publications | Ahmad Hassan

2024

CONEXT

Wixor: Dynamic TDD Policy Adaptation for 5G/xG Networks

Ahmad Hassan, Shivang Aggarwal, Mohamed Ibrahim, and 2 more authors

In Proceedings of the ACM CoNEXT 2024 Conference, 2024

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SIGCOMM

Dissecting Carrier Aggregation in 5G Networks: Measurement, QoE Implications and Prediction

Wei Ye, Xinyue Hu, Steven Sleder, and 9 more authors

In Proceedings of the ACM SIGCOMM 2024 Conference, Sydney, NSW, Australia, 2024

@inproceedings{10.1145/3651890.3672251,
  author = {Ye, Wei and Hu, Xinyue and Sleder, Steven and Zhang, Anlan and Dayalan, Udhaya Kumar and Hassan, Ahmad and Fezeu, Rostand A. K. and Jajoo, Akshay and Lee, Myungjin and Ramadan, Eman and Qian, Feng and Zhang, Zhi-Li},
  title = {Dissecting Carrier Aggregation in 5G Networks: Measurement, QoE Implications and Prediction},
  year = {2024},
  isbn = {9798400706141},
  publisher = {Association for Computing Machinery},
  address = {New York, NY, USA},
  url = {https://doi.org/10.1145/3651890.3672250},
  doi = {10.1145/3651890.3672250},
  booktitle = {Proceedings of the ACM SIGCOMM 2024 Conference},
  pages = {340–357},
  numpages = {18},
  keywords = {carrier aggregation, 4G, 5G, network measurement, mobile network throughput prediction, deep learning},
  location = {Sydney, NSW, Australia},
  series = {ACM SIGCOMM '24},
}

NSDI

Habitus: Boosting Mobile Immersive Content Delivery through Full-body Pose Tracking and Multipath Networking

Anlan Zhang, Chendong Wang, Yuming Hu, and 5 more authors

In 21st USENIX Symposium on Networked Systems Design and Implementation (NSDI 24), Apr 2024

Bib PDF

@inproceedings{295677,
  author = {Zhang, Anlan and Wang, Chendong and Hu, Yuming and Hassan, Ahmad and Zhang, Zejun and Han, Bo and Qian, Feng and Xu, Shichang},
  title = {Habitus: Boosting Mobile Immersive Content Delivery through Full-body Pose Tracking and Multipath Networking},
  booktitle = {21st USENIX Symposium on Networked Systems Design and Implementation (NSDI 24)},
  year = {2024},
  isbn = {978-1-939133-39-7},
  address = {Santa Clara, CA},
  pages = {1677--1695},
  url = {https://www.usenix.org/conference/nsdi24/presentation/zhang-anlan},
  publisher = {USENIX Association},
  month = apr,
}

HotMobile
The Case for Boosting Mobile Application QoE via Smart Band Switching in 5G/xG Networks

Ahmad Hassan, Wei Ye, Anlan Zhang, and 6 more authors

In Proceedings of the 25th International Workshop on Mobile Computing Systems and Applications, San Diego, CA, USA, Apr 2024

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5G and future 6G networks support diverse combinations of access technologies, architectures, and radio frequencies, with each combination termed as a "band" henceforth. Through comprehensive measurements in 12 cities across 5 countries, we experimentally show that operator-configured default bands are often highly sub-optimal, particularly under mobility. We then propose smart band switching, where a UE’s band can be dynamically changed to improve the network performance and boost the application QoE. We discuss challenges, opportunities, and design choices for building a practical smart band switching system. We further develop preliminary UE-side band-switching logic on commodity smartphones, and evaluate it on commercial 5G networks.
@inproceedings{10.1145/3638550.3641132, author = {Hassan, Ahmad and Ye, Wei and Zhang, Anlan and Carpenter, Jason and Zhu, Ruiyang and Jin, Shuowei and Qian, Feng and Mao, Z. Morley and Zhang, Zhi-Li}, title = {The Case for Boosting Mobile Application QoE via Smart Band Switching in 5G/xG Networks}, year = {2024}, isbn = {9798400704970}, publisher = {Association for Computing Machinery}, address = {New York, NY, USA}, url = {https://doi.org/10.1145/3638550.3641132}, doi = {10.1145/3638550.3641132}, booktitle = {Proceedings of the 25th International Workshop on Mobile Computing Systems and Applications}, pages = {127–132}, numpages = {6}, keywords = {band switching, band selection, network measurement, mobile QoE, band, radio bands}, location = {San Diego, CA, USA}, series = {HOTMOBILE '24}, }
MMSys
OASIS: Collaborative Neural-Enhanced Mobile Video Streaming

