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Traditional time division multiple access (TDMA)-based medium access control (MAC) protocols for wireless sensor networks (WSNs), for example, low-energy adaptive clustering hierarchy (LEACH), allocate one time slot for each node within a cluster. For nodes that have no data to send, the radio module is still active. Such approaches drain the precious battery energy. In this study, the authors propose a novel TDMA-based MAC protocol to conserve energy and increase data transmission efficiency of sensors in a cluster-based WSN. In the proposed scheme, nodes that have no data to send can go into sleep mode for energy conserving. On the other hands, nodes that have more data to send can ask the cluster head to allocate more time slots for data transmission. Experiments show that the proposed MAC protocol can have better performance than traditional TDMA-based MAC protocols. [ABSTRACT FROM AUTHOR]

In this study, the authors consider the benefits of mobile terminals (MTs) with different access points (APs) for uplink and downlink transmission to conserve MTs' energy. In traditional cellular networks, an MT is typically associated with a single AP. However, as wireless networks evolve, heterogeneous and/or overlay deployment scenario become viable and an MT can be associated with different APs for uplink and downlink transmission. The authors call this 'dual APs association'. The authors show that allowing dual APs association provides a significant gain on the uplink system capacity and/or the uplink transmit power savings. As a specific example of the use of dual APs, the authors focus on relay networks and show that considering the relay cost further increases the benefits of this approach. Based on extensive simulations using IEEE 802.16m relay network Evaluation Methodology, the authors demonstrate that dual APs can improve the uplink harmonic capacity by 350% or reduce the uplink transmit power by 7 dB. The authors note, however, that there exists a signalling cost in implementing dual APs association, which needs be overcome to achieve these substantial performance improvements. [ABSTRACT FROM AUTHOR]

In wireless sensor networks (WSNs), sink mobility has been drawing more and more attention in recent years. Some approaches suggest that mobile sinks repeatedly propagate packets to notify the potential sources of their latest location information. As a result, frequent location updates from multiple sinks introduce both increased transmission traffic and rapid power expenditure. In order to reduce power consumption and minimise the overhead of frequently propagating packets, the authors propose a power-aware data dissemination (PADD) protocol for grid-based WSNs with mobile sinks. Rather than propagate the query messages from each sink to all sensor nodes to establish data forwarding information, a source constructs a grid structure beforehand so that only the dissemination nodes located at grid points need to acquire forwarding information. A properly grid cell size is determined to ensure that a dissemination node can directly communicate each other with its eight neighbouring dissemination nodes. As a result, a message can traverse not only vertically or horizontally but diagonally as well. Besides, dissemination nodes with the most residual energy are selected for forwarding query and disseminating data to evenly distribute energy load in the sensor field. Simulation results demonstrate the effectiveness of PADD in reducing the energy consumption and prolonging the network lifetime. [ABSTRACT FROM AUTHOR]

This article studies the power allocation (PA) problem for dual-hop orthogonal-frequency-division-multiplexing (OFDM) relaying networks, in which a source communicates with a destination with the help of multiple amplify-and-forward relays that employ parallel transmission protocol. The objective is to maximise the system achievable rate, under which an aggregate power constraint is imposed on all relays, and an individual link rate constraint is imposed on each OFDM subchannel. Based on Zhao et al's prior work, the simpler PA problem without considering those rate constraints is firstly solved by optimally allocating the total power across all OFDM subchannels. Then, for the original problem with both power and rate constraints, an order structure is proposed such that in the optimal PA scheme, those subchannels that attain respective maximum link rates are determined one by one, that is the complexity to determine those subchannels is considerably reduced from exponential to linear order. [ABSTRACT FROM AUTHOR]

Contention-based geographic forwarding (CGF) is a state-free communication paradigm for data delivery in multihop wireless sensor networks. CGF is robust to frequent topology changes, scalable to large-scale node deployment and applicable to data-centric applications and resource constrained networks. However, CGF may experience significant performance degradation under unreliable links. In this work, we present the intelligent CGF (ICGF) to combat the channel variation. IGCF combines the advantages of both cooperative and contention-based forwarding, involving multiple neighbours of the sender into the local forwarding to improve the transmission reliability. ICGF differs from existing work in that it extends the cooperation scope intelligently, by sending one additional control message on demand. For this reason, the probability of cooperation void in ICGF is decreased and the single-hop packet progress is increased. The authors conduct extensive simulations to study the performance of the proposed ICGF compared with existing protocols. Simulation results demonstrate that ICGF improves the end-to-end data delivery delay, energy efficiency and data delivery ratio. [ABSTRACT FROM AUTHOR]

