Interleaver Design Research Articles

Progressive pattern orthogonal interleaver set for interleave division multiple access based, non orthogonal multiple access schemes: Beyond 5G perspective

Abstract This communication suggests an orthogonal interleaver set for interleave division multiple access (IDMA) based non orthogonal multiple access (NOMA) schemes from beyond 5G viewpoint to support enormous increase in user count. The method generates an orthogonal interleaver set by providing two mother interleavers as seed to generate other users’ interleaving patterns progressively. The key feature of the proposed scheme is that it reduces implementation complexity and memory requirement at the base station, while implementing iterative multiuser detection (MUD), which most of the interlaever designs suggested in literature do not consider. It provides additional security to the user data due to progressively changing mother interleavers’ pattern along with the conventional purpose of providing unique identity for individual users in the system. The proposed orthogonal interleaver set is tested through simulations under multiple IDMA system configurations. It has been observed that it preserves the bit error rate (BER) performance of the IDMA scheme along with the optimal implementation complexity and minimal information exchange requirement between base station and mobile station to share the interleaver design.

Design of Chaotic Interleaver Based on Duffing Map for Turbo Code

This article presents the performance analysis and comparison of turbo codes for several interleavers with short blockchains. According to the symmetry concept, turbo codes consist of two symmetric convolutional codes preceded by an interleaver. Some interleavers can be described by symmetric 3 × 3 generator matrices, whereas others are represented through symmetric matrices in which the nonzero terms in the matrix are monomials. Interest in short blockchains has grown over the years because of their use in emerging applications that require the transmission of data units in the order of hundred bits. In this research, interleavers used are random interleaver, semi-random interleaver, quadratic polynomial permutation (QPP) interleaver, and chaotic Lozi map interleaver. For each interleaver, the turbo code is assessed with at least two short data distances; then, the interleavers are compared against each other. The performance of turbo codes is assessed based on bit error rate, particularly with lengths between 64 and 512 bits. Additionally, an interleaver based on Duffing chaotic maps is proposed, whose deterministic nature provides an advantage, and the performance results are presented, achieving excellent BER values for 64 bits. With these results, the effect of the interleaver on turbo codes and particularly on short block length interleavers, is studied.

Improved IDMA for Multiple Access of 5G

Due to its good performance and low complexity, IDMA is believed to be an important technique for future radio access (FRA). However, its performances are highly affected by the interleaver design. In this paper we propose two contributions to improve the performance of the IDMA. First, we propose a new interleaver design, called "NLM interleaver", which improves the computational complexity, reduces the bandwidth consumption and the memory requirements of the system, provides the quasi-orthogonal spreading codes and interleavers with a high security and offers infinite sets of codes and interleavers based on only one parameter. Second, we propose a new user grouping algorithm based on the correlation function to improve the resources (Codes, Interleavers). All users are divided into several equal-size groups where each group's data transmitted at the same time, over the same frequencies and the same interleaver. The simulation results indicate that the proposed scheme can achieve better performances compared to the existing algorithms.

Wideband SiN pulse interleaver for optically-enabled analog-to-digital conversion: a device-to-system analysis with cyclic equalization.

We present the design and experimental characterization of a silicon nitride pulse interleaver based on coupled resonator optical waveguide filters. In order to achieve a targeted free spectral range of 1.44 THz, which is large given the reduced optical confinement of the silicon nitride platform, individual ring resonators are designed with tapered waveguides. Its application to time-interleaved photonically-assisted ADCs is analyzed by combining experimental characterization of the photonic integrated circuit with a comprehensive model of the entire ADC. The impact of fundamental signal distortion and noise sources affecting the converter is investigated and suitable equalization techniques at the digital signal processing level are evaluated. The novel application of a simple but powerful equalization filter in the DSP domain allows for a significant improvement of the digitized signal SNR. An ENOB of 5 over a 75 GHz bandwidth (150 GS/s) and an ENOB of 4.3 over a 100 GHz bandwidth (200 GS/s) are expected to be achievable with compact and off-the-shelf single-section semiconductor mode locked lasers, that can be further improved with lower noise light sources.

