UMTS/3G Architecture

 The UMTS network can be broadly divided into-

  • User Equipment(UE)
  • Radio Network Subsystem(RNS)
  • Core Network(CN)
UMTS/3G Architecture
  1. User Equipment(UE) :
  • USIM(Universal Subscriber Identity Module) :Same as SIM card, But in case of UMTS it is termed as USIM.
  • ME(Mobile Equipment) :Hardware used by subscriber containing IMEI.
      2.Radio Network Subsystem(RNS) :Also known as UMTS Radio Access Network,(UTRAN).It            provides and  manage the air interface for the overall network.
  • Node B : Node B corresponds to BTS in GSM.
  • RNC(Radio Network Controller) :It controls Node B in 3G telecom system.
      3.Core Network(CN) :
  1. Circuit Switch Domain :A permanent channel for the duration of the call.
  • MSC(Mobile Switching Centre) :it manage the circuit switched calls under way.
  • GMSC(Gateway Mobile Switching Centre) :Responsible for obtaining the location of subscriber, so that calls from other external networks can be delivered correctly. In practice, the GMSC is just a function that can be part of a MSC.
      2.Packet Switch Domain :This Domain was designed to carry packet data.

       i>SGSN(Serving GPRS Support Node) :The SGSN provided a number of functions within the                   UMTS network architecture.
  • Mobility management   When a UE attached to the Packet Switched domain of the UMTS Core Network, the SGSN generates MM information based on the mobile's current location.
  • Session management:   The SGSN managed the data sessions providing the required quality of service and it also managed what were termed the PDP (Packet data Protocol) contexts, i.e. the pipes over which the data was sent.
  • Interaction with other areas of the network:   The SGSN was able to manage its elements within the network only by communicating with other areas of the network, e.g. MSC and other circuit switched areas.
  • Billing:   The SGSN was also responsible billing. It achieved this by monitoring the flow of user data across the GPRS network. CDRs (Call Detail Records) were generated by the SGSN before being transferred to the charging entities (Charging Gateway Function, CGF).
        ii>GGSN(Gateway GPRS Support Node) :It handled inter-working between the UMTS packet switched network and external packet switched networks, and could be considered as a very sophisticated router. In operation, when the GGSN received data addressed to a specific user, it checked if the user was active and then forwarded the data to the SGSN serving the particular UE.
    

Comments

Post a Comment

Popular posts from this blog

Accessibility KPI

Image
  Accessibility  :If A UE Requested for the some services to the system and System will Response UE Properly, It means Accessibility is  completed successfully. Accessibility KPIs are used to measure how successfully user is able to access the Network. Divided in 3 segments. RRC Phase S1 Signaling Phase E-RAB Phase In the Call Flow System, after the RACH Procedure,2nd Procedure comes the RRC Phase. RRC Rejection due to Congestion: May be the Reason eNB will be busy or it is very congested, It don't have Resources, So that it can allow new user.                                                How we can Reduce the Congestion Decrease the UE Inactive Timer to a smaller value( If we reduce this timer, UE will less stay in RRC connected mode, more offen release by enb) . This will initiate early release for the users, Hence Load will be reduced. However this can increase the signaling load as idle user can try to come back to network more frequently which can increase CPU usage of the e
Read more

LTE Network Architecture

Image
  MME(Mobility Management Entity)  : Manages UE access network and mobility, as well as establishing the bearer path for UE's. It is responsible for selecting the S-GW for a UE at the initial join and at a time of intra- LTE Handover. S-GW(Serving Gateway)  : S-GW will act as Router, which will forward user data to P-GW. S-GW creates Bearer table. P-GW(Packet Data Network Gateway)  : Allocates QOS(Quality of service) to those Bearer table. Allocates the IP address to the UE. HSS(Home Subscriber Server)  : User's Subscription Profile will be stored in the HSS.MME will download the subscription profile from the HSS when any mobile will be Registered to the MME. PDN(Packet Data Network)  : PDN is the point with which user can communicate with outside world. 3 Types of PDN  : Internet Corporate VPN IMS DRB= Data Radio Bearer GTPU= GPRS Tunneling Protocol User Plane GTPC= GPRS Tunneling Protocol Control Plane
Read more

LTE Call Flow

Image
 User Equipment send the Random access preamble(Through RACH Channel) to eNodeB for Network access. eNodeB received the message and send the RA-Response with allotting a temporary identity named C-RNTI (Cell Radio Network Temporary Identity).   After receiving the RA-response from eNodeB, User Equipment send the request for RRC Connection(With Received C-RNTI) to eNodeB. eNodeB send the RRC Connection Setup to User Equipment.  After established the RRC Connection between eNodeB & User Equipment. User send the first NAS message for Attach to core Network(with IMSI) and PDN Connection Request. 5(ii) eNodeB forward this message to connected MME. MME look this message and send the IMSI to HSS for authentication. IMSI is already stored in HSS.HSS verify it and send the K,RAND and XRES to MME.6(ii) MME send the response given by HSS to User Equipment via eNodeB for authentication. After receiving the RAND value User Equipment compute value and find the result RES.RES value send to the MM
Read more