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In this paper, we propose a new Medium Access Control (MAC) protocol for Wireless Sensor Networks (WSNs) called MMSMAC (Multi-Mode Sensor MAC protocol), which can operate and switch among three modes: synchronous, asynchronous, and hybrid, according to the application requirements. In the synchronous mode, MMSMAC organizes the sensor nodes under even and odd clusters. Each sensor node has its own...
In this paper, a distributed traffic-balancing routing protocol is proposed for multi-sink industrial wireless sensor networks that effectively distributes traffic from sources to sinks. Each node has a gradient field that is used to decide on a neighbor node to reach a sink. The node's gradient index contains (1) the distance cost from source to a respective sink, and (2) traffic information from...
Energy consumption in mobile networks, e.g. 3G networks, may be a substantial part of an operator's expenses. A large part of the total energy of the network is consumed by the radio access network. Today operators are saving energy by turning off carriers or cells during periods with low traffic by manually configuring on-off periods. At the same time, operators are seeking to increase cost efficiency...
High packet network have become an essential in modern multimedia communication. Shared buffer is commonly used to utilize the buffer in the switch. In this paper, we analyse the performance of shared buffer with different memory sizes. The architecture of the multi-class shared buffer is developed for 16×16 ports switch that is targeted in Xilinx FPGA. The performance of the multi-class shared buffer...
In this paper, we present an Multi-Dimensional Learning multiple access control scheme for cognitive radio users in unlicensed spectrum. The proposed scheme is developed by applying reinforcement learning to the perspectives of both channel assignment and retransmission policy based upon a multichannel p-persistent CSMA algorithm. In a distributed open spectrum sharing situation, decisions regarding...
The properties of underwater acoustic channel are quite different from those of terrestrial wireless sensor networks, which brings many challenges to design an efficient media access control (MAC) protocol for underwater acoustic sensor networks (UWASNs). In order to overcome the long propagation delay and the funneling effect of UWASNs, a MAC protocol, named path-oriented code assignment (POCA) CDMA...
A Module Matched First Dispatching (MMFD) algorithm for MSM Clos-network switches is proposed in this paper. Each output port of input modules and central modules has its own state pointer. At the beginning of each time slot, schedulers configure the state of each central module according to the value of each pointer. And then, cells switched in next time slot are selected on the basis of the configuration...
We describe here a new burst scheduling algorithm to avoid burst overlapping in the egress router of optical burst switching (OBS) network, and hence to improve the quality of service (QoS) in developing several optical networks to fulfill the increasing demand of Internet facilities. We consider TAG (tell-and-go) protocol where many lightpaths pass in a given link and burst overlap may occur. In...
Qos provision is considered as the complex task due to the heterogeneous nature, diverse QoS requirements of emergent different applications. With the advent of high bandwidth 3G/4G technologies, like LTE, LTE-advanced, the necessity of QoS provision becomes even crucial. Uplink scheduling with QoS provision is considered here. The contribution of this work is uplink packet scheduling scheme maintaining...
A framework for the joint design of wireless network and controllers is proposed. Multiple control systems are considered where the sensor measurements are transmitted to the controller over the IEEE 802.15.4 protocol. The essential issues of wireless networked control systems (NCSs) are investigated to provide an abstraction of the wireless network for a co-design approach. We first present an analytical...
In this paper, a semi-Markov model is established to characterize the throughput performance of CSMA networks. Based on the assumption of Poisson distributed aggregate traffic, the throughput expression of p-persistent CSMA is derived, which includes the results of 1-persistent CSMA and non-persistent CSMA presented in Kleinrock and Tobagis landmark paper as two special cases. The analysis further...
Fiber-Wireless (FiWi) access networks, have rapidly matured as a last mile Internet access network solution due to their novel combination of Ethernet Passive Optical Networks (EPON) as a backhaul and Wireless Mesh Networks (WMN) as an access network. The high bandwidth provided by the optical lines, as well as the flexibility offered by the wireless network, offers a great degree of cost-efficiency...
Distributed medium access control protocols can be classified into contention-based and contention-free protocols. In this paper, we analyse a contention-free distributed protocol where nodes make reservations on a first-come first-served basis. We evaluate the impact of this first-come first-served approach on the fairness regarding throughput and delay, by means of the ECMA-368. This standard establishes...
In this paper, we discuss the challenges associated with integrating multiuser OFDMA in a single cell IEEE 802.11 based wireless ad hoc network and propose a new, dynamic and robust approach to improve it. Our new MAC, using OFDMA in the physical layer, can incorporate multiple concurrent transmissions or receptions in a dynamic manner and can adjust the collision probability based on the traffic...
The MAC protocol is important, especially for wireless LAN because of limited bandwidth. A great deal of research has been carried out and some of proposed schemes are effective. Specifically, considerable effort has been devoted to improving the IEEE 802.11 standard which is utilized widely. Previous theoretical analysis gave the upper bound of IEEE 802.11 DCF throughput which is far below the channel...
Due to the significant growth of link speeds, amount of data that should be stored on router line cards are rapidly increasing. Therefore, a large number of memory modules are required for packet storage. In addition, a high performance interconnection network on line cards is strongly needed for inter-communication between processing elements and memory modules. In this paper we propose a new interconnection...
A multichannel scheduling based on an extension of modified largest weighted delay first (M-LWDF) scheduling is proposed for heterogeneous traffic. We consider the downlink of an orthogonal frequency division multiplexing (OFDM) system where the wireless channel and queue state information are taken into account to schedule delay-sensitive and ratesensitive traffic. We propose a logarithmic notion...
We analyze TCP-controlled bulk file transfers in a single station WLAN with nonzero propagation delay between the file server and the WLAN. Our approach is to model the flow of packets as a closed queueing network (BCMP network) with 3 service centres, one each for the Access Point and the STA, and the third for the propagation delay. The service rates of the first two are obtained by analyzing the...
We study the performance of cognitive (secondary) users in a cognitive radio network which uses a channel whenever the primary users are not using the channel. The usage of the channel by the primary users is modelled by an ON-OFF renewal process. The cognitive users may be transmitting data using TCP connections and voice traffic. The voice traffic is given priority over the data traffic. We theoretically...
IEEE 802.16 orthogonal frequency-division multiple access (OFDMA) downlink subframes have a special 2-D channel-time structure. Allocation resources from such a 2-D structure incur extra control overheads that hurt network performance. Existing solutions try to improve network performance by designing either the scheduler in the medium access control layer or the burst allocator in the physical layer,...
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