What will 5G be? What it will not be is an incremental advance on 4G. The previous four generations of cellular technology have each been a major paradigm shift that has broken backward compatibility. Indeed, 5G will need to be a paradigm shift that includes very high carrier frequencies with massive bandwidths, extreme base station and device densities, and unprecedented numbers of antennas. However, unlike the previous four generations, it will also be highly integrative: tying any new 5G air interface and spectrum together with LTE and WiFi to provide universal high-rate coverage and a seamless user experience. To support this, the core network will also have to reach unprecedented levels of flexibility and intelligence, spectrum regulation will need to be rethought and improved, and energy and cost efficiencies will become even more critical considerations. This paper discusses all of these topics, identifying key challenges for future research and preliminary 5G standardization activities, while providing a comprehensive overview of the current literature, and in particular of the papers appearing in this special issue.

What Will 5G Be

Statistics for Spatial Data.

An introduction to heat transfer

Cloud Radio Access Network (C-RAN) is a novel mobile network architecture which can address a number of challenges the operators face while trying to support growing end-user's needs. The main idea behind C-RAN is to pool the Baseband Units (BBUs) from multiple base stations into centralized BBU Pool for statistical multiplexing gain, while shifting the burden to the high-speed wireline transmission of In-phase and Quadrature (IQ) data. C-RAN enables energy efficient network operation and possible cost savings on baseband resources. Furthermore, it improves network capacity by performing load balancing and cooperative processing of signals originating from several base stations. This paper surveys the state-of-the-art literature on C-RAN. It can serve as a starting point for anyone willing to understand C-RAN architecture and advance the research on C-RAN.

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Cloud RAN for Mobile Networks—A Technology Overview

International Technology Roadmap for Semiconductors 2003の要求清浄度について － シリコンウエハ表面と雰囲気環境に要求される清浄度, 分析方法の現状について －

The Internet of Things (IoT) is defined as a paradigm in which objects equipped with sensors, actuators, and processors communicate with each other to serve a meaningful purpose. In this paper, we survey state-of-the-art methods, protocols, and applications in this new emerging area. This survey paper proposes a novel taxonomy for IoT technologies, highlights some of the most important technologies, and profiles some applications that have the potential to make a striking difference in human life, especially for the differently abled and the elderly. As compared to similar survey papers in the area, this paper is far more comprehensive in its coverage and exhaustively covers most major technologies spanning from sensors to applications.

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Internet of Things: Architectures, Protocols, and Applications

Within-die parameter variation poses a major challenge to high-performance microprocessor design, negatively impacting a processor's frequency and leakage power. Addressing this problem, this paper proposes a microarchitecture-aware model for process variation-including both random and systematic effects. The model is specified using a small number of highly intuitive parameters. Using the variation model, this paper also proposes a framework to model timing errors caused by parameter variation. The model yields the failure rate of microarchitectural blocks as a function of clock frequency and the amount of variation. With the combination of the variation model and the error model, we have VARIUS, a comprehensive model that is capable of producing detailed statistics of timing errors as a function of different process parameters and operating conditions. We propose possible applications of VARIUS to microarchitectural research.

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VARIUS: A Model of Process Variation and Resulting Timing Errors for Microarchitects

Process variation affects processor pipelines by making some stages slower and others faster, therefore exacerbating pipeline unbalance. This reduces the frequency attainable by the pipeline. To improve performance, this paper proposes ReCycle, an architectural framework that comprehensively applies cycle time stealing to the pipeline - transferring the time slack of the faster stages to the slow ones by skewing clock arrival times to latching elements after fabrication. As a result, the pipeline can be clocked with a period equal to the average stage delay rather than the longest one. In addition, ReCycle's frequency gains are enhanced with Donor stages, which are empty stages added to "donate" slack to the slow stages. Finally, ReCycle can also convert slack into power reductions.For a 17FO4 pipeline, ReCycle increases the frequency by 12% and the application performance by 9% on average. Combining ReCycle and donor stages delivers improvements of 36% in frequency and 15% in performance onaverage, completely reclaiming the performance losses due to variation.

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ReCycle: pipeline adaptation to tolerate process variation

The mobile Internet has seen tremendous progress due to the standardization efforts around WiMAX, LTE and beyond. There are also early trends towards adoption of software radio and a growing presence of general purpose platforms in wireless networking. Such platforms are programmer-friendly and with recent advances on multi-core and hybrid architectures, allow signal processing, network processor class packet processing, wire-speed computation and server-class virtualization capabilities for software radio realizations of 3G and 4G wireless stacks. Software radio over IT platforms will enable the virtualization of base stations and consolidation of virtual base stations into central pools (a local "cloud site") with fiber connectivity to towers, which we call a Wireless Network Cloud (WNC). A Virtual base station (BS) pool supporting multiple BS software instances over a general OS and IT platform is an important step towards the realization of the larger WNC concept. This paper introduces the first TDD WiMAX SDR BS implemented on a commodity server, in conjunction with a novel design of a remote radio head (RRH). We also present the first working prototype of a virtual BS (VBS) pool, exploring the systems challenges in supporting a VBS pool on multi-core IT platforms. The results from our VBS pool prototype for WiMAX verify that these solutions can meet system requirements including synchronization, latency and jitter.

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Virtual base station pool: towards a wireless network cloud for radio access networks

Parameter variation in integrated circuits causes sections of a chip to be slower than others. If, to prevent any resulting timing errors, we design processors for worst-case parameter values, we may lose substantial performance. An alternate approach explored in this paper is to design for closer to nominal values, and provide some transistor budget to tolerate unavoidable variation-induced errors. To assess this approach, this paper first presents a novel framework that shows how microarchitecture techniques can trade off variation-induced errors for power and processor frequency. Then, the paper introduces an effective technique to maximize performance and minimize power in the presence of variation-induced errors, namely High-Dimensional dynamic adaptation. For efficiency, the technique is implemented using a machine-learning algorithm. The results show that our best configuration increases processor frequency by 56% on average, allowing the processor to cycle 21% faster than without variation. Processor performance increases by 40% on average, resulting in a performance that is 14% higher than without variation - at only a 10.6% area cost.

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Smruti R. Sarangi

Papers

Internet of Things: Architectures, Protocols, and Applications

VARIUS: A Model of Process Variation and Resulting Timing Errors for Microarchitects

ReCycle: pipeline adaptation to tolerate process variation

Virtual base station pool: towards a wireless network cloud for radio access networks

EVAL: Utilizing processors with variation-induced timing errors