4-Tx Uplink Codebook

Technical Explanation

Modern high-end 5G handsets incorporate 4 transmitter chains (4-Tx) to boost uplink throughput. However, user hand grip and thermal variations cause severe power imbalances and phase shifts across antennas. Rel-18 enhances 4-Tx codebooks with asymmetric power allocation and partial-coherent subsets, maximizing radiated uplink power without distortion.

Key Functions

• Optimizes precoding matrices for 4-Tx user equipment with unequal power amplifiers
• Accommodates antenna detuning and hand-grip blockage common on handheld smartphones
• Supports coherent, partial-coherent, and non-coherent terminal transmission modes
• Boosts peak uplink data rates up to 4x4 MIMO on commercial handset form-factors