Form factor limitations and power constraints in user equipment such as a millimeter wave user equipment lead to link imbalances between uplink beams generated by the user equipment and downlink beams generated by network base stations. For example, the number of antenna elements in a user equipment is typically lower than the number of antenna elements in a base station, which results in an uplink beam range that is smaller than a downlink beam range. The user equipment can therefore detect the base station and nevertheless be unable to establish an uplink connection to the base station, e.g., via a random-access channel (RACH). The effects of the link imbalance are reduced or eliminated by selectively activating different antenna elements at the user equipment and selectively orienting the user equipment based on its antenna configuration relative to the network base station.
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Venkata, Madhu, "Application-Based Beam Selection for Uplink-Downlink Imbalance", Technical Disclosure Commons, (April 09, 2020)