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We propose a new framework for MIMO decoding based on a recently developed technique for reliably conveying linear equations over wireless channels. Each transmit antenna sends an independent data stream using the same linear code. As a result, any integer combination of the codewords is itself a codeword. Each receive antenna observes a random complex-valued combination of the codewords according...
In this paper, we evaluate a multilevel coding (MLC) scheme with multi-stage decoding (MSD) designed for satellite broadcasting communications, where services with different quality of service (QoS) are desirable. A simple Land-Mobile-Satellite (LMS) channel model is presented, based on channel states and their transitions. The instantaneous channel capacity for suburban and forest scenarios is calculated...
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...
Cooperative communication has been recently proposed as a way to improve the performance of wireless communication. However, due to the half duplex constraint, most of the relay networks face a fundamental challenge in terms of multiplexing loss. In this paper, we present an adaptive cooperation via relay selection (ACRS) protocol that improves spectral efficiency. This protocol lets the source transmit...
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...
We propose a cooperative transmission scheme for two users with one common relay using superposition modulation. It uses distributed Turbo codes (DTCs) for each user. The relay always decodes, then interleaves and re-encodes the decoded data. A new packet is formed by combining the re-encoded packets from both users using superposition modulation. This packet is forwarded to the destination with the...
In this paper we present an architectural analysis of a smart DMA (sDMA) controller for protocol stack acceleration in mobile devices supporting 3GPP's Long Term Evolution (LTE). This concept already demonstrated a significant performance benefit over conventional approaches by on-the-fly header decoding and deciphering for the data plane of the LTE protocol stack layer 2 in downlink direction. With...
In this paper, we consider the effect of different rules of symbol decision on the performance of decision-directed synchronizers for LDPC-coded systems. Different from the conventional hard symbol decision based on the Maximum-A- Posteriori (MAP) criterion, soft symbol decision can be considered as the Minimum-Mean-Square-Error (MMSE) estimation of the transmitted symbol. By whether or not the coding...
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...
This paper proposes a novel partial decode-and-forward (DF) relaying strategy with multiple antennas. In the first phase, the source broadcasts data streams consisting of non-forwarding and forwarding data streams. In the second phase, a relay node forwards only forwarding data streams to a destination node, and a destination node decodes both non-forwarding and forwarding data streams by successive...
Multicell joint processing has been shown to efficiently suppress inter-cell interference, while providing a high capacity gain due to spatial multiplexing across distributed Base Stations (BSs). However, the complexity of the optimal joint decoder in the multicell uplink channel grows exponentially with the number of users, making it prohibitive to implement in practice. In this direction, this paper...
This paper presents a novel joint network and channel decoding-interference canceling (JNCD-IC) algorithm for HARQ in wireless broadcasting system. In this system, the base station uses network coding for retransmission. In the retransmission phase, JNCD-IC scheme is proposed for the receivers to recover multiple error packets from the composite packet which is formed by XORing error packets from...
There are few analytical formulas that can be used for calculating the block error rate (BLER) in block fading channels. Thus, an estimate of the BLER is often obtained using numerical methods. One such method is the threshold method which assigns 0 or 1 to the instantaneous BLER given the signal to noise ratio (SNR) level. It has been shown that utilizing such a method results in an accurate approximation...
Systematic Luby Transform (SLT) codes constitute rateless codes, which are capable of adaptively adjusting their code rate depending on the channel quality without explicit channel state information (CSI) at the transmitters. SLTs are also suitable for space-time collaboration aided relay networks. In this paper, an iterative decoding aided SLT scheme is combined with 16-QAM transmission in a wireless...
In this paper, a joint channel-network coding is proposed for the multiple access half duplex relay channel. To improve performance, the classical constraints of orthogonality between links are partially relaxed, i.e., in the first transmission phase the two sources are allowed to transmit simultaneously, while in the second phase, the relay transmits alone and the sources are silent. In order to...
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 compress-and-forward relay scheme developed by (Cover and El Gamal, 1979) is modified by realizing that it is not necessary for the destination to decode the compressed observation of the relay; and even if the compressed observation is to be decoded, it can be more easily done by joint decoding with the original message, rather than in a successive way. This modification introduces flexibility...
In this paper, we propose Low-density Parity-check (LDPC) codes for two-way relay channels, where two sources communicate with each other through a relay. At the relay, a simpler interference cancellation joint decoder decodes for the multiple access phase of two-way relay channels. Then, the relay codeword is encoded from two decoded source codewords with LDPC codes. At source, a sub-optimal belief...
To overcome the problem that the transmission rate of a multicast channel is limited by the user with the worst channel quality, which causes the total system throughput to be low, the use of both multicast and unicast channels for multicast service is considered in this paper. Unicast channels, in addition to a multicast channel, are allocated to users with signal-to-noise ratios (SNRs) lower than...
Interference cancelation (IC) has been well studied in literature as a potential capacity approaching scheme for uplink code-division multiple-access (CDMA) systems. With the advance of silicon technology, it is becoming implementationally feasible. In this paper, we study a soft IC algorithm which could be iteratively concatenated with Turbo decoding. The algorithm only relies on a conventional single...
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