Handover mechanisms in next generation heterogeneous wireless ...

More documents

Recommendations

Info

TRUST ASSISTED HANDOVER ALGORITHM FOR RELIABLE HANDOVER when the RSS P new of the new point of attachment is larger than the P old by a hysteresis margin H. Pth � P � H (Equation 5.2) Pnew old Pold Pnew Figure 5.1 RSS-based handover decision algorithm Therefore, in the scenario of Figure 5.1, the handover occurs at time t1 if a single RSS metric is used. The handover triggering time is delayed to time t2 when a RSS hysteresis margin is added. Other handover metrics can be used as well for more complex scenarios, such as Microcell/Macrocell overlay [1]. In packet-oriented wireless networks, handover decision has to deal with more things. A variety of services being carried on IP packets may have different requirements related to QoS. The quality of the wireless channel in a handover is no longer the only concern. A number of handover metrics such as bandwidth, service type, monetary cost and so forth would have to be considered in handover decision making for wireless data services. The cost-based Multicriteria Handover Algorithms (MHOA) such as Dynamic Vertical Handover Algorithm [83] and Policy-Enabled Handover Algorithm [88] were proposed to handle multiple handover decision metrics that are required for optimising data services in heterogeneous wireless networks. The basic idea behind the MHOA is easy - 84 -
TRUST ASSISTED HANDOVER ALGORITHM FOR RELIABLE HANDOVER to understand. The mobile user uses multiple handover metrics as input, and makes decision based on the comparison of the costs of a set of candidate networks using a cost function model. The weight for each metric is determined based on the contribution of that metric to network selection. Basically, the MHOA can be generalised as follows: �m � � C n � w i � N i where ( � w i � 1 ) (Equation 5.3) i where C n means the cost of the nth candidate network. i m and w i represent the ith handover metric and its weight in all handover decision metrics. The parameter i m is normalised to �mi� N using a normalisation function, which ensures the sum of different metrics is of the same magnitude or order. Wang et al. first presented the concept of policy-enabled handover in [88], in which three handover metrics: network bandwidth ( n B ), power consumption ( n P ) and monetary cost ( n C ) were considered in handover decision making for the overlapped heterogeneous networks. These parameters are normalised using logarithm so that all of the parameters can be included in the same cost function f n , which is the normalised cost. Mobile user can change the handover policies by adjusting the weight of each parameter in the cost function. However, Wang’s policy-enabled cost function had three metrics, which are limited and insufficient for a comprehensive evaluation of candidate networks. In the Dynamic Vertical Handover Algorithm with Network Elimination [83], McNair et al. developed a two-dimensional handover cost function that took into account new handover metrics including service type, network conditions, system performance, user preference and so on. In one dimension, the function uses the different types of services requested by the user. In another dimension, it represents the cost to the network according to specific handover parameters [83]. The general form of the cost function is represented as: n �� ws, i � ps i (Equation 5.4) n f � , s i - 85 -
Page 1 and 2:
Handover Mechanisms in Next Generat
Page 3 and 4:
ACKNOWLEDGMENT First of all, I woul
Page 5 and 6:
TABLE OF CONTENTS 4.4.2 Power Save
Page 7 and 8:
LIST OF FIGURES LIST OF FIGURES Fig
Page 9 and 10:
LIST OF FIGURES Figure 7.2 A generi
Page 11 and 12:
ABSTRACT New access technologies su
Page 13 and 14:
Chapter 1 INTRODUCTION New access t
Page 15 and 16:
INTRODUCTION becomes available. Han
Page 17 and 18:
INTRODUCTION The above multipliciti
Page 19 and 20:
INTRODUCTION network trust pattern
Page 21 and 22:
INTRODUCTION 1.3 Related Publicatio
Page 23 and 24:
INTRODUCTION TECHNICAL REPORTS XIII
Page 25 and 26:
HANDOVER MANAGEMENT horizontally. H
Page 27 and 28:
HANDOVER MANAGEMENT The objective o
Page 29 and 30:
HANDOVER MANAGEMENT air interface,
Page 31 and 32:
HANDOVER MANAGEMENT proposed archit
Page 33 and 34:
HANDOVER MANAGEMENT Access point (A
Page 35 and 36:
HANDOVER MANAGEMENT users. Moreover
Page 37 and 38:
HANDOVER MANAGEMENT For IEEE 802.11
Page 39 and 40:
HANDOVER MANAGEMENT The two schemes
Page 41 and 42:
HANDOVER MANAGEMENT When a MH is mo
Page 43 and 44:
3.1 Introduction Chapter 3 HANDOVER
Page 45 and 46: SECURITY FOR HANDOVER ACROSS HETERO
Page 69 and 70: DYNAMIC NEIGHBOUR TRUST INFORMATION
Page 93 and 94: Chapter 5 TRUST ASSISTED HANDOVER A
Page 95: TRUST ASSISTED HANDOVER ALGORITHM F
Page 99 and 100: TRUST ASSISTED HANDOVER ALGORITHM F
Page 123 and 124: Chapter 6 PROXY BASED AUTHENTICATIO
Page 125 and 126: PROXY BASED AUTHENTICATION LOCALISA
Page 147 and 148:
MULTI-INTERFACE MOBILE MODEL FOR ME
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
CONCLUSIONS AND FUTURE RESEARCH WOR
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
ABBREVIATIONS 3G 3rd Generation Wir
Page 177 and 178:
ABBREVIATIONS LS Location Server MH
Page 179 and 180:
ABBREVIATIONS THOA Trust Assisted H
Page 181 and 182:
REFERENCES [12] C. Politis, T. Oda,
Page 183 and 184:
REFERENCES [37] Wi-Fi Alliance, "Wi
Page 185 and 186:
REFERENCES presented at IEEE Intern
Page 187 and 188:
REFERENCES [90] R. Verdone and A. Z
Page 189:
REFERENCES [116] K. E. Malki and H.
show all

Handover mechanisms in next generation heterogeneous wireless ...

Create successful ePaper yourself

Delete template?

Save as template?