Satoshi Suyama

Joint fixed beamforming and eigenmode precoding for super high bit rate massive MIMO systems using higher frequency bands

In order to tackle rapidly increasing traffic, the 5th generation (5G) mobile communication system will introduce small cells using higher frequency bands with wider bandwidth to achieve super high bit rate transmission of several tens Gbps. Massive MIMO beamforming (BF) is one of promising technologies to compensate for larger path-loss in the higher frequency bands. Joint analog fixed BF and digital precoding has been proposed to reduce the cost of a Massive MIMO transceiver. However, the conventional scheme assumes the transmission of a few streams using well-known codebook-based precoding as the digital precoding, and both a selection method of the fixed BF weights and a digital precoder design, which are suitable for the super high bit rate transmission using multiple streams, have not been studied. This paper proposes a joint fixed BF and CSI-based precoding (called FBCP) scheme for the 5G Massive MIMO systems. FBCP first selects the analog fixed BF weights based on maximum total received power criterion, and then it calculates eigenmode (EM) precoding matrix exploiting CSI. This paper targets a 5G system achieving 20 Gbps in 20 GHz band as one example, and throughput performances of the proposed FBCP are evaluated by link level simulation and compared with those of the fixed BF and those of the EM precoding.

Super high bit rate radio access technologies for small cells using higher frequency bands

This paper overviews super high bit rate radio access technologies using higher frequency bands for future radio access for 5G. In small cells using higher frequency bands based on the Phantom Cell concept in which radio links for the control (C)-plane and user (U)-plane are separately connected to a macro cell and small cell, radio access technologies employing Massive Multiple-Input Multiple-Output (MIMO) are described that achieve super high bit rate transmission. Specifically, on the basis of 11 GHz band 8×16 MIMO and 24×24 MIMO preliminary investigations, we estimate the required transmission power for 20 Gbps transmission in 20 GHz band Massive MIMO. In addition, we show the basic performance of 20 GHz band Massive MIMO based on link level simulations.

Performance Evaluation of 44GHz Band Massive MIMO Based on Channel Measurement

5th generation mobile communication system using higher frequency band has gotten much attention, and massive-MIMO technologies have been expected to improve spectral efficiency dramatically. In order to reduce the complexity of massive-MIMO base station, the combination of analog beamforming (APAA: Active Phased Array Antenna) and digital MIMO signal processing for the multi-beam multiplexing is one of the promising approaches. In this paper, channel capacity evaluation with 44GHz-band APAA measurement results will be carried out and the possibility of large capacity transmission in LOS environment is shown. 44GHz band channel parameters - AoA, AoD, delay spread, etc. - will be shown and transmit performance results using cluster model are presented.

Indoor and outdoor experimental trials in 28-GHz band for 5G wireless communication systems

This paper presents the overview of the experimental trial for the 5th generation (5G) mobile communication systems based on the collaboration between Samsung Electronics and NTT DOCOMO. In order to tackle rapidly increasing traffic for 2020 and beyond, new radio access network for the 5G mobile communication systems will introduce the use of higher-frequency bands such as spectra higher than 10 GHz to achieve higher capacity and super high bit rate transmission of several tens of Gbps. The target of this experimental trial is to evaluate the effectiveness of using 28-GHz band with super-wide bandwidth of 800 MHz for 5G mobile communication systems. Firstly, the technical concept of this trial and the prototype design of the experimental system are presented. Massive multiple-input multiple-output (MIMO) technique is attracting attention to compensate for large path-loss in higher frequency bands. In this experimental trial, the beamforming (BF) based on Massive MIMO is introduced to the transmission using 28-GHz band. Some results of the indoor and outdoor experiments are also shown to evaluate the feasibility of using 28-GHz band with 800-MHz bandwidth.

Evaluation of 30 Gbps super high bit rate mobile communications using channel data in 11 GHz band 24×24 MIMO experiment

The performance of 30 Gbps super high bit rate mobile communications is evaluated by computer simulation using channel data collected in 11 GHz band 24×24 MIMO outdoor propagation experiments, and the feasibility of 11 GHz band 30 Gbps transmission is verified. To achieve the super high bit rate mobile communications, 10 Gbps transmission using 11 GHz band 8×16 MIMO has been verified in outdoor transmission experiments. In addition, channel measurement and analysis have been conducted in 11 GHz band 24×24 MIMO radio propagation experiments. Although 24×24 MIMO transmission is expected to achieve a bit rate exceeding 30 Gbps, transmission experiments have not yet been performed due to the hardware limitations. In this paper, computer simulations based on 24×24 MIMO-OFDM eigenmode transmission are conducted by utilizing channel data measured using an 11 GHz band 24×24 MIMO channel sounder. This paper shows that throughput exceeding 30 Gbps is achieved in 11 GHz band mobile environments, and clarifies the requirements for the average signal-to-noise ratio, channel conditions, and accuracy of channel state information to achieve 30 Gbps throughput over a real 11 GHz band 24×24 MIMO channel.

