Showing papers by "NTT DoCoMo published in 2017"

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

Abstract: 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.

On the Metabolism of Exogenous Ketones in Humans.

Abstract: Background and aims: Currently there is considerable interest in ketone metabolism owing to recently reported benefits of ketosis for human health. Traditionally, ketosis has been achieved by following a high-fat, low-carbohydrate ‘ketogenic’ diet, but adherence to such diets can be difficult. An alternative way to increase blood D-β-hydroxybutyrate (D-βHB) concentrations is ketone drinks, but the metabolic effects of exogenous ketones are relatively unknown. Here, healthy human volunteers took part in three randomized metabolic studies of drinks containing a ketone ester (KE); (R)-3-hydroxybutyl-(R)-1,3-hydroxybutyrate, or ketone salts (KS); sodium plus potassium βHB. Methods and Results: In the first study, 15 participants consumed KE or KS drinks that delivered ~12 g or ~24 g of βHB. Both drinks elevated blood D-βHB concentrations (D-βHB Cmax: KE 2.8 mM, KS 1.0 mM, P < 0.001), which returned to baseline within 3-4 h. KS drinks were found to contain 50% of the L-βHB isoform, which remained elevated in blood for over 8 h, but was not detectable after 24 h. Urinary excretion of both D-βHB and L-βHB was < 1.5 % of the total βHB ingested and was in proportion to the blood AUC. D-βHB, but not L-βHB, was slowly converted to breath acetone. The KE drink decreased blood pH by 0.10 and the KS drink increased urinary pH from 5.7 to 8.5. In the second study, the effect of a meal before a KE drink on blood D-βHB concentrations was determined in 16 participants. Food lowered blood D-βHB Cmax by 33% (Fed 2.2 mM, Fasted 3.3 mM, P < 0.001), but did not alter acetoacetate or breath acetone concentrations. All ketone drinks lowered blood glucose, free fatty acid and triglyceride concentrations, and had similar effects on blood electrolytes, which remained normal. In the final study, participants were given KE over 9 h as three drinks (n = 12) or a continuous nasogastric infusion (n = 4) to maintain blood D-βHB concentrations greater than 1 mM. Both drinks and infusions gave identical D-βHB AUC of 1.3-1.4 moles.min. Conclusion: We conclude that exogenous ketone drinks are a practical, efficacious way to achieve ketosis.

User terminal and wireless communication method

Abstract: This user terminal is characterized by having: a transmission unit that uses an uplink control channel resource in a prescribed bandwidth part (BWP) and sends uplink control information; and a control unit that determines the correspondence between said uplink control channel resource and a prescribed index, on the basis of prescribed information, and specifies the uplink control channel resource. As a result of the present invention, reduction in communication throughput can be suppressed even when performing control on the basis of BWP.

5G Field Trials: OFDM-Based Waveforms and Mixed Numerologies

Abstract: Service diversity is expected in the upcoming fifth-generation (5G) cellular networks, which poses great challenges to the underlying waveforms to accommodate heterogeneous service requirements in a flexible way. By dividing the bandwidth into several subbands, each having a different numerology, this paper reports a field trial in time division duplex downlink conducted on a configurable test bed in a real-world environment for the performance evaluations of orthogonal frequency-division multiplexing (OFDM)-based 5G waveform candidates, i.e., cyclically prefixed OFDM (CP-OFDM), windowing OFDM (W-OFDM), and filtered OFDM (f-OFDM), in the presence of mixed numerologies. Field trial results confirm the feasibility of mixed numerologies and reveal the impact of several important system parameters, e.g., guard bandwidth, data bandwidth, signal-to-noise ratio (SNR), and transmit power. The results also suggest that f-OFDM outperforms CP-OFDM and W-OFDM in terms of both the spectrum efficiency and robustness in a high SNR regime, and the gain increases with a higher inter-numerology out-of-band interference. In some specific scenarios, ideal spectrum utilization can be realized by f-OFDM which completely removes the guard band.

Licensed-Assisted Access to Unlicensed Spectrum in LTE Release 13

Abstract: Exploiting the unlicensed spectrum is considered by 3GPP as one promising solution to meet ever-increasing traffic growth. As a result, one major enhancement for LTE in Release 13 has been to enable its operation in the unlicensed spectrum via licensed-assisted access (LAA). In this article, we provide an overview of the Release 13 LAA technology including motivation, use cases, LTE enhancements for enabling the unlicensed band operation, and the coexistence evaluation results contributed by 3GPP participants.

