Bit Loading Algorithm of VSF-OFCDM Wireless Communication

2014 ◽  
Vol 539 ◽  
pp. 211-219
Author(s):  
Mao Tong Xu
Keyword(s):  
Wireless Communication ◽  
Wide Band ◽  
Wireless Channel ◽  
Total Power ◽  
Subcarrier Allocation ◽  
Frequency Space ◽  
Bit Loading ◽  
Power Limit ◽  
And Performance ◽  
System Frequency

In VSF-OFCDM wireless communication, wireless channel is divided into component channels with the same frequency space according to the frequency, and the carriers on component channels are mutually orthogonal. When there are enough subcarriers, the bandwidth efficiency of the system is close to nyquist limit, which can ensure the utilization ratio of system frequency. Therefore, under the premise of ensuring orthogonal division of channels, the channels received a secondary division according to data rate requirements and power limit of business to make the frequency resource fully used and makes the total power minimal, which realizes the optimal distribution of wireless-communication system resources. The secondary division is represented by bit loading algorithmthe best bit number of subcarrier allocation in symbol period. For the characteristics of wide-band multi-media services and granular division of VSF-OFCDM wireless communication, the subject proposes the idea of business-oriented subcarrier allocation, which means that the subcarriers are divided in symbol period with the business as the dominant. Based on the idea, the paper designs service-oriented bit loading algorithm of subcarrier, byte and power combined with distribution based on channel detection, and makes verification and performance analysis on the algorithm.

Subcarrier Allocation in Cognitive Radio Systems

2012 ◽  
Vol 195-196 ◽  
pp. 154-158
Author(s):  
Pei Zhang ◽  
Long Xiang Yang ◽  
Xu Liu
Keyword(s):  
Resource Allocation ◽  
Cognitive Radio ◽  
Numerical Results ◽  
Total Power ◽  
Subcarrier Allocation ◽  
Allocation Algorithm ◽  
Cognitive Radio Systems ◽  
Radio Systems ◽  
And Performance ◽  
Cr System

In CR systems, resource allocation is very important, which can be operated by different rules, according to the different purposes. In this paper, we focus on subcarrier allocation in CR systems, where primary and CR users co-exist in adjacent bands, while keeping the total interference introduced to the PU band below a certain threshold and the total power allocated to the CR users under a constraint. First, we investigate Max-Rate subcarrier allocation algorithm (MaxR-SAA) which can achieve maximum transmit rate of the CR system. Then, focusing on the fact that the less interference introduced to the PU band, the better the PU can work; we proposed a Min-Interference subcarrier allocation algorithm (MinI-SAA). Further, aiming at achieving fairness among all the SUs, we propose a subcarrier allocation algorithm, which is termed as Fair-Rate subcarrier allocation algorithm (FairR-SAA). Numerical results are obtained for the behaviors and performance of our proposed algorithms.

Introduction to Wireless Endogenous Security and Safety: Problems, Attributes, Structures and Functions

2021 ◽  
Author(s):  
Xiaoyan Hu ◽  
Liang Jin ◽  
Yangming Lou ◽  
Zhou Zhong ◽  
Xiaoli Sun
Keyword(s):  
Wireless Communication ◽  
Communication System ◽  
Communication Systems ◽  
Wireless Channel ◽  
Communication Security ◽  
Wireless Communication Systems ◽  
Functional Safety ◽  
Wireless Communication System ◽  
Safety Technology ◽  
Safety Attributes

Abstract: The information security and functional safety of wireless communication systems have become the focus of current research. The endogenous security principle based on Dynamic Heterogeneous Redundancy provides a direction for the development of wireless communication security and safety technology. This paper introduces the concept of wireless endogenous security from the following four aspects. First, we sorts out the endogenous security problems faced by the current wireless communication system, and then analyzes the endogenous security and safety attributes of the wireless channel. After that, the endogenous security and safety structure of the wireless communication system is given, and finally the applications of the existing wireless communication endogenous security and safety functions are listed. <br>

Design of Logistic Map-Based Spreading Sequence Generation for Use in Wireless Communication

2015 ◽  
pp. 81-121 ◽  
Author(s):  
Katyayani Kashayp ◽  
Kandarpa Kumar Sarma ◽  
Manash Pratim Sarma
Keyword(s):  
Wireless Communication ◽  
Spread Spectrum ◽  
Logistic Map ◽  
Chaotic Sequence ◽  
Wireless Channel ◽  
Computational Time ◽  
Spreading Sequence ◽  
Sequence Generation ◽  
Critical Issues ◽  
Code Division Multiple

Spread spectrum modulation (SSM) finds important place in wireless communication primarily due to its application in Code Division Multiple Access (CDMA) and its effectiveness in channels fill with noise like signals. One of the critical issues in such modulation is the generation of spreading sequence. This chapter presents a design of chaotic spreading sequence for application in a Direct Sequence Spread Spectrum (DS SS) system configured for a faded wireless channel. Enhancing the security of data transmission is a prime issue which can better be addressed with a chaotic sequence. Generation and application of chaotic sequence is done and a comparison with Gold sequence is presented which clearly indicates achieving better performance with simplicity of design. Again a multiplierless logistic map sequence is generated for lower power requirements than the existing one. The primary blocks of the system are implemented using Verilog and the performances noted. Experimental results show that the proposed system is an efficient sequence generator suitable for wideband systems demonstrating lower BER levels, computational time and power requirements compared to traditional LFSR based approaches.

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