Shuowei Jin, Ruiyang Zhu, Ahmad Hassan, and 5 more authors

In Proceedings of the 15th ACM Multimedia Systems Conference, Bari, Italy, Apr 2024

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Neural-enhanced video streaming (e.g., super-resolution) is an ongoing revolution which can provide extremely high-quality video streaming services breaking the restriction of bandwidth. However, such enhancements require intense computation power that is not affordable for a single mobile device, which hinders their real-world deployment. To address the limitation, we propose OASIS, the first system that facilitates multiple users in close proximity to execute intense neural-enhanced video streaming in realtime. To this end, OASIS intelligently distributes computation tasks among multiple mobile devices, selects appropriate video bitrates and super-resolution models, and optimizes video chunk delivery. As a result, the expensive neural-enhanced streaming is done through distributed collaboration, achieving optimal quality of experience (QoE). We implement and evaluate OASIS on commodity smartphones from different vendors, under various network and computation conditions. Extensive experiments demonstrate the high efficiency of OASIS: it improves the video streaming QoE by 40%-200% and reduces each participant’s energy consumption by 60% when the system scales up from a single device to six devices.
@inproceedings{10.1145/3625468.3647610, author = {Jin, Shuowei and Zhu, Ruiyang and Hassan, Ahmad and Zhu, Xiao and Zhang, Xumiao and Mao, Z. Morley and Qian, Feng and Zhang, Zhi-Li}, title = {OASIS: Collaborative Neural-Enhanced Mobile Video Streaming}, year = {2024}, isbn = {9798400704123}, publisher = {Association for Computing Machinery}, address = {New York, NY, USA}, url = {https://doi.org/10.1145/3625468.3647610}, doi = {10.1145/3625468.3647610}, booktitle = {Proceedings of the 15th ACM Multimedia Systems Conference}, pages = {45–55}, numpages = {11}, keywords = {Video streaming, deep neural networks, mobile computing, super-resolution}, location = {Bari, Italy}, series = {MMSys '24}, }
WWW
QUIC is not Quick Enough over Fast Internet

Xumiao Zhang, Shuowei Jin, Yi He, and 4 more authors

In Proceedings of the ACM on Web Conference 2024, Singapore, Singapore, Apr 2024

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QUIC is expected to be a game-changer in improving web application performance. In this paper, we conduct a systematic examination of QUIC’s performance over high-speed networks. We find that over fast Internet, the UDP+QUIC+HTTP/3 stack suffers a data rate reduction of up to 45.2% compared to the TCP+TLS+HTTP/2 counterpart. Moreover, the performance gap between QUIC and HTTP/2 grows as the underlying bandwidth increases. We observe this issue on lightweight data transfer clients and major web browsers (Chrome, Edge, Firefox, Opera), on different hosts (desktop, mobile), and over diverse networks (wired broadband, cellular). It affects not only file transfers, but also various applications such as video streaming (up to 9.8% video bitrate reduction) and web browsing. Through rigorous packet trace analysis and kernel- and user-space profiling, we identify the root cause to be high receiver-side processing overhead, in particular, excessive data packets and QUIC’s user-space ACKs. We make concrete recommendations for mitigating the observed performance issues.
@inproceedings{10.1145/3589334.3645323, author = {Zhang, Xumiao and Jin, Shuowei and He, Yi and Hassan, Ahmad and Mao, Z. Morley and Qian, Feng and Zhang, Zhi-Li}, title = {QUIC is not Quick Enough over Fast Internet}, year = {2024}, isbn = {9798400701719}, publisher = {Association for Computing Machinery}, address = {New York, NY, USA}, url = {https://doi.org/10.1145/3589334.3645323}, doi = {10.1145/3589334.3645323}, booktitle = {Proceedings of the ACM on Web Conference 2024}, pages = {2713–2722}, numpages = {10}, keywords = {http, network measurement, quic, transport, web performance}, location = {Singapore, Singapore}, series = {WWW '24}, }

