GSM and EDGE Modulation and Band Information

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The standard includes multiple traffic channels, a control channel, and a cell broadcast channel. Although the GSM specification defines a channel spacing of 200 kHz, it is worth noting that service providers often space their channels 400 kHz apart.
GSM 450, GSM 480, GSM 900, GSM 850, DCS 1800, and PCS 1900 are GSM-defined frequency bands. The term GSM 900 is used for any GSM system operating in the 900 MHz band, which includes P-GSM, E-GSM, and R-GSM. Primary (or standard) GSM 900 band (P-GSM) is the original GSM band. Extended GSM 900 band (E-GSM) includes all the P-GSM band plus an additional 50 channels. Railway GSM 900 band (R-GSM) includes all the E-GSM band plus additional channels.
DCS 1800 is an adaptation of GSM 900, created to allow for smaller cell sizes for higher system capacity. PCS 1900 is intended to be identical to DCS 1800 except for frequency allocation and power levels. The term GSM 1800 is sometimes used for DCS 1800, and the term GSM 1900 is sometimes used for PCS 1900. For specifics on the bands, refer to "GSM Band Data" table in the measurement guide.
The framing structure for GSM measurements is based on a hierarchical system consisting of timeslots, TDMA frames, multiframes, superframes, and hyperframes. One timeslot consists of 156.25 (157) symbol periods including tail, training sequence, encryption, guard time, and data bits. Eight of these timeslots make up one TDMA frame. Either 26 or 51 TDMA frames make up one multiframe. Frames 13 and 26 in the 26 frame multiframe are dedicated to control channel signaling.
EDGE (Enhanced Data for Global Evolution) is an enhanced version of GSM that uses 8PSK (8-Phase Shift Keying) as opposed to the GMSK (Gaussian Minimum Shift Keying) of GSM. EDGE can therefore transmit three times as many bits per symbol as GSM while using the same framing structure.