COMMUNICATION SYSTEMS

COMMUNICATION SYSTEMS

  • Cloud Optical Access Networks for virtualized GNSS receivers (GLIGHT)

The invention consists of a (set of) GNSS receiver defined by software, executing in the cloud and receiving a continuous flow of GNSS signals captured by a (set of) dumb radiohead located elsewhere, and connected to the cloud via a high-performance communication network. The proposed system architecture allows for continuous GNSS signal streaming from the antenna to the GNSS baseband unit, in addition to any arbitrary duty cycling required by a certain application or service. By combining Optical Network technology and the End-to-end Network Function Virtualization management and orchestration (NFV-MANO) approach, the proposed invention enables the actual (and rapid) deployment of virtual services over software- defined optical networks that allow for the continuous transmission of GNSS signals from the antenna to a remote baseband processor. The possibilities of such a system architecture are enormous. For instance, one could envisage the rapid deployment of a set of low-cost radioheads sending raw GNSS signals to a software-defined receiver in the cloud, and thus acting as a network of GNSS reference stations, generating high-rate pseudorange, phase and Doppler observables at real-time, and interesting products such as differential data to provide high-accuracy services to third users.

  • Equalization of time-varying in channels OFDM systems

The OFDM modulation is very robust against the frequency selective nature of the channel, leveraging the use of the cyclic prefix to compensate for the effect of the multipath channel. On the other hand, OFDM systems are particularly sensitive to the time variations of the channel. These scenarios may arise in typical 5G case studies such as high-speed trains or uplink multi-user MIMO where the signals coming from each user may be impacted by severe carrier frequency offsets. Current OFDM equalization solutions for highly time varying scenarios are extremely complex and typically based on iterative schemes that operate on both time and frequency domain of the signal. This high complexity has motivated the use of other simpler waveforms (such as single carrier modulations) in high Doppler/mobility scenarios, e.g. in satellite links. The invention presented here consists in a simple equalization scheme that can overcome the detrimental effects of severe time selectivity in OFDM modulations. The main advantage of the proposed scheme is its low complexity and simplicity of implementation, which is in stark contrast with currently proposed solutions for this type of scenarios. The implementation turns out to be especially suitable in situations with multiple users/antennas subject to different Doppler effects.

  • Simplified Equalization of OFDM Waveforms with Insufficient Cyclic Prefix

The need for low latency communications has motivated the introduction of OFDMnumerologies with large frequency subcarrier separation in order to shrink the durationof the multicarrier symbol. However, shrinking the duration of the OFDM symbolimplies shortening Cyclic Prefix (CP), which may often become insufficient to span thewhole channel duration. A simple equalization strategy for OFDMwaveforms is proposed that specifically targets this difficult scenario.

Specifically, the novel equalization strategy aims at cancelling the interference (both inter-symbol and inter-carrier) impinging on the OFDM symbol in the short-CP scenario, which has recently been expressed in closed form. The proposed architecture canbe very efficiently implemented in the frequency domain without the need forcomplex matrix inversions or iterative estimation procedures. Furthermore, the equalizer is shown to outperform conventional methodologies as the system dimensions grow large.

  •  Flexiband RF software driver

A software driver that allows using Fraunhoffer’s FLEXIBAND RF front-end with our open source software GNSS-SDR.

  • IP cores for GNSS signal generation

Generation of GNSS signals with custom parameters from an embedded device.

  • IP cores for embedded GNSS-SDR

GNSS-SDR is a software-defined Global Navigation Satellite System (GNSS) receiver. When executed in a regular computer, the computational load limits its real-time execution to simple receiver configurations, but not in complex setups (i.e., multi-band, multi-constellation GNSS receivers) a regular computer cannot reach real-time. By performing FPGA off-loading in a SoC (a single IC containing ARM+FPG processors), the software-defined receiver is able to attain real-time in advanced receiver configurations, in an embedded device.

  • Hardware platform for GNSS-SDR

Combine in a single platform a RF front-end, a commercial GNSS receiver and the processing capabilities to experiment with GNSS-SDR applied to signals not covered by the commercial GNSS receiver.

  • TIMON – Sensor Fusion Position

TIMON is a low-cost high accurate positioning device implementing a sensor fusion algorithm based on hybrid technologies that integrates GNSS (Global Navigation Satellite Systems) and INS (Inertial Navigation Systems) with high precision radio ranging/positioning technology such as UWB (communication and positioning system based on impulse radio waveforms of very short pulse time duration). TIMON is both a hardware prototype and an experimental platform to evaluate sensor fusion algorithms for positioning and navigation. It can be used to evaluate advanced algorithms in postprocessing or real-time mode. TIMON also includes a series of data fusion algorithms based on loosely, tightly and hybrid coupled schemes. That is, data fusion algorithms spanning from standalone 3D positioning estimates to fusion of ranging estimates from different sources. The core of the data fusion algorithm is based on INS/GNSS integration, augmented with technology agnostic ranging measurements. Available implementation includes additional sensors such as odometers and magnetometers. TIMON framework is supported by TIMON Graphical User Interface for real-time vehicle monitoring and parameter tracking over digital open-source maps.