Traffic Channel
A traffic channel ( TCH ; German : traffic channel) is a channel in a cellular network that is used to transmit data or voice.
GSM traffic channels
The traffic channels of the GSM mobile radio system can be divided into three groups according to their use:
Traffic channels for speech
| Short name | designation | Data transfer rate (gross) | used codec |
|---|---|---|---|
| TCH / FS | full rate traffic channel for speech | 22.8 kbit / s | FR |
| TCH / HS | half rate traffic channel for speech | 11.4 kbit / s | MR |
| TCH / EFS | enhanced full rate traffic channel for speech | 69.6 kbit / s | EFR |
| TCH / AFS | adaptive full rate traffic channel for speech | 22.8 kbit / s | AMR |
| TCH / AHS | adaptive half rate traffic channel for speech | 11.4 kbit / s | AMR |
| TCH / WFS | adaptive full rate traffic channel for wideband speech | 22.8 kbit / s | AMR-WB |
| O-TCH / AHS | adaptive half rate 8PSK traffic channel for speech | 34.2 kbit / s | AMR |
| O-TCH / WFS | adaptive full rate 8PSK traffic channel for wideband speech | 68.4 kbit / s | AMR-WB |
| O-TCH / WHS | adaptive half rate 8PSK traffic channel for wideband speech | 34.2 kbit / s | AMR-WB |
Traffic channels for circuit-switched data transmission
| Short name | designation | Data transfer rate (gross) |
|---|---|---|
| TCH / F9.6 | full rate traffic channel for 9.6 kbit / s user data | 22.8 kbit / s |
| TCH / F4.8 | full rate traffic channel for 4.8 kbit / s user data | 22.8 kbit / s |
| TCH / H4.8 | half rate traffic channel for 4.8 kbit / s user data | 11.4 kbit / s |
| TCH / H2.4 | half rate traffic channel for up to 2.4 kbit / s user data | 11.4 kbit / s |
| TCH / F2.4 | full rate traffic channel for up to 2.4 kbit / s user data | 22.8 kbit / s |
| TCH / F14.4 | full rate traffic channel for 14.4 kbit / s user data | 22.8 kbit / s |
| E-TCH / F28.8 | enhanced circuit switched full rate traffic channel for 28.8 kbit / s user data | 68.4 kbit / s |
| E-TCH / F32.0 | enhanced circuit switched full rate traffic channel for 32.0 kbit / s user data | 68.4 kbit / s |
| E-TCH / F43.2 | enhanced circuit switched full rate traffic channel for 43.2 kbit / s user data | 68.4 kbit / s |
Traffic channels for packet-switched data transmission
| Short name | designation | Data transfer rate (gross) |
|---|---|---|
| PDTCH | Packet data traffic channel | Max. 138 kbit / s |
A full-rate TCH has a data transmission rate of 22.8 kbit / s (gross), a half-rate TCH of 11.4 kbit / s. Since the frequency of bit errors in radio transmission is significantly higher than in wired data transmission (order of magnitude between 10 −3 to 10 −1 ), numerous error correction methods must be used and the errors must be corrected by adding redundancy . What remains for voice transmission is a transmission rate of 13 kbit / s.
In an ISDN , the B-channel corresponds to the TCH.
Individual evidence
- ↑ 3GPP TS 45.002: Multiplexing and multiple access on the radio path ( English , ZIP / DOC; 569 KB) October 1, 2009. Accessed December 8, 2009.