Low data rate LTE - a new approach

The new LTE categories are fullfilling different needs than high speed LTE. Also the application areas differ from what was a "LTE domain". The new LTE category - named Cat. 0 - is covering narrowband  and half duplex operation at reduced data rates.

What is low data rate LTE?

Low data rate LTE is defined by 3 factors:

• low data rate
• low power
• low complexity

These features fit applications that besides low data rate transmit infrequently and are delay tolerant. Therefore this standard idealy supports M2M devices and is referred to as enhancement for Machine Type Communications (MTC).

What do the different Categories mean?

Cat. 1 Rel. 12 is already available in some networks and commercial deployment is expected in 2016. u-blox TOBY-L1 and TOBY-L2 as well as TOBY-R2 and LARA-R2 can work in Cat. 1 networks. Devices operating in a Cat. 1 networks still fullfill the needs of reasonable data rates and VoLTE.

Currently there are two future categories of low data rate LTE: Cat. 0 Rel. 12 and Cat. 0 Rel. 13.
Cat. 0 Rel. 12 is a modified LTE version for M2M communications. Application running on that network can work on a reduced bandwidth and data rate in half duplex operation. It is also possible to have a single receiver antenna so lower computational resources are needed. A power save state allows the device to go into deep sleep and wake up with minimal network signalling. It also features a signalling overhead reduction for more efficient operation when staying connected or infrequent transmission resulting in lower power consumption.

Cat. 0 Rel. 13 is still in a specification phase with 3GPP (3rd Generation Partnership Project), an initiative that unites telecommunications standard development organizations (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC), known as “Organizational Partners” and provides their members with a stable environment to produce the reports and specifications that define 3GPP technologies. For the release 13 an Extended Discontinuous Reception (DRX) in idle and conntected mode is planned. This would enable devices  to go to light sleep for longer and therefore reduce the consumplten when in idle or connected mode.

Feature	Cat. 1	Cat. 0 Rel. 12	Cat. 0 Rel. 13
UE RF Bandwidth	20 MHz	20 MHz	1.4 MHz
DL Peak Rate	10 Mbps	1 Mbps	~ 200 kbps
Max. no. of DL layers	1	1	1
UL Peak Rate	5 Mbps	1 Mbps	~ 200 kbps
No. of RF Rx chains	2	1	1
Max. UE Tx power	23 dBm	23 dBm	~ 20 dBm
Duplex Mode	Full	Half and full duplex	Half and full duplex

 

So future applications using LTE Cat. 0 Rel. 13 benefit of the following features:

• low data rate
• transmit infrequently
• delay tolerant
• low(er) power
• low(er) cost