Distributed Queuing-based Random Access Procedure in Mobile Networks

Random access procedure is an access mechanism to radio resources in Long Term Evolution (LTE) mobile networks to handle a competition for radio resources of Machine Type Communication (MTC) devices. In the random access procedure, the MTC devices transmit a request for radio resources in the first available opportunity. The devices which select the same resource fail the access and need to compete again. Thus, in the case that massive number of MTC devices are competing at the same time and transmit the access request simultaneously, the system performance may degrade for the high collision probability. Thus, a challenge is to develop a solution ensuring low collision probability for massive number of MTC devices while guaranteeing fairness. A suitable extension of a conventional random access procedure towards support of massive MTC access is to distribute colliding devices into parallel queues. This approach is known as Distributed Queueing Random Access Procedure (DQRAP). The DQRAP improves the performance regardless of the number of MTC devices and thus enables massive MTC communication. This thesis aims to development of analytical models to estimate the performance of the average maximum access delay and the average number of transmissions in a multi-channel slotted ALOHA system using DQRAP. As the results of a numerical analysis and simulations show, the proposed models accurately approximate the simulations.