Hi, I'm Sizhe Wang
I am a PhD student of Computer Engineering at Northeastern University, supervised by Prof. Dimitrios Koutsonikolas in the NUWiNS lab. My research interests span across experimental wireless network studies (5G & LEO satellite networks), mobile and spatial computing, and internet content routing analysis.
Currently, I'm working on concurrent measurement with 5G and LEO satellite networks under mobility across different regions and terrains in US, analyzing the characteristics of digital divide as well as exploring the potential of synergy of 5G and LEO satellite networks.
I'm passionate about bridging the gap between theoretical research and practical applications, always striving to develop solutions that can make a real impact in the field of mobile networked systems.
Research
- 5G Network Protocols
- LEO Satellite Networks
- Content Routing
- Open RAN
- Multipath Networking
- Mobile Computing
- Spatial Video Streaming
- XR Technologies
Milestones
2025-08-15
2025-08-15
Completed internship at AT&T Services, Inc.
2025-06-02
Started as Research Intern at AT&T Services, Inc.
2025-05-19
PhD Qualifying Examination passed
2025-01-24
2024-09-08
2024-01-07
Started as Ph.D. Student in NUWiNS Lab at Northeastern University
2022-09-07
Started as Master Student at Northeastern University
Publications
Tags:
Exploring the 5G Digital Divide in the Non-Contiguous US: LEO Satellites to the Rescue? Featured
2025
conference
5G cellular networks and Low-Earth-Orbit (LEO) satellite networks, such as Starlink, promise enhanced performance and coverage capabilities. While a large number of research works have evaluated these technologies in the mainland US, their performance in non-contiguous US regions remains under-explored, despite their unique challenges and significant visitor demands. Through extensive drive tests covering over 4200+ km across Alaska, Maui (Hawaii), and the mainland US (as a baseline), while simultaneously measuring the performance of the three major US mobile operators and Starlink, this work presents the first detailed evaluation of cellular and Starlink network coverage and performance in the non-contiguous US regions. Our study shows a persistent digital divide between mainland and non-contiguous US for cellular networks in terms of coverage and performance, highlighting the challenges of cellular deployments in non-contiguous US regions. Starlink provides substantially higher performance than cellular networks most of the time, but area-specific challenges, including unique terrains in Hawaii and sparse satellite deployment in Alaska, significantly degrade performance compared to the mainland US. Additionally, we explore the spatiotemporal diversity between cellular and Starlink performance and study the potential of multipath transport to bridge the connectivity gap in non-contiguous US regions.
A First Large-Scale Study of Operational 5G Standalone Networks
2025
conference
As 5G technology has reached its midlife, mobile operators are increasingly rolling out 5G Standalone (SA), which is pivotal in unlocking the full potential of 5G networks. Prior research has mainly focused on 5G Non-Standalone (NSA) performance, while comprehensive evaluations of operational 5G SA deployments remain scarce. Through two cross-country US driving trips (3200+ km) in 2023 and 2024, we conduct, to the best of our knowledge, the first large-scale study of T-Mobile’s 5G Standalone (SA) deployment in the US, analyzing its evolution while comparing it head-to-head with 5G NSA. Our study shows a shift in the operator’s 5G deployment priorities from 2023 to 2024 in favor of 5G SA compared to 5G NSA, with 5G SA deployments extending across diverse geographical areas. Advanced features, such as higher carrier aggregation with diverse band combinations and new frequency bands with different duplexing capabilities, allow SA to achieve better performance compared to NSA, whose peak performance has plateaued, reflecting limited upgrades as the operator transitions to SA infrastructure. Additionally, we examine the handover duration and uplink power control in SA and NSA networks, offering deeper insights into the operational dynamics of the two modes.
Replication: "Performance of Cellular Networks on the Wheels"
2025
conference
In 2022, 3 years after the initial 5G rollout, through a cross-country US driving trip (from Los Angeles to Boston), the authors of [28] conducted an in-depth measurement study of user-perceived experience (network coverage, performance, and QoE of a set of major 5G "killer" apps) over all three major US carriers. The study revealed disappointingly low 5G coverage and suboptimal network performance – falling short of the expectations needed to support the new generation of 5G "killer apps. Now, five years into the 5G era, widely considered its midlife, 5G networks are expected to deliver stable and mature performance. In this work, we replicate the 2022 study along the same coast-to-coast route, evaluating the current state of cellular coverage and network and application performance across all three major US operators. While we observe a substantial increase in 5G coverage and a corresponding boost in network performance, two out of three operators still exhibit less than 50% 5G coverage along the driving route even five years after the initial 5G rollout. We expand the scope of the previous work by analyzing key lower-layer KPIs that directly influence the network performance. Finally, we introduce a head-to-head comparison with Starlink’s LEO satellite network to assess whether emerging non-terrestrial networks (NTNs) can complement the terrestrial cellular infrastructure in the next generation of wireless connectivity.
Spatial Video Streaming on Apple Vision Pro XR Headset
2025
workshop
Apple recently unveiled capturing spatial video experiences on an iPhone and their extended reality (XR) headset Vision Pro. Spatial videos can be viewed on immersive near-eye displays like the Apple Vision Pro for a more realistic experience with depth perception. However, streaming spatial videos encounters several challenges, such as bandwidth limitations, latency, and synchronization issues between multiple camera views. This position paper presents a comprehensive research agenda to address these issues and make spatial video streaming as ubiquitous as traditional online video for mobile systems and applications. We outline several research threads for exploration and discuss a series of novel ideas, including view-adaptive streaming strategies, multipath support, and QoE modeling, which we believe will become the fundamental components for future video experiences on mobile and wearable devices.
Poster: A First Look at Apple's Stereoscopic Video and its Potential in Live Video Streaming for XR Headsets
2024
poster
With the evolution of stereoscopic video technology, live video streaming stands at the threshold of a more engaging and immersive future. Apple's recent innovations in video and Extended Reality (XR) technologies have paved the way for immersive live video experiences. This work characterizes Apple's spatial video and explores its potential in live video streaming, providing insights into the future of video streaming applications.
The Power of Asynchronous SLAM in Multi-User AR over Cellular Networks: A Measurement Study
2023
workshop
With the rapid deployment of 5G, an important question is whether 5G can support latency-critical apps such as multi-user AR, which allows multiple users to interact in the same physical space in real time. Recent studies showed that a popular multi-user cloud-based AR app (Cloud Anchor) suffers long end-to-end (E2E) latency in multi-user interactions under both LTE or 5G and hence cannot be supported by today's cellular networks. In this paper, we revisit the feasibility of multi-user AR over wireless networks by experimenting with another popular multi-user AR app, Just a Line, and find that its E2E latency is in the order of a few 100s of ms over both LTE and 5G, making real-time multi-user interactions feasible. We conduct a detailed measurement study of the Just a Line app over cellular networks and uncover the drastic user-perceived performance difference between the two multi-user apps stems from two fundamentally different architecture designs of performing SLAM: asynchronous vs. synchronous updates.