Title :
Performances of differential-encoded FFHMA systems with space-frequency coding over Nakagami-m fading channels
Author :
Khemapatapan, Chaiyaporn ; Benjapolakul, Watit
Author_Institution :
Dept. of Electr. Eng., Chulalongkorn Univ., Bangkok, Thailand
Abstract :
The performance and capacities of differential-encoded fast frequency-hopping multiple-access (FFHMA) systems under Nakagami-m fading channels are studied. A space-frequency coding (SFC) scheme is applied to gain diversity order. The proposed FFHMA transmitter can operate without an output hopping filter. The simulation results show that the receiver can detect the transmitted signal when the maximum Doppler frequency closes to 350 Hz. The performance of synchronous FFHMA systems can be improved by spreading factor and average SNR per bit. In a Rayleigh fading channel, the system capacity of FFHMA for BER about 10-3 is derived from simulation and it is about 5, 24, and 61 users for spreading factor of 1, 2, and 4, respectively.
Keywords :
Doppler effect; channel capacity; diversity reception; fading channels; frequency division multiple access; frequency hop communication; space division multiple access; space-time codes; 350 Hz; FFHMA system capacity; Nakagami-m fading channels; Rayleigh fading channel; SFC; SNR per bit; differential-encoded FFHMA systems; diversity gain; fast frequency-hopping multiple-access; maximum Doppler frequency; space-frequency coding; spreading factor; synchronous FFHMA systems; Antenna arrays; Antennas and propagation; Bandwidth; Channel capacity; Fading; Filters; Frequency; Signal detection; Spread spectrum communication; Transmitters;
Conference_Titel :
Vehicular Technology Conference, 2004. VTC2004-Fall. 2004 IEEE 60th
Print_ISBN :
0-7803-8521-7
DOI :
10.1109/VETECF.2004.1404902
