tailieunhanh - Handbook of Wireless Networks and Mobile Computing phần 2

và bộ nhớ cache của chúng tôi là không có khả năng để làm một công việc tốt hơn. Bộ nhớ cache của chúng tôi sẽ làm việc trong một cluster? Điều này thường không phải là một vấn đề đối với dữ liệu tham khảo: nó không phải là một vấn đề nếu mỗi máy chủ có bản sao riêng của mình chỉ đọc dữ liệu, | LOCATION MANAGEMENT SCHEMES 37 triangles. For each reporting cell z its vicinity is defined as the collection of all nonreporting cells that are reachable from cell Ỉ without crossing another reporting cell. The reporting cell belongs to its own vicinity. For example the vicinity of cell c includes cells A c and F in Figure . A mobile station will update its location . cell ID whenever it moves into a new reporting cell. For example when a mobile station moves from cell B to cell A then to cell c in Figure it will report its new location because cell B and cell c are two different reporting cells. However if a mobile station moves fromTell BtoGcBAthcnmovp back into cell B no location update is necessary. When an incoming call arrives for a mobile station the cellularsystemwillpage all cells withinthe vi cinityofthereportingnellthat waslastrepo rteiibyiarniobSc slalion. The eehortàngsellsapneaacnis aesoglobclih iheeansethatallmobllettatlonstfansmit thpta rytatianupdatps in the same set of reporting cells and it is static in the sense that reportinccells are Sixed it e3l. Theteportingcells eppropah alsshac twfextssmespses ylwnys-ufiiate endicycltupdaie. In theaiwaye-ucPalt casc every scllis n eiectep is a mobliettnlipnneeds teupdatells iycrtienwhenrves itenieasanew yplt. A- bl tr . cost oftocationupdats i s vpsyhigh bulthyap isno nagint coss. I etlc nevcT-lipdatpp asp svpeyyettls tinlR Ịtdrtilrg ylerrU le dnreisny rttss of ipp aticniipl thp paglnc rostlrvpry Ugh pppausslhs c ili la sylpmtipc - ll pagp rvarpts 11 in thls ealyl crtalofindpur thp ppll in whiph thp mobilp station is purrpntly ishow toypip rtasubspt ot raperting satlsto rnmimidsthp totetidcai tion managpmnytryst whiahtn thtsumyfthp ll n tudatpp ost cld thapagiphposs. ThpibaaodrpporSmg ppntprrSpallshysbceu blrttpropprediniP P tlleautlaotrde-bna aieaostot tg itli best on the 1 aage ti piaiiiityiitthenaltiDrl apbfuspSPaabsS y tp allng