Centralized-RAN (C-RAN) is an architectural trend that uses resource sharing and a set of interference mitigation techniques to reduce capital and operational expenditures for mobile network operators (MNOs). One of the technical enablers of a C-RAN solution is single frequency network (SFN) that curbs the interference and allows MNOs to transmit over single frequency across coordinated cells. One of the main advantages of SFN is that it reduces the number of handovers between neighboring cells while improving the overall system performance. In contrast to previous approaches that demonstrate some of the most prominent C-RAN features, in this paper, we first investigate two different SFN deployment scenarios' characteristics, benefits, and limitations. Second, we perform a simulation analysis of non-SFN and SFN without joint scheduling to observe signal to interference ratio heatmap distribution of the experimental test-site using similar system configurations. Finally, we perform an experimental analysis of joint scheduling in SFN based on coordinated inter baseband units scenario using C-RAN in a realistic environment. The experimental results are tested on a real operating site of a major MNO's infrastructure in Turkey. Through experimental results, we show overall performance gains of SFN feature in terms of different key performance indicators that are obtained from coordinating remote radio units in an SFN cell. Finally, we discuss about the main takeaways, lessons learned, and challenges of the considered SFN implementation.

According to International Mobile Telecommunication's requirements for 2020, next generation cellular networks such as 5G need to meet certain Key Performance Indicator (KPI) targets. Centralized-Radio Access Networks (C-RAN) is a novel technique that can address growing capacity needs of Mobile Network Operators (MNOs) due to ever increasing demands of their users. In order to meet stringent requirements of next generation cellular networks, C-RAN enabled techniques have attracted a lot attention due to their efficient spectrum (band, bandwidth) utilization (e.g. via carrier aggregation (CA)), spectrum efficiency (e.g. via Inter-Cell Interference Coordination and cancellation using Coordinated MultiPoint (CoMP) Transmission/Reception). In this paper, we investigate three different CA scenarios along with their benefits and limitations from the perspective of MNO. Additionally, we analyze inter-Baseband Unit (BBU) uplink (UL) CoMP feature as a real-world experimental C-RAN implementation in an operational suburban site of Istanbul in Turkey. Quantitative CA performance measurements demonstrate performance comparison of the considered three CA scenarios, and depending on each MNO's strategy, different CA gains are observed (e.g. LTE 1800 Mhz

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