Feedback Overhead in the FDD Downlink Massive MIMO System

Table 11

Compression rate of LZW and LZWM algorithms in different MMIMO-OFDM configurations. , , and , respectively, stand for the number of antennas at the BS, the number of antennas at each UE, the number of UEs, and the number of OFDM subcarriers.

MMIMO-OFDM	Feedback amount without compression in bits	Feedback amount with GR & LZW in bits	Compression rate	Feedback amount with GR & LZWM in bits	Compression rate
	524288	35664	93.20%	7373 98.59%
	1048576	55224	94.73%	10878	98.96%
	2097152	78611	96.25%	15817	99.24%
	1048576	90051	91.42%	27282	97.39%
	2097152	138628	93.38%	39870	98.09%
	4194304	197288	95.29%	58895	98.59%
	4194304	296805	92.92%	58895	98.59%
	8388608	422475	94.96%	86182	98.97%
	16777216	640704	96.18%	126957	99.24%