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Overview
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Frequency Bands
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Frequency Range
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GSM 900
channels 0 – 124, 955 – 1023
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876.2 to 914.8 MHz (uplink)
921.2 to 959.8 MHz (downlink)
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GSM 1800
channels 512 – 885
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1710.2 to 1784.8 MHz (uplink)
1805.2 to 1879.8 MHz (downlink)
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GSM 1900 (Americas)
channels 512 – 810
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1850.2 to 1909.8 MHz (uplink)
1930.2 to 1989.8 MHz (downlink)
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GSM 850 (Americas)
channels 128 – 251
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824.2 to 848.8 MHz (uplink)
869.2 to 893.8 MHz (downlink)
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Channel spacing
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200 kHz
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Modulation
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8-PSK (8-Phase Shift Keying) or
GMSK (Gaussian Minimum Shift Keying)
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Symbol rate
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270,833 symbols/s
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Bits per symbol
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3
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Access format
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TDMA (time-division multiple access)
TDD/FDD (time and frequency division duplex)
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Number of channels per carrier
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8 time slots per TDMA frame
(4.615 ms)
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Data
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Up to 384 kbit/s
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Power control
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Yes, in 2-dB steps over a range of 30 dB
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Applications
EDGE (“Enhanced Data rates for Global Evolution”) is a step in the evolution of GSM/GPRS. The objective of the EDGE technology is to increase data transmission rates and spectrum efficiency and to facilitate new applications and increased capacity for mobile use.
In addition, EDGE supports the popular short message service (SMS) and its extension, the multimedia message service (MMS), both services are used in a number of business applications. Mobile Internet may now be supported due to higher data rates.
Technology in brief
EDGE is an expansion of the GSM/GPRS protocol to support higher data rates. This is accomplished by utilising 8-PSK (8-Phase Shift Keying) modulation technique and modulation coding schemes at the physical layer. This modulation provides an increase from 1 to 3 bits per symbol, thus improving the overall data throughput. The physical layer now consists of nine modulation coding schemes (MCS), which may be utilised for either the downlink (forward link) or the uplink (reverse link).
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Scheme
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Modulation
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Data Rate (kbit/s)
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MCS-1
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GMSK
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8.8
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MCS-2
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GMSK
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11.2
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MCS-3
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GMSK
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14.8
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MCS-4
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GMSK
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17.6
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MCS-5
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8-PSK
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22.4
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MCS-6
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8-PSK
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29.6
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MCS-7
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8-PSK
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44.8
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MCS-8
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8-PSK
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54.4
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MCS-9
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8-PSK
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59.2
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In addition to the modulation coding schemes, there are enhancements to the interleaving techniques, addressing and packet handling. The user may utilise more than 1 time slot per frame, thus increasing the overall data throughput.
To minimise network issues, EDGE utilises the same bandwidth and frequencies as the current GSM/GPRS protocol.
Typical measurements
Numerical measurements:
Error vector magnitude, frequency error, peak power, BLER
Graphical representations:
Power vs. time, modulation spectrum
Willtek Test Instruments
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