5G Radio Access Technology

ASTRI is actively contributing to national 5G standardisation initiatives such as China Mobile FuTURE Forum, 5GPPP, and NGMN. In particular, ASTRI’s research focus in 5G radio access technologies covers the following 6 areas:

Massive MIMO

ASTRI’s massive MIMO research primarily addresses the following issues:

• Reference signal design and channel estimation algorithms for centralised massive MIMO systems.
• Interference mitigation in distributed massive MIMO systems.
• User scheduling and beamforming methods with statistical/instantaneous channel knowledge.

 Centralised Radio Access Network (C-RAN)

C-RAN is a centralised, cloud based new cellular network architecture that can be adopted by telecom operators to improve their quality of service with reduced capital expenditure (CAPEX), operating expenditure (OPEX), and energy consumption. ASTRI is developing flexible and high system performance C-RAN solution to fulfil the demanding industrial requirements.

ASTRI proposed C-RAN architecture is based on the standard FAPI PS-PHY interface, which can easily integrate with commercial protocol stack (PS) software. ASTRI modular PHY processing architecture provides the flexibility to adopt different partitioning requirements for the server and remote unit depending on the deployment scenarios. For more information, please click C-RAN

Ultra-Dense Network (UDN)

In UDN, low-powered cells are densely deployed for enhancing system capacity and coverage while reducing latency and energy consumption. ASTRI’s UDN research focuses are:

• Network architecture for control and user plane splitting.
• User mobility management and cellular load balancing algorithms.
• Interference mitigation methodologies, including inter-cell synchronisation and coordination, cell discovery, and receiver algorithms for interference cancellation/suppression.

Device-to-device Communication (D2D)

D2D is a technology that allows user equipment to directly communicate with each other with or without cellular coverage. Since D2D may operate without cellular coverage, it is suitable for low latency and robust communication between users within proximity of each other. ASTRI’s D2D research focuses to address the following issues:

• Transceiver algorithms for user discovery and direct communication.
• Mesh network algorithms.

Emerging Systems for Efficient/Dynamic Spectrum Utilisation

ASTRI is conducting research on the following two areas:

• TV white space (TVWS): TVWS is an unused television broadcast spectrum resource that can be utilised through spectrum sharing. ASTRI is currently investigating the technical feasibility of adopting TVWS technology in Hong Kong, and has developed LTE-based TVWS infrastructure equipment.

• Licensed-assisted access (LAA): LAA is the operation to aggregate a primary cell by using licensed spectrum to deliver critical information and guaranteed Quality of Service, and a co-located secondary cell by unlicensed spectrum, to opportunistically boost data rate. ASTRI’s LAA research seeks to address the following issues:
  • Inter-radio access technology interference mitigation.
  • Sensing, synchronisation, and measurement algorithms for dynamic spectrum access.