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This paper discusses the contemporary problem of providing multiple-access (MAC) to a massive number of uncoordinated users. First, we define a random-access code for Ka-user Gaussian MAC to be a collection of norm-constrained vectors such that the noisy sum of any Ka of them can be decoded with a given (suitably defined) probability of error. An achievability bound for such codes is proposed and...
Two classes of perfect codes for single balanced adjacent deletions (BADs) are provided. These classes are inspired by Levenshtein's work on binary perfect codes for single standard deletions. One of the classes is defined via inversion numbers and the other is defined via Levenshtein codes. The first half of this paper is devoted to the proof of perfectness and the second half is devoted to discussion...
Write-once memory (WOM) is a storage device consisting of binary cells which can only increase their levels. A t-write WOM code is a coding scheme which allows to write t times to the WOM without decreasing the levels of the cells. The sum-rate of a WOM code is the ratio between the total number of bits written to the memory and the number of cells. It is known that the maximum sum-rate of a t-write...
This paper Introduces the discrete memoryless multiple access wiretap channel with noiseless cribbing, where the cribbing may be either causal or strictly causal. We derive lower bounds for secrecy rates for both causal and strictly causal cribbing under either a decode-forward or partial-decode-forward strategy. Our results recover the achievable rate regions of the MAC wiretap and MAC with cribbing,...
Binary AIFV codes, which can attain better compression rate than Huffman codes, uses two code trees that may have incomplete internal nodes, and source symbols are assigned to some internal nodes in addition to leaves. Although the code trees of Huffman codes, which are full binary trees, are well studied, the AIFV code trees have not been yet studied in detail. In this paper, we show that there exists...
It is now well known that using a long and complicated error correcting code (ECC) designed for the worst-case error probability requirement wastes excessive total system energy (transmit + circuit energy) when the error probability requirement is much higher than the worst case. We propose a novel adaptive polar coding strategy that adjusts the decoder circuit to consume minimal decoding circuit...
A concatenated coding scheme using a polarization transformation followed by outer sub-codes is analyzed. Achievable error exponents and upper bounds on the error rate are derived. The first bound is obtained using outer codes which are typical linear codes from the ensemble of parity check matrices whose elements are chosen independently and uniformly. As a byproduct of this bound, it determines...
The K-user discrete memoryless (DM) broadcast channel (BC) with two degraded messages, with one common message to be decoded by all receivers and a private message by a subset of receivers, is studied. The receivers that must decode both messages are referred to as private receivers and the remaining ones that need only decode the common message as common receivers. We obtain two main results. The...
LT codes are a class of rateless codes designed for data dissemination on erasure channels. In this paper, we present a decoder for LT codes on partial erasure channels, which were recently introduced for multi-level read storage channel applications. We compare the efficiency of LT codes on these channels to those on the q-ary Erasure Channel (QEC).
The extremely strict code length constraint is the main drawback of lowest density, maximum-distance separable (MDS) array codes of distance greater than 3. To break away from the status quo, we proposed in [5] a family of lowest density MDS array codes of (column) distance 4, called XI-Code. Compared with the previous alternatives, XI-Code has lower encoding and decoding complexities, and much looser...
The capacity region of 1-to-K broadcast packet erasure channels with ACK/NACK is known for some scenarios, e.g., K ≤ 3, etc. However, existing achievability schemes either require knowing the target rate R in advance, and/or have a complicated description of the achievable rate region that is difficult prove whether it matches the capacity or not. This work proposes a new network coding protocol with...
We investigate the maximum coding rate achievable on a two-user broadcast channel for the case where a common-message is transmitted using fixed-blocklength codes with feedback. Specifically, we focus on a family of broadcast channels composed of two antisymmetric Z-channels. For this setup, we obtain matching upper and lower bounds on the dispersion term in the asymptotic expansion of the maximum...
We establish new capacity bounds for the multi-sender unicast index-coding problem. We first revisit existing bounds proposed by Sadeghi et al. and identify the suboptimality of their inner bounds in general. We then present a simplified version of the existing multi-sender maximal-acyclic-induced-subgraph outer bound. For the inner bound, we propose joint link-and-sender partitioning to replace sender...
We develop a random binning scheme for strong coordination in a network of two nodes separated by a noisy channel, in which the input and output signals have to be coordinated with the source and its reconstruction. In the case of non-causal encoding and decoding, we propose a joint source-channel coding scheme and develop inner and outer bounds for the strong coordination region. While the set of...
We consider the problem of constructing codes that can correct δ deletions occurring in an arbitrary binary string of length n bits. Varshamov-Tenengolts (VT) codes can correct all possible single deletions (δ = 1) with an asymptotically optimal redundancy. Finding similar codes for δ ≥ 2 deletions is an open problem. We propose a new family of codes, that we call Guess & Check (GC) codes, that...
The second-order behavior of the discrete memoryless arbitrarily-varying channel is considered in the fixed error regime when the encoder and decoder share randomness that is independent from the adversarial choice of state. The dispersion (coefficient of the second-order term) is exactly characterized for most channels of interest when infinite shared randomness is allowed, and it is shown that precisely...
We analyze the problem of secure communication over a wiretap channel with an active adversary, in which the legitimate transmitter has the opportunity to sense and learn the adversary's actions. Specifically, the adversary has the ability to switch between two channels and to observe the corresponding output at every channel use; the encoder, however, has causal access to observations impacted by...
Compression of multispectal images is of great importance in an environment where resources such as computational power and memory are scarce. To that end, we propose a new extremely low-complexity encoding approach for compression of multispectral images, that shifts the complexity to the decoding. Our method combines principles from compressed sensing and distributed source coding. Specifically,...
A general inner bound is given for the discrete memoryless broadcast channel with an arbitrary number of users and general message sets, a setting that accounts for the most general form of concurrent groupcasting, with up to exponentially many messages intended for any set of subsets of receivers. Achievability is based on superposition coding and rate-splitting, where each receiver jointly decodes...
We study a setting where two source streams with different decoding deadlines must be transmitted over a burst erasure channel. The source streams are multiplexed into a single stream of channel-packets at the encoder and transmitted over a packet erasure channel. The decoder must recover the source-packets within each stream sequentially, by their corresponding deadlines. We consider the burst-erasure...
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