Space-time Trellis Codes Research Articles

Non-orthogonal Amplify and Forward Relay Selection Systems with Distributed Space–Time Trellis Coded Continuous Phase Modulation

Most of the works on cooperative systems with or without relay selection have focused on linear modulations such as phase shift keying and quadrature amplitude modulation. Whereas, continuous phase modulation (CPM) is a good alternative to these modulations due to its constant envelope property which enables us to use inexpensive and energy-efficient non-linear power amplifiers. In the literature, a few works are based on relaying systems with CPM. To the best of our knowledge, none exists with relay selection. In this paper, we propose single and multiple relay selection CPM schemes based on a new generalized relay selection criterion for non-orthogonal amplify and forward (AF) systems operating with various time sharing protocols. In particular, using the proposed criterion, the best relay or the best two relays over a set of four available relays is/are selected. Error performances of the non-orthogonal AF relay selection systems and their counterparts are compared over frequency non-selective quasi-static Rayleigh fading channels using Viterbi algorithm at the destination terminal. Our numerical results present superiority of the proposed non-orthogonal relay selection systems.

Performance Analysis of Adaptively Grouped Multilevel Space-Time Trellis Coded Systems using Different Component Codes

Adaptively grouped multilevel space-time trellis codes (AGMLSTTCs) utilize multilevel coding (MLC), space time trellis codes (STTCs) and adaptive transmit antenna grouping for simultaneously providing coding gain, diversity improvement and increased spectral efficiency. AGMLSTTCs use Chen, Yuan, and Vucetic (CYV) STTCs as component codes in MLC. In this paper, we present performance comparison of AGMLSTTCs generated using different component STTCs. We use Tarokh, Seshadri, and Calderbank (TSC), Baro, Bauch and Hansmann (BBH) and CYV codes as component STTCs. The simulation results show that AGMLSTTCs with CYV as component STTCs outperforms in comparison with the AGMLSTTCs with TSC and BBH as component STTCs.

Performance evolution of trellis coding in Multiple Input Multiple Output communication systems—A review

In recent years, it has been realized that the Multiple Input Multiple Output (MIMO) communication system is inevitable in accelerating the evolution of high data rate applications. Also the latest research in Information and Communication Technology has told that considerable gains in capacity of wireless communication are feasible in MIMO systems. MIMO with Space Time Trellis Code (STTC) offers both diversity gain and coding gain. This paper discusses the evolutional variants of Space Time Trellis Code developed over a decade. The performance of New Trellis code for STTC, STTC for 4-PSK, Space Frequency Trellis code (SFTC), Space Time Bit Trellis Code, and Silver STTC have been studied and discussed. STTC with Trellis Coded Modulation creates a bandwidth efficient system with coding gain.

Application of space–time Trellis codes for multicarrier delay diversity modulation systems

This study investigates the performance of multicarrier delay diversity modulation (MDDM) systems with both cyclic delay diversity and space–time Trellis code (STTC) techniques and compares its performance with conventional MDDM systems. Deploying STTCs can allow cost efficient and flexible system deployment compared with classical MDDM systems with multiple cyclic delays. In this study, the authors’ propose MDDM systems with both cyclic delay and STTCs. The MDDM system is modelled for two and four transmit antennas. In this study, they compare the performance of the proposed MDDM systems with quadrature phase shift keying (QPSK), 8 phase shift keying (8PSK) and 16 quadrature amplitude modulation (16QAM) STTCs and compare its results with conventional MDDM systems. The noise variance of the received signals at the MDDM receiver is mathematically derived. The minimum mean square error technique for channel estimation is applied to the proposed MDDM systems. Simulation results demonstrate that the proposed MDDM systems enhance the performance of classical MDDM systems and give large coding gains compared with the classical case.

