Trellis Codes Research Articles

Data Hiding in Iris Image for Privacy Protection

ABSTRACTThis paper proposes a novel iris image data hiding scheme for privacy protection. Privacy personal data is embedded into the iris image such that its impact on the iris recognition is minimised. This is achieved by restricting the modifications of the embedding within the regions that seldom affects the iris recognition with the help of the STC (syndrome trellis coding) framework. We also propose a novel distortion function to measure the impact of the data embedding on iris recognition, where the regions with important iris features are assigned with high embedding cost. Experimental results show that, by using our proposed scheme, we can embed sufficient data into the iris image with high recognition accuracy maintained.

Concatenated LDPC-TCM Codes for Better Performance of OFDM-FSO System Using Gamma–Gamma Fading Model

Various channel coding techniques have been used for free space optical (FSO) links to alleviate the effects of fading, induced due to turbulence. In this paper, the error rate performance is scrutinized for orthogonal frequency division multiplexing based FSO system with 16-QAM modulation, and the effect of several atmospheric turbulence conditions has been analyzed. Due to atmospheric turbulence, the arbitrary fluctuations of optical irradiance are modelled by widely used Gamma-gamma distribution model. The various channel coding schemes has been analyzed and a new hybrid coding scheme (the outer low-density parity check codes efficiently integrated with interleaved trellis code modulation codes) is developed, which has shown superior performance under all turbulence conditions and outperform the other individual coding schemes. The proposed hybrid scheme is analyzed for single antenna fading channels to achieve better error rate performance.

Code Design for Discrete Memoryless Interference Channels

We study the design of explicit and implementable codes for the two-user discrete memoryless interference channels (DMICs). We consider Han–Kobayashi (HK) type encoding where both public and private messages are used and propose coding techniques utilizing a serial concatenation of a nonlinear trellis code (NLTC) with an outer low-density parity-check (LDPC) code. Since exact analytical treatment of the BCJR decoder for the inner trellis-based code appears infeasible, we analytically investigate the iterative decoding process in the asymptotic regime where the probability of decoding error tends to zero. Based on this approximate analysis, we derive a stability condition for this type of a concatenated coding scheme for the first time in the literature. Furthermore, we use an extrinsic information transfer analysis to design the outer LDPC code while fixing the inner NLTC, and utilize the derived stability condition to accelerate the design process and to avoid code ensembles that potentially produce high error floors. Via numerical examples, we demonstrate that our designed codes achieve rate pairs close the optimal boundary of the HK subregion, which cannot be obtained without the use of nonlinear codes. Also, we verify that the estimated thresholds of the designed codes via finite block length simulations and show that our designs significantly outperform the point-to-point optimal codes, hence demonstrating the need for designs specifically tailored for DMICs.

STTC design for vehicular communication systems employing fixed‐gain AF PLNC over cascaded fading channels

In this study, the authors combine physical layer network coding (PLNC) and space-time trellis coding (STTC) techniques to improve the error performance of vehicle-to-vehicle (V2V) communication systems where all fading channels are assumed to undergo double Rayleigh fading (DRF) which is worse than Rayleigh fading used in cellular communications. In the authors' analysis, they show that the DRF channels can be modelled by using the mixture gamma distribution. After that, pairwise error probability (PEP) analysis is performed for a fixed-gain amplify-and-forward PLNC V2V system employing STTC over the DRF channels, and an upper bound for the PEP is obtained. By examining the behaviour of the upper bound expression in the high SNR region, they derive a new design criterion for STTCs. Finally, using this criterion they propose novel STTCs with 4 and 8 states for V2V systems employing PLNC over the DRF channels.

Trellis coded quadrature spatial modulation

In this paper, a novel multiple-input multiple-output (MIMO) transmission scheme called trellis coded quadrature spatial modulation (TC-QSM), is proposed. In the proposed scheme, trellis coded modulation (TCM) principle is applied to the emerging quadrature spatial modulation (QSM) scheme, and a trellis encoder and a QSM mapper are jointly designed to benefit from both coding and multiplexing gains. At the receiver side, a soft-decision Viterbi decoder is used along with a QSM decoder to obtain the optimum error performance. Considering our design criterion, TC-QSM schemes are designed for different number of trellis states, transmit antennas and spectral efficiencies. The pairwise error probability (PEP) of the TC-QSM scheme is derived over quasi-static Nakagami-m, Rician and Rayleigh fading channels and an upper bound on the average bit error probability (BEP) is obtained. Through comprehensive Monte Carlo simulations, the effect of signal and spatial bits on uncoded and trellis coded SM and QSM schemes over Nakagami-m and Rician fading channels are investigated for different fading parameters. Moreover, the error performance of the TC-QSM and SM with trellis coding (SM-TC) schemes are compared for different spectral efficiency values, where it is revealed that the proposed TC-QSM scheme provides an interesting trade-off between performance and implementation cost, and achieves an improved error performance over reference schemes including SM, QSM and SM-TC.

