Mobile Transmission Research Department

• Introduction
• Areas for Research & Development

• measurement and modeling of the mmWave propagation characteristics
  Different from the frequency band(800MHz ~ 6GHz) used for cellular mobile telecommunications, mmWave frequency band suffers from the fast radio propagation attenuation and propagates straightly. The conventional channel models are not suitable for the mmWave frequency band, which indicates that a novel model is necessary for system design and network construction using mmWave. For channel modeling, the measurement data can be used to model the radio characteristics. Alternatively, the Ray Tracing method based on the geographic features can also be used to generate the channel model. With the parameters related to the channel characteristics and system standards obtained through the cooperation from the Wireless Application Research Department, the standardization feasibility for the “Giga Korea-5G” and the “High-speed mobile wireless backhaul” is expanded and well planned in the Wireless Transmission Reseach Department. Furthermore, in order to actively standardize the channel modeling released by the 3GPP 5G workshop which was held in September 2015, we are trying our best to maximize the possibility of making good use of the mmWave for mobile telecommunications.
  
  <Channel sounder, radio wave measurement and the analysis of the mmWave channel characteristics>
  
  <Analysis of the mmWave channel characteristics using geographic features based radio tracking>
• Development of mmWave based 5G mobile telecommunication systems
  Leaded by the Giga Korea-Network Consortium in the Wireless Transmission Research Department, the mmWave based 5G mobile telecommunication systems are being developed. In order to implement the new mobile telecommunication systems employing mmWave, the early developed key elementary techniques have been verified through the system interoperability test. In particular, the domestic technological prowess will be improved if the developed key elementary techniques are adopted by the international standardization organizations and included in the standards.
  For this purpose, as a part of the project of “development of the mmWave based 5G mobile telecommunication systems”, we are working on the “deveploment of the mmWave(10~40GHz) based broadband mobile telecommunication systems supporting Giga-bit mobile services” to achieve the targets of : 1) developing standards and its international standardization, 2) developing the base station supporting maximum data rate of 100 Gbps and 3) developing the TE prototype supporting average 1 Gbps and maximum 1.5 Gbps services.
  
  In the 3rd year of the project of “development of mmWave based 5G mobile telecommunication systems”, the indoor/outdoor demonstration of the developed base station and TE are realized, which are able to achieve up to 20Gbps data rate by employing the TDD mode, 16 beams per cell (48 per Node B), 8 FA(frequency allocation) and 1GHz bandwidth at the carrier frequency of 28 GHz. In next year, the base station will be capable of providing up to 100 Gbps data rate and the TE will be updated in order to achieve higher maximum transmission rate. The updated systems are planned to be demonstrated and provide services during the 2018 Pyeongchang Olympic Games.
  
  One of the most important key techniques in the mmWave based 5G mobile telecommunication systems is the beam switching technique which can efficiently support the mobility management among beams of the same base station. In order to guarantee the QoS of voice call to a certain level in the mmWave environment, the low latency beam switching must be available to minimize the interference among beams, i.e., maximization of the signal-to-interference ratio. For the purpose of realizing the low latency beam switching, not only the key techniques related to PHY layer but also the MAC/RRC functions should be jointly designed. The cross-layer development of the hard-mode and soft-mode beam switching techniques are shown in the following figure.
  
  Currently, the PHY layer standard V1.1 and the higher layer standard V1.0 have been developed for the mmWave based 5G mobile telecommunication systems, and the test of the integrated prototype based on the standards is on-going. The integrated prototype is composed of the core network emulator, base station supporting 20Gbps data rate, and the TE supporting 1Gbps(maximum 1.5Gbps) data rate. The base station is working with the multiple number of beams and 1GHz bandwidth at the carrier frequency of 28GHz. Meanwhile, in order to miniaturize the TE working at the same carrier frequency (support 1GHz bandwidth), the RFIC is in development and the test of the TE chips will be performed in January 2016.
  
  Fast beam switching elementary technique employing multiple beams with multiple TEs has been tested and demonstrated in indoor environment. The UL/DL data transmission with full protocol stack and the developed beam switching technique will be demonstrated in December of 2015, and the mobility management and handover of the TE in outdoor environment will be demonstrated with the base station supporting 20 Gbps data rate in April 2016.
  