Spectral Efficiency Improvement With 5G Technologies: Results From Field Tests

Abstract: Spectral efficiency is always a key factor to be improved and optimized along mobile communication networks evolving generation by generation. 5G enabling technologies must take spectral efficiency into consideration. In this paper, we show the performance of three key 5G technologies in sense of spectral efficiency improvement. Sparse code multiple access, polar codes, and filtered orthogonal frequency-division multiplexing are novel multiple access technology, channel coding scheme, and waveform, respectively. The combination of them is implemented in a 5G field trial testbed by NTT DOCOMO and Huawei for the first time. According to the field test results, we achieve over 100% spectral efficiency improvement comparison with baseline, where orthogonal frequency-division multiple access and turbo coding as LTE are used.

On Heterogeneous Coded Distributed Computing

Abstract: We consider the recently proposed Coded Distributed Computing (CDC) framework [1]-[3] that leverages carefully designed redundant computations to enable coding opportunities that substantially reduce the communication load of distributed computing. We generalize this framework to heterogeneous systems where different nodes in the computing cluster can have different storage (or processing) capabilities. We provide the information-theoretically optimal data set placement and coded data shuffling scheme that minimizes the communication load in a cluster with 3 nodes. For clusters with K > 3 nodes, we provide an algorithm description to generalize our coding ideas to larger networks.

User equipment, feedback control method, and retransmission control method

Abstract: A user device used as a reception-side user device in a mobile communications system supporting D2D communications, comprising: a feedback means that receives a D2D signal from a transmission-side user device and sends a feedback signal for the D2D signal, to the transmission-side user device, by using a prescribed resource; and a reception means that receives a retransmitted D2D signal transmitted from the transmission-side user device, on the basis of the feedback signal.

Resource and Mobility Management in the Network Layer of 5G Cellular Ultra-Dense Networks

Abstract: The provision of very high capacity is one of the big challenges of the 5G cellular technology. This challenge will not be met using traditional approaches like increasing spectral efficiency and bandwidth, as witnessed in previous technology generations. Cell densification will play a major role thanks to its ability to increase the spatial reuse of the available resources. However, this solution is accompanied by some additional management challenges. In this article, we analyze and present the most promising solutions identified in the METIS project for the most relevant network layer challenges of cell densification: resource, interference and mobility management.

iSphere: Self-Luminous Spherical Drone Display

Abstract: We present iSphere, a flying spherical display that can display high resolution and bright images in all directions from anywhere in 3D space. Our goal is to build a new platform which can physically and directly emerge arbitrary bodies in the real world. iSphere flies by itself using a built-in drone and creates a spherical display by rotating arcuate multi light-emitting diode (LED) tapes around the drone. As a result of the persistence of human vision, we see it as a spherical display flying in the sky. The proposed method yields large display surfaces, high resolution, drone mobility, high visibility and 360° field of view. Previous approaches fail to match these characteristics, because of problems with aerodynamics and payload. We construct a prototype and validate the proposed method. The unique characteristics and benefits of flying spherical display surfaces are discussed and we describe application scenarios based on iSphere such as guidance, signage and telepresence.

On Heterogeneous Coded Distributed Computing

Abstract: We consider the recently proposed Coded Distributed Computing (CDC) framework that leverages carefully designed redundant computations to enable coding opportunities that substantially reduce the communication load of distributed computing. We generalize this framework to heterogeneous systems where different nodes in the computing cluster can have different storage (or processing) capabilities. We provide the information-theoretically optimal data set placement and coded data shuffling scheme that minimizes the communication load in a cluster with 3 nodes. For clusters with $K>3$ nodes, we provide an algorithm description to generalize our coding ideas to larger networks.

