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

Usually, in the slotted ALOHA system using a multibeam adaptive array, separate detection of colliding packets is carried out from the shift of PN code due to the difference in arrival time. In this paper, unlike the usual method, a method for separate detection of colliding packets is proposed in which each user randomly selects a PN code among several alternatives. As a result of the evaluation of the throughput by computer simulation, it is found that a high throughput can be obtained without consideration of arrival‐time difference in the proposed method with only code selection as the separation condition, even though packet collision occurs due to identical PN code. Therefore, by restraining the increase of the preamble length, the transmission efficiency can be improved. In the case of 16 codes and 4 elements, the throughput is about 2.2, constituting significant improvement. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(9): 69–77, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1127