Probabilistic Shaping for Protograph LDPC-Coded Modulation by Residual Source Redundancy

Probabilistic amplitude shaping (PAS) has proved to be a promising way to achieve the shaping gain for an additive white Gaussian noise channel with a distribution matcher (DM). However, the DM schemes may suffer a rate loss and increase both complexity and latency, when they are not suited for the input bit stream with redundancy. In this paper, a novel PAS strategy is proposed for a joint source and channel coded modulation system, where the residual source redundancy after source coding can be exploited to obtain both shaping and coding gains. It is shown that the residual source redundancy can be controlled by choosing the row weight distribution for source code, thus making the probability distribution of the modulated symbols be optimized under an appropriate interleaver design. To guarantee the error-floor performance, the source code is constrained by predicting the probability distribution of source bits within target finite-length frames. By jointly designing source and channel codes, the residual source redundancy can also be exploited to achieve the coding gain. Compared with the state-of-the-art code pairs, the proposed code pairs have better error-floor performance, and achieve higher coding and shaping gains without suffering from the rate-loss and the latency caused by DM.

Design of Interleaver with High Dimensional Encoding Principle using Hybrid Group Search Optimization

Design of Interleaver with High Dimensional Encoding Principle using Hybrid Group Search Optimization

Interleaver Design for Small-Coupling-Length Spatially Coupled Protograph LDPC-Coded BICM Systems Over Wireless Fading Channels

As a class of convolutional error-correction codes (ECCs), spatially coupled protograph low-density parity-check (SC-PLDPC) codes with a sufficiently large coupling length can approach the channel capacity under belief propagation (BP) decoding. However, such codes suffer from poor performance in the case of small coupling lengths. To address the above weakness, we investigate the optimization and analysis of SC-PLDPC-coded bit-interleaved coded modulation (BICM) systems over Rayleigh fading channels. Specially, inspired by the unequal-error-protection (UEP) mechanism of M-ary phase-shift keying/ quadrature amplitude modulation (M-PSK/QAM), we put forward a novel interleaver design scheme, referred to as spatial position match mapping (SPMM) scheme. Based on the mutual information (MI) analysis, the proposed interleaver can be used to significantly boost the performance of the SC-PLDPC codes in BICM systems. Furthermore, we propose a block-scheduling protograph-based extrinsic information transfer (BS-PEXIT) algorithm to estimate the convergence performance (i.e, decoding threshold) of the SPMM-aided SC-PLDPC codes in BICM scenarios. Simulation results are well consistent with the theoretical analyses, and show that the proposed SPMM-aided SC-PLDPC-coded BICM systems are superior to the state-of-the-art counterparts.

A new optimised interleaver design for high-dimensional data transmission in SCM-OFDM system

This paper intends to develop a new interleaver design for SCM-OFDM system. Initially, a set of data is transmitted though SCM-OFDM system, for different Signal-to-Noise Ratios (SNR). In the interleaver of SCM-OFDM, the scramble rule generation is considered as the challenging point, which needs to be optimised to make the system more effective by arranging data in a non-contiguous way. Accordingly, the optimal scramble generation is introduced in this paper using the hybridisation of Rider Optimisation Algorithm (ROA) and Group Search Optimisation (GSO) algorithms. The new hybrid algorithm is termed as GSO Bypass based ROA (GB-ROA). In the receiver side, the same optimised scramble rules are utilised in the deinterleaver, and mean error is computed between the transmitted and received data, considering the entire allotted data. The iterative process of scramble rule generation is repeated until the mean error is a minimum. Finally, the presented model is compared with conventional schemes.

A new optimised interleaver design for high-dimensional data transmission in SCM-OFDM system

This paper intends to develop a new interleaver design for SCM-OFDM system. Initially, a set of data is transmitted though SCM-OFDM system, for different Signal-to-Noise Ratios (SNR). In the interleaver of SCM-OFDM, the scramble rule generation is considered as the challenging point, which needs to be optimised to make the system more effective by arranging data in a non-contiguous way. Accordingly, the optimal scramble generation is introduced in this paper using the hybridisation of Rider Optimisation Algorithm (ROA) and Group Search Optimisation (GSO) algorithms. The new hybrid algorithm is termed as GSO Bypass based ROA (GB-ROA). In the receiver side, the same optimised scramble rules are utilised in the deinterleaver, and mean error is computed between the transmitted and received data, considering the entire allotted data. The iterative process of scramble rule generation is repeated until the mean error is a minimum. Finally, the presented model is compared with conventional schemes.