Testing the Feasibility and Usability of a Novel Smartphone-Based Self-Management Support System for Dialysis Patients: A Pilot Study

Abstract: Background: Diet and fluid restrictions that need continuous self-management are among the most difficult aspects of dialysis treatment. Smartphone applications may be useful for supporting self-management. Objective: Our objective is to investigate the feasibility and usability of a novel smartphone-based self-management support system for dialysis patients. Methods: We developed the Self-Management and Recording System for Dialysis (SMART-D), which supports self-monitoring of three mortality-related factors that can be modified by lifestyle: interdialytic weight gain and predialysis serum potassium and phosphorus concentrations. Data is displayed graphically, with all data evaluated automatically to determine whether they achieve the values suggested by the Japanese Society for Dialysis Therapy guidelines. In a pilot study, 9 dialysis patients used SMART-D system for 2 weeks. A total of 7 of them completed questionnaires rating their assessment of SMART-D’s usability and their satisfaction with the system. In addition, the Kidney Disease Quality of Life scale was compared before and after the study period. Results: All 9 participants were able to use SMART-D with no major problems. Completion rates for body weight, pre- and postdialysis weight, and serum potassium and phosphorus concentrations were, respectively, 89% (SD 23), 95% (SD 7), and 78% (SD 44). Of the 7 participants who completed the usability survey, all were motivated by the sense of security derived from using the system, and 6 of the 7 (86%) reported that using SMART-D helped improve their lifestyle and self-management. Conclusions: Using SMART-D was feasible, and the system was well regarded by patients. Further study with larger scale cohorts and longer study and follow-up periods is needed to evaluate the effects of SMART-D on clinical outcomes and quality of life. [JMIR Res Protoc 2017;6(4):e63]

Non-orthogonal multiple access for mmWave drones with multi-antenna transmission

Abstract: Unmanned aerial vehicles (UAVs) can be deployed as aerial base stations (BSs) for rapid establishment of communication networks during temporary events and after disasters. Since UAV-BSs are low power nodes, achieving high spectral and energy efficiency are of paramount importance. In this paper, we introduce non-orthogonal multiple access (NOMA) transmission for millimeter-wave (mmWave) drones serving as flying BSs at a large stadium potentially with several hundreds or thousands of mobile users. In particular, we make use of multi-antenna techniques specifically taking into consideration the physical constraints of the antenna array, to generate directional beams. Multiple users are then served within the same beam employing NOMA transmission. If the UAV beam can not cover entire region where users are distributed, we introduce beam scanning to maximize outage sum rates. The simulation results reveal that, with NOMA transmission the spectral efficiency of the UAV based communication can be greatly enhanced compared to orthogonal multiple access (OMA) transmission. Further, the analysis shows that there is an optimum transmit power value for NOMA beyond which outage sum rates do not improve further.

A Fast Estimation Technique for Evaluating the Specific Absorption Rate of Multiple-Antenna Transmitting Devices

Abstract: In this paper, we present a fast technique for estimating the specific absorption rate (SAR) of multiple-antenna transmitting devices such as mobile phones, which utilize two or more antennas in communication. SAR values for arbitrary relative phase combinations of the antennas at an observation point can be estimated from SAR measurements for several known relative phases at the same observation point. Several numerical and experimental validations on different antenna configurations and operating frequencies have been carried out to verify the proposed estimation method. It has been highlighted that the proposed estimation method is simple yet provides highly accurate estimated SAR values.

5G Field Experimental Trials on URLLC Using New Frame Structure

Abstract: The fifth generation mobile communications (5G) system will need to support ultra-reliable and low-latency communications (URLLC) to enable future mission-critical applications, eg, self-driving cars and remote control With the aim to verify the feasibility of URLLC related 5G requirements under real environments, field experimental trials of URLLC using new frame structure were conducted in Yokohama, Japan In this paper, we present the trial results and investigate the impact of 5G new frame structure and retransmission method on URLLC performance To reduce the user-plane latency and improve the packet success probability, a 60-kHz subcarrier spacing, self-contained frame structure and acknowledgement/negative acknowledgement-less (ACK/NACK-less) retransmission are adopted We test these techniques in real field using our prototype test-bed The field trial results show that the URLLC related requirements defined by 3GPP are achieved even for a low signal-to-noise ratio or non-line-of-sight locations

Derivation of Coupling Factors for Different Wireless Power Transfer Systems: Inter- and Intralaboratory Comparison

