A PRESENTATION MASTER OF TECHNOLOGY IN ELECTRONICS ENGG.(P.T.)

Presented by:Narendra Kumar

Roll No. 1181043007Under the Guidance of

Department of Electronics Engineering, UP, India

OVERVIEW OF HANDOVER TECHNIQUES IN HETEROGENEOUS WIRELESS NETWORKS

The availability of diverse wireless access technologies such as (Wi-Fi), (WiMAX), and (UMTS) allows users to stay “always on” in fast roaming too using IEEE802.21.

Vertical handovers had made possible for user to transfer itself to other technology service without disturbances in ongoing process.

Its is known that security problems in GSM authentication when it comes to high speed moving users, because of there frequent change of cell sites.

Handover could be horizontal or vertical and per user requirement. MIH (media independent handover) though provide vertical handover but on other hand 802.11had provided us fast and secure connection oriented handover from one access point to another with in same mobility domain.

Thus feature of security and authentication is integrated with handover for user security.

MOTIVE OF THE PAPER

What are heterogeneous networks? Evolutions of Generations The Cellular GSM Transitions Overview of 4G Communications Concept of Handover /Handoff Handovers distinguished according to criteria The Vertical handover IEEE 802.21 & its phases. VHO Management procedures Requirements of Handover mechanism in heterogeneous

networks Performance evaluation (Technology ) Performance evaluation in Handover mechanisms Conclusions References

CONTENTS

An interconnection of multiple networks irrespective of topology, network architecture etc. The networks may be multiple IP networks, Cellular networks, ad hoc networks, and satellite networks with prescribed bandwidth capacity, link speeds and other parameters. Each network has respective performance metrics for describing their characteristics.

The next generation communication aims at integration of different networks. The communicating devices needs frequent mobility and communicate to each other in the different architectural and topological networks.

However, if a mobile devices moves among different types of network during communication, there is a serious problem of call drop or interrupted communication due to improper handoff It also affects it’s QoS.

HETEROGENEOUS NETWORKS

HETEROGENEOUS NETWORKS

WIMAX

WiFiShort range LAN/PAN/

WAN

Wireless Broadband

Cellular GSM 2G

Cellular 4G WIMAX

USERCellular 3G ( UMTS)

POPPING OF GENERATIONS

EVOLVING THE G’S

3G: UMTS

2.5G: GSM + GPRS

2G : GSM Core Network

GatewayMSC

VLR

HLR

MSCMobileSwitchingCenter

BSCBaseStationController

BTSBaseTransceiverStations

InternetISDN

PLMNPSTN SIM

MobileEquipment

MobileStation

Core Network

GatewayMSC

VLR

HLR

MSCMobileSwitchingCenter

GatewayGPRSSupportnode

ServingGPRSSupportnode

BSCBaseStationControllerPCU

BTSBaseTransceiverStations

SIM

MobileEquipment

InternetISDN

PLMNPSTN MobileStation

UTRANCore NetworkGatewayMSC

VLR

HLR

MSCMobileSwitchingCenter

GatewayGPRSSupportnode

ServingGPRSSupportnode

UMTSSIM

MobileEquipment

RNCRadioNetworkController

RNCRadioNetworkController

Node B

Node B

Node BNode B

InternetISDN

PLMNPSTNUserEquipment

THE CELLULAR GSM TRANSTITION

4G : Mobile Communications

THE CELLULAR GSM TRANSTITION

COMMUNICATIONFUTURE TECHNOLOGY- 5 G

CONCEPT OF HANDOVER/ HANDOFF

Movement of mobile in different regions.(near far problem)

Capacity of one BTS is almost full.(call setup/disconnection)

Umbrella approach.

HANDOVERS DISTINGUSHED ACCORDING TO CRITERIA

(A) LOCATION OF A HANDOFF FUNCTION

Network-Controlled Handoff• The network makes a handoff decision based on the measurements

of the MSs at a number of BSs.• Used in first-generation analog systems such as AMPS (Advanced

Mobile Phone System), TACS(Total Access Communication System), and NMT (Nordic Mobile Telephone). HO time 100-200ms

Mobile-Assisted Handoff• The MS makes measurements and the network makes the decision.• In circuit-switched GSM ,BSC is in charge of the radio interface

management i.e. allocation and release of radio channels and handoff management. HO time-1s.

