Transmit power is controlled for a first uplink data transmission on
Physical Uplink Shared Channel (PUSCH) during random access channel
(RACH) procedure. Power control adjustment for the first PUSCH
transmission is performed relative to the power spectral density used for
successful PRACH transmission as adjusted for bandwidth difference, etc.
The uplink Physical random access channel carries the RACH information
that is transmitted by the user equipment (UE) during registrations or
base station originated calls. A PRACH is composed of a number of
preambles and a message portion. The preambles are a series of radio
frequency power "steps" that increase in power according to the power
step setting until the maximum number of preambles is reached or the base
station acknowledges. Once the UE receives a positive indication, it
transmits the message portion of the PRACH which consists of message data
and control data with independent power gain control.