TRANSMISSION BAND SELECTION USING BATTERY STATUS

Abstract

The present invention provides a method of selecting a frequency band of a mobile communications network in which a user equipment, UE, device is to operate, the method comprising determining a charge status of a rechargeable power supply of the UE device; and dependent on the charge status, generating an indication that the UE device should, taking into account the charge status, preferably be set to operate in a frequency band having a lower attenuation coefficient than a second frequency band in which the UE device could be set to operate in.

Claims

1. A method of selecting a frequency band of a mobile communications network in which a first user equipment, UE, device is to operate, the method comprising: determining a charge status of a rechargeable power supply of the first UE device; and dependent on the charge status, generating an indication that the first UE device should, taking into account the charge status, preferably be set to operate in a frequency band having a lower attenuation coefficient than a second frequency band in which the first UE device could be set to operate in.

2. The method according to claim 1, wherein the indication is generated only if operation in the second frequency band is not required in order for a required data transmission rate to be achieved.

3. The method according to claim 1, wherein the charge status is at least one of a remaining battery capacity, an indication that the power supply is being recharged, an indication that the first UE device is currently connected to an external power supply, an indication that the first UE device requires a power saving communication mode, and an indication that a communication at a data rate above a predetermined threshold is required.

4. The method according to claim 1, wherein the charge status is determined at a connection setup, periodically or in response to an occurrence of a predetermined event.

5. The method according to claim 1, wherein the indication is generated at a connection setup or following a change of charge status.

6. The method according to claim 1, wherein a selection of a frequency band in which the first UE device is to operate is performed by the mobile communications network in response to information received from the first UE device.

7. The method according to claim 1, wherein an attenuation coefficient for each possible frequency band is determined by the first UE device or by the mobile communications network.

8. A method of assigning a frequency band of a mobile communications network to a first user equipment, UE, device for communication with the network, the method comprising: receiving charge status information of a rechargeable power supply from the first UE device; and dependent on the charge status, assigning a frequency band having a lower attenuation coefficient than a second frequency band in which the first UE device could be set to operate in.

9. The method according to claim 8, wherein the charge status information is at least one of a remaining battery capacity, an indication that the power supply is being recharged, an indication that the first UE device is currently connected to an external power supply, an indication that the first UE device requires a power saving communication mode, and an indication that a communication at a data rate above a predetermined threshold is required.

10. The method according to claim 1, wherein following the generation of the indication, the first UE device transmits a message to one or more further UE devices to determine whether a frequency band with a lower attenuation coefficient currently being used by the one or more further UE devices could be made available for use by the first UE device.

11. The method according to claim 10, wherein a reconfiguration of the first UE device is performed by a base station following a notification that the one or more UE devices has agreed to the first UE device being assigned the frequency band with the lower attenuation coefficient.

12. The method according to claim 2, wherein the charge status is at least one of a remaining battery capacity, an indication that the power supply is being recharged, an indication that the first UE device is currently connected to an external power supply, an indication that the first UE device requires a power saving communication mode, and an indication that a communication at a data rate above a predetermined threshold is required.

13. The method according to claim 2, wherein the charge status is determined at a connection setup, periodically or in response to an occurrence of a predetermined event.

14. The method according to claim 2, wherein the indication is generated at a connection setup or following a change of charge status.

15. The method according to claim 2, wherein a selection of a frequency band in which the first UE device is to operate is performed by the mobile communications network in response to information received from the first UE device.

16. The method according to claim 2, wherein an attenuation coefficient for each possible frequency band is determined by the first UE device or by the mobile communications network.

17. The method according to claim 3, wherein the charge status is determined at a connection setup, periodically or in response to an occurrence of a predetermined event.

18. The method according to claim 3, wherein the indication is generated at a connection setup or following a change of charge status.

19. The method according to claim 3, wherein a selection of a frequency band in which the first UE device is to operate is performed by the mobile communications network in response to information received from the first UE device.

