The fifth generation (5G) wireless network technology is to be standardized by 2020, where main goals are to improve capacity, reliability, and energy efficiency, while reducing latency and massively increasing connection density. An integral part of 5G is the capability to transmit touch perception type real-time communication empowered by applicable robotics and haptics equipment at the network edge. In this regard, we need drastic changes in network architecture including core and radio access network (RAN) for achieving end-to-end latency on the order of 1 ms. In this paper, we present a detailed survey on the emerging technologies to achieve low latency communications considering three different solution domains: 1) RAN; 2) core network; and 3) caching. We also present a general overview of major 5G cellular network elements such as software defined network, network function virtualization, caching, and mobile edge computing capable of meeting latency and other 5G requirements.

A Survey on Low Latency Towards 5G: RAN, Core Network and Caching Solutions

The present invention is designed to provide a user terminal, a radio base station and a radio communication method of novel structures that can achieve a good communication environment. A radio base station non-orthogonal-multiplexes downlink signals for a plurality of user terminals over a given radio resource, a user terminal having received the downlink signals for the plurality of user terminals decodes downlink signal for another user terminal, judges whether or not the downlink signal for the other user terminal has been successfully received, based on the decoding result of the downlink signal, reports a judgement result as to whether or not the downlink signal for the other user terminal has been successfully received and a judgement result as to whether or not a downlink signal for the user terminal has been successfully received, to the radio base station, and then the radio base station executes retransmission control of downlink signals based on reports from the user terminal.

User terminal, radio base station and radio communication method

In order that a user terminal properly identifies a connection cell in a radio communication system (LTE-U) for operating LTE in an unlicensed band, a user terminal for communicating with a radio base station in an unlicensed band is provided with a detection section that detects a synchronization signal transmitted from a radio base station using a dummy cell ID used in common among a plurality of radio base stations, an estimation section that performs channel estimation using a reference signal, and a reception processing section that performs reception processing of system information transmitted from a radio base station using a channel estimation result.

User terminal, wireless base station, and wireless communication method

Tactile Internet (TI) is envisioned to create a paradigm shift from the content-oriented communications to steer/control-based communications by enabling real-time transmission of haptic information (i.e., touch, actuation, motion, vibration, surface texture) over Internet in addition to the conventional audiovisual and data traffics. This emerging TI technology, also considered as the next evolution phase of Internet of Things (IoT), is expected to create numerous opportunities for technology markets in a wide variety of applications ranging from teleoperation systems and Augmented/Virtual Reality (AR/VR) to automotive safety and eHealthcare towards addressing the complex problems of human society. However, the realization of TI over wireless media in the upcoming Fifth Generation (5G) and beyond networks creates various non-conventional communication challenges and stringent requirements in terms of ultra-low latency, ultra-high reliability, high data-rate connectivity, resource allocation, multiple access and quality-latency-rate tradeoff. To this end, this paper aims to provide a holistic view on wireless TI along with a thorough review of the existing state-of-the-art, to identify and analyze the involved technical issues, to highlight potential solutions and to propose future research directions. First, starting with the vision of TI and recent advances and a review of related survey/overview articles, we present a generalized framework for wireless TI in the Beyond 5G Era including a TI architecture, the main technical requirements, the key application areas and potential enabling technologies. Subsequently, we provide a comprehensive review of the existing TI works by broadly categorizing them into three main paradigms; namely, haptic communications, wireless AR/VR, and autonomous, intelligent and cooperative mobility systems. Next, potential enabling technologies across physical/Medium Access Control (MAC) and network layers are identified and discussed in detail. Also, security and privacy issues of TI applications are discussed along with some promising enablers. Finally, we present some open research challenges and recommend promising future research directions.

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Toward Tactile Internet in Beyond 5G Era: Recent Advances, Current Issues, and Future Directions

A method for transmitting and receiving data in a wireless communication system and an apparatus for the method are disclosed. More specifically, The present invention provides a method for transmitting downlink data in a wireless communication system can comprise mapping, by a eNB, first downlink data into a physical downlink shared channel (PDSCH) region according to a radio frame structure based on a first transmission time interval (TTI), mapping, by the eNB, second downlink data to a short PDSCH (sPDSCH) region according to a radio frame structure based on a second TTI, and transmitting, by the eNB, the first and the second downlink data.

