## 1 Introduction  
New technologies such as automated intelligence, autonomous vehicles, the Internet of Things (IoT), high quality Internet Protocol (IP) telephony, broadcasting televisions (TVs), and high-speed data communication, among others, are becoming a reality. These technologies require faster, high capacity, quality of service (QoS) guaranteed, reliable, and continuous inter-connectivity among users and devices [1; 2]. To fulfill such demand, the 5 th generation (5G) mobile communication system is underway to provide an unparalleled connected mobile society by the year 2020 [3]. This new mobile paradigm will thus require significant technology advancement in both wireless and optical access networks. The centralized/cloud radio access network (C-RAN) architecture is an emerging enabling technology introduced into 5G networks, and is supposed to provide reduced capital expenditure (CAPEX) and operational expenditure (OPEX), high spectral efficiency, and low energy consumption [4]. Fifth generation (5G) C-RAN is proposed to support 5G mobile technology and enhance the RAN performance by centralizing the base-band unit (BBU) pool to hundreds or thousands of remote radio heads (RRHs), which transparently forwarded the received signal waveforms to the BBU via optical fronthaul links. In this way, 5G C-RAN highly simplifies the functionalities of the RRHs. Fronthaul is a paramount constituent in 5G C-RAN architecture, usually categorized as digitized radio-over-fiber (D-RoF) and analogue radio-over-fiber (A-RoF). The common public radio interface (CPRI) is the most commonly used D-RoF interface in the current C-RAN architecture designed for long-term evolution-advanced (LTE-A) networks [5]. Because CPRI transmits in phase and quadrature phase (IQ) samples converted into bit streams over fiber links using a spectrally inefficient on-off keying format, it requires very large bandwidth. For example, transporting 8 \(\times\) 8 multiple input-multiple output (MIMO) 3-sector 8 \(\times\) 100 MHz new radio (NR) waveforms requires a CPRI data rate of 147.456 Gb/s [6],which is impractical to implement in the 5G application. A-RoF is a fronthaul alternative used as a technique of aggregating massive NR waveforms on a single wavelength. As the bandwidth required in A-RoF for the fiber network depends directly on the wireless bandwidth, it mitigates the huge bandwidth requirement of CPRI. Moreover, it consumes a low amount of power and can be used in mm-wave frequency bands for 5G access networks. Therefore, A-RoF can be considered as a possible candidate for the future fronthaul network [6; 7].  
The key goal of this work is to analyze the A-RoF using digital signal processing (DSP)-based time division multiple access (TDMA) and frequency division multiple access (FDMA) channel aggregation techniques of multiple bandwidth uplink NR waveforms with respect to spectral efficiency and error vector magnitude (EVM) performance. To achieve this, we first simulated 5G NR uplink physical channels based on scalable subcarrier spacings (SCs) that corresponds to 50 MHz, 100 MHz, 200 MHz, and 400 MHz of bandwidth parts, each consisting of control physical uplink control channel (PUCCH) and data physical uplink shared channel (PUSCH), devoted for control and data transmission, respectively.  
The paper is organized as follows: Section 2 provides a brief overview of uplink channels specified in 3 rd Generation Partnership Project (3 GPP) technical specification. Section 3 describes the DSP setup of the two aggregation (FDMA and TDMA) techniques over intensity modulation and direct detection (IM-DD) optical fronthauling link. In Section 4, we present the simulation results obtained from setup of Section 2. Section 5 concludes the work presented by summarizing the outcome.