20. The method according to claim 3, wherein an attenuation coefficient for each possible frequency band is determined by the first UE device or by the mobile communications network.

Description

[0026] FIG. 1 shows steps performed in a first embodiment of the invention;

[0027] FIG. 2 shows steps performed in a second embodiment of the invention; and

[0028] FIG. 3 shows steps performed in a third embodiment of the invention.

[0029] In the following, a communication system according to 5G is assumed. This type of system is selected as example to show the principles of the invention. The invention is not limited to a specific communication system; such as 5G. All kinds of communication systems like UMTS, HSPA, LTE, LTE Advanced, WiFi or future radio communication systems can also benefit from the described methods.

[0030] In a first embodiment, a UE is performing the frequency selection. The message flow is depicted in FIG. 1 and described in the following:

[0031] Step 11: The UE wants to establish a connection towards the gNB of the mobile network, e.g. due to a mobile originated data transfer.

[0032] Step 12: The UE derives available carrier frequencies for transmission. Available carrier frequencies may be stored in the UE or transmitted from the mobile network e.g. during a connection establishment performed previously or now. The mobile network could transmit a list of carrier frequencies, or it may broadcast downlink pilot signals on available frequencies.

[0033] In this example the UE has scanned the downlink previously from the gNB, and has derived that three frequencies are available (cf. table 1) Step 13: The UE derives power information from its own power supply. This may include at least one of

[0034] whether the battery is charging

[0035] a battery charge level

[0036] a preference of the device relating to power consumptions (e.g. power saving mode or high data rate mode)

[0037] In this example, the device is running on battery and requires an ultra-low power consumption.

[0038] Step 14: The UE derives the frequency specific attenuation of available frequencies. In this example, it uses previously stored data with the average attenuation in 1 kilometer distance for each relevant frequency band. The values for the currently available bands from the gNB are shown in table 1.

TABLE-US-00001 TABLE 1 Attenuation of the available frequency bands. Available Average Attenuation Bands Frequency Range at 1 km distance Band 1 1.920-2.010 GHz 100 dB Band 2 24.24-27.50 GHz 120 dB Band 3 60-70 GHz 200 dB

[0039] Step 15: The UE selects one or more frequency bands according to the attenuation and the preference of the UE. In this example, the preferences require an ultra-low power consumption. Therefore, the UE selects band 1, as it has the lowest attenuation and therefore will require the lowest transmit power.

[0040] Step 16: The UE starts the transmission by using the selected frequency band.

[0041] In a further example, the UE derives available frequencies in step 12 from multiple gNBs. In this case, the UE will additionally consider the path loss for each gNB for the frequency selection. This is required, to obtain comparable values for the expected attenuations for different gNBs.

[0042] The UE will derive the path loss from the downlink signal of the respective gNB, derives the differences of the path loss with the average attenuation of the respective frequency from the stored data and adds this difference to the average attenuation of the available frequencies. This is done for each gNB in order to estimate the path loss for available frequencies. This piece of information is comparable between gNBs and can be used to select the frequency according to the path loss estimations and the power preferences.

[0043] This embodiment has the benefit that it enables the UE to save transmit power without any support by the network. This leads to a relatively simple implementation of the invention in commercial devices.

[0044] In a second embodiment, which is the preferred embodiment, frequency selection is performed by the mobile network. A flow chart is shown in FIG. 2 and described below.

[0045] Step 21: The UE wants to establish a connection towards the gNB of the mobile network, e.g. due to a mobile originated data transfer.

[0046] Step 22: The UE derives power information from its own power supply. In this example, the battery is currently charging. The service, that is requested by the user is an online gaming session, which will require highest data rate and lowest latency if battery status is above 50% or the battery is currently charging.

[0047] Step 23: The UE transmits a connection setup request to the gNB. The request includes the power information “charging” and the request for a high data rate at low latency.

[0048] Step 24: The gNB derives the available frequencies.

[0049] Step 25: The gNB derives the frequency specific signal attenuation. In this example, the available bands and the relating attenuations are listed in table 1.

