Voice services over Adaptive Multi-user channels on One Slot (VAMOS)

Voice services over Adaptive Multi-user channels on One Slot (VAMOS)

Last updated: April 27, 2013

This section is only applicable to the lab applications.

VAMOS allows multiplexing of two users simultaneously on the same physical resource in the circuit switched mode both in downlink and in uplink, using the same timeslot number, ARFCN and TDMA frame number. Hence, a basic physical channel capable of VAMOS supports up to 4 TCH channels along with their associated control channels (FACCH and SACCH).

A pair of TCH channels along with their associated control channels sharing the same timeslot number, ARFCN and TDMA frame number is referred to as a VAMOS pair. Up to 2 VAMOS pairs can be supported by a basic physical channel capable of VAMOS. The TCH channels along with their associated control channels in a VAMOS pair are said to be in VAMOS mode and are referred to as VAMOS subchannels. In a VAMOS pair, each VAMOS subchannel shall be assigned a training sequence which is different from the training sequence assigned to the other VAMOS subchannel in that VAMOS pair.

The test set supports VAMOS test by combining a real MS and a fake MS into a VAMOS pair for downlink signal modulation. For the real MS, all call processing and test is normal. For the fake MS, the test set will simulate the link with PRBS data. New TSC set is introduced to support the VAMOS pair. Currently the test set allows VAMOS pair to take training sequence code (TSC) value in the same TSC set or different TSC sets. In the downlink direction, the test set modulates the signal with AQPSK during VAMOS transmission.

An MS indicates whether it supports VAMOS or not and the VAMOS supporting MS indicates its supported VAMOS level. An MS capable of either VAMOS I or VAMOS II level supports the set of training sequences in TSC Set 2 in addition to TSC Set 1. An VAMOS II capable MS supports the mapping of logical channels onto the physical channels as specified in 3GPP TS45.002 V11.0.0 table1a.

VAMOS Parameters

The VAMOS related parameters are shown below:

Parameter

GPIB Command

VAMOS Support

CALL:TCHannel:VAMOS:SUPPort

VAMOS Pair State

CALL:TCHannel:VAMOS:STATe

TCH TSC Set

CALL:TCHannel:TSCSet

TCH TSC

CALL:TCHannel:TSCode

VAMOS MS2 TSC Set

CALL:TCHannel:VAMOS:MS2:TSCSet

VAMOS MS2 TSC

CALL:TCHannel:VAMOS:MS2:TSCode

VAMOS MS2 DTX State

CALL:TCHannel:VAMOS:MS2:DTX[:STATe]

VAMOS SCPIR

CALL:TCHannel:VAMOS:SCPir

Deferred TSC Set

CALL:SETup:TCHannel:TSCSet

Deferred TCH TSC

CALL:SETup:TCHannel:TSCode

Deferred VAMOS MS2 TSC Set

CALL:SETup:TCHannel:VAMOS:MS2:TSCSet

Deferred VAMOS MS2 TSC

CALL:SETup:TCHannel:VAMOS:MS2:TSCode

VAMOS Shifted SACCH State

CALL:TCHannel:VAMOs:SSACch:STATe

How Do I Set up and Use the VAMOS Feature?

The following procedure details how to access and use the VAMOS feature.

  1. Press the CALL SETUP key.
  2. Press the TCH Parameter ( F8 ) key.
  3. Press the More key on the lower left corner to display the TCH parms ( 3 of 3 ).
  4. Press VAMOS Parameters ( F10 ) key. Use the knob to highlight the parameter and change the value.

Operating Considerations

The VAMOS is applicable to both Active Cell mode the Test modes with TCH channel presents.

   
NOTE
The BER measurement and Tx measurements is supported as before. However, Tx measurement will not be supported when the TSC Set is set to 2.

   

Related Topics


CALL:TCHannel

CALL:SETup