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Títol: Power Efficiency Enhancement of Transmitters using Adaptive Envelope Tracking and Shaping Techniques for Small Payload Space Applications

Estudiants que han llegit aquest projecte:

Director/a: GILABERT PINAL, PERE LLUÍS

Departament: TSC

Títol: Power Efficiency Enhancement of Transmitters using Adaptive Envelope Tracking and Shaping Techniques for Small Payload Space Applications

Data inici oferta: 09-04-2015     Data finalització oferta: 09-12-2015


Estudis d'assignació del projecte:
    Tipus: Individual
     
    Lloc de realització: EETAC
     
    Segon director/a (UPC): MONTORO LÓPEZ, GABRIEL
     
    Paraules clau:
    envelope tracking, power amplifier, small satellites, shaping functions, power efficiency
     
    Descripció del contingut i pla d'activitats:
    With the rise of modular architecture and distributed satellite systems with multiple small payloads instead of conventional larger spacecrafts, the efficient characterization of power budget and available power constraints become even more vital. In order to establish high data rate downlink communications in small satellite applications, use of highly efficient, non-conventional power amplification techniques is going to be a key factor in future communication systems. The concept of having small, less power consuming and high data rate transmission system extends to vast number of applications like light weight Unmanned Aerial Vehicle (UAV) and hand-held communication modules etc.

    The idea is to study and develop an envelope tracking technique which should be able to dynamically supply the Radiofrequency power amplifier. Thus, not having a constant power supply to PA leads to less power consumption and a highly efficient transmission module which is the demand of systems with limited power budget. The amplifiers intended for such systems exhibit nonlinear behavior when it comes to operating at maximum output power and cause distortion in adjacent bands.
    Thanks to the shaping function block (placed before the Digital-to-Analog Converter (DAC) in the power supply chain of RF power amplifier), some simple linearization can be applied to the Envelop Tracking PA, while benefiting from the power efficiency improvement achieved thanks to the dynamic supply of the PA. By imposing an isogain trajectory trough the shaping function, we can optimize the available power for high data rate communications while keeping the intermodulation distortion at acceptable levels without introducing significant computational load.

    Master Thesis will comprise of developing the theoretical and functional understanding of small satellite communication applications and later implement an Envelop Tracking and Shaping Block to achieve the predefined efficiency results.
    • Understanding of behavior modeling of PA using Output and Input data (Piece-wise Spline interpolation)
    • Design the Shaping function to maximize linearity using Piece-wise Spline interpolation
    • Design an adaptive shaping function based in a simple LMS-based algorithm
    • Test the LMS LUT-based shaping function in a real envelope tracking PA test-bed.


     
    Overview (resum en anglès):
    This thesis discourses the need and methodology to enhance power efficiency of modern communication modules which range from handheld devices to small payload space applications. Over the years, performance of radio communication standards has been improved with the emergence next out of the box idea until the system saturates its resources such as available power and RF spectrum. Therefore, it is vital to achieve optimal resource utilization by exploiting the characteristics of key components like power amplifier.
    In a typical RF communication system, PA is the most power hungry component, and the fact that it also presents a non-linear behavior for different operating regions warrants thorough study. When it comes to PAE of modern communication standards (Wi-Fi, LTE), the conventional fixed supply PAs limit the system performance because for a rapidly varying input signal with high ‘Peak-to-Average Power Ratio’ (PAPR) values, a lot of power is wasted in amplifying signals with low input power. A significant drop in PAE from GSM (65 %) to LTE (30 %) highlights the challenge [1]. This objective of the thesis is to study techniques for improving PAE by and test an algorithm on a ‘Device-Under-Test’ (DUT) to understand how a more dynamic control over power supply to a PA offers improved resource utilization. The idea lends its applications to power constrained nanosatellites, where the need to use less power to transfer maximum amount of information is ever increasing.

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