Mobility Management Techniques To Improve QoS In Mobile Networks Using Intelleigent Agent Decision Making Protocol by ijcsis


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									                                                       (IJCSIS) International Journal of Computer Science and Information Security,
                                                       Vol. 9, No. 1, January 2011

  Mobility Management Techniques To Improve QoS
    In Mobile Networks Using Intelleigent Agent
             Decision Making Protocol
                       Selvan.C                                                      Dr. R.Shanmugalakshmi
    Department of Computer Science and Engineering                         Department of Computer Science and Engineering
          Government College of Technology,                                      Government College of Technology,
            Coimbatore, Tamil Nadu, India                                          Coimbatore, Tamil Nadu, India

                                                                                              I.    INTRODUCTION
              Abstract—Mobility Management (MM) is one of
                                                                                Mobility Management (MM) [3] is one of the major
the major issues of Mobile networks that should be taken into          functions of a GSM or other Network. The aims of MM are to
account for providing Quality of Service (QoS) and to meet the         track where the subscribers are so that calls can be sent to
                                                                       them, and to record the subscriber services.
subscribers   demand   (satisfaction).   Mobility   management
                                                                               Mobile networks to provide quality of service (QoS) is
techniques are divided into two types (i) Location Management          challenging for the service providers. By introducing Intelligent
(LM) and (ii) Handoff Management (HM). The LM is used for              Agent in MM it is possible to meet the QoS. The MM is
tracking where the subscribers are locate, and based on that
                                                                       divided into two major divisions as Location Management
                                                                       (LM) and Handoff Management (HM). The various MM
permitting calls, Short Message Service (SMS) and other mobile         techniques used in mobile networks are shown in Figure 1.
phone services are delivered to them with the assistance of
Intelligent Agent Decision Making Protocol (IADMP). The
Redundant Update Remove Algorithm (RURA) which is used for
reducing the updation between BSC and MSC. Enhanced
Temporal Updation (ETU) reduces the location updates between
Mobile Node (MN) and MSC using IADMP. To provide
ubiquitous communication for subscribers without any break in
the communication, HM protocols play main role in Mobile
Networks. In HM process there are four protocols, (i) Double
Threshold Protocol (DTP) (ii) Better Base Station Selection
Protocol (BBSSP) using Relative Signal Strength (RSS) (iii)
IADMP and (iv) Hybrid Decision Making Protocol (HDMP) are
used. The Performances of these protocols are analysed. The
HDMP and ETU provide QoS in Mobile Networks.
                                                                               Figure 1. Overview of Mobility Management Techniques
  Keywords-component;      Location   Management;Handoff
Mangement; Intelligent Agent; Enhanced Temporal Updation;                       In Location Management [5], the ability to manage
RUR Algorithm; IADMP                                                   information about the current location of mobile nodes based
                                                                       on their last update is a significant issue. That enables the
                                                                       network to discover the current attachment point of the mobile
                                                                       user for call delivery. Location Management is further divided
                                                                       into (1) Paging and (2) Call delivery and (3) Location updation.

                                                                                                    ISSN 1947-5500
                                                           (IJCSIS) International Journal of Computer Science and Information Security,
                                                           Vol. 9, No. 1, January 2011

