宽带电力线载波通信采用自适应正交频分复用(orthogonal frequency division multiplexing,OFDM)技术有效提升了通信速率,为实现电力多业务应用提供了丰富的通信资源保证。现有研究多是基于单一层级的网络状态进行资源划分,各业务所需...宽带电力线载波通信采用自适应正交频分复用(orthogonal frequency division multiplexing,OFDM)技术有效提升了通信速率,为实现电力多业务应用提供了丰富的通信资源保证。现有研究多是基于单一层级的网络状态进行资源划分,各业务所需速率多为静态预先设定且为固定值,因此会导致各子载波信噪比存在明显差异性的情况下,系统无法根据业务的不同QoS需求及网络中实时队列长度对所需资源进行自适应调整。抑或缺乏依据当前网络状态的动态调配灵活性,导致通信资源的浪费或通信需求无法满足。文章针对并发多业务的资源分配问题,通过应用层、数据链路层、物理层间的数据映射,建立了跨层资源分配模型。根据应用层电力多业务的QoS需求、数据链路层缓存区内队列长度以及底层物理层子载波和系统功率,将数据分组等待时延以及分组损耗映射为实时/非实时类用户的最低传输速率,进而提出基于效用函数的MAC层用户调度和物理层资源分配算法。最后通过典型电力线信道环境仿真实验发现:所提算法比现有2个电力线载波资源分配算法在多业务并发场景下单用户的吞吐量最高可提升47.62%,分组等待时延缩短37.25%,分组损耗降低72.04%。更好的资源分配使得文章所提算法能够在保证QoS需求情况下,允许更多的用户同时接入系统,有效提升了基于OFDM的宽带电力线载波通信资源利用率。展开更多
The likelihood function plays a central role in statistical analysis in relation to information, from both frequentist and Bayesian perspectives. In large samples several new properties of the likelihood in relation t...The likelihood function plays a central role in statistical analysis in relation to information, from both frequentist and Bayesian perspectives. In large samples several new properties of the likelihood in relation to information are developed here. The Arrow-Pratt absolute risk aversion measure is shown to be related to the Cramer-Rao Information bound. The derivative of the log-likelihood function is seen to provide a measure of information related stability for the Bayesian posterior density. As well, information similar prior densities can be defined reflecting the central role of likelihood in the Bayes learning paradigm.展开更多
文摘宽带电力线载波通信采用自适应正交频分复用(orthogonal frequency division multiplexing,OFDM)技术有效提升了通信速率,为实现电力多业务应用提供了丰富的通信资源保证。现有研究多是基于单一层级的网络状态进行资源划分,各业务所需速率多为静态预先设定且为固定值,因此会导致各子载波信噪比存在明显差异性的情况下,系统无法根据业务的不同QoS需求及网络中实时队列长度对所需资源进行自适应调整。抑或缺乏依据当前网络状态的动态调配灵活性,导致通信资源的浪费或通信需求无法满足。文章针对并发多业务的资源分配问题,通过应用层、数据链路层、物理层间的数据映射,建立了跨层资源分配模型。根据应用层电力多业务的QoS需求、数据链路层缓存区内队列长度以及底层物理层子载波和系统功率,将数据分组等待时延以及分组损耗映射为实时/非实时类用户的最低传输速率,进而提出基于效用函数的MAC层用户调度和物理层资源分配算法。最后通过典型电力线信道环境仿真实验发现:所提算法比现有2个电力线载波资源分配算法在多业务并发场景下单用户的吞吐量最高可提升47.62%,分组等待时延缩短37.25%,分组损耗降低72.04%。更好的资源分配使得文章所提算法能够在保证QoS需求情况下,允许更多的用户同时接入系统,有效提升了基于OFDM的宽带电力线载波通信资源利用率。
文摘The likelihood function plays a central role in statistical analysis in relation to information, from both frequentist and Bayesian perspectives. In large samples several new properties of the likelihood in relation to information are developed here. The Arrow-Pratt absolute risk aversion measure is shown to be related to the Cramer-Rao Information bound. The derivative of the log-likelihood function is seen to provide a measure of information related stability for the Bayesian posterior density. As well, information similar prior densities can be defined reflecting the central role of likelihood in the Bayes learning paradigm.