Improving the Performance of Trellis Coded Modulation Over Rayleigh Fading Channel Using Locally Rotated Constellations

In this paper, we propose a new type of modulation technique; it is called Locally-Rotated (LR) modulation. With this new technique we are looking to optimize the channel encoding block named “Trellis-Coded Modulation with a Locally-Rotated constellation” (TCM+LR). This channel encoding block uses PSK/QAM mapping technique which takes into consideration both Ungerboeck mapping and Gray code mapping (UGM). The simulation results, over Rayleigh fading channels and Proakis B, are performed for throughput 2 and 3 bits/s/Hz with 8PSK and 16 QAM modulations, and rate 2/3, 3/4 constituent TCM encoders with memory order of 3, 4 and 5. In the Rayleigh fading channel, the results show that the proposed scheme TCM+LR-UGM with three memories produces a slight improvement in comparison to TCM+LR, by increasing the number of memories to four. It is shown that TCM+LR-UGM outperforms the TCM+LR Ungerboeck mapping by a gain of 2.5 dB and we notice a gain of 5 dB compared to the 8 state TCM+LR, moreover, a gain of 7.5 dB is achieved in comparison with the original TCM with three memories. In the selective frequency channel, the results show that the proposed scheme TCM+LR-UGM with four memories outperforms the TCM+LR Ungerboeck mapping with a gain of 1 dB and outperforms the TCM+LR with three memories with a gain of 2 dB and with a gain of 3 dB compared to the original TCM 8-states.

Turbo Trellis-Coded Differential Chaotic Modulation

In this brief, a novel turbo trellis-coded differential chaotic modulation (TTC-DCM) system is proposed, where parallel concatenated trellis codes are combined with the M-ary differential chaotic shift keying (M-ary DCSK) scheme. An extrinsic information transfer chart is employed to analyze the convergence over additive white Gaussian noise channel and multipath Rayleigh channels. Simulation results show that the new scheme can obtain considerable coding gains without impairing the bandwidth efficiency in comparison with the M-ary DCSK scheme and the trellis-coded differential chaotic modulation scheme. Moreover, compared to the direct-sequence spread-spectrum turbo trellis-coded modulation scheme, TTCDCM has lower complexity and better robustness in the absence of channel state information over multipath Rayleigh channels. Overall, because of the merits of promising performance, high bandwidth efficiency, robustness to poor channel conditions, and an easy-to-implement property, the TTC-DCM scheme is suitable for bandlimited communication applications under poor channel conditions.

FDMA System with Space\u2013Time Encoded CPM Signals

The paper considers a multiple-antenna uplink wireless transmission (MIMO) system in a Frequency Division Multiple Access multi-user environment. It involves a concatenation of Space–Time Block or Trellis Codes (STBC or STTC) with Continuous Phase Modulation (CPM). For a more efficient available band utilization, the distances between individual system user carriers are small (tight intercarrier frequency spacing). Such a solution causes the deterioration of transmission quality due to the occurrence of Inter-Channel Interference (ICI). In order to reduce the bit error rate (BER), a combination of CPM and STTC has been used, along with a Minimum Mean Square Error (MMSE) MIMO detector and a low-complexity iterative algorithm for Inter-Carrier Interference (ICI) cancellation on the receiver side. BER results obtained in computer simulations are presented for the proposed system.

Lossy Source Coding for Non-Uniform Binary Source with Trellis Codes

Lossy Source Coding for Non-Uniform Binary Source with Trellis Codes

An Adaptive JPEG Steganographic Scheme Based on Run‐Length Statistical Complexity

This paper presents a novel adaptive JPEG steganographic scheme in Discrete cosine transform (DCT) domain using Run-length statistical complexity (RSC). Unlike the traditional complexity measurements, RSC considers the change randomness of DCT coefficients in image blocks. The distortion functions in both side-informed and non-side-informed schemes are derived by RSC and minimized by Syndrome trellis coding (STC). Experimental results show superior performance of our scheme over a wide range of embedding rates at different image quality factors compared with previous three common steganographic schemes.

