A SATELLITE NETWORK ARCHITECTURE FOR A MEO CONSTELLATION IN A GLOBAL PERSONAL COMMUNICATION SYSTEM

7/31/2019 A SATELLITE NETWORK ARCHITECTURE FOR A MEO CONSTELLATION IN A GLOBAL PERSONAL COMMUNICATION SYSTEM

1/33

A SATELLITE NETWORKARCHITECTURE FOR A MEO

CONSTELLATION IN A GLOBALPERSONAL COMMUNICATION

SYSTEM

SUBMITTED BY

VANI DEVI.PS1 M-TECH

ROLL NO:35


2/33

Contents1. Introduction2. Network Architecture3. Call Routing Scenarios4. Network Mobility Management5. Handover Types6. MAGSS-14 characteristics7. Advantages

8. Limitations9. Applications10. Conclusion11. References


3/33


4/33

Continued GS user terminal (UT),

primary earth station(PES),

primary earth station controllers (PES/c),inter networking with fixed n/ws &Public Land mobile Networks (PLMNs)


5/33

NETWORK ARCHITECTUREUTs interface with user & PESs interface with terrestrialn/wsMain task of satellite resource managemant is located atPES/csAt any time satellite will be under the control of a singlePES/cDuring a hand over transaction two PES/cs from two

different PES/cLs are involved


6/33

Continued


7/33

PES/cL layout


8/33

Network Architecture


9/33

Whole n/w is supervised by NMC(Network ManagementCentre)

PES/cs have distributed control functionsNMC will act only in case of unexpected situationsEach PES/cL contains DB(DataBases)DBs handle the mobility management and authentication

functions


10/33

Call Routing Scenarios

4 call routing scenarios(1)b/w two UTs visible from same PES/c

(2)b/w two UTs not visible from same PES/c(3)b/w UT & fixed phone not visible from the same PES/c(4)b/w UT & fixed phone visible from same PES/c


11/33

(1) Call involving two UTs visible from the

same PES/c


12/33

(2) Call involving two UTs not visible fromthe same PES/c

When a call between UTs involves more than onePES/c,there are two possibilities

When both PES/cs belong to the same PES/cL:-delay in the terrestrial links is very small

When both PES/cs belong to different PES/cL


13/33


14/33

(3) Call involving a UT and a fixed phone not visiblefrom the same PES/cL


15/33

(4) Call involving a UT and a fixed phone visiblefrom the same PES


16/33

N/w Mobility Management

Three procedures:Location registration, Paging and HandoverLocation registration is the action taken by UT to informthe VLR and eventually the HLR about its position in thenetwork to allow the possibility of routing mobileterminated callsPaging relates to the procedures that the network mustperform to contact a UT in a certain location Area (LA)incase of UT terminated calls


17/33

Trade Off between Paging and LA

Less paging of UT is required if n/w knows theUTs position with more certainity (small LA).

For small LA size more location registrations arerequired.So the size of the LA is directly related to theamount of signalling in the network


18/33

Location Area size trade off


19/33

Location Area,satellite ID,spot beam ID


20/33

VLRs store the sat ID for each UT that is registered with aspecific satellite.To facilitate handovers the separation of the informationrelated to each satellite is made in the VLRPES/c ID is not necessary in this case since the UTs neednot know which PES/c is controlling it.HLR contains the PES/c ID


21/33

Registration

All satellites broadcast their ID (SAT ID) in a specificchannel SBCCH (Satellite Broadcast Control CHannel)UT switched on searches for all possible broadcastchannelsextracts SAT ID & parameters of the bestchannelskeeps a list of best broadcast channels involatile memory(for hand over purposes)UT registerswith the best visible satellitePES/c informs VLR & HLR accordingly


22/33

Location Update

UT periodically measures the quality of received channelsfrom visible satellites detects a better channel receivedfrom another satelliteinitiates a location updatesendsthe new SAT ID to the VLRasks old VLR thepermission to register the UT & transfer all the data relatedto the UTinforms HLR if it is in a new PES/cL


23/33

Handover

Handover is an operation that a mobile network mustsupport to avoid a call being interrupted when a UT isno longer visible from a Base Station (Spot beam of asatellite )Two types:- (1) hand over of a UT

(2) hand over of a satellite


24/33

(1) Handover of a UT


25/33

UT must keep measuring periodically the quality of thereceived broadcast channels from several visible spotbeams.This enables the network to decide when a handover isrequiredAfter handover ,a terrestrial link between PES/cLs is used.If there is no available channels in the new spot beam,another spot beam must be tried.Limited time is a limitation.


26/33

(2) Handover of a satellite


27/33

A signalling between PES/cs is necessary.The satellite resource information (SRS) must betransferred from old PES/cL to the new PES/cL.To avoid the hand over of many calls,a time interval duringwhich the resources management of the satellite is made bythe new PES/cL,while the old calls remain through the oldPES/cL.If a call lasts longer than the mentioned interval,a handoveris necessary.


28/33

MAGSS-14


29/33

Advantages

Large coverage areaFlexible N/w Services

Global connectivityMultimedium applicationsBest handover


30/33

Limitations

Delay & Doppler effectLow link margin

Spectrum & orbit matters


31/33

Applications

In navigationIn remote sensing

In telephoneData communication


32/33

Conclusion

A network architecture for MEOconstellation has been identified and shown that a

minimum of six PES/cLs is required to enable a totalcontrol of satellites.Due to limitations of power & G/T, thecommunication between two UTs directly through asatellite is not allowed.A UT to UT call is carried outthrough a PES/c & never through a PES.A mobilitymanagement scheme &several handover types have beenidentified.


33/33

REFERENCES

Documents

A SATELLITE NETWORK ARCHITECTURE FOR A MEO CONSTELLATION IN A GLOBAL PERSONAL COMMUNICATION SYSTEM