Full Stack

Now that we covered each layer of LTE protocol stack, it is time to combine all these layers to a complete protocol stack.

• Overall Sequence and Layer Configuration
• Downlink Channel Map
• Uplink Channel Map
• Channel Mapping Table throughout Call Processing
• Live Network Examples in Fullstack

Overall Sequence and Layer Configuration

Try to follow the sequence below and combine all the knowledges you have and try to make practical sense out of it. This kind of integration is something not explanined in 3GPP specification and you have to figure out on your own.

Couple of bullet points for you to follow up are as follows :

• i) Which of the sequence requires normal MAC header and which of them does not use any MAC header ?
• ii) What is the practical meaning of "No MAC Header" and "Normal MAC Header" ?
• iii) Which process use RLC TM mode ? Which Process use RLC UM mode and Which process use RLC AM mode ?
• iv) Can you explain the detailed RLC layer behavior of each processes which is using RLC layer ?
• v) Which process use PDCP and which does not ?

No MAC Header, RLC TM , No PDCP

No MAC Header, RLC TM , No PDCP

No MAC Header, No RLC , No PDCP

No MAC Header, No RLC , No PDCP

UL SCH -> UL CCCH

MAC Header, No RLC , No PDCP

RRC Connection Request

DL CCCH -> DL SCH

MAC Header, No RLC , No PDCP

RRC Connection Setup

UL SCH -> UL DCCH

MAC Header, RLC AM , PDCP

RRC : RRC Connection Setup Complete +

NAS : Attach Request (ESM:PDN Connectivity Request)

DL DCCH -> DL SCH

MAC Header, RLC AM , PDCP

EMM : Authentication Request

UL SCH -> UL DCCH

MAC Header, RLC AM , PDCP

EMM : Authentication Response

DL DCCH -> DL SCH

MAC Header, RLC AM , PDCP

EMM : Security Mode Command

UL SCH -> UL DCCH

MAC Header, RLC AM , PDCP

EMM : Security Mode Complete

DL DCCH -> DL SCH

MAC Header, RLC AM , PDCP

RRC : Security Mode Command

UL SCH -> UL DCCH

MAC Header, RLC AM , PDCP

RRC : Security Mode Complete

DL DCCH -> DL SCH

MAC Header, RLC AM , PDCP

RRC : RRC Connection Reconfiguration

EMM : Attach Accept

ESM : Activate Default EPS Bearer Context Request

UL SCH -> UL DCCH

MAC Header, RLC AM , PDCP

RRC : RRC Connection Reconfiguration Complete

UL SCH -> UL DCCH

MAC Header, RLC AM , PDCP

EMM : Attach Complete

ESM : Activate Default EPS Bearer Context Accept

DL DCCH -> DL SCH

MAC Header, RLC AM , PDCP

RRC : RRC Connection Release

NOTE : You can double check on these configuration in 36.331 summarized in SRB page.

Downlink Channel Map

The diagram you saw above a kind of message flow(event diagram) in time sequence. The diagram shown below is not a time based, but it shows the channel mapping (or data flow across the full protocol stack). Pick one of the message from the diagram shown above and try to find right route for this digram and see how much details you can add.

For example, if you picked the message "RRC Connection Setup", the start point would be "RRC Message msg4".

Following is a tabular presentation of DL Channel Map. (LCID and TrCH Number would be different depending on the network or Network Simulator)