2. David Lynn Presents… HANDOVER IN MOBILE WIMAX NETWORKS: THE STATE OF ART AND RESEARCH ISSUES Sayan Kumar Ray Krzysztof Pawlikowski Harsha Sirisena

3. HARD HANDOVERS Acquisition Phase BS advertises the Network Topology Scanning of advertised neighboring BSs and MS Ranging and Optional Association Activates Actual Handover Phase Deciding on the TBS Initiating the Handover TBS synchronization and Ranging Process Authorization and Registration Phase

4. FAST BASE STATION SWITCHING HANDOVERS Diversity Set Updating Updating and Selecting the new ABS Handover Occurrence

5. RESEARCH ISSUES: LAYER 2 HANDOVER ISSUES Excessive Scanning and Associating Activates Optimizing Scanning Interval Efficient Exploitation of DL and UL Signals Wastage of Ranging Slots Prolonged Handover Connection Disruption Time Network Re-Entry Activity due to Ping Pong Effects IP Connectivity Delay during Network Re-entry Optimizing Handover-based Load Distribution http://www.integration1.com.au/NetSecScanInfo.htm http://chaka4612.blogspot.com/2011/11/family-time-and-ping-pong.html http://www.playslots.org.uk/http://science.howstuffworks.com/apollo-spacecraft7.htm http://www.winnersedgetrading.com/forex-signal-gbpusd/ http://directorblue.blogspot.com/2008/12/importance-of-load-distribution.html http://cnx.org/content/m13596/latest/

6. RESEARCH ISSUES: LAYER 2 HANDOVER SOLUTIONS Select the potential TBS before the scanning operations. NBSs can exchange configuration parameters. MS’s uplink signal strengths and SBS’s downlink signal strengths. Selection of the TBS prior to the handover preregistration phase. MAC management message can enable the MS to receive traffic immediately after the handover. Traffic for MS will remain buffered in the SBS for a set amount of time. TBS know the MS’s previous AR and the IP address. BS-initiated directed handovers and MS- initiated rescue handovers are conducted in parallel.

7. RESEARCH ISSUES: LAYER 3 HANDOVER ISSUES Large L3 Handover Latency MAC State Migration Problem Interworking with MIPv6 http://applewallpapers.net/view/mac_os_wallpaper-1440x900.html http://capitalmarketalerts.com/living-with-no-growth/slow-road-sign-378px/ http://anchorsholme.org.uk/2012/01/2580/hand-over-keys/

8. RESEARCH ISSUES: LAYER 3 HANDOVER SOLUTIONS Timely indication of organized L2 triggers. Serving network can buffer the IP packets meant for the MS to reset the lost MAC frames. FMIPv6, HMIPv6 and PMIPv6.

9. RESEARCH ISSUES: LAYER 2&3 HANDOVER ISSUES & SOLUTIONS Explicit HO Notification to Upper Layers Imprecise L2 TriggersSeamless Integration of L2 and L3 Mobility Management Messages Two-Way Cross-Layer Handover Information Flow http://news.softpedia.com/newsImage/Imprecise-Chips-Could-Revolutionize-Electronics-2.jpg/ http://hackbymak.blogspot.com/2012/02/get-notification-when-any-program.html http://dna-of-humancapital.blogspot.com/2011/03/end-of-managementlong-live-management.html http://www.nowpublic.com/environment/massive-river-flow-through-arctic Explicit L2 to L3 event triggers during the various stages of the overall MWiMAX HO activity. Send the L2-HO trigger early enough to the upper layers in the form of predicted RSSI values. Removal of related HO management messages from both the MWiMAX L2 and L3 HO. Multiple event and command services to improve the FMIPv6 HO support over the MWIMAX MAC.