# Repetition with Learning Approaches in Massive Machine Type Communications
## 2 eMTC System  
eMTC technology involves enhancing and customizing mMTC according to the application requirements, such as repetition, scheduling, discontinuous reception, control channels, and system information block (SIB). The eMTC UE monitors the same master information blocks (MIBs), the scheduling period of which is 40 ms. With eMTC, however, within 40 ms, the MIB information is transmitted at the 0 th, 18 th, and 19 th time slots in each radio frame. As such, the coverage of a physical broadcast channel is enhanced through repetition. In the 3 GPP protocol, eMTC independently defines the SIB information; that is, SIB-BR is composed of SIB1-BR and other numbers of SIB information. SIB-BR features a time-frequency position different from that of LTE. SIB1-BR is transmitted on a physical downlink shared channel (PDSCH) at a fixed period of eight radio frames (80 ms). Within each period, SIB1-BR is repeatedly transmitted 4, 8, or 16 times according to the designation by an MIB. SIB1-BR is transmitted without a controlled schedule through frequency hopping between NBs. The pattern of the frequency hopping is related to the system bandwidths and physical-layer cell identities. The other SIB-BR information is transmitted in the PDSCH; the system information is transmitted without controlled schedules. The schedule information of the system information, such as the time-frequency locations, modulation coding scheme levels, and number of repetitions, is determined in SIB1-BR. When changes occur in the broadcast information, except for SIB10-BR, SIB11-BR, SIB12-BR, and SIB14-BR, an update is announced through paging or DCI6-2 during the period of change, and new broadcast information is transmitted in the subsequent period of change. The same procedure applies when changes occur in SIB10-BR, SIB11-BR, SIB12-BR, and SIB14-BR. Unlike NB-IoT, eMTC supports the switching of connection statuses and uninterrupted service transmission when the UE moves across regions. Therefore, eMTC is applicable for services such as voice calls and logistics tracking. The energy-saving function of eMTC is achieved through extension discontinuous reception, power saving mode, and the reduction in the periodic position update frequency. The 3 GPP system extends the time of the periodic position update procedure to reduce the periodic position update frequency of the UE, thereby mitigating the signal load in the networks and the power expense in the UE. With the power saving mode of the 3 GPP R12 system, the UE timer enters a deep sleep mode after the UE's tracking area is updated and its attach procedure is completed. In the deep sleep mode, the UE does not monitor paging, and the radio transceiver unit is switched off to save significantly more power than that saved in the idle mode. The UE remains registered in the network in the deep sleep mode without the requirement of rerunning the attach procedure or reestablishing the packet data network connection. The physical layer of eMTC is redesigned through 3 GPP, and the eMTC signal coverage is enhanced through the repetition mechanism in the physical channel. In downlink, eMTCemploys neither a physical control format indicator channel nor a physical hybrid automatic repeat request indicator channel. The number of signals transmitted in the 40 ms period is increased in the physical broadcast channel. Rather than the conventional LTE physical downlink control channel, an MTC physical downlink control channel is employed for a maximal repetition number of 256. A maximum of six RBs can be applied by a UE unit in a PDSCH. The modulation coding scheme level and the maximal number of repetitions are restricted; specifically, the maximal number of repetitions is set as 2048. Similarly, a maximum of six RBs can be applied by a UE unit in a physical uplink shared channel (PUSCH). The modulation coding scheme level and the maximal number of repetitions are restricted. In particular, the maximal number of repetitions is set as 2048.