About the GSM/EDGE Options
R&S®SMW-K40/-K41
10User Manual 1175.6684.02 ─ 16
The modulation data is continuously inserted into the chosen slots. In this fashion, the
data generator uses a digital signal processor to generate a data stream complete with
modulation data and control signals for power ramping.
This data stream is converted into I/Q signals in the modulation encoder.
The R&S SMW processes the signal depending on the configured modulation scheme
and selected symbol rate mode:
●In accordance with the GSM standard, the MSK modulation type is set by default to
a symbol rate of 270.833 ksymb/s and gauss filtering.
You can adjust the symbol rate. Also, you can use an FSK modulation with configu-
rable span.
●In accordance with the standard, the EDGE slots use 8PSK modulation type with
3/8 rotation at a symbol rate of 270.833 ksymb/s and gauss linearized filtering.
●In accordance to EDGE evolution specifications (option R&S SMW-K41), the
EDGE evolution slots in a normal burst (NB) are 16QAM or 32QAM modulated.
They use a symbol rate of 270.833 ksymb/s and are gauss linearized filtered. The
EDGE evolution slots in higher symbol rate bursts (HB) are QPSK, 16QAM or
32QAM modulated. They use a symbol rate of 325 ksymb/s and are spectrally nar-
row or wide pulse shape filtered.
●In accordance to VAMOS specifications (option R&S SMW-K41), the slots are
AQPSK modulated at a symbol rate of 270.833 ksymb/s and gauss linearized filter-
ing.
You can configure the GSM/EDGE signal in on of the following modes:
●Mode unframed - a signal with standard-compliant modulation parameters but
without slot and frame structure is generated.
●Mode frame (single) - a signal consisting of a frame is generated; it is also possi-
ble to choose half rate bursts and to define multi-slots.
●Mode frame (double) - a signal consisting of two frames is generated; the frames
are repeated according to a defined default.
2.3 VAMOS (Voice services over Adaptive Multi-User
channels on One Slot)
According to 3GPP TS 45.001, with VAMOS it is possible to serve two MS simultane-
ously on the same physical resource. Thus the voice channel capacity in the CS
domain can be doubled.
Each of the two VAMOS users is assigned a so-called VAMOS subchannel, i.e. the
physical radio resource is split into two subchannels, one for each VAMOS user. The
two subchannels are separated in uplink and downlink via training sequences. For this
purpose, 3GPP TS 45.002 defines two sets of training sequence codes (TSC). One
VAMOS user/subchannel gets a training sequence from TSC set 1, the other from TSC
set 2. This ensures that the two training sequences have a low cross-correlation. All
mobiles must support TSC set 1, but only mobiles explicitly indicating support for
VAMOS must also support TSC set 2.
VAMOS (Voice services over Adaptive Multi-User channels on One Slot)