Study on the Channel Model and BER Performance of Single-Polarization Satellite-Earth MIMO Communication Systems at Ka Band

The statistic models for evaluating the fading term caused by the incoherent scatter in clear and rainy environments are derived, which are critical for establishing the multiple-input multiple-output (MIMO) channel model at Ka band. The channel model of Ka-band single-polarization MIMO satellite-earth link is established, which comprehensively takes into account the propagation and scattering effects induced by those environments. Based on the channel model, the bit error rate (BER) performances in clear and rainy environments are investigated taking an assumed 2 × 2 satellite-earth link at 30 GHz in circular polarization as an example. During the investigation, the M-ary Phase Shift Keying (M-PSK) modulation modes with different M and the space-time codes of Space-Time Block Code (STBC), Space-Time Trellis Code (STTC) and Vertical Bell Laboratories Layered Space-Time (VBLAST) are considered. It is also discussed that the BER varies with propagation environment parameters, equivalent isotropically radiated power (EIRP), ground receiving antenna gain and elevation angle. The channel model given in this paper is also valid for the single-polarization MIMO satellite-earth link at other frequencies above 10 GHz.

수중통신에서 Zero Forcing기법을 이용한 최적의 시공간 부호화 알고리즘

수중통신에서는 다중경로로 인해 심벌간의 상호간섭이 발생하여 시스템의 성능을 저하시킨다. 최근 수중 통신시스템에서는 이러한 열악한 채널환경을 극복하고 전송률을 향상시키기 위하여 등화기 및 채널 부호화와 시공간 부호화 방식의 효율적인 연접 구조가 수중통신에서 MIMO시스템으로 응용되어 연구되고 있다. 수중 MIMO 환경에서 시공간 부호화 방식 중에서는 시공간 블록 부호화 방식과 시공간 격자 부호화 방식이 있으며, 시공간 격자 부호화 방식이 등화기 및 채널 부호화 방식에 최적이다. 따라서 본 논문에서는 다중경로 채널 환경에서 효율적인 전송을 위해 터보 Pi 부호화기를 외부부호로 사용하고, MIMO시스템에서 전송 다이버시티와 부호화이득을 동시에 가지는 시공간 격자부호를 내부부호로 구성한다. 그리고 심볼간 상호 간섭 제거를 위해 Zero Forcing 등화기법을 사용하여 수중채널에서의 시뮬레이션을 통해 성능을 확인하였다. In the underwater communication, the performance of system is reduced because of the inter-symbol interference occur by the multi-path. In the recent years, to deal with poor channel environment and improve the throughput, the efficient concatenated structure of equalization, channel codes and Space Time Codes has been studied as MIMO system in the underwater communication. Space Time Codes include Space Time Block Codes and Space Time Trellis Codes in underwater communication. Space Time Trellis Codes are optimum for equalization and channel codes among the Space Time Codes to apply in the MIMO environment. Therefore, in this paper, turbo pi codes are used for the outer code to efficiently transmit in the multi-path channel environment. The inner codes consist of Space Time Trellis Codes with transmission diversity and coding gain in the MIMO system. And Zero Forcing method is used to remove inter-symbol interference. Finally, the performance of this model is simulated in the underwater channel.

Weighted adaptively grouped multilevel space time trellis codes

In existing grouped multilevel space-time trellis codes (GMLSTTCs), the groups of transmit antennas are predefined, and the transmit power is equally distributed across all transmit antennas. When the channel parameters are perfectly known at the transmitter, adaptive antenna grouping and beamforming scheme can achieve the better performance by optimum grouping of transmit antennas and properly weighting transmitted signals based on the available channel information. In this paper, we present a new code designed by combining GMLSTTCs, adaptive antenna grouping and beamforming using the channel state information at transmitter (CSIT), henceforth referred to as weighted adaptively grouped multilevel space time trellis codes (WAGMLSTTCs). The CSIT is used to adaptively group the transmitting antennas and provide a beamforming scheme by allocating the different powers to the transmit antennas. Simulation results show that WAGMLSTTCs provide improvement in error performance of 2.6 dB over GMLSTTCs.

