GPRS Multi slots TX-RX setting | Telit Cinterion IoT Developer Community
October 31, 2016 - 1:30pm, 4580 views
In BGS5 Hardware description manual, Table 14 Power Supply Ratings, current consumption values are changing according to the TX/RX configuration for the case GPRS Data transfer. In table, there are options like 1Tx/4Rx, 2Tx/3Rx, 4Tx/1Rx. The more TX number, the more current consumption.
I think, these values are gsm time slot configurations. There is an at command that sets slot class configuration. It is at^sgconf. Using this command, I can change the class as 10, 8 etc. BGS5 supports 8,9,10,11,12. By setting the multislot class number, the maximum number of Tx, Rx and Tx+Rx can be changed but exact selection like 1Tx/4Rx cannot be done.
Can we make this setting in some way, at command or other? Our purpose is to decrease power consumption by setting minimum Tx, for example 1Tx/4Rx.
The AT^SCFG="Radio/OutputPowerReduction" -command is "4" as delivered. That means the maximum
power reduction. This setting is the best for BGS5.
The AT^SGCONF=x command will reduce power consumption but to my understanding, selection of Tx and Rx slots inside a class like "8", is not possible.
The network given coding scheme will also affect ther power consumption and speed (CS1 to CS4).
On the other hand, a higher GPRS class will use less time to send the same amount of data, so the power saving is locally ok for the modem but
in terms of total power usage over time, the difference is not big.
What is the total power scenario in your application? How much is the BGS5 in the full communication mode?
There are also many other ways to reduce power consumption, like:
- AT^SPOW for serial port sleep mode activation, default "2,1000,3"; wakes up with CTS0/CTS1
Please note that the polling ***** for the GPIO's will increase during sleep mode- AT^SCFG: "Radio/Band",<rba> to exclude non used radio bands for a quicker network search (e.g. leaving only 900/1800MHz active)
- VUSB_IN signal must be high in order to enable USB sleep mode, as well
- power down and wake up with RTC (AT+CALA)
- RING0 signal can be used to wake up your possible other host if the USB has been shut down
This signal will raise if any call, message or URC will arrive.
- Java threads deactivated or waiting read
When calculating the power saving over time, please also note that there is a factor that is base station dependent.This is called DRX (Discontinuous reception) and it affects power saving. The time between so called paging messages
is from 0,47 to 2,12 seconds. Power saving happens between these messages.
In case you are not attached to the GSM network, the power saving period can be ouside of these limits.
For example you can use the Airplane mode AT+CFUN=4 or manually deregister using AT+COPS=2.
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Thanks for the answer.
In the hardware description manual, there are current consumption values for the cases 1Tx/4Rx, 2Tx/3Rx, 4Tx/1Rx separately. Probably, this Tx/Rx selection configurable.
The slots assignment is managed by the network as this is a network resource. And the network assigns the slots based on the data transmission and available resources probably. On the module it is only possible to set the class which determines the maximum allowed number of slots.
In the documentation there is described the data consumption for the particular slots configuration but it must have been measured in the test network or with a network simulator device where you can configure whatever you want on the network side and simulate any network conditions.
Thanks for the explanation.