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Course Project Book (Mobile Computing and Wireless Networks) CS 395T – Spring 2001


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Title: Course Project Book (Mobile Computing and Wireless Networks) CS 395T – Spring 2001

Course Project Book (Mobile Computing and
Wireless Networks) CS 395T Spring 2001
  • Course Instructor
  • Dr. Yongguang Zhang (
  • Course URL http//
  • May 16, 2001

  • Project List
  • Mobile IP service for ACES and TAY
  • Location Service for Mobile Device
  • Linux Kernel Support for Ad-hoc Routing
  • Linux Kernel Module for Ad-hoc Routing
  • Multi-Mode TCP for Wireless Networks
  • Equation-Based TCP Window Adjustment
  • TCP Performance for Ad Hoc Networks
  • Ad Hoc IP Routing over Bluetooth Scatternets
  • Scalable DNS for Mobile Computing
  • Active Ad Hoc Networking
  • Energy-Aware Routing in Ad Hoc Networks
  • Transparent Migration of Mobile Agents
  • Service Discovery in Wireless Networks

Mobile IP service for ACES and TAY
  • New Ideas
  • Achieving smooth handoff while roaming between
    different 802.11 wireless LANs operated in
    infrastructure point mode using mobile IP.
  • Algorithm to determine change of network
  • Guessing the network change based on three missed
    beacon (registration request).
  • Guessing network change based on signal strength
  • Based on users input
  • Project Goals
  • Implement deploy of Mobile IP in CS Network.
  • Determining best location for home agent and
    foreign agent.
  • Study best mode of operation for mobile node
    (co-located COA or FA assigned COA) to achieve
    smooth handoff.
  • Auto configuration of mobile node when network
    change is detected.
  • Results/Lesson Learned
  • Experimental Mobile IP is operational in CS
  • Our Algorithm helped to achieve semi-smooth
    handoff while moving between ACES and TAY
    wireless network (30 sec approx).
  • Lesson learned
  • 802.11 does not have good support for mobile IP
    smooth handoff in infrastructure mode.
  • No easy heuristics to determine network change
    (layer2) in 802.11 access point mode.

Project team Madhusudan Kayastha, John
Thomas URL http//
Location Service for Mobile Device
  • New Ideas
  • Increasing proliferation of 802.11 base stations
    and PC card ? use 802.11 wireless LAN
    infrastructure to determine mobile device
    location inside building
  • Signal strength can be measured and there is a
    correlation between signal strength and distance
  • Signal strengths from multiple base stations can
    triangulate the exact location
  • Key Design/Approach
  • Data collation mapping the service area in
    advance for an accurate signal map
  • Algorithm 1 best matching O(n2)
  • Algorithm 2 multidimensional search O(log(n))
  • GUI (see above)
  • Limitation Placement of Base stations limited
    to certain locations
  • Results/Lesson Learned
  • Implemented in Linux
  • Tested in ACES 6th floor
  • Beacon stations 2
  • Service granularity 10 feet
  • Accuracy 90 of the time within 15 feet
  • Lesson learned
  • 802.11 Linux driver does not support
    promiscuous mode to pick up beacons from
    multiple base stations
  • Resolved to ad-hoc mode

Project team Ravishankar Chamarajnagar, Jeff
Napper URL http//
Linux Kernel Support for Ad-hoc Routing
  • New Ideas
  • Many Ad-hoc Routing Protocols Exist
  • Very few real implementations
  • High Complexity
  • Not enough tools for development
  • Performance claims based on simulation results
  • Designed and developed a generic infrastructure
  • Provides a tool to evaluate Ad-hoc protocols

NIM Network Interface Module UIM User Interface
AKMAd-hoc Kernel Module AUD Ad-hoc User
Daemon ART Ad-hoc Routing Table
  • Design
  • Generic Interface for all ad-hoc routing
  • Network Interface Module (NIM)
  • User Interface Module (UIM)
  • NIM Interface to Network Stack
  • AKM In Data Plane
  • Forwarding according to Ad-hoc protocol
  • UIM for data and control plane commn.
  • AUD In Control Plane
  • Ad-hoc Route maintenance
  • Implementation Testing
  • Implemented in Linux 2.4.3
  • Used Netfilter IPTable support
  • Tested multihop routing
  • Three hosts in broadcast setup
  • Test Protocols
  • Manual Configuration
  • AODV
  • Can be extended to support multiple protocols

Project team Puneet Chopra, Sumit Garg, Sugat
Jain URL http//
Linux Kernel Module for Ad-hoc Routing
  • New Ideas
  • Provide an architecture for ad hoc routing
    protocol implementation by extracting the common
    part, like multihop for packet delivery,
    reliable link layer maintenance, etc into general
    kernel module.
  • Design
  • Function separation between user and kernel
  • Necessary communication overload between user and
    kernel are reduced to minimum
  • Implementation Testing
  • Kernel on top of Linux 2.4.2
  • Two hosts can talk to each other
  • Communication between user and kernel are tested
  • AODV user daemon implemented
  • Other protocol implementation are extendable

