There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Statistics for Spatial Data.

This chapter contains sections titled: Overview MAC convergence sublayer MAC common part sublayer MAC security sublayer MAC enhancements for 2-11 GHz operation IEEE 802.16 physical layers Coexistence BWA business and technology trends

Air Interface for Fixed Broadband Wireless Access Systems

Author(s): Shehabi, Arman; Smith, Sarah; Sartor, Dale; Brown, Richard; Herrlin, Magnus; Koomey, Jonathan; Masanet, Eric; Horner, Nathaniel; Azevedo, Ines; Lintner, William

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United States Data Center Energy Usage Report

5G network slicing using SDN and NFV: A survey of taxonomy, architectures and future challenges

The CPRI specification has been introduced to enable the communication between radio equipment and radio equipment controllers, and is of particular interest for mobile operators willing to deploy their networks following the novel cloud radio access network approach. In such a case, CPRI provides an interface for the interconnection of remote radio heads with a baseband unit by means of the so-called fronthaul network. This article presents the CPRI specification, its concept, design, and interfaces, provides a use case for fronthaul dimensioning in a realistic LTE scenario, and proposes some interesting open research challenges in the next-generation 5G mobile network.

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An overview of the CPRI specification and its application to C-RAN-based LTE scenarios

Until very recently, energy efficiency has received little attention in many wired communications environments. For example, in most current Ethernet standards the transmitter and receiver operate at full power even when no data is being sent. However, new upcoming energy-aware standards, such as Energy Efficient Ethernet (EEE), are addressing this issue by introducing a low power mode for idle link intervals. The future EEE standard defines the procedure to enter and exit the low power mode. With EEE the actual energy savings will depend on the amount of traffic and on the timing of the frame arrivals. In this paper the performance of EEE in terms of energy saving is evaluated. The results show that although EEE improves the energy efficiency, there is still potential for substantial further energy savings as in many cases most of the energy is wasted in waking up and sleeping the link.

Performance evaluation of energy efficient ethernet

The proposed Energy-Efficient Ethernet (EEE) standard reduces energy consumption by defining two operation modes for transmitters and receivers: active and low power. Burst transmission can provide additional energy savings when EEE is used. Collecting data frames into large-sized data bursts for back-to-back transmission maximizes the time an EEE device spends in low power, thus making its consumption nearly proportional to its traffic load. An initial evaluation shows that the additional savings in the scenarios considered range from 5 to 70 percent for conventional users and approximately 50 percent for large data centers.

Burst Transmission for Energy-Efficient Ethernet

Enabling the transport of fronthaul traffic in next-generation cellular networks [fifth-generation (5G)] following the cloud radio access network (C-RAN) architecture requires a redesign of the fronthaul network featuring high capacity and ultra-low latency. With the aim of leveraging statistical multiplexing gains, infrastructure reuse, and, ultimately, cost reduction, the research community is focusing on Ethernet-based packet-switch networks. To this end, we propose using the high queuing delay percen-tiles of the G/G/1 queuing model as the key metric in front-haul network dimensioning. Simulations reveal that Kingman's exponential law of congestion provides accurate estimates on such delays for the particular case of aggregating a number of evolved Common Public Radio Interface fronthaul flows, namely functional splits and II D . We conclude that conventional 10 G, 40 G, and 100 G transponders can cope with multiple legacy 10–20 MHz radio channels with worst-case delay guarantees. Conversely, scaling to 40 and 100 MHz channels will require the introduction of 200G, 400G, and even 1T high-speed transponders.

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David Larrabeiti

Papers

An overview of the CPRI specification and its application to C-RAN-based LTE scenarios

Performance evaluation of energy efficient ethernet

Burst Transmission for Energy-Efficient Ethernet

Fronthaul network modeling and dimensioning meeting ultra-low latency requirements for 5G

Towards an energy efficient 10 Gb/s optical ethernet: Performance analysis and viability