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.
