# Congestion Analysis of Transport Layer in a Multicell 5G DL Communication System
## 1 Introduction  
Wireless communication networks are making rapid progress towards their full implementation. It is already known that the complexity of fifth-generation (5G) systems will significantly increase, particularly in terms of the network architecture and wireless connection. These 5G systems bring new standards, increased energy and spectrum efficiency, extraordinarily high data rates, and new transmission techniques [1], while supporting a wide range of new applications and platforms, including the Internet of Things (IoT) [2], virtual reality (VR), augmented reality (AR) [3], autonomous vehicles, machine-to-machine (M2M) communications, tactile Internet (TI), software-defined networking, and multi-access edge computing. Optimizing the flow of traffic throughout the network and ensuring that several networks can coexist without interfering with one another is a crucial component in actual and future wireless communication networks [4, 5]. The 5G technology has the potential to produce a transformative effect on multiple aspects of society by enhancing efficiency, productivity, and overall performance. The established goals of 5G are ambitious: capacity increases of up to a 1000 times, data rates of up to 20 Gbps, network slicing, and much higher stability [6]. The fifth generation is a substantial step forward in the capabilities of mobile networks. Up until this point, consumers' mobile phones, tablets, and laptop computers have all been able to connect to the Internet thanks to the availability of mobile networks. When it comes to data rates, capacity, spectrum efficiency, and availability, 5G goes above andbeyond what was previously possible with long-term evolution (LTE) and LTE Advanced. The implementation of 5G wireless communication demands the development of new use cases, new technologies, and new network architectures [7; 8; 9]. Through the development of the standard known as International Mobile Telecommunications (IMT), the International Telecommunication Union (ITU) has been actively participating in the process of worldwide standardization of mobile communication systems [10]. \"IMT Vision--Framework and overall objectives of the future development of IMT for 2020 and beyond\" was adopted as Recommendation ITU-R M.2083 [11] by the ITU in September of 2015. One of the most significant aspects of the Recommendation is the identification of three use-cases scenarios in IMT-2020 for 5G, see Figure 1, which are as follows:  
* Enhanced mobile broadband (eMBB): Supporting eMBB usage scenarios, which demonstrate improved performance and a smoother user experience when compared to pre-existing mobile broadband applications, is a priority. Enhanced mobile broadband service presents high data speeds, high traffic capacity, and seamless mobility for hotspots and wide-area coverage [12]. The initial implementation of 5G networks will support consumer market needs, including rising smartphone subscriptions and mobile data growth. The 5G applications classified in this scenario are virtual reality, mobile cloud computing, fixed wireless, and UHD video. The authors of [13] underline that eMBB traffic uses the time slot as its transmission period to meet the requirements for both a high data rate and a high throughput. Essentially, eMBB service extends LTE Advanced broadband by allowing higher data rates and faster coding over large transmission blocks for a long duration. Thus, the eMBB system is targeted for high data rates and moderate reliability with a packet error rate (PER) of \(10^{-3}\)[14]. The minimal peak data rates for the eMBB usage scenario are 20 Gbps for downlink (DL), 10 Gbps for uplink (UL), and 4 ms for user plane latency.