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...

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...

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...

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...

سابقه و هدف: در کشور ایران از حدود 5/88 میلیارد مترمکعب آب استحصال‌شده منابع سطحی زیرزمینی، ۸۳ یعنی 5/93 درصد به بخش کشاورزی اختصاص می‌یابد، بزرگ‌ترین مصرف‌کننده است. مصرف رو افزایش معلول جمعیت، سطح زیر کشت تولیدات هست که به‌تبع آن سبب کاهش دسترسی افت ایستابی تخلیه آبخوان‌ها شده آمارها نشان می‌دهند این استراتژیک، تهدید کمیت کیفیت است ­طوری ­که هم ­اکنون تعداد زیادی دشت­ های شرایط بحرانی قرار دا...