Wireless ATM Access Networks: a Coordinated ATM/MAC Strategy for Traffic Control

摘要

This paper presents and evaluates a traffic control strategy for wireless ATM networks with TDMA multiplexing. This strategy is implemented as a part of the Medium Access Control protocol and allocates the radio resources on the air interface taking advantage of a strong co-ordination between the Medium Access Control and the ATM signaling and traffic management protocols to achieve an efficient support of all the aTM service categories and meet the ATM Quality of Service requirements. The scheduling policies for ATM switches are applied to regulate the transmissions to the wireless terminals and a new strategy, called Credit on-Demand Centralized Allocation policy (CDCA) is proposed to co-ordinate the transmissions from the wireless terminals. CDCA allocates the transmission opportunities on a per-connection basis and keeps track of the status of the ATM connections by means of in-band updates. The operation of CDCA is specified with reference to the handling of the ABR service category: four solutiosn are defiend, that differ in the allocation of the transmission opportunities. These are evaluated by means of computer simulation for different traffic configurations and the results gives useful guidelines to select the most appropriate solution.