4G LTE vs 5G NR Resource Allocation
Interactive 3D Visualization of Time & Frequency Domain Resource Mapping
🎛️ Visualization Controls
Data Channel (PDSCH/PUSCH)
Control Channel (PDCCH)
Reference Signals (DMRS/PTRS)
Synchronization (PSS/SSS)
Guard Band / Unused
📡 4G LTE Resource Grid
Release 8-15
Live Animation
Subcarrier Spacing
15 kHz (Fixed)
Slot Duration
0.5 ms
Symbols/Slot
7 (Normal CP)
🚀 5G NR Resource Grid
Release 15+
μ=1 | 30 kHz SCS
Subcarrier Spacing
30 kHz
Slot Duration
0.5 ms
Slots/Subframe
2
📊 Detailed Parameter Comparison
| Parameter | 4G LTE | 5G NR (μ=1) | Key Difference |
|---|---|---|---|
| Subcarrier Spacing | 15 kHz (fixed) | 30 kHz | NR supports multiple numerologies (15, 30, 60, 120, 240 kHz) |
| OFDM Symbol Duration | 66.67 μs | 33.33 μs | Shorter symbols enable lower latency |
| Cyclic Prefix (Normal) | 4.69 μs | 2.34 μs | Scaled with numerology |
| Slot Duration | 0.5 ms (fixed) | 0.5 ms | NR slot duration = 1ms / 2^μ |
| Symbols per Slot | 7 (Normal CP) | 14 (Normal CP) | NR always has 14 symbols/slot |
| Slots per Subframe | 2 (fixed) | 2 | NR: 2^μ slots per 1ms subframe |
| Slots per Frame | 20 | 20 | NR: 10 × 2^μ slots per 10ms frame |
| Resource Block (RB) | 12 subcarriers × 7 symbols | 12 subcarriers × 14 symbols | NR RB spans full slot (14 symbols) |
| RB Bandwidth | 180 kHz | 360 kHz | Scales with SCS: 12 × SCS |
| Max Bandwidth | 20 MHz | 100 MHz (FR1) / 400 MHz (FR2) | 5G supports much wider bandwidth |
| Scheduling Flexibility | Subframe-based (1ms) | Slot/Mini-slot based | NR allows symbol-level scheduling |
📚 Understanding Resource Allocation
📡 4G LTE Resource Structure
- Fixed Numerology: Only 15 kHz subcarrier spacing
- Resource Element (RE): 1 subcarrier × 1 OFDM symbol
- Resource Block (RB): 12 subcarriers × 7 symbols = 84 REs
- Subframe: 1ms duration, contains 2 slots
- Frame: 10ms, contains 10 subframes (20 slots)
- TTI (Transmission Time Interval): 1ms minimum
- Control Region: First 1-3 OFDM symbols (PDCCH)
- Reference Signals: Cell-specific RS scattered pattern
🚀 5G NR Resource Structure
- Flexible Numerology: μ=0 to μ=4 (15 to 240 kHz SCS)
- Resource Element (RE): 1 subcarrier × 1 OFDM symbol
- Resource Block (RB): 12 subcarriers × 14 symbols = 168 REs
- Slot: Duration = 1ms / 2^μ (scales with numerology)
- Mini-slot: 2, 4, or 7 symbols for URLLC
- Frame: 10ms, contains 10 × 2^μ slots
- CORESET: Configurable control region (flexible location)
- Reference Signals: UE-specific DMRS, more efficient
💡 Key Insights
Why 5G Has Flexible Numerology?
Different use cases require different trade-offs between latency and coverage. Higher SCS = shorter symbols = lower latency but higher phase noise sensitivity. Lower SCS = better for high mobility and coverage.
Time-Frequency Duality
Doubling the subcarrier spacing halves the symbol duration. This maintains the same spectral efficiency but enables faster scheduling and lower latency applications.
Resource Efficiency
5G NR uses UE-specific reference signals instead of cell-specific, reducing overhead and improving spectral efficiency, especially for massive MIMO scenarios.