Random Access Mechanism Enhancement Based on a Hybrid ALOHA Protocol Using an Analytical Model.

In this paper, we present a new MAC (Medium Access Control) protocol, called Hybrid ALOHA (H-ALOHA), which is a combination of two existing protocols: Pure ALOHA (P-ALOHA) protocol and Slotted ALOHA (S-ALOHA) protocol. The idea behind it is to design a MAC protocol that could meet some specific requirements in wireless networks, such as reducing energy consumption, delay minimization, and increasing the throughput. To the best of our knowledge, the S-ALOHA protocol is an improved version of P-ALOHA. However, during one single transmission scenario, P-ALOHA works better than S-ALOHA in terms of energy consumption and packet delivery. Motivated by that fact, we combine these two protocols, resulting in a hybrid ALOHA. A finite-state Markovian model is proposed to study the steady-state performance of H-ALOHA including normalized throughput, backlogged throughput, access delay, backlogged delay, and energy consumption. The proposed hybrid protocol has been compared with the S-ALOHA protocol. The simulation results show that the proposed hybrid protocol outperforms all ALOHA protocols. On average, the proposed protocol outperforms the S-ALOHA protocol by 60% in terms of normalized throughput, by 15% in terms of access delay, and by 23% in terms of total energy consumed during the transmission process.