Modelling Radio over Fibre Link and Analysis using MATLAB

Learning outcomes for the assessment:

a) Comprehensive understanding of Radio over fibre concepts in communication systems

b) Ability to model a Radio over fibre link

c) Ability to critically analyse and evaluate performance of RoF systems

Task 1: Modelling fibre link and Analysis with different fibre lengths:

Task 2: Modelling Radio link, discussions and analysis:

Task 3: Discussion on emission guidelines and analysis

Task 4: Analyse comparing RoF and wireless links

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.

2 Objectives and Learning Outcomes

Main objectives of the assessment: To consider the operation of radio over fibre communication systems and its integration into wireless communications networks This assignment will contribute towards the following learning outcomes

1. Comprehensive understanding of Radio over fibre concepts in communication systems

2. Ability to model a Radio over fibre link

3. Ability to critically analyse and evaluate performance in RoF systems

4.1 System components:

The model can include the following subsystems that be accessed through double clicking on them and formulating the required parameters.

4.1.1 RF ASK modulator

This subsystem can receive two signals: A RF carrier and random data. In this system the default setting for random data rate is 1Gbps and RF carrier frequency is set as 32 GHz.

4.1.2 Laser diode

In this model a laser diode with constant default optical power of 10mW is considered.

4.1.3 MZM Electro-Optical Modulator

In Mach-Zehnder Modulator, a voltage applied to the electrical input (either the bias one or the modulating one) modifies the refractive index of the LiNbO3 substrate and leads to phase shift between light waves moving through different waveguides. A zero phase shift between the waves yields constructive recombination and thus maximum intensity at the output.

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:

i. Formulate the fibre link on the outline model and analyse the performance with different fibre lengthsfor 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.

ii. Identify the fibre length that gives a BER around 10-4. 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.

3) Task 2: Formulate a complete RoF model using the outline model and set the fibre length to (200 + 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 (providing a graph) and identify the separation that will give a BER around 10-3.

4) Task 3:

i. Discuss emission guidelines that need to be followed when using wireless schemes

ii. Analyse whether your computation in Task 2) iii. meets emissions requirements.

Compare the performance of a RoF link with 1400 + xx km fibre length and an all wireless link to analyse their performances. Details of the model employed with justifications and a BER vs communication link length plot is expected as part of this analysi