MAC protocol for wireless ATM: contention free versus contention based transmission of reservation requests

Abstract

In general, the users of wireless ATM terminals request the same functionality and Quality of Service as users of wired terminals. These user requirements can be transfomed into the demand for building an ATM multiplexer around the air interface which is characterized by a radio channel inside the ATM layer. The main difference between this logical ATM multiplexer around the air interface and a normal ATM multiplexer is the distribution of the multiplexing function between wireless terminals and the base station. For the uplink this requires a frequent notification of the ATM cell scheduler in the base station about the status of the incoming queues inside the wireless terminals. This paper focuses on different transmission methods for transmitting capacity request messages (also designated as reservation request) over the uplink.

Study of various TDMA schemes for wireless networks in the presence of deadlines and overhead

“…Thus, the dropping rate function will never reach a zone of exponential behavior and will always be (lossly) lower bounded by . 7 Whether the overhead or the variance dominates the dropping rate will depend of their relatives values.…”

“…They employ a data link control (DLC) layer to combat the unreliability of the wireless link and a medium access control (MAC) protocol to organize the sharing of the multiaccess channel. MAC's for WATM have been examined in [4] and [7]- [11]. They all employ time division multiple access (TDMA) with on-demand assignment of the transmission resources by a central agent or scheduler.…”

“…In a dynamic wireless environment though, the scheduler needs to be communicated by the distributed users of their demands for resources, as well as inform the users of its decision (slot assignment). This communication takes place at discrete points in time [4], [7]- [11], and it is not continuous due to communication resource limitations. It is implemented by employing various mechanisms such as a control channel, piggy-backing on information bearing cells, and polling procedures; such mechanisms introduce some overhead in the system.…”

“…For = 1, d I r=T 0In (T 0 In) does not converges to a finite value as T ! +1 7. For large values of T and < 1, the lower bound of (14) becomes negative (meaningless).…”