| Frequency bands |
GSM 900
channels 0 – 124, 955 – 1023 |
876.2 to 914.8 MHz (uplink),
921.2 to 959.8 MHz (downlink) |
GSM 1800
channels 512 – 885
|
1710.2 to 1784.8 MHz (uplink),
1805.2 to 1879.8 MHz (downlink) |
GSM 1900 (Americas)
channels 512 – 810
|
1850.2 to 1909.8 MHz (uplink),
1930.2 to 1989.8 MHz (downlink) |
GSM 850 (Americas)
channels 128 – 251
|
824.2 to 848.8 MHz (uplink),
869.2 to 893.8 MHz (downlink) |
| Channel spacing |
200 kHz |
| Modulation |
GMSK (Gaussian Minimum Shift Keying), phase shifts of π/2 (90°) on symbol transitions |
| Symbol rate |
270.833 symbols/s |
| Bits per symbol |
1 |
| Access format |
TDMA (time-division multiple access)
TDD/FDD (time and frequency division duplex) |
| Number of channels per carrier |
8 time slots per TDMA frame (4.615 ms)
148 bits per time slot, equivalent to 577 µs |
| Speech |
Digital transmission with one out of several possible vocoders:
Full rate speech (13 kbit/s)
RPE-LTP (regular pulse excited code with long term prediction)
Enhanced full rate speech (12.2 kbit/s)
ACELP (algebraic code excited linear prediction)
Half rate speech (5.6 kbit/s)
VSELP (vector sum excited linear predictor)
Adaptive multirate (AMR), dynamic operation on full and half rate channel depending on capacity and reception quality |
| Power control |
Yes, in 2-dB steps over a range of 30 dB |