Abstract: In this study, the inter- and intralaboratory comparison of coupling factors is discussed for human exposure to nonuniform magnetic field from different wireless power transfer (WPT) systems. In order to derive the coupling factors, different laboratories computed the internal electric field and specific absorption rate (SAR) for different WPT configurations. The concept of coupling factors was originally introduced in the International Electrotechnical Commission (IEC) 62311 and 62233 standards, for product safety assessment. For WPT systems, extension of the coupling factors is discussed in the IEC working group. This factor enables the estimation of the internal electric field and the SAR without detailed computation using human anatomical models. The coupling factors were computed for different WPT systems, such as an electric vehicle charging at approximately 100 kHz, induction coupling systems (140 kHz band), and home appliances (6.78 MHz). Four in-house codes were used in this inter- and intralaboratory comparison study to compute the coupling factors for the systems. Similar tendencies were observed in the coupling factors obtained by the groups. The difference between the coupling factors of different research groups is 30% when considering the same exposure scenarios. The coupling factors for different WPT systems are different because of the frequency, coil size, and existence of the magnetic sheet (shield). The variability of the internal electric field for WPT systems is also investigated to set the coupling factor required for practical use.

A Survey of Efficient Ray-Tracing Techniques for Mobile Radio Propagation Analysis

Abstract: With the advances in computer processing that have yielded an enormous increase in performance, numerical analytical approaches based on electromagnetic theory have recently been applied to mobile radio propagation analysis. One such approach is the ray-tracing method based on geometrical optics and the uniform geometrical theory of diffraction. In this paper, ray-tracing techniques that have been proposed in order to improve computational accuracy and speed are surveyed. First, imaging and ray-launching methods are described and their extended methods are surveyed as novel fundamental ray-tracing techniques. Next, various ray-tracing acceleration techniques are surveyed and categorized into three approaches, i.e., deterministic, heuristic, and brute force. Then, hybrid methods are surveyed such as those employing Physical optics, the Effective Roughness model, and the Finite-Difference Time-Domain method that have been proposed in order to improve analysis accuracy. key words: ray-tracing, acceleration technique, hybrid model, mobile radio propagation

Non-Orthogonal Multiple Access for mmWave Drones with Multi-Antenna Transmission

Abstract: Unmanned aerial vehicles (UAVs) can be deployed as aerial base stations (BSs) for rapid establishment of communication networks during temporary events and after disasters. Since UAV-BSs are low power nodes, achieving high spectral and energy efficiency are of paramount importance. In this paper, we introduce non-orthogonal multiple access (NOMA) transmission for millimeter-wave (mmWave) drones serving as flying BSs at a large stadium potentially with several hundreds or thousands of mobile users. In particular, we make use of multi-antenna techniques specifically taking into consideration the physical constraints of the antenna array, to generate directional beams. Multiple users are then served within the same beam employing NOMA transmission. If the UAV beam can not cover entire region where users are distributed, we introduce beam scanning to maximize outage sum rates. The simulation results reveal that, with NOMA transmission the spectral efficiency of the UAV based communication can be greatly enhanced compared to orthogonal multiple access (OMA) transmission. Further, the analysis shows that there is an optimum transmit power value for NOMA beyond which outage sum rates do not improve further.

Directional training and fast sector-based processing schemes for mmWave channels

Abstract: We consider a single-cell scenario involving a single base station (BS) with a massive array serving multi-antenna terminals in the downlink of a mmWave channel. We present a class of multiuser MIMO schemes, which rely on uplink training from the user terminals, and on uplink/downlink channel reciprocity. The BS employs virtual sector-based processing according to which, user-channel estimation and data transmission are performed in parallel over non-overlapping angular sectors. The uplink training schemes we consider are non-orthogonal, that is, we allow multiple users to transmit pilots on the same pilot dimension (thereby potentially interfering with one another). Elementary processing allows each sector to determine the subset of user channels that can be resolved on the sector (effectively pilot contamination free) and, thus, the subset of users that can be served by the sector. This allows resolving multiple users on the same pilot dimension at different sectors, thereby increasing the overall multiplexing gains of the system. Our analysis and simulations reveal that, by using appropriately designed directional training beams at the user terminals, the sector-based transmission schemes we present can yield substantial spatial multiplexing and ergodic user-rates improvements with respect to their orthogonal-training counterparts.

An overview of standardization efforts for enabling vehicular-to-everything services

Abstract: The Third Generation Partnership Project (3GPP) has been working on developing specifications on Machine to Machine Communications (M2M) and on the emerging Internet of Things (IoT) bringing light into the associated service and network requirements. This paper presents a special form of M2M/IoT communication, where at least one communication device is part of a vehicle that automatically communicates with other vehicles, pedestrians and Road Side Units (RSU). The initial efforts towards the so called Vehicular-to-Everything (V2X) specifications are based on group communications and on proximity service features, both originally developed for mission critical communications. Such standardization efforts are enhanced and also integrated in the new service model enabled by 5G systems for supporting verticals, with the automotive industry being one of the major players. This paper provides a comprehensive study elaborating the current standards for enabling V2X considering the co-existence of 3GPP, oneM2M and ETSI Multi-access Edge Computing (MEC), while analyzing potential open challenges.

