Interference Cancellation Detection Research Articles

Joint mode selection and resource allocation to flexibly guarantee quality of service for downlink MISO-NOMA systems

Non-orthogonal multiple access (NOMA) with successive interference cancellation (SIC) detection, knownas SIC NOMA, enjoys higher spectral efficiency (SE), but suffers increased processing complexity and additional error propagation compared to Non-SIC NOMA,in whichthe receivers directly detect their own signalsfrom thesuperposed signalwithout SIC detection. We propose a joint Mode Selection and Power Allocation (MSPA) scheme that can flexibly realize different kinds of tradeoffs while guaranteeing minimum rate requirements (MRRs) for two-user MISO-NOMA downlink. Specifically, we first obtain rate region boundaries that guarantee two users’ MRRs for two candidatemodes: maximum-ratio transmission (MRT)/SIC NOMA and minimum mean square error beamforming (MMSE-BF)/Non-SIC NOMA. We then construct an expression of power allocation factors (transmit power factors) that can satisfy the two users’ MRRs for MRT/SIC NOMA (MMSE-BF/Non-SIC NOMA) by introducing a parameter λ. Finally, we achieve outer boundary of the union ofthe two modes' rate regionsby mode selection and derive expected users' rates on it. Numerical results demonstrate that the proposed MSPA can improve SE and flexibly achieve different kinds of tradeoffs by adjusting λ, while guaranteeing the two users’ MRRs simultaneously for high signal to noise ratio (SNR) scenario and alternately guaranteeing the two users’ MRRs for low SNR scenario.

Minimizing energy consumption for NOMA multi-drone communications in automotive-industry 5.0

The forthcoming era of the automotive industry, known as Automotive-Industry 5.0, will leverage the latest advancements in 6G communications technology to enable reliable, computationally advanced, and energy-efficient exchange of data between diverse onboard sensors, drones and other vehicles. We propose a non-orthogonal multiple access (NOMA) multi-drone communications network in order to address the requirements of enormous connections, various quality of services (QoS), ultra-reliability, and low latency in upcoming sixth-generation (6G) drone communications. Through the use of a power optimization framework, one of our goals is to evaluate the energy efficiency of the system. In particular, we define a non-convex power optimization problem while considering the possibility of imperfect successive interference cancellation (SIC) detection. Therefore, the goal is to reduce the total energy consumption of NOMA drone communications while guaranteeing the lowest possible rate for wireless devices. We use a novel method based on iterative sequential quadratic programming (SQP) to get the best possible solution to the non-convex optimization problem so that we may move on to the next step and solve it. The standard OMA framework, the Karush–Kuhn–Tucker (KKT)-based NOMA framework, and the average power NOMA framework are compared with the newly proposed optimization framework. The results of the Monte Carlo simulation demonstrate the accuracy of our derivations. The results that have been presented also demonstrate that the optimization framework that has been proposed is superior to previous benchmark frameworks in terms of system-achievable energy efficiency.

Optimization design of RIS-assisted high-capacity visible light communications based on HDMA

In this paper, a new non-orthogonal multiple access (NOMA) scheme is proposed for the reconfigurable intelligent surface (RIS) assisted high-capacity visible light communication (VLC) system, which is named hybrid domain multiple access (HDMA). HDMA enjoys the benefit of hybrid-domain signals, including the power domain, code domain, and frequency domain, where the message passing algorithm (MPA) and successive interference cancellation (SIC) detectors are jointly used at the HDMA receiver. Furthermore, to achieve a higher communication capacity for the VLC system, we proposed an optimization model by jointly optimizing the power allocation ratio and RIS reflection units. The simulation results verified the proposed scheme. By comparing the system capacity of different RIS allocation schemes and multiple access methods, the VLC system based on HDMA proposed in this paper can significantly improve its communication capacity.

Joint design of ordered QR precoding and SIC detection for MIMO VLC systems.

