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Contex & problem statementContention-based random access: 4-steps procedure
Collision scenarioAccess capacity evaluation
Perspectives
Random access procedure capacityevaluation in LTE-A
Soukaina Cherkaoui Herve Rivano Fabrice Valois
(1)
(2)
27, March 2015
1 / 24 Soukaina CHERKAOUI Random access procedure capacity evaluation in LTE-A
Contex & problem statementContention-based random access: 4-steps procedure
Collision scenarioAccess capacity evaluation
Perspectives
Outline
1 Contex & problem statementAccess capacity of a cellSlotted aloha
2 Contention-based random access: 4-steps procedure
3 / 24 Soukaina CHERKAOUI Random access procedure capacity evaluation in LTE-A
Contex & problem statementContention-based random access: 4-steps procedure
Collision scenarioAccess capacity evaluation
Perspectives
Access capacity of a cellSlotted aloha
Targeted environment
Dense cellsSmall packets
Smartphones
MTC i.e sensors of smart-*environment
Access capacity of a Cell?
4 / 24 Soukaina CHERKAOUI Random access procedure capacity evaluation in LTE-A
Contex & problem statementContention-based random access: 4-steps procedure
Collision scenarioAccess capacity evaluation
Perspectives
Access capacity of a cellSlotted aloha
Netwok access metrics
Access Capacity:Number of successful simultaneous accessUnit = number of succesful access request/ period
Blocking probabilityNumber of failed request access
Access delay
5 / 24 Soukaina CHERKAOUI Random access procedure capacity evaluation in LTE-A
Contex & problem statementContention-based random access: 4-steps procedure
Collision scenarioAccess capacity evaluation
Perspectives
Access capacity of a cellSlotted aloha
1st random access protocolSatellite system, wireless..Principle:
When a node has a packet to send, itwaits unitil the beginning of the next slotIf no other nodes attempt transmissionduring that slot, the transmission issuccessful
Otherwise, CollisionCollided packet are retransmitted aftera random delay
Capacity evaluation in term of throughput
6 / 24 Soukaina CHERKAOUI Random access procedure capacity evaluation in LTE-A
Contex & problem statementContention-based random access: 4-steps procedure
Collision scenarioAccess capacity evaluation
Perspectives
Access capacity of a cellSlotted aloha
Access management techniques
7 / 24 Soukaina CHERKAOUI Random access procedure capacity evaluation in LTE-A
Contex & problem statementContention-based random access: 4-steps procedure
Collision scenarioAccess capacity evaluation
Perspectives
Access capacity of a cellSlotted aloha
Always Aloha for cellular networks access
Core of the access process in cellular networksfreedom degrees:
Contention spaceResources
Idea: decrease message lengthAloha: Full messageCSMA/CA: RTS/CTSLTE: preambles
Limit: ability to distinguish users
8 / 24 Soukaina CHERKAOUI Random access procedure capacity evaluation in LTE-A
Contex & problem statementContention-based random access: 4-steps procedure
Collision scenarioAccess capacity evaluation
Perspectives
Outline
1 Contex & problem statementAccess capacity of a cellSlotted aloha
2 Contention-based random access: 4-steps procedure