scholarly journals Design of Pulse Waveform for Waveform Division Multiple Access UWB Wireless Communication System

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Zhendong Yin ◽  
Zhirui Wang ◽  
Xiaohui Liu ◽  
Zhilu Wu
Keyword(s):  
Communication System ◽  
Multiple Access ◽  
Multiple Access Interference ◽  
Wavelet Function ◽  
Correlation Property ◽  
Access Scheme ◽  
Single User ◽  
The One ◽  
Combination Mode ◽  
Correlation Properties

A new multiple access scheme, Waveform Division Multiple Access (WDMA) based on the orthogonal wavelet function, is presented. After studying the correlation properties of different categories of single wavelet functions, the one with the best correlation property will be chosen as the foundation for combined waveform. In the communication system, each user is assigned to different combined orthogonal waveform. Demonstrated by simulation, combined waveform is more suitable than single wavelet function to be a communication medium in WDMA system. Due to the excellent orthogonality, the bit error rate (BER) of multiuser with combined waveforms is so close to that of single user in a synchronous system. That is to say, the multiple access interference (MAI) is almost eliminated. Furthermore, even in an asynchronous system without multiuser detection after matched filters, the result is still pretty ideal and satisfactory by using the third combination mode that will be mentioned in the study.

A Method of Constructing Quaternary Periodic Complementary Sequence Sets for Suppression of Multiple Access Interference in CDMA Communication Systems

2014 ◽  
Vol 543-547 ◽  
pp. 2323-2328
Author(s):  
Fan Xin Zeng ◽  
Zhen Yu Zhang ◽  
Lin Jie Qian
Keyword(s):  
Communication System ◽  
Communication Systems ◽  
Multiple Access ◽  
Binary Sequence ◽  
Multiple Access Interference ◽  
New Method ◽  
Complementary Sequence ◽  
The One ◽  
Spreading Sequences

For suppressing multiple access interference (MAI) in a CDMA communication system, complementary sequence sets are employed as spreading sequences in such system. In this paper, we present a method for constructing a family of quaternary periodic complementary sequence sets, which arises from the conversion of the existing binary periodic complementary sequence sets with odd period of sub-sequences. The period of sub-sequences in the proposed sequence sets is twice as long as the one of the binary sequence sets employed, which is a drawback in the proposed method. Finally, some examples are given in order to illuminate the validity of the new method.

scholarly journals Performance analysis of spectral/spatial of OCDMA system using 2D hybrid ZCC/MD code

2019 ◽  
Vol 13 (2) ◽  
pp. 569
Author(s):  
Rima. Matem ◽  
S. A. Aljunid ◽  
M. N. Junita ◽  
C.B.M Rashidi ◽  
Israa Shihab Aqrab
Keyword(s):  
Multiple Access ◽  
Cross Correlation ◽  
Multiple Access Interference ◽  
Spectral Amplitude ◽  
Correlation Property ◽  
Two Dimensional ◽  
One Dimensional ◽  
Spectral Amplitude Coding ◽  
The One ◽  
Optical Coding

This paper proposes a new spectral/spatial code for Spectral Amplitude Coding in Optical Coding Division Multiple Access (SAC-OCDMA) called two-Dimensional hybrid ZCC/MD code. The new code combines two of the one –dimensional codes which are Zero Cross Correlation (1D ZCC) and Multi-Diagonal code (1D MD). Moreover, it produces a zero cross correlation property for each code. The main goal of this proposed code is to mitigate Phase Induced Intensity Noise and eliminate Multiple Access Interference (MAI). This proposed code can provide a better performance comparing to other codes as 2D FCC/MDW and 2D DPDC according to the obtained numerical analysis.

MULTI-USER DETECTION TO ENHANCE THE CAPACITY OF W-CDMA BASED ON THE CONJUGATE GRADIENT METHOD

2004 ◽  
Vol 13 (02) ◽  
pp. 313-323 ◽  
Author(s):  
YOSHIKAZU ARAI ◽  
KIYOMI IGARASHI ◽  
ATSUSHI FUKASAWA ◽  
YUMI TAKIZAWA
Keyword(s):  
Conjugate Gradient Method ◽  
Conjugate Gradient ◽  
Gradient Method ◽  
Matrix Equation ◽  
Multiple Access ◽  
Multiple Access Interference ◽  
Mutual Interference ◽  
Mathematical Approach ◽  
Single User ◽  
Single Radio

Multiple users communicate with individually-assigned codes on a single radio carrier frequency in a DS-CDMA system. Mutual interference among codes limits the capacity of the system. Conventional detectors of receivers are designed for a single-user neglecting the mutual interference. Multi-user detection is expected to enhance the capacity by removing the interference factors. In this paper, a new scheme is proposed corresponding to solving a huge matrix equation under multiple access interference (MAI) environments. This scheme is obtained by the mathematical approach to solve a huge matrix equation. The modeling of multi-user detection is shown, and the algorithm is given based on mathematical approach: the Conjugate Gradient Method (CGM). The characteristics of the proposed scheme are evaluated with comparison to the conventional single-user detector. The proposed scheme has been shown to be three times in capacity against single user detection with reduced complexity comparing conventional technologies based on serial and parallel configurations.

Novel Scheme for Multiple-Access Interference Mitigation with Low Complexity

2011 ◽  
Vol 143-144 ◽  
pp. 371-375
Author(s):  
Zuo Liang Yin ◽  
Hui Xiao Ma ◽  
Xing Peng Mao ◽  
Jun Cai
Keyword(s):  
Multiple Access ◽  
Interference Mitigation ◽  
Multiple Access Interference ◽  
Low Complexity ◽  
System Capacity ◽  
Error Performance ◽  
Multiuser Detector ◽  
Access Scheme ◽  
Lower Complexity

To mitigate multiple access interference and improve the system capacity, an effective multiple access scheme, called GCDMA, is proposed. Exploiting the IDMA iterative multiuser detector in each group, the intra-group interference can be effectively handled. Analysis and simulations demonstrate that the proposed technique outperforms the conventional CDMA in terms of both system capacity and bit error performance. Lower complexity of the proposed scheme can be achieved than CDMA and even IDMA.

A Review on Spectral Amplitude Coding Optical Code Division Multiple Access

2017 ◽  
Vol 38 (1) ◽  
Author(s):  
Navpreet Kaur ◽  
Rakesh Goyal ◽  
Monika Rani
Keyword(s):  
Code Division Multiple Access ◽  
Multiple Access ◽  
Noise Source ◽  
Direct Detection ◽  
Multiple Access Interference ◽  
Optical Cdma ◽  
Spectral Amplitude ◽  
Correlation Property ◽  
Spectral Amplitude Coding ◽  
Code Division Multiple

AbstractThis manuscript deals with analysis of Spectral Amplitude Coding Optical Code Division Multiple Access (SACOCDMA) system. The major noise source in optical CDMA is co-channel interference from other users known as multiple access interference (MAI). The system performance in terms of bit error rate (BER) degrades as a result of increased MAI. It is perceived that number of users and type of codes used for optical system directly decide the performance of system. MAI can be restricted by efficient designing of optical codes and implementing them with unique architecture to accommodate more number of users. Hence, it is a necessity to design a technique like spectral direct detection (SDD) technique with modified double weight code, which can provide better cardinality and good correlation property.

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