This study addresses the problem of resource allocation for a multi-class time-slotted optical overlapped code-division multiple access network. A delay-constraint fair resource allocation (DC-FRA) scheme is considered with the quality of service requirements on both physical layer signal-to-interference ratio and network layer average packet delay. A cross-layer approach in allocating the transmission power and rate for every class of users in the network is considered. The performances of the S-ALOHA, R-ALOHA and R3T medium access control protocols have been investigated in the DC-FRA scheme. It is shown that the R-ALOHA protocol has the highest throughput and the minimum average packet delay. On the other hand, although the DC-FRA allocates the largest bandwidth under the R-ALOHA protocol, it forces the users to transmit with relatively higher power in comparison with the power required for the S-ALOHA and the R3T protocols. In addition, the packets exhibit much smaller delay when using the DC-FRA, especially at low and moderate throughput for the three protocols. [ABSTRACT FROM AUTHOR]

Digital communication networks are a core technology in advanced building automation systems. Building automation and control network (BACnet), a data communication protocol designed specifically for building automation and control systems, uses the master-slave/token-passing (MS/TP) protocol as one of its field-level networks. Previously, the authors introduced a basic concept of bandwidth allocation for MS/TP to improve its real-time communication capability. In this study, the authors developed a communication module that implements the proposed scheme, and used it in an experimental model to examine the validity of the bandwidth allocation scheme for MS/TP. Experimental results show that the modified MS/TP protocol satisfies the requirements for real-time communications using cyclic and life-safety messages in BACnet communication services. [ABSTRACT FROM AUTHOR]

Synchronous bandwidth, defined as the maximum time a node is allowed to send its synchronous messages while holding the token, is a sensitive parameter for deadline guarantees of synchronous messages in a timed token network. In order to offer such guarantees, synchronous bandwidth has to be allocated carefully. The allocation of synchronous bandwidths to a general synchronous message set with the minimum message deadline (Dmin) larger than the target token rotation time is studied. A new approach for allocating synchronous bandwidth, which can be easily implemented in practice, is proposed. It is demonstrated, through simulations and numerical examples, that the proposed approach performs better than any of previously proposed local synchronous bandwidth allocation schemes, in terms of its ability in guaranteeing hard real-time traffic. [ABSTRACT FROM AUTHOR]

The cognitive cooperative system with coexisting scenario of multiple primary users and one secondary capable of relaying is considered in this study. The primary users transmit packets in orthogonal subchannels. According to the cognitive principle, the secondary activity cannot interfere with the primary performance. Therefore in this study, the secondary user makes use of the spectrum when sensed idle. Based on the proposed media access control (MAC) protocol, the authors derive the stable throughput and delay slots expressions of each primary user with secondary relaying. They also achieve the stable network constraints of relaying probability ℇ, the feasible range of primary arrival rates and the maximum allowed secondary transmitting power which is to make a tradeoff between the stable throughput of the primary and secondary user. Simulation results show that secondary relaying can increase the primary and secondary throughput and also reduce the delay slots when designing an appropriate ℇ. [ABSTRACT FROM AUTHOR]

Vehicular sensor networks (VSN) has recently become a hot research topic in the field of wireless networking, as this promising technology has potentials to provide variety of applications and safety to drivers on the road. As promising it is, VSN also introduces many new challenges to the table. For example, the vehicle mobility creates a very unique topology with frequent network disconnections, which may pose problems when existing network protocols for general ad hoc networks are applied. Majority of the research related with VSN limit their data harvesting schemes to only single-hop or short distance transmissions. Therefore these works cannot meet real-time requirements nor support applications where data must be transmitted in multi-hop. The authors believe such problems can be alleviated by our proposed scheme, named ‘multi-hop data harvesting’ (MDH). The simulation studies conducted using QualNet 4.0 simulator shows the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

In a mobile ad hoc network (MANET) with multiple Internet gateways, efficient management of mobile IP functionality supporting seamless data services is a major challenge. The inadequacy of existing mobile IP schemes applicable to MANETs motivated the search for more efficient gateway discovery/handoff schemes. A solution for mobile IP-based gateway discovery/handoff in dynamic source routing (DSR)-based MANET is formulated. Enhanced mobile IP protocol suitable for MANET environment, i.e. the mobile IP registration controller, is designed. In particular, one of the most significant contributions deals with the mobile IP handoff triggering mechanism which is adaptively assisted by the DSR route maintenance mechanism. Simulation results are provided to support the idea. [ABSTRACT FROM AUTHOR]

