A New Polling-Based Dynamic Slot Assignment Scheme for Broadband Wireless Access Systems

Fusao NUNO

IEICE TRANSACTIONS on Communications   Vol.E82-B    No.12    pp.2031-2040
Publication Date: 1999/12/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Multimedia Mobile Communication Systems)
DSA,  centralized control system,  wireless access,  

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This paper proposes a new polling-based dynamic slot assignment (DSA) scheme. With the rapid progress of wireless access systems, wireless data communication will become more and more attractive. In wireless data communication, an efficient DSA scheme is required to enhance system throughput, since the capacity of radio links is often smaller than that of wired links. A polling-based DSA scheme is typically used in centralized slot assignment control systems. It, however, is difficult to assign the slots to the targeted mobile terminals in a fair-share manner if only a polling-based scheme is used, especially in unbalanced-traffic circumstances, as revealed later. To solve this problem, we propose the exponential decreasing and proportional increasing rate control as is employed in available bit rate (ABR) service in ATM so that fair slot assignment is achieved even in heavily-unbalanced-traffic circumstances. Moreover, so that an AP operating with a large number of MTs can avoid long transmission delays, a polling-based resource request scheme with random access is featured in a new algorithm. Simulations verify that the proposed scheme offers fair slot assignment for each user while maintaining high throughput and short delay performance.