Two-way TCP performance issues and solutions in asymmetric LTE radio access

Protecting Download Traffic from Upload Traffic over Asymmetric Wireless Links

“…Figure 6 shows that throughput dynamics between downlink and uplink flow are strongly consistent with the testbed evaluation ( Figures 1 and 2). Downlink flow is severely reduced in the presence of uplink flow, with uplink and downlink flows 765 and 870 Kb/s during the period [20,40] As the second simulation study, we evaluated the NCR effectiveness for various uplink and downlink flows, aggregate downlink and uplink throughputs, and average end-toend delay using the following simulation scenarios: (i) the total simulation time was 60 s; (ii) uplink and downlink flow were active throughout the entire simulation; (iii) the number of downlink flows was varying from 1 to 3, and the number of uplink flows was changing from 1 to 5; (iv) 10 simulation runs were conducted for each simulation configuration. Table 1 compares indicative IEEE 802.11-based WLAN (normal WLAN) and NCR enabled WLAN cases.…”

“…Szilagyi and Vulkan proposed an evolved Node B (eNB) based solution called TcpAsym, by packing an additional entity [20]. TcpAsym controls each user equipment (UE) that might contain multiple TCP flows.…”

“…Some studies have addressed TCP upload or download throughput degradation in asymmetric links, including ADSL, cable, and satellite [14][15][16][17][18][19]. However, the proposed solutions generally impose additional overhead of maintaining separate packet queues [15][16][17][18][19][20][21][22][23][24], modifying TCP protocols or parameters [25,26], or tracking per-flow traffic statistics [18] on access points (i.e., base stations) or mobile stations. Thus, these solutions are either inappropriate or not sufficiently satisfactory to be applied to emerging wireless technologies.…”

Efficient LTE PDCP buffer management

“…The operation of the TCP packet pacing buffer management thus they are applicable to any TCP variant. By operating at the TCP level, the proposed mechanisms natively support encrypted connections (e.g., Transport Layer Security, TLS) and also handle bidirectional traffic efficiently as shown in the context of asymmetric links [14]. While the proposed mechanisms are operating based on different principles, they both fulfill the criteria defined in the previous section.…”

A fine-grained response time analysis technique in heterogeneous environments

“…Some related works [8,9,10,11,12] have focused on this problem and developed root cause analysis techniques that can determine the primary cause for the throughput limitation of a TCP flow from a passively captured packet trace. The novelty of our present work is that our technique is completely independent of both the applications and underlying PHY/MAC layer technologies.…”