Broadband mobile networks have rapidly evolved over the last years. The unique environment they operate, however, sets new challenges for the Transmission Control Protocol (TCP). In this paper, we study the impact of Long Term Evolution (LTE) handover on TCP performance with different TCP congestion control algorithms and in a wide range of networks settings, including different handover types, random channel errors and support of error correction at lower layers. Our results suggest that the congestion control algorithms employed by TCP variants during the LTE X2 handover have different impacts on TCP performance. In particular CUBIC, Scalable TCP and BIC-TCP achieve high goodput and fast window convergence in available channel capacity after LTE X2 handover. In environments involving packet drops that are not corrected at lower layers and single errors with high probability, all TCP variants exhibit very low performance levels. Finally, in terms of fairness, our results identify fairness issues among TCP flows with different Bandwidth Delay Products (BDP), with CUBIC offering the best results.

宽带移动网络在过去几年中迅速发展。但是，它们所操作的独特环境为传输控制协议（TCP）提出了新的挑战。在本文中，我们研究了长期演进（LTE）切换对使用不同TCP拥塞控制算法以及在广泛的网络设置中对TCP性能的影响，包括不同的切换类型，随机信道错误以及对较低层的错误纠正的支持。我们的结果表明，LTE X2切换期间TCP变体使用的拥塞控制算法对TCP性能有不同的影响。特别是CUBIC，可扩展TCP和BIC-TCP在LTE X2切换后，在可用信道容量方面实现了高吞吐量和快速窗口收敛。在涉及无法在较低层进行纠正的数据包丢弃以及很有可能发生单个错误的环境中，所有TCP变体都表现出非常低的性能水平。最后，就公平性而言，我们的结果确定了具有不同带宽延迟产品（BDP）的TCP流之间的公平性问题，其中CUBIC提供了最佳结果。