Base station, user equipment, and radio communication system

Abstract: A base station determines the transmission powers of streams to be transmitted to UEs and precodes data signals and reference signals (DM-RSes) to be demodulated. The base station then transmits mixed data signals obtained by mixing the data signals that are addressed to the respective UEs and are not orthogonal to each other, and also transmits the DM-RSes. Regardless of whether the numbers of streams to be transmitted to the UEs are the same or not, the base station allocates, to the DM-RSes of the UEs, a resource element that is common to these UEs. Further, if the numbers of streams to be transmitted to the UEs are different, the base station allocates, as the common resource element, a resource element, which is suitable for a UE for which the number of streams is large, to the DM-RSes of the UEs, thereby equalizing the transmission powers by use of the common resource element.

Field Experimental Trials for 5G Mobile Communication System Using 70 GHz-Band

Abstract: This paper presents field experiments on the downlink throughput and SNR performance of a beam forming 5G millimeter wave radio access system with beam tracking in the following urban environments: a street canyon and a shopping mall. The majority of the area in the street canyon environment exhibits Line-Of-Sight (LOS) propagation while the shopping mall includes significant Non-LOS (NLOS) areas. The results show that the maximum throughput of over 2 Gbps is achieved in each of the respective environments. The Signal-to-Noise Ratio (SNR) and throughput performance versus distance from the AP is nearly identical for both environments in LOS conditions. Furthermore, if reflection paths exist, identical SNR and throughput performance is still achievable under these NLOS conditions. In addition, as an example use case of 5G enhanced mobile broadband, the world's first real time 8K video transmission trial using the system is also presented.

Computational Dosimetry of the Human Head Exposed to Near-Field Microwaves Using Measured Blood Flow

Abstract: Computational human thermal modeling studies have suffered from lack of reliable data regarding tissue blood flow. In this study, we report the measured results of blood flow on the surface of the head at multiple sites in human subjects (12 healthy young male subjects, 22-24 years), using a laser Doppler blood-flow method. We then incorporate these measured blood flow in a computational bioheat thermal model in anatomical human head models and investigate the effects of individual variations in blood flow on a microwave-induced temperature elevation in the frequency range from 1 to 12 GHz. The measurements show variations in blood flow at different sites and depths from the skin surface. However, computational bioheat modeling indicates that the typical variability of peak temperature elevation in the head due to individual and regional variations in the blood flow is less than ±15%. The presented data will aid in the development of more accurate and consistent human thermal models and strengthen the thermophysiological rationale of guidelines and standards for human radio-frequency near-field exposure.

Beamforming common channels in 5g new radio

Abstract: A method for wireless communication includes transmitting, with a base station (BS), multiple first signals using respectively different radio resources. The multiple first signals include a common signal component. The radio resource is identified by a radio resource ID. The method further includes receiving, with a user equipment (UE), out of the radio resources the multiple first signals from the BS, selecting, with the UE, a radio resource based on a reception quality of the multiple first signals, transmitting, from the UE to the BS, feedback information including the radio resource ID corresponding to the selected radio resource, and transmitting, from the BS to the UE, a second signal using the radio resource corresponding to the received radio resource ID.

Mobile communication system, base station, and user equipment

Abstract: In a mobile communication system including a base station provided with a plurality of antenna ports, and user equipment that executes radio communication with the base station, the base station transmits a beam stream including a first beam for transmitting data to the user equipment, and one or more second beams for transmitting a precoded reference signal in a direction toward a vicinity of the first beam; and upon receiving the beam stream, the user equipment selects, from the first beam and the second beam, and transmits, to the base station, one or more suitable beam indexes.