Mobile-Controlled Handoff• In mobile-controlled handoff, each MS is completely in control of the

handoff process.• This type of handoff has a short reaction time (in the order of 0.1

second).• MS measures the signal strengths from surrounding BSs and

interference levels on all channels.• A handoff can be initiated if the signal strength of the serving BS is

lower than that of another BS by a certain threshold.

HANDOVERS DISTINGUSHED ACCORDING TO CRITERIA…..

(B) NETWORK ELEMENT INVOLVED

Intra-cell, Inter-cell and Inter-network.

(C) NUMBER OF ACTIVE CONNECTIONS

Hard Handover (Break “OLD” Before “NEW” Make)• Only one connection exists in a given time point• Used in FDMA and TDMA systems to minimize adj. channel interference.• Cheaper, easier to implement. Simpler hardware of MT required.

Soft Handover (Make “NEW” Before “OLD” Break)• Several connections with the same information are maintained simultaneously at a given time point.• Used in UMTS to improve the signal quality.• Uplink and downlink signals may be combined for better signal• A mobile in UMTS may spend a large part of the connection time.• Better connection reliability- MORE SEALMLESS HANDOVER.• Used in CDMA technology.• Technical Implementation expensive & complex.

HANDOVERS DISTINGUSHED ACCORDING TO CRITERIA…..

Softer Handover • One BTS/Node receives 2 user signals from 2 adjacent sectors it serves.• One BTS/Node receives 2 separated signals through multi-path propagation or reflections from buildings or natural barriers.

HANDOVERS DISTINGUSHED ACCORDING TO CRITERIA…..

Mechanism of Hard Handover

HANDOVERS DISTINGUSHED ACCORDING TO CRITERIA…..

Mechanism of Soft Handover

HANDOVERS DISTINGUSHED ACCORDING TO CRITERIA…..

Homogeneous (Horizontal) Handovers MT changes point of connection with same type of network Localized Mobility E.g. from a cell to another in GSM E.g. from an access point to another in WiFi

Reasons for handover- Worse signal quality or loss of signal, Traffic load balancing, Cost Limited opportunities

HANDOVERS DISTINGUSHED ACCORDING TO CRITERIA…..

Heterogeneous (Vertical) Handovers MT changes point of connection across

different types of network . Global Mobility automatic fall over from one technology to

another in order to maintain communication. More opportunities

IEEE 802.21 is primarily for Vertical Handovers ….can also be used for Homogeneous Handovers

VERTICAL HANDOVER PHASES Here handover have 3 phases:

Initiation Decision Execution

Media independent handover (IEEE 802.21) provide seamless mobility among different networks.

Initiation Network discovery Network selection Handover negotiation

Decision handover algorithm(MIHF)

Execution Mobility management Handover management

VERTICAL HANDOVER PHASES…

V.H.O MANAGEMENT PROCEDURE

executing• Leaving one network and entering to

other is finalisied . Mobility management and handover management is key feature.

• Latencies and packet loss is checked after handover is complete.

Decision

• Decision are taken like when and where to trigger handover.

• Various parameters are kept into consideration for best network for user.including the type of the application (e.g., conversational, streaming), minimum bandwidth and delay required by the application, access cost; transmit power, and the user’s preferences.

• MT are re-routed from the existing network to the new in seamless way.

• This phase also includes the authentication, authorization, and transfer of a user’s context information.

collecting• Information collected from diverse source

like network properties, access point, mobile devices, and user preferences.

PERFORMANCE EVALUATION (TECHNOLOGY) IN HETEROGENEOUS NETWORKS

UMTS takes average of 29.6ms to deliver one packet, WiMAX gives 0.81ms and WiFi gives 0.23ms of latencies respectively

Abbreviation

Ref# Some Available Handoff Mechanisms

UARTVHO 12

Use of Adaptive Resonance Theory for Vertical Handoff Decision in heterogeneous Wireless Environment

VHDAHWN 16 A Vertical Handoff Decision Algorithm for Heterogeneous Wireless Networks

TAHDM 11Towards Autonomic Handover Decision Management in 4G Networks

EDHMHN 13 Efficient decision handoff mechanism for heterogeneous network

PEHHWN 8Policy-Enabled Handoffs across Heterogeneous Wireless Networks

VHDAPOP 10

Vertical Handoff Decision Algorithms for Providing Optimized Performance in heterogeneous Wireless Networks

ADDMVHO 9A Dynamic Decision Model for Vertical Handoffs across Heterogeneous Wireless Networks

PERFORMANCE EVALUATION (H.O. MECHANISMS) IN HETEROGENEOUS NETWORKS

REQUIREMENT OF H.O. MECHANISMS IN HETEROGENEOUS NETWORKS

DYNAMIC REQUIREMENTS NON-DYNAMIC REQUIREMENTS

DYNAMIC REQUIREMENTS INCLUDE RSS, VELOCITY THROUGHPUT USER PREFERENCES AS PARAMETERS.

