Single-input multiple-output media-based modulation (SIMO-MBM) improves the limitation of single-input multiple-output (SIMO) systems by minimizing the required number of antennas to achieve a high data rate and enhanced error performance. In this paper, we employ the quadrature dimension of the spatial constellation by decomposing the amplitude/phase modulation (APM) symbol into real and imaginary components similar to quadrature spatial modulation (QSM) to improve the overall error performance of the conventional SIMO-MBM and to achieve a higher data rate. The average bit error probability of the proposed scheme is formulated using a lower bound approach and validated by the Monte Carlo (MC) simulation results obtained. Furthermore, the effect of the suboptimal mirror activation pattern selection using channel amplitude coupled with antenna correlatio n is examined for the proposed system. The MC simulation results achieved demonstrate a substantial improvement of 3.5 dB at 10 b/s/Hz with m rf = 2 and 7 dB at 12 b/s/Hz with m rf = 4 over the conventional SIMO-MBM scheme.
In wireless Code Division Multiple Access (CDMA) system, the use of power control is indispensable to combat near-far and fading problems. Signals transmitted over a multipath propagation channel which exhibits inter-path interference and fading. The receiver has to employ measures to mitigate these effects or it will incur severe performance degradation. A classic approach in CDMA communications is the rake receiver. In this paper, the downlink performance is estimated for a CDMA mobile system at the vertex of multiple adjacent cells. At the base station the received signal is coherently dispread and demodulated using a rake receiver. The effects of power control, error correction and rake receiver were also investigated on the assumption that the received signals undergo Rayleigh fading, lognormal shadowing, and frequency selective fading. The evaluation of performance measures of base to mobile link (downlink) of a multiple-cell CDMA mobile system is presented. This study demonstrates that significant performance improvements are achievable with combined use of power control, rake receiver and error correction scheme.
Radiolocation has been previously studied for CDMA networks, the effect of Multiple Access Interference has been ignored. In this paper we investigate the problem of Radiolocation in the presence of Multiple Access Interference. An extensive simulation technique was developed, which measures the error in location estimation for different network and user configurations. We include the effects of lognormal shadow and Rayleigh fading. Results that illustrate the effects of varying shadowing losses, number of base stations involved in position location, early-late discriminator offset and cell sizes in conjunction with the varying number of users per cell on the accuracy of radiolocation estimation was presented.
In CDMA communication systems, all the subscribers share the common channel. The limitation factor on the system's capacity is not the bandwidth, but multiuser interference and the near far problem. This paper models CDMA system from the perspective of mobile radio channels corrupted by additive white noise generated by multipath and multiple access interferences. The system's receiver is assisted using different combining diversity techniques. Performance analysis of the system with these detection techniques is presented. The paper demonstrates that combining diversity techniques in the system's receivers markedly improve the performance of CDMA systems.
Three transmit antennas Uncoded Space-Time Labeling Diversity (USTLD) systems were recently proposed as a direct extension to the two transmit antennas USTLD system. By employing more antennas at the transmitter, antenna — as well as — labeling diversity (LD) can be further achieved. Existing mapper designs for three transmit antennas USTLD systems are based on symmetrical heuristics, and hence no asymmetrical mapper designs can be produced. This paper proposes a multi-function optimization genetic algorithm for the three transmit antennas USTLD system that produces mapper designs irrespective of size or symmetry. The genetic algorithm was tested on 16-, 32QAM, 16-, 32APSK and 16APSK constellations that do not exhibit diagonal symmetry. The proposed genetic algorithm had produced mapper designs that match but did not improve upon existing mapper designs for 16QAM and 32QAM, respectively. The 16APSK and 32APSK mapper designs produced achieved diversity gains of [Formula: see text] and [Formula: see text] when compared to existing third mapper designs, as well as [Formula: see text] and [Formula: see text] gain over the two transmit antennas USTLD scheme at the BER of [Formula: see text]. Furthermore, when tested on 16APSK constellations that do not exhibit diagonal symmetry, these mappers achieved diversity gains between [Formula: see text], [Formula: see text] and [Formula: see text] over the two-transmit USTLD scheme at the BER of [Formula: see text], respectively. The computational complexity of the proposed genetic algorithm was analyzed based on a previous study, which was shown to be [Formula: see text].
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