ESA: Process for pilot-aided carrier phase synchronisation

Kurzfassung

An international organization has developed a process for providing a phase synchronization of a pilot aided carrier of an input digital signal. The proposed algorithms are envisaged to be particularly advantageous when operating with a high level of transmitter/receiver oscillator`s phase noise. This situation is typical of the consumer market where due to strong cost restrictions and for high frequency systems (Ku, Ka, Q band). Company is looking for a license agreement collaboration.

Details

The present invention refers to novel carrier synchronization techniques for RF digital transmissions. In particular, the proposed algorithms are envisaged to be particularly advantageous when operating with a high level of transmitter/receiver oscillator's phase noise.
Other pilot aided techniques are more effective but they are much complex and yet have to show a feasibility over wide signal-to-noise ratio ranges
Classical techniques for carrier phase recovery in the presence of a high strong phase noise are not effective as they are affected by both excessive jitter as well as cycle slips, especially for modulation formats with 8 and 16 points. In fact in these conditions the synchronizer undergoes a number of cycle slips in a relatively short time, and the phase jitter results to be in excess with respect the desired target. The proposed algorithms make use of regularly inserted pilot symbols with a total overhead around 2%. They provide a good carrier frequency and phase estimate with low jitter and no cycle slips. Furthermore, they are (at least for a set of the proposed algorithms) completely data modulation independent as they do not make any use of the transmit data. According to one of the proposed techniques, the carrier phase estimate is obtained by an optimum (in the minimum mean square error sense) interpolation of maximum likelihood pilot-based estimates, while the carrier frequency is obtained by holding the pilot-based estimates that are given by a simple delay-and-multiply PLL.
The synchronization schemes according to the present invention can also be advantageously applied to modulation formats that are difficult to synchronize as well as very sensitive to a carrier phase jitter as the non-linearity friendly 16-APSK and 32-APSK constellations. Also, the complexity of the proposed synchronizers is and does not require any synchronizer thus easing the demodulator operations.

Innovative Aspects:
The present invention refers to novel carrier synchronization techniques for RF digital transmissions. In particular, the proposed algorithms are envisaged to be particularly advantageous when operating with a high level of transmitter/receiver oscillator's phase noise.
Furthermore the proposed algorithms make use of only a small pilot tones overhead (around 2%), and its relative simple structure allows to contain the level of complexity of the system.