Method for transmitting and receiving data in wireless communication system and apparatus for the same

Content sharing among users by utilizing device-to-device (D2D) multicast communications is one of the attractive solutions for mobile traffic offloading. By sharing content among other nearby users, repeated downloads of the same network data can be reduced. To achieve efficient sharing of content among users, selection of the transmit (Tx) users who distribute content to others is important. In this paper, we propose an efficient Tx user selection algorithm, which improves system capacity while minimizing the impact of interference among D2D multicast communications. The effectiveness of the proposed algorithm is shown through system-level simulation in comparison with conventional schemes. The results showed that when compared with the conventional scheme, an improvement in 5%-tile edge user throughput of more than 50% could be obtained while system capacity degradation was kept at 13%.

A User Selection Algorithm for D2D Multicast Communication Underlaying Cellular Systems

LTE/WiGig RAN-Level Interworking Architecture for 5G Millimeter-Wave Heterogeneous Networks

LTE-WLAN aggregation architecture, which is under discussion in the 3GPP Release-13, can be extended to LTE-WiGig aggregation provided the millimeter-wave (mm-wave) small cell discovery and beamforming (BF) mechanism can be redesigned for the application of this aggregation architecture. In this paper, we propose a novel macro-controlled BF protocol using mm-wave beam databases for LTE-WiGig aggregation in mm-wave heterogeneous networks. This protocol enables an mm-wave access point (AP) to communicate with user equipment (UE) using the best beam under the control of LTE macro eNBs (evolved Node B). In this protocol, the locations of UEs and mm-wave beam information, including mm-wave AP identification (ID), beam ID, received beam power, etc., are collected by UEs and sent to LTE eNBs. LTE eNBs process all the data and construct the location and mm-wave beam databases for all mm-wave APs. Therefore, just by matching the current UE location with the pre-stored information in the databases, the LTE eNBs can allocate the best mm-wave AP and its best beam to the UE at its current location. Simulation results show that the proposed protocol can select the best beam with more than 90% accuracy and achieve more than 18% higher average throughput when the size of the databases is large enough compared to the exhaustive searching scheme due to the decrease in setup time.

Macro-Controlled Beam Database-Based Beamforming Protocol for LTE-WiGig Aggregation in Millimeter-Wave Heterogeneous Networks

In this paper, a fast outer-loop link adaptation (OLLA) scheme is proposed to realize low-latency transmission. OLLA generally compensates for the estimated signal-to-interference-plus-noise ratio (SINR) that is used to optimize the selection of a modulation and coding scheme (MCS) based on the reception of a positive acknowledgement (ACK) or a negative acknowledgement (NAK) for a Hybrid ARQ (HARQ) initial transmission. The proposed scheme controls the size of the compensation in the estimated SINR based on the time elapsed after a user equipment (UE) transits from an idle state to an active state. The computer simulation result shows that the proposed scheme can achieve a high throughput just after UE starts its data transmission that is otherwise impossible if using the conventional scheme. This performance helps shorten the latency of transmission, especially in small-packet applications.

Fast outer-loop link adaptation scheme realizing low-latency transmission in LTE-Advanced and future wireless networks

A base station device (E-UTRAN) assigns a frequency band unsupported by the base station device as a radio resource usable for terminal-to-terminal communication, and transmits resource information for designating the assigned radio resource to a first terminal device and a second terminal device.

Suegara Yasuhiro

Papers

A User Selection Algorithm for D2D Multicast Communication Underlaying Cellular Systems

LTE/WiGig RAN-Level Interworking Architecture for 5G Millimeter-Wave Heterogeneous Networks

Macro-Controlled Beam Database-Based Beamforming Protocol for LTE-WiGig Aggregation in Millimeter-Wave Heterogeneous Networks

Fast outer-loop link adaptation scheme realizing low-latency transmission in LTE-Advanced and future wireless networks

Radio control device, terminal device and communication method