NON-DYNAMIC REQUIREMENTS INCLUDE NETWORK COST, POWER CONSUMPTION, NETWORK SECURITY AND BANDWIDTH AS PARAMETERS.

REQUIREMENTS OF HANDOVER MECHANISMS OUTLINED ARE AS BELOW, HOWEVER, IT IS BEING STATED THE IMPORTANT PARAMETERS/METRICS AS REQUIREMENTS BUT OTHER PARAMETERS SUCH AS NETWORK CONDITIONS, NETWORK CAPABILITY AND BIT ERROR RATE CAN ALSO BE CONSIDERED DURING VERTICAL HANDOFF. A GOOD HANDOFF MECHANISM DECISION MODEL SHOULD HAVE BOTH DYNAMIC AND NON-DYNAMIC METRICS. HOWEVER, IT IS IMPORTANT TO CONSIDER MAXIMUM NUMBER OF STATIC AND DYNAMIC REQUIREMENTS DURING VHO BUT IT IS DIFFICULT TO INCLUDE ALL THE METRICS IN IN A SINGLE DECISION MODEL DUE TO COMPLEXITY OF ALGORITHMS AND CONFLICTING ISSUES OF MULTIPLE METRICS

REQUIREMENT OF H.O. MECHANISMS IN HETEROGENEOUS NETWORKS

S.N

REQUIREMENT PURPOSE IN HANDOVER MECHANISMS

1 BANDWIDTH Higher offered bandwidth ensures lower call dropping and call blocking probabilities; hence higher throughput.

2 H.O LATENCY

Delay in process of handover of calls between two. It is minimized by suitable decision models by a handoff latency factor.

3 POWER CONSUMPTION

During handoff, frequent interface activation can cause considerable battery drainage. Power saving is important factor in h.o mechanism

4 NETWORK COST

The cost is to be minimized during VHO in wireless networks. The new call arrival rates and handoff call arrival rates can be analyzed using cost function

5 USER PREFERENCES

The user preferences could be preferred networks, user application requirements (real time, non-real time), service types (Voice, data, video), Quality of service (It is a set of technologies for managing network traffic in a cost effective manner to enhance user experiences for wireless environments) etc.

6 NETWORK THROUGHPUT

It is average data rate of successful data or message delivery overa specific communications link.It is measured in bits per second (bps).Maximum network throughput equals the TCP window size divided by the round-trip time of communications data packets.

PERFORMANCE EVALUATION(HANDOVER MECHANISMS)

7

NETWORK LOAD BALANCING

To provide a high quality communication service for mobile subscribers and to enhance a high traffic-carrying capacity when there are variations in traffic to balance the network load & to avoid deterioration in quality of services.

8 NETWORK SECURITY

To prevent and monitor unauthorized access, misuse, modification, and network-accessible resourcesto attain the highest levels of integrity, authentication, and confidentiality, network security features should be embedded in the handoff policies.

9

RECEIVED SIGNAL STRENGTH (RSS)

 RSS is the performance of signal strength between a mobile node (MN) and access point (AP),the wireless signal strength in each direction determines the total amount of network bandwidth available along that connection. It depicts the power present in a received signal.A signal must be strong enough between base station and mobile unit to maintain signal quality at receiver. The RSS should not be below a certain threshold in a network during handoff. VHO includes three sequential steps as discussed earlier in this paper, namely handoff initiation, handoff decision and handoff execution. Handoff initiation is concerned with measurement of RSS

10 VELOCITY

 Velocity of the host should also be considered during handoff decision. Because of the overlaid architecture of heterogeneous networks, handing off to an embedded network, having small cell area, when travelling at high speeds is discouraged since a handoff back to the original network would occur very shortly afterwards

PERFORMANCE EVALUATION(HANDOVER MECHANISMS)