    An important issue in the design of Mobile network is how             B. Paging
to manage the locations of mobile nodes and giving continuous                Paging is one of the fundamental mobility management
connections to the subscribers wherever they go. The Mobile               procedures of a GSM network and also other cellular networks.
networks encompass the mobility management to provide                     MSC will request the BSC to scan all the active nodes under its
ubiquitous and continuous communication to the subscribers,               coverage [1]. The BSC will send all the data to MSC after
billing for the usage and further use.                                    scanning all the nodes.
       An important issue in the design of Mobile network is                  The Visitor Location Register (VLR) which normally
how to manage the locations of mobile nodes and giving                    knows the current location of the subscriber to the level of a
continuous connections to the subscribers wherever they go.               location area. The VLR also knows which BSC controls cells
The Mobile networks encompass the mobility management to                  in that location area. The VLR sends a paging request message
provide ubiquitous and continuous communication to the                    to each of the relevant BSC. The BSC then send a paging
subscribers, billing for the usage and further use.                       request to every single cell within the location area. This
                                                                          paging request is broadcast on the cell broadcast channel to
              II.      LOCATION MANAGEMENT                                which the mobile is listening.
    The Location Management (LM) maintains the location of
the Mobile Nodes to provide services. A micro cell [15]                   C. Call Delivery
maximum coverage area is called location of a mobile node. A                  When a mobile node tries to communicate with other
group of locations is called a location area. The LM is divided           mobile node, the call reaches MSC first through BSC, after that
into three functions, updation follows paging and call delivery.          only the connection will be established to concern mobile node
The updating function makes the Mobile Node to update its                 through BSC. Whenever the call comes from same or other
place to the corresponding BSC. Paging operation is performed             network, the connection is established based on the Temporary
by the BSC to track all the locations of the mobile nodes at a            Mobile Subscriber Identity (TMSI). TMSI is the identity most
time and periodically.                                                    commonly sent between the mobile node and the network. An
                                                                          important use of the TMSI is in paging of the mobile.
A. Analysis of Location Area
                                                                          D. Updation
    A GSM (Global System for Mobile Communication)                            The Location update procedure allows a mobile node to
network is a radio network of individual cells, called as base            inform its active state to MSC through BSC. The updation is
stations. Each base station covers a small geographical area              divided into three (1) Spatial updation (2) Temporal updation
which is division of a uniquely identified location area. By              and (3) Enhanced Temporal Updation. This updation will be
integrating the coverage of each of these base stations, a                stored into the MSC through BSC. This updation process will
cellular network provides radio coverage over a much wider                take place periodically. The mobile node sends a message
area. A group of base stations is named as location area.                 (location update request) to the network about its current
                                                                            1) Spatial Updation:
                                                                              The Spatial updation allows a Mobile Node (MN) to inform
                                                                          to the cellular network whenever it moves from one location
                                                                          area to the next. The mobile nodes should send updation to
                                                                          base station for receiving calls if any comes. When the mobile
                                                                          node does not send the updation it might be considered as a not
                                                                          reachable MN or switched off MN.
                    Figure 2. Geographical location area
                                                                            2) Temporal Updation:
                                                                              The Temporal updation is performed based on the periodic
                                                                          time. The setting of interval time will be controlled by MSC. In
                                                                          the existing system the MN will inform the location of its exact
                                                                          place periodically. The location of the mobile node will be
                                                                          carried out to MSC through BSC.
                                                                              Figure 4 gives the detailed operation of the existing update
                                                                          of the temporal updation. In this Figure 4, MN sends LU
                                                                          (Location Update) signal to BSC, the BSC forwards signal to
                    Figure 3. Geometrical location area                   MSC for updation. At the same time BSC sends
                                                                          Acknowledgement (ACK) to MN. After receiving signal from
    Figure 2, shows the geographical representation of location           BSC, the MSC sends Location Acknowledgement (LA) to
area and its divisions and the geometrical representation of              BSC. At last the BSC forwards the LA signal to MN.            is
location area were shown in Figure 3.                                     time taken for single updation between MN and MSC. The
                                                                          operations are performed regularly by the mobile network. In
                                                                          this method, the update function takes place whenever the MN

                                                                                                      ISSN 1947-5500
                                                               (IJCSIS) International Journal of Computer Science and Information Security,
                                                               Vol. 9, No. 1, January 2011

sends update signal. Even though the mobile node is in the                    = t0+ t1 + t2 , Tt - Total time for reaching MSC,        - Time
same location cell, the BSC forwards the update signal to MSC                 taken for location updation with ACK, The update signal is
when it uses temporal updation. To solve this issue, the RURA                 sent to BSC from MN in t1 time. The update signal is sent from
(Redundant Update Remove Algorithm) is used. This                             BSC to MSC in t2 time. When the redundant signal comes
algorithm removes the unnecessary updation between BSC and                    from the Mobile node, the BSC will not respond to MSC and
MSC.                                                                          Mobile node. But it will update its buffer with time stamp.
                                                                                 The TABLE I. shows the movement records [7] of a single
                                                                              mobile node, for three hours using the temporal updation. The
                                                                              updation takes place every 10 minutes once. It updated 21
                                                                              times for three hours. The Table II shows the movement
                                                                              records of a single mobile node using RURA; it needs only six
                                                                              updates for three hours. The updation takes place every 10
                                                                              minutes once.

