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In this paper, a differential space-time coding (D-STC) scheme is presented for relay assisted cooperative wireless communication networks over frequency selective fading channels. Two most common schemes, i.e., differential amplify-and-forward (DAF) and differential decode-and-forward (DDF), are both investigated in our single relay assisted system. Leveraging spectral encoder and differential space-time...
In this paper, we are concerned with an asymmetric multiple-access channel (MAC) model with two users, which are distinguished as primary user and secondary user, respectively, according to their mobility. The low-mobility user (primary user) has a time-invariant uplink and employs a single-user code that was originally designed to satisfy a given error performance requirement under the assumption...
Channel conditions on satellite communication systems are changed continuously. The Rate Compatible Punctured Turbo (RCPT) Codes Hybrid Automatic Repeat Request (HARQ) have been shown to improve reliable communications by adapting varying channel conditions. The paper discusses the throughput performance and transmission numbers of three HARQ schemes including partial incremental redundancy (partial-IR)...
This paper compares the performance of a blind relay communication system with that of a non-blind relay communication system. For a blind system, a differential space-time block code (DSTBC) or a blind Viterbi detection is used, and for a non-blind system, a space-time block code (STBC) is used. Also, this paper takes another blind detection mechanism, the Zhang's code, and compares its performance...
Orthogonal Space-Time Block Codes (STBC) with Multiple-Input Multiple-Output (MIMO) systems have become a very popular way of adding spatial diversity to transmissions. Orthogonal Frequency Division Multiplexing (OFDM) is a modulation technique to further increase the robustness against frequency selective fading at high data rates. Some authors have then proposed to combine both: linear STBC codes...
A scaling technique is proposed to maintain the decoding failure probability of Vector Symbol Decoding (VSD) with the increase in data rate. Specifically, the symbol size must be increased in the same ratio as the data rate. VSD is attractive since it allows for a very flexible scaling. This paper also presents a way to compute the optimal maximum number of syndromes to minimize the complexity of...
This paper presents S-Random interleaver based Interleave Division Multiple Access (IDMA) scheme. S-Random interleaver provides good spreading parameter which produce less correlated extrinsic values and also lowers down the error floor, hence better the system performance. As interleavers in IDMA used to recognize the different signal from the different users, S-Random interleavers are employed in...
Asymmetric Distributed Source-Channel coding (DSC) is considered, where a pair of correlated sources are transmitting to a central node. The distributed scheme is based on Turbo Trellis Coded Modulation (TTCM), where the first source will be channel encoded and then compressed before it is sent over Nakagami-m fading channels. The second source signal, however, is assumed to be available flawlessly...
This paper considers the capacity limit of an uplink wideband CDMA system. In order to make the studied results useful for the performance assessment of real cellular networks, various realistic assumptions are included in the problem. An equivalent discrete-time channel model is derived based on sufficient statistic for optimal decoding of transmit messages. The capacity regions are then characterized...
Turbo codec in 3GPP LTE standard is implemented in an existing Rayleigh fading channel. Its bit error rate (BER) performance is gauged. The research is investigated to compare the performance of turbo codes with traditional Quadratic Permutation Polynomial (QPP) interleaver and comparatively simpler matrix interleaver in Rayleigh flat fading channel. The simulation outcome reveals that the BER performance...
We consider the joint source-channel coding (JSCC) problem where the real valued outputs of two correlated memoryless Gaussian sources are scalar quantized, bit assigned, and transmitted, without applying any error correcting code, over a multiple access channel (MAC) which consists of two orthogonal point-to- point time-correlated Rayleigh fading sub-channels with soft- decision demodulation. At...
The objective of this paper is to study and analyze the suitability of Luby Transform (LT) codes for fading channels such as Rayleigh and Rician channels. The performance of LT codes is actually governed by a well-defined degree distribution function used in LT process. Hence, this paper presents a novel approach called Modified Degree Distribution (MDD) for improving the delay and Bit Error Rate...
In this paper, we carry out a unified performance analysis of hybrid automatic repeat request (HARQ) with incremental redundancy (IR) from an information theoretic perspective over a point-to-point free-space optical (FSO) system. First, we introduce a novel unified expression for the distribution of a single FSO link modeled by the Gamma fading that accounts for pointing errors subject to both types...
We consider a cooperative relay communication system where the source and the relay have separate frequency bands for message transmission. The relay is assumed to be a decode-forward node, i.e. It can decode the information send from the source node and re-transmit after suitable modifications. With power splitting at the source, we find an optimum relaying function which achieves the capacity of...
In this paper, we present the results of using a turbo decoder to retrieve a serially encoded data stream, which has been transmitted over an aeronautical channel. The transmitted data streams are Double Differential Phase Shift Keying (DDPSK) modulated signals, which are encoded using two rate one-half (1/2) recursive systematic convolutional (RSC) encoders, and then transmitted over the channel...
In this paper, compute-and-forward physical layer network coding (PNC) scheme is investigated for wireless two-way relay channel. The achievable rates are reviewed both for AWGN channel and fading channel. New transmit schemes by using channel inversion precoding are proposed over fading channel to achieve much higher rates. It is revealed that with the proposed channel aware precoding scheme, the...
In this paper, various physical layer network coding (PNC) schemes are revisited for wireless two-way relay channel in single antenna case. The achievable rates are reviewed for AWGN channel and newly derived for fading channel for all these PNC schemes employing lattice codes and lattice decoding. A new transmit scheme using precoding is proposed over fading channel to achieve higher rates. It is...
This paper proposes a two dimensional (2D) code, which has vertical raptor-like rate-compatible LDPC code and horizontal Reed Solomon (RS) code, for the terrestrial CTxn system. The proposed 2D code not only removes error-floor phenomenon with a help of RS code, but also does not require a complex interleaver for stable reception under fading channels because the 2D code itself provides block-type...
Mobile devices or sensor nodes are usually energy-constrained, and in some scenarios it is inconvenient or impractical to charge or replace batteries. To tackle this problem, the idea of transferring power to mobile devices wirelessly via radio frequency signals has recently gained much attention. In this paper, we consider a point-to-point communication system in which the transferred power is used...
Secure transmission between two agents, Alice and Bob, over block fading channels can be achieved similarly to conventional hybrid automatic repeat request (HARQ) by letting Alice transmit multiple blocks, each containing an encoded version of the secret message, until Bob informs Alice about successful decoding by a public error-free return channel. In existing literature each block is a differently...
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