Push-to-talk (PTT) is a walkie-talkie like service which performs an efficient and instant voice over Internet protocol (VoIP) communication in mobile ad hoc network especially for certain circumstances, such as battle field and earthquake or disaster relief. The authors have designed and implemented the PTT mechanism in ad hoc VoIP network. The PTT server and user agent combined with the pseudo session initiation protocol (SIP) server in the implementation provide the PTT service without standalone SIP server support. The authors also conduct the experimental measurements, in terms of delay and packet loss, in the test-bed to demonstrate the realisation of PTT service in ad hoc VoIP network. [ABSTRACT FROM AUTHOR]

In variable-speed electrical drives, data transmission between an electric motor and an inverter is required because of sensors installed at the motor. Sensor information is used both in the motor control and in the diagnostics. For example, a data transmission medium can be implemented either by additional cabling or through the power cable. However, additional cabling is neither a cost-effective nor even a reliable solution. Previously, only a few application-specific solutions for data transmission via power cables have been presented. A general method to implement a broadband and Ethernet-based communication medium between a motor and an inverter is proposed here. The method forms an Ethernet-supported packet-based communication medium over the motor power cable. Ethernet supports all kind of protocols implemented above the link layer. The channel and noise characteristics are described. According to these, a coupling interface is developed that allows installing the communication device safely to a three-phase inverter-fed motor power cable. A channel capacity analysis is also performed. Laboratory measurements are carried out and analysed with the proposed method, and two possible applications are discussed. [ABSTRACT FROM AUTHOR]

A directional routing approach for multihop ad-hoc networks, is presented which has been applied to two on-demand routing protocols: namely dynamic source routing (DSR) and ad-hoc on-demand distance vector routing (AODV). Both DSR-based and AODV-based directional routing protocols are designed to balance the trade-off between co-channel interferences from nodes hops away and the total power consumed by all the nodes. In order to select the best route, three metrics are considered in the route discovery process. They consist of hop count, power budget and overlaps between adjacent beams. By exploiting the direction of directional antennas, both routing protocols are capable of reducing overlaps between beams of the nodes along the route, thus eliminating interference. Arbitrary networks and random networks are considered in the simulations. The results show considerable performance gains for transmission of real-time traffic over ad hoc networks. [ABSTRACT FROM AUTHOR]

Dynamic source routing (DSR, introduced in 1996) is one of the most frequently used routing protocols for mobile ad-hoc networks (MANETs). Numerous MANET protocols were created based on DSR's algorithm. In addition to inheriting the overall performance specifications of DSR, these MANET protocols are designed to perform optimised for specific functionality. To name a few, these functionalities include: hierarchical routing, security-aware routing and multipath routing. Such flavoured DSR schemes (X-DSR) are often compared against the original DSR protocol through simulation results. The purpose of this survey is to first introduce DSR in detail, discuss most of the DSR flavours, point out their specific features, and to present a complete survey of the analyses given in the current literature against the original DSR protocol. Following this in-depth discussion, we introduce an X-DSR-aware management architecture, which utilises a multilayer scheme that imports parameters from different layers (network, data-link and physical) and performs current network condition matching compared to the closest pre-defined network condition groups. The output of such a match is the selection of the most optimal routing protocol, which satisfies most of the criteria of the pre-defined condition group. [ABSTRACT FROM AUTHOR]

The performance of multi-homed transport protocols tolerant of network failure is studied. It evaluates the performance of different retransmission policies combined with path failure detection thresholds, infinite or finite receive buffers for various path bandwidths, delays and loss rate conditions through stream control transmission protocol simulation. The results show that retransmission policies perform differently with different path failure detection threshold configurations. It identifies that retransmission of all data on an alternate path with the path failure detection threshold set to zero performs the best in symmetric path conditions but its performance degrades acutely in asymmetric path conditions even when the alternate path delay is shorter than the primary path delay. It illustrates that retransmission of all data on the same path with the path failure detection threshold set to one or zero gives the most stable performance in all path configurations. [ABSTRACT FROM AUTHOR]