Performance analysis of the odd–even uniform interleaver for turbo codes

Interleaver design has been an intense research area since the invention of turbo codes, both from theoretical and technological perspectives, still receiving the attention of engineers. This work is a theoretical treatment on the subject of interleaver design, bringing into focus the odd-even constraint. Odd-even interleavers constrain information symbols at odd (even) positions to remain at odd (even) positions after interleaving. Having been adopted in a range of operational communication standards as parts of turbo codes on the one hand, and having raised scepticism about their gain in the literature of turbo trellis-coded modulation on the other hand, these interleavers have motivated the present article. Concretely, the authors perform a bit-error analysis of turbo-code ensembles generated by the odd–even uniform interleaver , following the union-bound approach by Benedetto et al. for the analysis of the uniform interleaver. They find that the odd–even constraint does not affect the interleaver gain of uniform-interleaver ensembles; rather, it triggers a redistribution of multiplicities that leads to slightly worse performance mainly in the error-floor region. The authors' findings are corroborated by bit-error-rate simulations.

Joint Interleaver and Modulation Design For Multi-User SWIPT-NOMA

Radio frequency (RF) signals can be relied upon for conventional wireless information transfer (WIT) and for challenging wireless power transfer (WPT), which triggers the significant research interest in the topic of simultaneous wireless information and power transfer (SWIPT). By further exploiting the advanced non-orthogonal-multiple-access (NOMA) technique, we are capable of improving the spectrum efficiency of the resource-limited SWIPT system. In our SWIPT system, a hybrid access point (H-AP) superimposes the modulated symbols destined to multiple WIT users by exploiting the power-domain NOMA, while WPT users are capable of harvesting the energy carried by the superposition symbols. In order to maximise the amount of energy transferred to the WPT users, we propose a joint design of the energy interleaver and the constellation rotation based modulator in the symbol-block level by constructively superimposing the symbols destined to the WIT users in the power domain. Furthermore, a transmit power allocation scheme is proposed to guarantee the symbol-error-ratio (SER) of all the WIT users. By considering the sensitivity of practical energy harvesters, the simulation results demonstrate that our scheme is capable of substantially increasing the WPT performance without any remarkable degradation of the WIT performance.

Simplified on-The-Fly IAG QPP Interleaver for Turbo Channel Coding Scheme

Interleaver is an indispensable component in the design of Turbo encoder and Turbo Decoder. QPP interleaver is a 3GPP specified conflict free interleaver for turbo channel coding scheme for all code block sizes of 40 to 6144. Thus the efficient design of a conflict free reconfigurable QPP interleaver for turbo encoder and turbo decoder is a pre-eminent task in turbo channel coding scheme. In this article, Design of a simplified reconfigurable (40 to 6144 block sizes) Recursive QPP interleaver for computation of address locations to minimize the computational complexity and to avoid storage of interleaver tables has been presented. The proposed interleaver will be further integrated in the design and implementation of high throughput parallel turbo decoder. The proposed design is synthesized and implemented using 28nm CMOS technology Zynq Zed FPGA and achieved low processing timing constraints, utilization and power constraints compared with other conventional designs.

On the Performance of Interleavers for Quantum Turbo Codes.

Quantum turbo codes (QTC) have shown excellent error correction capabilities in the setting of quantum communication, achieving a performance less than 1 dB away from their corresponding hashing bounds. Existing QTCs have been constructed using uniform random interleavers. However, interleaver design plays an important role in the optimization of classical turbo codes. Consequently, inspired by the widely used classical-to-quantum isomorphism, this paper studies the integration of classical interleaving design methods into the paradigm of quantum turbo coding. Simulations results demonstrate that error floors in QTCs can be lowered significantly, while decreasing memory consumption, by proper interleaving design without increasing the overall decoding complexity of the system.

Interleaver Design for Short Concatenated Codes

The choice of the interleaver may significantly affect the performance of short codes when they are used in serial concatenation. By focusing on the minimum distance of the overall concatenated code, we propose an algorithmic method for the design of good interleavers. As a valuable example of application, we consider the case of polar codes concatenated with cyclic redundancy check codes. For these codes, the method we propose is compared with classical approaches based on random searches to assess its advantages, which are also confirmed through examples of practical coded transmissions over the binary erasure channel.

