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A novel algorithm for adaptive video transmission over wireless fading channels is presented. The algorithm is intended for transmission over channels for which the channel coherence interval is shorter than the duration of a video frame and the transmitter has knowledge of the channel state at the time of transmission of each packet. The probability density function (pdf) of the number of the obtainable...
In this paper, we propose a new path metric, which improves the performance of soft-input soft-output (SISO) tree detection for iterative detection and decoding (IDD) systems. While the conventional path metric accounts for the contribution of symbols on a visited path due to the causal nature of tree search, the new path metric, called improved path metric, reflect the contribution of unvisited paths...
This paper presents the implementation result of List-of-2 soft-decision Viterbi decoder on FPGA platform. It was to be used as the inner decoder of a special designed concatenated code, of which the outer decoder is Vector Symbol Decoder (VSD). Since list-of-2 Viterbi was not the final decoding stage, it was not required to provide low decoding failure probability. Therefore, only a small list of...
It is well known that in general, feedback cannot increase the capacity of a discrete memoryless channel. However, it can help simplify the complexity of encoding and decoding. Schalkwijk and Kailath (1966) developed a class of block codes for Gaussian channels with ideal feedback. They showed that the probability of decoding error decreases as a second-order exponent in block length for rates below...
Consider multiple sensors that transmit data over analog erasure links to an estimation center. The sensors have access to distinct entries of the output vector of a linear and time-invariant plant, and the estimation center is intended to produce state estimates. If the estimation center can transmit noiseless acknowledgements back to the sensors at every time step, optimal algorithms to calculate...
This paper presents a new decoder for probabilistic binary traitor tracing codes which is based on classical hypothesis testing and estimation theory. This new decoder is blind, in the sense of ignoring a priori the collusion attack it is facing. It basically performs a joint estimation of the collusion channel and the probability that each user takes part in the collusion. The experimental results...
This paper investigates the minimum data rate over a lossy channel for the mean square stabilization of single input discrete linear time-invariant (LTI) systems. The channel is subject to a packet dropout process, which is modeled as an independent and identically distributed (i.i.d.) process. The minimum data rate, which is explicitly given by unstable eigenvalues of the open loop matrix and the...
In this paper, we mention our work on incorporating rule based reordering and morphological information for English to Malayalam statistical machine translation. The main ideas which have proven very effective are (i) reordering the English source sentence according to Malayalam syntax, and (ii) using the root suffix separation on both English and Malayalam words. The first one is done by applying...
The encoding and decoding of binary LDPC codes are expanded using characteristics of the Finite Fields concept, a nonbinary LDPC code encoding and decoding method based on the Finite Fields are investigated and the computational complexity of this algorithm is estimated, providing a foundation for the practical applications of this method. Then this algorithm is compared with the binary algorithm...
Hierarchical phrase-based translation model has been proven to be a simple and powerful machine translation model. However, due to the computational complexity constraints, the extraction and use of hierarchical rules are usually restricted under certain limits, and these limits could have a negative impact on the performance of the translation model, especially for reordering. This paper presents...
Exact statistics of the local signal-to-noise ratios (SNRs) of the best relay in decode-and-forward (DF) opportunistic relaying (ORe) are derived. It is observed that although the different links are assumed to suffer independent fadings, the best-relay local SNRs are dependent. Both joint and marginal statistics are determined for the general case of nonidentical SNR distributions, and a source-relay-symmetric...
In this paper, we analyze the performance of cooperative diversity wireless networks using amplify-and-forward (AF) or decode-and-forward (DF) relaying over independent, non-identically distributed Nakagami-m fading channels. We derive the symbol error probability (SEP) using the moment generating function (MGF) of the end-to-end signal-to-noise-ratio (SNR) at the destination. In AF relaying, and...
It has been shown that, under belief-propagation (BP) decoding, random-coset GF(q) low-density parity-check (LDPC) codes and irregular repeat-accumulate (IRA) codes with q-ary nonuniform signal constellations approach the unrestricted Shannon limit. Extrinsic information transfer (EXIT) charts are employed in the design of random-coset GF(q) LDPC and IRA modulation codes. However, in the EXIT charts...
We propose a new family of high-rate space-time block codes called embedded orthogonal space-time (EOS) codes. The family is parameterized by the number of transmit antennas, which can be any positive integer, and by the rate, which can be as high as half the number of transmit antennas. The proposed codes are based on a new concept called embedding, whereby information symbols of a traditional space-time...
This paper proposes a novel receiver scheme for multiple-input multiple-output (MIMO) systems with hybrid-automatic-retransmission-request (HARQ) mechanism. The proposed scheme improves the decoding performance by characterizing and counteracting uncertainty of the soft decisions. Furthermore, the proposed scheme can make full use of the received signals and especially performs well when the prior...
In this paper, we investigate resource allocation for decode-and-forward (DF) opportunistic cooperative networks, where the availability of the direct link between the source and the destination has been taken into consideration. In addition to separate power allocation and location optimization, we also consider joint resource allocation to minimize the outage probability. Under Rayleigh fading channels,...
In wireless cooperative transmissions, nodes may deviate from the cooperative protocol to reduce energy consumption while still reaping the benefits of other nodes' cooperation. Misbehavior is implemented by refraining from responding to cooperation request, mimicking adverse channel conditions. From time to time (with a given percentage) cooperations requests are accepted in order to avoid being...
In this paper, we focus on a (2,2)-threshold scheme in the presence of an opponent who impersonates one of the two participants. We consider an asymptotic setting where two shares are generated by an encoder blockwisely from an n-tuple of secrets generated from a stationary memoryless source and a uniform random number available only to the encoder. We introduce a notion of correlation level of the...
The main result of this paper is a generic composition theorem for low error two-query probabilistically checkable proofs (PCPs). Prior to this work, composition of PCPs was well-understood only in the constant error regime. Existing composition methods in the low error regime were non-modular (i.e., very much tailored to the specific PCPs that were being composed), resulting in complicated constructions...
In recent years the quadratic program (QP) is applied for the blind signal detection of the time-varying OFDM systems. The minimum solution of the QP could be obtained through the class of the sphere decoder (SD) algorithm, which is equivalent to the tree search approach. In this paper, we derive some formulas describing the probability information about the received signal. With these formulas, a...
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