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This paper analyzes zero-forcing (ZF) code-aided narrow-band interference (NBI) rejection in synchronous direct-sequence code-division multiple access (DS-CDMA) systems of complex channel circumstance. The performance of decoding is badly affected based on general ZF code-aided techniques because of the phase of complex gain accounting for channel effects. The system based on modified ZF code-aided...
In this paper we evaluate the performance of a multi stage receiver for coded signals (using space time block codes) when MIMO (multi input multi output) channels are employed. This provides a new paradigm for transmission over Rayleigh fading channels where scattering phenomenon is a major obstruction. At the transmitter side data encoded using a space-time block code, and the encoded data is split...
In this paper, we proposed a joint design scheme between sphere decoding and user scheduling for multiuser MIMO uplink system. This is a cross layer design scheme which adopt the channel quality information based on user scheduling to reduced the search radius of sphere detector, it leads the better bit error ratio performance and low complexity than conventional sphere detection with fixed search...
In this paper, presented the cause of blocking artifacts and the importance of deblocking artifacts, while explained deblocking artifacts principle. Based on H.264 /AVC standard, the judgement of boundary strength (BS) is specially studied, and proposed an efficient arithmetic for deblocking filter. This efficient arithmetic can improve decoder speed and quality, and shorten about 10% of total time.
In this paper, we investigate two space-time receivers based on zero forcing (ZF) and minimum mean square error (MMSE) criteria for space-time transmit diversity (STTD) system in time varying channel. The performances of these schemes are compared with conventional Alamouti's scheme under the condition of combining with/without ordered successive interference cancellation (OSIC) in terms of normalized...
Space-time coding is widely used in wireless communication systems to provide diversity gain and channel coding is used to increase coding gain. In this paper, we investigate a new method for turbo codes which is dividing turbo encoder and decoder into several parallel coding and decoding blocks. These blocks work simultaneously and yield to much faster coding scheme in comparison with classical turbo...
In this paper, we propose a simple hardware implementation scheme of the D-STBC system. According to the theory of D-STBC, the specific implementation scheme of encoding and decoding come up. In the design, one differential encoding table is set up to replace the complex computation of the encoder; two decoding tables are set up to replace the complex computation of the decoder. Meanwhile likelihood...
Using multiple antennas in wireless communication systems proposes some degrees of freedom in system design, these degrees of freedom can be applied to improve the system reliability by using space time block coding (STBC) which provides diversity gain. Degrees of freedom also can be applied to increase the system capacity using spatial multiplexing (SM) methods. It is possible to achieve a trade-off...
An a posteriori probability (APP) detector for multiple antenna channels has presented in . It has the high advantage of providing good performance but has an NP complexity, we studied near capacity and near outage performance over multiple antenna channels thanks to optimized bit interleaved coded modulations (BICM) . We will now present a sub-optimal soft-input soft-ouput (SISO) detector based on...
Forward error correction (FEC) scheme has dual side-effects on the throughput performance for the satellite networks. One is to consume some extra bandwidth to send redundant information, and the other is to disable the corruption-aware TCP variants to differentiate the corruption events from the loss events. This may result in significant throughput jitter while satellite channel is in an unsteady...
Different from terrestrial sensor networks, underwater sensor networks use acoustic channels for communication and most sensor nodes are mobile due to water current. These distinctions feature underwater sensor networks with highly dynamic topology, high bit error rate, large propagation delay, and low available bandwidth. Traditional ARQ series are not suitable due to their frequent feedbacks, which...
The soft-output Viterbi algorithm was applied to DFH system, using the pertinence of the frequency transition. And A serial iterative structure is present, combined with an outer codec. The simulated result shows that compared with the conventional DFH demodulation algorithms, the performance improves obviously.
For the channel coding over binary erasure channel (BEC), peeling decoder (PD) is one of the most powerful and efficient decoder, especially suitable for the transmission of multimedia streams. In this paper, an improved PD scheme is proposed that can recover some or all lost information bits that a traditional PD fails. Simulation results show that the performance of the decoder is improved effectively...
This paper focuses on implementing an efficient and simplified turbo decoder with FPGA. The Max-Log-MAP algorithm is employed and a simplified and improved Max-Log- MAP algorithm is present. By carefully manipulating hardware, we implement the whole turbo decoder with a single-RSC structure. Comparing with the conventional decoder, our turbo decoder reduces about 60% hardware cost and operates up...
This paper presents a reduced-complexity soft-input soft-output detection scheme for low-density parity-check (LDPC) coded multiple-input multiple-output (MIMO) wireless communication systems employing turbo processing at the receiver. The detection algorithm is decomposed into the preprocessing and tree search stages. In preprocessing stage, we give an unbiased minimum mean-square error (MMSE) filtering...
A novel transmission scheme that mixes half-duplex decode-and-forward relay transmission (RT) with direct transmission (DT) is proposed for a MIMO relay channel. In this scheme, the source message is divided into two parts: one for DT and the other for RT. Preceding and decoding schemes are considered to convert the original relay channel into several parallel subchannels so that resource allocation...
This letter presents a soft decision-aided equalizer (SDAE), which combines linear equalizer and soft feedback interference canceller. In contrast to common turbo principle which only uses the extrinsic information from the decoder, the SDAE uses the full soft output channel decoding information and the equalizer outputs as a-prior input for the equalizer. The filter parameters of the SDAE are updated...
In this paper, we propose an efficient rate one quasi-orthogonal space-time block code for three antenna system. In order to compensate the performance degradation due to quasi-orthogonal scheme, in this proposed scheme, we incorporate a selective receiver for decoding. The receiver divides the received signals into two groups, and two receiving antennas alternatively operate to receive the divided...
We investigate the outage performance in the Nakagami fading for the decode-and-forward relaying with multiple receive antennas at the destination. A close-form expression for the outage probability is derived. Simulation results demonstrate our theoretical solution.
Parametric stereo is a state-of-the-art stereo coding method. It can efficiently encode a stereo audio signal into two parts including a monaural signal and small amount of stereo parameters. In this paper, the implementation of parametric stereo in digital radio mondial (DRM) system is presented. And the difference between parametric stereo in DRM and MPEG-4 is also discussed. Using parametric stereo,...
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