RESEARCH OF RANDOM ACCESS PROCEDURE ON MACHINE TYPE COMMUNICATION

Machine Type Communication (MTC) is machine to machine communications in cellular network. It plays the key role for intelligent services and there is a great market prospect for these services. Comparing with H2H communications, there are significant changes in service features. In 3GPP Release-13, there are three objectives of enhancement for MTC, including UE complexity reduction, coverage enhancement and UE power consumption reduction. The supported RF bandwidth has been agreed as 1.4MEZ and repetition technique for channels is considered to achieve coverage improvement. However, due to these improvement, if the conventional method continues to be used, the collision probability of PRACH transmission and the power consumption of MTC UEs will be higher than the legacy UEs. In order to alleviate this issue, this paper concentrates on the random access procedure on low cost MTC and it takes the coverage enhancement level into the consideration which isn't the dimension of legacy LTE system. It proposes a method about new mapping relationship between PRACH resource set and coverage enhancement level. By this way, it can reduce the collision probability and improve the utilization of radio resources, which consequently increases the success probability of random access and reduces the power consumption. Finally, the simulation result shows that the method can improve the performance of low cost MTC.