Time Division Multiple Access Protocol for a Fiber-Optic Passive Double Star Transport System

Noriki MIKI  Kiyomi KUMOZAKI  

IEICE TRANSACTIONS on Communications   Vol.E78-B   No.7   pp.995-1001
Publication Date: 1995/07/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Multimedia Computer Networks)
fiber-optic access network,  passive double star architecture,  time division multiple access,  ranging and polling,  

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This paper describes a flexible point-to-multipoint access protocol for the fiber-optic passive double star (PDS) system. To provide various types of services, and permit flexibility in changing transport capacity, a time division multiple access (TDMA) scheme for the PDS system is considered. Dynamic time slot multiplexing based on TDMA is proposed to provide required time slots efficiently according to service changes. The effectiveness of dynamic time slot multiplexing is calculated and compared to fixed time slot multiplexing for telephony services. A TCM/TDMA frame structure and an access protocol enabling dynamic time slot multiplexing are proposed. ONU bandwidth is dynamically assigned by using a set of pointers. The ONU access protocol causes no interruption to operating ONUs on the same PDS system during the configuration or reconfiguration of an ONU. The access time is analyzed to estimate the performance of the access protocol. The probability density of access time is calculated for the number of ONUs connected. The calculation results indicate that a PDS system can accommodate up to around 60 ONUs within the maximum access time specified by ITU-T. The experimental results also agree fairly well with the theoretical values.