Experiment of 28 GHz Band 5G super wideband transmission using beamforming and beam tracking in high mobility environment

This paper presents some results of experimental trial in high mobility environment for the 5th generation (5G) mobile communication systems using 28 GHz band. In order to tackle rapidly increasing traffic for 2020 and beyond, new radio access network for the 5G mobile communication systems will introduce the use of higher-frequency bands such as spectra higher than 10 GHz to achieve higher capacity and super high bit rate transmission of several tens of Gbps. The target of this experimental trial is to evaluate the effectiveness of using 28 GHz band with super-wide bandwidth of 800 MHz for 5G mobile communication systems. To compensate large path-loss in higher frequency, the beamforming based on Massive multiple-input multiple-output (MIMO) is one of promising techniques and can be combined with spatial multiplexing of multiple data streams to achieve much higher capacity. In addition, to support the mobility of mobile station (MS), beam tracking technique is important. In this paper, we show some results of the outdoor experiment of Massive MIMO beamforming combined with spatial multiplexing in high mobility environment with MS speed of up to 60 km/h by using prototype system with base station (BS) having 96-element array antenna and MS having smartphone-shape antenna with 8 elements. We also show that maximum throughput of 3.77 Gbps can be achieved with MS speed of 60 km/h by using beamforming with 2-stream multiplexing and beam tracking.

Field experimental evaluation of beamtracking and latency performance for 5G mmWave radio access in outdoor mobile environment

In the fifth generation mobile communications system (5G), it is expected to use millimeter wave (mmW) radio access with very wide frequency bandwidths of more than 1 GHz. To achieve good coverage and availability, high gain antennas or arrays are essential in order to compensate for the higher propagation loss experienced at mmW frequencies relative to current cellular bands. This paper presents the beamtracking performance and throughput performance of a 5G mmW Proof-of-Concept (PoC) system in field experiments conducted at up to 20 km/h vehicular speeds in outdoor line-of-sight (LOS) conditions. In addition, this paper recomposes the frame structure for low latency and evaluates latency performance in the vehicular experiments.

Adaptive control CRE technique for eICIC in HetNet

This paper describes the performance of a state-of-the-art cell range expansion (CRE) technique: an adaptive control CRE for enhanced inter-cell interference coordination (eICIC) in Heterogeneous Network (HetNet). The features of the proposed adaptive control CRE technique are described through comparison with those of conventional methods. With eICIC in a HetNet, system-level computer simulation results such as average user throughput and 5-percentile user throughput are provided as parameters of almost blank subframes ratio for eICIC. This approach provides a remarkably effective solution for eICIC in a HetNet.

Flexible antenna deployment for 5G distributed Massive MIMO in low SHF bands

In order to tackle rapidly increasing traffic, distributed Massive MIMO (DM-MIMO) has been proposed for fifth-generation (5G) mobile communication systems. DM-MIMO coordinates lots of distributed transmission points (TPs) that are located in ultra-high density (UHD) and use various numbers of antenna elements for each TP. It can achieve drastic improvement of areal spectrum efficiency for 5G. It can also dynamically create user-centric virtual cells corresponding to user mobility. To design flexible antenna deployment of DM-MIMO that is applicable to various use cases in 5G, some key parameters such as the number of the distributed TPs, the number of antenna elements for each TP, and proper distance between TPs should be determined. This paper provides such discussion for 5G DM-MIMO with the flexible antenna deployment under fixed total transmission power and constant total number of antenna elements. Computer simulations show that DM-MIMO can achieve more than 2.5 times system throughput in comparison with a Massive MIMO system using 128 antenna elements.

Antenna deployment for 5G ultra high-density distributed antenna system at low SHF bands

In order to tackle rapidly increasing traffic, ultra high-density distributed antenna system (UHD-DAS) has been proposed for the fifth generation (5G) mobile communication systems. Unlike the 4G systems, UHD-DAS dynamically creates user-oriented virtual cells by cooperating lots of UHD distributed antennas, and thus it can drastically improve areal spectral efficiency. However, a design of antenna deployments for 5G higher capacity is important to determine key parameters such as a number of antenna elements per distributed transmission point (TP), proper distance between the transmission points, etc. This paper investigates an optimum design of the antenna deployments for 5G UHD-DAS as the appropriate number of TPs under fixed total transmission power and constant total number of antenna elements. Computer simulations show that UHD-DAS with 16 TPs can achieve higher area spectral efficiency more than 1.3 times in comparison with UHD-DAS with 4 TPs.