6.5.10 Discontinuous Reception (DRX)

03.643GPPGeneral Packet Radio Service (GPRS)Overall description of the GPRS radio interfaceStage 2TS

NOTE: The text in this subclause is informative. The normative text is in GSM 05.02 [11]. Where there is a conflict between these descriptions, the normative text has precedence.

DRX (sleep mode) shall be supported when the MS is in Packet Idle mode. DRX is independent from MM states Ready and Standby.

Negotiation of DRX parameters is per MS. An MS may choose to use DRX or not together with some operating parameters. The following parameters are established:

DRX/non-DRX indicator
It indicates whether the MS uses DRX or not.

DRX period
A conditional parameter for MSs using DRX to determine the right paging group. The DRX period is defined by the parameter SPLIT_PG_CYCLE.

Non-DRX timer
A conditional parameter for MSs using DRX to determine the time period within which the non-DRX mode is kept after leaving the Transfer state. The support for this feature is optional on the network side and the information about the maximum supported value for the timer in the cell is broadcast on PBCCH.

An MS in DRX mode is only required to monitor the radio blocks defined by its paging group as defined in GSM 05.02 [11].

Paging group definition based on SPLIT_PG_CYCLE is optional on CCCH for both BTS and MS. If not supported, the definition based on BS_PA_MFRMS shall be used. The parameters used to define the paging group for GPRS are shown in the Table 5, together with the corresponding GSM parameters. BS_PCC_CHANS is the number of PDCHs containing PCCCH. For Compact, BS_PCC_CHANS is the number of radio frequency channels per cell carrying CPCCCHs including the radio frequency channel carrying the CPBCCH.

An MS in non-DRX mode is required to monitor all the radio blocks where PCCCH or (for Compact) CPCCCH may be mapped on the PDCH defined by its paging group.

When page for circuit-switched services is conveyed on PPCH, it follows the same scheduling principles as the page for packet data. The same is valid for scheduling of resource assignments for downlink packet transfers for MSs in Ready State (i.e. where no paging is performed).

The MS may need to monitor also PNCH or CPNCH in the case of PTM-M services.

NOTE: Paging reorganisation may be supported in the same way as for circuit switched GSM.

Table 5: Parameters for DRX operation

Parameter

GPRS

Corresponding GSM parameters

PCCCH

CCCH

CCCH

DRX period

SPLIT_PG_CYCLE

BS_PA_MFRMS *) SPLIT_PG_CYCLE **)

BS_PA_MFRMS

Blocks not available for PPCH or CPPCH per multiframe

BS_PAG_BLKS_RES + BS_PBCCH_BLKS

BS_AG_BLKS_RES

BS_AG_BLKS_RES

Number of physical channels containing paging;

or

for Compact, number of radio frequency channels per cell carrying CPCCCHs including the radio frequency channel carrying the CPBCCH.

BS_PCC_CHANS

BS_CC_CHANS

BS_CC_CHANS

*) Only when DRX period split is not supported. **) Only when DRX period split is supported.