Static and Dynamic Retransmission Control for Slotted Aloha in Transmission Channels with Erasure and Capture

Kurzfassung

Slotted Aloha can be an attractive multiple access scheme for mobile radio applications, mainly for mobile satellite services. This is especially so when capture-effects occur, i.e. when one out of several colliding data packets can capture the common receiver. Mostly this is due to varying signal levels of the transmitters. It is well-known that a slotted Aloha channel can become unstable. It performs acceptably only if a good retransmission control policy is applied. In this paper, static and dynamic stabilization methods for slotted Aloha in transmission channels with capture and erasure are compared. They are analyzed by analytical methods as well as by simulation. It turns out that a dynamic control procedure is more flexible and outperforms a static retransmission policy also in mobile radio channels.