How do Wireless Chains Behave? The Impact of MAC Interactions

In a Multi-hop Wireless Networks (MHWN), packets are routed between source and destination using a chain of intermediate nodes; chains are a fundamental communication structure in MHWNs whose behavior must be understood to enable building effective protocols. The behavior of chains is determined by a number of complex and interdependent processes that arise as the sources of different chain hops compete to transmit their packets on the shared medium. In this paper, we show that MAC level interactions play the primary role in determining the behavior of chains. We evaluate the types of chains that occur based on the MAC interactions between different links using realistic propagation and packet forwarding models. We discover that the presence of destructive interactions, due to different forms of hidden terminals, does not impact the throughput of an isolated chain significantly. However, due to the increased number of retransmissions required, the amount of bandwidth consumed is significantly higher in chains exhibiting destructive interactions, substantially influencing the overall network performance. These results are validated by testbed experiments. We finally study how different types of chains interfere with each other and discover that well behaved chains in terms of self-interference are more resilient to interference from other chains

Застосування методів диференціального та інтегрального числення до розв’язання задач технічного змісту. Методичні вказівки для самостійної роботи студентів напрямів підготовки 6.050301 Гірництво, 6.050101 Комп’ютерні науки, 6.040103 Геологія, 6.050502 Інженерна механіка

Мета методичних вказівок – конкретизувати приклади, які розв’язуватимуть студенти при вивченні розділу “Диференціальне та інтегральне числення функції однієї змінної”, а також надати допомогу їм у засвоєнні методів математичного дослідження прикладних задач, що дуже важливо для майбутніх інженерів. Наведено 80 задач технічного змісту. Всі вони забезпечені відповідями та вказівками до їх розв’язання. Необхідні відомості з теорії подано у довідковій формі. Можуть бути використані студентами для самостійної роботи, а також викладачами для проведення практичних й індивідуальних занять та занять студентського математичного гуртка

Modeling and Analysis of Two-Flow Interactions in Wireless Networks

Interference plays a complex and often defining role in the performance of wireless networks, especially in multi-hop scenarios. In the presence of interference, Carrier Sense Multiple Access MAC protocols are known to suffer from the hidden terminal and exposed terminal problems, which can cause poor performance and unfairness. In this paper, we examine the possible interference modes arising among two interfering one-hop connections under a Two-Disc model of interference. We classify the large set of resulting configurations into five categories and develop closed form expressions to compute their probability of occurrence. The analysis exposes two new categories, whose occurrence is common, and whose behavior differs significantly from the three known interference categories. Further, the frequency of occurrence of the categories differ significantly from existing results (obtained with a simpler unit disc model of interference). We develop throughput estimation models for the different categories and validate them using simulation

Modeling and Analysis of Two-Flow Interactions in Wireless Networks

Interference plays a complex and often defining role in the performance of wireless networks, especially in multi-hop scenarios. In the presence of interference, Carrier Sense Multiple Access MAC protocols are known to suffer from the hidden terminal and exposed terminal problems, which can cause poor performance and unfairness. In this paper, we examine the possible interference modes arising among two interfering one-hop connections under a Two-Disc model of interference. We classify the large set of resulting configurations into five categories and develop closed form expressions to compute their probability of occurrence. The analysis exposes two new categories, whose occurrence is common, and whose behavior differs significantly from the three known interference categories. Further, the frequency of occurrence of the categories differ significantly from existing results (obtained with a simpler unit disc model of interference). We develop throughput estimation models for the different categories and validate them using simulation