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

An apparatus and method for transmitting/receiving a PDCCH (Packet Data Control Channel) for efficient packet data transmission in a communication system supporting packet data service. To allow both TDM-transmission and TDM/CDM-transmission of packet data, PDCCHs having different control information are transmitted. A 1PDCCH and a 2PDCCH are selectively transmitted according to the channel environments of users to thereby minimize the transmission power of the 1PDCCH and the 2PDCCH. A PDCCH receiver receives the 1PDCCH and the 2PDCCH using Walsh functions assigned to them, demodulates them, and checks errors in them, thereby obtaining control information about packet data to be received.

Apparatus for transmitting/receiving data on packet data control channel in a communication system

A power controlling apparatus and method in a mobile communication system. A receiver in a mobile station multiplexes the frame reception result indicator bits for at least two traffic channels received from a transmitter in a base station, inserts the multiplexed frame reception result indicator bits in a pilot signal bit by bit, and transmits the reverse frame. Then, the transmitter extracts the pilot signal from the reverse frame, demultiplexes the frame reception result indicator bits, and performs a power control on the traffic channels based on the values of the frame reception result indicator bits.

Power controlling apparatus and method in mobile communication system

A method and an apparatus are provided for transmitting and receiving control information in wireless communication system. An eNB generates control information, and transmits the control information using at least one enhanced Control Channel Element (eCCE) and at least one antenna port. The at least one antenna port is determined according to at least one of a starting index of the at least one eCCE and an aggregation level of the at least one eCCE.

Method and apparatus for transmitting and receiving control information in a wireless communication system

In this paper, we study practical 2-Dimensional (2D) active antenna array configurations for Massive MIMO systems and evaluate the system-level performance with the form factor at the base stations operating in cellular frequency band. To this end, we develop a 3-Dimensional Spatial Channel Model (3D SCM) to facilitate accurate performance evaluation and to build insights for system design. System-level simulation is conducted for various 2D antenna array configurations (8Hx8V, 8Hx4V) by using the 3D SCM developed. Simulation results show that 2–5 times cell average throughput gain and 1.5–9 times cell edge throughput gain can be achieved compared to the 4G LTE system.

Fulfilling the promise of massive MIMO with 2D active antenna array

A feedback information transmission/reception method for use in a mobile communication system is provided. The feedback information transmission method includes receiving configuration information on at least two reference signals and feedback configuration information for use in generating feedback information based on the at least two reference signals from a base station, receiving the at least two reference signals from the base station, measuring the at least two reference signals received, generating the feedback information based on the measurement result according to the feedback configuration information, and transmitting the feedback information to the base station.

Younsun Kim

Papers

Apparatus for transmitting/receiving data on packet data control channel in a communication system

Power controlling apparatus and method in mobile communication system

Method and apparatus for transmitting and receiving control information in a wireless communication system

Fulfilling the promise of massive MIMO with 2D active antenna array

Method and apparatus for transmitting and receiving feedback information in mobile communication system based on 2 dimensional massive mimo