Narrowband-IoT (NB-IoT) is a low power wide area network technology introduced by the 3rd Generation Partnership Project (3GPP) in Release 13 specifications. The NB-IoT aims at providing cellular connectivity to low cost, low throughput, delay-tolerant devices, and hence, is a key technology for smart connected living. The NB-IoT specifications continue to evolve as part of 5G New Radio (NR), and the technology is expected to co-exist with 5G NR. A transmission bandwidth of 180 KHz is required to deploy the NB-IoT. In NB-IoT, the duration of the physical downlink control channel (NPDCCH) and the physical downlink shared channel (NPDSCH) changes dynamically. When the base station broadcasts the NPDCCH region, all the active NB-IoT devices try to decode it. Hence, to reduce the power consumption of the NB-IoT devices, more number of NB-IoT devices have to be scheduled in each scheduling attempt. For each payload in NPDCCH, there is a respective payload in NPDSCH. Thus, a base station should schedule the devices simultaneously in both NPDCCH and NPDSCH to reduce resource wastage. The time–frequency resources in NB-IoT are limited and valuable. Further, the NB-IoT devices have low battery power constraint. Thus, scheduling the devices by considering the above constraints has a significant impact on the NB-IoT system performance. Motivated by this, we propose a joint scheduling algorithm for both NPDCCH and NPDSCH. Further, we propose an adaptive repetition allocation algorithm and present a receiver design for NB-IoT. We also define performance metrics to evaluate the impact of the proposed scheduler and then present bounds on the performance gains with the proposed scheduler. With system-level and link-level simulations, we show that the proposed scheduler significantly outperforms the current state-of-the-art algorithms.

窄带物联网（NB-IoT）是第三代合作伙伴计划（3GPP）在版本13规范中引入的低功耗广域网技术。NB-IoT旨在为低成本，低吞吐量，耐延迟的设备提供蜂窝连接，因此是智能连接生活的关键技术。NB-IoT规范作为5G新无线电（NR）的一部分不断发展，该技术有望与5G NR共存。部署NB-IoT需要180 KHz的传输带宽。在NB-IoT中，物理下行链路控制信道（NPDCCH）和物理下行链路共享信道（NPDSCH）的持续时间会动态变化。当基站广播NPDCCH区域时，所有活动的NB-IoT设备都尝试对其进行解码。因此，为了减少NB-IoT设备的功耗，每次调度尝试中必须调度更多数量的NB-IoT设备。对于NPDCCH中的每个有效负载，NPDSCH中都有相应的有效负载。因此，基站应同时在NPDCCH和NPDSCH中调度设备，以减少资源浪费。NB-IoT中的时频资源有限且宝贵。此外，NB-IoT设备具有较低的电池电量约束。因此，通过考虑上述约束来调度设备对NB-IoT系统性能具有重大影响。为此，我们提出了针对NPDCCH和NPDSCH的联合调度算法。此外，我们提出了一种自适应重复分配算法，并提出了一种针对NB-IoT的接收机设计。我们还定义了性能指标以评估建议的计划程序的影响，然后提出建议的计划程序对性能提升的限制。通过系统级和链路级仿真，我们证明了拟议的调度程序明显优于当前的最新算法。