Two-Stage 3D Codebook Design and Beam Training for Millimeter-Wave Massive MIMO Systems

Abstract: Hybrid beamforming architecture that combines analog beamforming and digital beamforming has been widely accepted in the emerging millimeter-wave (mmWave) systems with large antenna arrays. However, the design of codebooks and beam training procedures at the analog stage is problematic in mmWave system. In this study, we propose a feasible two-stage 3D codebook design consisting of a primary codebook and an auxiliary codebook. The primary codebook generates a basic directional beam, and the number of phase shifts is quite limited in order to keep low hardware complexity. The small-size auxiliary codebook creates the finer beams that are centered on each primary beam. Furthermore, a beam search scheme designed for the two- stage codebook is proposed. We use a binary tree search method with antenna selection for the primary beam search, and a directed beam scan for the auxiliary beam search. Simulation results verify the performance advantages of our proposed codebook in beamforming gain and spectral efficiency for multi-user multiple-input multiple-output (MU-MIMO) systems. Moreover, training complexity comparisons indicate that our specially designed two-stage beam search scheme significantly outperforms other existing solutions.

Human behavior in a staircase during a total evacuation drill in a high-rise building

Abstract: Summary Many studies have been conducted on the evacuation behavior on the staircases of buildings, but very little data are available for a situation with many occupants in a crowded high-rise building. Therefore, this study investigated the evacuation behavior of a large number of evacuees on the staircase of a 25-story high-rise building. A total evacuation drill was conducted with 2088 evacuees, and the behavior of 1136 evacuees on the landings of the south staircase was recorded by a video recorder on the ceiling. The relationship between the density and speed of the evacuees on the landings was analyzed from the evacuation data for two situations: without and with merging in the stair flow. The evacuation stair flow in this drill had merging occupants entering from the floors, but no one entered from the lower floors during the latter period of the drill. Therefore, the flow during the latter period was treated as non-merging flow, for which it was observed that, when the staircase was fully crowded, the density on the landings in the moving situation was different from that in the stopped situation. Moreover, the density on the landings was different from that on the treads. Furthermore, in the merging flow, a merging ratio of approximately 50:50 occurred during the congested evacuation. Copyright © 2016 John Wiley & Sons, Ltd.

Coding for edge-facilitated wireless distributed computing with heterogeneous users

Abstract: We consider the edge-facilitated wireless distributed computing with three users, each communicating with the other two users via the help of an access point (AP) only. Motivated by the idea of MapReduce-based wireless coded distributed computing (CDC) proposed by Li et al. in [1] for homogeneous systems where each user's file storage size is identical, we attempt to extend MapReduce-based CDC to heterogeneous systems where each user has arbitrary file storage size. In this paper, we provide an achievable communication load region of the uplink-downlink transmission pair by appropriately designing file placement over the users and developing coding schemes at both the users and the AP. Moreover, we provide the converse for the communication load region, by decoupling the uplink and downlink transmissions. Finally, we provide a discussion on the shape of the load region for several examples and observations.

5G Experimental Trial of 28 GHz Band Super Wideband Transmission Using Beam Tracking in Super High Mobility Environment

Abstract: The fifth-generation (5G) mobile communication system has attracted much attention to provide various kinds of mobile services and applications for 2020 and later. 28 GHz band is one of the most potent bands for 5G since super wide bandwidth of almost 1 GHz will be available. In the high frequency band, beamforming is mandatory to compensate large path loss. Hence beam tracking mechanism is important to support user mobility, especially users travelling with high speed car or train. In order to clarify the feasibility of the 28 GHz band for mobile communication, we have conducted super high mobility experimental trial targeting up to 150 km/h velocity, by using 5G Massive MIMO (Multiple Input Multiple Output) prototype with beam tracking mechanism. This paper reports results from the super high mobility experiment held in Fuji Speedway, Japan.

5G Field Experimental Trial on Frequency Domain Multiplexing of Mixed Numerology

Abstract: This paper presents a field experimental trial on frequency-domain multiplexing of a mixture of multiple numerologies. The goal is to support diverse applications and services in the fifth generation mobile communications (5G) system. Frequency-domain multiplexing of mixed numerology has been discussed for 5G in order to flexibly support the variety of requirements introduced by future applications. However, frequency-domain multiplexing of mixed numerology causes inter sub-band interference. In this paper, we apply filtered-orthogonal frequency division multiplexing (f-OFDM), which is a new waveform, in order to reduce the inter sub-band interference. Through the field trial, we show that f-OFDM realizes mixed numerology while reducing the impact from inter sub-band interference compared to conventional cyclic prefix OFDM. The field trial results show that f-OFDM has no throughput degradation when using more than one guard subcarrier.