LTE - Signaling stacks eNB [Under LTE]
» E-UTRA and E-UTRAN overall description - 36.300, Rel 8 «
» E-UTRAN access - 23.401, Rel 8 «
Here our focus would on signaling entities at eNode B.
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AT interface
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Adaptor
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ESM
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EMM
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RRC
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PDCP
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RLC
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MAC
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PHY
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RRM/Relay
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RRC
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S1AP
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PDCP
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SCTP
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RLC
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IP
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MAC
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L2
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PHY
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L1
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MME AL
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ESM
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GTP-C
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EMM
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S1AP
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SCTP
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UDP
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IP
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IP
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L2
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L2
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L1
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L1
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SGW AL
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GTP-C
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UDP
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IP
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L2
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L1
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Towards PGW
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| UE |
SRBs
(RRC SRB0/1/2,
MAC LCID 0/1/2)
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eNB |
S1
(S1AP ID)
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MME |
GTP-C
(IMSI,
EPS bearer ID)
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SGW |
| .. |
RRM/Relay
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UE contexts [IMSI, S1AP IDs, bearer IDs, QoS etc.]
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.. |
36.300:16, radio bearer control, radio admission control, idle/connected mode mobility/handover, load balancing, inter-RAT RRM |
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Towards UE (Uu interface)
| .. |
RRC
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Control
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UE1
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. . .
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UEn
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SRB0/1/2
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SRB0/1/2
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.. |
36.331, signaling connection management/configuration, data radio bearer configuration, measurement reporting, configuring AS ciphering and integrity protection, system info broadcast, paging, handover |
| .. |
PDCP
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Control
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UE1
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. . .
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UEn
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SRB1/2
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. |
DRB1..11*
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SRB1/2
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. |
DRB1..11*
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.. |
36.323, integrity protection, ciphering
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa |
| .. |
RLC
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Control
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UE1
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. . .
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UEn
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SRB0/1/2
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. |
DRB1..11*
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SRB0/1/2
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DRB1..11*
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.. |
36.322, buffering, segmentation, concatenation, reassembly, ARQ |
| .. |
MAC
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Control
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UE1
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. . .
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UEn
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| Logical channels |
| Transport channels |
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| Logical channels |
| Transport channels |
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.. |
36.321, channel mapping, multiplexing, channel prioritisation, HARQ, scheduling |
| .. |
PHY
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Channel mapping & phy procedures
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36.201 modulation, coding, power control, cell search, measurements, CRC insertion and other phy specific procedures |
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Towards MME (S1MME interface)
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36.413, UE context management, ERAB management, NAS transport |
| .. |
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.. |
IETF rfc3309/rfc4106, signaling transport over IP, one association for all UEs |
| .. |
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.. |
IETF rfc791, IP backbone
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa |
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* as per RRC TS 36.331, sec 6.4, maxDRB is 11; but as per MAC TS 36.321, section 6.2.1, 11 LCIDs are possible, three of which goes for SRB 0-2, leaving maximum 8 for DRBs !
In next article, we will look at signaling entities at MME.
References: 3G Evolution: HSPA and LTE by Dahlman,
Parkvall, Sköld, and Beming, LTE - From Theory to
Practice, Edited by Sesia, Toufik, and Baker, and SAE and the
Evolved Packet Core: Driving the Mobile Broadband Revolution by
Olsson, Sultana, Rommer, Frid, and Mulligan.
| Copyright © Samir Amberkar 2010-11 | § |