2023

IMC
Poster: QUIC is not Quick Enough over Fast Internet

Xumiao Zhang, Shuowei Jin, Yi He, and 4 more authors

In Proceedings of the 2023 ACM on Internet Measurement Conference, Montreal QC, Canada, Apr 2023

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QUIC is a multiplexed transport-layer protocol over UDP and comes with enforced encryption. It is expected to be a game-changer in improving web application performance. Together with the network layer and layers below, UDP, QUIC, and HTTP/3 form a new protocol stack for future network communication, whose current counterpart is TCP, TLS, and HTTP/2. In this study, to understand QUIC’s performance over high-speed networks and its potential to replace the TCP stack, we carry out a series of experiments to compare the UDP+QUIC+HTTP/3 (QUIC) stack and the TCP+TLS+HTTP/2 (HTTP/2) stack. Preliminary measurements on file download reveal that QUIC suffers from a data rate reduction compared to HTTP/2 across different hosts.
@inproceedings{10.1145/3618257.3625002, author = {Zhang, Xumiao and Jin, Shuowei and He, Yi and Hassan, Ahmad and Mao, Z. Morley and Qian, Feng and Zhang, Zhi-Li}, title = {Poster: QUIC is not Quick Enough over Fast Internet}, year = {2023}, isbn = {9798400703829}, publisher = {Association for Computing Machinery}, address = {New York, NY, USA}, url = {https://doi.org/10.1145/3618257.3625002}, doi = {10.1145/3618257.3625002}, booktitle = {Proceedings of the 2023 ACM on Internet Measurement Conference}, pages = {730–731}, numpages = {2}, keywords = {http/3, internet measurement, quic, transport protocol}, location = {Montreal QC, Canada}, series = {IMC '23}, }
PAM

An In-Depth Measurement Analysis of 5G mmWave PHY Latency and its Impact on End-to-End Delay

Rostand A. K. Fezeu, Eman Ramadan, Wei Ye, and 8 more authors

In Passive and Active Measurement, Apr 2023

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2022

SIGCOMM
Vivisecting Mobility Management in 5G Cellular Networks

Ahmad Hassan, Arvind Narayanan, Anlan Zhang, and 7 more authors

In Proceedings of the ACM SIGCOMM 2022 Conference, Amsterdam, Netherlands, Apr 2022

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With 5G’s support for diverse radio bands and different deployment modes, e.g., standalone (SA) vs. non-standalone (NSA), mobility management - especially the handover process - becomes far more complex. Measurement studies have shown that frequent handovers cause wild fluctuations in 5G throughput, and worst, service outages. Through a cross-country (6,200 km+) driving trip, we conduct in-depth measurements to study the current 5G mobility management practices adopted by three major U.S. carriers. Using this rich dataset, we carry out a systematic analysis to uncover the handover mechanisms employed by 5G carriers, and compare them along several dimensions such as (4G vs. 5G) radio technologies, radio (low-, mid- & high-)bands, and deployment (SA vs. NSA) modes. We further quantify the impact of mobility on application performance, power consumption, and signaling overheads. We identify key challenges facing today’s NSA 5G deployments which result in unnecessary handovers and reduced coverage. Finally, we design a holistic handover prediction system Prognos and demonstrate its ability to improve QoE for two 5G applications 16K panoramic VoD and realtime volumetric video streaming. We have released the artifacts of our study at https://github.com/SIGCOMM22-5GMobility/artifact.
@inproceedings{hassan2022vivisecting, author = {Hassan, Ahmad and Narayanan, Arvind and Zhang, Anlan and Ye, Wei and Zhu, Ruiyang and Jin, Shuowei and Carpenter, Jason and Mao, Z. Morley and Qian, Feng and Zhang, Zhi-Li}, title = {Vivisecting Mobility Management in 5G Cellular Networks}, year = {2022}, isbn = {9781450394208}, publisher = {Association for Computing Machinery}, address = {New York, NY, USA}, url = {https://doi.org/10.1145/3544216.3544217}, doi = {10.1145/3544216.3544217}, booktitle = {Proceedings of the ACM SIGCOMM 2022 Conference}, pages = {86--100}, numpages = {15}, keywords = {coverage, 5G, dataset, energy, handover, mobility, handover prediction, mobility management, network measurement, application performance}, location = {Amsterdam, Netherlands}, series = {SIGCOMM '22}, talk = {https://dl.acm.org/doi/10.1145/3544216.3544217}, }
INFOCOM
A Comparative Measurement Study of Commercial 5G mmWave Deployments

