Random preamble code selection for slotted ALOHA radio network with a multibeam adaptive array

This paper proposes random code selection for a slotted ALOHA radio network with a multibeam adaptive array, which can decompose and detect the packets from the collision ones. The multibeam adaptive array requires that the multiple references are uncorrelated with each other. The aim of our proposal is to realize quasi-user-own preamble, which can be known by the communication server (CS) in advance. When packet transmission, each user selects a code from several available codes, randomly. Then, most of the packets have unique codes. In this paper, the throughput performance and code collision effect of the proposed system are investigated. Computer simulations show that the obtained maximum throughput reaches almost 2.2 with a 4-element adaptive array and 16-code selection even under the code collision condition