Channel Capacity

October 7, 2022December 9, 2024Antennas, Capacity, Channel Capacity, Fundamentals

Why is MIMO Fading Capacity Higher than AWGN Capacity

From linear algebra we know that to find four unknowns we need four independent equations. There is no way we can find the values of A, B, C and D from the above equations. To simplify the above equations we have removed AWGN but even in presence of AWGN we will have the same predicament. This shows that in the absence of fading there is no multiplexing gain however high the Signal to Noise Ratio is (in the above example SNR is infinite).

July 31, 2011January 30, 2012Channel Capacity, LTE

Average Cell Throughput Calculations for LTE

Average Cell Throughput requires the following simulation results • Average SINR distribution table (system level result), which provides the SINR probability • Average throughput or spectral efficiency versus average SINR table (link level result) For urban channel model and a fixed inter-site distance of 1732m,downlink throughput for LTE for different values of SINR is shown below. MCS vs SINR Average Cell Throughput=Σ(Pi*Ri) where Pi=Probability of occurrence of a specific SINR value at cell edge obtained using simulations Ri=Average throughput corresponding to SINR range Let us consider the following distribution for the SINR at the cell edge: P1=0.5 (SINR=1.50-3.50 dB) P2=0.25 […]

July 6, 2011January 9, 2013Capacity, Channel Capacity, Fundamentals, LTE

Shannon Capacity of LTE (Ideal)

Shannon Capacity of LTE in AWGN can be calculated by using the Shannon Capacity formula: C=B*log2(1+SNR) or C=B*log2(1+P/(B*No)) The signal power P is set at -90dBm, the Noise Power Spectral Density No is set at 4.04e-21 W/Hz (-174dBm/Hz) and the bandwidth is varied from 1.25MHz to 20MHz. It is seen that the capacity increases from about 10Mbps to above 70Mbps as the bandwidth is varied from 1.25MHz to 20MHz (keeping the signal power constant). It must be noted that this is the capacity with a single transmit and single receive antenna (MIMO capacity would obviously be higher).