, we analyze the performance of the IEEE 802.15.6 MAC protocol, in terms of throughput, delay-time and energy consumption under the saturation and unsaturation conditions. Considering the idle state of nodes,...
A decentralized adaptive range expansion for small cells deployed in the macro cell coverage area is proposed and analyzed in WCDMA heterogeneous networks. The algorithm is based on a direct traffic balancing between macro and small cells assuming that the macro cell periodically informs all other cells in its coverage area on its load using some adaptation performance metric. Then, each small cell...
In this paper, we deal with a dynamic and stochastic admission control and mobile association problem in an heterogeneous wireless network. We extend the usual problem by adding mobility features described by a Markov Modulated Poisson Process. The aim is to optimize the average performance of the system. This dynamic control problem is modeled and solved using a Semi Markov Decision Process (SMDP)...
Recently, video transmission over HSDPA has attracted more and more attentions. The traditional scheduler in HSDPA is designed to meet the QoS requirements such as delay, throughput, fairness and so on. In order to deeply study the performance of video transmission over HSDPA, we make a comprehensive research for the eight state-of-the-art scheduling schemes in HSDPA, such as RR, MAX C/I, PF, EDF,...
Today in various fields, Low-Rate Wireless Personal Area Network (LR-WPAN) with IEEE 802.15.4 can be utilized for various applications such as Home Automation, Factory Automation, Search & Rescue, Environmental Control, Health Monitoring, etc. In some of the applications, there is no issue of energy consumption; however, there are so many in which energy consumption is a major issue. In fact,...
Wireless networking enhanced with multiple transmitting channels has been considered to improve the utilization of the electromagnetic spectrum and to provide ways to accommodation the growing demand for connectivity. In this scenario, the use of a common control channel to coordinate the stations and networking resources is usually employed. This work evaluates the control channel capacity and its...
This paper proposes an approximate method, equivalent access intensity (EAI), for the throughput analysis of CSMA wireless networks in which links have finite offered-load and their MAC-layer transmit buffers may be empty from time to time. Different from prior works that mainly considered the saturated network, we take into account in our analysis the impacts of empty transmit buffers on the interactions...
Hidden node collision is a significant problem in CSMA/CA (Carrier-Sense Multiple Access with Collision Avoidance)-based multihop networks such as wireless sensor networks. The RTS/CTS (Request to Send/Clear to Send)-based handshaking mechanism is not effective to solve this problem in multihop networks. Also, to reduce power-consumption, such a handshaking mechanism is not used in CSMA/CA networks...
This paper advocates for a new Medium Access Control (MAC) strategy for wireless meshed networks by identifying overload scenarios in order to provide additional channel access priority to the relay. The key behind our MAC protocol is that the relay will adjust its back off window size according to the incoming and outgoing packet ratio. We describe the new protocol as an extension to the CSMA/CA...
Inter-user interference degrades the reliability of data delivery in Wireless Body Sensor Networks (WBSNs) in dense deployments when multiple users wearing WBSNs are in close proximity to one another. The impact of such interference in realistic WBSN systems is significant but has not been well explored. To this end, we investigate and analyze the impact of inter-user interference in practical WBSN...
This paper proposes a new wireless MAC protocol called Optimal DCF (O-DCF). O-DCF modifies the rule of adapting CSMA parameters, such as backoff time and transmission length, based on a function of the supply-demand differential captured by the local queue length. O-DCF is fully compatible with 802.11 hardware, so that it can be easily implemented only with a simple device driver update. O-DCF is...
IEEE 802.15.4 defines a popular MAC standard for wireless sensor and actuator networks. With the default parameters, under medium to high load, 802.15.4 generates excessive collisions and packet losses. Low duty cycles even exacerbate the problem, because more nodes become active after long periods of sleep and contend for channel access. In this paper, we have applied the models that led to the Idle...
Wireless local area networks (WLANs) adopted IEEE 802.11 based carrier sense multiple access with collision avoidance (CSMA/CA) multiple access control (MAC) protocol. Throughput in a WLAN significantly depends on the minimum contention window (CW) parameter of CSMA/CA MAC protocol. Without considering the capture effect, i.e., by using a protocol model, G. Bianchi models the optimal value of the...
As larger numbers of Wireless Sensor Network (WSN) applications get deployed in our homes and offices, it is desirable to use the same network to run different applications. We present and analyze the problem of scheduling and supporting the execution of multiple heterogeneous applications on top of the same WSN. First, we establish that using the same MAC or network protocol is not sufficient to...
Considering the particularity of underwater acoustic channel and the performance of underwater acoustic sensor networks, this paper presents a MAC layer protocol based on CDMA with throughput adaptive regulation and energy-efficient (TAEE-CDMA) protocol. On the premise that the MAI problem was suppressed, the protocol firstly used Lagrange multiplier method to make the node run with minimum energy...
Backoff algorithm is a technique to reduce packet collisions and to improve throughput efficiency in wireless local area network (WLAN). In this research, we propose a new backoff algorithm which is named Binary Exponential Increment Half Decrement (BEIHD) backoff algorithm. Furthermore, we introduce a new discrete Markov chain model for modeling the performance analysis of wireless local area network...
The aim of this paper is to examine the benefit of rapid dynamic antenna tilting on a WCDMA cellular network, where dynamic antenna tilting is applied as either a SON implementation or a MIMO implementation. The potential network performance improvement of this technique is evaluated using a dynamic WCDMA/LTE simulator and the results presented suggest that downlink performance gains of up to 89%...
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