Patent ID: 12250635

FIG.1schematically shows a user equipment1of the type to which the present invention is applied as an embodiment. It is capable of operating with a base station2of a cellular network, supporting the technology standard of 4G, 5G or beyond.

The user equipment is in particular an IoT device, like a metering device measuring the consumed current. Hence the user equipment1is composed from an application part9, coupled with a user interface8, and a communication part. The communication part in particular comprises processing circuitry10, like a central processing unit (CPU). Depending upon the architecture of the user equipment1one processing circuitry for the application (application processor) and one for the communication unit (baseband processor) is available, or the same processing circuitry is shared for both tasks.

Preferably the user equipment1comprises a battery or other power supply. The user equipment1needs to comply with a power budget for the regular operations in order to achieve a given lifetime of the battery without recharging. The user equipment, resp. the communication unit further comprises a transceiver6, which incorporates transmitting and receiving circuitry, which combines all hardware components that are needed for carrying out radio frequency (RF) tasks towards the base station2. For fulfilling this task the transceiver6is coupled to the at least one antenna7. As preferably the user equipment is operating in narrowband modes, normally one antenna should be sufficient, which is also advantageous for power saving reasons.

Additionally the exemplifying user equipment1comprises memory5, both permanent and volatile, for storing protocol stack software, and potentially any other type of software needed by the communication unit and/or application part9.

Finally an USIM4for storing the access credentials for getting access to the cellular network of the base station2is communicatively coupled to the user equipment1. This is in particular a removable USIM (or UICC etc.), but also soldered variants are a possible option for this type of user equipment.

InFIG.2it is shown a flow chart for an exemplifying embodiment of the proposed inventive method.

It starts in step S1with the initialisation step, where the application9of the user equipment1activates—in particular by means of user interface8interaction—the PO (power optimized) mode, which is basically incorporated by the inventive method.

Then the process flow continues in step S2, where the user equipment, in particular the communication unit sets the initial values for the parameter governing the execution of the PO mode.

This comprises in particular an initial reference power value representing the TX power needed for carrying out a TAU request. This reference power value is in particular preset by carrying out a TAU request and determining the TX power value spent for this TAU.

Further delay times etc. are set in step S2.

After the TAU was carried out, the user equipment is running for a defined period of time in a power reduced mode in step S3. This might be an idle mode, but preferably it is a sleep mode like the PSM (power saving mode), as it is defined in the technology standard for LTE Cat-M etc.

During this time a data packet for payload transmission is made available by the application9to the communication unit of the user equipment1.

The PSM lasts for a certain time, in particular requested in conjunction with the TAU request from step S3.

When this period expired the process flow jumps to step S4. In this step the user equipment is awaken and carries out a second TAU request, and again measures the TX power for this second TAU request. The first (previous) and second (current) TX power values for the respective TAUs are compared.

The process floor branches to Step S5or S7in dependence of this comparison. If the second TX power value is higher by a predetermined threshold value of X dB then the transmission of the data packet shall be delayed, and the process flow jumps to step S5.

If this is not the case, that means the both TX power values have roughly the same value, then the process flow branches to step S7.

In step S5it is however first checked if the maximum delay tolerance value for delayed data transmission is reached. For this a preferably counter is maintained, which is increased when a delay is carried out.

Alternatively the maximum delay tolerance is measured in time e.g. since last successful payload data transmission. For that no timer is needed.

As this is the first time of delay, the process flow branches back to step S3and the user equipment1activates another idle/PSM phase. The reference power value remains the same. Further the counter for delays, if needed, is increased.

Should however the maximum delay tolerance be exceeded, then the process flow branches to step S6. Here possible adaptation of the parameter of the flow are foreseen, e.g. the predetermined threshold value xDB, the maximum delay tolerance or the PSM duration.

Afterwards the process flow branches to step S7and carries out the payload data transmission to the remote server via the base station2.

In an optional step S8it is then checked, in particular based on the required TX power for the data transmission, if the expected lifetime of the battery can be achieved when the currently happening amount of TX power is needed for TAU and payload data transmission. If not, further parameter amendments or an indication to the application, so that the operator gets informed through the user interface and may take appropriate steps to act in time, that means long time before the battery is empty.

InFIG.3a time/power diagram shows the impact of applying the exemplifying embodiment of the inventive method on a user equipment.

