Technical Field

The present disclosure relates to a technique for providing system information (SI) of a radio access network (RAN) to one or more radio devices. More specifically, and without limitation, methods and devices are provided for receiving and transmitting SI.

Background

The Third Generation Partnership Project (3GPP) specifies radio access technologies such as Fourth Generation (4G) Long Term Evolution (LTE) and Fifth Generation (5G) New Radio (NR). System Information (SI) in NR comprises a Master Information Block (MIB) and a number of System Information Blocks (SIBs), which are divided into Minimum SI (MSI) and Other SI (OSI). The MSI comprises the MIB and a System Information Block 1 (SI Bl), which is also referred to as Remaining Minimum System Information (RMSI).

The MSI carries basic information required for initial access to a cell of a Radio Access Network (RAN) and for acquiring any OSI. For example, for a radio device (e.g., a UE) to be allowed to camp on a cell of the RAN, the radio device must have acquired the contents of the MSI from that cell.

The OSI comprises all SIBs not broadcast in the Minimum SI. The radio device does not need to receive these SIBs before accessing the cell. OSI is also referred to as on-demand SI because the cell (i.e., the gNB serving the cell) transmits or broadcasts these SIBs when explicitly requested by one or more radio devices. Compared to 4G, this 5G approach enhances Network Energy Saving (N ES) and reduces signaling overhead in the cell by transmitting OSI only when explicitly requested by radio devices, which for example implies the RAN can completely avoid transmitting OSI when there is no radio device in the cell.

Energy consumption of the RAN still increases for NR with respect to LTE due to more complex hardware (HW), e.g., more bandwidth (BW) and a greater number of antennas. This is particularly evident when the RAN uses NR in higher frequencies. Hence, it is important for the RAN to turn on and off unused HW modules during activity and inactivity times, respectively. For example, in frequency range 2 (FR2), an NR base station, i.e. a next generation Node B (gNB), can be configured with up to 64 beams and transmit up to 64 synchronization signal blocks (SSBs). This implies 64 ports with many transceiver chains involved. Such SSBs are transmitted every 20 ms in windows of 5 ms duration for the sake of providing coverage to potential UEs even if there actually are no UEs present in the cell. Another example of energy costly always-on broadcast transmissions is SIB1 which is typically transmitted per beam every 20 ms or 40 ms.

One basic method for saving energy at the RAN is to simply turn off a gNB or cell completely when it is determined or predicted that there is no traffic or even no radio device in the cell. For 3GPP Release 18 of NR, however, more elaborate schemes are required in which the gNB may be operational but in a reduced energy state. An example of such a reduced energy state includes gNBs transmitting the SSB (or a lighter version of the SSBs) or a Discovery Reference Signal (DRS) in various directions so that the radio devices can detect the presence of the RAN, but only transmit the RMSI (i.e., the SI Bl) when and/or where it makes sense. For example, the RMSI may be transmitted in beams where a radio device population is expected. In case one or more radio devices enter a beam in which the RMSI is not transmitted, the radio devices can ask, e.g. via a Wake-Up Signal (WUS), for transmission of the RMSI from the RAN.

The reduced energy schemes that are currently being discussed allow the gNB to avoid transmitting SIB1 in every single beam or cell until requested by the UEs. However, when a UE is in a beam or cell in which no SIB1 is transmitted, the UE might ask (e.g., transmit a WUS) for on-demand SIB1 provision even though the UE already has the same version of the SIB1 that was acquired earlier. Hence, upon absence of SIB1 in a beam or cell, since each of the UEs does not know whether the version it already has is up to date or not, the UEs keep transmitting on-demand requests for acquiring the latest version in vain as they already have that version.

Furthermore, the gNB may be transmitting SIB1 already in a neighbor beam, but as the UE typically is receiving data from the strongest beam, it will ask for SIB1 provision in its beam. This even though in many cases, the UE could be receiving SIB1 from the neighbor beam (e.g., second strongest beam with good enough quality). Summary

Accordingly, there is a need for a technique that improves providing system information of a radio access network to one or more radio devices.

According to a first method aspect, a method of receiving system information (SI) of a radio access network (RAN) at a radio device is provided. The method comprises or initiates receiving a discovery signal from the RAN. The discovery signal is indicative of at least one of a version of the SI of the RAN and an alternative radio resource for receiving the SI of the RAN. Furthermore, the method comprises or initiates receiving the SI from the RAN based on the indication in the discovery signal.

