We propose a high-speed and low-complexity architecture for the very large-scale integration (VLSI) implementation of the maximum a posteriori probability (MAP) algorithm suited to the double binary turbo decoder. For this purpose, equation manipulations on the conventional Linear-Log-MAP algorithm and architectural optimization are proposed. It is shown by synthesized simulations that the proposed architecture improves speed, area and power compared with the state-of-the-art Linear-Log-MAP architecture. It is also observed that the proposed architecture shows good overall performance in terms of error correction capability as well as decoder hardware's speed, complexity and throughput.

We propose an incremental redundancy (IR)-hybrid ARQ (HARQ) scheme which uses double binary turbo codes for error correction. The proposed HARQ scheme provides a higher throughput at all Es/N0 than the binary turbo IR-HARQ scheme. An extra coding gain is also attained by using the proposed HARQ scheme over turbo codes only.

The IEEE 802.16e standard adopts a power-saving mode (PSM) with a truncated binary exponent (TBE) algorithm for determining sleep intervals. Although the TBE algorithm allows more flexibility in determining sleep intervals, it does not consider the network delay of a response packet. In this letter, we suggest PSM that is based on the conditional probability density function (c-pdf) for the response packet's arrival time at the base station (BS). The proposed algorithm determines sleep interval placement so that the response packet may arrive at the BS during each sleep interval with the same conditional probability. The results show that the proposed algorithm outperforms the TBE algorithm with respect to the packet-buffering delay in the BS and the energy consumption of a mobile station (MS).

A novel turbo coded modulation scheme, called the turbo-APPM, for deep space optical communications is proposed. The proposed turbo-APPM is a serial concatenation of turbo codes, an accumulator and a pulse position modulation (PPM), where turbo codes act as an outer code while the accumulator and the PPM act together as an inner code. The generator polynomial and the puncturing rule for generating turbo codes are chosen to lower the bit error rate. At the receiver, the joint iterative decoding is performed between the inner decoder and the outer turbo decoder. In the outer decoder, local iterative decoding for turbo codes is conducted. Simulation results are presented showing that the proposed turbo-APPM outperforms all previously proposed schemes such as LDPC-APPM, RS-PPM and SCPPM reported in the literature.

In this paper, it is shown that the bit erasure probability of turbo codes with iterative decoding in the waterfall region is nonlinearly scaled by the information blocklength. This result can be used to predict efficiently the bit erasure probability of the finite-length turbo codes over the binary erasure channel.

A new high-throughput turbo decoding scheme adopting double flow, sliding window and shuffled decoding is proposed. Analytical and numerical results show that the proposed scheme requires low number of clock cycles and small memory size to achieve a BER performance equivalent to those of existing schemes.

In this paper, we define a stopping set of turbo codes with the iterative decoding in the binary erasure channel. Based on the stopping set analysis, we study the block and bit erasure probabilities of turbo codes and the performance degradation of the iterative decoding against the maximum-likelihood decoding. The error floor performance of turbo codes with the iterative decoding is dominated by the small stopping sets. The performance degradation of the iterative decoding is negligible in the error floor region, so the error floor performance is asymptotically dominated by the low weight codewords.

Group device-to-device (GD2D) communication is a good solution for data dissemination to devices in proximity without imposing a heavy load on cellular networks. We propose an operating strategy for GD2D communication regarding the mode selection and the power allocation in order to maximize the sum rate of the overall system satisfying QoS requirements of both cellular and D2D links. We derive the maximum sum rate for each class of distance profile of participating devices in the interference-dominant scenario. Using the result, the operating strategy of GD2D communication can be determined in a table-look-up manner.

A novel cooperative spectrum sensing scheme suitable for wireless cognitive radio system with imperfect reporting channels is proposed. In the proposed scheme, binary local decision bits are transmitted to the fusion center and combined to form a soft-valued decision statistics in the fusion center. To form a decision statistics, a majority-decision-aided weighting rule is proposed. The proposed scheme provides a reliable sensing capability even with poor reporting channels.

The convergence behavior of turbo APPM (TAPPM) decoding is analyzed by using a three-dimensional extrinsic information transfer (EXIT) chart and the decoding trajectory. The signal-to-noise ratio (SNR) threshold, below which iterative decoding fails to converge, is predicted by using the 3-D EXIT chart analysis. Bit error rate performances of TAPPM schemes validate the EXIT-chart-based SNR threshold predictions. Outer constituent codes of TAPPM are chosen to show the lowest SNR threshold with the aid of EXIT chart analysis.

We propose a 2Nr MIMO ARQ scheme that uses multi-strata space-time codes composed of two layers. The phase and transmit power of each layer are assigned adaptively at each transmission round to mitigate the inter-layer interference and improve the block error rate by retransmission. Simulation results show that the proposed scheme achieves better performance than the conventional schemes in terms of the throughput and the block error rate.