Slotted ALOHA Filtered Tree (SAFT) for a Reliable LTE RACH

Medium access research has built upon the Poisson arrival assumption since the foundation of ALOHA. However, synchronous transmissions of mobile devices enforce a new bursty arrival type that opens opportunities for design decisions. These bursty arrivals are generally investigated under the scope of the Random Access Channel of LTE, in order to test whether cellular networks will be able to serve such a demand. We approach this problem from a different perspective and propose to separate the medium access scheme for initial arrivals and backlogged users. In order to minimize the access delay, we use tree algorithms to resolve backlogged users. We show with simulations that, by using the feedback that is already included in the random access procedure of LTE, our algorithm achieves lower access delays compared to state of the art solutions. Furthermore, we abstract the algorithm as a multi-channel tree algorithm and discuss limitations and feasible modifications.