Shannon-limit approached information reconciliation for quantum key distribution

Information reconciliation (IR) corrects the errors in sifted keys and ensures the correctness of quantum key distribution (QKD) systems. Polar codes-based IR schemes can achieve high reconciliation efficiency; however, the incidental high frame error rate decreases the secure key rate of QKD systems. In this article, we propose a Shannon-limit approached (SLA) IR scheme, which mainly contains two phases: the forward reconciliation phase and the acknowledgment reconciliation phase. In the forward reconciliation phase, the sifted key is divided into sub-blocks and performed with the improved block checked successive cancellation list decoder of polar codes. Afterward, only the failure corrected sub-blocks perform the additional acknowledgment reconciliation phase, which decreases the frame error rate of the SLA IR scheme. The experimental results show that the overall failure probability of SLA IR scheme is decreased to $$10^{-8}$$ 10 - 8 and the efficiency is improved to 1.091 with the IR block length of 128 Mb. Furthermore, the efficiency of the proposed SLA IR scheme is 1.055, approached to Shannon limit, when the quantum bit error rate is 0.02 and the input scale of 1 Gb, which is hundred times larger than the state-of-the-art implemented polar codes-based IR schemes.

Implementation of an Adaptive MIMO System using Effective Minimization of Frame Error Rate

Paper Multiple Input Multiple Output (MIMO) is a technique which is now being widely used for wireless communication techniques such as 4G LTE. MIMO uses multiple antennas at the transmitter as well as at the receiver side in order to improve spectral efficiency although it increases the system complexity. Multipath propagation, which is the drawback for wireless communication, is used as an advantage in MIMO. This paper presents a model of Adaptive MIMO system in Simulink. The system adapts to specific transmit and receive diversity depending on the frame error rate. The proposed system uses 4 transmitting and receiving antennas, the number of antennas change as per the adaptation algorithm. The data is sent in the form of frames with each frame carrying the desired number of bits. Here, we have implemented the Orthogonal Space-Time Block Coding (OSTBC) scheme in a MATLAB Simulink model and implemented an adaptive algorithm to change the quantity of transmitting and receiving antennas depending on the frame error rate (FER) value.

An Effective Speaker Clustering Method using UBM and Ultra-Short Training Utterances

The same speech sounds (phones) produced by different speakers can sometimes exhibit significant differences. Therefore, it is essential to use algorithms compensating these differences in ASR systems. Speaker clustering is an attractive solution to the compensation problem, as it does not require long utterances or high computational effort at the recognition stage. The report proposes a clustering method based solely on adaptation of UBM model weights. This solution has turned out to be effective even when using a very short utterance. The obtained improvement of frame recognition quality measured by means of frame error rate is over 5%. It is noteworthy that this improvement concerns all vowels, even though the clustering discussed in this report was based only on the phoneme a. This indicates a strong correlation between the articulation of different vowels, which is probably related to the size of the vocal tract.