Calculate 4G LTE spectral efficiency in bits/s/Hz from modulation, code rate, MIMO layers, and channel overhead.
effective spectral efficiency (bits/s/Hz)
Modulation order (Qm)
Code rate (R)
MIMO layers
Raw SE (no overhead)
Effective SE (with overhead)
Shannon capacity (bits/s/Hz)
Efficiency vs Shannon
Peak LTE Cat 4 SE (reference)~8.3 bits/s/Hz
Peak LTE spectral efficiency (Cat 4): 64QAM, 2 MIMO layers, 25% overhead → ~8.3 bits/s/Hz. LTE-A Pro with 256QAM and 4 layers can reach ~22 bits/s/Hz. 5G NR exceeds this with up to 8 layers and lower overhead (~14%).
Frequently Asked Questions
What is LTE spectral efficiency?
LTE spectral efficiency measures how much data can be transmitted per unit of bandwidth, expressed in bits per second per hertz (bits/s/Hz). It depends on the modulation scheme (QPSK, 16QAM, 64QAM, or 256QAM in LTE-A Pro), the code rate, the number of MIMO spatial layers, and the proportion of the channel used for overhead. The formula is: SE = Qm × R × layers × (1 − overhead%).
How does LTE compare to 5G NR in spectral efficiency?
5G NR achieves higher spectral efficiency than LTE for several reasons: it supports up to 8 MIMO layers (4 is typical in LTE), has lower overhead (around 14% vs 25% for LTE), and uses more advanced LDPC codes instead of turbo codes. Peak LTE spectral efficiency with 64QAM and 2 layers is about 8.3 bits/s/Hz, while 5G NR with 256QAM and 8 layers can reach over 51 bits/s/Hz.
What is the peak LTE spectral efficiency?
Peak LTE (Category 4) spectral efficiency with 64QAM and 2 MIMO layers is approximately 8.3 bits/s/Hz. LTE-Advanced Pro with 256QAM and 4 MIMO layers can reach approximately 22 bits/s/Hz on a single carrier. LTE-A with carrier aggregation multiplies throughput by combining carriers but does not change per-carrier spectral efficiency.