CPC H04W 72/23 (2023.01) [H04L 1/1864 (2013.01); H04L 1/1896 (2013.01); H04L 5/0053 (2013.01); H04W 52/02 (2013.01); H04W 72/04 (2013.01); H04L 5/0055 (2013.01); Y02D 30/70 (2020.08)] | 12 Claims |
1. A method performed by a narrow band internet of things (NB-IoT) user equipment (UE), the method comprising:
receiving, from a base station, a radio resource control (RRC) message including configuration information associated with a plurality of enhanced coverage levels, wherein the configuration information associated with the plurality of enhanced coverage levels includes:
information on an initial power of a random access preamble for a first enhanced coverage level,
information associated with a power ramping for the first enhanced coverage level,
information on an initial power of a random access preamble for a second enhanced coverage level, and
information associated with a power ramping for the second enhanced coverage level;
identifying the UE belongs to the first enhanced coverage level based on a reference signal received power (RSRP);
identifying a first transmit power, determined by the information on the initial power of the random access preamble for the first enhanced coverage level;
performing a first random access preamble transmission based on the first transmit power;
performing retransmissions using the information associated with the power ramping for the first enhanced coverage level, used for the first enhanced coverage level of the UE in case that a random access response corresponding to the first random access preamble transmission is not received;
in case that the first random access preamble transmission is not successful by the retransmission, continue performing, by the UE, preamble transmission attempts based on the information associated with the power ramping for the first enhanced coverage level in case that a maximum number of preamble transmission attempt is not reached in the first enhanced coverage level; and
in case that the maximum number of preamble transmission attempt is reached in the first enhanced coverage level,
selecting a resource corresponding to a second enhanced coverage, used for a second random access preamble transmission,
identifying a second transmit power, determined by the initial power of the random access preamble for the second enhanced coverage level,
performing the second random access preamble transmission based on the second transmit power, and
performing retransmissions using the information associated with the power ramping for the second enhanced coverage level, used for the second enhanced coverage level of the UE in case that a random access response corresponding to the second random access preamble transmission is not received,
wherein the first enhanced coverage level is different from the second enhanced coverage level.
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