Bit Error Rate Loss Research Articles

Low-Complexity MMSE Receiver Design for Massive MIMO OTFS Systems

We design a low-complexity minimum mean square error (MMSE) receiver for a practical rectangular pulse-shaped orthogonal time frequency space (OTFS) massive multiple-input multiple-output (mMIMO) system. The proposed receiver is designed by exploiting the OTFS channel sparsity, and the structure of matrices involved in the MMSE receiver. We show that the sparse OTFS channel matrix is multi-banded, and has a high bandwidth. This is because its non-zero elements, which occur in multiple bands, are scattered throughout the matrix. We reduce its bandwidth by using the Reverse Cuthill-Mckee algorithm. The proposed MMSE receiver does not use any approximation, and thus has the same bit error rate (BER) as that of its conventional counterpart. We show that the proposed receiver, without any BER loss, achieves significantly lower complexity than the existing state-of-the-art receivers.

Multi-task deep learning based hybrid precoding for mmWave massive MIMO system

Due to the different signal-to-noise ratio (SNR) of each subchannel, the bit error rate (BER) of hybrid precoding based on singular value decomposition (SVD) decreases. In this paper, we propose a multi-task learning based precoding network (PN) model to solve the BER loss problem caused by SVD based hybrid precoding under imperfect channel state information (CSI). Specifically, we firstly generate a dataset including imcomplete CSI input channel matrix and corresponding output labels to train the PN model. The output labels are designed based on uniform channel decomposition (UCD) which decomposes the channel into multiple subchannels with same gain, while the vertical-bell layered space-time structure (V-BLAST) signal processing technology is combined to eliminate the inner interference of the subchannels. Then, the PN model is trained to design the analog and digital precoding/combining matrix simultaneous. Simulation results show that the proposed scheme has only negligible gap in spectrum efficiency compared with the fully digital precoding, while achieves better BER performance than SVD based hybrid precoding.

Coded modulation faster-than-Nyquist transmission with precoder and channel shortening optimization

Faster-than-Nyquist (FTN) signaling can improve the spectrum efficiency (SE) of the transmission system. In this paper, we propose a coded modulation FTN (CM-FTN) transmission scheme with precoder and channel shortening (CS) optimization to improve bit error rate (BER) performance and reduce the complexity of FTN equalizer. In our proposal, the information rate (IR) or spectral efficiency (SE) is employed and verified as a better performance metric for CM-FTN than the minimum Euclidian distance (MED). The precoder of CM-FTN is optimized for maximizing the IR criterion using the bare-bones particle swarm optimization (BB-PSO) algorithm. Further, a three-carrier CM-FTN system model is used to capture the broadening effect of precoder. Also targeting for the IR maximization, the inter-symbol interference (ISI) length for CS is optimized to reduce the receiver complexity without performance loss. Simulation results demonstrate that our method has a 0.6dB precoding gain compared with the non-precoding scheme and a maximum of 87.5% of the complexity of FTN equalizer is reduced without BER loss.

Bit and Packet Error Rate evaluations for Half-Cycle stage cooperation on 6G wireless networks

The excellent features of the sixth generation (6G) of wireless technology enthuses researchers to apply advanced and complex techniques on mobile communication networks, which is what this paper explores. As a result of the ability of 6G to exchange vast data rates and network programming, the Cooperative Network Coding (CoNC) technique can be implemented to improve the connectivity and diversity within 6G applications.Though CoNC is usually implemented at the second stage, this paper proposes dividing the first stage into two Half-Cycle stages, and then applying CoNC at the second Half-Cycle stage. The resulting Bit Error Rate (BER) behaviour is investigated on the physical layer for direct data exchange in 6G local mobile networks over an Additive White Gaussian Noise (AWGN) channel. Partial Unit Turbo Code (PUTC) (4,2,1,4) and (8,4,3,8) are used by each mobile node as the forward error correction technique, which means that each mobile acts as a Base Station (BS) for other mobiles in the local network by applying CoNC on the received packets, and then each mobile node (or BS), either Amplify-and-Forward (AF), or Decode-re-encode-amplify and Forward (DF), acts. When full connectivity is not achieved at the end of the first two Half-Cycle stages, new Half-Cycle stage transmissions follow, and the BER behaviour for all additional Half-Cycle stages is obtained. The results illustrate that applying CoNC at the second Half-Cycle stage of the first general stage produces a limited BER loss. To mitigate the damage in the BER, a soft-decision PUMTC decoder is also proposed.

