TIMED SIGNAL CONSTRUCTIONS AS A TOOL FOR INCREASING THE NUMBER OF CODEWORDS BY IMPLEMENTING THEIR CONSTANT LENGTH

It is indicated that due to changes in the restrictions on the duration of the basic element, which is the basis for the construction of the signal structure, an increase in the channel capacity was obtained by reducing the energy distance between the signal structures. In this case, the information parameter in these structures is not the parameters of the current or voltage, but the time. The work uses timer signal structures, which are synthesized, as well as positional signals from segments not less than the Nyquist element, but not multiples of it. It is this principle of formation that significantly increases the number of synthesized code structures in comparison with positional coding. It is noted that the information content of any event is determined by the number of its states, and the entropy and the probability of the occurrence of a particular event are interrelated values. In addition, timer signaling constructs allow synthesizing ensembles with a large information content in comparison with positional coding. Keywords: basic element, Nyquist element, information parameter, entropy, probability of occurrence, information segment, message, timer signal structure.

Improved blind demixing methods for recovering dense neuronal morphology from barcode imaging data

Cellular barcoding methods offer the exciting possibility of 'infinite-pseudocolor' anatomical reconstruction --- i.e., assigning each neuron its own random unique barcoded 'pseudocolor,' and then using these pseudocolors to trace the microanatomy of each neuron. Here we use simulations, based on densely-reconstructed electron microscopy microanatomy, with signal structure matched to real barcoding data, to quantify the feasibility of this procedure. We develop a new blind demixing approach to recover the barcodes that label each neuron. We also develop a neural network which uses these barcodes to reconstruct the neuronal morphology from the observed fluorescence imaging data, 'connecting the dots' between discontiguous amplicon signals.

An Optimized Vector Tracking Architecture for Pseudo-Random Pulsing CDMA Signals

The vector tracking loop (VTL) has high tracking accuracy and a superior ability to track weak signals in GNSS. However, traditional VTL architecture is established on continuous Code Division Multiple Access (CDMA) signal and is incompatible with pseudolite positioning systems (PLPS) because PLPS generally adopts a pseudo-random pulsing CDMA signal structure to mitigate the near-far effect. Therefore, this paper proposes an optimized VTL architecture for pseudo-random pulsing CDMA signals. To avoid estimation biases in PLPS, the proposed VTL adopts irregular update periods (IUP) pre-filters which adjust the update cycles according to the active timeslot intervals. Meanwhile, as the active timeslots of different pseudolites do not overlap, the sampling time of the navigation filter inputs is inconsistent and time-varying, causing jitter degradation. Thus, the proposed VTL predicts the measurements so that they can be sampled at the same time, which improves tracking accuracy. Simulation is carried out to evaluate the performance of the proposed VTL. The results suggest that the proposed VTL outperforms the traditional pre-filter-based VTL and IUP pre-filter-based VTL.

Binary phase hopping based spreading code authentication technique

Civil receivers of Global Navigation Satellite System (GNSS) are vulnerable to spoofing and jamming attacks due to their signal structures. The Spreading Code Authentication (SCA) technique is one of the GNSS message encryption identity authentication techniques. Its robustness and complexity are in between Navigation Message Authentication (NMA) and Navigation Message Encryption (NME)/Spreading Code Encryption (SCE). A commonly used spreading code authentication technique inserts unpredictable chips into the public spreading code. This method changes the signal structure, degrades the correlation of the spreading code, and causes performance loss. This paper proposes a binary phase hopping based spreading code authentication technique, which can achieve identity authentication without changing the existing signal structure. Analysis shows that this method can reduce the performance loss of the original signal and has good compatibility with the existing receiver architecture.