Date of Award
8-2025
Document Type
Dissertation
Publisher
Santa Clara : Santa Clara University, 2025
Degree Name
Master of Science (MS)
Departments
Computer Science and Engineering
First Advisor
Behnam Dezfouli
Abstract
As wireless networks, such as WiFi, have evolved from a convenient alternative to wired internet into the backbone of modern digital life, with approximately 19.5 billion devices deployed in 2023, the emergence of Virtual Reality (VR) and Augmented Reality (AR) applications has introduced unprecedented Quality of Service (QoS) demands that challenge existing wireless capabilities. While recent wireless standards have largely addressed throughput limitations, achieving consistent low-latency performance remains a significant challenge.
This thesis focuses on the implementation and performance evaluation of existing solutions to latency bottlenecks in wireless networks, and their impacts on User Datagram Protocol (UDP) and Transmission Control Protocol (TCP). Specifically, we consider two problems within the Reception (RX) buffer of devices: Head-of-Line (HoL) blocking and Out-of-Order (OOO) blocking. HoL blocking occurs when different application streams are multiplexed into the same reorder buffer, causing frame loss in one stream to block the delivery of successfully received frames from other streams. OOO blocking arises when the receive buffer enforces In-Order (IO) frame delivery despite upper layers being capable of handling OOO reception.
To investigate these issues, we implement and evaluate two existing solutions, using NS-3 simulation. First, we evaluate a stream de-multiplexing mechanism that separates traffic streams into different Traffic Identifiers (TIDs) by expanding available TIDs from 0–7 to 0–15 and evaluating Multi-TID Aggregated MAC Protocol Data Units (A-MPDUs), Block Acknowledgments (BAs), and Block Acknowledgment Requests (BARs). Second, we evaluate delay bounded RX buffers, enabling timeout-aware OOO frame delivery that balances latency and reliability requirements.
Our evaluation demonstrates significant improvements in blocking time and application-to-application delay for a dense environment. De-multiplexing two UDP traffic streams reduced the median blocking time by 22.0%, while applying a delay bound of 50 ms further reduced blocking time by 78.8%. This resulted in a median application-to-application delay reduction of 7.0% and 7.9% respectively. However, our results also reveal that delay bounds can be problematic when used with TCP, increasing the retransmission rate and the median Round Trip Time (RTT) by 1.33 KB/s and 3.7%, respectively.
Recommended Citation
Lee, Alvin, "Performance Evaluation of Delay-aware Packet Delivery in Wireless Devices" (2025). Computer Science and Engineering Master's Theses. 57.
https://scholarcommons.scu.edu/cseng_mstr/57
