الفهرس 
Modified_Slotted_ALOHAOnly 14 pages are availabe for public view
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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.