The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In a short-range multiple-input and multiple-output (SR-MIMO) transmission system that relies on line-of-sight (LOS) propagation, the channel matrix is determined by the antenna geometry, hence radio frequency (RF) signal processing by using an analog matrix circuit is a valid means of separating spatially-multiplexed multiple signal streams. To date several simple decoding methods utilizing this...
In this paper we propose a coding and decoding strategy for computing modulo M sums in a Multiple Access Channel over Additive White Gaussian Noise based on linear codes in FM. The complexity of our strategy is the same as the complexity of the linear code and we show that when there are 2 users in the network and M = 2, our strategy is close to the theoretical limit. We also provide some figures...
This paper investigates a low-density parity-check (LDPC) coded soft-decode-and-forward (SDF) relaying protocol for a two way relay channel (TWRC). In this SDF protocol, the relay evaluates the reliabilities, expressed as log-likelihood ratios (LLRs), of the received signals from the two sources. The relay then forwards a network-coded combination of the parity symbols of both sources, but in the...
In order to support high data rate communications, the third generation partnership project (3GPP) long term evolution (LTE) implements multiple-input multiple-output (MIMO) systems. In addition, to achieve excellent performance, LTE also employs turbo codes as the forward error correcting (FEC) standard. Although conventional turbo codes give satisfactory performance in the ideal MIMO, significant...
In this paper, we propose a radio-frequency (RF) energy powered cooperative transmission using RF energy harvesting which scavenges the energy from ambient radio waves. The outage probability of this system is theoretically analyzed to show the advantageous region compared with the direct transmission without RF energy harvesting relay when amplify-and-forward (AF) and decode-and-forward (DF) relaying...
Polar codes have a regular-recursive structure, which can efficiently be mapped to hardware for practical applications. A good quantization scheme plays a great important role in hardware implementation. In this paper, three uniform quantizers are designed for successive cancellation (SC) decoding of polar codes based on either optimizing the equivalent channel capacity, cutoff rate or mean-squared...
In this paper, we carry out a unified performance analysis of hybrid automatic repeat request (HARQ) with incremental redundancy (IR) from an information theoretic perspective over a point-to-point free-space optical (FSO) system. First, we introduce a novel unified expression for the distribution of a single FSO link modeled by the Gamma fading that accounts for pointing errors subject to both types...
This paper presents a structured optimization framework for reducing the computational complexity of LDPC decoders. Subject to specified performance constraints and adaptive to environment conditions, the proposed framework leverages the adjustable performance-complexity tradeoffs of the decoder to deliver satisfying performance with minimum computational complexity. More specifically, two constraint...
In this paper, we propose a novel low complexity scaling strategy of min-sum decoding algorithm for irregular LDPC codes. In the proposed method, we generalize our previously proposed simplified Variable Scaled Min-Sum (SVS-min-sum) by replacing the sub-optimal starting value and heuristic update for the scaling factor sequence by optimized values. Density evolution and Nelder-Mead optimization are...
In this paper, we employ distributed jointed source-channel (DJSC) coding based on quasi-cyclic low-density parity-check (QC-LDPC) codes in our wireless sensor network (WSN) for seismic exploration. In order to reduce the latency of jointed decoding, we propose a parallel structure of jointed decoding, and decoders of multiple sources can decode simultaneously. We make use of the soft information...
In this paper, we focus on the behavior of the Belief Propagation (BP) algorithm when decoding the Low-Density Parity-Check (LDPC) code of rate 3/4 in the DVB-S2 standard. By studying the topological structure of its Tanner graph, we raise properties inherent to the degree distribution that turns out to be strongly correlated with the decoding failures. The irregularity of the degrees seriously damages...
Polar codes are a class of codes discovered recently, which are proved to have capacity-achieving performance. The hardware implementations of successive cancellation (SC) decoding and List SC decoding are increasing dramatically now. However, throughput of these hardware structures remain to be improved on the one hand. On the other hand, stochastic computation is now wildly used because it uses...
This paper deals with MIMO detection for rank 4 3GPP Long-Term-Evolution (LTE) systems. The paper revolves around a previously known detector [1], which we shall refer to as RCSMLD (Reduced-Constellation-Size-Maximum-Likelihood-Detector). However, a direct application of the scheme in [1] to LTE/LTE-A rank 4 test cases results in unsatisfactory performance. The first contribution of the paper is to...
This paper proposes a new cooperative protocol which involves cooperation between primary and secondary users. We consider a cognitive setting with one primary user (PU) and multiple secondary users (SUs). The time resource is partitioned into discrete time slots. Each time slot, one of the SUs is scheduled for transmission according to time division multiple access scheme, and the remainder of the...
In this paper we address the problem of designing a user selection algorithm in a multiuser multiple-input multiple-output downlink scenario. Linear precoding is adopted at the transmitter and, thus, the number of users to be served at each particular scheduling period is limited by the number of available transmit and receive antennas. The adopted scheduling criterion for the user selection is based...
In this paper, we investigate the maximum throughput of a saturated rechargeable secondary user (SU) sharing the spectrum with a primary user (PU). The SU harvests energy packets (tokens) from the environment with a certain harvesting rate. All transmitters are assumed to have data buffers. In addition to its own traffic buffer, the SU has a buffer for storing the admitted primary packets for relaying;...
In this paper, we propose a dirty paper coding (DPC) scheme for the cognitive radio channel where multiple cognitive users coexist with a primary user. The cognitive transmitter is assumed to know the primary signals non-causally and is equipped with two antennas, of which each transmits to a single-antenna receiver. In our proposal, zero-forcing DPC is employed to cancel the interference not only...
In this paper, we propose a dirty paper coding (DPC) scheme that uses trellis shaping for the overlay cognitive radio channel, where a cognitive user and a primary user transmit concurrently in the same spectrum. Interference of the primary user is assumed to be known at the cognitive transmitter non-causally. Based on this knowledge, the shaping code selection, as a key feature of the proposal, is...
This paper considers the model that two mobile users communicate with a central processer (CP) via two base stations (BSs). The BSs are connected to the CP via orthogonal finite-capacity links. The theoretical capacity of this model is still an open problem. For given capacity of backhaul links, we use private message, common message and joint decoding message to explore a new achievable rate. We...
Designing an efficient MIMO decoder for higher order MIMO system such as 8×8 is a big challenge. The Group Detection (GD) method has been considered as a good choice because it balances well the trade-off between detection accuracy and computational complexity. This method converts the higher order MIMO channel matrix into several lower order matrices and then decodes these lower order matrices separately...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.