STR vs. EMLMR
Both STR (Simultaneous Transmit and Receive) and EMLMR (Enhanced Multi-Link Multi-Radio) are advanced Wi-Fi 7 features that enable multi-link operation (MLO). However, they differ in hardware requirements, performance, and use cases. Below is a detailed comparison.
Key Differences at a Glance:
| Feature | STR (Simultaneous Tx/Rx) | EMLMR (Multi-Radio MLO) |
| Definition | Tx on one band + Rx on another band at the same time | Simultaneous operation on multiple links (but not necessarily Tx+Rx at the same time) |
| Hardware Requirement | Dedicated radios per band with strong RF isolation | Multiple radios (but no strict Tx+Rx concurrency) |
| Latency | Ultra-low (~1–5ms) (near full-duplex) | Low (~5–10ms) (better than EMLSR but not as good as STR) |
| Throughput | Highest (no Tx/Rx contention) | High (but may have minor contention) |
| Power Consumption | Very High (active Tx+Rx) | High (multiple radios) |
| Cost | Very Expensive (complex RF design) | Expensive (but cheaper than STR) |
| Best For | Industrial IoT, metaverse, surgical robotics | Gaming, 8K streaming, enterprise APs |
1. How STR Works?
- True Simultaneous Tx/Rx:
- A device can transmit (Tx) on 5GHz while receiving (Rx) on 6GHz at the exact same time.
- Requires advanced RF isolation to avoid self-interference.
- Example:
- A cloud gaming PC sends controller inputs (5GHz Tx) while receiving the game stream (6GHz Rx) without any delay.
2. How EMLMR Works?
- Simultaneous Multi-Link (but not necessarily Tx+Rx at the same time):
- A device uses multiple radios to operate on different bands independently.
- Example:
- Downloading a file on 6GHz while uploading a video on 5GHz (but not necessarily at the exact same nanosecond).
Performance Comparison:
1. Latency
| Technology | Latency | Why? |
| STR | ~1–5ms | No switching delays, true Tx+Rx concurrency. |
| EMLMR | ~5–10ms | Slight scheduling delays between links. |
| EMLSR | ~15–30ms | Single-radio switching adds overhead. |
2. Throughput
| Technology | Throughput | Why? |
| STR | Highest (10+ Gbps) | No Tx/Rx contention. |
| EMLMR | High (5–8 Gbps) | Minor contention possible. |
| EMLSR | Medium (2–4 Gbps) | Switching reduces efficiency. |
3. Power Efficiency
| Technology | Power Use | Why? |
| STR | Very High | Both radios active (Tx+Rx). |
| EMLMR | High | Multiple radios but not always Tx+Rx. |
| EMLSR | Low | Only one radio active at a time. |
Which One Should You Use?
✅ Use STR If:
- You need ultra-low latency (e.g., surgical robots, cloud gaming).
- You have high-end hardware (e.g., enterprise APs, Wi-Fi 7 routers like ASUS ROG Rapture GT-BE98).
- Cost and power are not concerns.
✅ Use EMLMR If:
- You want high performance but don’t need true full-duplex.
- You’re using gaming laptops, AR/VR headsets, or high-end smartphones.
- You need a balance between cost and performance.
❌ Avoid Both If:
- You’re using budget devices (stick with EMLSR).
- Battery life is critical (e.g., smartphones, IoT).
Future of STR & EMLMR:
- Wi-Fi 7 (2024–2025): EMLMR dominates (due to cost), STR remains niche (industrial/medical).
- Wi-Fi 8 (802.11bn): May introduce true full-duplex STR (zero latency).
Final Verdict:
| Feature | STR | EMLMR |
| Performance | 🚀 Best | ⚡ Great |
| Latency | 1–5ms | 5–10ms |
| Cost | $$$$ | $$$ |
| Power Use | 🔋💀 | 🔋🔋 |
For most users, EMLMR is the best balance. For mission-critical apps, STR is unmatched.