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IBM® PureFlex System: The Future of Datacenter Management by Ptak, Noel & Associates LLC
In this paper, Ptak/Noel describes the new IBM PureFlex system and the unique management capabilities of the IBM Flex System Manager.
3 days ago by IBMImproved Progressive Edge-Growth Algorithm for Fast Encodable LDPC Codes
The Progressive Edge-Growth (PEG) algorithm is known to construct Low-Density Parity-Check (LDPC) codes at finite code lengths with large girths by establishing edges between symbol and check nodes in an edge-by-edge manner. Low-Density Parity-Check (LDPC) codes, which were first proposed in the early 1960's and re-discovered in 1996, have recently attracted much attention due to their capacity-approaching performance and low decoding complexity. Since, their re-discovery, there are many methods such as the message-passing decoding and the linear program decoding that have been proposed for the decoding algorithm.
3 days ago by Springer Science+Business MediaA Taxonomy of Cross Layer Routing Metrics for Wireless Mesh Networks
Multi-hop, multi-channel, and multi-radio Wireless Mesh Networks (WMNs) are emerging as promising field of wireless technology with self-organizing and self-healing features for internet and real time applications, i.e., VoIP and Video over IP. Interoperability feature of WMNs have made them to integrate easily with other network technologies like wired networks, WiFi, WiMax, MANETs, and cellular networks. WMNs are gaining popularity due to their high network throughput which is highly depends on the routing procedures. Routing algorithms like optimized link state routing protocol and dynamic source routing make efficient routing decisions on the basis of routing metrics which actually predict the cost of link quality.
3 days ago by Springer Science+Business MediaResource Allocation for Clustered Network MIMO OFDMA Systems
In this paper, the authors address the resource allocation problem for the downlink of a large network multiple input multiple output orthogonal frequency division multiplexing system with 3-sector base stations. The system is statically divided into a number of disjoint clusters of sectors. A two-step resource allocation scheme is proposed involving the inter-cluster and the intra-cluster levels. As a first step or inter-cluster level, two cooperative frequency reuse approaches are designed to mitigate the inter-cluster interference. A user partition method is proposed to divide the users of each cluster into cluster-edge and cluster-center users.
6 days ago by Springer Science+Business MediaResidue Code Based Low Cost SEU-Tolerant FIR Filter Design for OBP Satellite Communication Systems
With the development of satellite communications, On-Board Processing (OBP) obtains more and more attentions due to the increased efficiency and performance. However, the large amounts of digital circuits in the OBP transponders are sensitive to the high-energy particles in space radiation environments, which may cause various kinds of single event effect. Among these effects, Single Event Upset (SEU) is the major potential reason for the instability of the satellite communication systems. Triple Modular Redundancy (TMR) is a classical and effective method for mitigating the SEU in digital circuits.
6 days ago by Springer Science+Business MediaA Limited Feedback Scheme Based on Spatially Correlated Channels for Coordinated Multipoint Systems
High spectral efficiency can be achieved in the downlink of multi-antenna coordinated multi-point systems provided that the multi-user interference is appropriately managed at the transmitter side. For this sake, down-link channel information needs to be sent back by the users, thus reducing the rate available at the up-link channel. The amount and type of feedback information required has been extensively studied and many limited feedback schemes have been proposed lately. A common pattern to all of them is that achieving low rates of feedback information is possible at the cost of increasing complexity at the user side and, sometimes, assuming that some statistics of the channel are known.
6 days ago by Springer Science+Business MediaA Cluster Based Proxy Mobile IPv6 for IP-WSNs
The Sensor Proxy Mobile IPv6 (SPMIPv6) has been designed for IP-based wireless sensor networks mobility to potentially save energy consumption by relieving the sensor nodes from participating in the handoff process. However, SPMIPv6 is dependent on a single and central Local Mobility Anchor (LMA), and thus, it inherited most of the problems observed in the Proxy Mobile IPv6 (PMIPv6) protocol, including long handoff latency, non-optimized communication path, and bottleneck issues. In addition, SPMIPv6 extends the single point of failure to include both the authentication and network information.
1 week ago by Springer Science+Business MediaEffect of Network Parameters on Neighbor Wireless Link Breaks in GPSR Protocol and Enhancement Using Mobility Prediction Model
The Greedy Perimeter Stateless Routing (GPSR) protocol is a well-known position-based routing protocol. Data packet routing in position-based routing protocols uses the neighbors' geographical position information, which is stored in the sender's neighbors list, and the destination's position information stored in the routing data packet header field to route the packet from source to destination. In the GPSR protocol, the sender routes the packets to a neighboring node, whose geographical position is the closest to the destination of all the sender's neighbors.
1 week ago by Springer Science+Business MediaSmarter Planet Leadership Series: Air Canada
Perfecting the art of self service. How self service helped an airline transform their brand.
1 week ago by IBMEvaluation of the Potential for Energy Saving in Macrocell and Femtocell Networks Using a Heuristic Introducing Sleep Modes in Base Stations
In mobile technologies two trends are competing. On the one hand, the mobile access network requires optimisation in energy consumption. On the other hand, data volumes and required bit rates are rapidly increasing. The latter trend requires the deployment of more dense mobile access networks as the higher bit rates are available at shorter distance from the base station. In order to improve the energy efficiency, the introduction of sleep modes is required. The authors derive a heuristic which allows establishing a baseline of active base station fractions in order to be able to evaluate mobile access network designs. They demonstrate that sleep modes can lead to significant improvements in energy efficiency and act as an enabler for femtocell deployments.
1 week ago by Springer Science+Business Media
