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

Massive multiple-input multiple-output (MIMO) wireless communications refers to the idea equipping cellular base stations (BSs) with a very large number of antennas, and has been shown to potentially allow for orders of magnitude improvement in spectral and energy efficiency using relatively simple (linear) processing. In this paper, we present a comprehensive overview of state-of-the-art research on the topic, which has recently attracted considerable attention. We begin with an information theoretic analysis to illustrate the conjectured advantages of massive MIMO, and then we address implementation issues related to channel estimation, detection and precoding schemes. We particularly focus on the potential impact of pilot contamination caused by the use of non-orthogonal pilot sequences by users in adjacent cells. We also analyze the energy efficiency achieved by massive MIMO systems, and demonstrate how the degrees of freedom provided by massive MIMO systems enable efficient single-carrier transmission. Finally, the challenges and opportunities associated with implementing massive MIMO in future wireless communications systems are discussed.

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An Overview of Massive MIMO: Benefits and Challenges

A system, method, apparatus and computer program product for providing location based functions and mobile e-commerce comprising a central processing unit including a processor, a storage device, and programming stored in the storage device, a display device, an audio input device, an audio output device, a communications module, a commerce module, an image module, and a location module. The programming controls the operation of the present invention to provide functions based on location data, to facilitate commercial exchanges by wirelessly exchanging payment and product information with venders, to identify services such as venders meeting selection criteria, to wirelessly exchange select information with other users and systems, to restrict and/or monitor the use of the device based on authorized user parameters, selecting one of a plurality networks through which to communicate, detecting a trigger for performing an action based on a change in location and sensed data, storing a voice annotation with a computer data file, determining service providers and associated communication parameters, contemporaneously maintaining a wireless voice and data link, providing a system for selecting and delivering mobile advertisements, and many other functions and services that are described herein.

System, method, and computer program product for providing location based services and mobile e-commerce

There is considerable pressure to define the key requirements of 5G, develop 5G standards, and perform technology trials as quickly as possible. Normally, these activities are best done in series but there is a desire to complete these tasks in parallel so that commercial deployments of 5G can begin by 2020. 5G will not be an incremental improvement over its predecessors; it aims to be a revolutionary leap forward in terms of data rates, latency, massive connectivity, network reliability, and energy efficiency. These capabilities are targeted at realizing high-speed connectivity, the Internet of Things, augmented virtual reality, the tactile internet, and so on. The requirements of 5G are expected to be met by new spectrum in the microwave bands (3.3-4.2 GHz), and utilizing large bandwidths available in mm-wave bands, increasing spatial degrees of freedom via large antenna arrays and 3-D MIMO, network densification, and new waveforms that provide scalability and flexibility to meet the varying demands of 5G services. Unlike the one size fits all 4G core networks, the 5G core network must be flexible and adaptable and is expected to simultaneously provide optimized support for the diverse 5G use case categories. In this paper, we provide an overview of 5G research, standardization trials, and deployment challenges. Due to the enormous scope of 5G systems, it is necessary to provide some direction in a tutorial article, and in this overview, the focus is largely user centric, rather than device centric. In addition to surveying the state of play in the area, we identify leading technologies, evaluating their strengths and weaknesses, and outline the key challenges ahead, with research test beds delivering promising performance but pre-commercial trials lagging behind the desired 5G targets.

5G : A tutorial overview of standards, trials, challenges, deployment, and practice

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

There are provided a method and device for transmitting/receiving reverse data rate information in a mobile communication system supporting multimedia service applications including voice and data services. According to the present invention, upon receipt of information about the maximum data rate of an SCH, a mobile station determines the minimum number of bits to be assigned to the reverse data rate information according to the number of data rates less than or equal to the maximum data rate and then transmits the reverse data rate information with the minimum number of bits to a base station.

Method and device for transmitting/receiving data rate information in a mobile communication system

Methods and apparatuses are provided for indicating a discovery signal resource by a User Equipment (UE) performing device-to-device communication. The UE receives information relating to the device-to-device communication from a base station. A synchronization signal including discovery signal-related information, is transmitted from the UE to a nearby UE, based on the information relating to the device-to-device communication. A discovery is performed based on the discovery signal-related information.

Method and apparatus for indicating discovery signal resources in device-to-device wireless communications

A method and apparatus for transmitting a broadcast physical layer packet in a mobile communication system supporting multi-slot transmission and hybrid Automatic Repeat Request (H-ARQ) are provided. The method comprises initially transmitting the broadcast physical layer packet according to a fixed transmission format for at least one first slot interval and retransmitting the broadcast physical layer packet for at least one second slot interval using a variable transmission format different from the transmission format used in the first slot interval.

Apparatus and method for transmitting/receiving broadcast data in a mobile communication system

A method and apparatus for transmitting and receiving forward channel status information in a multi-carrier mobile communication system. An MS transmits to a BS forward channel status information representing an average C/I of forward signals with respect to a plurality of carriers, the maximum of the forward signal C/Is, or each of the forward signal C/Is. The forward channel status information is absolute C/I information representing a current C/I, or relative C/I information representing a difference of the current C/I from a previous C/I.

Method and apparatus for transmitting and receiving information about forward channel status in a multi-carrier mobile communication system

A method and an apparatus for transmitting/receiving feedback in a mobile communication system are provided. A method of configuring and receiving feedback information of an evolved Node B (eNB) includes transmitting configuration information on a plurality of reference signals including a first reference signal and a second reference signal to a User Equipment (UE); transmitting feedback configuration information including first feedback configuration information on the first reference signal and second feedback configuration information configured such that feedback information on the second reference signal is generated with reference to the first feedback configuration information to the UE; transmitting the reference signal to the UE according to the configuration information on the reference signal; and receiving feedback information including first feedback information according to the first feedback configuration information and second feedback information according to the second feedback configuration information from the UE.

Younsun Kim

Papers

Method and device for transmitting/receiving data rate information in a mobile communication system

Method and apparatus for indicating discovery signal resources in device-to-device wireless communications

Apparatus and method for transmitting/receiving broadcast data in a mobile communication system

Method and apparatus for transmitting and receiving information about forward channel status in a multi-carrier mobile communication system

Method and apparatus for transmitting and receiving feedback information in mobile communication system using multiple antennas