# An Accurate Platform for Investigating TCP Performance in Wi-Fi Networks
## 2 Related Works  
Due to the popularity of TCP, there has been much interest in evaluating TCP CCAs in different network environments. In [4], the authors considered four common CCAs (i.e., CUBIC, New Reno, BBR, and Data Center TCP (DCTCP)) on two cloud computing platforms (i.e., Amazon's AWS and Google's GCP). They then conducted experiments and found an appropriate CCA for each application. In [5], [PERSON] et al. evaluated six loss-based CCAs in a physical 10 Gbps network emulating a wide area network. They found that the Binary Increase Congestion Control (BIC) and CUBIC CCAs are more suitable in high-speed environments. A significant amount of work has also been performed focusing on TCP CCA performance in wireless networks. The work in [6] evaluated Tahoe, Reno, selective acknowledgment (SACK), and Vegas in Long-Term Evolution (LTE) networks to find the best algorithm. In [7; 8], the authors discussed the design and evaluation of TCP in fifth-generation (5G) networks considering millimeter-wave wireless technology and 5G key performance indicator (KPI) requirements. In [9], the authors compared three CCAs in various scenarios on the ns-2 simulator and identified the most appropriate algorithm for each scenario. They found that Westwood+ markedly improves the performance of wireless links affected by losses. The present work focuses on TCP CCAs that are currently becoming more popular for use in Wi-Fi networks. In [10], the authors proposed a proximal policy optimization-based intelligent TCP congestion management method and showed that it reduces the delay compared to CUBIC on an emulator. However, the emulated network is an Ethernet network. There have been many investigations in the literature of TCP congestion control performance in Wi-Fi networks operating under different IEEE 802.11 standards. In [11], a Wi-Fi network with IEEE 802.11e was analyzed on a testbed with TCP traffic flows. In [12], a Wi-Fi network with IEEE 802.11n was considered for a constructed scenario of accessing the Internet. The authors experimented with six CCAs. After measuring the RTT and throughput for file transfers, they concluded that Yet Another High-speed TCP (YeAH) was the best CCA. In [13], a Wi-Fi network with IEEE 802.11n and IEEE 802.11 ac was built to evaluate and compare 13 TCP CCAs. The authors found that IEEE 802.11 ac outperformed IEEE 802.11n. In addition, BIC and CUBIC were better than the other CCAs in a single-hop scenario but comparable in a multihop one. The work in [14] also evaluated CUBIC and BBR in a real Wi-Fi network with 802.11n and 802.11 ac. The authors then proposed an improved variant of BBR, named BBR+, in which the pacing function of BBR is better controlled. The work in [15] evaluated the performance of TCP CCAs on an IEEE 802.11 ad link and revealed the excellent performance of BBR under multi-gigabit conditions. In [16; 17], there are efforts to evaluate TCP performance with IEEE 802.11 ax; however, they have just considered the default TCP CUBIC or TCP Reno. There has not been an extensive evaluation of TCP CCAs in the IEEE 802.11 ax network. In [18], they built a real 60 GHz mmWave network testbed and measured and analyzed the performance of TCP CCAs. They concluded that for Westwood, CUBIC, and NewReno, there were problems with the accuracy of channel bandwidth estimation, and for BBR, there were fairness problems. In [3], the authors evaluated 14 TCP CCAs in an emulated Wi-Fi network and compared RTT and throughput, showing that BBR performs best. Since there is no clear winner in all scenarios, the ability to evaluate CCAs to assess their capabilities in Wi-Fi networks with varying settings is necessary. Another TCP issue in Wi-Fi that attracts many researchers is bufferbloat. Accordingly, there are several solutions to the issue. In [19], the authors considered the so-called Active Queue Management (AQM), which schedules the packets at a queued link following a predetermined algorithm.