Category: LTE

A 4G technology that is now being replaced by 5G worldwide.

Channel 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 […]

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Capacity, LTE

LTE Data Rate Calculation

Peak LTE data rate can be calculated using the following parameters: 1 Time-slot=0.5 ms (i.e 1 Sub-frame = 1 ms) 1 Time-slot=7 Modulation Symbols (when normal CP length is used) 1 Modulation Symbol=6 bits; if 64 QAM is used as modulation scheme Data rate for a single carrier=Number of symbols per time slot*Bits per symbol/Duration of a time slot=7*6/0.5e-3=84kbps If 1200 carriers (100RBs) are used then the aggregated throughput would be=1200*84kbps=100.8Mbps If 4×4 MIMO is used then the capacity would increase four fold to=403.2Mbps With 3/4 channel coding the data rate would be reduced to=302.4Mbps Note: 1. A Resource Block […]

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Capacity, LTE

Shannon Capacity of LTE (Effective)

In the previous post we calculated the Shannon Capacity of LTE as a function of bandwidth. We now calculate the capacity as a function of SNR (bandwidth fixed at 20MHz and signal power varied). We also use the concept of effective bandwidth to get a more realistic estimate of the capacity. The modified Shannon Capacity formula is given as: C=B_eff*log2(1+SNR) where B_eff=Bandwidth*eff1*eff2*eff3*eff4 eff1=0.9=due to adjacent channel leakage ratio and practical filter issues eff2=0.93=due to cyclic prefix eff3=0.94=due to pilot assisted channel estimation eff4=0.715=due to signalling overhead B_eff=0.57*B Therefore C=0.57*B*log2(1+SNR) Note: This is the capacity in a SISO channel with no […]

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Capacity, 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).  

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