                                                                                  TABLE I.      UPDATING RECORDS USING TEMPORAL UPDATION

             Figure 4. Existing System - Location Update

    a) RURA (Redundant Update Remove Algorithm)
   RURA removes the redundant update when the mobile
node updates the same location. Figure 5, describes the
functions of the mobile network using RURA. The BSC
encompasses the RURA which never allow the same update to
MSC. The Location Updation (LU) signal from MN and BSC,
ACK signal from MSC and BSC are shown in figure 5.

                                                                                        TABLE II.      UPDATING RECORDS USING RURA

         Figure 5. Functions of Updating Location using RURA

   Whenever the location update takes place, the BSC will
check the location symbol with existing buffer value, suppose
the transmitted symbol not equal to existing symbol, it will
update into the MSC otherwise it will not inform to the MSC.

                 Figure 6. Timing diagram for RURA

   In figure 6 t0 – Starting time for updation in Mobile node, t1
– Time taken to reach BSC, t2 – Time taken to reach MSC, Tt

                                                                                                          ISSN 1947-5500
                                                       (IJCSIS) International Journal of Computer Science and Information Security,
                                                       Vol. 9, No. 1, January 2011

                                                                           TABLE III.      COMPARISON OF DIFFERENT UPDATION TECHNIQUES

                                                                           Figure 8 shows the graphical representation of packet
                                                                        updation using different updation techniques.

                   Figure 7. RURA Algorithms
                                                                                        Figure 8. Mobile Nodes Vs Packet Update
    Figure 7 explains the RURA algorithm. The MN signal is
checked with existing BSC buffer, whether equal to or not. If               TABLE IV shows the Comparison of delay in different
the MSC signal is not equal to BSC buffer value, the MN                 updation techniques. Here the delay means, the time taken by
signal will be stored into the BSC buffer as well as the MN             the mobile node to receive the acknowledgement signal from
signal will be forwarded to the MSC.                                    MSC. The delay is reduced in ETU compared to other
   The proposed RUR Algorithm reduces the updates only                  techniques.
between BSC and MSC. In order to reduce the updates in BSC
and also in MSC, a new technique known as Enhanced                      TABLE IV.       COMPARISON    OF   DELAY     IN   DIFFERENT     UPDATION
Temporal Updation (ETU) is introduced.                                  TECHNIQUES

  3) Enhanced Temporal Updation:
    The Enhanced Temporal Updation (ETU) is a temporal
updation technique which is performed based on (1) RURA
and (2) IADMP (Intelligent Agent Decision Making Protocol).
The RURA removes the redundant location updates. The MSC
encompasses IA which has an IADMP (Intelligent Agent
Decision Making Protocol). This Protocol predicts the updation
of the MN. When the MN updation has to take place, when the
MN updation has not to take place and how long the updates              Figure 9, a graph plotted for Mobile Nodes Vs Delay. The
are needed? And how long no need? For these questions are               Enhanced Temporal updation technique compared with other
answerable based on the movement history and call history               techniques, the ETU takes less updation delay. In ETU the
[16] of MN. The IA analyse the each MN movement history                 packet updation and delay are reduced compared to other
and call history using data mining [[6], [2], [11]] process.            techniques. Hence ETU technique provides QoS to Mobile
IADMA sends the signal to the MSC to send update-lock-temp              networks.
signal to Mobile node. The MSC temporarily stops the Mobile
node updates using update-lock-temp signal. This signal will be
sent from MSC to Mobile node through BSC. This update-
lock-temp signal will be released automatically after the fixed
time. Whenever the update-lock-temp signal is released by the
mobile node, it will be informed to MSC. This information also
will be analysed by IADMP for future use. Hence the
Combination of IADM Protocol and RUR Algorithm is known
as Enhanced Temporal Updation (ETU).
    The TABLE III shows the comparison of packet updation
using different updation techniques. The number of updation is
reduced in ETU compared to spatial updation and temporal                                   Figure 9. Mobile Nodes Vs Delay