In this article, the problem of providing a fair bandwidth allocation to the flows sharing a congested link in a router is investigated. Queue management, bandwidth share and congestion control are very important to both the robustness and fairness of the Internet. The buffer at the outgoing link is a simple FIFO, shared by packets belonging to the flows. A new transmission control protocol (TCP)-friendly router-based active queue management scheme, termed WARD, is proposed to approximate the fair queueing policy. WARD is a simple packet-dropping algorithm with a random mechanism which discriminates against flows that submit more packets per second than is allowed as their fair share. By doing this, it not only protects TCP connections from user datagram protocol flows, but also solves the problem of competing bandwidth among different TCP versions, such as TCP Vegas and TCP Reno. In addition, WARD works quite well for TCP flow isolation even with different round trip times. In other words, WARD improves the unfair bandwidth allocation properties. Furthermore, as it is stateless and easy to implement, WARD controls unresponsive or misbehaving flows with only a minimum overhead. [ABSTRACT FROM AUTHOR]

The non-collision packet reservation multiple access (NC-PRMA) protocol was proposed by Wen and Wang to eliminate the unstable phenomenon in the PRMA protocol under heavy load conditions by allocating dedicated control mini-slots to mobile terminals (MTs). However, this does not utilise the channel resource efficiently. A dynamic non-collision PRMA (DNC-PRMA) protocol has been proposed to dynamically allocate control mini-slots to MTs such that the channel resource can be utilised efficiently. Using simulation, the proposed DNC-PRMA protocol is shown to yield significantly higher channel utilisation, lower packet dropping probability and lower channel access delay than a protocol that allocates a dedicated mini-slot to each MT. [ABSTRACT FROM AUTHOR]

Multicast-based data communication is an efficient communication scheme especially in multihop ad hoc networks where the MAC layer is based on one-hop broadcast from one source to multiple receivers. The problem of resource allocation for a set of homogeneous multicast sessions over multihop wireless network is addressed. An iterative algorithm is proposed that achieves the optimal rates for a set of multicast sessions such that the aggregate utility for all sessions is maximised. The authors demonstrate analytically and through simulations that the algorithm achieves optimal resource utilisation while guaranteeing fairness among multicast sessions. The algorithm in network environments with asynchronous distributed computations has been further analysed. Two implementations for the algorithm based on different network settings are presented and show that the algorithm not only converges to the optimal rates in all network settings but it also tracks network changing conditions, including mobility and dynamic channel capacity. [ABSTRACT FROM AUTHOR]

In infrastructure wireless networks, the wireless hop can be considered as another hop of the transmission path. With the rapid growth of wireless traffics, the future wireless network is expected to provide services for heterogeneous data traffics with different quality of service (QoS) requirements. Most proposed schemes do not have adaptive mechanisms to deal with the environment changes. In real situation, bandwidths, error rates and loss rates of wireless links vary frequently. We will base on the differentiated service model and propose a wireless differentiation (WD) scheme for user datagram protocol (UDP) flows and a wireless differentiation with prioritised ACK scheme for connections with transmission control protocol (TCP) flows. Both schemes provide QoS support for IEEE 802.11b and do not change the basic access mechanism of IEEE 802.11b. [ABSTRACT FROM AUTHOR]

In order for third-generation partnership project (3GPP) networks to cope with the rapid growth of IP data traffic, the location management requires further enhancement to accommodate the burst data traffic characteristics of packet switched (PS) services. The universal mobile telecommunication system (UMTS) location management solutions for PS services in 3GPP networks has been investigated, and an inactivity counter mechanism in PS domain to reduce the location management cost of inactivate users has been proposed. An analytical model accommodating diverse call and mobility characteristics of user equipment to evaluate the performance of the inactivity counter mechanism has also been developed. Using the proposed model, the performance of the inactivity counter mechanism in UMTS terrestrial radio access network recommended by 3GPP is investigated, the cost reduction obtained by the proposed mechanism when compared with the original location strategy used in the PS domain is then analysed, which also shows the effect of system parameters and users' mobility and service patterns on the location management costs. [ABSTRACT FROM AUTHOR]

The results of a performance analysis of mobile agents in a distributed network environment are presented. Analytical models are developed and used to compare the performance of carrying out a simple management function with mobile agents (MA) or SNMP (simple network management protocol). An examination is made of how delay is affected by the size of the management domain and how each method behaves in both a local area network (LAN) and wide area network (WAN) environment. For large domains, optimal performance is obtained if the mobile agents' size is bounded, and this may require sharing the management task among a small number of mobile agents. [ABSTRACT FROM AUTHOR]

