Refer to the link and info below for more detail.
The important point to take away from this is that the MIX OBC uses CAT M1 for the LTE modems.
This means that the speed of CAT M1 (375 Kbps) is slightly higher than 2G (250 Kbps) but much slower than 3G (up to 3Mbps)
http://support.huawei.com/huaweiconnect/carrier/en/thread-360433-1-1.html
1G – The analog 1G offered simple telephony service without data.
2G – Delivered digital signal and offered up to 250Kbps speed. Supports voice, text and data services.
3G – At least 200Kbps up to 3Mbps speed.
4G – 4G delivers up to 100Mbps for mobile access, and up to 1Gbps for wireless access. Most wireless carriers offering HSPA (High Speed Packet Access) at up to 6Mbps are claiming that they offer 4G network.
4G LTE – LTE (Long Term Evolution) is one of the two standards offered within 4G, and WiMax being the second one. The specification calls for downlink speed of up to 300Mbps and uplink speed of up to 75Mbps.
CAT M1 – 375 Kbps