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This paper proposed an efficient iterative frequency domain equalization (FDE) for cooperative multi-relay-assisted automatic repeat request (ARQ) single carrier systems operating over multiple-input-multiple-output (MIMO) channel. The receiver employs each retransmission as an additional set of virtual receive antennas to exploit the space diversity. At each iteration, soft inter-symbol interference...
The fixed-complexity sphere decoder (FSD) has been proposed to attain the near-optimal performance achieving the same diversity order as the maximum-likelihood decoder (MLD) recently. However, it suffers great redundant computations resulting in high power consumption. In this paper, we conduct an improved algorithm for the original FSD by using early termination (ET). This algorithm (abbreviated...
The fixed-complexity sphere decoder (FSD) has been proposed to attain the near-optimal performance achieving the same diversity order as the maximum-likelihood decoder (MLD). However, it suffers great redundant computations resulting in very high power consumption. In this paper, we combine the probabilistic tree pruning (PTP) method proposed recently by Shim and Kang with the original FSD. This algorithm...
Interference cancellation (IC) is an effective and easy implemented technology in the multi-user system. Previous studies demonstrate the principles of IC and IC process which show a great improvement in the system capacity with IC. However, no research has focused on the IC system's capacity domain by giving an accurate formula. This article carries on the theoretical analysis of CDMA reverse link...
A novel joint blind channel estimation and turbo equalization algorithm is proposed for orthogonal frequency-division multiplexing (OFDM) system in this paper. It has been proved that, blind channel estimation based on linear precoding can obtain channel information exactly. However, the precoding will cause inter-symbol interference (ISI). With the existence of ISI, the bit error rate (BER) performance...
The fixed-complexity sphere decoder (FSD) has been proposed to attain the near-optimal performance and achieves the same diversity order as the maximum-likelihood decoder (MLD) recently. However, its equally handling all the branches obtained via the full expansion (FE) stages till reaching the final minimum Euclidean distance (MED) decision is unnecessary. In this paper, we conduct an adaptive control...
This paper is concerned with a novel channel coding scheme called accumulate repeat tree (ART) codes which are constructed based on repeat accumulate (RA) codes and concatenated tree (CT) codes. This class of codes can be viewed as special low-density parity-check (LDPC) codes, or as special turbo codes, so they are proposed as turbo-like codes combing many advantages of LDPC and turbo codes. ART...
For orthogonal frequency-division multiplexing (OFDM) systems, the length of cyclic prefix (CP) is selected on the basis of the maximum delay spread of channel. However, the use of a CP reduces both the spectral efficiency and the power efficiency. In this paper, we proposed an iterative receiver for the space frequency block code (SFBC) OFDM system without CP. After tail cancellation, our proposed...
It is well-known that, the cyclic prefix (CP) protects orthogonal frequency-division multiplexing (OFDM) system from inter-block interference (IBI), but it also reduces the spectral efficiency. In this paper, a low-complexity turbo equalization algorithm is proposed for multiple input multiple output (MIMO) OFDM system without CP. In our algorithm, tail cancellation is performed firstly by using the...
We propose a novel iterative physical layer network and channel decoding scheme based on XOR network coding and turbo code for the multiple-access relay channel. Firstly, the system model of two access nodes and one terminal with a relay between them is presented. At the relay node physical-layer network coding (PNC) is employed to combine the data information transmitted from resource, then at the...
Compared to conventional network coding, which must combine bit streams after they are decoded, the physical layer network coding (PNC) could make full use of electromagnetic (EM) waves arrived and combine bit stream at the physical layer. Because of this the system throughput could be improved. In this scheme we integrate PNC technique into wireless video transmission based on H.264 for relay channel...
In this paper, we propose a new and practical reliability-based hybrid automatic repeat request (RB-HARQ) scheme for irregular low-density parity-check (LDPC) codes. Irregular LDPC codes have an unequal error protection (UEP) property. Using this property, we find that the middle degree message nodes of irregular LDPC codes are important for HARQ systems. If we pick out the low reliable message nodes...
For orthogonal frequency-division multiplexing (OFDM) system, the length of cyclic prefix (CP) is selected on the basis of the expected maximum delay spread. When the CP length is shorter than the maximum delay spread, inter-symbol interference (ISI) and inter-carrier interference (ICI) will occur. By means of conventional one-tap frequency domain equalization (FDE), the desired symbols can not be...
In this paper, we propose a novel receiver consists of the Inter Symbol Interference (ISI) canceller and the turbo equalizer for orthogonal frequency division multiplexing (OFDM) systems over frequency selective fading channels where the multipath delay exceeds the guard interval duration. The proposed turbo equalization algorithm performs soft Inter Carrier Interference (ICI) cancellation and frequency...
Recently, cooperative sensing which can enhance the sensing performance becomes popular in the design of cognitive radio (CR) networks. CR networks need reliable information exchange to conduct cooperative sensing, but it is difficult to transmit information for CR networks without licensed band over the air interface. In this paper, we propose to use spread spectrum technology to transmit low rate...
In this paper, we analysis the receiver of orthogonal frequency division multiplexing (OFDM) systems over frequency selective fading channels where the multipath delay exceeds the guard interval duration and propose a novel receiver scheme. The proposed receiver consists of the Inter Symbol Interference (ISI) canceller and the turbo equalizer. At each iteration, the proposed turbo equalization algorithm...
A simplified fixed-complexity sphere decoder (SFSD) with much lower computational cost than that of the original fixed-complexity sphere decoder (FSD) has been developed for signal detection in Vertical Bell Laboratories layered space-time (V-BLAST) systems. Simulation results on a 16-QAM system with 8 transmit and 8 receive antennas show that the SFSD can attain the near-optimal performance with...
In OFDMA cellular system, the inter-cell interference is main interference of the system, which greatly degrades the system performance. In the inter-cell interference mitigation scheme, interference cancellation based on IDMA is a potential technology, especially in full-loaded scenario. Although it can enhance the system performance, its well work needs many information such as MCS, which makes...
In this paper, we propose a linear minimum mean square error (MMSE)-based turbo frequency domain equalization (FDE) scheme for single carrier space-time block coded (STBC) transmissions. In the proposed iterative receiver, FDE is performed for each individual tone after space-time (ST) decoding and exchanges extrinsic information with the soft in soft out (SISO) decoder according to the turbo principle...
This paper proposes an efficient turbo frequency domain equalizer (FDE) for single carrier systems with cyclic-prefix (CP). At each iteration, the proposed algorithm performs soft inter-symbol interference (ISI) cancellation and symbol-wise minimum mean-square error (MMSE) filtering both in the frequency domain to minimize the performance degradation caused by frequency-selective channels. After the...
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