IOT: Wireless connectivity standards & Importance of NB-IOT standard

There are several wireless standards available to support the IOT devices. Most of these standards target to address the following points:

·         Low Power (Long battery life)

·         Low cost

·         Long range communication

·         Indoor connectivity

·         Low data rate

With several standards and platforms being followed by different manufacturers/IOT solution providers, interoperability, Certification & security of the data being exchanged are more important in IOT. If the wireless standards such as Zigbee/Z-Wave/BT/BLE are used for end device connectivity in IOT, then there is always a need for gateway to collect the data from end devices and send it to cloud. The gateway will be capable of providing backend internet connectivity with the help of 2G/3G/4G cellular network.

This leads to have one common underlying standard for connectivity and platform, so that users can have single point access to all their resources/devices and avoid difficulty in understanding of different platforms/devices etc…

·         Zigbee: Wireless protocol based on IEEE 802.15.4 standard. It was developed to support low data rate, low power applications. It operates in 2.4GHz ISM band. There are 3 device types supported: Coordinator, Router, and End Device. Supports a data rate of 250Kbps. Connectivity range (Between 2 devices) is 10meter & can be extended with router and end devices.

·         BLE (Bluetooth Smart): Operates in 2.4GHz ISM Band. Supports data rate of 1Mbps. Connectivity range is 100m.

·         LoRaWAN: Long Range low power Wide Area Network. Operates in ISM band. Proprietary protocol, initially developed by Semtech and now it is part of LoRa alliance. Connectivity range is of 15-20km.

·         6LoWPAN: IPV6 over Low power Wireless Personal Area Network. It is based on underlying IEEE 802.15.4 standard. Supports a data rate of 20-250Kbps.

·         Z-Wave: Wireless protocol developed mainly for Home automation. Operates in ISM band. Data rate supported is 100kbps. Connectivity range is 100meter.

·         ANT+: Defined by ANT+ Alliance & Garmin. Operates in ISM Band. Supports a data rate of 1Mbps.

·         Cellular Network:

o   EC-GSM-IOT

o   LTE-Cat-M1

o   NB-IOT : Part of 3GPP Release 13 and targets to address:

§  Ultra Low cost device

§  Lower power consumption (Improved battery life)

§  Low data rate

§  Support higher number of Low throughput devices 

       Release-13 defines UE category LTE Cat M1 & Cat NB1. Following are the major features:

Features	LTE Cat M1 (eMTc)	LTE Cat NB1 (NB-IOT)
3GPP release	Release 13	Release 13
Uplink Data Rate	1Mbps	250Kbps
Downlink Data Rate	1Mbps	250Kbps
Number of Antenna	1	1
Bandwidth	1.4MHz	180KHz
Data Transmission Mode	Full/Half Duplex	Half Duplex

NB-IOT supports different mode of operation:

·         Stand Alone: To use the GSM carriers

·         In-Band: Utilize the resource blocks within Normal LTE Carrier

·         Guard-Band: Utilize the unused resource blocks in the LTE Guard Band

The design of NB-IOT imposes several challenges, few of them are listed below:

·         Co-existence with LTE

·         Interference

·         Throughput degradation

NB IOT Baseband designers have to optimize the RF front end & support other requirements such as Connected/Idle mode-eDRX to improve the battery life.

With NB-IOT, need of an intermediate gateway might be eliminated and data can be directly synced to the servers. This may emerge as a common connectivity standard for IOT and help in users to control or access their IOT devices over smartphone.