                                                                                                      ISSN 1947-5500
                                                          (IJCSIS) International Journal of Computer Science and Information Security,
                                                          Vol. 9, No. 1, January 2011

              III.   HANDOFF MANAGEMENT                                    round-trip time. The speed estimation unit measures the speed
    In Cellular Telecommunications, the term handoff refers to             of the mobile node. Based on the speed of the Mobile node
the process of transferring an ongoing call or data session from           and signal strength, the handoff is initiated in prior to support
one channel to the core network. In Cellular communication                 seamless communication. When the Mobile nodes move close
handoff is the key matter to provide continuous service to the             to next base station, the base station informs to BSC about its
mobile nodes without any break. A single cell [8] does not                 very low signal. Then BSC takes decision and request the MSC
cover the whole service area. There are two basic reasons for a            for handoff. Many cases this kind of handoff initiations are
handoff such as (1) The mobile node moves out of the range of              failed. For example, the person carrying mobile node may go
cell (2) The received signal level decreases continuously until it         very close to Base station but he may change his direction at
fall below the minimal requirement for communication                       last minute. In this situation the handoff process may be
[12].Hence Horizontal Handoff refers the same network                      wasted. In order to avoid this IADM Protocol is introduced to
handoff. The vertical Handoff refers the different network                 analyse the movement history of the Mobile node. At last
Handoff.                                                                   IADMP will suggest whether handoff initiation should be done
                                                                           or not. Better base station is identified by BBSSP.
A. Analysis of Handoff Techniques
                                                                           B. IADMP (Intelligent Agent Decision Making Protocol)
    The Efficiency of the system handoffs [4] depends on the
five characteristics (1) Minimum handoff latency (2) Low                       The Intelligent Agent Decision Making protocol is used to
packet loss (3) Limited handoff failure (4) Intelligent Agent              provide QoS in mobile networks. The IADMP does the
success rate high (5) Better Base Station Selection.                       following works i) Predicts the updation of the mobile node
                                                                           based on the mobile nodes service history and ii) Take the
    An analytical model has been previously developed for                  decision which base station is better when the handoff take
evaluating the performance of handoff algorithms based on                  place based on the mobile nodes handoff history. In this work
Relative Signal Strength (RSS) [[4], [10]] measurements, i.e.,             Apriori Algorithm is used for mining frequent itemsets.
the difference of signal strength from two Base stations,
Absolute Signal Strength (ASS) which is the averaged value of
                                                                           TABLE V.     MOVEMENT HISTORY OF MOBILE NODE
the received signal level from current serving Base station
measured by the mobile unit. The Measurement reports [8]
including the quality of current link are sent to BSC by the
Mobile node about every half second. The BSC receive the
Mobile node signal and take decision, then it sends Handoff-
request signal to MSC. Then MSC will send the signal to the
BSC that activate the next Base station. Then the mobile node
is taken over by the activated base station. The acknowledged
signal is sent by mobile node to BSC and then BSC to MSC.

                                                                               The table V refers the data records of mobile node
                                                                           movements based on location history. In the initial process it
                                                                           collects all the details from MSC. The IADMP does the data
                                                                           mining process to find the frequent data sets using Apriori
                                                                           algorithm. The Apriori algorithm, the first step, it scans all of
                                                                           the transactions in order to count the number of occurrences of
                                                                           each item. Here number 2 is taken as a minimum support
                                                                           count. The algorithm counts the each candidate frequent
                                                                           occurrences, the frequency of the occurrences less than 2
                                                                           means it will not consider for future use, otherwise it will be
                                                                           taken into account to take decision. At last the high frequently
                                                                           occurring pattern is retrieved. Using this pattern, decision is
                                                                           taken by the IADMP.

                                                                           C. HDMP (Hybrid Decision Making Protocol)
                                                                              The Hybrid DMP performs the functions based on the
                                                                           BBSS Protocol using RSS with IADMP information. The
                                                                           IADMP makes decision from the history of the Mobile node
               Figure 10. Proposed Handoff Architecture
                                                                           which is based on the data mining operations. The BBSS
    As shown in Figure 10 the Proposed Handoff architecture                Protocol finds the better base station using signal strengths.
[9] has seven modules. The Neighbour Discover unit discovers               Figure 11 shows the procedure for Hybrid DMP.
the neighbouring base station based on signal strength and

                                                                                                      ISSN 1947-5500
                                                        (IJCSIS) International Journal of Computer Science and Information Security,
                                                        Vol. 9, No. 1, January 2011

                                                                                    Figure 12. Destination time Vs Signal Strength

                                                                           Figure 12 shows the graph for Destination time Vs Signal
                                                                       strength. When the mobile node moves to base station the
                                                                       destination time decreasing, simultaneously the signal strength
                                                                       of the mobile node increases.

