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1、2-1,CDMA网优技术和实际案例学习培训,CDMA关键参数及切换算法介绍,2-2,CDMA网优技术和实际案例学习培训,Contents of this Lecture,Acquire the System Idle Mode Handoff Access Handoff Traffic Handoff Practical Consideration,2-3,CDMA网优技术和实际案例学习培训,Acquire the System,CDMA Handoff: Part I,FAQ :,Whats happened after we ture on the handset,4,CDMA网优技术和
2、实际案例学习培训,Mobile scans forward link frequencies: (Cellular or PCS, depending on model) History List Preferred Roaming List until a CDMA signal is found. NO CDMA?! Go to AMPS, or to a power-saving standby mode,Find a Frequency with a CDMA RF Signal,5,CDMA网优技术和实际案例学习培训,Find Strongest Pilot, Read Sync C
3、hannel,6,CDMA网优技术和实际案例学习培训,Rake Fingers,?,Reference PN,Active Pilot,Keep Rake finger(s) on strongest available PN, decode Walsh 1, and monitor the Paging Channel,Go to Paging Channel 2HO REQUIRED MESSAGE; 3HO REQUEST MESSAGE; 4HO REQUEST ACK; 5HO CAMMOND MESSAGE; 6UHDM; 7HCM.,Inter MSC Hard Handoff
4、Process,34,CDMA网优技术和实际案例学习培训,Inter MSC Hard Handoff Process,35,CDMA网优技术和实际案例学习培训,Inter FA Hard Handoff Type Overview,Common FA Pilot Beacon HPBA Dummy Pilot,36,CDMA网优技术和实际案例学习培训,Common FA,This is inter- FA Hard Handoff that is performed without Pilot Beacon or Dummy Pilot. The system receives PSMM p
5、eriodically, when mobile station moves into a BTS of which FA configuration is different from neighbor BTS. The system determines terminal is remote enough from the current BTS by the reduction degree of current Ec/Io value reported by terminal, performing Intra Cell FA Hard Handoff through Common F
6、A of Serving BTS and Target BTS.,37,CDMA网优技术和实际案例学习培训,Common FA Call Flow,38,CDMA网优技术和实际案例学习培训,Pilot Beacon,For inter-frequency handoff, terminal is to search access to target BTS. Therefore, it is required that Pilot Beacon transmitter is installed to transmit pilot signal only of which call channe
7、l is not included in target BTS. Inter-frequency hard handoff is mainly performed on the downtown boundary and inter-operator handoff area that the FA number used by each BTS is different.,39,CDMA网优技术和实际案例学习培训,Pilot Beacon Call Flow,40,CDMA网优技术和实际案例学习培训,Pilot Beacon Samsung Realization,Dummy Pilot A
8、 physical FA without traffic channel HPBAA single board which can simulate 3 Dummy Pilot function,but Only pilot channel supported. (In PICO,STRA implements the Hopping Pilot Beacon without any additional H/W,and supports the neighboring FA up to 3FA.),41,CDMA网优技术和实际案例学习培训,Enhanced Hard Handoff,Supp
9、orts IS-95B and IS-2000 Standard Enhanced Hard Handoff is the function that enhances inter-FA hard handoff success rate without other equipment of Pilot Beacon or Dummy Pilot, by terminal transferring Serving and Candidate frequencies and measuring Candidate frequency Pilot strength. Terminal measur
10、es the pilot signal strengths of other frequencies (once or periodically). Terminal is enabled to return to the serving frequency previous to hard handoff attempt, when FA hard handoff is fail.,42,CDMA网优技术和实际案例学习培训,Enhanced Hard Handoff Call Flow,43,CDMA网优技术和实际案例学习培训,Handoff Process,A typical soft h
11、andoff process,Pilot Strength,Pilot Strengthexceeds T_ADD,EHOD message received, Pilot Dropped into Neighbor Set, HOC message sent,NLU message received,Time,Pilot strength drops below T_DROP,Drop Timer started,T_TDROP,T_ADD,T_DROP,EHOD message received, Pilot Added to Active Set,HOC message sent,NLU
12、 message received,N,C,N,A,(1),(2),(3),(4),(5),(6),(7),Drop Timer expires,PSMM sent (request to add) , Pilot added to Candidate Set,PSMM Sent (request to remove),44,CDMA网优技术和实际案例学习培训,2-45,CDMA网优技术和实际案例学习培训,Detail Flow and Typical Message as Followed Pages,Ec/Io,All PN Offsets,0 0,32K 512,Chips PN,0,-
13、20,Neighbor Set,The call is already in progress. PN 168 is the only active signal, and also is our timing reference. Continue checking the neighbors.,If we ever notice a neighbor with Ec/Io above T_ADD, ask to use it! Send a Pilot Strength Measurement Message!,T_ADD,10752 168,32000 500,14080 220,!,!
14、,Call is Already Established.What Next?,46,CDMA网优技术和实际案例学习培训,Just prior to this message, this particular mobile already was in handoff with PN 168 and 220. This pilot strength measurement message reports PN 500 has increased above T_Add, and the mobile wants to use it too.,The base station acknowled
15、ges receiving the Pilot Strength Measurement Message.,Mobile Requests the Handoff,47,CDMA网优技术和实际案例学习培训,The base station sends a Handof Direction Message authorizing the mobile to begin soft handoff with all three requested PNs. The pre-existing link on PN 168 will continue to use Walsh code 61, the
16、new link on PN220 will use Walsh Code 20, and the new link on PN500 will use Walsh code 50.,The mobile acknowledges it has received the Handoff Direction Message.,System Authorizes the Handoff,48,CDMA网优技术和实际案例学习培训,The mobile searcher quickly re-checks all three PNs. It still hears their pilots! The mobile sends a Handoff Completion Message, confirming it still wants to go ahead with the handoff.,18:14:54.920 Forward Tr
