EDGE Test and Measurements

Agenda EDGE Measurements VSA to test EDGE EDGE maintains the modulation scheme used in GSM (GMSK) and IS-136 (/4-DQPSK) for low data rates and for backward compatibility. For higher data rates, the 8-PSK modulation scheme is used. However, the same TS format is used with the 156.25 symbols per TS. For 8-PSK, this translates into three times the bit rate for GSM.

Agenda EDGE Measurements VSA to test EDGE EDGE maintains the modulation scheme used in GSM (GMSK) and IS-136 (/4-DQPSK) for low data rates and for backward compatibility. For higher data rates, the 8-PSK modulation scheme is used. However, the same TS format is used with the 156.25 symbols per TS. For 8-PSK, this translates into three times the bit rate for GSM.

GSM/EDGE TX Measurements Power Mean Transmit Power Power vs. Time Modulation Quality Phase Frequency error (GSM) EVM (EDGE) Spectral Emissions Output RF Spectrum (ORFS) Modulation spectrum Switching (transient) spectrum TX/RX Band Spurious Cross-Band Spurious

Key Measurements of TX

GSM/EDGE RX Measurements Sensitivity Frame erasure rate (FER) Residual bit error rate (RBER) Class Ib RBER Class II Sensitivity search Sensitivity Selectivity Co-channel rejection Adjacent channel selectivity Alternate channel selectivity

GSM vs. EDGE

GSM Modulation - 0.3 GMSK (gaussian filtered minimum shift keying) “1” = -67.708 kHz Data “0” = +67.708 kHz Symbol rate = Bit rate = 270.833 kB/s Phase +90 deg -90 deg Q I

Standard 8 PSK Constellation EDGE Modulation 8 PSK constellation rotates 3/8 radians (67.5 deg) per symbol period Rotation prevents zero crossings, reducing peak-to-average power (1,1,1) t = 0 (symbols) (1,1,1) t = 1 (1,1,1) t = 2 (1,1,1) t = 3 3π/8 radians ... Standard 8 PSK Constellation

EDGE vs. GSM Vector (Constellation) Diagrams

Effect of Poor Modulation Quality Received I Q Transmitted Interference I Q

EDGE Error-Vector Magnitude

{ Error Vector Magnitude Q I Magnitude Error (IQ error mag) H Error Vector Magnitude { I Q Magnitude Error (IQ error mag) Error Vector Reference Signal Phase Error (IQ error phase) Measured Signal 

The EVM Measurement Process 001110 Modulator Demodulator Reference Waveform Input signal Measured Waveform

Error Vector Magnitude (time domain) H Error Vector Magnitude (time domain) This display shows the error vector magnitude at each point in time. The red lines show the symbol times. Errors can be seen at the symbol points in and between.

EVM Requirements for EDGE EVMRMS EVMpeak EVM-95th-percentile

EVM Requirements in EDGE Specs

We found in the GSM 11.10

Reasons for Bad EVM Example Modulation Errors Q Q I I Gain Imbalance H Reasons for Bad EVM Example Modulation Errors Q Q I I Gain Imbalance Phase Imbalance Q I Origin Offset

Frequency-Time Power Distribution 1 2 3 4 5 6 7 Amplitude Timeslot Frequency 1 2 3 4 5 6 ARFCN (Channel Frequency)

Interference - Power Measurements Power versus Time Timeslot Output RF Spectrum ARFCN

EDGE Power Vs Time

Power vs. Time Time Amplitude Frequency ABC

EDGE Power Vs. Time

Power vs. Time Masks for GSM

Power vs. Time Masks for EDGE The amplitude modulation in EDGE requires that a different power versus time mask be used.

EDGE ORFS

Adjacent Channel Power (ACP) Output RF Spectrum (ORFS) Adjacent Channel Power (ACP) Due to Modulation Due to Switching

ORFS Specification (dBc) Tuned Average Power Across Useful Part of Burst Offset kHz Power Channel Center Time Frequency

Interference Problems from ACP (ORFS) ARFCN 1 39 dBm 43 dBm 39 dBm (18dbm @ 200kHz offset) B ARFCN 4 39 dBm C ARFCN 2 A ARFCN 1 D ARFCN 3

Agenda EDGE Measurements VSA to test EDGE EDGE maintains the modulation scheme used in GSM (GMSK) and IS-136 (/4-DQPSK) for low data rates and for backward compatibility. For higher data rates, the 8-PSK modulation scheme is used. However, the same TS format is used with the 156.25 symbols per TS. For 8-PSK, this translates into three times the bit rate for GSM.

VSA – EDGE Modulation Analysis EDGE maintains the modulation scheme used in GSM (GMSK) and IS-136 (/4-DQPSK) for low data rates and for backward compatibility. For higher data rates, the 8-PSK modulation scheme is used. However, the same TS format is used with the 156.25 symbols per TS. For 8-PSK, this translates into three times the bit rate for GSM.

VSA – EDGE EVM EDGE maintains the modulation scheme used in GSM (GMSK) and IS-136 (/4-DQPSK) for low data rates and for backward compatibility. For higher data rates, the 8-PSK modulation scheme is used. However, the same TS format is used with the 156.25 symbols per TS. For 8-PSK, this translates into three times the bit rate for GSM.

VSA – EDGE PvT EDGE maintains the modulation scheme used in GSM (GMSK) and IS-136 (/4-DQPSK) for low data rates and for backward compatibility. For higher data rates, the 8-PSK modulation scheme is used. However, the same TS format is used with the 156.25 symbols per TS. For 8-PSK, this translates into three times the bit rate for GSM.

VSA – EDGE ORFS EDGE maintains the modulation scheme used in GSM (GMSK) and IS-136 (/4-DQPSK) for low data rates and for backward compatibility. For higher data rates, the 8-PSK modulation scheme is used. However, the same TS format is used with the 156.25 symbols per TS. For 8-PSK, this translates into three times the bit rate for GSM.

Summary EDGE an enhancement to GSM provides higher data rates in the same spectrum by using a higher density modulation. most of the GSM measurements apply to the EDGE waveform for modulation quality EVM is used for the 8-PSK signal, instead of phase error

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