In non-cooperative scenarios, the spreading sequences or waveforms of direct sequence spread spectrum (DSSS) signals is unknown to receiver. This paper focuses on addressing problem blind estimation waveform under multipath channels. scenario signal path transmission, can be directly obtained based estimated waveforms. However, in presence channels, becomes convolution and channel response, thu...

The influence of microwave oven interference on IEEE802.11 Wireless Local Area Network (WLAN) performance is a significant factor because they share common spectrum in the 2.400 2.4835 GHz Industry, Science, and Medicine (ISM) band. FCC regulations permit radiated power of up to 1 watt in this band provided spread spectrum techniques are employed. Spread spectrum methods facilitate multiple use...

This work proposes a direct sequence spread spectrum transmitter with high transmission range and efficiency for audio signals. It is shown that by choosing high process gain for spread spectrum signal the data could reach a range of 55km in the 2.4GHz ISM band. By employing a light modulation scheme, we have a relaxed SNR requirement for having a low bit error rate (BER) which translates to re...

Independent Component Analysis (ICA) technique separates mixed signals blindly without any information of mixing system. The present work studies and analyses the issues involved in interference rejection in direct sequence spread spectrum communication systems based on Independent Component Analysis technique. The ICA technique tries to separate the unwanted interfering signal from the desired...

D spread spectrum (DSSS) and frequency-hopping spread spectrum (FHSS) technologies have different physical mechanisms for rejecting narrowband interference. Because of these physical differences, they perform differently in the presence of the same levels of narrowband interference. This is an important case for successful operation in the ISM bands. After presenting the physical mechanisms by ...

This work concentrates on the problem of watermarking embedding and optimum detection in color images through the use of spread spectrum techniques, both in space (Direct Sequence Spread Spectrum or DSSS) and frequency (Frequency Hopping). It is applied to RGB and opponent color component representations. Perceptive information is considered in both color systems. Some tests are performed in or...

This paper presents a method of embedding information in digital images and video, which helps to trace illegal copies. This method of watermarking uses the principle of direct sequence spread spectrum. Spread spectrum signals are particularly resistant to non-linear amplitude distortion and additive noise, but are not resistant to timing errors. Using a sliding correlator, it is possible to de...

This work concentrutes on the problem of wutermurking embedding und optimum detection in color imuges through the use of spread spectrum techniques, both in spuce (Direct Sequence Spread Spectrum or DSSS) and fiequency (Frequency Hopping). It is applied to RGB und opponent color component representutions. Perceptive information is considered in both color systems. Some tests are performed in or...

Ultra-wideband radio systems operate using extremely short duration signaling pulses. Spread spectrum techniques for multiple access and interference suppression are commonly considered for such systems. We compare time-hopping spread spectrum with pulse position modulation (TH-PPM) and timehopping/direct-sequence spreading with antipodal signaling (TH/DS-BPSK) in terms of their multiple access...

Wireless networking is rapidly growing and becomes an inexpensive technology which allows multiple users to simultaneously access the network and the internet while roaming about the campus. In the present work , the software development of a wireless LAN(WLAN) is highlighted. This WLAN utilizes direct sequence spread spectrum (DSSS) technology at 902MHz RF carrier frequency in its physical lay...