Review Article
Wireless Communications in Smart Rail Transportation Systems
Table 4
Example of different wireless communications systems customized for critical and noncritical communications.
| Parameter | Critical | Noncritical | GSM-R | LTE-R | LTE | WLAN 802.11xx | Satellite |
| Frequency | Uplink: 876–880 MHz downlink: 921–925 MHz | 450 MHz, 800 MHz, 1.4–1.8 GHz | 800 MHz, 1.8 GHz, 2.6 GHz | 2.4/5.7 GHz, 24/28/33 mmW | 12/14 GHz | Bandwidth | 0.2 MHz | 1.4–20 MHz | 1.4–20 (100) MHz | 80 (160) MHz | 10–16 MHz | Modulation/multiple access | GMSK | QPSK | M-QAM | M-QAM | QPSK | FDD + TDM | FDD + OFDM | FDD + OFDM | TDD + OFDM | FDD | Peak data rate, downlink/uplink | 172/172 Kbps | 50/10 Mbps | 100/50 Mbps | 433.3 Mbps | 10/1 Mbps | Peak spectral efficiency | 0.33 bps/Hz | 2.55 bps/Hz | 16.32 bps/Hz | 4.8 bps/Hz | 1 bps/Hz | Maximum transmission delay | <50 ms | <100 ms | <1 s | <1 s | <1.5 s | Data transmission | Requires voice call connection | Packet switching | Packet switching | Packet switching | Packet switching | Packet retransmission | No (serial data) | UDP packets, 0 retransmissions | IP packets with up to 5 retransmissions | IP packets, up to 5 retransmissions | IP packets, 0 retransmissions | MIMO | SISO | | , , | , up to 15 | no | (diversity) | Mobility | Max. 500 km/h | Max. 500 km/h | Max. 350 km/h | Max. 250 km/h | >500 Km/h | Handover success rate | ≥99.5% | ≥99.9% | ≥99.5% | ≥99.5% | — | Handover procedure | Hard | Soft | Hard/soft | Hard/soft | No handover | All IP (native) | No | Yes | Yes | Yes | yes |
|
|