                                                                           TABLE VIII.    COMPARISON OF DELAY IN DIFFERENT PROTOCOLS

                      Figure 11. Hybrid DMP

    The HDMP (Hybrid Decision Making Protocol) is a mixing
of IADMP and BBSSP. The HDMP is compared with Double
Threshold Protocol (DTP) and BBSSP. The simulation works
are performed with different speed of mobile node and the
results are tabulated in table VI.                                         The table VIII shows the comparison of different protocols,
                                                                       in this table delay refers to the time taken to send signal from
                                                                       Mobile node to MSC through BSC, as well as
      TABLE VI.      MEASUREMENT ANALYSIS OF MOBILE NODE               acknowledgement signal is sent back from Mobile node to
                                                                       correspondent BSC to remove old information. The Double
                                                                       Threshold Protocol has two threshold points to alert the
                                                                       handoff initiation. In this protocol the delay is high as shown in
                                                                       the table VIII. The Better Base Station Selection Protocol
                                                                       (BBSSP) selects the better base station for handoff using RSS
                                                                       (Relative Signal Strength) and ASS (Absolute Signal Strength).
                                                                       Hence the IADMP (Intelligent Agent Decision Making
                                                                       Protocol) takes less delay than BBSSP when handoff occurs.
                                                                       The HDMP (Hybrid Decision Making Protocol) is the
                                                                       combination of BBSSP and IADMP. The HDMP makes less
                                                                       delay than other protocols.
   Table VII shows the measurement analysis of Handoff. The
handoff initiation takes place before Mobile node reaches the


                                                                                Figure 13. Graphs for Comparison of Handoff Protocols

                                                                                                     ISSN 1947-5500
                                                                    (IJCSIS) International Journal of Computer Science and Information Security,
                                                                    Vol. 9, No. 1, January 2011

    Figure 13 shows the comparison of delay for different                             [8]    Jochen H.Schiller(2006), “Mobile Communications” Pearson Education,
handoff Protocols. As shown in the graph HDMP takes less                                     Ltd.
delay in Handoff.                                                                     [9]    Liebsch.M, A.Singh, H.Chaskar, D.Funato and E.Shim, (2004),
                                                                                             “Candidate Access Router Discovery”, Internet Draft, Internet
                                                                                             Engineering Task Force, draft-ietf-seamoby-card-protocol-07.txt.
      IV.    CONCLUSIONS AND FUTURE ENHANCEMENT                                       [10]   Ning Zhang and Jack M.Holtzman (1996), ”Analysis of Handoff
                                                                                             algorithms using absolute and Relative measurements” IEEE
   In mobility management, the following techniques are                                      transactions on Vehicular Technology, Vol. 45, No. 1.
implemented i) RUR Algorithm ii) ETU (Enhanced Temporal                               [11]   Patricia Serrano-Alvarado, Claudia Roncancio, Michel Adiba, (2004),
Updation) technique iii) DTP (Double Threshold Protocol) iv)                                 “A Survey of Mobile Transactions”, Source Distributed and Parallel
IADMP (Intelligent Decision Making Protocol) and v) HDMP                                     Databases archive Vol. 16 , Issue 2 .
(Hybrid Decision Making Protocol) using Network simulator 2.                          [12]   Shantidev Mohanty and Ian F.Akyildiz, (2006), ”A Cross-Layer (Layer
                                                                                             2 + 3) Handoff Management Protocol for Next-Generation Wireless
A. Conclusion                                                                                Systems”, IEEE Transactions.
                                                                                      [13]   Shiow-yang Wu and Hsiu-Hao Fan (2010), “Activity-Based Proactive
                                                                                             Data Management in Mobile Environments” IEEE Transactions on
    Location management and Handoff management protocols                                     Mobile Computing, Vol. 9, No. 3.
are implemented and improved the Quality of Service in                                [14]   The Ns Manual
mobile networks. The proposed handoff architecture is                                 [15]   Theodore S. Rappaport (2007), “Wireless Communications Principles
designed to provide the continuous service to mobile user. The                               and Practice” Prentice-Hall of India Private Ltd. New Delhi.
Service providers and subscribers are more benefited due to the                       [16]   Xian Wang, Pingzhi Fan, Jie Li and Yi Pan, (2008) Modeling and Cost
technical advancement. Hence these protocols and algorithm                                   Analysis of Movement-Based Location Management for PCS Networks
                                                                                             With HLR/VLR Architecture, General Location Area and Cell
can be used in the next generation wireless communications                                   Residence Time Distributions”, IEEE Transactions on Vehhicular
systems to reduce the location management signalling costs.                                  Technology, Vol. 57, No. 6.

