Transmission Performance of an OFDM-Based Higher-Order Modulation Scheme in Multipath Fading Channels

Abstract

Fifth-generation (5G) mobile systems are a necessary step toward successfully achieving further increases in data rates. As the use of higher-order quadrature amplitude modulation (QAM) is expected to increase data rates within a limited bandwidth, we propose a method for orthogonal frequency division multiplexing (OFDM)-based 1024-and 4096-QAM transmission with soft-decision Viterbi decoding for use in 5G mobile systems. Through evaluation of the transmission performance of the proposed method over multipath fading channels using link-level simulations, we determine the bit error rate (BER) performance of OFDM-based 1024-and 4096-QAM as a function of coding rate under two multipath fading channel models: extended pedestrian A (EPA) and extended vehicular A (EVA). We also demonstrate the influence of phase error on OFDM-based 1024-and 4096-QAM and clarify the relationship between phase error and the signal-to-noise ratio (SNR) penalty required to achieve a BER of 1 × 10 −2 . This work provides an effective solution for introducing higher-order modulation schemes in 5G and beyond.small-cells [8,9], which can improve both system capacity and link budget because each eNB in a small-cell is directly connected to a core network. As another small-cell strategy, the concept of a phantom cell, has been proposed to provide efficient management of radio resources and mobility operation, where small-cells are overlaid on a macro-cell [10,11]. This approach splits the control and user-data planes; that is, the macro-eNB manages all UE within the overlaid cells, although UE can connect to a neighboring low-power eNB in the small-cell.Heterogeneous networks (HetNets) are another solution of denser infrastructures in which smallor pico-cells with low-power eNBs are installed within the coverage area of a macro-cell [12][13][14][15][16]. The objective of HetNet is to allow the UE to access pico-cells that overlap within a geographical coverage area even when the UE is within the coverage of a donor macro-cell. In other words, when the traffic in the donor macro-cell increases, its UE can access the pico-cells automatically. Through this mechanism, HetNet can increase system capacity, particularly when there is the heavy traffic in the macro-cell.Relay systems are an alternative approach to denser infrastructures that are primarily useful in improving cell edge performance in macro-cells [17][18][19]. In this scheme, a relay node (RN) installed at a macro-cell edge where the received signal power from the serving eNB is low can transmit a strengthened signal to the UE. Thus, the RN can physically reduce the distance between eNB and UE. Three-dimensional (3D) beamforming is another key technology for achieving 5G in which antenna beams can be individually tailored to each UE in the elevation domain through the use of a massive multiple-input and multiple-output (MIMO) antenna architectures. The use of 3D beamforming by MIMO antennas enables directs signal transmission toward a target UE, potentially increasing the received signal-...

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“…These increased requirements cannot be fully met with Quadrature Amplitude Modulation (QAM) formats such as 16/64 QAM which have widely been used in WiFi and 4G Long Term Evolution (LTE) applications. A notable feature of 5G will be dense infrastructure networks in which the distance between a base station (BS) and user equipment (UE) is reduced and the link budget is improved, allowing higher order modulation based channels to operate [6]. The 3 rd Generation Partnership Project (3GPP) release 12 started supporting 256 QAM for LTE downlink, and now with release 15, 1024 QAM support has been added.…”

A W-Band Communication and Sensing Convergence System Enabled by Single OFDM Waveform

“…We performed frequency domain equalization (zeroforcing) by using the transmitted pilot subcarriers for the channel estimation. As a result, a BER of 0.01 is recorded by comparing the transmitted and received data bits, when the average received SNR is around 15 dB, which is below the soft-decision forward error correction (SD-FEC) threshold of 1.5 × 10 −2 [39]. As a comparison, a BER of 3.6 × 10 −4 is obtained in the simulation due to the absence of the background reflections.…”

Personal Picocell Scheme Using Adaptive Control CRE in Heterogeneous Mobile Networks

“…In this paper, we focus on the performance evaluation of downlink user throughput. As the use of higher-order QAM is expected to increase data rates within a limited bandwidth, the implementation of 1024-QAM and 4096-QAM has been discussed [26][27][28] for 5G and beyond. However, in the simulations, we use 15 types of MCS indexes up to 256-QAM in the downlink as listed in Table 2, because the application conditions for these post 256-QAM are currently very limited.…”