Hybrid Concatenated Super-orthogonal Space-time Frequency Trellis Coded MIMO-OFDM Systems

In this study, we propose two hybrids concatenated Super-Orthogonal Space-Time Trellis Codes (SOSTTC) applying iterative decoding in Orthogonal Frequency Division Multiplexing (OFDM) over frequency selective fading channels. The coding scheme is based on the concatenation of convolution coding, interleaving and space-time coding along multiple-transmitter/multiple-receiver diversity systems. The Pair wise Error Probability (PEP) for the two proposed concatenated schemes is derived and their performance is evaluated using computer simulation with Maximum a Posteriori (MAP) iterative decoding algorithm. Simulation results based on the iterative decoding process show a significant improvement in the achieved error rate performance of the concatenated scheme over existing concatenated designs.

Extensive Survey on MIMO Technology using V-BLAST Detection Technique

Wireless communication using Multiple Input Multiple Output (MIMO) systems increases efficiency for a given total transmits power. Here investigate a novel approach to perform decodingorder optimization in the vertical Bell Labs layered space-time (V-BLAST) planning. Allowing for instantaneous transmission of multiple, independently encoded data streams, the V-BLAST transmit-receive method applies to the uplink of a multi-user communication system. A multi-antenna receiver decodes data streams consecutively, trade with inter-stream interference by means of cancelling and nulling; interference from before decoded streams is cancelled by subtraction, and residual interference is nulled by linear equalization. The order in which the streams are decoded can have a visible impact on system presentation. Multiple Input Multiple Output (MIMO) channels can offer high capability to wireless systems and the capacity increases linearly with the number of antennas. There are many schemes that can be applied to MIMO systems such as space time block codes, space time trellis codes, and the Vertical Bell Labs Space-Time structural design (V-BLAST). We study the broad-spectrum MIMO system, the general VBLAST structure, and the Successive Interference Cancellation (SIC) Zero-Forcing (ZF) detectors in this paper.

Random Parameter EM-Based Kalman Filter (REKF) for Joint Symbol Detection and Channel Estimation in Fast Fading STTC MIMO Systems

In this work, we present a novel random parameter-based expectation-maximization (EM) algorithm for joint symbol detection and channel estimation in fast fading space-time trellis coded (STTC) multiple-input multiple-output (MIMO) wireless communication systems. Employing the EM framework with the MIMO channel as the random parameter, we demonstrate that this paradigm reduces to the optimal Kalman filter (KF)-based channel update in the E-step followed by a modified path metric-based maximum likelihood sequence decoder (MLSD) in the M-step. Further, we also present the pairwise error probability (PEP) upper bound for the frame error rate (FER) and the Bayesian Cramer-Rao bound (BCRB) for the proposed joint estimation scheme. Simulation results are presented to demonstrate the performance of the proposed technique and validate the analytical bounds.

Adaptively Grouped Multilevel Space–Time Trellis Codes Combined with Beamforming and Component Code Selection

The performance of adaptively grouped multilevel space---time trellis codes (AGMLSTTCs) is limited due to predefined component space---time trellis codes (STTCs) used in multilevel coding and lack of beamforming. In this paper, we present improvement in performance of AGMLSTTCs by combining beamforming and dynamic selection of component STTCs with AGMLSTTCs to design new codes henceforth referred to as weighted adaptively grouped multilevel dynamic space---time trellis codes. The channel state information at transmitter (CSI) is used to select a code set having different sets of generator sequences. The selected code set is used for generating dynamic STTCs (DSTTCs). The DSTTCs are used as component codes in multilevel coding. We use a single full-diversity DSTTC at some initial levels and multiple DSTTCs at some later levels. The single full diversity DSTTC at each initial level spans all transmit antennas and the DSTTC at each later level spans a group of transmit antennas. The CSI is further used to provide a beam forming scheme by properly weighting transmitted signals. Weights are selected that based on CSI at transmitter. The simulation results show that AGMLSTTCs combined with beamforming and DSTTCs provide significant improved error performance over grouped multilevel space---time trellis codes and AGMLSTTCs.

