Superposition coded modulation (original) (raw)

Performance analysis of superposition coded modulation

Physical Communication, 2010

This paper presents a comprehensive analysis of superposition coded modulation (SCM). Two types of SCM schemes, i.e., the single-code SCM (SC-SCM) and multi-code SCM (MC-SCM), are analyzed. The basic features of SCM are described, followed by the information-theoretic analysis. Different encoding/decoding strategies are compared from the capacity point of view. A semi-analytical evolution technique is proposed to track the convergence

Coded modulation using superimposed binary codes

IEEE Transactions on Information Theory, 2004

In this correspondence, we investigate in a comprehensive fashion a one-layer coding/shaping scheme resembling a perfectly cooperated multiple-access system. At the transmitter, binary data are encoded by either single-level or multilevel codes. The coded bits are first randomly interleaved and then entered into a signal mapper. At each time, the signal mapper accepts as input multiple binary digits and delivers as output an amplitude signal, where the input are first independently mapped into 2-PAM signals (possibly having different amplitudes) and then superimposed to form the output. The receiver consists of an iterative decoding/demapping algorithm with an entropy-based stopping criterion. In the special cases when all the 2-PAM signals have equal amplitudes, based on an irregular trellis, we propose an optimal soft-input-soft-output (SISO) demapping algorithm with quadratic rather than exponential complexity. In the general cases, when multilevel codes are employed, we propose power-allocation strategies to facilitate the iterative decoding/dempaping algorithm. Using the unequal power-allocations and the Gaussian-approximation-based suboptimal demapping algorithm (with linear complexity), coded modulation with high bandwidth efficiency can be implemented.

Combined coding and modulation: theory and applications

IEEE Transactions on Information Theory, 1988

It is known that channel encoding, combined with a modulator which uses a redundant set of channel symbols, can significantly increase the performance of multilevel digital transmission systems without requiring more bandwidth or reducing the data rate. First, the theoretical aspects of the encoding process are investigated, resulting in a precise definition of linear codes together with theorems that clarify how linear codes can be obtained. A particular subset of linear codes, called "superlinear codes,'' for which the performance analysis is highly simplified is then identified. n e most relevant performance measures for the analysis of this class of codes are then discussed. The minimum Euclidean distance and the event and bit error probabilities are found analytically through the exploitation of the uniform error property (when applicable) or variations on it. This yields accurate upper and lower bounds to the error rate at the price of reasonable computational complexity. T h theory is then applied to the search for "good" codes and to their performance evaluation. The cases of 16-and 32PSK codes, which are good candidates for use in digital satellite transmission, are considered. Several new results in terms of error event and bit error probabilities are presented, showing considerable gains in terms of SNR with respect to the uncoded case.

Coding and Modulation for Spectral Efficient Transmission

2010

We investigate channel coding and modulation for bandwidth-efficient transmission. For the bit-interleaved coded modulation (BICM) system, we optimize mappings for quadrature amplitude modulation with respect to the resulting symbol and bit error rates at the demapper, and to the achievable BICM and signal set capacities. Further, we design mappings that are most suited for receivers, which exchange information between demapper and decoder in an iterative manner. The mappings are not restricted to certain symbol alphabets, and thus, the optimized mappings outperform similar state-of-the-art schemes. For multi-antenna systems, we examine multidimensional mappings as a means to minimize bit error rates at an iterative receiver. Finally, we derive for block codes over the binary erasure channel closed-form expressions for their transfer characteristics to be used in the extrinsic information transfer chart. Based on that, capacity approaching irregular, i.e., time-varying, codes are su...

Broadcast Coded Modulation: Multilevel and Bit-Interleaved Construction

IEEE Transactions on Communications, 2017

The capacity of the AWGN broadcast channel is achieved by superposition coding, but superposition of individual coded modulations expands the modulation alphabet and distorts its configuration. Hierarchical modulations, which appear in the literature mostly in the context of unequal error protection, can approach only a few isolated points on the boundary of the broadcast capacity region. This paper studies multilevel coding (MLC) for constellation-constrained broadcast coded modulation. The conditions under which multilevel codes can achieve the constellation-constrained capacity of the AWGN broadcast channel are derived. We propose a pragmatic multilevel design technique with near-constellation-constrained-capacity performance where the coupling of the superposition inner and outer codes are localized to each bit-level. It is shown that this can be further relaxed to a code coupling on only one bit-level, with little or no penalty under natural labeling. The rate allocation problem between the bit levels of the two users is studied and a pragmatic method is proposed, again with near-capacity performance. In further pursuit of lower complexity, a hybrid MLC-BICM is proposed, whose performance is shown to be very close to the boundary of the constellation-constrained capacity region. Simulation results show that good point-to-point LDPC codes produce excellent performance in the proposed coded modulation framework.

