I was reading some releases and other material put out by AT&T recently, and it dawned on me that cellular systems are going to play more of a major role in the IoT movement than I realized. I should have expected that, though, given that AT&T and the other major carriers have been doing IoT in the form of M2M for a decade or more.
Most M2M applications used the 2G and 3G networks for things like remote equipment monitoring and fleet tracking. However, with recent announcements from AT&T and Verizon about shutting down their 2G networks in the near future, I thought maybe M2M/IoT might not be a growth area. Boy, was I wrong. Here is what I’m seeing:
First, market data firmMachina Researchexpects mobile networks to carry 50% of IoT data traffic by 2025. The thing making that possible is the availability of low-cost LTE chips and modules that are ideal for many IoT applications. I am speaking of the low-power, low-speed versions of LTE specified by the 3GPPs Releases 12 and 13.
具体而言，这些被指定为LTE-M（或LTE CAT-M1）和NB-iot。LTE CAT-M1使用通常OFDMA下行链路和SC-FDMA上行链路的最小LTE带宽为1.4 MHz。最大数据速率为1 MB/s。NB-iot仅使用180 kHz的一个LTE资源块（12 ofdm 15 kHz子载波）的带宽。它也使用DMA和SC-FDMA，峰值数据速率为250 kb/s。两者都适合许多物联网应用。
使他们吸引人的是他们的低功耗，这一功能几乎是某些物联网用途的强制性。一些模块最多可用于某些操作的电池寿命10年。然后，范围很大，覆盖范围不超过几公里。而且这种覆盖范围可以像大多数LTE蜂窝细胞一样穿透建筑物，从而使许多室内产品成为可能。
Cellular LTE is going to be competing with several others in the low power wide area network (LPWAN) arena, courtesy of technologies like LoRa, Ingenu, Sigfox, and Weightless. All offer much longer range than the usual Wi-Fi or Bluetooth. These longer range wireless standards use unlicensed spectrum, which makes interference a potential problem. This is less of a problem with cellular and its licensed spectrum, making cellular IoT more reliable—an important factor to consider in a critical application.
另一个认真的考虑是安全。蜂窝网络提供载体级安全性，毫无疑问，比典型的IoT安全措施领先一步。最后，模块的低成本使细胞IoT更具吸引力。现在，对于某些应用程序，值得考虑的蜂窝物联网，模块价格在$ 5到$ 10的范围内，较低的蜂窝物联网值得考虑。
Oh yes: Cellular 5G IoT will also be available in the near future from AT&T and others. If you have applications that require many Mb/s up to 1 Gb/s, 5G is the answer. But you will need to wait until about 2018 or so for that to happen.
在移动应用程序中，细胞IoT擅长的另一个地方。LTE专为便携式和移动使用而设计。因此，LTE Cellular是用于开发高级驾驶员辅助系统（ADA）一部分的无线连接中的主要考虑因素。该系统将实施车辆到车辆（V2V）通信和车辆到基础设施（V2I）连接到路边终端。路边终端还与系统网络对话。
到目前为止,美国交通部(DOT) National Highway Traffic Safety Administration (NHTSA) has proposed that the Dedicated Short Range Communications (DSRC) technology be adopted. DSRC uses the IEEE 802.11p standard that is a variant of Wi-Fi. It uses 10-MHz bands in the 5.9 GHz unlicensed spectrum to achieve a data rate of 10 Mb/s. DSRC V2V radios transmit location, direction, and speed of the vehicle to other vehicles within a 300-meter range. The idea is to provide drivers with better information to prevent accidents. The DOT wants V2V in vehicles within the next few years.
In December, the NHTSA issued a notice of proposed rulemaking (NPRM) mandating DSRC in all light vehicles. Up until recently DSRC was nearly a sure thing until the FCC decided to consider the potential expansion of the 5 GHz Wi-Fi spectrum into the 75 MHz chunk of DSRC’s 5.9 GHz band. Now DSRC supporters are worried that interference from Wi-Fi could make DSRC V2V less effective and reliable. The FCC has not made a decision yet, leaving the issue open.
一个解决方案高通,Intel, AT&T, and others is cellular V2V. The idea is to leapfrog DSRC and go directly to cellular. LTE would be the V2V and V2I links. It will be interesting to see how this evolves. In the meantime, AT&T is joining the American Center for Mobility in the testing of V2x solutions for connected and automated vehicles (CAV). At a 355+ acre test facility in Michigan, the test partners will see how V2x works under real world conditions. AT&T will certainly be trialing LTE and its network for CAV applications. Machina Research expects connected car applications to be 45% of cellular IoT by 2025.
无论如何，寻找比我们许多人想象的要成为物联网更大的一部分。