A novel grouped multilevel dynamic space–time trellis coding scheme

SummaryGrouped multilevel space–time trellis codes (GMLSTTCs) utilize multilevel coding, antenna grouping and STTCs for simultaneously providing coding gain, diversity improvement and increased spectral efficiency. The performance of GMLSTTCs is limited because of using predefined STTCs as component codes in multilevel coding. GMLSTTCs assume perfect channel state information (CSI) at the receiver only and do not consider the CSI at the transmitter. It has been shown that when perfect or partial CSI is available at the transmitter, the performance and capacity of a space–time coded system can be further improved. In this paper, we present new codes, designed by combining GMLSTTCs and the CSI information at the transmitter, henceforth referred to as grouped multilevel dynamic space–time trellis codes (GMLDSTTCs). A code set having different sets of generator sequences is selected that matches best with the current channel profile. The selected code set is used for generating DSTTCs. DSTTCs are used as component codes in GMLSTTCs instead of predefined STTCs to generate GMLDSTTCs. Analysis and simulation results show that GMLDSTTCs outperform GMLSTTCs. Copyright © 2014 John Wiley & Sons, Ltd.

Network Coded MIMO Aided Cooperative Communications in the Ambulance-and-emergency Area

In this contribution, a novel network coding (NC) aided multi-input multi-output (MIMO) scheme is proposed for providing reliable transmission from an ambulance assisting in an emergency situation by cooperating with relaying devices at an emergency scene. Our system is constituted by an Irregular Convolutional Coded Unity Rate Coded Space Time Trellis Coded M-ary Phase Shift Keying (IrCC-URC-STTC-MPSK) scheme invoked for exploiting the benefits of MIMO systems. The system is designed with the aid of Extrinsic Information Transfer (EXIT) charts for approaching the corresponding channel capacity in fast fading environments. The proposed scheme exhibits substantial benefits over conventional MIMO systems in hostile wireless channels.

BER Enhancement of MC-CDMA through B-STTC Based STBC and STBC Based B-STTC Site Diversity Techniques

The combination of multiple antennas and multi-carrier code division multiple access (MC-CDMA) is a strong candidate for the downlink of future mobile communications. The advancement of such systems, in scenarios that model real life transmissions is an additional step towards an optimised achievement. Nevertheless, when transmitting over fading channel multi-cell interference occurs and this degrades the performance of the system. Site diversity technique is applied to the system to overcome multi-cell interference. Due to non orthogonality of spreading codes multi-cell interference is not completely eradicated. To overcome this problem, space time block code (STBC) based space time trellis code (STTC) site diversity technique was introduced to reduce multi-cell interference. In this paper, balanced STTC (B-STTC) based STBC site diversity is proposed to further improve the performance of MC-CDMA system by mitigating multi-cell interference and is extended to STBC based B-STTC site diversity technique. Simulation result shows that STBC based B-STTC site diversity outperforms B-STTC based STBC site diversity technique.

Research on the Strategy of Nodes Cooperative Transmission in Wireless Sensor Networks

The correlation techniques of nodes cooperative transmission strategy in wireless sensor networks with virtual MIMO are presented. A communication model between clusters is proposed. From it, we can see the correlation techniques include coding, forwarding, combining and decoding. The coding is generally divided into three categories: Layered Space-Time Coding, Space-Time Trellis Coding and Space-Time Block Coding. Forwarding can be broken down into Amplifying Forwarding, Decode Forwarding, and Selecting Dynamic Relay. Select combining, equal gain combining and maximum ratio combining are the common combine methods. The decode method is maximum likelihood algorithm.

Improved Super-Orthogonal Space-time Trellis Coded MIMO-OFDM System

In this paper, we propose two full rate space-time coding schemes for multiple-in multiple-out (MIMO) orthogonal frequency division multiplexing (OFDM) systems. The first proposal called extended super-orthogonal space-time code is designed based on constellation rotation for two transmit antennas. The second proposal called super-quasi orthogonal space-time trellis code combines quasi-orthogonal space-time block code with trellis code to provide full rate code for four transmit antennas. The designed space-time coded MIMO-OFDM systems achieve high diversity order with high coding gain by exploiting the diversity advantage of frequency selective fading channels.

