蜂窩調制解調器利用現(xiàn)有的基礎設施以降低通信開銷

　　在建立機器對機器（M2M）通信的基礎設施時，系統(tǒng)將利用各種無線聯(lián)網(wǎng)方案進行互聯(lián)。然而，為了利用無線網(wǎng)絡標準，如802.11（Wi-Fi）、ZigBee和其他數(shù)據(jù)網(wǎng)絡標準，還必須安裝額外的子系統(tǒng)，如接入點、路由器和其他與網(wǎng)絡相關的硬件。對于設計者來說，使用數(shù)據(jù)網(wǎng)絡在M2M網(wǎng)絡上發(fā)送數(shù)據(jù)是可行的選擇，這就是已經安裝的蜂窩電話網(wǎng)絡。在許多情況下，Wi-Fi或ZigBee等數(shù)據(jù)網(wǎng)絡產品，甚至專有的解決方案可以通過收集來自附近M2M設備的數(shù)據(jù)，然后將其聚合起來，與蜂窩網(wǎng)絡協(xié)同工作。聚合數(shù)據(jù)然后通過蜂窩網(wǎng)絡發(fā)送到中央主機位置。

　　Therefore， rather than install a dedicated， on-all-the-time Ethernet connection that could continuously send data back to the central system， a cellular system can be set to send data on a regular schedule in short or long bursts， depending on the amount of data and the throughput of the cellular connection. Each of the connected devices， vending machines， medical equipment， smart appliances， utility networks， industrial systems， and others could have a cellular modem if they are not in close proximity to each other. When several devices are relatively close， using short-range data networking such as ZigBee， Bluetooth， Wi-Fi， or other wireless interface to send data to a local aggregation point could reduce the hardware costs. Once data is aggregated， a cellular modem can be used to transfer the data to the host system using one of the many cellular standards （GSM， EDGE， HSPA， LTE， and more， Figure 1）。 As costs come down for cellular modems， each device in the field could be fitted with its own modem.