NB - IoT 하향 링크 에 는 NPBCH ( Narrowband Physical Broadcast Channel ) , NPDSCH ( Narrowband Physical Downlink Shared Channel ) , NPDCCH ( Narrowband Physical Downlink Control Channel ) 와 같 은 물리 채널 이 제공 되 며 , NPSS ( Narrowband Primary Synchronization Signal ) , NSSS ( Narrowband Primary Synchronization Signal ) , NRS ( Narrowband Reference Signal ) 와 같 은 물리 신호 가 제공 된다 .