The Analysis of Multicastbased Handoff Scheme on the Mobile Network

1
The Analysis of Multicast-based Handoff Scheme
on the Mobile Network
Term Project (2000/12/06)

• Jiyeon Son, Jin-cheol Kim
• System Modeling Performance Analysis
• Final Presentation

2
Content

• Background
• Related Works
• Daedalus Model Overview
• Our Project Goal
• Implementing in NS
• Simulation
• Conclusion Future Work

3
Background

• Increase the popularity of Wireless/Mobile
  Network
• Internet Access through the Mobile Network
• Mobile Network Characteristics
• mobility, high BER, low B/W, power limit,,.
• Handoff issues
• occurs when mobile host moves between wireless
  cells
• can cause some data loss or large delay variation
• can lead to severe performance degradation of
  applications
• (real-time multimedia application / reliable
  transport protocols)

4
Background

• Multicast-based Handoff Scheme
• be proposed to minimize data loss or delay
• key idea
• Define a group of base stations including
• current cell of a mobile host
• cells that the mobile host is likely to visit
  next
• Address packets destined to the mobile host to
  the group

5
Our Motivation

• Multicast-based Handoff Scheme
• earlier research has been done by measuring in a
  simple real test-bed environment
• further studies are necessary for the impacts
  multicast-based handoff schemes on TCP or
  multimedia data traffic
• Scalability issue
• buffering overhead as the movement speed and
  number of users increases

6
Related Work

• R.Ghai 94
• Muticast-based Handoff scheme in picocellular
  network environment.
• 3-layer hierarchy Mobile host(MH), Base
  Station(BS), Supervisor Host (SH)
• Assign BSs to different multicast groups
• static multicast group groups is defined taking
  physical topology into account
• static definition may not take individual user
  mobility pattern into account

7
Related Work

• Seshan 96 Deadalus Project
• Dynamic multicast group of Base Stations
• by detecting nearby Base Station via Beacon
  signals.
• Each users group can be different
• Only one BS can Forward data to MH, while others
  just Buffer the multicast data.
• When Handoff, the old BS is requested to buffer
  data, and the new BS is requested to forward the
  stored data.

8
Related Work

• MSM-IP Mysore98
• Mobility Support using IP Multicasting
• (without help of IP routing)
• Assigns multicast address to each MH.
• Key Idea
• When moves to new network, MH sends Registration
  message to the local multicast router.
• The multicast router initiates a Join procedure
  to join the multicast distribution tree.
• MH stop sending membership refresh messages to
  old multicast router.
• Problem each MH be assigned unique multicast
  IP address individually.

9

Project Goal

• Analysis of multicast-based handoff scheme
• Explore the Performance Issues
• Explore the effects of the performance
  parameters, such as Number of Users,
  Mobility Speed, Buffer Size, and the Beacon
  periods.
• Explore the possibility of improvement
• Examine in the aspect of scalability issue
• Examine the effect of the Beacon Time-base
  Offsets between neighbor cells.
• Adopt the Daedalus model Seshan 96
• Why? Daedalus scheme is focused on the handoff
  mechanism and its procedure is well described.

10
Daedalus Model Overview
11
Daedalus Model Overview

• Operational Model
• Two Stage Routing
• First stage Packets are delivered to the Home
  Agent.
• Second stage Differs from the Mobile IP, where
  the Home Agent forwards the packet using IP
  multicast.
• The Mobility support
• Each BS periodically broadcasts Beacon message.
• Each MH keeps track of the recent Beacons
  received, as the location and motion information.
• BSs identified as likely handoff targets are
  asked to join the multicast group by the MH.
• Only one BS can Forward packets, while others in
  the same group Buffer the last few packets from
  HA.

12
Daedalus Model Overview
13
Implementing in NS

• Assumptions
• Full cellular mobile network (6 neighbors)
• Every BS acts as the FA(foreign agent)/ HA(home
  agent)
• Random motion of the users
• Fixed cell size

14
Implementing in NS

• Internal Functional Modules
• Base Station vs. Mobile Host

15

Implementing in NS
Our Implemented Module
Node
MHO Agent
ClassifierForwarding
Agent Protocol Entity
Routing (DSDV)
Node Entry
LLLink layer object
LL
IFQInterface queue
MAC Mac object (802.11)
MAC
Mobile Node
PHY Net interface (Wireless Physical)
PHY
CHANNEL
16
Current Status

• Implementation is completed, but our code has
  some bugs.

17
Simulation

• Preliminary step
• observed the number of lost packet and TCP
  throughput changes during handoff by Mobile IP
  using ns-2.
• It can be used to estimate the performance of
  Daedalus model comparing to the Mobile IP handoff
  scheme.
• investigated the beacon signal strengths of each
  base stations measured by the MH whenever handoff
  occurs.

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Simulation
Wired domain
W(0)
5Mb, 2ms
W(1)
BS2
HA
(3)
(1)
(2)
BS1
Wireless domain
19
Simulation
The accumulated packet losses (mean speed 10m/s)
Beacon signal strength measured at MH
20
Simulation
TCP Throughput (mean speed 10m/s)
TCP Throughput (mean speed 30m/s)
21
Simulation

• Simulation Metric
• Scalability - Number of Users, Buffer Size
• Packet Loss - Moving Speed
• Packet Throughput - Handoff Speed

22
Future Work

• Debugging our simulation code
• Simulating analyzing based on our simulation
  result
• Scalability - number of users, buffer size
• Packet Loss - moving speed
• TCP/UDP throughput
• Examining the possibility of improvement

23
References

• Hari 98 Challenges to Reliable Data Transport
  over Heterogeneous Wireless Networks, Univ. of
  Berkeley, PhD Thesis, 1998.
• Seshan96 Hari Balakrishnan, and Randy H. Katz,
  Handoffs in Cellular Wireless Networks The
  Daedulus Implementation and Experience, Kluwer
  International Journal on Wireless Communication
  Systems, 1996.
• K.Brown S. Singh, M-TCP TCP for Mobile
  Cellular Networks, ACM CCR Vol. 27(5), 1997.
• R.Ghai 94 S. Singh, An Architecture and
  communications protocol for picocellular
  networks, IEEE Personal Communications, 1994.
• Mysore98 Vaduvur Bharghavan, Performance of
  Transport Protocols over a Multicasting-based
  Architecture for Internet Host Mobility, IEEE
  International Conference on Communication(ICC98),
  Vol. 3, pp1817-1822, 1998.