1,335 research outputs found
Exit Chart Aided Irregular Convolutional Code Design for Iterative Downlink SDMA Systems using Imperfect Channel State Information
Full text linkWe analyze a precoded and iteratively detected downlink multiuser system employing imperfect Spatio-Temporal Channel Impulse Response at the Transmitters (ST-CIRT) with the aid of Extrinsic Information Transfer (EXIT) charts. A Precoded Iterative DownLink Space Division Multiple Access (PI-DLSDMA) system proposed in our previous research is further improved and shown to be capable of maintaining an infinitesimally low BER, despite using imperfect ST-CIRT. A further novel feature of the PI-DL-SDMA system is that we design an IrRegular Convolutional Code (IRCC) with the aid of EXIT chart analysis for creating an open EXIT tunnel between the inner decoder’s and outer decoder’s EXIT curve at a reduced Eb/N0 value and hence maintain an infinitesimally low BER. Index Terms— SDMA, downlink, iterative, EXIT char
Sintering Behavior and Dielectric Properties of Yttria/Silica-Coated BaTiO3 Material with Mn-Si-O Glass
No full textReduced-Complexity Maximum-Likelihood Detection in Downlink SDMA Systems
Full text linkThe literature of up-link SDMA systems is rich, but at the time of writing there is a paucity of information on the employment of SDMA techniques in the down-link. Hence, in this paper a Space Division Multiple Access (SDMA) down-link (DL) multi-user communication system invoking a novel low-complexity Maximum Likelihood (ML) space-time detection technique is proposed, which can be regarded as an advanced extension of the Complex Sphere Decoder (CSD). We demonstrate that as opposed to the previously published variants of the CSD, the proposed technique may be employed for obtaining a high effective throughput in the so-called “over-loaded” scenario, where the number of transmit antennas exceeds that of the receive antennas. The proposed method achieves the optimum performance of the ML detector even in heavily over-loaded scenarios, while the associated computational complexity is only moderately increased. As an illustrative example, the required Eb/N0 increased from 2 dB to 9 dB, when increasing the normalized system load from unity, representing the fully loaded system, to a normalized load of 1.556
Iterative Near-Maximum-Likelihood Detection in Rank-Deficient Downlink SDMA Systems
No full textAbstract—In this paper, a precoded and iteratively detected downlink multiuser system is proposed, which is capable of operating in rankdeficient scenarios, when the number of transmitters exceeds the number of receivers. The literature of uplink space division multiple access (SDMA) systems is rich, but at the time of writing there is a paucity of information on the employment of SDMA techniques in the downlink. Hence, we propose a novel precoded downlink SDMA (DL-SDMA) multiuser communication system, which invokes a low-complexity nearmaximum-likelihood sphere decoder and is particularly suitable for the aforementioned rank-deficient scenario. Powerful iterative decoding is carried out by exchanging extrinsic information between the precoder’s decoder and the outer channel decoder. Furthermore, we demonstrate with the aid of extrinsic information transfer charts that our proposed precoded DL-SDMA system has a better convergence behavior than its nonprecoded DL-SDMA counterpart. Quantitatively, the proposed system having a normalized system load of Ls = 1.333, i.e., 1.333 times higher effective throughput facilitated by having 1.333 times more DL-SDMA transmitters than receivers, exhibits a “turbo cliff” at an Eb/N0 of 5 dB and hence results in an infinitesimally low bit error rate (BER). By contrast, at Eb/N0 = 5 dB, the equivalent system dispensing with precoding exhibits a BER in excess of 10%. Index Terms—Iterative decoding, maximum likelihood detection, space division multiple access (SDMA) downlink, sphere decoding
Signaling pathways of LIGHT induced macrophage migration and vascular smooth muscle cell proliferation.
No full textClinical characteristics of Taiwanese hereditary non-polyposis colorectal cancer kindreds
No full textHong Kong in transition: problems and prospects
Full text linkpublished_or_final_versionContributors viPreface Wesley-Smith, Peter Wesley-Smith, Peter viiThe Common Law Litton, Henry Litton, Henry 1The constitutional framework Ghai, Yash Ghai, Yash 11Constitutional interpretation Wesley-Smith, Peter Wesley-Smith, Peter 51The sources of law in the SAR Zhou, Wei Zhou, Wei 79The dilemmas of governing Lee, Jane C.Y. Lee, Jane C.Y. 9
The role of Rho-associated kinase in differential regulation by statins of interleukin-1 and lipopolysaccharide-mediated NF-B activation and inducible nitric oxide synthase gene expression in vascular smooth muscle cells.
No full textLight extraction efficiency enhancement on organic light-emitting device by microlens array attachment: a systematic approach
No full textDiagnostic Role of Endoscopy, Stool Culture, and Toxin A in Clostridium Difficile - Associated Disease
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