SARA-R42 - Application note
UBX-20050829 - R02
PSM, eDRX and deep-sleep mode
Page 31 of 58
C1-Public
reliable. Customers are advised to test out both parameters to come to a value that best fits their use
case and requirements in terms of power consumptions, MT data delay and reliability.
eDRX can be also used along with the PSM feature. In this case eDRX is used while the T3324 timer is
running. When the UE tries to negotiate both PSM and eDRX features, the network interprets the
request in the following way: if the requested TeDRX and T3412 extended values have similar
durations then the network interprets that the UE would like to use eDRX or PSM, if the requested
TeDRX cycle is at least one order of magnitude smaller than the requested T3412 extended value then
the network interprets that the UE would like to use eDRX during the T3324 active time. In the latest
case, for paging reliability, it is also advisable to request at least two TeDRX cycles during the T3324
active time (see
Power Save Mode
Paging window (~2.56s
cycle)
eDRX cycle
–
N Hyper-frames of 10.24 s
T3324 period
Figure 4: Paging listening when DRX, eDRX and PSM are enabled. In detail paging occasions are listened to during the eDRX
PTW according to the network configured DRX cycle. eDRX is used during the PSM T3324 Active Time period.
8.3.1.1
Encoding of timer TeDRX
The TeDRX length, i.e. the requested eDRX cycle duration, is encoded as per Table 10.5.5.32/3GPP TS
24.008
0 0 0 0
5.12 seconds
0 0 0 1
10.24 seconds
0 0 1 0
20.48 seconds
0 0 1 1
40.96 seconds
0 1 0 0
61.44 seconds
0 1 0 1
81.92 seconds
0 1 1 0
102.4 seconds
0 1 1 1
122.88 seconds
1 0 0 0
143.36 seconds
1 0 0 1
163.84 seconds
1 0 1 0
327.68 seconds
1 0 1 1
655.36 seconds
1 1 0 0
1310.72 seconds
1 1 0 1
2621.44 seconds
1 1 1 0
5242.88 seconds
1 1 1 1 10485.76 seconds
☞
All other values shall be interpreted as 0000.
☞
In LTE Cat M1 for the eDRX cycle length duration of 5.12 s the eDRX cycle parameter 'TeDRX' is
not used.