Ordered successive interference cancellation (OSIC) detection has been investigated to mitigate the high spatial correlation for multiple-input multiple-output (MIMO) visible light communication (VLC) systems. However, existing OSIC schemes have to perform reordering and matrix inversion for each detected symbol, which may lead to high complexity when a large number of symbols are transmitted. In this work, a joint design of ordered QR decomposition precoding and SIC detection (OQR-SIC) is proposed for MIMO VLC systems. This work jointly investigates OQR precoding and SIC detection to reduce the detection complexity while alleviating spatial correlation issue for MIMO VLC systems. In OQR-SIC, with the upper triangular matrix obtained by QR decomposition, the SIC detector can detect the symbol sequentially without reordering and matrix inversion calculations. To improve the system data rate, we further optimize the ordering of the columns of the channel matrix before QR decomposition and the power allocation of transmitted signals under the constraints of dimming control, total electrical power and reliable SIC detection. Simulation results demonstrate that the proposed OQR-SIC achieves 2 dB and 9.8 dB signal-to-noise ratio gains compared to conventional QR-SIC in 4 × 4 and 9 × 9 MIMO VLC systems, respectively, when the bit error rate is 10-3.

BER performance analysis of asynchronous NOMA with arbitrary phase offset

An asynchronous transmission scenario for non-orthogonal multiple access (NOMA) user signals with arbitrary phase offset is investigated in this paper. To improve the system performance in the user power-balanced conditions, we adopt a synthetic detection method at the receiver, i.e., the jointly optimal maximal likelihood detection aided triangular successive interference cancellation (JO ML-TSIC) method. Analytical bit error rate (BER) solutions are obtained for a two-user case with the optimal, intentional one-half symbol period time delay implemented between the user signals. Furthermore, closed-form BER solutions for the case using the triangular successive interference cancellation (TSIC) detection method are also derived for comparisons. Numerical results show that the JO ML-TSIC receiver for the asynchronous system outperforms the TSIC receiver as well as the synchronous successive interference cancellation (SIC) receiver in all the conditions concerned. The results also show that the superiority of the JO ML-TSIC receiver is strengthened when the signals experience flat Rayleigh fading channels compared to the TSIC and the synchronous SIC receivers.

Low complexity ordered successive interference cancelation detection algorithm for uplink MIMO SC‐FDMA system

AbstractIn mobile communication, the most exploratory technology of fifth generation is massive multiple input multiple output (MIMO). The minimum mean square error and zero forcing based linear detectors are used in multiuser detection for MIMO single‐carrier frequency division multiple access (SC‐FDMA). When the received signal is detected and regularization sequence is joined in the equalization of spectral null amplification, these schemes experience an error performance and the signal detection assesses an inversion of a matrix computation that grows into complexity. Ordered successive interference cancelation (OSIC) detection is considered for MIMO SC‐FDMA, which uses a posteriori information to eradicate these problems in a realistic environment. To cancel the interference, sorting is preferred based on signal‐to‐noise ratio and log‐likelihood ratio. The distinctiveness of the methodology is to predict the symbol with the lowest error probability. The proposed work is compared with the existing methods, and simulation results prove that the defined algorithm outperforms conventional detection methods and accomplishes better performance with lower complication.

Uplink Performance of Cell-Free Massive MIMO With Multi-Antenna Users Over Jointly-Correlated Rayleigh Fading Channels

In this paper, we investigate a cell-free massive MIMO system with both access points (APs) and user equipments (UEs) equipped with multiple antennas over jointly-correlated Rayleigh fading channels. We study four uplink implementations, from fully centralized processing to fully distributed processing, and derive their achievable spectral efficiency (SE) expressions with minimum mean-squared error successive interference cancellation (MMSE-SIC) detectors and arbitrary combining schemes. Furthermore, the global and local MMSE combining schemes are derived based on full and local channel state information (CSI) obtained under pilot contamination, which can maximize the achievable SE for the fully centralized and distributed implementation, respectively. We study a two-layer decoding implementation with an arbitrary combining scheme in the first layer and optimal large-scale fading decoding (LSFD) in the second layer. Besides, we compute novel closed-form SE expressions for the two-layer decoding implementation with maximum ratio (MR) combining. In the numerical results, we compare the SE performance for different implementation levels, combining schemes, and channel models. It is important to note that increasing the number of antennas per UE may degrade the SE performance.

