MAC Protocol In Broadband PON

The demand for accessing Internet with high speed and supporting multi-media applicayion has greatly accelerated development of broadband access networks. At present ,from xDSL to HFC, several alternatives are considered for the position of broadband service in th local loop. However, they are all expediencies, to a long-term viewpoint. In the field of wired solutions, passive optical networks (PON) looks verying promising due to their bandwidth capacity.The passive optical networks based on ATM combine the ATM's statistic multiplexing function with PON's broadband transparent transmission.APON have a great of vitues, such as big capacity, reasonable ratio of performance and price, and easy to upgrade. Compared with ATM, ethernet has more convenience.But there are some technical or theoretical problems in both APON and EPON, such as rangeing, burst mode optical receipt, burst synchronization and dynamic bandwidth allocation. This dissertation focuses on study and design of media access control (MAC) protocol for passive optical network.Firstly, we briefly present the researching and developing status of modern telocom networks and broadband access network and indicating the importance of developing PON. In chapter 2, we introduce the structure and requirement of PON. In chapter 2, at the beginning, we introduce the configuration and requirement of PON, then we expatiate on the three functional blocks in detail. At last, we describe what the key technologies are for APON.Compaired with other media-shared network, APON's tree-like topologyhas its own characteristics that impose particular requirements on MAC protocol. As media-shared network, APON needs some form of Media Access Control (MAC) protocol to arbitrate the upstream channel among termination, and avoid collisions. The Media Access Control (MAC) protocol plays an important role in the whole communication system, and effect performance of the system with great significance. So it's the kernel in APON access system. A kind of MAC protocol is designed in this dissertation, through whitch we can satisty the requirment of real-time sercices and non real-time services' requirement. The former is sensitive to cell delay (CD) and cell delay variable (CDV), the latter is sensitive to cell lose rate (CLR).In chapter 4, the EPON's upstream access process is analyzed in this thesis, at the same time, we disscuss the developing direction's of PON.The main contributions of this dissertation can be briefly summarized as fellow:The MAC whitch is fit for APON's tree-like topology is studied by theoretical analysis and computer simulation. Results show that when the total load is from 0.75 to 0.94, the delay and jitter of severices are controlled with 0.5ms and 0.15ms respectively.The MAC protocol which is fit for EPON is discussed theoretically on the basis of Ethernet thecology.