Transmit diversity has been recently proposed to reduce the effects of fading channels in various wireless applications. Orthogonal transmit diersity (OTD) is one of the standardized techniques in 3G systems. In this ...Transmit diversity has been recently proposed to reduce the effects of fading channels in various wireless applications. Orthogonal transmit diersity (OTD) is one of the standardized techniques in 3G systems. In this paper, we apply orthogonal transmit diversity technique to multicarrier CDMA systems. Andlysis and simulation results show that performance benefits can be achieved compared with conventioal MC-CDMA systems in multipath fading channels.展开更多
On the basis of considering downlink power flux density limit, shadowing effect frequency reuse in different systems and adjoining beams of same system, adopting voice activity and polarization isolation techniques, t...On the basis of considering downlink power flux density limit, shadowing effect frequency reuse in different systems and adjoining beams of same system, adopting voice activity and polarization isolation techniques, the capacity of CDMA mobile satellite communication system at different downlink power flux density limit modes, channel spread bandwidth and mobile user’s quality factor of receiving system(G/T) are analysed and calculated, and compared with the ones of TDMA and FDMA. The conclusions are given at the end of this paper.展开更多
A new segmented correlating decoder of synchronous optical CDMA using modified prime sequence codes is proposed. The performance of the proposed system is analyzed under the assumption of Poisson shot noise model for ...A new segmented correlating decoder of synchronous optical CDMA using modified prime sequence codes is proposed. The performance of the proposed system is analyzed under the assumption of Poisson shot noise model for the receiver photodetector. The decoder technique is shown to be more effective to improve the bit error probability performance than the method using an optical hard-limiter.展开更多
A capacity calculation method of High Altitude Platform System(HAPS) is proposed in which TD-CDMA multiple access schemes are applied.With the influence of both power limit and bandwidth limit on capacity integrated,t...A capacity calculation method of High Altitude Platform System(HAPS) is proposed in which TD-CDMA multiple access schemes are applied.With the influence of both power limit and bandwidth limit on capacity integrated,the paper derives the equations by which the capacity of TD-CDMA systems can be calculated,and performs calculation on a practical system.This calculation method is quite simple and effective with a comparatively small error,which is essential to the de-signing and research on HAPS.展开更多
In this paper the impact of distinctive structure of antenna with branch correlation for an OFDM (orthogonal frequency division multiplexing)-based system, MC-CDMA (multi-carrier coded-division multiple-access) system...In this paper the impact of distinctive structure of antenna with branch correlation for an OFDM (orthogonal frequency division multiplexing)-based system, MC-CDMA (multi-carrier coded-division multiple-access) system, operating over the frequency selective fading environments is studied. For the reason of accordance with the working environments in the real world applications (urban areas) the correlated-Nakagami-m fading is adopted. Furthermore, the performance evaluation with average BER (bit error rate) formulas of MC-CDMA system with MRC (maximal ratio combining) diversity was derived with an alternative method of the complementary error function. The illustrated results are not only discussing the effect that comes from triangular, linear, and circular antenna array constructions, but the factors of branch correlation are also analyzed. Generally, it is known that the more the received branch number is, the more superior system performance of a multiple-access system will become. It is interesting to contrast to the geometric of the antenna array, that is, the little shape changing of the antenna is, the worse inferior system performance arrive at.展开更多
文摘Transmit diversity has been recently proposed to reduce the effects of fading channels in various wireless applications. Orthogonal transmit diersity (OTD) is one of the standardized techniques in 3G systems. In this paper, we apply orthogonal transmit diversity technique to multicarrier CDMA systems. Andlysis and simulation results show that performance benefits can be achieved compared with conventioal MC-CDMA systems in multipath fading channels.
文摘On the basis of considering downlink power flux density limit, shadowing effect frequency reuse in different systems and adjoining beams of same system, adopting voice activity and polarization isolation techniques, the capacity of CDMA mobile satellite communication system at different downlink power flux density limit modes, channel spread bandwidth and mobile user’s quality factor of receiving system(G/T) are analysed and calculated, and compared with the ones of TDMA and FDMA. The conclusions are given at the end of this paper.
文摘A new segmented correlating decoder of synchronous optical CDMA using modified prime sequence codes is proposed. The performance of the proposed system is analyzed under the assumption of Poisson shot noise model for the receiver photodetector. The decoder technique is shown to be more effective to improve the bit error probability performance than the method using an optical hard-limiter.
文摘A capacity calculation method of High Altitude Platform System(HAPS) is proposed in which TD-CDMA multiple access schemes are applied.With the influence of both power limit and bandwidth limit on capacity integrated,the paper derives the equations by which the capacity of TD-CDMA systems can be calculated,and performs calculation on a practical system.This calculation method is quite simple and effective with a comparatively small error,which is essential to the de-signing and research on HAPS.
文摘In this paper the impact of distinctive structure of antenna with branch correlation for an OFDM (orthogonal frequency division multiplexing)-based system, MC-CDMA (multi-carrier coded-division multiple-access) system, operating over the frequency selective fading environments is studied. For the reason of accordance with the working environments in the real world applications (urban areas) the correlated-Nakagami-m fading is adopted. Furthermore, the performance evaluation with average BER (bit error rate) formulas of MC-CDMA system with MRC (maximal ratio combining) diversity was derived with an alternative method of the complementary error function. The illustrated results are not only discussing the effect that comes from triangular, linear, and circular antenna array constructions, but the factors of branch correlation are also analyzed. Generally, it is known that the more the received branch number is, the more superior system performance of a multiple-access system will become. It is interesting to contrast to the geometric of the antenna array, that is, the little shape changing of the antenna is, the worse inferior system performance arrive at.
