### 电子工程代写|数字信号处理代写Digital Signal Processing代考|EE615

statistics-lab™ 为您的留学生涯保驾护航 在代写数字信号处理Digital Signal Processing方面已经树立了自己的口碑, 保证靠谱, 高质且原创的统计Statistics代写服务。我们的专家在代写数字信号处理Digital Signal Processing方面经验极为丰富，各种代写数字信号处理Digital Signal Processing相关的作业也就用不着说。

• Statistical Inference 统计推断
• Statistical Computing 统计计算
• Advanced Probability Theory 高等楖率论
• Advanced Mathematical Statistics 高等数理统计学
• (Generalized) Linear Models 广义线性模型
• Statistical Machine Learning 统计机器学习
• Longitudinal Data Analysis 纵向数据分析
• Foundations of Data Science 数据科学基础

## 电子工程代写|数字信号处理代写Digital Signal Processing代考|Network Architecture of Cognitive Radio Networks

This subsection describes the network architecture and components of a CRN. Figure 1 depicts the whole network system. User devices, primary base stations, and CR base stations are the components of a basic CRN. In Fig. 1, there are two channels: channel 1 and channel 2. One primary base station operates in channel 1 and another in channel 2. Transmissions with the primary base station are done through licensed channels by mobile users, and the transmissions are called primary transmissions (denoted by solid lines). Transmissions with the CR base station can be done through either licensed or unlicensed channels and these transmissions are called secondary transmissions (marked by dotted lines). There is also another kind of trañsmission in which any usēr devicee can transmit directly to anothèr userr device.. Therefore, transmissions in a CRN can be grouped into three classes:

• Primary transmissions: Primary transmissions are most prioritized transmissions and cannot be compromised by other transmissions. These transmissions are done in a licensed channel between primary base stations and PUs. Primary transmissions are denoted by solid lines in Fig. 1.
• Secondary transmissions: Secondary transmissions are done in the absence of primary transmissions. Transmissions between the CR base station and the $\mathrm{CR}$ user are usually secondary transmissions.
• Secondary ad hoc transmissions: User-to-user communications are called ad hoc transmissions. These transmissions can continue without base stations or other components of the network architecture. Users create their own network topology and adapt any routing protocols of ad hoc networks. Users in the gray area form an ad hoc network in Fig. 1. There are a lot of routing protocols for mobile ad hoc networks. For example, the proposed routing algorithm in [1], which ensures a fair amount of communications among nodes and improves the load concentration problem, can be used in secondary ad hoc networks. The on-demand cluster-based hybrid routing protocol proposed in [2] is also applicable here.

## 电子工程代写|数字信号处理代写Digital Signal Processing代考|Spectrum Sensing

Secondary transmissions depend on spectrum sensing information, so this step should be done very accurately. Inaccurate sensing detection can lead to interferences with the PU that are highly unexpected. Though false alarms (in which channel is not occupied, but is detected as occupied) do not create interferences with the primary transmissions, it makes the CR user choose a channel from a narrower range of channels. As a result, a channel must be shared with many CR users and there would be increased competition among $\mathrm{CR}$ users to access the channel. The authors of [3] present a classification of spectrum sensing techniques. First, they classify sensing techniques into three groups: noncooperative sensing, cooperative sensing, and interference-based sensing. Noncooperative sensing is again classified into three groups: energy detection, matched filter detection, and cyclostationary feature detection. The classification is depicted in Fig. 2.

In noncooperative sensing, CR users do not share sensing information with one another. A CR user makes a decision about the PU’s presence using its own sensing information. We discuss primary transmitter detection and primary receiver detection, which are presented in $[4,5]$, in the following subsection.

Transmitter detection techniques emphasize detecting low power signals from any PU. Low power signals mix with noise from the environment and make it hard for the $\mathrm{CR}$ user to detect primary signals. A low signal-to-noise ratio, multipath fading effects, and time depression make primary transmissions detection very difficult for the CR user. We discuss some primary transmitter detection techniques including energy detection, coherent detection, and matched filter detection.

## 电子工程代写|数字信号处理代写Digital Signal Processing代考|Network Architecture of Cognitive Radio Networks

• 主传输：主传输是最优先的传输，不能被其他传输影响。这些传输是在主基站和 PU 之间的许可信道中完成的。初级传输在图 1 中用实线表示。
• 二次传播：二次传播是在没有一次传播的情况下进行的。CR基站与CR用户通常是二次传输。

## 广义线性模型代考

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## MATLAB代写

MATLAB 是一种用于技术计算的高性能语言。它将计算、可视化和编程集成在一个易于使用的环境中，其中问题和解决方案以熟悉的数学符号表示。典型用途包括：数学和计算算法开发建模、仿真和原型制作数据分析、探索和可视化科学和工程图形应用程序开发，包括图形用户界面构建MATLAB 是一个交互式系统，其基本数据元素是一个不需要维度的数组。这使您可以解决许多技术计算问题，尤其是那些具有矩阵和向量公式的问题，而只需用 C 或 Fortran 等标量非交互式语言编写程序所需的时间的一小部分。MATLAB 名称代表矩阵实验室。MATLAB 最初的编写目的是提供对由 LINPACK 和 EISPACK 项目开发的矩阵软件的轻松访问，这两个项目共同代表了矩阵计算软件的最新技术。MATLAB 经过多年的发展，得到了许多用户的投入。在大学环境中，它是数学、工程和科学入门和高级课程的标准教学工具。在工业领域，MATLAB 是高效研究、开发和分析的首选工具。MATLAB 具有一系列称为工具箱的特定于应用程序的解决方案。对于大多数 MATLAB 用户来说非常重要，工具箱允许您学习应用专业技术。工具箱是 MATLAB 函数（M 文件）的综合集合，可扩展 MATLAB 环境以解决特定类别的问题。可用工具箱的领域包括信号处理、控制系统、神经网络、模糊逻辑、小波、仿真等。