A double serially concatenated code with two interleaves consists of the cascade of an outer encoder, an interleaver permuting the outer codeword bits, a middle encoder, another interleaver permuting the middle codeword bits and an inner encoder whose input words are the permuted middle codewords. The construction can be generalized to h cascaded encoders separated by h – 1 interleavers, where ...

| A tutorial introduction to the new class of binary parallel concatenated recursive systematic convolutional codes termed turbo codes is presented. It is shown that such codes are in fact linear block codes, and the encoding operation can be viewed as a modulo-2 multiplication of the information sequence with a generator matrix. A framework for analyzing the performance of turbo codes is propo...

This paper analyzes an ARQ scheme using parity retransmissions. By dividing each transmission block into sub­ blocks, the combination of a transmission block and its retrans­ mission block has the structure of a concatenated code. We derive formulae for calculating an upper bound on the probability of undetected errors and a lower bound on the throughput for such an ARQ scheme. Numerical result...

Spatial coupling of individual LDPC codes improves the BP threshold of the coupled ensemble to the MAP threshold of the underlying ensemble. In this report, we investigate the performance of spatial coupling on LDGM codes which might lead to constructing a new class of rateless codes. In what follows, we study Raptor codes as a class of rateless codes and investigate spatial coupling on LDPC en...

Time-varying codes associate variable length code words to letters being encoded depending on their positions in the input string. These codes have been introduced in [8] as a proper extension of L-codes. This paper is devoted to a further study of time-varying codes. First, we show that adaptive Huffman encodings are special cases of encodings by time-varying codes. Then, we focus on three kin...

Future wireless communication systems are characterized by heterogeneity in terms of node capabilities, link level requirements, propagation environments, cell designs and subnet structures. High carrier frequencies and large system bandwidth will make extreme diversity factors feasible. This imposes new requirements on space-time codes. In this paper we present a new concatenated linear space-...

We give a general method to construct MDS one-dimensional convolutional codes. Our method generalizes previous constructions [5]. Moreover we give a classification of one-dimensional Convolutional Goppa Codes and propose a characterization of MDS codes of this type. Introduction One of the main problems in coding theory is the construction of codes with a large distance, such as so-called MDS c...

An erasure code is said to be a code with sequential recovery with parameters r and t, if for any s ≤ t erased code symbols, there is an s-step recovery process in which at each step we recover exactly one erased code symbol by contacting at most r other code symbols. In earlier work by the same authors, presented at ISIT 2017, we had given a construction for binary codes with sequential recove...

2-dimensional (2D) block spread CDMA achieves multiple-access interference (MAI) free uplink transmission while using low-complexity single-user detection. An important problem is how efficiently to assign the limited resource of spreading codes to users. In this paper, we propose a code assignment algorithm for the uplink of a 2D block spread CDMA cellular system. It is confirmed by the comput...