Adaptive Generator Sequence Selection in Multilevel Space–Time Trellis Codes

It has been shown that multilevel space–time trellis codes (MLSTTCs) designed by combining multilevel coding (MLC) with space–time trellis codes (STTCs) can provide improvement in diversity gain and coding gain of the STTCs. MLSTTCs assume perfect channel state information (CSI) at receiver and no knowledge of CSI at transmitter. Weighted multilevel space–time trellis codes (WMLSTTCs), designed by combining MLSTTCs and perfect CSI at transmitter are capable of providing improvement in coding gain of MLSTTCs. In this paper, we present improvement in performance of MLSTTCs by using channel feedback information from the receiver for adaptive selection of generator sequences. The selected generator sequences are used for encoding the component STTCs. The receiver compares current channel profile at receiver with a set of predetermined channel profiles, and sends an index of a predefined channel profile closest to the current channel profile to the transmitter. The transmitter selects a code set that matches best with the current channel profile at receiver using the index. The selected code set having different sets of generator sequences is used by STTC encoders to generate dynamic space–time trellis codes (DSTTCs). The DSTTCs act as component codes in multilevel coding for generating new codes henceforth referred to as multilevel dynamic space–time trellis codes (MLDSTTCs). Analysis and simulation results show that MLDSTTCs provide improvement in performance over MLSTTCs.

Space–Time Trellis Codes for Two-Way Relay MIMO Channels With Single-Antenna Relay Nodes

In this paper, the analysis and design of space-time trellis codes (STTCs) for two-way relay channels (TWRCs) with multiantenna source and destination and single-antenna relay nodes, assuming perfect channel state information (CSI) at the destination nodes, is considered. We derive a pairwise error probability (PEP) expression for the performance of STTCs in this type of channels. A simple upper bound on the PEP is then derived and used to find optimum STTCs. We prove that the designed STTCs based on the derived criterion achieve full diversity and significant coding gain in TWRCs, particularly at high signal-to-noise ratios (SNRs).

SUPER ORTHOGONAL SPACE TIME TRELLIS CODES OVER NAKAGAMI FADING MODEL

Performance evaluation of super orthogonal space-time trellis codes for non-frequency selective fading channels & frequency selective fading channels. The analysis is done in presence of fast fading, block fading and quasi-static fading in Rayleigh, and Nakhagami fast fading channels along with comparison. While providing full diversity and full rate, the structure of our new codes allows an increase in the coding gain. Not only does our new SOSTTC outperform the space-time trellis codes in the literature, but it also provides a systematic method for designing space time trellis codes at different rates and for different trellises. Since we have used orthogonal designs as the building blocks in our new SOSTTCs, the complexity of the decoding remains low while full diversity is guaranteed. Codes operating at different rates, up to the highest theoretically possible rate, for different number of states, can be designed by using our optimal set partitioning. In general, new SOSTTCs can provide a tradeoff between rate and coding gain while achieving full diversity.

A Simple Analytical Design Approach to Space Time Trellis Codes

The space time trellis code (STTC) is a combined design of error-control coding, modulation and transmit-receive diversity that improves data rate and error performance in a wireless channel without any loss in spectral efficiency. It can either be described by a graphical representation, or, in terms of closed analytical forms that lead to a more tractable generator matrix description. However, the main difficulty in generating best code is the long search duration which makes both trellis implementation and generator matrix description difficult, thereby, limiting the use of STTC in wireless links. Since an exhaustive search over all the matrix entries turns out to be impractical if the number of transmitter, encoder states and/or constellation size is very high, some literature provide techniques to reduce the search complexity. Some of them are sub-optimal, some are good. However, none reports any straightforward rule of thumb to design the generator matrix. In this paper, we propose two very simple rules to construct the generator matrix for designing STTC with any arbitrary number of transmit antennas and any memory-less constellation. Mathematical justification behind the rules has been presented. It has been shown that the simplicity of proposed rules reduces the code search complexity to a large extent along with a similar or better coding gain compared to those presented in previous literature. In addition, the STTCs obtained from proposed rules perform no worse than the codes given in previous literature in terms of error rate.