DRX and DTX :how does it work?

DRX : Discontinuous Reception
DRX is a technique that allows the mobile station to power down significant amounts of its internal circuitry for a high percentage of the time when it is in the idle mode. The period of time when the mobile station will be powered down is commonly called the “Sleep mode”.

DRX feature depends on the network configuration. If the feature is activated by the network, the module will only read some of the available paging blocks, depending on parameters defined in the broadcasted system information ( paging group ID, frequency,….). If no paging block has to be read, the module will be able to go to sleep mode, increasing the battery life of the module:

For more information see 3GPP GSM 03.13 version 8.0.0 Release 1999
DTX: Discontinuous transmission
DTX is a technique that allows a device (module or Base Station) to avoid the transmission of speech frames during voice calls when “no speech” is present in the conversation. The main component of this feature is the “Voice Activity Detection”, which takes into account the fact that there is no voice activity during more than 50% of a normal conversation time.

This feature can be implemented in both downlink and uplink paths:

Downlink path: towards the module if the speech frames are being sent from the network (base station).

Uplink path: towards the network if the speech frames are being sent from the module.

The base station or the module will detect these “no speech” frames in a conversation in order to signal to the far end the lack of voice activity. Activating this feature will allow to:

Uplink path: the consumption of the module during the “no speech” voice frames will be reduced: the radio part of the module will be switched off.

Downlink path: the resources of the network will be optimized:

o Higher availability of resources for managing more users or

o Interferences will be reduced increasing the quality of the communication.

For more information see 3GPP TS 05.08, 3GPP TS 48.060