  In a densely deployed distributed wireless network, there may be various
types of traffic with differentiated Quality of Service (QoS) requirements.
However, when the network is heavily loaded, the collision increases
significantly, making it difficult to guarantee the QoS of traffic. Designing
an efficient Medium Access Control (MAC) protocol to guarantee the QoS of
different types of traffic is an essential research direction. Channel
reservation mechanism is a promising approach to improving QoS. However, few
studies have focused on the channel reservation mechanism for differentiated
traffic. It is difficult to take into account both the QoS of real-time traffic
and the collision issue for ordinary traffic. To address this issue, this paper
proposes the Differentiated Service Guarantee Adaptive Reservation Mechanism
(DSGARM) protocol. A hybrid reservation mechanism is proposed by combining the
absolute reservation mechanism and the relative reservation mechanism. The
absolute reservation mechanism is adopted for real-time traffic. Meanwhile, the
relative reservation mechanism is adopted for ordinary traffic. An adaptive
algorithm is proposed to calculate the reservation parameters that meet the
delay requirements based on the network conditions. The proposed work can be
widely applied in the densely deployed distributed wireless network with
differentiated QoS requirements. In addition, this paper establishes a
mathematical model for the proposed mechanism and theoretically analyzes the
performance. Simulations verify that the mathematical model provides a good
approximation of the protocol performance and demonstrates the advantages of
the proposed protocol.