Performance analysis of least reliable symbol based ordered successive interference cancelation detection method for uplink NOMA

SummaryNonorthogonal multiple access (NOMA) is one of the key techniques to improve the spectral efficiency required for fifth‐generation (5G) mobile networks. A severe interuser interference is encountered during the detection process in the uplink NOMA scenario, leading to the imperfect successive interference cancelation (SIC), thereby resulting in extreme SIC error propagation. In this work, we propose a novel least‐reliable symbol‐based ordered‐successive interference cancelation (LRS‐OSIC) detection method for uplink NOMA to mitigate the severe effects of SIC error propagation. The bit error rate (BER) performance is presented for different phase‐shift keying (PSK) modulation schemes to better understand the proposed LRS‐OSIC algorithm. Further, detailed comparative analysis with the existing detection techniques for uplink NOMA is illustrated in terms of error rate and computation complexity. The obtained results prove that the proposed LRS‐OSIC detection method for uplink NOMA outperforms other existing techniques and closely matches the best achievable error performance as accomplished by the maximum likelihood (ML) decoder. Moreover, the simulation results are extended for three user scenarios to validate the benefits of the proposed LRS‐OSIC algorithm for more than two user scenarios.

An Analysis of the Error Rate Performance for Uplink Asynchronous Signal Detection in Non-Orthogonal Multiple Access

We investigate multiuser detection under uplink asynchronous scenario, where the triangular successive interference cancellation (T-SIC) detection scheme is exploited. As the existing analysis was conducted under some ideal assumptions for simplicity, the asynchronous scenario is analyzed under rigorous assumptions in this paper so that important insights are revealed for practical systems. Specifically, the average symbol error rate (SER) formulas are derived for a two-user system with arbitrary <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$M$ </tex-math></inline-formula> -ary quadrature amplitude modulation ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$M$ </tex-math></inline-formula> -QAM) over Rayleigh fading channels. These solutions are shown to have higher accuracies compared to the existing solutions. Furthermore, a novel iterative detection algorithm is proposed, i.e., the parallel T-SIC method, which is more efficient and effective compared to the iterative T-SIC method. Insightful discussion is conducted in terms of the potentials of the concerned iterative detection method. Simulation results show that the most significant improvement of the iterative detection reflects on the SER for the strongest user, and the reduction is always within 50% of the SER compared to the primary detection. The gains obtained by the iterative detection is negligible for higher order <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$M$ </tex-math></inline-formula> -QAM cases.

Projected Kaczmarz successive interference cancellation detection

AbstractIn this article, the recently developed Kaczmarz successive interference cancellation (KSIC) detector is generalized to the nonlinear case; specifically, a projected SIC detection scheme is developed using the projected Kaczmarz iterative method. This novel detector enjoys improved performance with minimal additional computational complexity. The new detector is first presented and then its convergence analysis is detailed. After that, the computational complexity analysis of this detector is conducted and compared to that of the KSIC detector. Finally, extensive numerical simulations are conducted in different scenarios. Simulation results show that the proposed projected Kaczmarz SIC detector can achieve lower BER and can support more users in the system compared to the KSIC detector.

A layer-wise distribution analysis of the WLMMSE-SIC MIMO receiver for rectilinear or quasi-rectilinear signals

In this brief, we investigate the widely linear minimum mean square error (WLMMSE) successive interference cancellation (SIC) detector in multiple-input-multiple-output systems with rectilinear or quasi-rectilinear transmit signals. To this end, layer-wise approximate probability density functions (PDFs) of the post-detection signal-to-interference-plus-noise ratio are first derived. It is next shown that the so-derived PDFs enable explicit and concise performance evaluations in terms of the symbol error rate and the outage probability. For rigor, both the cases with and without inter-layer error propagation are addressed, and closed-form solutions are provided. Validity of theoretical analysis is demonstrated via Monte Carlo simulations.

Application of an Interference Cancellation Detector in a Two-Way Relaying System with Physical Network Coding

In this paper, we investigate the performance of a detector recently proposed by us that is applied in the relay station receiving signals from two terminals concurrently exchanging data in the two-way relaying system. This is one of the potential configurations to save resources in fifth-generation systems, similar to non-orthogonal multiple access, which is also considered for such systems. Two-way relaying can be implemented using physical network coding. This technique originates from the network coding idea, in which network nodes can perform some mathematical operations. The idea of the investigated detector lies in the application of tentative decisions about weaker signals in the detection of stronger ones and then, after improved detection of stronger user signals, achieving more reliable decisions about the weaker ones. We compare the performance of the proposed detector with the performance of a detector in which the relay makes decisions on the data symbols received from the stations participating in two-way relaying on a symbol-by-symbol basis. Simulation results performed for two-way relaying with physical network coding reported in this paper confirm the superiority of the proposed detector when compared with the standard physical network coding solution applied in the relay node.

