Special Session 7

5G physical layer design for high speed vehicles

  • Tuesday, 13 June 2017, 11:30-13:00, Room Radisson Blu Ainola 2
  • Session Chair: Jari Hulkkonen (Nokia, Finland)

 

High speed vehicles like trains introduce challenging scenario for communication: high number of active users having high data rate demand (typically xMBB service) are moving with high speed. Wireless communication is able to provide access to high moving vehicles, however, extreme velocities need to be take into account in the design. Specific problems for air interface design to support extreme velocities are: high Doppler shifts, Inter-Carrier Interference (ICI), difficulties in channel measurements needed for demodulation, PHY/MAC layer feedback, digital beam forming and hand-over measurements.

Multi-Gbps data rates require large bandwidths. Due to presence of line-of-sight e.g. in high speed train deployments, large bandwidths associated with mm-wave spectrum can be utilised efficiently. Outdoor macro cellular deployment on high carrier frequency requires high antenna gains.

In LTE 3GPP specifications the maximum speed of 350 km/h is used to define the maximum Doppler shift at Band 1 (i.e., around 2GHz). In 5G the maximum speed is updated to 500 km/h, and carrier frequency around 30 GHz is considered. These together means that the maximum Doppler shift increases by a factor of ~20 compared to LTE. This is one example about the problems that will require novel solutions in the 5G air interface.

As an example of high speed scenarios, 3GPP study on scenarios and requirements includes high speed train, highway and aircraft.