Contention Based Access for Machine-Type Communications over LTE

To enable the efficient and low latency machine-type communications (MTC) over long term evolution (LTE), a contention based access (CBA) method is proposed. With CBA, UEs transmit packets on the randomly selected resource without having any UE specific scheduled resources. To address the problem of collision caused by CBA in high traffic load, eNB exploits the MU-MIMO detection technique to decode radio network temporary identifier (RNTI) of the collided UEs and use this information to perform a regular scheduling in subsequent subframe. Detailed low layer signaling enhancement to implement CBA technique in current LTE specification (Rel. 10) is also presented. Simulation results demonstrate that the CBA significanlty outperforms the existing uplink channel access methods.