head. Channel estimation and receiver types are the factors that affect the demodulation performance. The availability of CSI at the eNB is the assumption that impacts the transmit signal processing at the eNB for MU-MIMO and CoMP schemes. In the tables for the uplink, the PUCCH bandwidth is the factor that affects the overhead. Each value in Table 12-18 and Table 12- 19 is obtained as an average of all the samples provided by different companies. The results suggest that the requirements are fulfilled with L = 3 corresponding to the largest overhead, except for the system bandwidth of 1.4 MHz where the requirements cannot be met. If the control overhead assumption is relaxed, that is the number of active users decreases, L = 1 and 2 can be considered and thereby the performance can be further improved. The tables show that the 3GPP LTE Rel-8 with SU- MIMO 4 X 2 can already fulfill the ITU-R requirements. The tables also show that further performance improvements can be achieved by using additional technical features. In the following tables, various antenna configurations have been utilized. There are four or eight transmit antennas with the following configurations: (1) uncorrelated co-polarized, i.e., co-polarized antennas that are 4-wavelengths apart; (2) grouped co-polarized, i.e., two groups of co-polarized antennas where there is a 10-wavelength distance between the center of each group and a 0.5- TABLE 12-18 3GPP LTE-Advanced Downlink Cell and Cell-edge Spectral Efficiencies [13] ITU-R Requirement Cell Spectral Efficiency (bits/ Cell-edge Spectral Efficiency Cell Spectral s/Hz/cell) (bits/s/Hz) Scheme and Antenna Duplex Efficiency/Cell-edge Environment Scheme Spectral Efficiency Configuration Rel-8 SU-MIMO 3/0.1 4 X 2 (A) MU-MIMO 4 X 2 (C) 3/0.1 Rel-8 SU-MIMO 3/0.1 4 X 2 (A) MU-MIMO 4 X 2 (C) 3/0.1 MU-MIMO 4 X 2 (C) 2.6/0.075 0.096 0.087 0.099 MU-MIMO 4 X 2 (A) 2.6/0.075 CS/CB-CoMP 4 X 2 (C) 2.6/0.075 0.099 0.089 JP-CoMP 4 X 2 (C) 2.6/0.075 MU-MIMO 8 X 2 (C/E) 2.6/0.075 2.6/0.075 0.096 0.089 MU-MIMO 4 X 2