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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...
Streaming media network transmission has specific QoS problems such as high package loss ratio, low throughput caused by bit error rate (BER) and transmission delay. A brand new framework based on EMIPLIB (DM media over IP library) is lodged in this article hereinafter by systemic analysis on the QoS index of streaming media. This framework, mentioned hereinbefore, preferably presents a designing...
In this paper, we propose an extension of two dimensions (2D) code cardinality for slightly same performance (BER). The code is developed for optical code division multiple access (OCDMA) system, it is generated by: hyperbolic code for the Time Spreading and merged M-sequences for the Frequency-Hopping. In this work, we consider the Optical Fast Frequency Hopping technique OFFH-CDMA as an access technique...
This paper applies the sigma mapping of M-QAM in linear diversity-embedded space-time block codes (LDE-STBC) to achieve different diversity levels and various coding gains for unequal error protection (UEP). By controlling the basis vectors of sigma mapping, the bit error rate (BER) performance of each bit in a layer can be made to satisfy its quality-of-service (QoS) requirement. Moreover, with the...
In mobile radio systems, transmission conditions actually encounter large variations depending on the effective environmental configurations. Training sequences are periodically inserted into the transmitted messages so that the receiver can estimate the channel response. Based on this knowledge, we study the problem of adapting the equalizer filter length to a given channel impulse response under...
Provision of guaranteed quality of service (QoS) in wireless communication has always been a demanding task. QoS can be ensured by the mechanism of repeat request, however real time systems can tolerate only a finite delay. In this paper we investigate the problem of provision of guaranteed QoS by hybrid automatic repeat request (HARQ) schemes, based on soft outputs of a channel decoder. Focus is...
We consider the decoding of bit interleaved coded modulation (BICM) applied to multiband OFDM for practical scenarios where only a noisy (possibly very bad) estimate of the channel is available at the receiver. First, a decoding metric based on the channel a posteriori probability density, conditioned on the channel estimate is derived and used for decoding BICM multiband OFDM. Then, we characterize...
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