According to a first group of embodiments of the technique, the RAN may indicate to the radio device the currently valid version of the SI in the discovery signal. The discovery signal may be received before accessing (or without the need to access the RAN). At that early stage, the radio device may selectively transmit a request message for the receiving of the SI. In contrast, a conventional value tag may be included in System Information Block 1 (SI Bl), which requires completely decoding Minimum System Information (MSI).

Alternatively or in combination, according to a second group of embodiments, the RAN may indicate to the radio device an alternative radio resource (e.g., another beam other than a serving beam) for receiving the SI. The receiving of the SI using the alternative radio resource may or may not require transmitting a request message for the SI (also: on-demand SI) from the radio device to the RAN. The alternative radio resource may be an alternative to SIB1 resources conventionally indicated in a synchronization signal block (SSB), e.g., in a Master Information Block (MIB) of the SSB.

Any pair of embodiments from the two groups of embodiments may be combined. For example, the radio device may be camping on a cell of the RAN or may be connected (i.e., in a connected state) with a cell of the RAN, so that the radio device has already some version of the SI Bl, which may be updated based on (i.e., depending on) the indicated version and/or using the indicated alternative radio resource. The discovery signal being indicative of the version of the SI may mean that the discovery signal comprises an indication of the version of the SI. Herein, the "indicated version" may refer to the version of the SI according to the indication in the discovery signal.

The discovery signal being indicative of the alternative radio resource may mean that the discovery signal comprises an indication of the alternative radio resource for the receiving of the SI. Herein, the "indicated alternative radio resource" may refer to one or more radio resources (e.g., in a time domain, in a frequency domain and/or in a spatial domain, optionally by means of beamforming) and/or to the radio resource of the SI according to the indication in the discovery signal.

The indication in the discovery signal may refer to at least one of the indication of the version of the SI and the indication of the alternative radio resource. Herein, the expression "at least one of A, B and C" may refer to A and/or B and/or C, i.e. to A or B or C or any combination thereof.

The step of receiving the SI from the RAN based on the indication in the discovery signal may be implemented by selectively receiving the SI from the RAN, wherein the selection is based on the indication in the discovery signal.

The indicated alternative radio resource may be an alternative radio resource for the receiving of the SI according to the indicated version.

By indicating in the discovery signal at least one of the version of the SI of the RAN and the alternative radio resource for the receiving of the SI, at least some embodiments enable the radio device to determine if (e.g., whether or not) and/or where (e.g., on which radio resources) an updated version of the SI can be received or has to be received based on the indication in the discovery signal. This can reduce the number of request messages transmitted from the radio device to the RAN for requesting a transmission of the SI to the radio device, e.g., because the radio device determines based on the indicated version that it has already received the SI according to the indicated version and/or because the radio device receives SI according to the indicated version on an alternative radio resource (e.g., an alternative channel) from the RAN (optionally without a request message, e.g. because the SI is transmitted periodically on the alternative channel). Hence, in any one of these cases, a signaling overhead and/or an energy consumption at the radio device and/or an energy consumption at the RAN may be reduced. Since at least one of the indication of the version of the SI and the indication of the alternative radio resource is transmitted in the discovery signal, at least some embodiments enable the RAN to refrain from periodically transmitting the SI even though the SI (e.g., a minimum SI, optionally a Master Information Block, MIB, or a System Information Block 1, SI Bl) is required for camping on or accessing the RAN. Hence, embodiments can improve network energy savings (NES) and/or reduce signaling overhead. For example, the RAN may transmit the SI only upon receiving a request message or determining that at least one radio device is present. Herein, accessing the RAN may comprise performing a random access procedure with the RAN and/or establishing any radio resource control state (e.g., idle, inactive or connected) with the RAN.

The method may be performed by the radio device.

In an embodiment, the received discovery signal may be indicative of a currently valid version of the SI. Alternatively or in addition, the radio device may selectively receive the SI from the RAN based on whether or not the radio device has already received the indicated version of the SI, or the radio device receives the SI only if the indicated version is not available at the radio device.

The discovery signal may be indicative of the currently valid version of the SI, e.g., the version of the SI as currently applied by the RAN (e.g., by a base station serving the radio device). Alternatively or in addition, the indication may imply that all older or other versions of the SI are invalid.

In an embodiment, the method may further comprise or initiate comparing an available version of the SI that is available at the radio device with the indicated version. Alternatively or in addition, the method may further comprise or initiate a step of transmitting, to the RAN, a request message indicative of a request for the SI if the indicated version is not available at the radio device or if an available version of the SI that is available at the radio device is older than the indicated version or if a validity timer associated with the indication of the version has expired. The SI may be received responsive to the request message.

