Adaptive k-cast Scheduling for High-Reliability and Low-Latency in IEEE802.15.4-TSCH

Abstract

The Industrial Internet of Things tends now to emerge as a key paradigm to interconnect a collection of wireless devices. However, most industrial applications have strict requirements, especially concerning the reliability and the latency. IEEE802.15.4-TSCH represents currently a promising standard relying on a strict schedule of the transmissions to provide such guarantees. The standard ISA-100.11a-2011 has proposed the concept of duocast, where a pair of receivers are allocated to the same transmission opportunity to increase the reliability. In this paper, we generalize this approach to involve k different receivers, and we explore the impact of this technique on the performance of the network. We propose an algorithm assigning several receivers for each transmission to increase the probability that at least one device receives correctly the packet. By exploiting a multipath topology created by the routing layer, we are able to reduce the number of transmissions while still achieving the same reliability. We consequently increase the network capacity, and reduce significantly the jitter. Our simulation results highlight the relevance of this k-cast technique in TSCH for the Industrial Internet of Things.

IEEE 802.15.4.e TSCH-Based Scheduling for Throughput Optimization: A Combinatorial Multi-Armed Bandit Approach

“…In almost all previous TSCH scheduling, authors either assume that the impact of link qualities or channel variations on performance are negligible (such as [7][8][9][10][11][12][13][14]), or that the instantaneous and complete channel information is available (such as [15][16][17]), or else the channel is modeled quasi-static (such as [18][19][20]). For example, in [15 and 16], it is assumed that the instantaneous CSI is fully measurable and available, therefore one can use an offline method and calculate the optimal scheduling for a TSCH network by the exact rate of packets to be sent over each link.…”

“…In [18], a k-cast scheduling is introduced for TSCH networks, where k different receivers are allocated to the same transmitter in order to increase the probability that at least one device receives the packet correctly. In this method, the reliability is improved by using a multi-path routing approach.…”

“…To the best of our knowledge, there are many studies which present new scheduling methods for TSCH networks without considering the impact of CSI (such as [7][8][9][10][11][12][13][14]). We have seen that in some schemes authors assume that perfect non-causal knowledge of CSI is available for the scheduling process (such as [15][16][17]) and in others prior statistical knowledge of link qualities is utilized in order to improve performance (Such as [18][19][20]). Although such assumptions in earlier scheduling algorithms, where channel status is available or constant, enable mathematical tractability of the scheduling problem, they are not realizable in real-world systems due to the difficulty in predicting random and timevarying wireless channel conditions.…”

Is Link-Layer Anycast Scheduling Relevant for IEEE 802.15.4-TSCH Networks?

“…A set of receivers is then subscribing to this anycast address, waking-up simultaneously. Hosni et al [5] demonstrate that picking the best parents (higher PDR) represents an optimal strategy when neglecting the overhead for notifying the transmitter the packet was correctly decoded. However, they assume that packet loss probabilities are independent for all the links, which may not hold practically.…”

“…Since a transmission is lost only if all receivers fail to receive a packet, the network reliability and the energy efficiency can be significantly improved [4]. Hosni et al [5] investigated the impact on the reliability when choosing the best parents to forward the packets. However, they assume that packet loss probabilities are independent for all the links, which may not hold practically.…”