the small cell is mainly used for providing more coverage instead of high capacity or high peak rates. If multiple small cells share the same transport, then the total transport rate can be less than the sum of the peak rates because different cells are not typically fully loaded at the same time. That benefit is called trunking gain. The fronthaul requirement with CPRI is over 4 Gbps with 20 + 20 MHz and 2x2 MIMO and increases a function of the bandwidth and the number of antennas. The data rate is independent of the cell loading or throughput requirements. The throughput requirement can be lowered by using CPRI compression but it comes at the expense of signal RF quality leading some of degradation of Error Vector Magnitude (EVM). We will next illustrate how the fronthaul requirement increases as a function of bandwidth and antenna lines with OBSAI interface. The OBSAI line rate needs to be in multiples of 768 Mbps, which means 768, 1536, 3072 and 6144 Mbps. The master frame size in bytes is i*N_MG*(M_MG*19+K_MG) where i = 1, 2, 4, 8 that means multiples of 768 line rate. The master frame illustrating the sequence according to which LTE messages are inserted to the bus (parameter set M_MG = 21, N_MG = 1920, K_MG = 1, i = 1). We take into account that the sampling rate for 20 MHz LTE is 30.72 MHz and for OBSAI I and Q samples are mapped into 16 bits each. Single antenna 20 MHz stream requires 0.98304 Gbps. The corresponding OBSAI stream is using i*N_MG*(M_MG*19+K_MG) and the parameters above give 1.032192 Gbps. As the line rate for OBSAI is 768 Mbps this requires 1.536 Gbps OBSAI. The needed data rate for 2x2 MIMO with 20 MHz is 1.96608 Gbps, OBSAI frame rate 2.064384 Gbps and needed OBSAI interface 3.072 Gbps. The required fronthaul data rate grows with larger bandwidth in carrier aggregation and with more antennas. If we have 20 + 20 MHz carrier aggregation with four-antenna base station, the required frame rate is approximately 8 Gbps. A comparison of backhaul and fronthaul requirements is presented in Table 