Arvind ^*Narayanan, Muhammad Iqbal ^*Rochman, Ahmad Hassan, and 5 more authors

In IEEE INFOCOM 2022 - IEEE Conference on Computer Communications, Apr 2022

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5G-NR is beginning to be widely deployed in the mmWave frequencies in urban areas in the US and around the world. Due to the directional nature of mmWave signal propagation, improving performance of such deployments heavily relies on beam management and deployment configurations. We perform detailed measurements of mmWave 5G deployments by two major commercial 5G operators in the US in two diverse environments: an open field with a baseball park and a downtown urban canyon region, using smartphone-based tools that collect detailed measurements across several layers (PHY, MAC and up) such as beam-specific metrics like signal strength, beam switch times, and throughput per beam. Our measurement analysis shows that the parameters of the two deployments differ in a number of aspects: number of beams used, number of channels aggregated, and density of deployments, which reflect on the throughput performance. Our measurement-driven propagation analysis demonstrates that narrower beams experience a lower path-loss exponent than wider beams, which combined with up to eight frequency channels aggregated on up to eight beams can deliver a peak throughput of 1.2 Gbps at distances greater than 100m.
@inproceedings{narayanan2022mmwave, author = {Narayanan, Arvind and Rochman, Muhammad Iqbal and Hassan, Ahmad and Firmansyah, Bariq S. and Sathya, Vanlin and Ghosh, Monisha and Qian, Feng and Zhang, Zhi-Li}, booktitle = {IEEE INFOCOM 2022 - IEEE Conference on Computer Communications}, title = {A Comparative Measurement Study of Commercial 5G mmWave Deployments}, year = {2022}, pages = {800-809}, doi = {10.1109/INFOCOM48880.2022.9796693}, }

2021

SIGCOMM
A Variegated Look at 5G in the Wild: Performance, Power, and QoE Implications

Arvind ^*Narayanan, Xumiao ^*Zhang, Ruiyang Zhu, and 9 more authors

In Proceedings of the 2021 ACM SIGCOMM 2021 Conference, Virtual Event, USA, Apr 2021

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Motivated by the rapid deployment of 5G, we carry out an in-depth measurement study of the performance, power consumption, and application quality-of-experience (QoE) of commercial 5G networks in the wild. We examine different 5G carriers, deployment schemes (Non-Standalone, NSA vs. Standalone, SA), radio bands (mmWave and sub 6-GHz), protocol configurations (_e.g._ Radio Resource Control state transitions), mobility patterns (stationary, walking, driving), client devices (_i.e._ User Equipment), and upper-layer applications (file download, video streaming, and web browsing). Our findings reveal key characteristics of commercial 5G in terms of throughput, latency, handover behaviors, radio state transitions, and radio power consumption under the above diverse scenarios, with detailed comparisons to 4G/LTE networks. Furthermore, our study provides key insights into how upper-layer applications should best utilize 5G by balancing the critical tradeoff between performance and energy consumption, as well as by taking into account the availability of both network and computation resources. We have released the datasets and tools of our study at https://github.com/SIGCOMM21-5G/artifact.
@inproceedings{narayanan2021variegated, author = {Narayanan, Arvind and Zhang, Xumiao and Zhu, Ruiyang and Hassan, Ahmad and Jin, Shuowei and Zhu, Xiao and Zhang, Xiaoxuan and Rybkin, Denis and Yang, Zhengxuan and Mao, Zhuoqing Morley and Qian, Feng and Zhang, Zhi-Li}, title = {A Variegated Look at 5G in the Wild: Performance, Power, and QoE Implications}, year = {2021}, isbn = {9781450383837}, publisher = {Association for Computing Machinery}, address = {New York, NY, USA}, url = {https://doi.org/10.1145/3452296.3472923}, doi = {10.1145/3452296.3472923}, booktitle = {Proceedings of the 2021 ACM SIGCOMM 2021 Conference}, pages = {610--625}, numpages = {16}, keywords = {video streaming, mmWave, power characteristics, network measurement, power model, dataset, energy efficiency, latency, 5G}, location = {Virtual Event, USA}, series = {SIGCOMM '21}, talk = {https://dl.acm.org/doi/10.1145/3452296.3472923} }