This paper explains how 3G high speed packet access (HSPA) works. High-speed packet access in both its flavours, HSPDA for the downlink and HSUPA for the uplink, is a hot topic in 3G. The real breakthrough has been achieved by dramatic improvements in the physical layer. This article explains what they are and how they lead to the kind of data rates needed to guarantee 3G a future in the evolution towards all-IP networks. [ABSTRACT FROM AUTHOR]

The recently emerging possibility of ubiquitous wireless connectivity has increased the importance of the effective radio bandwidth usage. In the case of distributed multiple access MAC algorithms are needed that lower the probability of collisions. The authors focus on a new wireless medium access procedure that aims to increase the efficiency of the radio bandwidth usage. The presented VTBM (virtual transmission based MAC) procedure is based on the dynamic p-persistent algorithm and uses a virtual transmission mechanism. Simulation results presented demonstrate that the proposed algorithm outperforms the exponential backoff algorithm used in 802.11 DCF MAC regarding throughput and collision rate. [ABSTRACT FROM AUTHOR]

The deployment of desktop videoconferencing, also known as video and voice over IP (VVoIP), over existing IP networks is gaining popularity. Such a deployment has become a major and challenging task for data network researchers and designers. An analytic approach for deploying videoconferencing is presented. The approach utilises queueing network analysis and investigates two key performance bounds for videoconferencing: delay and bandwidth. The approach can be used to assess the support and readiness of an existing IP network. Prior to the purchase and deployment of desktop videoconferencing equipment, the approach predicts the number of videoconferencing sessions or calls that can be sustained by an existing network while satisfying QoS requirements of all network services and leaving adequate capacity for future growth. As a case study, we apply our approach to a typical network of a small enterprise. In addition, we use OPNET network simulator to verify and validate our analysis. Results obtained from analysis and simulation are in line and give a close match. [ABSTRACT FROM AUTHOR]

Multicasting in mobile ad hoc networks (MANETs) poses several challenging problems. Though a number of multicast protocols for MANETs exist in the literature, there are many areas where improvements are desirable and possible. A new multicast protocol is proposed for MANET, called the gateway-based multicast protocol (GBMP) that seeks to improve upon the existing protocols in terms of the speed and the cost of the multicast tree repair mechanism, the transmission efficiency and the amount of control overhead. GBMP achieves these improvements by using a number of novel features, such as both global and local maintenance of group-shared trees, a bidirectional multicast tree repair mechanism and the suppression of unnecessary acknowledgments. In addition, we have introduced a new metric called weighted occurrence of consecutive packet loss to measure the discontinuity in data packet delivery. Extensive simulation study shows that GBMP outperforms the more established ODMRP and ADMR protocols in a number of important performance metrics under different traffic patterns and source node counts. [ABSTRACT FROM AUTHOR]

Tree-based reliable multicast protocols are well-known for being scalable for one-to-many sessions, but their behaviour in terms of throughput and bandwidth requirements has not been identifed for many-to-many sessions. In this paper, existing tree-based reliable multicast protocols are categorised into four classes according to their feedback/retransmission mechanisms. Analysing and comparing them using a new spatial multicast loss model that considers the correlation of packet loss events can yield realistic analysis results. The analysis reveals that for many-to-many sessions, tree-based protocols with unicast NACK, unicast retransmission, and periodic polling are most scalable with respect to throughput and network bandwidth for practical session sizes. The result is contrary to the one-to-many case and it is shown that the reason is that reducing the sender's processing time is a key factor for scaling one-to-many reliable multicast, whereas reducing the receiver's processing time is far more important factor for scalability of many-to-many reliable multicasts. [ABSTRACT FROM AUTHOR]

Focuses on the evolution of communication methods used in industrial application; Description of the benefits that CAN offers for industries; Advantages of using TCP/IP over Ethernet; Development of industrial-grade connectors and cabling for Ethernet.

