Ronald Y. S. Tee

Turbo Coding, Turbo Equalisation and Space-Time Coding: EXIT-Chart-Aided Near-Capacity Designs for Wireless Channels

Covering the full range of channel codes from the most conventional through to the most advanced, the second edition of Turbo Coding, Turbo Equalisation and Space-Time Coding is a self-contained reference on channel coding for wireless channels. The book commences with a historical perspective on the topic, which leads to two basic component codes, convolutional and block codes. It then moves on to turbo codes which exploit iterative decoding by using algorithms, such as the Maximum-A-Posteriori (MAP), Log-MAP and Soft Output Viterbi Algorithm (SOVA), comparing their performance. It also compares Trellis Coded Modulation (TCM), Turbo Trellis Coded Modulation (TTCM), Bit-Interleaved Coded Modulation (BICM) and Iterative BICM (BICM-ID) under various channel conditions.The horizon of the content is then extended to incorporate topics which have found their way into diverse standard systems. These include space-time block and trellis codes, as well as other Multiple-Input Multiple-Output (MIMO) schemes and near-instantaneously Adaptive Quadrature Amplitude Modulation (AQAM). The book also elaborates on turbo equalisation by providing a detailed portrayal of recent advances in partial response modulation schemes using diverse channel codes.A radically new aspect for this second edition is the discussion of multi-level coding and sphere-packing schemes, Extrinsic Information Transfer (EXIT) charts, as well as an introduction to the family of Generalized Low Density Parity Check codes.This new edition includes recent advances in near-capacity turbo-transceivers as well as new sections on multi-level coding schemes and of Generalized Low Density Parity Check codesComparatively studies diverse channel coded and turbo detected systems to give all-inclusive information for researchers, engineers and students Details EXIT-chart based irregular transceiver designs Uses rich performance comparisons as well as diverse near-capacity design examples

EXIT-chart aided near-capacity Irregular Bit-Interleaved Coded Modulation design

A near-capacity irregular bit-interleaved coded modulation based iterative decoding (Ir-BICM-ID) aided scheme is proposed. The irregular design of the scheme pervades the three basic components of BICM-ID, namely the encoder, the unity-rate precoder and the bit-to-symbol mapper. As a result, irregular BICM-ID schemes constituted by irregular components are created, which are capable of approaching the capacity of coded modulation. This is achieved by creating a marginally open extrinsic information transfer (EXIT) chart tunnel, and exploiting the theorem that the open tunnels area is characteristic of how closely the scheme operates to the channels capacity. The proposed Ir-BICM-ID scheme employs irregular convolutional codes (IrCC), irregular unity-rate codes (IrURC) and irregular mappers (IrMapper).

Serially Concatenated Luby Transform Coding and Bit-Interleaved Coded Modulation Using Iteratlive Decoding for the Wireless Internet

In bit-interleaved coded modulation (BICM) the coding and modulation schemes were jointly optimized for the sake of attaining the best possible performance when communicating over fading wireless communication channels. The iterative decoding scheme of BICM (BICM-ID) invoking an appropriate bit-to-symbol mapping strategy enhances its achievable performance in both AWGN and Rayleigh channels. BICM-ID may be conveniently combined with Luby transform (LT) codes, which were designed for handling packetized wireless Internet data traffic in erasure channels without retransmitting the corrupted packets. By jointly designing a serially concatenated LT-BICM-ID code, an infinitesimally low bit error rate (BER) is achieved for signal to noise ratios (SNR) in excess of 7.5 dB over wireless Internet type erasure channels contaminated by AWGN

Reduced-complexity near-capacity downlink iteratively decoded generalized multi-layer space-time coding using irregular convolutional codes

This paper presents a low complexity iteratively detected space-time transmission architecture based on Generalized Multi-Layer Space-Time (GMLST) codes and Irregular Convolutional Codes (IRCCs). The GMLST combines the benefits of the Vertical Bell-Labs LAyered Space-Time (VBLAST) scheme and Space-Time Coding (STC). The GMLST is serially concatenated with a Unity-Rate Code (URC) and an IRCC which are used to facilitate near-capacity operation with the aid of an EXtrinsic Information Transfer (EXIT) chart based design. Reduced-complexity iterative multistage Successive Interference Cancellation (SIC) is employed in the GMLST decoder, instead of the significantly more complex Maximum Likelihood (ML) detection. For the sake of approaching the maximum attainable rate, iterative decoding is invoked to achieve decoding convergence by exchanging extrinsic information across the three serial component decoders. Finally, it is shown that the SIC-based iteratively detected IRCC-URC-GMLST system is capable of providing a feasible trade-off between the affordable computational complexity and the achievable system throughput.