Analysis and design of tent map interleaver for interleave division multiple access scheme

Interleavers are the main component of almost all multiple access systems, such as Code Division Multiple Access (CDMA) and Interleave Division Multiple Access (IDMA henceforth). In IDMA systems, interleavers are crucially important for user separation that consequently also contributes maximising the system throughput. The paper intends to claim an efficient Tent map based design of interleaver (TMI henceforth) generation which has less computational complexity and is more efficient in bandwidth compared to the existing prevailing algorithms in the domain. The proposed scheme is based on chaos theory and the simulation results show that TMI based IDMA can achieve the good BER performance without the need of extra memory resources.

Analysis and design of tent map interleaver for interleave division multiple access scheme

Analysis and design of tent map interleaver for interleave division multiple access scheme

A Fast Computational Interleaver Design for Iterative IDMA Scheme Based on Tent Map and Chaos

A Fast Computational Interleaver Design for Iterative IDMA Scheme Based on Tent Map and Chaos

Performance analysis of modified tent map interleaver in IDMA systems

Abstract In the last years, Interleave Division Multiple Access (IDMA) has been presented as a potential alternate of Code Division Multiple Access (CDMA) system. In IDMA systems, the interleavers are used to separate the users of the system in multiple access environments. Random interleaver is popular and basic taxonomy, which scrambles information bits of craving users with different patterns. However the indispensable characteristics of a random interleaver such as bandwidth requirement, computational complexity, and memory restraint at both transmitter and receiver end is uttermost. Further, it has also been observed that the study of role of chaos in interleaver design is very limited in literature. Hence, in this paper, a low complexity chaos based interleaver named as modified Tent map interleaver is designed for further performance improvement of IDMA system and the characteristic parameters are compared with the random interleaver. The IDMA system model uses a BPSK modulation and repetition coder with a code rate of 1/2. The system is simulated in MATLAB and results show that the better BER performance without the need of extra memory resources.

Design and Experimental Demonstration of a Compact Silicon Photonic Interleaver Based on an Interfering Loop With Wide Spectral Range

We present the design and experimental demonstration of a compact tunable silicon photonic interleaver with a wide spectral range. The interleaver consists of an interfering loop containing a Fabry–Perot cavity formed by two Sagnac loops. The transmission coefficients of the directional couplers are calculated based on the maximally flat criterion. The impacts of the transmission coefficient variations on the extinction ratio and filter sharpness are investigated. The wavelength dependences of the directional couplers are analyzed to increase the spectral range of the interleaver. The device was fabricated on a silicon-on-insulator platform. The spectral ranges of the measured transmission and reflection spectra are increased to 60 nm. By thermal tuning the waveguide connecting the two Sagnac loops, the central wavelength can be shifted over one free spectral range with a wavelength-tuning efficiency of ∼0.08 nm/mW.

Turbo Coded OFDM Combined with MIMO Antennas Based on Matched Interleaver for Coded-Cooperative Wireless Communication

A turbo coded cooperative orthogonal frequency division multiplexing (OFDM) with multiple-input multiple-output (MIMO) antennas scheme is considered, and its performance over a fast Rayleigh fading channel is evaluated. The turbo coded OFDM incorporates MIMO (2 × 2) Alamouti space-time block code. The interleaver design, and its placement always plays a vital role in the performance of a turbo coded cooperation scheme. Therefore, a code-matched interleaver (CMI) is selected as an optimum choice of interleaver and is placed at the relay node. The performance of the CMI is evaluated in a turbo coded OFDM system over an additive white Gaussian noise (AWGN) channel. Moreover, the performance of the CMI is also evaluated in the turbo coded OFDM system with MIMO antennas over a fast Rayleigh fading channel. The modulation schemes chosen are Binary Phase shift keying (BPSK), Quadrature phase shift keying (QPSK) and 16-Quadrature amplitude modulation (16QAM). Soft-demodulators are employed along with joint iterative soft-input soft-output (SISO) turbo decoder at the destination node. Monte Carlo simulated results reveal that the turbo coded cooperative OFDM system with MIMO antennas scheme incorporates coding gain, diversity gain and cooperation gain successfully over the direct transmission scheme under identical conditions.