Project team Zhenxun Xiao, Wei Li, Minesh
Shilotri URL http//
Multi-Mode TCP for Wireless Networks
  • New Ideas
  • TCP manages multiple modes
  • A mode is a subset of entire TCP state
  • corresponds to an overlay network
  • dynamic
  • TCP is notified of the handoff events
  • TCP switches between modes when the mobile host
    vertical handoffs between different overlay
  • Different actions for upward and downward handoffs
  • Motivation
  • TCP has been tuned to traditional networks
    comprising wired links and stationary hosts
  • Wireless overlay networks
  • Heterogeneous overlays
  • User mobility vertical handoffs
  • Sudden, frequent, and significant changes in
    bandwidth and delay
  • Study TCP behavior over wireless overlay networks
    and improve its performance
  • Key Design/Approach
  • A mode includes cwnd, ssthresh, rtt, srtt,
    rttvar, rtxcur, etc.
  • Generally, save the current mode and load a new
    mode for a vertical handoff
  • Schedule a handoff timer for a downward handoff
    to avoid fast retransmission caused by
    out-of-order delivery
  • Reset mode for an upward handoff to an unvisited
    overlay network
  • An extension to New-reno TCP
  • Results/Lesson Learned
  • Implemented in ns2
  • Simulation results in ns2
  • Eliminate unnecessary retransmissions caused by
    timeouts or duplicate acks
  • TCP goodput improved (gt 7)
  • Lesson learned
  • Implementation of TCP stack
  • Limitation of the simulation
  • Need of more realistic experiments

Project team Fengfeng Tu, Hongxia Tian URL
Equation-Based TCP Window Adjustment
  • Design
  • Objective fast estimation of congestion window
  • Node i keeps its own congestion loss rate pi
  • TCP packet has an additional field, FP
    (Forwarding Probability).
  • FP is initially set to 1 , and multiplied by 1-pi
    at each intermediate node i.
  • Receiver reports FP to the sender with ACK.
  • Congestion window is calculated from the path
    loss rate p 1-FP
  • Problem
  • Packet corruption caused by wireless transmission
  • Caching and retransmission at base station.
  • Each node in ad hoc network doesnt have enough
  • Link failure due to mobility
  • Explicit notification freeze TCP states until
    new route found.
  • Old states may not be appropriate for new route.

Results 2
Results 1
Project team Min Sik Kim, Eunjin Jung URL
TCP Performance for Ad Hoc Networks
  • Simulation Setup
  • Using NS2
  • 20 mobile nodes
  • 500x500 grid
  • 6 different levels of moving speed
  • Single and multiple connections traffic pattern
  • Problem
  • What is the performance of TCP over an ad hoc
    network, under each of the four ad hoc network
    routing protocols?
  • DSR
  • AODV
  • DSDV
  • TORA

  • Conclusion
  • DSR and DSDV is the best
  • AODV is not as good
  • TORA is far worst

Project team Feng Wang, Zhiwei Lin URL
Ad Hoc IP Routing over Bluetooth Scatternets
  • New Ideas
  • A new architecture for IP networking in bluetooth
  • Current standard (LAN profile, BNEP) does not
    tackle inter-piconet IP networking issue
  • Cluster-based on-demand routing strategy
  • Master Relay Switch Routing (MRSR) protocol for
    inter-piconet IP forwarding
  • Key Design/Approach
  • IP networking for bluetooth scatternet
  • Piconet bridging scheme
  • Each scatternet as one IP network
  • Host based addressing
  • Master Relay Switch Routing (MRSR)
  • Ad-hoc routing in scatternet
  • based on AODV
  • Results/Lesson Learned
  • Implemented in NS2
  • Extension to IBM BlueHoc

Project team Sidharth Choudhury, Anupam
Rastogi URL http//
Scalable DNS for Mobile Computing
  • DNS Workload Analysis
  • 4.5 in number, 0.8 in bandwidth
  • 80 absorbed at client cache
  • 70 absorbed at name servers
  • 94 absorbed by cache
  • Problem if no cache
  • Motivation
  • Using DNS as location service infrastructure for
    mobile computing
  • Dynamic updates are already defined in RFCs
  • No caching?
  • Scalability?

