Flexible Numerology in 5G NR: Interference Quantification and Proper Selection Depending on the Scenario

Abstract

The 3rd Generation Partnership Project (3GPP) adopted cyclic prefix OFDM (CP-OFDM) for both uplink and downlink communications (although DFT-s-OFDM is also allowed in the uplink) in 5G New Radio (NR) Release 15. However, due to the variety of proposed deployment options and scenarios, a single numerology will not be enough to fulfil all performance requirements. A scalable OFDM numerology was required to enable diverse services on a wide range of frequencies and deployments, and finding the right numerology for each scenario is of special relevance for the proper functioning of 5G NR. Using a simulator calibrated according to the parameters established for NR performance by the 3GPP, this paper presents the performance evaluation of NR for the main 5G scenarios and different CP-OFDM numerologies and device speeds. Results show that increasing subcarrier spacing boosts the strength of the system against intercarrier interference (ICI) caused my Doppler spread; however, to increase subcarrier spacing, the CP must be reduced proportionally, which makes intersymbol interference (ISI) and ICI caused by insufficient CP have a more predominant effect. Therefore, it is necessary to quantify the total interference of the system, in order to determine the proper numerology for each scenario, which will depend on all the factors mentioned above, and not only on the operation band, as suggested in the standardization process. All this allows concluding that the choice of the appropriate numerology for a particular system depends not only on the band of operation but also on the deployment scenario and the speed of the user equipment (UE). Likewise, it is concluded that it is even possible to use more than one numerology for the same scenario.

PAPR reduction in CP-OFDM (5G) using hybrid technique

“…In order to enable all of the operations that the 5G standard is designed to deliver, 5G NR must address three key issues: higher data speeds, transmissions with higher durability and lower latency, and a significant increase in the number of devices. The motivations leading to the three main use cases include [14]: enhanced mobile broadband (eMBB) which requires massive transmission speeds and huge bandwidths [14]. Second, ultra-reliable low-latency communications (uRLLC), which requires extremely high reliability and availability in addition to very low latency [15].…”

“…In addition, a single OFDM numerology defined by subcarrier spacing and cyclic prefix length is unable to achieve capacity limits throughout the required frequency spectrum and entire recommended placement choices and scenarios. Therefore, the OFDM numerology must be customised for each service demand, operating frequency, and deployment environment [14,18]. The cyclic prefix (CP) orthogonal frequency-division multiplexing (OFDM) was chosen for its various advantages, including good support for multiple-input multipleoutput (MIMO) and granularity in frequency-domain resource allocation [17].…”

Optical Transport Architecture for the Fronthaul Segment in a 5G NR Network based on Polarization and Wavelength Multiplexing

“…Previous works have shown the flexibility that multiple numerologies provide to 5G networks, compared to LTE, due to the use of numerologies [6]. Also, [7] presents the performance of NR for different scenarios of the mobile network based on the numerologies' parameters established by 3GPP. In [8], the segmentation analysis for Radio Access Networks (RAN) in the physical layer is performed to relate the multiple numerologies with the network slicing.…”

Complex-Valued Phase Transmittance RBF Neural Networks for Massive MIMO-OFDM Receivers

“…Multicarrier modulation schemes, such as OFDM, have been widely employed in digital communications systems due to their low susceptibility to intersymbol interference (ISI) [6][7][8][9]. OFDM divides the channel bandwidth into K orthogonal subcarriers [10].…”