Predictive channel access scheme for Wireless Sensor Networks using Received Signal Strength statistics

Abstract

Number of indoor Wireless Sensor Network (WSN) applications are increasing day by day. However, there are many interferers (like 802.11x and 802.15.4 devices) effecting 2.4 GHz band.Moreover, co-existence is a bigger challenge for WSNs because of their tiny structure and resource constraints. In this paper, a novel method is proposed to predict the near future channel quality using the statistical channel noise history. By using the prediction method, WSN node channel access can be scheduled when the channel is free in order to increase performance. In this paper, first, noisy channels are analyzed to find a prediction metric. Then, with the help of the prediction algorithm developed, channel access is performed. The results obtained from the test bed show that our approach incurs up to 60% to 90% reduction in noisy channel access which satisfies less packet loss and less interference with non-WSN communications.

PRESCIENT: A predictive channel access schemefor IEEE 802.15.4-compliant devices considering IEEE 802.11 coexistence

“…In the evaluations PRESCIENT will be compared with 3 other schemes: 1) IEEE 802.15.4 with static channel access, 2) IEEE 802.15.4 with random channel access, and 3) predictive channel access using the clustered RFSS [17]. PRESCIENT and the first two channel access schemes are implemented by using identical transceivers and their channel access performance are evaluated using the test bed described in Section 2.…”

“…PRESCIENT and the first two channel access schemes are implemented by using identical transceivers and their channel access performance are evaluated using the test bed described in Section 2. Because the predictive channel access using the clustered RFSS [17] scheme cannot be embedded in real IEEE 802.15.4-compliant hardware, CCA measurements of the test bed are logged and then the results are gathered by offline processing of the logs. During the tests, the nodes have to transmit 1 packet every 100 ms.…”

“…In a static channel access scheme, the transmitter node accesses the channel and sends its packet every 100 ms. Random channel access schemes differ from the first scheme in terms of channel access decisions where the channel access is scheduled according to uniform distribution within 100 ms intervals. Finally, in PRESCIENT and predictive channel access using the clustered RFSS [17] (in short, Clustered RFSS), the channel access is scheduled to the instant with the lowest weight value. In Table 1, the performance of PRESCIENT gathered from Pair 1 and Pair 2 is compared with the other schemes in terms of free channel access performance where f −1 s = 10 ms, N = 1000, L = 120, and λ = -80 dBm.…”

“…Given the rapid increase in the number of devices communicating in the 2.4 GHz ISM band, it is clear that innerchannel interference needs to be addressed to improve the coexistence performance. In our previous work [17], we proposed a scheme to address the innerchannel interference problem, which used clustering techniques to enhance the free channel access performance of IEEE 802.15.4-compliant devices. In that work, we showed that the proposed scheme can provide significant coexistence performance improvement.…”

Analysis of So Bo Effect on Collision in Ire 802.15.4 Wireless Sensor Networks

“…Slotted CSMA is for beacon enabled mode and Unslotted CSMA if for beaconless mode. In non-beacon enabled mode all nodes can send their data by using an unslotted CSMA/CA mechanism, which does not provide any time guarantees to deliver data frames [3]. In a beacon-enabled mode, a PAN coordinator periodically generates beacon frames and slots are provided for data transmission.…”