EE5550 - Radio and Optical Communication Systems - Brunel University London
Learning outcome 1: Comprehensive understanding of Radio over fibre concepts in communication systems
Learning outcome 2: Ability to model a Radio over fibre link
Learning outcome 3: Ability to critically analyse and evaluate performance in RoF systems
Learning outcome 4: Awareness of regulatory requirements related to RF emissions.
Modelling and Analysis of a Radio over Fibre Link
Introduction
Optical and wireless access network infrastructure is widely deployed around the world. When heterogeneous access networks converge to a highly integrated network via a common optical feeder network, network operators can lower the operating costs of their access networks and meet the capital costs of future network upgrades more easily. In addition, the converged access network facilitates greater sharing of network infrastructure between multiple network operators. In such a scenario of convergence, the transportation of radio signals over optical fibre links would be a way of simplifying the architecture of remote BSs.
In this assignment, a radio over fibre link and a RF link will be modelled and analysed using MATLAB. Simulink will be used to model the link.
Tasks for the assignment
An outline radio over fibre Simulink model "RoF_Assignement.slx" is available on BLACKBOARD and can be downloaded and saved to the "H" drive. This model can be accessed by first stating the MATLAB software and using the "open" option. Required models can be formulated by double clicking the sub systems. This model can generate a random data stream and the input and output data can be compared to see the Bit Error Rate. Some default parameters are defined in the Simulink environment under:
File → Model Properties → Model Properties → "Callbacks" tab → Initfcn
dataR = 1e9; % Symbol rate/Data Rate
Nsample = 50; % Number of samples per symbol
SPeriod = 1/dataR; % Symbol period
Stime = 1/dataR/Nsample; % Sample time for simulation
Delay = 4; % Delay caused by the filters (2 filters)
f_loss = -0.0071; % Fibre loss, alpha /km
The simulation time can be set using the entry box below the main menu and simulations can be run using the "green run" button on the Simulink environment. Time domain plots can be obtained by double clicking the scope symbols and using the auto scale function on the top button menu.
The following tasks need to be completed for this assignment
1) Discuss benefits of radio over fibre in modern communication networks as part of the introduction to this assignment report.
2) Task 1: Formulate the fibre link on the outline model and analyse the performance with different fibre lengths for a fibre loss, alpha of -0.00xx; (xx: last two digits of your student number). Details of the model employed and a BER vs fibre length plot is expected as part of this analysis.
Please remember that you need to run the simulation for sufficient duration to obtain better accuracy. For example, for a BER of around 10-5 the model needs to be run long enough to obtain at least 105 data bits. Also use a better resolution for the distance (distance step) when carrying out this analysis.
3) Task 2: Formulate the radio link on the outline model and set the fibre length to 100 + xx km (xx: last two digits of your student number).
i. Provide details of the model introduced.
ii. Discuss the effects on data signal when it travels through the model sub systems giving appropriate scope displays and identify the assumptions made in this model.
iii. Analyse the performance for different transmitter and receiver separations and identify the separation that will give a BER around 10-4.
iv. Critically discuss techniques that can be employed to increase the separation distance on the RF link.
4) Task 3: Discuss emission guidelines that need to be followed when using wireless schemes and analyse whether your computation in Task 2) iii. meets emissions requirements.
5) Task 4: Formulate a direct intensity modulated RoF scheme and compare its performance with the model in task 2. Details of the model employed with justifications and a BER vs fibre length plot is expected as part of this analysis.
Attachment:- Radio and Optical Communication Systems.rar