A novel statistical model, the one-dimensional hyperbolic distribution, is proposed for network traffic activity. This includes the modelling of network traffic performance and descriptive parameters, organised as probability distribution functions of activity monitored during an observation window. This model promises accurate representation in a compact manner, of particular interest in statistical anomaly intrusion detection systems. The hyperbolic distribution has been tested in modelling several performance parameters in data traces of IP traffic collected from various actual network environments, including the campus LANs of the New Jersey institute of Technology and the WAN of the Bergen County Cooperative Library Network System (BCCLNS), as well as simulated client-server LANs. By fitting the model parameters to the experimental data, it is shown that this analytic model performs significantly better than the models currently in common use, such as the Weibull, Pareto, normal and lognormal distributions. [ABSTRACT FROM AUTHOR]

A system-on-a-chip is an interconnection of different pre-verified IP hardware blocks, which communicate using complex protocols. The integration of IP blocks requires some glue logic to interface otherwise incompatible datapaths. This glue logic is called a protocol converter and its manual design proves to be a tedious and time-consuming task. Automatic synthesis is therefore important, but for optimal system-level design it is necessary to consider not just the correctness, but also the quality (in terms of bandwidth and latency of data transfer) of the converter. A good solution to this problem will allow greater use of protocol-level abstraction as a design tool in system design and synthesis. Results are presented on automatic synthesis of a converter between two protocols. It is shown how converter logic which is bandwidth-optimal can be synthesised for datapaths with an arbitrary number of data ports each of which has arbitrary-size first-in first-out (FIFO) storage. An extension of the product FSM converter synthesis algorithm to include FIFO data-paths is presented. In addition the converter bandwidth is identified as a mean cycle graph problem which is solved using maximum mean cycle graph algorithms. [ABSTRACT FROM AUTHOR]

For the major signalling protocols SIP and H.323 in a multimedia communication session, the authors present a systematic method for designing gateways between call setup modes of the protocols using the supervisory control framework for nondeterministic discrete event systems. In particular, it is shown that the nonblockingness of a gateway to be designed is guaranteed by the nonblockingness of a language implementing a given specification described as specific messages. [ABSTRACT FROM AUTHOR]

Analyzes the suitability of architectures for delivering service over Internet Protocol networks with the expected service quality and reliability. Adaption layer used by the SIGTRAN architecture; Features of the Stream Control Transmission Protocol that improve reliability without compromising performance; Performance for error checking and correct delivery of messages.

In opportunistic networks, wireless nodes have to actively probe neighbours to establish intermittent links with minimal energy consumption and latency before transmission begins. The nature of opportunistic networking requires that nodes should discover each other even when: the probing intervals of neighbour nodes are asynchronous and the wake-up patterns are asymmetric. Proposed is a rendezvous protocol to facilitate neighbour discovery while satisfying the above requirement. It is demonstrated that it saves energy about 30% compared to existing schemes by a theoretical analysis. [ABSTRACT FROM AUTHOR]

A technique able to significantly reduce the energy consumption of contention-based MAC protocols for wireless sensor networks is presented. Address and timing information is embedded into the packet preamble, allowing receivers to power off their radio during part of the transmission. Analytical and experimental evaluations show a significant extension of the network lifetime. [ABSTRACT FROM AUTHOR]

Simulation of ETSI's High Performance Local Area Network Type 2 (HIPERLAN/2) is presented. MATLAB/Simulink modelling demonstrated that for 64-QAM mode, with coding rate 2/3, a data rate of 48 Mbit/s is achieved with 3.2 dB SNR improvement compared to coding rate 3/4 (with puncturing) as required for the maximum 54 Mbit/s. [ABSTRACT FROM AUTHOR]

Focuses on the role of circuit emulation services over packet (CESoP ) in the transition to an eventual all-IP network. Ways in which CESoP complements voice over-Internet-protocol; Need for the inter-working functions to perform the packetisation process with the lowest possible delay to have any possibility of faithfully replicating a time division multiplex service across an asynchronous packet switch network; Importance of clock recovery for the high performance delivered by CESoP.

Reports on the growth of wireless local area network connectivity in the U.S. Growth of wireless data market; Plan of McDonald's to launch its own Wi-Fi service.

The article focuses on some proposals for the use of real-time Ethernet in industries. Ethernet is starting to replace the industrial fieldbuses that were developed in the 1990s. There are now three proposals for real-time Ethernet. Two are from German companies: Siemens (PROFInet v3) and Beckhoff (EtherCAT ) and the third is from B&R Automation (Powerlink), based near Salzburg. All three rely on the basic Ethernet frame or "telegram" for communication. No high level protocol like TCP/IP is used, although Ethernet and TCP/IP may co-exist on the same cable.