"IMPOSSIBLE " says "I AM POSSIBLE "

  For Part 1: https://tomar102003.blogspot.com/2022/10/5g-call-flow-registration-procedure.html As in part-1 we have already discussed Registration procedure . Now we will discuss Deregistration Procedure and PDU Session Establishment . So, First Start with Deregistration. We know that if UE(User Equipment) wants to use services of 5G then it have to first register it with the network through the registration procedure . But there is a time when UE  don't want to take services, and wants to deregister from the network so it have to sends the request for deregistration or if a network want to kick out particular UE then, this procedure is also used in this case . ProDeveloperTutorial.com 1. As you can see in the above image that UE sends the deregistration  request   to AMF through RAN.Now AMF sends the request to the SMF for releasing any User related context or any PDU Session associated with this UE. 2. SMF sends the request to the UPF for releasing any ongoing PDU session associ

  Let's have a look on 5g call flow of registration procedure . Source-ScienceDirect.com As you can see in the above image that UE has to register itself before using the 5g services . The registration are of several types which are listed down below: Initial Procedure Registration Periodic Procedure Registration Mobility Procedure Registration Emergency Procedure Registration In Initial Procedure, when UE is Power-On and ready for registration .Periodic procedure is to keep watch of UE status , if it become inactive , due to some reasons like  battery discharge .Mobility procedure is when UE move to another location and then it have to register it, under this procedure.Emergency procedure is when there is any emergency like situations ,then this procedure is used. Now lets a deep dive how a UE Register itself to a 5g network for using its services. 1. For a registration from UE , it send a registration request to RAN(gNB). Now RAN sends this request to the AMF(Access and Mobility

  For Part-1 of RAN Protocol Stack : https://tomar102003.blogspot.com/2022/09/ran-protocol-stack-overview-part-1.html For Part-2 of RAN Protocol Stack : https://tomar102003.blogspot.com/2022/10/ran-protocol-stack-part-2.html So , in part 2 we have discuss till the MAC Layer now we have to discuss PHY Layer which is left in User-Plane , RRC Layer and NAS Layer of Control-Plane as all left layer of Control-Plane are same as User-Plane which we have discussed already in part-2 of this series. 1. PHY ( Physical ) Layer : Source -techplayon.com As you can see in above image that Physical Layer getting its services from the Transport Channel(which is a part of MAC Layer) ,hence getting services from MAC. So first take a look on the Physical channels: PDCCH ( Physical Downlink Control Channel ) :This channel is used for downlink control information like scheduling sessions. PBCH ( Physical Broadcast Channel ) : This channel have the system information which is used by UE for getting the MIB(

For Part-1 of RAN Protocol Stack : https://tomar102003.blogspot.com/2022/09/ran-protocol-stack-overview-part-1.html In the below image, we have all layers of User Plane Protocol Stack . Now From top to bottom, we will go through each layer with wide description of each functions within each layer.  source - techplayon.com 1. SDAP ( Service Data Adaptation Protocol ): Functions of this layer are : QoS ( Quality of Service ) Flow Handling : This layer mapped the quality of service , QFI (Quality of Service Flow ID) to the appropriate radio bearer between the gNodeB (RAN) and the UE (User Equipment or Device).           QFI(Quality of Service Flow ID): It is used to differentiate between different quality of service within the PDU's (Protocol Data Unit) Sessions.           Below Image give you the overview about what we describe above. source - techplayon.com As you can see that QoS Flow are giving their QFI for differentiate between different quality of service within a PDU Sessio