China
Africa
Explore chapters and articles related to this topic
Quality of Service MAC for Wireless Sensor Networks
Published in Shafiullah Khan, Al-Sakib Khan Pathan, Nabil Ali Alrajeh, Wireless Sensor Networks, 2016
Bilal Muhammad Khan, Rabia Bilal
The hidden node problem occurs in Carrier Sense Multiple Access (CSMA) protocols in which a node senses the medium before the start of transmission. If the medium is found to be busy, the node defers its transmission to avoid collision and retransmission. Figure 10.1 gives a typical scenario for hidden node problem. There are three nodes A, B, and C in the network. The arrangement of the nodes is such that node A and node B are in communication range as well as node C and node B; however, node A and node C are out of communication range from each other. Assuming that node A starts to communicate data packets toward node B, after some time, node C senses the channel and finds it idle as it is out of the communication range of node A, and it also starts to transmit packets toward node B resulting in collision due to hidden node. Using simple CSMA MAC protocol in such a scenario leads to collision and needless retransmission of data packets.
Performance Evaluation of Co-Channel Interference on Wireless Networks
Published in Journal of Computer Information Systems, 2022
Joong-Lyul Lee, Joobum Kim, Myungjae Kwak
Many researchers have been studying interference phenomena and its performance degradation in IEEE 802.11 and 802.15 wireless networks. In IEEE 802.11 wireless networks, the hidden node problem occurs when two senders are located outside the communication range of each other and communicate with a wireless AP. The exposed node problem occurs when two receivers are located out of communication range of each other, and two senders are located within the communication range. In Ng et al.12, the authors conducted real-network experiments to investigate the impact of hidden nodes in IEEE 802.11b wireless networks. The results of these experiments show throughput degradation related to the hidden node problem and the ineffectiveness of RTS/CTS to solve the hidden node problem. To evaluate the effects of ACI in 802.11 networks under the exposed terminal and hidden terminal scenarios, the authors performed extensive measurements, and their results show that interference still exists between the two nodes even though they are operating on non-overlapping channels.3,4 Zubow et al.5 conducted ACI experiments on IEEE 802.11n networks and analyzed the adverse effects. IEEE 802.11 and IEEE 802.15.4 wireless networks use the same 2.4 Ghz frequency range. Paruchuri et al.6 presented the interference effects of WLAN and Bluetooth on IEEE 802.11b networks and found the performance was worse with ACI than with CCI at lower SNR. In Shin et al.7, the authors evaluated the effect of mutual interference on the performance of IEEE 802.15.4 and IEEE 802.11b networks. Jihwane et al.8 represented an analytical throughput model on co-existing IEEE 802.11b with IEEE 802.15.4a networks in the 2.4 Ghz. In Liese et al.9, the authors conducted experiments on IEEE 802.11b wireless mesh network and have characterized an IEEE 802.11b wireless mesh network.