Optimized SCMA Codebook Design by QAM Constellation Segmentation With Maximized MED

An optimized design of a sparse code multiple access (SCMA) codebook for uplink wireless communications is presented by dividing an optimized 16-point round quadrature amplitude modulation (QAM) into several subsets. The main goal of the scheme is to maximize the minimum Euclidean distance and thus reduces the collisions of the information bits on the resources. The final SCMA codebook is obtained with the mapping matrix, which indicates the sub-constellations generating by dividing the mother QAM constellation. Simulation results show that, in a Nakagami fading channel, the optimized SCMA scheme by the proposed design method achieves significantly performance gains approximately 1.0, 1.4, 2.5, 3.5, and 4.0 dB at bit error rate of $10^{-4}$ , respectively, when compared with those of an undivided 16-QAM constellation, a trellis code modulation (TCM) division, an original SCMA codebooks, a low-density signature (LDS), and an irregular LDS (IrLDS) schemes. In addition, at the signal-to-noise ratio ranging from 0 to 10 dB, the constellation constrained capacity of the scheme by the proposed method achieves more gains over those of the original SCMA, TCM, the undivided star-QAM, the LDS, and the IrLDS schemes. Thus, it can be combined with the grant-free random access mechanism to obtain rapid and low-cost access in next-generation wireless packet services and other applications.

Trellis Code Design of Block Interleaved CIOD-STBCs for Time Varying Channels

A trellis-code design scheme is proposed for a coordinate interleaved orthogonal design space-time block code (CIOD-STBC) system employing a time interleaver. The pairwise error probability (PEP) for the block interleaved CIOD-STBC is analytically derived, and the PEPs are evaluated to search the best systematic feedback encoder to provide the maximum diversity and coding gain for several numbers of states. We expand the signal set such that the expanded set has the same transmit symbol set to keep both the bandwidth and the peak-to-average power ratio the same as the uncoded system. It is noteworthy that the proposed system provides approximately 9-dB SNR gain over the uncoded system at bit error rate ${10^{-5}}$ in the quasi-static Rayleigh fading channel with 32 state trellis coded CIOD. Simulation results are also provided to verify the theoretical analysis.

위성통신을 위한 터보 등화기를 사용하는 8PSK-TCM 시스템 설계와 성능 평가

In this paper, as a basic study for combination of turbo equalizer and 4D-8PSK-TCM(4 Dimensional 8 Phase Shift Keying Trellis Coded Modulation) system, which is recommended for X-band band satellite communication in CCSDS, a system combining 8PSK-TCM system and turbo equalizer has designed and performance evaluation of the system has performed. BER performance of 8PSK and 8PSK-TCM systems has evaluated and analyzed in AWGN, Proakis B and Proakis C channels in detail. As results of simulation, BER performance of 8PSK-TCM system is better than 8PSK system in AWGN environment. Furthermore, it can be confirmed that the system combining the 8PSK-TCM system with the turbo equalizer can further improve the BER performance through iterative equalization in the ISI channel environment. The 8PSK-TCM system combined with the turbo equalizer requires SNR of 5.9 dB for BER performance of 10−3 with 5 iterative equalization in Proakis B and SNR of 9.1 dB for BER of 10−2 with 5 iterative equalization in Proakis C.

A new algorithm and routing protocol based on convolutional codes using TCNet: Trellis Coded Network

Currently emerging technologies have taken advantage of the possibility of communication with the World Wide Web to expand to all applications of this technology, among them the Internet of Things – IoT. This work proposes the implementation of new packets forwarding algorithms using the concept of convolutional codes. The results obtained by means of extensive simulations show gains in terms of latency and energy consumption reduction compared to the AODV protocol. The implementation complexity is extremely low and compatible with the few hardware resources usually available in the elements of a wireless sensor network (WSN). This research uses Finite State Machine (FSM) to get the networks nodes, obtained from settings with Mealy machine – (MM) due to the low complexity of (“XOR” gates and "shift registers"), eliminating the use of any routing tables by means of Trellis decoding. The route can be chosen based on criteria of Quality of Service (Qos) – aware routing protocols.

Redesigned Spatial Modulation for Spatially Correlated Fading Channels

In this paper, a new variant of Spatial Modulation (SM) Multiple-Input Multiple-Output (MIMO) transmission technique, designated as Redesigned Spatial Modulation (ReSM) has been proposed. In ReSM scheme, a dynamic mapping for antenna selection is adopted. This scheme employs both single antenna as well as double antenna combinations depending upon channel conditions to combat the effect of spatial correlation. When evaluated over spatially correlated channel conditions, for a fixed spectral efficiency and number of transmit antennas, ReSM exhibits performance improvement of at least 3 dB over all the conventional SM schemes including Trellis Coded Spatial Modulation (TCSM) scheme. Furthermore, a closed form expression for the upper bound on Pairwise Error Probability (PEP) for ReSM has been derived. This has been used to calculate the upper bound for the Average Bit Error Probability (ABEP) for spatially correlated channels. The results of Monte Carlo simulations are in good agreement with the predictions made by analytical results. The relative gains of all the comparison plots in the paper are specified at an ABER of 10−4.