Hybrid MAP and PIC Detection for OTFS Modulation

Orthogonal time frequency space (OTFS) modulation has attracted substantial attention recently due to its great potential of providing reliable communications in high-mobility scenarios. In this article, we propose a novel hybrid signal detection algorithm for OTFS modulation. Based on the system model, we first derive the near-optimal <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">symbol-wise</i> maximum <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a posteriori</i> (MAP) detection algorithm for OTFS modulation. Then, in order to reduce the detection complexity, we propose a partitioning rule that separates the related received symbols into two subsets for detecting each transmitted symbol, according to the corresponding path gains. According to the partitioning rule, we design the hybrid detection algorithm to exploit the power discrepancy of each subset, where the MAP detection is applied to the subset with larger channel gains, while the parallel interference cancellation (PIC) detection is applied to the subset with smaller channel gains. We also provide the error performance analysis of the proposed hybrid detection algorithm. Simulation results show that the proposed hybrid detection algorithm can not only approach the performance of the near-optimal <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">symbol-wise</i> MAP algorithms, but also offer a substantial performance gain compared with existing algorithms.

LDM-Ex-FDM: A Novel Multi-Service Transmission Scheme for the ATSC 3.0 System

In order to improve system coverage performance, in this paper, a multi-service transmission scheme on the basis of the puncturing technique, namely layered division multiplexing extension frequency-division multiplexing (LDM-Ex-FDM), is proposed. The key idea of the proposed scheme is that the symbols punctured from the enhanced layer (EL) of fixed services will be independently transmitted on a certain number of subcarriers orthogonal to the LDM signal of the core layer (CL) and most of the EL. By doing so, the punctured symbols will be demodulated with a higher signal-to-noise ratio (SNR) on the receiver side and can be recovered well, thus improving the reception performance of the EL fixed services. Moreover, two puncturing strategies based on bit-interleaved coded modulation (BICM) symbols of the LDM-Ex-FDM scheme, namely equal interval symbol puncturing (EISP) and non-equal interval symbol puncturing (NEISP), are developed to improve the performance of the EL services. Simulation results are given to show that, when the puncturing rate in the LDM-Ex-FDM scheme is configured as 1/12, the performance of the fixed service can be improved by 1.8 dB, meanwhile the bit error rate (BER) performance of the mobile service is not affected. Thus, the overall system coverage performance can be improved. Furthermore, to reduce the computational complexity and the demodulation delay of fixed service carried in the EL, at the receiver, a direct interference cancellation (DIC) detector is proposed as well. Simulation results are given to show that, under high injection level and high modulation order, the proposed DIC scheme is able to achieve almost the same BER performance as that of the traditional successive interference cancellation (SIC) scheme while with lower computational complexity.

On the performance of ECF-based multi-threshold receiver in NOMA systems for vehicular communications with unknown impulsive noise

In this paper, we derive an analytical expression for the bit error probability of a multi-threshold (MTh) detector in the downlink three-user non-orthogonal multiple access (NOMA) based vehicular communication system with unknown noise. The MTh detector directly detects the signal of vehicle user with the highest channel gain without detecting the signals of weaker users and removing their effects. It is shown that the bit error probability performance of the MTh detector is superior to that of the successive interference cancellation (SIC) detector in a special case. Then, we propose a blind empirical characteristic function (ECF) based method to estimate the signal levels of vehicle users, required to implement the MTh detector, in unknown noise. Next, we derive an analytical expression for the variance of the proposed ECF-based estimator which is validated via computer simulations. It is shown that the ECF-based estimator is asymptotically unbiased and consistent. Furthermore, we obtain the normalized Cramér-Rao lower bound (NCRLB) for the estimators of signal levels which shows that the ECF-based estimator is almost efficient in small generalized signal-to-noise ratio (GSNR) values. Numerical results show that the ECF-based MTh detector outperforms the absolute median-based SIC detector in the mixture of Gaussian and α-stable noise.

A Novel Downlink IM-NOMA Scheme

In the next generations of communication systems, resources' scarcity devolves to a more critical point as a consequence of the expected massive number of users to be served. Furthermore, the users' contradicting requirements on quality of service forces the network to behave in a dynamic way in terms of the multiple access orchestration and resource assignment between users. Hence, the linear relation between the number of served users and the required (orthogonal or semi-orthogonal) resources in the orthogonal multiple access (OMA) schemes is no longer sufficient. As promising candidates, Non-orthogonal multiple access (NOMA) schemes and index modulation (IM) techniques are emerging to satisfy the ever-increasing connectivity demands and spectral efficiency. In this article, a novel IM-based NOMA downlink scheme, termed as IM-NOMA, is proposed, where the base station (BS) selects a channel or more to serve each user based on the IM concept and the corresponding power level is allocated based on the NOMA concept. At the users' ends, maximum likelihood and successive interference cancellation (SIC) detection methods are considered and their error rate, outage probability and computational complexity are studied. Simulation results confirm the advantage of the proposed IM-NOMA scheme and that it can outperform the conventional NOMA system.

