CDMA – Code Division Multiple Access
نویسنده
چکیده
Code Division Multiple Access (CDMA) is probably the most interesting multiple access method provided by spread spectrum technology. CDMA refers to a multiple access method in which the individual terminals use spreadspectrum techniques and occupy the entire spectrum whenever they transmit. This paper focuses on direct-sequence spread-spectrum principles (processing gain, spreading, de-spreading, modulation and codes) and more into CDMA cellular system fundamentals like multiple access interference (MAI), multipaths, RAKE receiver, power control and soft handover. Also the capacity of a CDMA system is discussed. Also CDMA applications in cellular system standards such as IS-95, CDMA2000 and Wideband CDMA are briefly introduced.
منابع مشابه
A Novel Multi-user Detection Approach on Fluctuations of Autocorrelation Estimators in Non-Cooperative Communication
Recently, blind multi-user detection has become an important topic in code division multiple access (CDMA) systems. Direct-Sequence Spread Spectrum (DSSS) signals are well-known due to their low probability of detection, and secure communication. In this article, the problem of blind multi-user detection is studied in variable processing gain direct-sequence code division multiple access (VPG D...
متن کاملBit Error Performance for Asynchronous Ds Cdma Systems Over Multipath Rayleigh Fading Channels (RESEARCH NOTE)
In recent years, there has been considerable interest in the use of CDMA in mobile communications. Bit error rate is one of the most important parameters in the evaluation of CDMA systems. In this paper, we develop a technique to find an accurate approximation to the probability of bit error for asynchronous direct–sequence code division multiple–access (DS/CDMA) systems by modeling the multipl...
متن کاملReducing the Limitation on Application of Synchronous Decorrelating Detector Cdma Systems
In CDMA (Code - Division Multiple - Access) systems multi - user accessing of a channel is possible. Under the assumptions of Optimum multi - user and decorrelating detector in CDMA systems. By using signals with zero and / or identical cross correlations, a simple and expandable decorrelating detector with optimum efficiency which can be easily implemented are proposed. Constructing these sign...
متن کاملThroughput Improvement of STS-Based MC DS-CDMA System with Variable Spreading Factor
The throughput enhancement of Space-Time Spreading (STS)-based Multicarrier Direct Sequence Code Division Multiple Access (MC DS-CDMA) system is investigated in this paper. Variable Spreading Factor (VSF) is utilized to improve the data throughput of the system. In this contribution, an analytical approach is proposed to compute a new expression for the Bit Error Rate (BER) performance of t...
متن کاملCapacity Improvement with DFC in QAM-CDMA
The use of Code Division for Multiple Access or CDMA is well established. We know that it has advantages in multipath environment and increase in capacity due to sectoring antenna and voice activity factor. Here a step by step comparison is made among Frequency Division Multiple Access, Time Division Multiple Access and Code Division Multiple Access when capacity or SNR is of main concern. A de...
متن کاملPerformance Analysis of TD-CDMA System
In wireless communication system Code Division Multiple Access (CDMA) is the most popular and secures technology in Multiuser Detection (MUD. To get the better performance of system the combination of TDMA and CDMA that is Time Division Code Division Multiple Access (TD-CDMA) is used in the communication system. In this paper, different users with spreading walsh code have been used to compute ...
متن کامل