                                                                                                                 AUTHORS PROFILE
B. Future Enhancement                                                                               Selvan.C is doing his research in the area of Mobile
    In coming years, IADMP will play major role in mobile                                           Computing in the Department of Computer Science
computing. The Intelligent Agent decision making protocol                                           and Engineering in Government College of
will be adapted with existing protocols without making any                                          Technology, Coimbatore, Tamil Nadu, India. His
difficulties. Of course, numerous protocols may be created to                                       research work is supported by University Grant
improve QoS but the requirement of the subscribers necessity                                        Commission, New Delhi, India. He has registered
may be varying based on the technological advancement. It                                           his research in Anna University of Technology,
may increase the software maintenance cost and system                                 Coimbatore, Tamil Nadu, India. His area of interest is Mobile
complexity, but there is no question for failure of the handoff                       Computing and Mobile Communication. He is the student member of
                                                                                                        Dr.R.Shanmugalakshmi is working as an Assistant
                             ACKNOWLEDGMENT                                                             Professor in the Department of Computer Science
             We would like to express our cordial thanks to                                             and Engineering in Government College of
Dr. V. Lakshmi Prabha for her full support and valuable                                                 Technology, Coimbatore, Tamil Nadu, India. She
                                                                                                        has published more than 40 International / National
suggestions to continue our research work.
                                                                                                        Journals. Her research area includes Image
                                                                                                        processing, Neural Networks and Mobile
                                  REFERENCES                                          Computing. She has received Vijya Ratna Award from India
[1]     Abhishek Roy, Archan Misra and Sajal K. Das (2007), “Location                 International Friendship Society in the year of 1996. She has received
        Update versus Paging Trade-Off in Cellular Networks: An Approach              Mahila Jyothi Award from Integrated Council for Socio-Economic
        Based on Vector Quantization”, Vol 6, pp. 1426 – 1440.                        Progress in the year 2001 and she has received Eminent
[2]     Abraham Silberschatz, Henry F.Korth and S.Sudarshan(2006), MC                 Educationalist Award from International Institute of Management,
        Graw Hill Highe Education publication, “Database System Concepts”             New Delhi in the year of 2008. She is a member of Computer Society
        pp. 723-753.                                                                  of India, ISTE and FIE.
[3]     I.F. Akyildiz et al. (2007), “Mobility Management for Next Generation
        Wireless Systems” Proc. IEEE, Vol. 87, No. 8, pp. 1347-1384.
[4]     Ezil Sam Leni. A and Srivatsa. S. KH (2008), “A Handoff Technique to
        Improve TCP Performance in Next Generation Wireless Networks”,
        Information Technology Journal 7(3). pp. 504-509.
[5]     Ian F.Akyildiz and Wenye Wang (2002), “A Dynamic Location
        Management Scheme for Next Generation Multitier PCS Systems”,
        IEEE Transactions on Wireless communications, Vol. 1, No. 1.
[6]     Jiawei Han and Micheline Kamber (2001), “Data Mining Concepts and
        Techniques”, Morgan Kaufmann Publishers (An imprint of Elsevier).
[7]     Jin Soung Yoo, Shashi Shekhar. (2009), “Similarity-Profiled Temporal
        Association Mining” IEEE Transactions on Knowledge and Data

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