Although the Cramer-Rao Bound(CRB) can be used as the benchmark of estimation algorithm performance,it's too complicated for joint training sequence(TS) design for multiple input multiple output(MIMO) orthogonal f...Although the Cramer-Rao Bound(CRB) can be used as the benchmark of estimation algorithm performance,it's too complicated for joint training sequence(TS) design for multiple input multiple output(MIMO) orthogonal frequency division multiplexing(OFDM) coordination on multiple point(CoMP) systems.So a minimum mean square error(MSE) based sub-optimal sequence design criterion was proposed,including ideal sequence correlation property and sequence length constraint.The simulation results verify the theory analysis.展开更多
In ultra-dense networks （UDN）, the local precoding scheme for time-division duplex coordinated multiple point transmission （TDD-CoMP） can have a good performance with no feedback by using reciprocity between uplin...In ultra-dense networks （UDN）, the local precoding scheme for time-division duplex coordinated multiple point transmission （TDD-CoMP） can have a good performance with no feedback by using reciprocity between uplink and dovallink. However, if channel is time-varying, the channel difference would cause codeword mismatch between transmitter and receiver, which leads to performance degradation. In this paper, a linear interpolation method is proposed for TDD-CoMP system to estimate the uplink channel at the receiver, which would reduce the channel difference caused by time delay and decrease the probability of codeword mismatch between both sides. Moreover, to mitigate severe inter-cell interference and increase the coverage and throughput of celledge users in UDN, a two-codebook scheme is used to strengthen cooperation between base stations （BSs）, which can outperform the global precoding scheme with less overhead. Simulations show that the proposed scheme can significantly improve the link performance compared to the global precoding scheme.展开更多
为了提高椭圆曲线标量乘法的效率,根据将求逆转换为乘法运算的思想,提出了在二进制域F2n上用仿射坐标直接计算7P的两种算法。两种算法分别通过引入公因子和除法多项式来计算7P,其运算量分别为2I+7S+14M和I+6S+20M,比Purohit等提出的算法...为了提高椭圆曲线标量乘法的效率,根据将求逆转换为乘法运算的思想,提出了在二进制域F2n上用仿射坐标直接计算7P的两种算法。两种算法分别通过引入公因子和除法多项式来计算7P,其运算量分别为2I+7S+14M和I+6S+20M,比Purohit等提出的算法(PUROHIT G N,RAWAT S A,KUMAR M.Elliptic curve point multiplication using MBNR and Point halving.International Journal of Advanced Networking and Applications,2012,3(5):1329-1337)分别节省了一次和两次求逆运算。同时还给出直接计算7kP的快速算法,该算法比重复计算k次7P更有效。最后结合半点运算和扩展多基表示形式将这些新算法应用到标量乘法中。实验结果表明,在美国国家标准技术研究所(NIST)推荐的椭圆曲线上,当预存储点的个数为2和5时,新算法比Purohit算法效率提高了30%和37%,比洪银芳等所提的算法(洪银芳,桂丰,丁勇.基于半点和多基表示的标量乘法扩展算法.计算机工程,2011,37(4):163-165)效率提高了9%和13%。新算法以增加少量的预计算存储为代价,能有效降低标量乘法的运算量。展开更多
基金International Science&Technology Cooperation Projects of Qinghai,China(Nos.2013-H-811,2014-HZ-821)Chunhui Plan Projects,China(Nos.Z2014013,Z2014014)
文摘Although the Cramer-Rao Bound(CRB) can be used as the benchmark of estimation algorithm performance,it's too complicated for joint training sequence(TS) design for multiple input multiple output(MIMO) orthogonal frequency division multiplexing(OFDM) coordination on multiple point(CoMP) systems.So a minimum mean square error(MSE) based sub-optimal sequence design criterion was proposed,including ideal sequence correlation property and sequence length constraint.The simulation results verify the theory analysis.
文摘In ultra-dense networks （UDN）, the local precoding scheme for time-division duplex coordinated multiple point transmission （TDD-CoMP） can have a good performance with no feedback by using reciprocity between uplink and dovallink. However, if channel is time-varying, the channel difference would cause codeword mismatch between transmitter and receiver, which leads to performance degradation. In this paper, a linear interpolation method is proposed for TDD-CoMP system to estimate the uplink channel at the receiver, which would reduce the channel difference caused by time delay and decrease the probability of codeword mismatch between both sides. Moreover, to mitigate severe inter-cell interference and increase the coverage and throughput of celledge users in UDN, a two-codebook scheme is used to strengthen cooperation between base stations （BSs）, which can outperform the global precoding scheme with less overhead. Simulations show that the proposed scheme can significantly improve the link performance compared to the global precoding scheme.
文摘为了提高椭圆曲线标量乘法的效率,根据将求逆转换为乘法运算的思想,提出了在二进制域F2n上用仿射坐标直接计算7P的两种算法。两种算法分别通过引入公因子和除法多项式来计算7P,其运算量分别为2I+7S+14M和I+6S+20M,比Purohit等提出的算法(PUROHIT G N,RAWAT S A,KUMAR M.Elliptic curve point multiplication using MBNR and Point halving.International Journal of Advanced Networking and Applications,2012,3(5):1329-1337)分别节省了一次和两次求逆运算。同时还给出直接计算7kP的快速算法,该算法比重复计算k次7P更有效。最后结合半点运算和扩展多基表示形式将这些新算法应用到标量乘法中。实验结果表明,在美国国家标准技术研究所(NIST)推荐的椭圆曲线上,当预存储点的个数为2和5时,新算法比Purohit算法效率提高了30%和37%,比洪银芳等所提的算法(洪银芳,桂丰,丁勇.基于半点和多基表示的标量乘法扩展算法.计算机工程,2011,37(4):163-165)效率提高了9%和13%。新算法以增加少量的预计算存储为代价,能有效降低标量乘法的运算量。
