CE Mode and CE Level are terms associated with the coverage enhancement techniques in LTE BL/CE, which are designed to support IoT devices in various coverage conditions. These modes and levels dictate how the network and devices behave in terms of power usage, repetition of signals, and the level of enhancement required for the device to maintain a reliable connection.

CE Mode and CE Level:

CE Mode and CE Level are integral to LTE BL/CE, aiming to enhance coverage for IoT devices. These configurations help the device maintain connectivity by adjusting signal repetitions and power usage based on coverage conditions.

CE Mode A:

• No repetition or a small number of repetitions for signal transmission.
• Equivalent coverage to a UE Category 1 device.
• Utilizes LTE-M1's single-receive antenna and reduced bandwidth.
• Operates with lower uplink power, compensating with a smaller number of repetitions.
• Employs legacy LTE power control mechanisms.

CE Mode B:

• Large number of signal repetitions for enhanced coverage.
• Maximized transmission power for PUCCH and PUSCH without TPC field changes.
• Optimized for very poor propagation conditions.

CE Level:

Defines the conditions that determine the operation in either CE Mode A or B, influencing the number of repetitions and the RACH response size.

Mode vs Level vs Preamble Group:

• CE Mode is set by the eNB.
• CE Level is dictated by the network based on signal quality measurements.
• The preamble group is chosen based on CE Level to optimize the RACH procedure.

Understanding these elements is crucial for ensuring the efficient operation of IoT devices across varying network conditions, impacting power consumption, data rate, and connection reliability.

Further Readings

• Operation Mode
• CE Level