Research Projects in the Mobile Computing and Networking (MCN) Lab

Guohong Cao Department of Computer Science and Engineering

The Pennsylvania State Universityhttp://www.cse.psu.edu/~gcao

Mobile Computing and Networking (MCN) Lab• MCN lab conducts research in many areas of wireless

networks and mobile computing, emphasis on designing and evaluating mobile systems, protocols, and applications.– Current Projects: smartphones, wireless network security, data

dissemination/access in wireless P2P networks, vehicular networks, wireless sensor networks, resource management in wireless networks.

– Support: NSF (CAREER, ITR, NeTS, NOSS, CT, CNS), Army Research Office, NIH, DoD/Muri, DoD/DTRA, PDG/TTC and member companies Cisco, Narus, Telcordia, IBM and 3ETI.

• Current students:– 10 PhD students– 1 PostDoc– 3 visiting scholars

Alumni• 15 PhDs

Hao Zhu (8/2004), Qualcomm. Liangzhong Yin (12/2004), Microsoft. Wensheng Zhang (8/2005), Associate Professor, Iowa State University Hui Song (8/2007), Assistant Professor, Frostburg State University Jing Zhao (8/2008), Cisco Systems. Min Shao (12/2008), Microsoft Changlei Liu (5/2010), UMUC Yang Zhang (2/2011), Palo Alto Networks. Baojun Qiu (Co-chaired with J. Yen) 8/2011, eBay. Bo Zhao (10/2011), AT&T. Zhichao Zhu (2/2012), Nokia. Qiang Zheng (5/2012), Google Wei Gao (5/2012), Assistant Professor, University of Tennessee. Qinghua Li (5/2013), Assistant Professor, University of Arkansas. Yi Wang (5/2013), Google.

• 12 MS students went to various companies• 5 visiting scholars

4

Outline

• Efficient Energy-Aware Web Access in Wireless Networks

• Social-Aware Data Dissemination in Delay Tolerant Networks

• Resilient and Efficient Data Access in Cognitive Radio Networks

• Privacy-Aware Mobile Sensing

5

Web Browsing in 3G/4G Networks

• Smartphones in 3G/4G networks:– Increasingly used to access the Internet– Consume more power

• Cellular interface consumes lots of energy– 30%-50% of total energy

• Current status:– 3G/4G radio interface always on, timer control– Radio resource is not released, reduce network

capacity

Characteristics of 3G Radio interface

T2 = 15 sec

T1 = 4 sec

Traffic Load of Opening Webpages

Radio interface is always on during data transmission

8

Reorder the Computation Sequence

• Reorganize the computation sequence of the web browser, so that it first runs the computations that will generate new data transmissions and retrieve these data from the web server. – Then, the web browser can put the 3G radio interface into low power

state, and then run the remaining computations.

Reducing the Energy of FACH State

• After a webpage is downloaded, predict the user reading time on the webpage– This time > a threshold (delay vs. power): switch into low power state– Prediction is based on Gradient Boosted Regression Trees (GBRT).

• Selected 10 features such as Data transmission time, webpage data size, figure size, no. of downloaded objects, etc.

• Also consider user interest.

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Evaluations

• The prototype:– Android Phones– T-Mobile 3G/UMTS network

• Implement the prototype and collect real traces• Experimental results:

– Reduce power consumption: 30%– Reduce loading time: 17%– Increase network capacity: 19%

Motivation

Power

t

Power

t

Power

t

Power

t

Power

t

How to reduce tail energy and promotion delay?

Promotion

Data transmission

Tail

Tail

Basic idea

• Aggregation traffics on one node (proxy)– How? An optimization problem.

• Forward via P2P (Bluetooth or WiFi direct)

Power

t

Power

t

Power

t

Power

t

Power

t

P2P interface

Proxy

Testbed Results

• Total energy saving rate: 30.4%• Average delay reducing rate: 31%

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Outline

• Efficient Energy-Aware Web Access in Wireless Networks

• Social-Aware Data Dissemination in Delay Tolerant Networks

• Resilient and Efficient Data Access in Cognitive Radio Networks

• Privacy-Aware Mobile Sensing

Data Dissemination in DTNs• Lack of infrastructure support in disaster recovery,

battlefield, environmental monitoring, etc. • Mobile devices can form mobile opportunistic

networks or Disruption Tolerant Networks (DTN).• General methodology: Carry-and-forward• The key issue is to select which node (relay) to

forward the data.

