On distributions of multiple access interference for spread spectrum communication systems using M-phase spreading sequences of Markov chains

2004 ◽  
Author(s):  
H. Fujisaki
Keyword(s):  
Markov Chains ◽  
Spread Spectrum ◽  
Communication Systems ◽  
Multiple Access ◽  
Multiple Access Interference ◽  
Spread Spectrum Communication ◽  
M Phase ◽  
Spreading Sequences

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.

PERFORMANCE ANALYSIS OF MULTIPLE ACCESS CHAOTIC-SEQUENCE SPREAD-SPECTRUM COMMUNICATION SYSTEMS USING PARALLEL INTERFERENCE CANCELLATION RECEIVERS

2004 ◽  
Vol 14 (10) ◽  
pp. 3633-3646 ◽  
Author(s):  
WAI M. TAM ◽  
FRANCIS C. M. LAU ◽  
CHI K. TSE
Keyword(s):  
Spread Spectrum ◽  
Interference Cancellation ◽  
Communication Systems ◽  
Multiple Access ◽  
Minimum Mean Square Error ◽  
Chaotic Sequence ◽  
Spread Spectrum Communication ◽  
Parallel Interference Cancellation ◽  
Decorrelating Detector ◽  
Error Detector

In this Letter, we apply combined linear detector/parallel interference cancellation (PIC) detectors to jointly decode symbols in a multiple access chaotic-sequence spread-spectrum communication system. In particular, three different types of linear detectors, namely single-user detector, decorrelating detector and minimum mean-square-error detector, are used to estimate the transmitted symbols at the first stage of the PIC detector. The technique for deriving the approximate bit error rate (BER) is described and computer simulations are performed to verify the analytical BERs.

scholarly journals Suitable Spreading Sequences for Asynchronous MC-CDMA Systems

2018 ◽  
Vol 3 ◽  
pp. 9-13 ◽  
Author(s):  
Mouad Addad ◽  
Ali Djebbari
Keyword(s):  
Communication Systems ◽  
Multiple Access ◽  
Signal To Noise Ratio ◽  
Multiple Access Interference ◽  
High Data ◽  
Research Areas ◽  
Rate Transmission ◽  
Cdma Systems ◽  
Code Division Multiple ◽  
Spreading Sequences

In order to meet the demand of high data rate transmission with good quality maintained, the multi-carrier code division multiple access (MC-CDMA) technology is considered for the next generation wireless communication systems. However, their high crest factor (CF) is one of the major drawbacks of multi-carrier transmission systems. Thus, CF reduction is one of the most important research areas in MC-CDMA systems. In addition, asynchronous MC-CDMA suffers from the effect of multiple access interference (MAI), caused by all users active in the system. Degradation of the system’s bit error rate (BER) caused by MAI must be taken into consideration as well. The aim of this paper is to provide a comparative study on the enhancement of performance of an MC-CDMA system. The spreading sequences used in CDMA play an important role in CF and interference reduction. Hence, spreading sequences should be selected to simultaneously ensure low CF and low BER values. Therefore, the effect that correlation properties of sequences exert on CF values is investigated in this study. Furthermore, a numerical BER evaluation, as a function of the signal-to-noise ratio (SNR) and the number of users, is provided. The results obtained indicate that a trade-off between the two criteria is necessary to ensure good performance. It was concluded that zero correlation zone (ZCZ) sequences are the most suitable spreading sequences as far as the satisfaction of the above criteria is concerned.

Two Conversion Formulas of Known Optimal Sequences

2015 ◽  
Vol 713-715 ◽  
pp. 2012-2015
Author(s):  
Fan Xin Zeng ◽  
Zhen Yu Zhang
Keyword(s):  
Spread Spectrum ◽  
Code Division Multiple Access ◽  
Communication Systems ◽  
Multiple Access ◽  
Spread Spectrum Communication ◽  
Autocorrelation Functions ◽  
Construction Methods ◽  
Code Division Multiple

This paper investigates the construction methods of sequences with optimal autocorrelation functions. The approaches proposed by us are to convert the known optimal sequences into the required sequences. In order to arrive at our goal, we establish two conversion formulas, and summarize their performance. The proposed methods can provide lots of candidates of spread sequences for the applications of code-division multiple-access (CDMA) spread spectrum communication systems.

AN APPROACH TO CALCULATE THE BIT ERROR RATES OF MULTIPLE ACCESS CHAOTIC-SEQUENCE SPREAD-SPECTRUM COMMUNICATION SYSTEMS EMPLOYING MULTI-USER DETECTORS

2004 ◽  
Vol 14 (01) ◽  
pp. 183-206 ◽  
Author(s):  
WAI MAN TAM ◽  
FRANCIS C. M. LAU ◽  
CHI K. TSE
Keyword(s):  
Spread Spectrum ◽  
Communication System ◽  
Communication Systems ◽  
Multiple Access ◽  
Minimum Mean Square Error ◽  
Chaotic Sequence ◽  
Error Rates ◽  
Spread Spectrum Communication ◽  
Error Performance ◽  
Decorrelating Detector

In a multiple access spread-spectrum communication system, the bit error performance is usually limited by the mutual interference between users. The use of multi-user detection is an effective method to reduce such interference. In this paper, we consider two linear multi-user detectors, namely, decorrelating detector and minimum mean-square-error detector, applied to a multiple access chaotic-sequence spread-spectrum communication system. An approach to calculate the bit error rate (BER) for such systems is presented. The calculated BERs are compared with those obtained using brute-force computer simulations which give the true system performance.

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