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This section explains the theory, assumptions, 3GPP references, formulas and logic used inside the 5G NR Throughput Calculator.

1. What Determines 5G NR Throughput?

The throughput in 5G NR fundamentally depends on:

• Allocated PRBs (N_PRB)
• Modulation Order (Qm)
• Coding Rate (R)
• Number of Layers (ν)
• Resource Elements (REs) per PRB
• Slots per second (depends on numerology μ)
• DL Duty Cycle (TDD only)
• Number of Component Carriers (CA)
• Overheads: DM‑RS, PDCCH, CSI‑RS, SSB etc.

These relationships come from 3GPP:

• MCS Tables → Qm, R come from 3GPP TS 38.214 §5.1.3.1
• TBS / RE calculation → Defined in 3GPP TS 38.214 (TBS calculation)
• Slot duration & slots/sec → Defined by NR numerology in 3GPP TS 38.211 (frame/slot structure)
• Peak throughput formula → Referenced in 3GPP TS 38.306 (UE capability)

2. NR Numerology (μ) → Slots per Second

5G NR uses flexible numerology μ, where each step doubles the subcarrier spacing and halves slot duration.

According to 3GPP NR numerology rules:

• Slot duration = 1 ms / 2^μ
• Slots per 10 ms frame = 10 × 2^μ
• Slots per second = 1000 × 2^μ

Reference: 14 symbols/slot for Normal CP and slot duration scaling appear in 3GPP numerology descriptions.

Used in calculator formula:

SlotsPerSecond = 1000 × 2^μ

3. MCS → Modulation Order (Qm) + Code Rate (R)

The calculator implements MCS Tables 1, 2, and 3 from:
3GPP TS 38.214, Table 5.1.3.1‑1, 5.1.3.1‑2, 5.1.3.1‑3.

Each entry gives:

• Qm: bits per symbol → (QPSK=2, 16QAM=4, 64QAM=6, 256QAM=8)
• R: Target code rate = (value / 1024)

Example (from Table 1):
MCS 18 → Qm = 6, R = 466/1024

The plugin loads these values exactly and uses them in throughput formulas.

4. Resource Elements (RE) per PRB

Each PRB has 12 subcarriers × (# data symbols).

Since every slot has 14 OFDM symbols (Normal CP) (3GPP NR numerology):

N_RE' = 12 × (DataSymbolsPerSlot)

But DM‑RS and overhead must be removed. Using 38.214 logic:

N_RE = min(156, N_RE' – DMRS – Overhead)

The calculator uses the cap 156 RE/PRB, documented in open TBS calculations based on 3GPP rules.

5. Information Bits (Ninfo) and TBS Calculation (TS 38.214)

The transport block size (TBS) is based on the total number of REs across all PRBs:

N_RE_total = N_RE × N_PRB

Information bits:

Ninfo = N_RE_total × Qm × R × ν

The TBS algorithm in 3GPP TS 38.214 splits into two cases depending on Ninfo ≤ 3824 or > 3824. The calculator uses the standard engineering rounding:

TBS = 6 × floor(Ninfo / 6)

This rounding to 6‑bit multiples is also described in TBS computation workflows.

6. TBS-Based Throughput Formula (Per CC)

Once TBS/slot is known, the reachable throughput for one component carrier is:

Throughput_per_CC (bps) = TBS × SlotsPerSecond × DL_DutyCycle

DL duty cycle is applied only for TDD mode. Duty cycle logic comes from standard understanding of TDD dynamic DL/UL allocation.

Output shown in Mbps:

Throughput_Mbps = (TBS × SlotsPerSecond × DL_DutyCycle) / 1e6

7. Peak Throughput Formula (38.306‑Style)

3GPP TS 38.306 defines a UE maximum data rate depending on:

• PRBs allocated
• 12 subcarriers per PRB
• Qm
• R (often Rmax = 948/1024 at highest MCS)
• ν layers
• symbols/slot
• slots per second
• overhead factor

Engineers often summarize the relationship as:

BitsPerSlot = (PRB × (12 × DataSymbols) × Qm × R × ν × (1 – OH))

Then:

Throughput_per_CC_Mbps
= BitsPerSlot × SlotsPerSecond × DL_DutyCycle / 1e6

This aligns with the peak data-rate logic found in NR UE capability explanations.

8. Component Carrier Aggregation (CA)

Final throughput is the sum across all carriers:

Total_Throughput = Throughput_per_CC × J

Where J = number of aggregated carriers (up to 16 as per NR CA discussions).

 9. Summary Table of All Formulas Used