GSM Timeslot & Frequency Specifications

 

These diagrams show how timeslots and corresponding frequencies are allocated in the GSM (Global System for Mobile Communications, originally Groupe Spécial Mobile), DCS (Digital Communications System), and PCS (Personal Communications Service) bands. A GSM Multiframe is the basic unit, and is 120 ms long. There are 26 Frames in each Multiframe, with each Frame being 4.61538 ms long (120 ms/26). Within each Frame are 8 Timeslots at 576.92 us per Timeslot (577 us in round numbers). Finally, there are 156.25 Bits per Timeslot, each Bit being 3.69231 us long.

 

Tables of all GSM Frequency Bands, GSM Frequency Calculations, and GSM Timing are provided at the bottom of the page.

 

GSM timeslot chart drawing frames timing

GSM timeslot chart drawing frames timing uplink downlink

GSM 900

GSM timeslot chart drawing frames timing frequency

DCS 1800

GSM timeslot chart drawing frames timing DCS

PCS 1900

GSM timeslot chart drawing frames timing PCS

GSM Frequency Bands

SystemBandUplink (MHz)Downlink (MHz)Channel Number
T-GSM 380380380.2 - 389.8390.2 - 399.8Dynamic
T-GSM 410410410.2 - 419.8420.2 - 429.8Dynamic
GSM 450450450.4 - 457.6460.4 - 467.6259 - 293
GSM 480480478.8 - 486.0488.8 - 496.0306 - 340
GSM 710710698.0 - 716.0728.0 - 746.0Dynamic
GSM 750750747.0 - 762.0777.0 - 792.0438 - 511
T-GSM 810810806.0 - 821.0851.0 - 866.0Dynamic
GSM 850850824.0 - 849.0869.0 - 894.0128 - 251
P-GSM 900900890.0 - 915.0935.0 - 960.01 - 124
E-GSM 900900880.0 - 915.0925.0 - 960.0975 - 1023, 0-124
R-GSM 900900876.0 - 915.0921.0 - 960.0955 - 1023, 0-124
T-GSM 900900870.4 - 876.0915.4 - 921.0Dynamic
DCS 180018001710.0 - 1785.01805.0 - 1880.0512 - 885
PCS 190019001850.0 - 1910.01930.0 - 1990.0512 - 810
 

GSM Frequency Calculations

Frequency BandARFCN RangeUplink Frequency
(MHz)		Downlink Frequency
(MHz)
P-GSM 900 1..124890+0.2*ARFCN935+0.2*ARFCN
E-GSM 900 0..124
975..1023		890+0.2*ARFCN
890+0.2*(ARFCN-1024)		935+0.2*ARFCN
935+0.2*(ARFCN-1024)
DCS 1800 512..8851710.2+0.2*(ARFCN-512) 1805.2+0.2*(ARFCN-512)
PCS 1900 512..810 1850.2+0.2*(ARFCN-512) 1930.2+0.2*(ARFCN-512)
R-GSM 900 0..124
955..1023		890+0.2*ARFCN
890+0.2*(ARFCN-1024)		935+0.2*ARFCN
935+0.2*(ARFCN-1024)
GSM 450 259..293 450.6+0.2*(ARFCN-259) 460.6+0.2*(ARFCN-259)
GSM 480 306..340 479+0.2*(ARFCN-306) 489+0.2*(ARFCN-306)
GSM 850 128..251 824.2+0.2*(ARFCN-128) 869.2+0.2*(ARFCN-128)
GSM 750 438..511 747.2+0.2*(ARFCN-438) 777.2+0.2*(ARFCN-438)

 

GSM Timing

 SymbolBurstsFramesTimeRate
Symbol 1 1/8 1/1250 48/13 μs (3.692 μs) 270833/s
Burst 156.25 1 1/8 15/26 ms (576.9 μs) 1733/s
Frame 1250 8 1 60/13 ms (4.615 ms) 216.6/s
26 Multiframe 32500 208 26 120 ms 8.333/s
51 Multiframe 63750 408 51 235.4 ms 4.248/s
52 Multiframe 65000 416 52 240 ms 4.167/s
Superframe 2071875000 84864 1326 6120 ms 9.803/min
Hyperframe 4.2432E+12 173801472 2715648 3h:28m:53.760s6.893/day