الفهرس | Only 14 pages are availabe for public view |
Abstract The high throughput, the time saving, and the lower energy consumption are fundamental issues that draw in the consideration of the Underwater Wireless Sensor Networks (UWSNs) field specialists. Medium Access Control (MAC) protocols in the UWSNs, especially random access protocols are significant methods used to increase the network lifetime and to decrease the consumption rate of energy. ALOHA protocol, a class of random access MAC protocols, is considered as the precept of all the complex designs of MAC protocol such as multi-channel networks. The proposed work is to improve the execution of the ALOHA protocol. In this thesis, we proposed three new protocols to handle the Underwater Wireless Sensor Network issues which are modification of ALOHA protocol. The first proposed protocol, which is called Modified_Slotted_ALOHA, depends on not sending any data unless the slot time starts to avoid collision of data. This protocol uses the back off technique and the buffer, which has a positive role in keeping a copy of the transmitted data, until receiving a delivery acknowledgment. If no acknowledgment is received, the data is resent. Otherwise, the data copy is deleted from the buffer to start preparing other data for transmission. The second proposed protocol is called Slotted-Buffering-ALOHA. It handles the energy consumption process. This protocol explores the state of the communication channel using the Carrier Sense (CS) factors to ensure that the communication channel is free of any data. Also, this protocol uses the same factors used in the previous protocol, such as (slot time, back off technique, and the buffer). The final protocol, named Buffering_Slooted_ALOHA protocol. It treats the network through a new topological strategy by dividing it into small parts using clustering. The network is constructed as a set of closed clusters. Each closed cluster contains small parts of clusters. The data are sent from nodes in a cluster towards the UW-sink located with them into the same cluster or toward UW-main sink located within the general2 network based on slot time only. Moreover, each node has a buffer that holds the transmitted packets until getting their acknowledgment. This buffer has a large capacity to store a lot of packets. To support our claim, some experiments have been accomplished and simulation results demonstrate the validity and effectiveness of the proposed work compared with other different literature methods. |