Japan tsunami 2010

Social-Aware Data Dissemination• Exploiting social relations among mobile nodes

for relay selections– Stable long-term characteristics compared to node

mobility– Centrality (Degree or betweenness), which shows the

importance of some nodes to help communications among other nodes. • High centrality nodes can be used as relay nodes.

– Community, i.e., nodes have common acquaintances have higher probabilities to know each other. • data can reach the destination easier if it reaches someone in

the same social community as the destination.

Our Results

• Social interest: User-Centric Data Dissemination in Disruption Tolerant Networks (infocom’11)

• Social Contact Patterns: On Exploiting Social Contact Patterns for Data Forwarding in Delay Tolerant Networks (icnp’10, TMC’13)

• Social selfishness: Routing in socially selfish disruption tolerant networks (infocom’10, Adhoc’12)

• Social-aware caching: Supporting Cooperative Caching in Disruption Tolerant Networks (icdcs’11, icdcs’12, TMC’13)

• Social relationship: Social-Aware Data Diffusion in Delay Tolerant MANETs (book chapter’12)

• Social-aware multicast: Social-aware Multicast in Disruption Tolerant Networks (Mobihoc’09, ToN’12)

Social Interest

• System development: recording users’ interests– Data access via Samsung Nexus S smartphones– Categorized web news from CNN

• Application scenarios– Public commute systems: bus, subway– Public event sites: stadium, shopping mall– Disaster recovery

Android

webpage XML format phone display

Social Interest

• User interests: dynamically updated by users’ activities• System execution

– 30 users at Penn State, 5-month period– 11 categories, 306,914 transceived, 40, 872 read by users

Contact

A

B

C

Social Contact

• System development– Testbed: TelosB sensors– Deployment: 1000+ sensors distributed to high school students

• Heterogeneity of centrality, community, high cluster coefficient• Flu immunization

A B

C

802.15.4/ZigBee compliant10kB RAM, 250kbps data rateTinyOS 2.0

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Outline

• Efficient Energy-Aware Web Access in Wireless Networks

• Social-Aware Data Dissemination in Delay Tolerant Networks

• Resilient and Efficient Data Access in Cognitive Radio Networks

• Privacy-Aware Mobile Sensing

Emergence of Cognitive Radio• Unlicensed use of licensed spectrum is approved by

government agencies– Cognitive radio – dynamically configure the operating

spectrum

Cognitive Radio Networks Dynamic spectrum access

Must avoid interference with primary users (licensed users) With infrastructure / without infrastructure (ad-hoc)

Our Work

Data Caching

• No caching

• Caching(delay is statistically bounded)

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Outline

• Efficient Energy-Aware Web Access in Wireless Networks

• Social-Aware Data Dissemination in Delay Tolerant Networks

• Resilient and Efficient Data Access in Cognitive Radio Networks

• Privacy-Aware Mobile Sensing

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Proliferation of Mobile Devices

• Mobile devices– Smartphone, tablet, vehicle,

medical device, pollution sensor

• Sensing capabilities– Camera, microphone,

accelerometer, GPS• Communication capabilities

– 3G/4G, WiFi, BluetoothA huge opportunity for mobile sensing

Obstacles in Collecting Sensing Data

• Privacy concern– Location, activity, health

• <location, noise>• <amount of exercise>

• Cost of participation– Power, bandwidth, human attention

• Lack of network connectivity– Devices without comms infrastructure (e.g., 3G)– Circumstances of unavailable or cost-inefficient

infrastructure

Research Summary

Obstacles

Privacy concern

Cost of participation

Lack of network

connectivity

Privacy-aware incentives

Solutions

Privacy-aware

incentive

Privacy-aware

aggregation

Secure opportunistic mobile networking

[PerCom’13] [ICNP’12,PETS’13]

[Infocom’10]: selfishness[TDSC’13]: flood attack[TIFS’12]: drop attack

More data collected from more users

More data collected from more devices

Summary• Efficient energy-aware web access in wireless networks

– reducing the power consumption of smartphones by dealing with the special characteristic of the 3G/4G radio interface

• Social-aware data dissemination in delay tolerant networks– Exploiting the knowledge of social contact patterns, social

interests, and social relationships. – Two testbeds for data collection.

• Resilient and efficient data access in cognitive radio networks– mitigating the effects of primary user appearance

• Privacy-aware mobile sensing