Potential Design for Modulation and Coding Scheme in mmWave Multicarrier HetNets

Millimeter wave (mmWave) technology is expected to achieve higher data rates in fifth-generation (5G) mobile systems. Higher-order modulation such as the 256-quadrature amplitude modulation is also a key technology for increasing data rates. In multicarrier heterogeneous networks (HetNets) with picocells that uses mmWave technology, we propose a potential design for a modulation and coding scheme (MCS) in which lower-order modulation is prioritized in the picocells although a macrocell that uses 2 GHz is maintained at higher-order modulation in the MCS. The cell range expansion (CRE) technique, which virtually expands the picocell coverage, is very important for HetNets. Here, we investigate the overall user throughput of the proposed MCS design as a function of cell selection offset (CSO) in the CRE. The average and 5-percentile user throughputs of the proposed MCS design are described for multicarrier HetNet combined with macroï" evolved node B (eNB) using a carrier frequency of 2 GHz and low-power pico-eNB with a wider signal bandwidth using 28 GHz. We confirm that a CSO of 40 dB can provide the best performance, and the proposed MCS design can improve the average and 5-percentile user throughputs by 3% and 11% compared with the conventional, respectively, under the assumption that the signal bandwidth of a three-sector pico-eNB is 10 times wider than that of the typical macro-eNB. This work will provide a remarkably effective solution for multicarrier HetNets using the mmWave technology.