TCP performance issues in LTE networks

We describe issues on the TCP performance in LTE networks. TCP throughput is determined by various factors such as TCP window size, loss probability and RTT. We present measurement results of TCP throughput in a real LTE testbed with various factors and TCP auto-tuning enabled. As expected, the test results show that the AM bearer outperforms the UM bearer due to less loss probability in the former. However, test results show that delay spikes incurred by the RLC ARQ increase TCP RTT and degrade TCP performance. We propose some enhancements for improving TCP throughput in LTE networks.