SOME HANDOVER MECHANISMSREFERENCE # 12 14 11 13 8 10 9

S.N REQUIREMENT

UARTVHO

VHDAHWN TAHDM EDHM

HNPEHHWN

VHDAPOP

ADDMVHO

1 BANDWIDTH Y Y Y Y Y Y Y2 H.O LATENCY Y       Y    

3POWER CONSUMPTION     Y Y Y Y Y

4 NETWORK COST Y Y Y   Y Y Y

5USER PREFERENCES Y Y Y Y   Y  

6NETWORK THROUGHPUT Y Y Y Y      

7NETWORK LOAD BALANCING Y Y   Y Y Y  

8NETWORK SECURITY Y            

9

RECEIVED SIGNAL STRENGTH (RSS)

  Y Y Y     Y

10 VELOCITY     Y Y     Y

The decision mechanism of VHO can become more fruitful, if the number of parameters is more during decision making . The success of VHO mechanism depends upon the decision model based on requirements/ metrics. An efficient decision mechanism can not only enhance the system capacity but also improve the quality of services for a user.

The 4G wireless networks create new handover challenges due to multiple requirements for vertical handoff. The requirements of proposed VHO include high bandwidth, low handoff latency, lower power consumption, minimum network cost, balanced network load, network security, user preferences, throughput and RSS of a switching network.

Establishing the VHO requirements is a critical milestone in the development of vertical handoff mechanism for 4G.

The evaluation indicate the need to have a VHO mechanism for 4G wireless networks that has the ability to satisfy maximum number of requirements.

However, it is difficult to consider all the parameters during designing the decision model for VHO but if we consider more parameters, the outcome of the decision mechanism would definitely improve.

CONCLUSION

1. McNair, J. ; Fang Zhu (2004), “Vertical handoffs in fourth-generation multinetwork environments”in IEEE pp8-15

2. Mandeep Kaur Gondara and Dr. Sanjay Kadam (2011) “ Requirements of vertical Handoff Mechanism in 4G wireless Networks” - International Journal of Wireless & Mobile Networks (IJWMN) Vol. 3, No. 2, April 2011 pp18-27.

3. A Handout on GSM Basics,Version 1 Revision 0, published by BRBRAITT, BSNL Jabalpur, Issued in March –2007

4. Avi Freedman, Zion Hadad (sep 2002 ), “ Handoff Schemes Overview and Guidelines for Handoff Procedures in 802.16” , in IEEE C802.16sgm-02/24

5. S.K. Shukla, A.K. Vatsa, Pooja Dubey (2012), “Fast & Reactive Handoff Over Hetrogeneous Networks”in IJCSMS-International Journal Of Computer Science and Management Studies, Vol-12 Issue-02 April 2012 pp7-12

6. 4G Americas, (October 2013) “ Self Optimizing Networks-benefits of SON in LTE” pp12,13-507. Zahid Ghadialy (2005), “Handover principle and concepts “ from google search8. H.J. Wang, R. H. Katz & J. Giese,(1999) “Policy-Enabled Handoffs across Heterogeneous Wireless

Networks”, In proc. of ACM WMCSA.9. Pramod Goyal & S. K. Saxena,(2008)“A Dynamic Decision Model for Vertical Handoffsacross

Heterogeneous Wireless Networks”,677 ? 2008 WASET.ORG, World Academy of Science, Engineering and Technology,Issue 41,pp 676-682.

10.SuKyoung Lee , Kotikalapudi Sriram, Kyungsoo Kim, Yoon Hyuk Kim & Nada Golmie,January (2009)“Vertical Handoff Decision Algorithms for Providing Optimized Performance in Heterogeneous Wireless Networks”,IEEE transactions on Vehicular Technology.

11.Joon-Myung Kang, Hong-Taek Ju2 & James Won-Ki Hong,(2006) “Towards Autonomic Handover Decision Management in 4G Networks”, In Proceedings of MMNS'2006,pp145-157.

12.Mrs. Chandralekha & Dr. Prafulla Kumar Behera,November (2009) “Use of Adaptive Resonance Theory for Vertical Handoff Decision in Heterogeneous Wireless Environment”, International Journal of Recent Trends in Engineering, Vol. 2, No. 3.

13.A. Dvir, R. Giladi, I. Kitroser & M. Segal,February (2010) “Efficient decision handoff mechanism for heterogeneous network”, International journal of Wireless and Mobile networks,Vol. 2, No. 1.

14.E.Stevens-Navarro,Vincent W.S.Wong & Yuxia Lin,(2007) "A Vertical Handoff Decision Algorithm for Heterogeneous Wireless Networks",In Proc. of Wireless Communications and Networking Conference, IEEE ; doi:10.1109/WCNC. 2007.590

REFERENCES

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Narendra Kumar+91- 9450000911