Key Design/Approach
  • Results/Lesson Learned
  • Importance of smart caching scheme
  • Scalability of DNS can be achieved from server
  • Update individual hosts instead of zones

Project team Dong-Young Lee , Bong-Soo
Sohn URL http//
Active Ad Hoc Networking
  • New Ideas
  • Dynamic Ad Hoc Routing Protocols implemented in
    an active networking test-bed
  • Dynamic Protocol Dissemination using mobile code
  • Provides Increased adaptability to unpredictable
    Ad Hoc environment

Active (FastNet) Node
Active (FastNet) Node
Remote Evaluation
Code Pushing
Active (FastNet) Node
  • Key Design / Approach
  • DSR(basic, optimized, multipath), AODV, and TORA
    protocols implemented
  • Node Resident Service functions for basic
    protocol operations (coded in Popcorn)
  • Protocols (really mobile glue code) implemented
    in PLAN
  • Dynamic Linking of protocol modules
  • Limitation
  • Due to lack of concurrency in FASTNet, only Route
    Discovery protocol is implemented. Route
    Maintenance is emulated.
  • Results / Lessons Learned
  • Implemented in FASTNet PLAN (Linux)
  • Choose routing protocols adaptively.
  • Lessons learned
  • AN can provide dynamic efficient routing
    protocols for MANET
  • Decision-making mechanism for optimal protocol in
    each environment is needed
  • Need to extend this idea in test-bed system

Project team Seong-Kyu Song, Stephen
Shannon URL http//
Energy-Aware Routing in Ad Hoc Networks
  • Motivation
  • Mobile nodes are battery-operated and one or
    several nodes energy exhaustion may cause the
    disruption of the entire network
  • A number of approaches focus on minimizing the
    total consumed power.
  • Several approaches goal was to maximize the life
    time of the system. However, these are based on
    static topology and given traffic demands in
  • Our goal is to propose energy-aware routing
    algorithms in dynamic ad hoc network environments
    to achieve max. system lifetime.
  • Routing Algorithms
  • Maxmin routing algorithm choose the path whose
    minimum energy level node has the maximum value
    among all paths.
  • Maxmax routing algorithm choose the path which
    has maximal residual energy on the path
  • Maxavg routing algorithm choose the path which
    has maximal average energy level
  • Shortest path routing algorithm no energy
  • Simulation Setup
  • Single source-destination pair without node
  • Single source-destination pair with node mobility
  • Multiple source-destination pairs without node
  • Multiple source-destination pairs with node
  • Introduction of energy balance factor which
    represents the heterogeneity of initial energy
    level at each node
  • Results/Lesson Learned
  • Overall our Maxmin algorithm performs well.
  • One example of results
  • Simulation techniques such as generating topology
    and random traffic etc.
  • Obtain a research trend of energy-aware design in
    mobile computing environments

Project team Jangwon Lee Xiangying Yang URL
Transparent Migration of Mobile Agents
  • New Ideas
  • Transform mobile agent byte-code to support
    transparent migration
  • Simulate thread and stack frame to support saving
    and restoring call stack and local variables
  • Mechanism for surviving migration failure which
    provides more reliable disconnected operation
  • Design/Approach
  • Provide a Java mobile agent system that supports
    transparent migration
  • Use standard JVM to gain better acceptance
  • Use byte-code instead of source code
  • Results/Lesson Learned
  • Developed API, parser, and server for mobile
    agent programming and deployment
  • With transparent migration, mobile agent
    programming is more intuitive
  • Demonstrate typical mobile agents applications
    using our framework

Project team Endi S. Dewata, Kiran K.
Adduri URL http//
Service Discovery in Wireless Networks
  • New Ideas
  • A Jini-based Multimedia Services Application
    designed for ad hoc wireless systems.
  • Use of multicast-based service discovery
    protocols for multimedia services in ad hoc
    wireless networks.
  • Adapt to changes in bandwidth in wireless overlay
  • Provide value-added services to roaming users
    with minimal configuration.
  • Integrated user accountability for services.

Lookup Service
Multicast in a Jini-enabled wireless network
Java-based Client GUI
Multimedia Provider
Service URL
Microsoft Access
  • Key Design / Approach
  • Component-based technologies.
  • Multimedia Services Application
  • Multimedia Client Plays multimedia files from
    Service URLs using JMF.
  • Multimedia Service Provider Provides Service
    URLs to clients, interfaces to user database.
  • Reggie (The Service Lookup by Sun Microsystems)
    Keeps track of available services.
  • User Database (Microsoft Access connected to
    Service Provider via ODBC and JDBC)
  • Results / Lessons Learned
  • Service discovery is crucial in emerging
    packet-based wireless technologies (3G/4G,
  • Lessons learned
  • Holding users accountable for using wireless
    bandwidth for value-added services is necessary.
  • Key challenge Integrating various enabling
    technologies (Jini, JMF, JDBC, etc.)

Project team Dogu Arifler, Vivek Sharma URL
  • Contact
  • Prof. Yongguang Zhang
  • Dept. of Computer Sciences
  • University of Texas at Austin
  • Austin, Texas 78712, U.S.A.
  • E-mail
  • Phone 512-232-7889