[0050] Step 26: The gNB selects the frequencies for uplink and downlink transmissions. It prefers frequencies with a high available data rate. Band 3 from table 1 is selected, since band 3 provides high bandwidth with low interference.

[0051] Step 27: The selected frequency is assigned to UE by the serving gNB for connection establishment.

[0052] This embodiment has the benefit that it enables the network operator to assign frequency bands accordingly to power information from UEs. Therefore, mobile devices and mobile networks are more energy efficient. Idle and active time of mobile devices are extended. In addition, the mobile network can consider the current resource occupation, which leads to a fair and energy efficient distribution of the users to the available resources according to their needs and power conditions.

[0053] In a third embodiment, the UE negotiates the frequency bands with nearby other UEs. It may therefore use short range communication technologies like Bluetooth (r), WiFi, Zigbee etc., and the device-to-device communication of the cellular network (called sidelink or PC5 interface in LTE). Such negotiation may be performed prior or during a connection with the network. The flow chart for the negotiations is depicted in FIG. 3 and described below. For the sake of simplicity, only one uplink frequency band is negotiated. But the principle is also usable to negotiate multiple frequencies and multiple direction, e.g. uplink, downlink and sidelink:

[0054] Step 31: The UE's battery state falls below a threshold during an ongoing cellular connection. The currently used frequency band for uplink transmission F.sub.UL is not optimal for power saving and the UE is aware (e.g. from received downlink signals), that also power saving frequencies are provided by the cellular network.

[0055] Step 32: The UE transmits a request message via a short range technology (PC5 interface in this example) as broadcast transmission to nearby UEs. This request is for a change of the used uplink frequency F.sub.UL to an uplink frequency with a lower power requirement used by any nearby UE. Therefore the used uplink frequency and the currently assigned bandwidth BW are included in the request.

[0056] Step 33: Three neighboring UEs are currently available, N-UE 1 to N-UE 3. N-UE 1 is able and willing to swap frequencies, i.e. it currently uses a more power saving frequency band F.sub.UL,1 compared to F.sub.UL as used by the UE, and it will benefit from the swap, as the bandwidth offered by the UE (BW) is larger compared to the currently used bandwidth (BM). Therefore it accepts the swap by transmission of a frequency swap response message, which includes the uplink frequency and bandwidth as currently used by N-UE 1. Also N-UE 2 accepts the request and responds with F.sub.UL,2 and BW.sub.2. N-UE 3 has received the request, but is not willing or not able for the swap, e.g. because the offered bandwidth BW is not sufficient or it also requires a power saving uplink frequency. Therefore N-UE 3 does not send a response message. In this step, the respective users of the devices may be involved. E.g. the offer details are displayed and the users may accept or reject the offer.

[0057] Step 34: The UE selects the new UL frequency band from the received responses. The offer from N-UE 2 is not acceptable for the UE, e.g. as the bandwidth is too low. But the offer from N-UE 1 is acceptable.

[0058] Step 35: The UE accepts the offer from N-UE 1 by transmission of a frequency swap confirm message to N-UE 1.

[0059] Step 36: N-UE 1 inform the gNB about the reconfiguration by transmission of a reconfiguration request message to the gNB. Included are the new uplink frequency F.sub.UL and bandwidth BW.sub.1.

[0060] Step 37: The UE inform the gNB about the reconfiguration by transmission of a reconfiguration request message to the gNB. Included are the new uplink frequency F.sub.UL,1 and bandwidth BM.

[0061] Step 38: The gNB in this example reconfigure N-UE 1 and UE, i.e. it assigns F.sub.UL,1 and BM to UE and FUL and BW to N-UE 1. The gNB may also have the freedom to alter the proposed changes, e.g. to assign other frequencies or bandwidth than proposed, or to fully reject the reconfiguration requests.

[0062] From this embodiment, the connection of both UEs will benefit: the requesting UE will benefit from a reduced power consumption and the accepting UE will benefit from a higher bandwidth.