Design of DMRS schemes for 5G vehicular communications

Proceeding of: 2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring), 25-28 April 2021, Helsinki, Finland (Virtual edition)The arrival of the fifth generation (5G) of mobile communications is boosting vehicular communications, an important use case addressed in the recent years. LTE introduced a sidelink radio interface through which user equipment would communicate directly with no necessary dependence on the network, named PC5. 5G has defined its own sidelink interface, NR-Sidelink, envisaged to improve PC5. This paper analyses the use of Demodulation Reference Signals (DMRS) to estimate the channel in sidelink communications. Improving several mappings proposed by the standards, the main contribution proposed in this paper is a new DMRS mapping with a better performance. The proposed Unequal Pilot Spacing (UPS) mapping can enhance the standard with a satisfactory trade-off between performance and overhead.This work has been supported by the Spanish National Project TERESA-ADA (TEC2017-90093-C3-2-R) (MINECO/AEI/FEDER, UE)

Data rate maximization based power allocation for OFDM System in a high-speed train environment

© 2015 IEEE. The channels in a high-speed train (HST) environment are very quickly time-varying within an OFDM symbol so it is preferable to have their estimation and symbol detection to be simultaneously implemented. Time-varying characteristics of the channels also causes unavoidable inter-carrier interferences, which make both channel estimation and symbol detection doubly difficult. Considered in this paper is a power allocation between pilot symbols and data to maximize the sum symbol rate. The average channel complex gains are estimated and are used to obtain the basis expansion model (BEM) of the HST, upon which the data detection is based. The simulation results confirm the viability of our proposed algorithm