自网络诞生以来,认证(au then tication)、授权(au thorization)和计费(accoun ting)体制(AAA)成为其运营的基础。网络中各类资源的使用,都由认证,授权,计费来管理。随着网络规模的扩大,传统的认证方式已不能适应用户数量的急增和宽带...自网络诞生以来,认证(au then tication)、授权(au thorization)和计费(accoun ting)体制(AAA)成为其运营的基础。网络中各类资源的使用,都由认证,授权,计费来管理。随着网络规模的扩大,传统的认证方式已不能适应用户数量的急增和宽带业务多样化的要求,需要采用新方法对用户的接入进行控制和配置。因此,针对不同的网络环境,提出了不同的网络用户接入认证技术。通过分析和比较,阐明了各种高速网络用户接入认证技术的特点。展开更多
Two adaptive power and bit loading algorithms to maximize the throughput of MIMO-OFDM systems in frequency selective fading environment are proposed. The two algorithms allocate bit based on maximizing the overall thr...Two adaptive power and bit loading algorithms to maximize the throughput of MIMO-OFDM systems in frequency selective fading environment are proposed. The two algorithms allocate bit based on maximizing the overall throughput. One algorithm allocates power based on guaranteeing that the bit error rate (BER) of each sub-carrier and the total allocated power remain below a target BER threshold and a power threshold, respectively; another one allocates power based on guaranteeing that the mean BER of sub-carriers and the total allocated power remain below a target BER threshold and a power threshold, respectively. The simulation results show that the proposed algorithms can achieve faster throughput with lower computational complexity, which indicates that the proposed algorithms are effective when compared to some existing algorithms.展开更多
文摘自网络诞生以来,认证(au then tication)、授权(au thorization)和计费(accoun ting)体制(AAA)成为其运营的基础。网络中各类资源的使用,都由认证,授权,计费来管理。随着网络规模的扩大,传统的认证方式已不能适应用户数量的急增和宽带业务多样化的要求,需要采用新方法对用户的接入进行控制和配置。因此,针对不同的网络环境,提出了不同的网络用户接入认证技术。通过分析和比较,阐明了各种高速网络用户接入认证技术的特点。
基金the National Natural Science Foundation of China (60496313).
文摘Two adaptive power and bit loading algorithms to maximize the throughput of MIMO-OFDM systems in frequency selective fading environment are proposed. The two algorithms allocate bit based on maximizing the overall throughput. One algorithm allocates power based on guaranteeing that the bit error rate (BER) of each sub-carrier and the total allocated power remain below a target BER threshold and a power threshold, respectively; another one allocates power based on guaranteeing that the mean BER of sub-carriers and the total allocated power remain below a target BER threshold and a power threshold, respectively. The simulation results show that the proposed algorithms can achieve faster throughput with lower computational complexity, which indicates that the proposed algorithms are effective when compared to some existing algorithms.
