This document surveys various handoff prioritization and decision schemes used in wireless cellular networks. It begins by introducing handoffs and describing the basic handoff process, including the types of handoffs and key performance metrics. It then details the phases and common schemes for horizontal handoffs between homogeneous networks. Next, it examines the phases and solutions for vertical handoffs between heterogeneous networks. It concludes by discussing the advantages and disadvantages of different handoff schemes and most recent prioritization approaches.

1. Handoff Prioritization and
Decision Schemes in Wireless
Cellular Networks: a Survey
陳恂達 Hsun-Da Chen
Institute of Communications Engineering
National Chung Cheng University
Author:
Aggeliki Sgora
Dimitrios D. Vergados
IEEE COMMUNICATIONS & TUTORIALS, VOL. 11, NO. 4, FOURTH QUARTER 2009

2. Outline
 Introduction
 Handoff Process
 Horizontal Handoff Process
 Vertical Handoff Process
 Conclusion
 References

3. Introduction
 Cellular Networks
 Handoff
 Horizontal Handoff
 Vertical Handoff

4. Introduction

5. Handoff Process
 Types of Handoff
 Performance Metrics of Handoff Schemes

6. Handoff Process
 Types of Handoff

7. Handoff Process
 Types of Handoff

8. Handoff Process
 Performance Metrics of Handoff Schemes
New (or originating) call blocking probability
Handoff call blocking
Handoff probability
Call dropping
Delay
Channel utilization efficiency

9. Horizontal Handoff Process
 Handoff Phases
Measurement
Initiation
Decision
 Mobile-Controlled Handoff (MCHO)
 Network-Controlled Handoff (NCHO)
 Mobile-Assisted Handoff (MAHO)
Execution

10. Horizontal Handoff Process
 Handoff Schemes

11. Horizontal Handoff Process
 Handoff Schemes

12. Horizontal Handoff Process
 Handoff Schemes
Non-Prioritized Scheme (NPS)
Prioritization Schemes
 Channel Reservation Schemes (CRS)
 Handoff Queuing Schemes (HQS)
 Channel Transferred Handoff Schemes (CTS)
 SubRating Schemes (SBRS)
 Genetic Handoff Schemes (GHS)
 Hybrid Handoff Schemes (HHS)

13. Horizontal Handoff Process

14. Vertical Handoff Process
 Handoff Phases
System discovery
Handoff decision
Handoff execution

15. Vertical Handoff Process
 Handoff Schemes

16. Vertical Handoff Process
 Vertical Handoff Solutions
Network Layer Vertical Handoff Solutions
 WWAN-WLAN
 3G-WLAN
Upper Layer Vertical Handoff Solutions
 Migration Monitor Module
 Handoff-aware TCP Core Module
 Resumption Module

17. Conclusion
 Handoff schemes on homogeneous and
heterogeneous networks.
 Pros and cons of handoff schemes
 The most recent handoff prioritization

18. References
 [1] Sgora, A.; Vergados, D.D.; Communications Surveys &
Tutorials, IEEE Volume 11, Issue 4, Fourth Quarter 2009
Page(s):57 - 77