Related to wireless technology , hand-off techniques, Based on IEEE Research papers

1. GTU PG SCHOOL
BISAG Gandhinagar
Handoff Scheme for High-speed
Mobile Internet
Services
-Vrajesh Parikh
WIMC
1st
SEM

2. Issues in Mobility with High
Speed Internet
●
Reliable user authentication and mobility
●
Network security at speed
●
Device flexibility
●
Delay time in hand off

3. Types of Handoff
●
Vertical Handoff :- Changing the technology to
access internet
●
Horizontal Handoff:-changing access point for
connectivity

4. What we want during mobility?
• We want our applications not to be disturbed from
mobility
• We want to continue to talk with our cell-phone
when we change base-stations
• We want to continue to run telnet when we change
access points in a Wireless LAN.

5. Problems With Hetrogenous
Networks
-Problems with various protocols in heterogeneous
networks:-
• MIP network layer, SCTP at transport layer, SIP in
application layer.
• MIP is the best solution to sort the matter but still it
suffers long handoff latency.

6. Changes needed for Heterogeneous
Networks
rate adaptation, congestion control, mobility support,
and coding, In particular, they present adaptiveness
in layers 2 (link), 4 (transport), and 7(application) to
satisfy the demand of heterogeneity and high speed
multimedia applications in 4G wireless data
networks

7. Fast handoff scheme in public
WLAN systems
• Reduce the handoff latency caused by authentication
procedures
• MH performs authentication procedures not only for
the current AP but also for neighboring APs.
(Problem is to select neighboring nodes and
authentication).
• The simplest method is to select all of the APs
adjacent to the current AP.
• And this is done based on the centralized AP
configuration.

8. Approach 1 -Proposed Handoff
Scheme
• The objective of the proposed handoff scheme is to
reduce the handoff latency caused by authentication
procedures at the new AP.
• MH performs authentication procedures not only for
the current AP but also for neighbouring APs, when
initial registration is performed. The key issue in this
scheme is how to select the neighbouring APs to be
authenticated in advance.

9. Prediction Based Proposal
• Network specific prediction scheme
– handoff prediction algorithms
– Previous mobility patterns using pervious patterns
– Most MHs in public WLAN systems are visiting or
temporary hosts without any regular mobility patterns.
• Mobile-specific prediction scheme, we utilised a network-
specific prediction scheme. In our prediction scheme, the
handoff probability between APs is estimated using the
previous handoff ratio and residence time collected and
calculated by the central system.

10. FHR(Frequency handoff region)
• Record events in event log data base
•Calculate Hand off ratio
•H(i, j) and N(i, j) denote the unit handoff
ratio andthe number of handoff events from
AP(i) to AP(j).
Let Rk(i, j) be the residence time in the kth
handoff event from AP(i) to AP(j)

11. FHR(Frequency handoff region)
cont…
•where Tout(k) and Tin(k) are in-time and out-time of kth handoff event.
•For the FHR selection algorithm, we should draw a weighted bi-directional graph on
AP placements. The weight values between APs are determined by the handoff ratio.
•the weight value is reversely proportional
to the handoff ratio.
In addition, if two APs are not adjacent,
the weight value is infinite.

12. Approach 2-Creating HMSMN

13. Operation of HMSMN
• Network Detection
• Handoff Decision
• Handoff Initiation
• Handoff Execution

14. Detailed Description
• Network Detection -
– Detect multiple network technologies
– Obtain information about neighboring wireless technologies
– currently serving technology
• Handoff Decision-
-when the MN should handoff
-handoff decision metrics such as RSS, end-user preference, QoS
requirement, service type, communication cost,
• Handoff Initiation-
• -Estimates the right time to start the MIP handoff operation

15. Detailed Description
-The measured RSS of the currently serving BS (AP) drops below a
predefined threshold, the handoff trigger function gives a handoff
trigger with network information.
• Handoff Execution-
• -When the MN starts the MIP handoff operation, there are two
different approaches, basic and tight integration approaches, to
integrate HMSMN and MIP on whether HMSMN closely cooperates
with MIP or not.

16. HMSMN Integration with MIP
• Basic integration approach-
– HMSMN to be transparent to the MIP operation
– In this case, HMSMN initiates a vertical handoff by simply
switching the network access technology (via. network switching
function) between multiple network interfaces.
• Tight integration approach-
– In this approach, HMSMN interworks with MIP to maintain seamless
connectivity during the vertical handoff by triggering the MIP handoff operation
for the new network while maintaining the connection to the previous network.

17. HMSMN coupled architectures

18. HOW the HMSMN Works?

19. References
1. A Client-based Vertical Handoff Approach for
Seamless Mobility in Next Generation Wireless
Networks.
-Yong-Sung Kim, Dong-Hee Kwon, Young-Joo Suh
• Fast handoff scheme based on mobility prediction in
public wireless LAN systems
- S. Pack and Y. Choi

20. Queries