Polling schemes are an important class of medium access control (MAC) protocols for wireless local area networks (WLANs). A major drawback of these schemes is their inefficiency when only a small number of mobile stations have packets to transmit. This inefficiency is due to the polling of mobile stations with no packets to transmit, which delays the transmissions of mobile stations with packets. In this paper, we suggest a new polling MAC which exploits the capture phenomena and enables simultaneous polling and transmissions of information packets. Mathematical analysis and simulation results show that the new MAC overcomes the above inefficiency considerably, and thus it is more efficient in the sense that it enables higher throughput and a lower access delay. For example, we show scenarios in which the average access delay is reduced by about 30% and the throughput increases by 66%-75%.

In slotted, dual-bus systems, M stations are connected to two unidirectional buses in a linear order and transmissions use slots passing through the stations. If a slot is used by a station i to transmit to a station j, j>i, then the slot can be reused by a station k, k/spl ges/j. We show that the necessary and sufficient length of addresses for full slot reuse is M-2 bits for w=0 and [(M-1)/2/sup w-1/]+w-2 bits for w/spl ges/1 and M>1+2/sup w/, where w is the bit delay at every station.

This paper suggests a CSMA/CD compatible MAC protocol for real-time transmissions in a home or small office local area network. It has the key advantage of allowing devices implementing the existing Ethernet protocol such as PCs, printers and ISDN routers to operate with devices implementing the new MAC. The new MAC enables real-time traffic such as digital video and audio to be transmitted with low delay and jitter.

In slotted, dual-bus systems, stations are connected to two unidirectional buses in a linear order and transmissions use slots passing through the stations. If a slot is used by a station to transmit to a station , , then the slot can be reused by a station , . We show that the necessary and sufficient length of addresses for full slot reuse is bits for and bits for and , where is the bit delay at every station.

The DQDB is the IEEE 802.6 MAC standard protocol for metropolitan area networks (MANs). It is designed for the slotted, dual bus configuration. A simple way to improve the performance of the DQDB is to perform slot reuse and many methods have been suggested in the past to efficiently incorporate slot reuse with the DQDB. However, some of them can lead to starvation. We improve one of these previous suggestions and the main contribution of the paper is that for the first time we also provide a proof that the improved scheme ensures a lack of starvation. We also specify this proof for the important case of the DQDB without slot reuse.

Slot reuse is a simple method to improve the efficiency of MACs designed for the slotted, dual bus configuration. The authors propose several schemes for the assignment of throughput to stations in this configuration, taking into account slot reuse and assuming uniform traffic. The criteria for comparison of the schemes are throughput gain, worst message queueing and access delays at stations and the fraction of blocked messages. It turns out that the throughput gain in the scheme in which every station receives the same throughput is relatively low but it is the most attractive scheme is relation to the other criteria.>

Slot reuse is a simple method to improve the efficiency of MACs designed for the slotted, dual bus configuration. The authors propose several schemes for the assignment of throughput to stations in this configuration, taking into account slot reuse and assuming uniform source destination distribution. The criteria for comparison of the schemes are throughput gain, worst averages of message queueing and access delays at stations and the fraction of blocked messages. On the average, it turns out that the scheme in which every station receives the same throughput is very attractive.>

Several schemes for slot reuse in CRMA are studied. A major challenge in CRMA is to incorporate slot reuse together with continuous message transmissions, i.e., to ensure that every message is transmitted in a stream of contiguous slots on the bus. Schemes based on the ideas of erasure nodes and destination release are developed and simulation results are presented.>

A simple scheme for slot reuse without latency for the dual bus configuration is studied. The scheme relies on information read in the previous slot and will be referred to as previous slot information (PSI) slot reuse. The scheme requires a minimal addition to the station hardware and its reliability is high. The efficiency of PSI is checked over a wide range of parameters and is found to be almost as good as destination release. The scheme can be implemented with or without the addition of erasure nodes.>