The time is shown on the horizontal axis, the needed power for single operation in the vertical axis. The time points T1-T10depict certain events that are described below. The hatched areas below the events indicate the needed TX power for executing the tasks by the exemplifying user equipment. The higher the area, the more power is invested on the same time unit. The square measure of the areas represent the invested total TX power.

The earliest event depicted at timepoint T1is a first TAU request TAU1sent by the user equipment1to the base station2. This is the regular operation for TAUs, indicating to the base station2after some (predefined) time that the user equipment is still in operation and still camping on the base station2.

The user equipment measures the TX power needed for carrying out the first TAU request and stores the value as first power value PV1.

After the TAU the user equipment1remains for some time in idle mode. This time has according to the 4G standard the duration T3324. In idle mode the user equipments listens to paging after an (e)DRX cycle and thus requires some more power after each DRX cycle for listening to paging in the DL.

At timepoint T2however the PSM mode is activated. The user equipment1is falling in a deep sleep mode, where not even paging messages are listened to. It is visible that during the PSM phase the power consumption is remarkably lower than during idle mode operation. In this time period the module may also shut down its main processor suspend its software and only perform clocking for awaking in time.

At any timepoint T3a data packet DP1is made available by the application. That is in particular a measurement result e.g. of current measurements, but any other—in particular regular—message could be meant by this. E.g. also IoT devices may sent regularly to the remote servers messages indicating the current operation status. If something is not operating well, any measures could be taken, e.g. sending a maintenance operator for resolving the issue.

In any case, the data packet is supposed to be sent to the remote server by the user equipment1, but his is not momentary data, but delay tolerant. That means, it does not have to be transmitted as soon as it is possible, in particular after the PSM phase has ended.

Consequently at timepoint T4the PSM phase ends, this is according to the standard governed by duration T3412. The first operation the user equipment after waking up is to carry out the next TAU request TAU2at timepoint T5.

Before sending the TAU the power ramps up, in particular for the RACH procedure preceding each TAU. But then the TAU itself is submitted.

Again the TX power needed for the second TAU TAU2is determined and stored as second power value PV2.

As it can be seen, the second TAU TAU2has a higher bar, than the first TAU. Consequently the first power value PV1is significantly lower than the second power value PV2.

As this difference exceeds the predetermined threshold value, it is consequently decided not to carry out the payload data transmission of the data packet DP1.

Consequently after the TAU only the idle phase is following, without any payload data transmission. At timepoint T6another PSM phase is started.

When this PSM phase has ended at timepoint T7, then again a TAU, now the third one is carried out.

The TX power needed for the third TAU TAU3is stored as the third power value PV3. This is again compared to the first power value PV1, which remained the reference power value due to the fact, that after the second TAU a delay was decided, meaning the second power value was found as being too high.

As it can be seen with the hatched bar, the third TAU needed less power than the second TAU. The reasons for that may be widespread. Preferably the path between antenna of the user equipment and the base station is disturbed. This can lead to a worse coverage enhancement situation with more repetitions, that obviously leads to a remarkable increase of TX power for sending the TAU request.

When comparing the third power value PV3with the first power value PV1, which is the reference power value, it can be seen, that there is almost no difference. Hence it is decided not to delay the payload data transmission.

Consequently in timepoint T9the transmission of data packet DP1is carried out. Also for this operation the power is indicated. Should this have been carried out after the second TAU, provided that the radio conditions have not changed since, then the hatched box would have been higher, but most probably take the same time. The square measure difference indicates, how much more time this data packet transmission would have had cost, if the data packet transmission were not delayed.

Alternatively the data packet DP1could have been submitted directly in conjunction with the TAU, which is foreseen as part of the Early Data Transmission (EDT) concept. This is in particular, but not only, the case when no delay is possible anymore due to that the delay tolerance value is reached. After transmission of the data packet DP1, the user equipment then again activates the PSM mode in timepoint T10. Currently not data packet is waiting. The third power value PV3now becomes the reference power value for the following TAUs. When the next data packet is supposed to be transmitted then the same procedure is applied.

In the above detailed description, reference is made to the accompanying drawings that show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that the various embodiments of the invention, although different, are not necessarily mutually exclusive. For example, a particular feature, structure, or characteristic described herein in connection with one embodiment may be implemented within other embodiments without departing from the scope of the invention. In addition, it is to be understood that the location or arrangement of individual elements within each disclosed embodiment may be modified without departing from the scope of the invention. The above detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims, appropriately interpreted, along with the full range of equivalents to which the claims are entitled.