TDMA scheduling problem avoiding interference in multi-hop wireless sensor networks

Abstract

In this paper, we consider a multi-hop sensor network, where the network topology is a tree, TDMA (time division multiple access) is employed as medium access control, and all data generated at sensor nodes are delivered to a sink node (the base station) located on the root of the tree through the network. It is reported that if a transmission schedule that avoids interference between sensor nodes completely can be computed, TDMA is preferable to CSMA/CA (carrier sense multiple access with collision avoidance) in performance. In general, the TDMA scheduling problem to find the shortest schedule is formulated as a combinatorial optimization problem, where each combination corresponds to a schedule. However, solving such a combinatorial optimization problem is difficult, especially for large-scale multi-hop sensor networks. The reason of the difficulty is that the number of the combinations increases exponentially with the increase of the number of nodes. In this paper, to formulate the TDMA scheduling problem, we propose a min-max model and a min-sum model. The min-max model yields the shortest schedule, but it is difficult to solve large-scale problems. The min-sum model does not guarantee providing the shortest schedule; however, it may give us good schedules over a short amount of computation time, compared to the min-max model. Numerical examples show that the min-sum model can provide good schedules in a reasonable CPU time, even when the min-max model fails to compute the shortest schedule in a reasonable CPU time.

Pemodelan Multi-Layer Multihop Routing Protocol Pada Jaringan Wireless Sensor Network

“…Nilai Prx yang ditentukan adalah sebesat -80 dB. Untuk mendapatkan power transmission (Ptx) yang obtimal bisa menggunakan persamaan dibawah ini : (Sasaki, Furuta, Ukai, & Ishizaki, 2016), dalam multihop skala besar TDMA dinilai tidak mampu untuk menangani masalah optimalisasi kombinatorial yang menjadi beban dalam penjadwalan waktu singkat yang disediakan oleh TDMA. Untuk itu dalam penelitian ini peneliti tidak menggunakan node heterogen dalam satu cabang pohon, melainkan memecah pohon multihop tersebut kedalam beberapa cabang seperti terlihat pada ilustrasi dalam gambar 2.…”

A distributed density optimized scheduling function for IEEE 802.15.4e TSCH networks

“…The goal is to maximize the number of labels we attach without causing interference between two conflicting transmissions. Similar problems are defined in the literature, such as in the works of Kodialam and Nandagopal and Sasaki et al; however, they are usually formulated for different scenarios and technologies, and most of the assumptions and objective functions are not comparable. Our approach is focused on IEEE 802.15.e TSCH networks and uses a queue‐based model that maximizes the throughput at the root node by selecting the optimum scheduling configuration at every node by examining the in and outgoing traffic at each queue.…”

Low Duty-Cycling MAC Protocol for Low Data-Rate Medical Wireless Body Area Networks

“…In general, these MAC protocols take the characteristics of all kinds of traffic into consideration and exert two kinds of MAC mechanisms, CSMA/CA (carrier sense multiple access with collision avoidance) [22] and TDMA (time division multiple access) [23], to adapt to all sorts of traffic. Both mechanisms have their advantages and drawbacks.…”

“…Many MAC protocols, e.g., DQBAN (Distributed Queuing Body Area Network protocol) [ 13 ], EELDC-MAC (Energy-efficient Low Duty Cycle MAC protocol) [ 14 ], Med-MAC (Medical MAC protocol) [ 15 ], BodyMAC [ 16 ], TDMA-based-MAC [ 17 ], IEEE 802.15.4 [ 18 ], IEEE 802.15.6 [ 19 ], priority-based MAC [ 20 ], on-demand MAC [ 21 ], etc., have been proposed to support WBANs. In general, these MAC protocols take the characteristics of all kinds of traffic into consideration and exert two kinds of MAC mechanisms, CSMA/CA (carrier sense multiple access with collision avoidance) [ 22 ] and TDMA (time division multiple access) [ 23 ], to adapt to all sorts of traffic. Both mechanisms have their advantages and drawbacks.…”