نتایج جستجو برای: cdma

تعداد نتایج: 6566  

Journal: :Journal of physics 2021

Abstract In the wireless channel environment, there are all kinds of jamming. With wide application OFDM Technology in communication system, technology signal analysis is becoming more and mature. Pure exposed no longer safe, facing risk jamming interception, especially military field. Multi-carrier Code Division Multiple Access (MC-CDMA) what combines characteristics CDMA. It has advantages sy...

H. Aghaeinia, V. Vakil,

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...

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...

Journal: :IEEE Transactions on Communications 2021

There is a growing interest in the transition from 4-step random access to 2-step machine-type communication (MTC), since well-suited short message delivery various Internet of Things (IoT) applications. In this paper, we study approach that uses code division multiple (CDMA) form channels for data packet transmissions with spreading factor less than number channels. As result, length transmiss...

Journal: :nternational journal of communication networks and information security 2022

The future wireless communication systems demand very high data rates, anti-jamming ability and multiuser support. People want large amount of to be continuously accessible in their personal devices. Direct Sequence (DS) spread spectrum based techniques such as Code Division Multiple Access (CDMA) fulfil these requirements but, at the same time, suffer from Intersymbol Interference (ISI). Multi...

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...

Chaos based communications have drawn increasing attention over the past years. Chaotic signals are derived from non-linear dynamic systems. They are aperiodic, broadband and deterministic signals that appear random in the time domain. Because of these properties, chaotic signals have been proposed to generate spreading sequences for wide-band secure communication recently. Like conventional DS...

Journal: :Applied Optics 2021

For the first time, to best of our knowledge, hybrid triple coding empowered frequency division multiple access (FDMA)-code (CDMA) mode coded optical sensor (CAOS) camera is demonstrated. Compared independent FDMA and CDMA modes, FDMA-CDMA has a novel high-security space-time-frequency signal encoding design for robust, faster, linear irradiance extraction at moderately high dynamic range (HDR)...

Journal: :Journal of Algebraic Combinatorics 2022

Abstract Alltop functions have applications to code-division multiple access (CDMA) systems and mutually unbiased bases (MUBs). construct MUBs CDMA signal sets, this motivates the continued search for further functions. The discovery of is hindered by computational complexity verification. This paper narrows space through introduction a characteristic cubic polynomial provides verification proc...

Journal: :Advances in parallel computing 2022

The spectrum used by Code Division Multiple Access (CDMA) allows for a signal with greater bandwidth spreading electromagnetic energy. Multi-Carrier CDMA (MC-CDMA) is telecommunications numerousentrée strategy that spreads each user symbol across the frequency domain distinct codes. Cognitive Radio (CR) vibrant admittance enabling technology dynamically allocating space fundamental users modify...

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