UMTS WCDMA Radio Access Network

Interactive Virtual Laboratory for 3G Mobile Communications

Experiment Objectives

Experiment 1: UTRAN Architecture

  • Understand the three-layer UMTS network architecture (UE, UTRAN, Core Network)
  • Identify the functions of NodeB and RNC in the UTRAN
  • Trace the flow of data from UE to Core Network through UTRAN interfaces
  • Observe the Iub and Iu interfaces and their protocols

Theoretical Background

UTRAN (UMTS Terrestrial Radio Access Network)

The UTRAN consists of two main elements:

  • NodeB (Base Station): Handles physical layer processing, radio transmission/reception, and basic radio resource management. It connects to the RNC via the Iub interface.
  • RNC (Radio Network Controller): Controls radio resources, manages handovers, and handles MAC/RLC layers. It connects to the Core Network via the Iu interface.

The Uu interface connects the UE to NodeB, while Iur interface connects different RNCs for soft handover support.

Experimental Procedure

  1. Study the network diagram showing UE, NodeB, RNC, and Core Network elements
  2. Click on each network element to view its specifications and functions
  3. Initiate a connection request from the UE
  4. Observe the signaling flow through NodeB to RNC
  5. Monitor the establishment of radio bearers
  6. Record the latency and throughput metrics at each interface
  7. Analyze the protocol stack at each interface (PHY, MAC, RLC, RRC)

Interactive Simulation

UE: Idle
NodeB: Standby
RNC: Standby
📱
UE
User Equipment
📡
NodeB
Base Station
🖥️
RNC
Radio Network Controller

Connection Control

--
Round Trip Time
ms
--
Data Rate
kbps
--
Tx Power
dBm
--
Ec/Io
dB

Lab Report Guidelines

Required Report Sections

  1. Aim: State the objective of the experiment
  2. Equipment: Virtual lab components used
  3. Theory: Brief description of relevant concepts
  4. Procedure: Steps followed during simulation
  5. Observations: Screenshots and data collected
  6. Calculations: Any mathematical analysis performed
  7. Results: Tabulated findings
  8. Conclusion: Summary of learnings
  9. Questions: Answers to post-lab questions

Post-Lab Questions

  1. Explain the role of Iub interface in UTRAN architecture.
  2. Calculate the processing gain for SF=128. What is the corresponding data rate?
  3. Why is fast power control essential in WCDMA systems?
  4. Compare soft handover and hard handover. What are the advantages of soft handover?
  5. Explain why OVSF codes with SF=4 cannot be used if SF=8 code C8,4 is already allocated.

Submission

Prepare your report in PDF format including:

  • Student Name and ID
  • Course: Mobile Communications
  • Experiment Date
  • All observation tables with data
  • Graphs and screenshots from simulations