Performance improvement of space diversity technique using space time block coding for time varying channels in wireless environment

Performance improvement of space diversity technique using space time block coding for time varying channels in wireless environment

Performance of OQAM/GFDM in Spatial Multiplexing MIMO Systems

Generalized frequency division multiplexing (GFDM) is a prominent candidate to be used by the mobile Fifth Generation (5G) physical layer. Nevertheless, the integration of GFDM with Spatial Multiplexing (SM) MIMO system is essential to fulfill the data rate requirements. SM detection of MIMO-GFDM becomes a more challenging topic because of ICI and ISI due to the non-orthogonal nature of GFDM, along with IAI. In this article, the authors propose a system that combines the Offset-Quadrature Amplitude Modulation (OQAM) with GFDM to mitigate self-induced interference, by using a simple Matched Filter (MF) detector and minimum additional processing at the receiver. Simulation results show a considerable achieved improvement in BER by the proposed OQAM/GFDM compared to QAM/GFDM when using MMSE-based Ordered Successive Interference Cancellation (OSIC) detector. Furthermore, this system is unaffected by the roll-off factor variations of used pulse-shaping filters.

Outage Analysis of Parasitic Ambient Backscatter Communication in Decode-and-Forward Relay Networks with SWIPT

In this paper, we investigate the outage performance of simultaneous wireless information and power transfer (SWIPT) based Decode-and-Forward (DF) relay networks, where the relay needs to simultaneously forward information for two relaying links, primary relaying link and parasitic relaying link. The primary relaying link is the traditional source-relay-destination relay system. While in the parasitic relaying link, the parasitic source, i.e., Internet-of-Things (IoT) tag, is not connected to the stable power source and thus has to backscatter the signals from the primary source to convey its information. The relay not only harvests energy from Radio Frequency (RF) signals from both sources but also forwards messages to their corresponding destinations. The primary source and destination are unaware of the parasitic backscatter transmission, but the relay and parasitic destination can employ successive interference cancellation (SIC) detector to eliminate the interference from the primary link and detect the message from the parasitic source. In order to investigate the interplay between the primary and parasitic relaying links, the outage probabilities of both relaying links are derived. Besides, the effects of system parameters, i.e., power splitting coefficient, forwarding power allocation coefficient and backscatter reflection coefficient, on the system performance are discussed. Simulation results verify our theoretical analysis. In the meanwhile, it is revealed that the advised relaying system has far larger sum throughput than the one with only primary relaying link and the parasitic relaying link can gain considerable throughput at the cost of negligible degradation of primary throughput.

Discrete Fourier Transform-Based Block Faster-Than- Nyquist Transmission for 5G Wireless Communications

Faster-than-Nyquist (FTN) signaling is regarded as a potential candidate for improving data rate and spectral efficiency of 5G new radio (NR). However, complex detectors have to be utilized to eliminate the inter symbol interference (ISI) introduced by time-domain packing and the inter carrier interference (ICI) introduced by frequency-domain packing. Thus, the exploration of low complexity transceiver schemes and detectors is of great importance. In this paper, we consider a discrete Fourier transform (DFT) block transmission for multi-carrier FTN signaling, i.e., DBT-MC-FTN. With the aid of DFTs/IDFTs and frequency domain windowing, time- and frequency domain packing can be implemented flexibly and efficiently. At the receiver, the inherent ISI and ICI can be canceled via a soft successive interference cancellation (SIC) detector. The effectiveness of the detector is verified by the simulation over the additive white Gaussian noise channel and the fading channel. Furthermore, based on the characteristics of the efficient architecture of DFT-MC-FTN, two pilot-aided channel estimation schemes, i.e., time-division-multiplexing DBT-MC-FTN symbol-level pilot, and frequency-division-multiplexing subcarrier-level pilot within the DBT-MC-FTN symbol, respectively, are also derived. Numerical results show that the proposed channel estimation schemes can achieve high channel estimation accuracy.