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1.4.3 Comparative Study of Wireless Standards for Industrial IoT
ОглавлениеAs noted already, various wireless technologies and standards provide connectivity in industrial systems. To choose the appropriate wireless technology for an industrial IoT application, different factors should be considered. Tables 1.1 and 1.2 present the main technical differences among the aforementioned technologies. The comparison considers the PHY and MAC layer features along with various performance measures that each technology aims to fulfill. Such comparative study would assist in specifying potential wireless technologies for an industrial application.
Table 1.1 Comparison of Wireless Technologies: Short-Range Technologies.
| Zigbee | Wireless HART | ISAlOO.lla | WIA-PA | BLE | Wi-Fi HaLow | |
|---|---|---|---|---|---|---|
| Standard | IEEE 802.15.4 | PHY: IEEE 802.15.4 MAC: HART | IEEE 802.15.4 | IEEE 802.15.4 | IEEE 802.15.1 | IEEE 802.11.ah |
| Frequency band | 2.4 GHz | 2.4 GHz | 2.4 GHz | 2.4 GHz | 2.4 GHz | Sub-lGHz |
| Number of | 16 | 16 | 16 | 16 | 405 | 76 |
| Channels | ||||||
| Topology | Star, Tree, Mesh | Star, Mesh | Star, Mesh, Star-Mesh | Hybrid Star-Mesh | P2P, Star, Mesh7 | Star, Tree |
| Spreading | DSSS | DSSS, FHSS | DSSS, FHSS | DSSS | FHSS | MIMO-OFDM |
| MAC channel access | GTS, CSMA; Time slot is flexible | TSMP (TDMA, CSMA); Time slot of 10 ms | TDMA, CSMA; Time slot of 10–12 ms | TDMA, CSMA and FDMA; Time slot is configurable | TDMA | Hybrid EDCA/DCF |
| Channel bandwidth | 2 MHz | 2 MHz | 2 MHz | 20 MHz | 2 MHz8 | l/2/4/8/16 MHz |
| Range | 10–100 m | <600 m | <600 m (100 m9) | l–100 m | <100 m (<300 m7) | 90 m-l km |
| Data rate | <250 Kbps | <250 Kbps | <250 Kbps | <250 Kbps | < 1 Mbps (0.125/ l/2 Mbps7) | 0.15-78Mbps10 |
| Nodes per network | 64,000 | Hundreds per AP | Thousands per gateway | 100 | Piconet: 7 | 8192 |
| Power profile | ~ 3 years | 4–10 years | 6 years | 1 year | 1 year | ~1.5–13 years |
| Latency | Enumeration 30 ms | >10 ms | > 100 ms | >10 ms | >6 ms | >5 ms |
| Encryption | 128-bit AES | 128-bit AES | 128-bit AES | 128-bit AES | 128-bit AES | WPA |
Table 1.2 Comparison of Wireless Technologies: Long-Range Technologies.
| NB-IoT | LTE-M | LoRa/LoRaWAN | |
|---|---|---|---|
| Standard | 3GPP Rel.13 (planned) | 3GPP Rel.13 (planned) | LoRa-Alliance (De-facto Standard) |
| Frequency band | Licensed LTE band | Licensed LTE band | Unlicensed sub-GHz11 |
| Modulation | LTE-based OFDMA(DL) & SC-FDMA(UL) | LTE-based OFDMA(DL) & SC-FDMA(UL) | Proprietary CSS |
| Spreading | FDD/TDD | FDD | FHSS(ALOHA) |
| bidirectional | Yes/Half-duplex | Yes/Half-duplex | Yes/Half-duplex |
| Maximum payload length | 256 bytes | 1600 bytes | 243 bytes |
| Maximum coupling loss (MCL) | 155.7 dB | 165 dB | 169 dB |
| Channel bandwidth | 1.4–20 MHz | 180/200 KHz | 125/250/500 KHz |
| Data rate | DL: 300 Kbps; UL: 375 Kbps12 | DL: 200–300 Kbps; UL: 144 Kbps | 22 bps–50 Kbps13 |
| Range | 11 Km | 1 Km(urban), 11 Km(rural) | 2 Km(urban),15 Km(rural) |
| Latency | 10 ms–4 s | 1.4–10 s (UL: < 10 s) | Not Guaranteed |
| Nodes per network | 300–1500 per cell | ~ 52000 per cell | 200 per gateway14 |
| Mobility | Connected mobility with some limitation (inter frequency handover) | No connected mobility (only idle mode reselection) | Better than NB-IoT |
| Energy efficiency | >10 years battery life of devices | >10–20 years battery life of devices | >10 years battery life of devices |
| Interference Immunity | Low | Low | Very high |
| Encryption | LTE encryption, 128/256-bit AES | LTE encryption, 128/256-bit AES | 128-bit AES |
| Attack | Active and passive Eavesdropping attacks, sniffing attacks, and DoS | Active and passive Eavesdropping attacks, sniffing attacks, and DoS | Replay attack, DoS, Eavesdropping, Bit-Flipping attack, and LoRa class B attacks [122] |
