Title :
Performance of DS/SFH-SSMA system with overlapping BFSK in the presence of both MTJ and MAI
Author :
Ryu, Heung-Gyoon ; Park, Jeong-Min ; Kim, Kie-Keun ; Choi, Young-Kyun
Author_Institution :
Dept. of Electr. & Electron. Eng., Chungbuk Nat. Univ., Cheongju, South Korea
fDate :
1/1/2003 12:00:00 AM
Abstract :
The performance of a direct-sequence (DS)/SFH-SSMA communication system using overlapping binary frequency-shift keying (BFSK) modulation is analyzed in additive white Gaussian noise (AWGN), multiple-access interference (MAI), and multitone jamming (MTJ) channels. An SSMA system is considered where the DS spread spectra are overlapped and the maximum overlapping limitation is 1/T, which is the minimum spacing for noncoherent FSK signaling. As the amount of overlapping increases, the multiple-access interference as well as the processing gain becomes larger. Thus, the bit error rate (BER) can be improved by optimizing the overlap ratio. The phase angles and time delays of the received signals, and the phase angles of tone jamming signals, are assumed to be mutually independent random variables. A BER equation is derived for the overlapping BFSK DS/SFH-SSMA communication system in the AWGN, MAI, and MTJ channels. From the numerical analyses and the simulation results, the BER performance is improved by about 3 dB at a BER of 10-3 in the optimized overlapping system over the nonoverlapping system under the condition that the total processing gain is 39 dB, the number of total user is 100, jammer-to-signal ratio is 20 dB, and the number of jamming tones is ten.
Keywords :
AWGN channels; error statistics; frequency shift keying; jamming; multi-access systems; multiuser channels; spread spectrum communication; AWGN channel; BER performance; BFSK; DS spread spectrums; DS-SS; DS/SFH-SSMA system; MAI; MTJ; additive white Gaussian noise channel; binary frequency-shift keying; bit error rate; direct-sequence spread-spectrum communication system; independent random variables; jammer-to- signal ratio; jamming signals; jamming tones; maximum overlapping limitation; minimum spacing; multipath fading; multiple-access interference; multitone jamming channel; noncoherent FSK signaling; nonoverlapping system; optimized overlapping system; overlap ratio; overlapping BFSK; phase angles; processing gain; received signals; simulation results; system performance; time delays; AWGN; Additive white noise; Bit error rate; Delay effects; Frequency modulation; Frequency shift keying; Jamming; Multiple access interference; Performance analysis; Random variables;
Journal_Title :
Vehicular Technology, IEEE Transactions on
DOI :
10.1109/TVT.2002.807151