An analytic model for enhancing IEEE 802.11 point coordination function media access control protocol

Abstract

The design of media access control (MAC) protocol that can efficiently support the real-time applications in Wireless Local Area Networks (WLANs) is a challenging task, it requires that the MAC layer provide strict delay guarantees for sensitive traffic, the Point Coordination Function (PCF) with Round Robin (RR) polling scheme has been included in IEEE 802.11 MAC protocol to achieve this objective. However, the RR scheme seems difficult to guarantee QoS and satisfy the low delay of the sensitive traffic, yet it can hardly differentiate from priority service for the key station. Thus we utilize an analytic model with two-level-polling mechanism to enhance the RR scheme, and the comparison results show us that the efficiency as well as impartiality of proposed scheme is better than that of the RR scheme.

On Two-Level State-Dependent Routing Polling Systems with Mixed Service

“…It is worth considering whether the state-dependent mechanism improves the performance of the system comparing with the existing two-level polling systems. In order to answer this question, we compare a classical two-level system with switch-over time [6], abbreviated as classical system and a parallel two-level system [8], abbreviated as parallel system in Figure 2. The service discipline in the comparisons is 1limited service for normal queues and exhaustive service for the key queue.…”

“…The reason for this may lie in the fact that the analysis of state-dependent routing polling model is much more complex than that of cyclic polling model, especially in priority differentiated model. In particular, waiting time and queue length analysis of two-level priorities polling systems can be found in [5][6][7], in which the server visits queues in a two-level route; that is, the server polls key queue with exhaustive scheme after each gated service to normal queue [5]. This work is extended in [6] with assigning 1-limited service discipline to normal queues.…”

“…In particular, waiting time and queue length analysis of two-level priorities polling systems can be found in [5][6][7], in which the server visits queues in a two-level route; that is, the server polls key queue with exhaustive scheme after each gated service to normal queue [5]. This work is extended in [6] with assigning 1-limited service discipline to normal queues. More recently, Yang et al set the exhaustive service for normal queue and gated service for key queue to ensure fairness but just acquire the first moment performance of the system as mean queue length at the polling epoch and the mean cyclic time [7].…”

Cluster-Based Multipolling Sequencing Algorithm for Collecting RFID Data in Wireless LANs

“…According to the polling scheme of the PCF protocol, APs (Access Points) transmit separate polling frames to grant the transmission opportunities to the stations in a round-robin manner. To enhance the QoS (Quality of Service) capability of the PCF protocol, the various new MAC protocols including the priority polling scheme, the weighted polling scheme, the HCCA (HCF Controlled Channel Access) protocol and the two-level polling mechanism in Refs [4]- [7] have been proposed in the literature. To reduce transmissions of PCF polling frames, we can consider a multipolling scheme, where multiple stations can be granted the transmission opportunities by a single multipolling frame when the APs find multiple stations sequentially connected using the connectivity information among the stations.…”

The Application of the Exhaustive Polling Theory in Intelligent Traffic System

“…Intelligent traffic light [2] theory is not only focus on ensure the orderly safe passage of vehicles and pedestrians with the same rules of ordinary traffic lights, more is control the waiting time intelligently in order to improve the traffic efficiency under the background of increasing traffic pressure,.…”