User's Manual

PART 2 – Embedded Wireless Modems Chapter 5 – SocketModem HSDPA
Multi-Tech Systems, Inc. Universal Socket Hardware Guide for Developers (S000342K) 90
Power Saving While Attached to GSM Networks
The power saving possibilities while attached to a GSM network depend on the paging timing cycle of the base
station. The duration of a power saving interval can be calculated using the following formula:
t = 4.615 ms (TDMA frame duration) * 51 (number of frames) * DRX value.
DRX (Discontinuous Reception) is a value from 2 to 9, resulting in paging intervals between 0.47 and 2.12
seconds. The DRX value of the base station is assigned by the GSM network operator.
In the pauses between listening to paging messages, the SocketModem resumes power saving, as shown in the
figure below.
Power Saving and Paging in GSM Networks
The varying pauses explain the different potential for power saving. The longer the pause the less power is
consumed.
Generally, power saving depends on the SocketModem’s application scenario and may differ from the above
mentioned normal operation. The power saving interval may be shorter than 0.47 seconds or longer than 2.12
seconds.
Power Saving While Attached to WCDMA Networks
The power saving possibilities while attached to a WCDMA network depend on the paging timing cycle of the
base station.
During normal WCDMA operation, i.e., the SocketModem is connected to a WCDMA network, the duration of a
power saving period varies. It may be calculated using the following formula:
t = 2DRX value * 10 ms (WCDMA frame duration).
DRX (Discontinuous Reception) in WCDMA networks is a value between 6 and 9, thus resulting in power saving
intervals between 0.64 and 5.12 seconds. The DRX value of the base station is assigned by the WCDMA
network operator.
In the pauses between listening to paging messages, the SocketModem resumes power saving, as shown in the
figure below.
Power Saving and Paging in WCDMA Networks
The varying pauses explain the different potential for power saving. The longer the pause the less power is
consumed.
Generally, power saving depends on the SocketModem’s application scenario and may differ from the above
mentioned normal operation. The power saving interval may be shorter than 0.64 seconds or longer than 5.12
seconds.
Power Saving During Network Search, GSM/WCDMA
The power saving interval during network search depends on the network registration mode configured for the
modem. This mode can be specified with the AT^SCFG command parameter MEopMode/RM:
• In "Fast" mode, the power saving interval may last for up to 5 seconds.
• In "Normal" mode, the power saving interval may last for up to 40 seconds.
For details on how to configure the AT^SCFG parameter MEopMode/RM see the HSDPA AT Command Guide.