Abstract: In this paper, we propose an adaptive feedback bit allocation strategy for distributed multi-cell pre-coding systems with limited feedback. By analyzing the rate loss of multi-cell joint transmission caused by limited feedback, we provide an approximate upper bound as a function of allocated feedback bit for each
channel. Based on this rate loss, an adaptive feedback bit allocation strategy is proposed. The strategy effectively reduces the rate loss due to limited feedback, and thus significantly increases the system rate. Without additional periodical feedback and heavy computation overhead, the proposed strategy is feasible in real systems. Good performance has been shown in simulation.

Key words: distributed, multi-cell joint transmission, limited feedback, bit allocation