Cellular Network Infrastructure » Radio Access Network » OsmoPCU

EC-GSM-IoT is a GERAN extension introduced in 3GPP Release 13, aimed at enabling long-range, low-power IoT devices on top of GSM/GPRS/EDGE.

The feature was originally called EC-EGPRS (extended coverage Enhanced GPRS), and only later renamed for marketing reasons.

At the very least, it consists of very significant extensions to the RLC/MAC layer by introducing EC-BCCH, EC-PCH, EC-RACH, EC-AGCH, EC-PACCH, EC-GPRS-TBF

Further Reading:

• http://www.3gpp.org/ftp/workshop/2015-11-15_Taipei_summit_5G/Docs/2_5_2015_ITRI_3GPP_summit_GERANv05.pdf
• http://www.3gpp.org/news-events/3gpp-news/1766-iot_progress
• https://code.wireshark.org/review/#/c/15812/
• M2M_20140630.doc from http://www.3gpp.org/ftp/Information/WORK_PLAN/Description_Releases/M2M_20140630.zip
• http://www.3gpp.org/DynaReport/GanttChart-Level-2.htm#bm690006
• http://www.3gpp.org/DynaReport/WiCr--690006.htm
• 24.008: Update of NAS timers for EC-GSM: http://www.3gpp.org/ftp/tsg_ct/TSG_CT/TSGC_72_Busan/Docs/CP-160318.zip
• EC-EGPRS Multislot: http://www.3gpp.org/ftp/tsg_geran/TSG_GERAN/GERAN_68_Anaheim/Docs/GP-151197.zip
• http://www.3gpp.org/ftp/tsg_geran/TSG_GERAN/GERAN_68_Anaheim/Docs/GP-151212.zip
• 43.064: GP-151212 CR43064 Introduction of Power Efficient Operation and EC-EGPRS, Radio interface (revision of GP-151154).docx of http://www.3gpp.org/ftp/tsg_geran/TSG_GERAN/GERAN_68_Anaheim/Docs/GP-151212.zip
• 45.003: GP-151180 CR 45.003-0135 rev 2 Introduction of EC-EGPRS (revision of GP-151099).doc of http://www.3gpp.org/ftp/tsg_geran/TSG_GERAN/GERAN_68_Anaheim/Docs/GP-151180.zip

After a very brief review, it seems that at the very least

• new convolutional coding schemes are introduced for messages in a single burst (rather than the usual 4)
• 'blind retransmissions' are introduced to re-transmit messages up to 28 times
• new logical channels are introduced

i.e. changes to physical layer and RLC/MAC are required.