Enhanced Transport Block Processing for 5G NR PUSCH Coverage Enhancement

Abstract

In 5G-New Radio (5G-NR), the available transmission power at the user is limited, and thus, the uplink transmissions define the coverage of 5G-NR systems. In this paper, we propose various solutions to enhance the uplink coverage of 5G-NR. Each payload of the user in 5G-NR is appended with a cyclic redundancy check (CRC) before channel encoding and transmission. We identify that the overhead with the CRC attached payload is as high as 40% in the cell-edge transmissions. To address this issue, we propose a mechanism to transmit the data over multiple slots with a single CRC attached to the payload. This method significantly reduces the CRC overhead and improves the cell-coverage. Through link-level evaluations, we show that this proposed method achieves 450 meters improvement in the cell-coverage for the VoIP scenario. Further, we identify the under-utilization of resources in the special slots in Time-Division-Duplex (TDD) systems. To reduce the reference signal overhead in the special slot transmissions, we have proposed allocating the resources by jointly considering the available symbols in special and uplink slots. Through link-level evaluations, we show that this proposed scheme achieves an improvement of close to 2 dB in the link performance and 400 meters improvement in the cell coverage of the eMBB scenario.