Spectral Efficiency Improved 2D-PAM8 Trellis Coded Modulation for Short Reach Optical System

This paper proposes and demonstrates a 31.25 Gbps two-dimensional eight level pulse amplitude modulation with trellis coded modulation (2D-PAM8-TCM) transmission in intensity modulation and direct detection based short reach system. In this system, the commercial directly modulated laser and photodiode with trans-impedance amplifier (PIN-TIA) with a combined modulation bandwidth of ∼16 GHz are used as transmitter and receiver, respectively. For 2D-PAM8-TCM signals, except for regular 8-state convolutional encoder, both 16-state and 32-state encoders are provided. Considering the coding gain and the complexity of convolutional encoder, the 16-state one is recommended. Moreover, instead of Viterbi decoder, the M-algorithm is utilized at the receiver side to reduce decoder complexity. It is experimentally demonstrated that 2D-PAM8-TCM scheme can achieve 2.5 b per symbol and ∼0.5 dB sensitivity improvement (bit error rate @ $3.8 \times {10^{ - 3}}$ ) over a 20 km standard single mode fiber in comparison with conventional PAM4. Thanks to no additional digital signal processing in receiver side except M-algorithm, this scheme is simple and effective, which can be considered as an attractive technique for future short reach system.

Distortion function based on residual blocks for JPEG steganography

Steganography aims to embed additional data into digital media secretly and minimize the distortion caused by data embedding. Up to now, the key point of minimal distortion embedding framework is to design proper distortion function. In this paper, a distortion function for JPEG steganography based on residual blocks is proposed. To obtain less statistical detectability, Residual Block Values (termed as RBVs for short) and quantization steps are both involved in the proposed distortion function. RBVs are exploited to determine the embedding risk caused by modifications in corresponding DCT block while quantization steps are exploited to determine the embedding risk of the selection channel in a block. By implementing the syndrome trellis coding (STC) to embed secret data, the modifications are constrained in hard-to-detect religions. Experiments show that the proposed method performs better than current state-of-the-art methods of JPEG steganography.

A Survey of Coding and Modulation Techniques for Inter-Vehicular Communications

Direct inter-vehicular communication means that there is no infrastructure. This is in sharp contrast to mobile communication within a cellular network or between a moving vehicle and the roadside. It is assumed in this article that the mobile channel between the two vehicles is too rapidly time variable to be possible to measure it in real-time. The natural choice is then to select those coding and modulation techniques for which the knowledge of the channel state is not necessary at both the transmitter and the receiver, that is, to consider only differential and noncoherent communications technologies. As interesting options, the celebrated Golden code and the recently developed Golden-Alamouti space-time trellis coding are also proposed for inter-vehicular communications.

Space–Time Trellis-Coded OFDM Systems in Frequency-Selective Mobile Fading Channels

Space–time trellis code (STTC) techniques provide both coding gain and diversity gain to orthogonal frequency-division multiplexing (OFDM) systems without reducing bandwidth efficiency. However, factors such as residual carrier frequency offset due to Doppler shift destroy the orthogonality among subcarriers, which results in intercarrier interference (ICI) in mobile fading channels and bit error rate (BER) degradation. This brief presents three STTC-based OFDM systems to improve BER in frequency-selective mobile fading channels. First, a new STTC-ST method is developed with OFDM to form a new STTC-ST-OFDM system. Second, a Walsh–Hadamard (WH) transform is employed as a precoder to form a new STTC-WH-ST-OFDM system with limited growing computation. Third, the STTC-WH-ST-OFDM system is integrated with an ST conjugate cancelation (CC) scheme to form an STTC-WH-STCC-OFDM transceiver with expanding bandwidth in order to combat ICI. Simulations indicate that the STTC-WH-STCC-OFDM system outperforms both STTC-WH-ST-OFDM and STTC-ST-OFDM systems, whereas the STTC-WH-ST-OFDM system outperforms the STTC-ST-OFDM system. All three schemes are simple and are backward compatible with existing OFDM systems. They can serve as baseband building blocks for multiuser OFDM systems, specifically in downlink networks.

Improvement of MIMO System using STTC with Artificial Neural Network

The wide demand for high data rate rapid development in mobile and internet communication system limitation of the radio spectrum and the communication capacity needs cannot be met without a significant increase in communication spectral efficiency make it important to increase the capacity and decrease the Bit Error Rate (BER) of communication channel. In this paper, analysis of the capacity for four types of communication systems are performed, it was found that the MIMO communication system capacity is the best, Space Time Trellis Code (STTC) technique is used to improve the performance of MIMO system by decreasing the BER as well as possible, finally artificial neural network was used at the receiver of with (STTC) to get more suitable results by decreasing the BER of the proposed system.