Performance Evaluation of Framed Slotted ALOHA with Reservation Packets for M2M Networks

In the near future, it is expected that a large number of machine-to-machine (M2M) communication devices will provide with ubiquitous information and services. Random access protocols like ALOHA ans CSMA have been considered for M2M networks for their simplicity of operation. This paper evaluates the performance of a Frame Slotted-ALOHA protocol that deploys reservation and data packets (FSA-RDP), in a scenario where a controller node collect data packets transmitted by a finite number of M2M devices. In FSA-RDP, frames of variable length are divided in two parts, the reservation and data subframes. During the reservation subframe, active devices send short reservation packets to the controller. The controller assigns reserved slots in the data subframe to those devices that succeeded with the reservation. Two queue disciplines are considered, the First In First Out - Blocking (FIFO-BL) and the Last In First Out - Push-Out (LIFO-PO). We develop a discrete time Markov chain to derive the protocol efficiency. For the FSARDP protocol, we also derive the cumulative distribution function of the delay for data packets that are successfully transmitted, when deploying both queue disciplines. Numerical results show that the protocol efficiency of FSA-RDP is between one and two orders of magnitude larger than the efficiency of the conventional Frame Slotted ALOHA. In addition, we show that the difference between the packet delay for FIFO-BL and LIFO-PO is only significant in scenarios with high load and high collision rate.