Title :
Performance analysis of DS/SSMA unslotted ALOHA system with variable length data traffic
Author :
So, Jae-Woo ; Han, Il ; Shin, Byung-Cheol ; Cho, Dong-Ho
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Korea Adv. Inst. of Sci. & Technol., Seoul, South Korea
fDate :
11/1/2001 12:00:00 AM
Abstract :
We analyze the throughput of a direct-sequence spread spectrum multiple access (DS/SSMA) unslotted ALOHA system with variable length data traffic. The system is analyzed for two cases: (1) systems without a channel load sensing protocol (CLSP) and (2) systems with a CLSP. The bit-error probability and the throughput are obtained as a function of the signal-to-noise ratio (SNR) during message transmission, considering the number of overlapped messages and the amount of time overlap. We assume that the generation of data messages is Poisson distributed and that the messages are divided into packets before transmission. The system is modeled as a Markov chain under the assumption that the number of packets in a message is geometrically distributed with a constant packet length. The throughput variance of the DS/SSMA unslotted ALOHA system with variable length data traffic is obtained as the Reed-Solomon code rate varies. Results show that a significant throughput improvement can be obtained by using an error-correcting code
Keywords :
Markov processes; Poisson distribution; Reed-Solomon codes; access protocols; code division multiple access; data communication; error statistics; land mobile radio; multiuser channels; noise; packet radio networks; spread spectrum communication; telecommunication traffic; DS/SSMA unslotted ALOHA system; Markov chain; Poisson distribution; Reed-Solomon code rate; SNR; bit-error probability; channel load sensing protocol; data message generation; direct-sequence spread spectrum multiple access; error-correcting code; geometrical distribution; message transmission; overlapped messages; packet transmission; performance analysis; signal-to-noise ratio; third-generation mobile communication systems; throughput analysis; throughput variance; time overlap; variable length data traffic; Forward error correction; Interference; Mobile communication; Multiaccess communication; Performance analysis; Protocols; Signal to noise ratio; Spread spectrum communication; Throughput; Traffic control;
Journal_Title :
Selected Areas in Communications, IEEE Journal on
