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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...
As far as a Turbo decoder is concerned, the lower Bit Err Rate (BER) at the expense of acceptable and feasible complexity, the better. In this paper, a method is proposed which employs additional redundant sequence added at the end of tail bits of an information sequence to improve performance of a Turbo decoder. Computer simulation results show that, when L=L'=1024, where L is the length of information...
This paper proposes a novel iterative decoding scheme based on stopping criterion for BICM-ID embedded turbo codes. It can yield good BER performance with lower complexity. The iterations between the components in the receiver are required to be carefully scheduled to achieve a good performance and complexity trade-off. The stopping criterion based on CE has been used for the simple scheme (CE scheme)...
Turbo codes are widely investigated due to its excellent error control ability since it was proposed and applied in the late 20 th century. But decoding algorithms for Turbo codes were complex, so there is large time delay in iteration processing course in order to obtain the excellent error control properties of turbo codes. This paper proposes an improved adaptive decoding algorithm through deeply...
In this paper, we employ to provide a method which combines Turbo codes and Low-Density Parity-Check (LDPC) codes based on Orthogonal Frequency Division Multiplexing (OFDM) system by adaptive encoding. The technique of channel estimation is used. The code rate and encoding scheme are all adaptive selection in the light of different channel conditions, so that we can make good use of these two types...
Multiple-input multiple-output (MIMO) single carrier frequency division multiple access (SC-FDMA), which combines the advantage of spatial and frequency diversities with frequency domain equalizers (FDE), has drawn great attention recently. Among all possible detection techniques, maximum-likelihood detection (MLD) is optimal, but its exponentially computational complexity precludes its use in practical...
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...
This paper investigates the design of LDPC codes over mobile DTV multipath channels. Most of the existing LDPC codes are optimized for additive white Gaussian noise (AWGN) channel, and not feasible to encounter the long burst error occurring in mobile DTV channel. Accordingly, we study the error propagation statistics of decision feedback equalizer (DFE) and formulate it into a gated noise model....
The operand-width specifications in fixed-point hardware implementations of turbo code decoders is an important design issue, since this governs the trade-off between the decoder's performance and its complexity, cost, area and energy consumption. The investigation of this issue would be extremely time-consuming in the conventional approach, which relies upon Monte-Carlo simulation based Bit Error...
In this paper, an incremental redundancy based cooperative coding scheme for wireless networks is proposed. User cooperation is an effective way of mitigating fading where one user cooperates with another user in transmitting its information, thereby providing spatial diversity. Wireless transmissions are broadcast by nature and this provides a new dimension to the system in terms of an implicit feedback...
A receiver structure based on a joint LDPC decoding and synchronization algorithm and realized on an FPGA platform is introduced. The realization system achieves the BER of 1e-5 at the channel SNR of -4.6 dB with moderate hardware complexity, and the performance degradation is less than 1.3 dB from the ideal situation. So it is suitable for deep space communications and other wireless communications.
In this paper the author focuses his study on finding the factors that decide the receiver's immunity of digital cellular mobile communication system. He starts his study from analyzing RF receiving sensitivity formula and finds that, by ways of optimizing FT (total noise factor) of the receiver's RF part and minimizing (minimum output signal to noise ratio required by communication system), the receiving...
As the degree distribution plays a key role in determining the encoding and decoding performance of fountain codes, asymptotically good degree distributions are developed in LT codes and Raptor codes. In this paper, we analyze the relationship between degree distribution and bit error rate (BER), and then we propose a method to design the output degree distribution of fountain codes by Differential...
Iterative processing in a wireless base-band receiver ensures promising error rate performance at the cost of high processing time for data retrieval. Exploration of parallelism in iterative processes, while maintaining the error rate performance, contributes toward fulfilling the high transmission rate requirements of emerging wireless communication standards. In this paper, parallelism levels available...
This paper presents the performance analysis of an improved differential frequency hopping (DFH) system under the conditions of partial-band noise jamming (PBNJ), the bit-error rate (BER) expressions are derived in terms of the characteristic functions of the decision statistics and validated by simulation results. When reducing the number of available frequency choices, the BER performance between...
Iterative decoding structure is the main feature of Turbo code decoding. It can improve the performance of Turbo decoding, but also increase the decoding complexity, time delay and power consumption. This paper proposes a parallel decoding structure of Turbo code based on double prediction control, i.e., using double prediction control module instead of two iterative decoding algorithms. Since the...
In this paper an analytical model of a MC-DS-CDMA with TF-domain spreading for wireless communication system with spatial diversity considering channel fading, Doppler shift, multi-access interference (MAI) along with AWGN channel is presented. The analysis presents a novel approach to the development of an analytical expression of signal to interference plus noise ratio (SINR) considering fading...
Most of the existing literature on wireless relaying has adopted the half-duplex (HD) protocol, where the transmission between source and destination is realized in two time frames, corresponding to source-relay and relay-destination transmission intervals, respectively. Contrarily, the full-duplex protocol offers higher capacity by letting the relay transmit and receive simultaneously in the same...
In this paper we focus on the probabilistic channel equalization in digital communications. We face the single input single output (SISO) model to show how the statistical information about the multipath channel can be exploited to further improve our estimation of the a posteriori probabilities (APP) during the equalization process. We consider not only the uncertainty due to the noise in the channel,...
Message-Passing is the main decoding algorithm for Low-Density Parity Check (LDPC) Codes, in which Logarithmic Belief Propagation (Log-BP) algorithm is the most popularly used one. Particle Swarm Optimization (PSO) can also be regarded as an optimization algorithm by message-passing, which makes it possible to combine Log-BP algorithm with PSO. PSO was introduced into Log-BP algorithm by regarding...
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