Generalized Low-Density Parity-Check Coding Aided Multilevel Codes

Classic low-density parity-check (LDPC) codes have recently been used as component codes in multilevel coding (MLC) due to their impressive BER performance as well as owing to their flexible coding rates. In this paper, we proposed a multilevel coding invoking generalized low-density parity-check (GLDPC) component codes, which is capable of outperforming the classic LDPC component codes at a reduced decoding latency, when communicating over AWGN and uncorrelated Rayleigh fading channels

Luby Transform Coding Aided Bit-Interleaved Coded Modulation for the Wireless Internet

Bit-Interleaved Coded Modulation using Iterative Decoding (BICM-ID) is amalgamated with Luby Transform (LT) coding. The resultant joint design of the physical and data link layer substantially improves the attainable Bit Error Rate (BER) performance. A Cyclic Redundancy Check (CRC) combined with a novel Log-Likelihood Ratio (LLR) based packet reliability estimation method is proposed for the sake of detecting and disposing of erroneous packets. Subsequently, bit-by-bit LT decoding is proposed, which facilitates a further BER improvement at a lower number of BICM-ID iterations. Finally, we revisit the pseudo random generator function used for designing the LT generator matrix.

Precoder-aided iterative detection assisted multilevel coding and three-dimensional EXIT-chart analysis

A novel three-dimensional (3D) EXIT chart is developed for investigating the iterative behaviour of multilevel coding (MLC) invoking multistage decoding (MSD). The extrinsic information transfer characteristics of both the symbol-to-bit demapper used and those of the different protection constituent decoders suggest that potential improvements can be achieved by appropriately designing the demapper. The proposed 3D EXIT chart is then invoked for studying the precoder-aided multilevel coding scheme employing both MSD and parallel independent decoding (PID) for communicating over AWGN and uncorrelated Rayleigh fading channels with the aid of 8PSK modulation. At BER=10-5, the precoder was capable of enhancing the achievable Eb/N0 performance by 0.5 dB to 2.5 dB over AWGN and Rayleigh channels, respectively

Near-Capacity Irregular Bit-Interleaved Coded Modulation

An irregular bit-interleaved coded modulation based iterative decoding (Ir-BICM-ID) aided scheme is proposed. The irregularity of the scheme pervades the three basic components of BICM-ID, namely the encoder, the unity-rate precoder and the bit-to-symbol mapper. As a result, adaptive BICM-ID schemes constituted by irregular components are created, which are capable of approaching the capacity of coded modulation. This is achieved by creating a narrow extrinsic information transfer (EXIT) chart, using a novel EXIT curve matching algorithm. The proposed Ir-BICM-ID scheme employs irregular convolutional codes (IrCC), irregular unity-rate codes (IrURC) and irregular mappers (IrMapper).

Bit-Interleaved Sphere-Packing-Aided Iteratively Detected Space-Time Coded Modulation

We design a bit-interleaved space-time coded modulation scheme using iterative decoding (BI-STCM-ID) combined with a new multidimensional mapping scheme invoking sphere-packing (SP) modulation, which we refer to as the space-time block-coded sphere-packed bit-interleaved coded modulation (STBC-SP-BICM) arrangement. The binary switching algorithm (BSA) is used to optimize the cost function employed for deriving different mapping strategies, which are designed with the aid of EXtrinsic Information Transfer (EXIT) charts for the sake of improving the convergence behavior of the system. The resultant system is amalgamated with a unity-rate code (URC) as a precoder to enhance the attainable iterative detection performance. An irregular URC (IrURC) is invoked to create an open EXIT tunnel at low signal-to-noise ratios (SNRs). The complexity of employing the multidimensional SP scheme is also addressed.

Downlink Steered Space-Time Spreading Assisted Generalised Multicarrier DS-CDMA Using Sphere-Packing-Aided Multilevel Coding

This paper presents a novel generalised Multi-Carrier Direct Sequence Code Division Multiple Access (MC DS-CDMA) system invoking smart antennas for improving the achievable performance in the downlink, as well as employing multi-dimensional Sphere Packing (SP) modulation for increasing the achievable diversity product. In this contribution, the MC DS-CDMA transmitter considered employs multiple Antenna Arrays (AA) and each of the AAs consists of several antenna elements. Furthermore, the proposed system employs both time- and frequency- (TF) domain spreading for extending the achievable capacity, when combined with a novel user-grouping technique for reducing the effects of Multiuser Interference (MUI). Moreover, in order to further enhance the systems performance, we invoke a MultiLevel Coding (MLC) scheme, whose component codes are determined using the so-called equivalent capacity based constituent-code rate-calculation procedure invoking a 4-dimensional bit-to-SP-symbol mapping scheme. Our results demonstrate an approximately 3.8 dB Eb/N0 gain over an identical throughput scheme dispensing with SP modulation at a BER of 10-5.