Ahmad Hassan

Selected Publications

1. NSDI

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

   Zhang, Anlan, Wang, Chendong, Hu, Yuming,  Hassan, Ahmad, Zhang, Zejun, Han, Bo, Qian, Feng, and Xu, Shichang

   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,
     abbr = {NSDI},
     selected = {true},
     bibtex_show = {true},
     pdf = {habitus_nsdi24.pdf}
   }

2. HotMobile

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

   Hassan, Ahmad, Ye, Wei, Zhang, Anlan, Carpenter, Jason, Zhu, Ruiyang, Jin, Shuowei, Qian, Feng, Mao, Z. Morley, and Zhang, Zhi-Li

   In Proceedings of the 25th International Workshop on Mobile Computing Systems and Applications Apr 2024

   Abs Bib PDF

   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},
     abbr = {HotMobile},
     selected = {true},
     bibtex_show = {true},
     pdf = {bandswitching_hotmobile24.pdf}
   }

3. SIGCOMM

   Vivisecting Mobility Management in 5G Cellular Networks

   Hassan, Ahmad, Narayanan, Arvind, Zhang, Anlan, Ye, Wei, Zhu, Ruiyang, Jin, Shuowei, Carpenter, Jason, Mao, Z. Morley, Qian, Feng, and Zhang, Zhi-Li

   In Proceedings of the ACM SIGCOMM 2022 Conference Apr 2022

   Abs Bib PDF Talk Slides Website

   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},
     abbr = {SIGCOMM},
     selected = {true},
     bibtex_show = {true},
     website = {https://github.com/SIGCOMM22-5GMobility/artifact},
     pdf = {vivisectingmobility_sigcomm22.pdf},
     talk = {https://dl.acm.org/doi/10.1145/3544216.3544217},
     slides = {slides-sig22-mobility-public.pptx}
   }

4. SIGCOMM

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

   *Narayanan, Arvind, *Zhang, Xumiao, Zhu, Ruiyang,  Hassan, Ahmad, Jin, Shuowei, Zhu, Xiao, Zhang, Xiaoxuan, Rybkin, Denis, Yang, Zhengxuan, Mao, Zhuoqing Morley, Qian, Feng, and Zhang, Zhi-Li

   In Proceedings of the 2021 ACM SIGCOMM 2021 Conference Apr 2021

   Abs Bib PDF Code Talk

   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},
     selected = {true},
     bibtex_show = {true},
     abbr = {SIGCOMM},
     code = {https://github.com/SIGCOMM21-5G/artifact.git},
     pdf = {avariegatedlookat5g_sigcomm21.pdf},
     talk = {https://dl.acm.org/doi/10.1145/3452296.3472923}
   }