  <Final targets of the mmWave based 5G mobile telecommunication systems>
  
  <Images of the prototype for the mmWave based 5G mobile telecommunication systems>
  
  <Concept of the beam switching key techniques for the mmWave based 5G mobile telecommunication systems>
  
  <Main components of the mmWave based 5G mobile telecommunication systems>
  
  <Beam switching/handover test bed for the mmWave based 5G mobile telecommunication systems>
• Standardization of radio access technologies for 5G mobile telecommunication systems
  The project of “Development of 5G Mobile Communication Technologies for Hyper-connected smart services” has been going since 2014 and made enabling technologies of 5G radio access in sub-6GHz frequency bands. In order to provide three 5G service scenarios of enhanced Mobile Broadband(eMBB), ultra-reliability and low latency (Ultra-high reliable and low-latency), and massive Internet of Things (massive IoT), we has developed key technologies for 5G radio access and tried to verify their validities using proof of concept (PoC) or trial testbed systems.
  ITU-R WP5D made the process and timeline of implementing 5G mobile communication recommendations and presented the eight KPIs to be achieved by them. 3GPP begins study on new radio access technologies for a 5G radio access and is going to finish developing the phase I and II specifications of the 5G radio access in Rel-15 and Rel-16, respectively. Commercial 5G mobile communication systems is going to be deployed after 2020.
  
  The mobile transmission research department develops key technologies of 5G wireless access for achieving 8 KPIs ITU-R was presented. The key technologies are classified into the macro cell technologies in below-6GHz frequency bands and the small cell technologies in above-6GHz frequency bands including mmWave frequency bands. The GK-5G and QK-5G projects focus on developing key technologies in mmWave and below-6GHz frequency bands, respectively. In addition, we are going to submit contributions for the 3GPP standardization activities.
  The 5G radio access technology provides all the 5G service scenarios and allows for the development of radio access technology to provide flexibility for each service scenario. It includes key technologies in the fields of supporting unified frame structure, service-specific wireless transmission and control technology, service-specific radio access technology, and multi-frequency band and multi-RAT technologies.
  
  <Timeline of developing 5G radio access recommendations>
• Study on Mobile Xhaul Network (MXN)
  M-bile Xhaul Netw-rk is a new m-bile c-mmunicati-n techn-l-gy that enables m-bile netw-rk -perat-r t- flexibly expl-it radi- res-urce -f 5G m-bile c-mmunicati-n netw-rk depl-yed with vari-us small cells based -n SDN/NFV. F-r the MXN, -ur research divisi-n is studying f-ll-wing technical issues.
  
  - 5G RAN architecture with Xhaul (Fr-nthaul + Backhaul)
  - Radi- res-urce management f-r Xhaul
  - Beam f-rmati-n and adjustment f-r Xhaul link and Xhaul Relay
  - Integrated transmissi-n techn-l-gy with A6G(Ab-ve 6GHz)/B6G(Bel-w 6GHz) f-r Xhaul capacity enhancement
  
  <The concept of backhaul and fronthaul>
• Study on radio transmission technology for Massive Internet of Things(IoT)
  Radi- transmissi-n techn-l-gy f-r massive I-T is a fundamental techn-l-gy t- acc-mm-date -ver -ne milli-n -f c-mmunicati-n devices per unit area such as 1Km2. F-r the radi- transmissi-n techn-l-gy f-r massive I-T, -ur research divisi-n is studying f-ll-wing technical issues.
  
  - Wavef-rm f-r massive I-T
  - Multiple access scheme f-r massive I-T
  - Radi- transmissi-n techn-l-gy f-r massive I-T with LTE enhancement
  
  <New waveform for massive IoT>
• UE-centric virtual cell formation technology based on ultra-dense network
  Multiple transmission/reception points are densely deployed to increase the areal traffic capacity and spectral efficiency. The cell-centric deployments have fixed the cell area and suffer from a cell edge in which other cell interference limits the user data rates severely. On the other hand, UE-centric virtual cell deployments enable users to select the optimal transmission/reception points or virtual cells free of a cell edge. Multiple-point, multiple-layer transmission/reception technologies provide users with multiple data streams and increased data rates. Inter-point and inter-user interference mitigation and cancellation technologies are also critical.
  
  <UE centric virtual cell formation based on ultra-dense network>