Complementary peak reducing signals for TDCS PAPR reduction

Transform domain communication systems (TDCSs) are cognitive anti-interference multi-carrier communication systems with dynamic spectrum access. The inherent high peak-to-average power ratio (PAPR) of TDCS reduces the efficiency of the power amplifier. Adaptive waveform generation of the TDCS also causes the PAPR to vary according to the spectral conditions on hand. In this study, a complementary peak reducing signal (CPRS) method is proposed and analysed. It uses all unoccupied frequency bins to transmit data and uses all interfered frequency bins to generate CPRSs. Every data signal and its corresponding CPRS are orthogonal and complementary, so as to fully occupy all frequency bins. Therefore, the PAPR reduction of the composite signal with all frequency bins is considered. Once the optimal pseudo-random phase sequence is determined, the sequence can adapt to all spectral conditions without side information, and the computational complexity for diverse spectral conditions is greatly reduced. Moreover, the orthogonality between the data signal and its CPRS in the frequency domain eliminates distortions and spectral spreading. As a component of the transmitting signal, CPRS may cause bit error rate (BER) loss. This study also proposes a signal power adjustment mechanism to achieve a compromise between PAPR reduction and BER loss.

Joint Optimization of Constellation With Mapping Matrix for SCMA Codebook Design

Sparse code multiple access (SCMA) is being considered as a promising multiple access solution for 5G systems. A distinguishing feature of SCMA is that it combines the procedures of bit to constellation symbol mapping and subsequent spreading using multidimensional codebooks differentiated by users. Such codebooks dominate the system implementation as a main source of not only performance gain but also design complexity. This letter presents a joint constellation with mapping matrix design for SCMA codebooks, which formulates the constellations optimization as a nonconvex quadratically constrained quadratic programming problem based on a set of well-constructed mapping matrices. We elaborately solve the problem to achieve outperformance over existing SCMA design in terms of bit error rate (BER). For improving practicality, an approximate approach is further proposed to reduce the complexity significantly with a limited BER loss.

Bit errors due to channel modulation of media jitter

Recording media written-in transition jitter noise can limit magnetic recording systems. Read channel intersymbol interference (ISI) modulates media jitter in a head/disk/channel, attenuating jitter at low linear density due to classical ISI but amplifying at high density. This paper assesses whether jitter modulation is significant in typical disk drive peak detect (PD) and partial response (PR) channel design, where maximum linear bit density is sought at a specified bit error rate (BER). Experimental isolated pulse data, transition noise, and electronic noise measurements from a 65 mm head/disk recording design are used as inputs to a Matlab simulation of PD and PR Lorentzian channel low pass and boost filters, PD differentiator filter, PR digital filter, and PD/PR bit detectors. The goal of such models is optimizing the designable PD and PR channel parameters for realistic maximum linear density prediction. However their complexity obscures the jitter modulation contribution, which is demonstrated here by the shift in the EER versus density curves, when the jitter modulation is mathematically turned off. Jitter modulation is thereby shown to be significant but not dominant in (1,7) PD density limits. About an order of magnitude BER loss due to jitter modulation can occur at typical PD linear channel bit densities P/sub 50//T/spl ap/2. Jitter amplification in PD channels can occur at channel density 3.8 (above usable PD limits). PR channels only amplify media jitter, degrading EER by about an order of magnitude at typical (0, k) PR4 densities, and degrading timing channel accuracy twice as fast as channel density increases. Lorentzian isolated pulse (ISOP) modeling is compared to recording physics mathematical pulses, and simulation statistical validity checks are made.