Generalized Code Index Modulation Technique for High Data Rate Communication Systems

IEEE Transactions on Vehicular Technology, 2015

In this paper, we propose a generalized code index modulation (CIM) technique for direct sequence-spread spectrum (DS-SS) communication. In particular, at the transmitter, the bit stream is divided into blocks in which each block is divided into two sub-blocks, named as mapped and modulated sub-block. Thereafter, the bits within the mapped sub-block are used to select one of the predefined spreading codes, which is then used to spread the modulated bits of the second sub-block. In this design, the use of the spreading code index as an information-bearing unit increases the overall spectral efficiency of this system. At the receiver side, the spreading code index is first estimated, thus resulting in a direct estimation of mapped sub-block bits. Consequently, the corresponding spreading code to this estimated index is used to de-spread the modulated symbol of the modulated sub-block. Subsequently, mathematical expressions for bit error rate, symbol error rate, throughput, energy efficiency, and the system complexity are derived to analyze the system performance. Finally, simulation results show that the proposed modulation scheme can achieve higher data rate than the conventional DS-SS system, with lower energy consumption and complexity.

Concatenated multilevel block coded modulation

IEEE Transactions on Communications, 1993

Abstruct-Encoding and decoding schemes for concatenated multilevel block codes are presented. By one of these structures, a real coding gain of 5.6-7.4 dB for the bit error range of lop6lo-' is achieved for transmission through the additive white Gaussian noise channel. Also, a rather large asymptotic coding gain is obtained. The new coding schemes have very low decoding complexity and increased coding gain in comparison with the conventional block and trellis coded modulation structures. A few design rules for concatenated (single and) multilevel block codes with large coding gain are also provided.

Bit-Interleaved Coded Modulation

IEEE Transactions on Information Theory, 1998

The principle of coding in the signal space follows directly from Shannon's analysis of waveform Gaussian channels subject to an input constraint. The early design of communication systems focused separately on modulation, namely signal design and detection, and error correcting codes, which deal with errors introduced at the demodulator of the underlying waveform channel. The correct perspective of signalspace coding, although never out of sight of information theorists, was brought back into the focus of coding theorists and system designers by Imai's and Ungerböck's pioneering work on coded modulation. More recently, powerful families of binary codes with a good tradeoff between performance and decoding complexity have been (re-) discovered. Bit-Interleaved Coded Modulation (BICM) is a pragmatic approach combining the best out of both worlds: it takes advantage of the signal-space coding perspective, whilst allowing for the use of powerful families of binary codes with virtually any modulation format.

A pragmatic approach to trellis-coded modulation

IEEE Communications Magazine, 1989

Forward Error Correcting (FEC) coding is a practical technique for increasing the transmission efficiency of virtually all digital communication channels. whatever their power or bandwidth limitations. Efficiency then applies to both the power and the bandwidth required to support a given information rate. or conversely to increase the information rate to be transmitted with a given power and bandwidth. This realization of the universal merits of FEC coding is relatively recent. When practical coding techniques were first proposed in the late sixties,' it was generally believed that coding would benefit only power-limited channels where bandwidth was plentiful. Thus. the first applications were to space applications for which data rates, limited by low on-board transmitter power and large range losses, were much smaller than the available bandwidth. The first practical codes employed code rates of I / ? or even 1/3, which equated to less than 1 b/s/Hz with Quadrature Phase Shift Keying (QPSK).

Multistage decoding of multilevel block M-PSK modulation codes and its performance analysis

IEEE Transactions on Information Theory, 1993

Abstruct-l'he multilevel coding method proposed by Imai and Hirakawa is a powerful technique for constructing bandwidth efficient block modulation codes systematically with arbitran@ large minimum squared Euclidean d h n c e from component codes in coqjunction with proper bits-to-signal mapping. The multilevel modulation codes constructed by this method allow the use of multistage decoding procedures that provide good tradeoff between performance and decoding complexity. Multistage decoding of multilevel block M-PSK modulation codes for the AWGN channel is investigated. Several types of multiitage decoding, including a suboptimum soft-decision decoding scheme, are devised and analyzed. Upper bounds on the probability of an incorrect decodipg of a code are derived for the proposed multistage decoding schemes. Error probabilities of some specific multilevel block 8-PSK modulation codes are evaluated and simulated. The computation and simulation results for these codes show that with multistage decoding, significant coding gains can be achieved with large reduction in decoding complexity. In one example, it is shown that the difference in performance between the proposed suboptimum multistage soft-decision decoding and the single-stage optimum decoding is small, only a fraction of a dB loss in SNR at the block error probability of Index Tenns-Multilevel codes, multistage decoding, suboptimum decoding I. I N T R O D U C T I O N NE of the dramatic developments in bandwidth-efficient 0 communications over the past ten years is the introduction and rapid applications of combined coding and bandwidth efficient modulation, known as coded modulation, for reliable data transmission. Using coded modulation, reliable data transmission can be obtained without compromising bandwidth efficiency. The first coded modulation scheme was introduced by Ungerboeck in 1976 [l], and later published in 1982 [2]. In this scheme, trellis (or convolutional) codes were combined with various types of modulation signal set to form modulation codes by proper bits-to-signal mapping through signal set partitioning. This scheme is now known as trellis-coded modulation (TCM). Since the publication of Ungerboeck's prize winning paper [2], there has been a great deal of research