Use of Matched Filter in Direct Sequence Spread Spectrum Techniques

Ansari, Iffat Rehman; Uddin, Shahnawaz; Naaz, Sameena

doi:10.17485/ijst/2016/v9i47/100967

Cited by 2 publications

(1 citation statement)

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“…Then the received signal is demodulated using coherent BPSK receiver (i.e., correlation receiver) and matched filtering is followed by despreading the demodulated signal at the receiver side. Finally, the received binary message bits are detected by threshold detector and various parameters such as input SNR, output SNR, probability of error are calculated [16]. M.Raj kumar and Sri K.Raju presents the FPGA implementation of spreading code generator in direct sequence spread spectrum modulator, in this Direct Sequence Spread Spectrum where by the original data signal is multiplied with a pseudo noise spreading code to be transmitted.…”

Section: Literature Reviewmentioning

confidence: 99%

A New Scheme for Spreading & De-spreading in the Direct Sequence Spread Spectrum Mechanism

ElSharkawy¹

2022

Int. j. commun. netw. inf. secur.

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Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS) techniques are widely used to implement code-division multiple access (CDMA) in wireless communication systems. Both DSSS and FHSS systems help reducing the effects of interference on the transmitted information making it robust against channel impairments. DSSS uses a signal bandwidth that is much broader than the information signal bandwidth. Traditionally, the wide band signal is generated by multiplying the narrowband information signal with a binary code, often designated as a spreading code, to generate the wideband signal that is transmitted. The original information signal can be recreated at the receiver by multiplying the received wideband signal by the same binary code (now designated as a de-spreading code) used to generate the wideband transmitted signal. To extract the original information signal, the spreading and de-spreading codes must be in synchronism at the receiver and amplitude match with each other. A new modification for the direct sequence spread spectrum is proposed in this paper. The mechanism introduced in this approach implicates generating the wideband signal by circularly shifting the spreading code (PN) by n places, where n represents the value of the current byte of information signal. The yielded signal is modulated using BPSK modulator before transmitting it. The original information signal is extracted at the receiver by correlating the received signal (which is actually the original spread sequence circularly shifted by n places) with a locally generated replica of the spreading code. The position of the maximum value of the cross-correlation vector represents the value of the information signal byte. The proposed configuration has been implemented using Simulink simulator and the obtained results show that its performance is identical with the conventional DSSS.

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Section: Literature Reviewmentioning

confidence: 99%