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In this paper, we present an efficient turbo-coded space time block coding (STBC) schemes in block fading channels. It has been reported that proper utilization of soft decision information is one of the important factors affecting the performance of turbo codes. If a STBC scheme is used with turbo codes, the output of the STBC decoder must be fed into a turbo code decoder in the form of soft decision...
A novel concatenated multi-input multi-output (MIMO) communication system based on time varying linear transformation (TVLT) and Tanner codes is proposed in this paper. The girth 4 property of Tanner codes is discussed briefly. Combined with the outstanding distance property of Tanner codes, TVLT can provide full diversity and maximum coding gain at the same time without exhaustive search for the...
We propose a decode-and-forward (DF) multistage cooperation protocol wherein the transmission between source and destination takes place in T ≥ 2 equal duration and orthogonal time phases with the help of relays. In the first time phase, the source broadcasts its message which is received by all potential relays. During subsequent time phases, the relays that have successfully decoded the message...
In this paper, the variational expectation-maximization (VEM) algorithm is used to provide channel estimates in a space-time decoder. The proposed estimator works for many types of space-time codes (STC), including full-rate full-diversity (FRFD) codes, Bell Laboratories layered space-time architecture (BLAST) and orthogonal STC's. The principle idea is to treat the channel coefficients as the unknown...
In this contribution, we propose a Distributed Concatenated Irregular Convolutional Coded Unity Rate Coded and Space Time Trellis Coded (DC-IrCC-URC-STTC) scheme for cooperative communications employing multiple single-antenna relays. Each coding arrangement is designed for efficient decoding convergence by employing non-binary Extrinsic Information Transfer (EXIT) charts. The source node transmits...
The exact expressions for symbol error probability and outage probability of randomized distributed space-time codes (RDSTC) under Rayleigh fading are derived. The diversity gain derived in the literature uses the Chernoff bound which may not be achievable in general. Utilizing the exact expression, the achievable diversity gain of RDSTCs is validated. The analytical expressions are verified by Monte-Carlo...
In this paper, the generation of 16-QAM and 64-QAM space-time trellis codes (STTCs) for several transmit antennas is considered. The main problem with an exhaustive search is the important time to find the best 22n-QAM STTCs, especially for great values of n and for great numbers of transmit antennas. In order to reduce this search time, an efficient method must be used to generate optimal 22n-QAM...
In this paper, a cooperative multicast scheme that uses Randomized Distributed Space Time Codes (R-DSTC), along with packet level Forward Error Correction (FEC), is studied. For the source packets, two-hop transmission is considered, where a packet is transmitted first by the access point (AP), and then forwarded using R-DSTC by the nodes that receive the packet. On the other hand, parity packets...
We demonstrate a large improvement in the tolerance of coherent polarization-multiplexed systems to polarization-dependent loss (PDL), that is achieved by use of a space-time code known as the Golden-code.
Combining coding, modulation, transmit and receive diversity, and validly increases the anti-noise performance in fading channels, OSTBC (orthogonal space-time block codes) is a new channel coding technology accompanying with the extensive application of wireless communication. Based on typical channel model of the OSTBC in MIMO (multiple-in, multiple-out) wireless communication channels, a general...
Most research on distributed space-time block coding (D-STBC) has assumed that cooperative relay nodes are perfectly synchronized, for the delay destroys the required spacetime signal structure. However, in most practical distributed scenario, perfect synchronization is hard to achieve. To deal with it, this paper applies front end prefilter (FEP) as a delay synchronization scheme which accomplishes...
We propose a data precoded relay-assisted scheme, for a system cooperating with 2 relays. We assume that all the terminals are equipped with a single antenna. The use of relays is of significant interest to allow radio access in situations where a direct path is not available. However because of the half duplex constraint at the relays, transmission of a data rate equivalent to that of a modulation...
In, the authors have proposed an analysis on the problem of space-time coding for a synchronized wireless relay networks employing AF (Amplify-and-Forward) protocol which proposes LD (linear dispersion coding) by using linear transformation. In this paper, we extend it to a asynchronous wireless networks and to reduce more processing burden on the relay nodes by allocating interleavers at each relay...
Some mobile ad hoc networks (MANETs) such as inter-vehicle communications require a transmission scheme that is robust to mobility and asynchronous reception with low setup overhead. However, many existing cooperative MANETs have complex MAC protocol and high overhead. In this paper, we propose a cross-layer design across the routing, MAC and PHY layers, called delay-tolerant cooperative diversity...
Recursive expectation-maximization (EM) algorithm along with stochastic approximation is employed in this paper to estimate unknown time-invariant/variant parameters. In addition, we modify the conventional Viterbi algorithm used in space-time encoder under the MIMO system, and give the recursive metric equation. The modified Viterbi algorithm can be used in the receiver when the MIMO channel information...
This paper proposes an OFDM based transmission scheme for asynchronous amplify-and-forward cooperative systems with two relay nodes over frequency-selective channels. To combat the inter-symbol interference from multi-path fading and timing errors, the cyclic prefix (CP) is used at both the source node and relay nodes. Unlike using IDFT and DFT modulation for two consecutive OFDM blocks respectively,...
In this paper, we investigate the cooperative communication performance involving space-time block codes (STBC), channel coding, network code and turbo decoding in a wireless Ad-hoc network scenario where two relays are employed for communications from a number of senders to a common sink. To reduce bandwidth and achieve diversity gain, STBC is applied at the two relays. Based on whether network coding...
In this paper, we propose a multi-antenna system concatenated Low-density Parity-check (LDPC) codes and Differential Space-time Block codes (DSTBC), in which channel state information (CSI) is unknown to the transmitter and the receiver. The system performance is given through computer simulation, we can see that the proposed system not only provides transmit diversity gain but also coding gain.
This paper gives the system model and the STBC encoding and decoding schemes in MIMO-OFDM system according to STBC coding theories. It focuses on researching and simulating the MIMO-OFDM system's performances, which had added STBC. We had analyzed and simulated BER performance of the system with different number of transceiver antennas. At the same time, BER performance of the system with different...
In this paper, we show how to design super-orthogonal space-time trellis codes (SOSTTCs) using the differential binary phase-shift keying (PSK) modulation for noncoherent communication systems, for which the knowledge of the channel state information (CSI) at the receiver is not necessary. Moreover, a new decoding algorithm with reduced decoding complexity is proposed. In all simulations, a geometric...
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