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

Abstract

With the growing use of RFID (Radio Frequency Identification), it is becoming important to devise ways to read RFID tags in real time. Access points (APs) of IEEE 802.11-based wireless Local Area Networks (LANs) are being integrated with RFID networks that can efficiently collect real-time RFID data. Several schemes, such as multipolling methods based on the dynamic search algorithm and random sequencing, have been proposed. However, as the number of RFID readers associated with an AP increases, it becomes difficult for the dynamic search algorithm to derive the multipolling sequence in real time. Though multipolling methods can eliminate the polling overhead, we still need to enhance the performance of the multipolling methods based on random sequencing. To that extent, we propose a real-time cluster-based multipolling sequencing algorithm that drastically eliminates more than 90% of the polling overhead, particularly so when the dynamic search algorithm fails to derive the multipolling sequence in real time.

Efficient MAC protocol for IEEE 802.11 wireless LANs with obstructing objects

“…At the initial time when AP does not have the connectivity information among wireless LAN devices, AP should collect the connectivity information using the PCF * Department of Industrial and Management Systems Engineering, Dong-A University Nakdong-daero, Saha-gu, Busan, Korea, (Point Coordination Function) poling protocol during CFPs (Contention Free Periods). We want to briefly review the method for AP's collecting the connectivity information among wireless LAN devices using the PCF protocol [4]. The connectivity information C i,j between nodes i and j is equal to 1, if device j properly decodes the PHY signal transmitted from device i , and is zero otherwise.…”

“…In this paper, to mitigate the uplink interference from obstructing objects, we compose the multihop shortest path from each wireless LAN device, the transmission signal of which is interfered from obstructing objects, to AP using the connectivity information among wireless LAN devices, and propose the new MAC protocol based on the multipolling method, which efficiently grants the transmission opportunities to wireless LAN devices on shortest paths. The connectivity information among wireless LAN devices were also employed in [4]. In this paper, we assume that the hidden node problem does not exist in wireless LANs.…”

Efficient Node Insertion Algorithm for Connectivity-Based Multipolling MAC Protocol in Wi-Fi Sensor Networks

“…The connectivity-based multipolling MAC protocol was developed to improve the efficiency of the multipolling MAC protocol by reducing the multipolling frame transmissions [1][2][3][4]. Using connectivity and interference information among nodes, a simultaneous polling method was proposed to allow multiple direct data communication between nodes to be carried out [1].…”

“…Frame aggregation and connectivity-based multipolling techniques were combined to efficiently collect Radio Frequency Identification (RFID) tag information from nodes [3]. The combined clustering and sequencing method was proposed for a heuristic approach for deriving the connected multipolling sequence of RFID readers [4]. However, in some cases, a scheduling algorithm based on the Traveling Salesman Problem (TSP) model, which is employed by the connectivity-based multipolling MAC protocol, requires too much time to obtain the minimal number of serially connected multipolling sequences in cases where a large number (e.g., >100) of nodes exist in wireless LANs [1][2][3][4].…”

Enhancing MAC performance of DCF protocol for IEEE 802.11 wireless LANs

“…With the increased number of users of wireless LANs by the new technologies such as IEEE 802.11n and IEEE 802.11ac, and the deployment of WiFi sensors, the research is needed to enhance the MAC performance of wireless LANs [2][3][4][5].…”