For example, the radio device may transmit, to the RAN, the request message indicative of the request for the SI only if the indicated version is not available at the radio device. The indicated version being not available may refer to no version of the SI being available at the radio device or the available SI being outdated compared to the indicated version. Alternatively or in addition to the step of comparing, the radio device may determine if the SI is receivable (e.g., decodable) at (or on) the alternative radio resource. The request message for the SI may be transmitted to the RAN if the SI is receivable at the indicated alternative radio resource.

In an embodiment, the discovery signal may be (or may comprise) a Synchronization Signal / Physical Broadcast Channel block (SSB) or a reduced SSB or a Discovery Reference Signal, DRS.

Herein, SSB may denote a Synchronization Signal/PBCH block, wherein PBCH denotes a Physical Broadcast Channel. The SSB may also be referred to as a synchronization signal block. The PBCH may carry a Master Information Block (MIB). The term SI as used herein may include the MIB or may exclude the MIB.

In an embodiment, the RAN may comprise at least one of a base station, a cell, and a radio beam. Alternatively or in addition, the discovery signal may be received from and/or the request message may be transmitted to a base station of the RAN. For example, the base station may be serving the radio device.

Alternatively or in addition, the discovery signal may be received from a cell of the RAN and/or the request message may be transmitted to a cell of the RAN. For example, the cell may be a serving cell of the radio device or the strongest cell at the radio device. Herein, "strongest" may refer to the strongest reference signal received power (RSRP) or reference signal received quality (RSRQ) or signal to noise ratio (SNR) or signal to interference and noise ratio (SINR).

Alternatively or in addition, the discovery signal may be received from a radio beam of the RAN (e.g., a receive beam) and/or the request message may be transmitted to a radio beam of the RAN (e.g., receive beam). For example, the radio beam may be the serving beam of the radio device or the strongest radio beam at the radio device.

The RAN, the base station, the cell, and/or the radio beam may use a radio frequency that is greater than 6 GHz or in the range of 24.25 GHz to 71.0 GHz.

In an embodiment, the indication of the alternative radio resource for the receiving of the SI may be indicative of an alternative radio resource that is different from radio resources on which the SI is receivable upon a request message or different from radio resources used for serving the at least one radio device. Alternatively or in addition, the indication of the alternative radio resource for the receiving of the SI may be indicative of an alternative base station for the receiving of the SI. For example, the alternative base station may be not a serving base station of the radio device or may be a neighboring base station for the radio device or a signal strength of the alternative base station may be not the greatest signal strength of base stations received at the radio device. Alternatively or in addition, the indication of the alternative radio resource for the receiving of the SI may be indicative of an alternative cell for the receiving of the SI. For example, the alternative cell may be not a serving cell of the radio device or may be not a cell on which the radio device camps or may be a neighboring cell for the radio device or a signal strength of the alternative cell may be not the greatest signal strength of cells received at the radio device. Alternatively or in addition, the indication of the alternative radio resource for the receiving of the SI may be indicative of an alternative radio beam for the receiving of the SI. For example, the alternative radio beam may be not a serving radio beam of the radio device or may be a neighboring radio beam for the radio device or a signal strength of the alternative radio beam may be not the greatest signal strength of radio beams received at the radio device.

Herein, the signal strength may be measured in terms of the RSRP or the RSRQ. or the SNR or the SINR or a combination thereof.

Herein, referring to the alternative radio resource may refer to at least one of the alternative base station, the alternative cell, and the alternative radio beam.

Receiving the SI from the RAN based on the indication in the discovery signal may mean that the SI is received from at least one of the alternative base station, the alternative cell, and the alternative radio beam.

In an embodiment, the SI may be receivable without request message and/or may be periodically receivable on at least one of the alternative radio resource, from the alternative base station, from the alternative cell, and/or in the alternative beam.

In an embodiment, the SI may be required for radio access to the RAN. For example, the SI may be required for a random access to the RAN. Alternatively or in addition, the method may further comprise or initiate a step of performing a random access to the RAN based on the transmitted (e.g., broadcast) SI of the RAN. The radio device may use the received SI for radio access to the base station of the RAN, in a cell of the RAN, on a beam of the RAN (optionally, using channel reciprocity for beamforming of a transmit beam to the RAN based on a receive beam from the RAN).

In an embodiment, the SI may be (or may comprise) one or more System Information Blocks (SIBs). Alternatively or in addition, the SI may be (or may comprise) a Minimum System Information (MSI). For example, the MSI may be the Minimum System Information that is required for accessing the RAN. Alternatively or in addition, the SI may be (or may comprise) a System Information Block 1 (SI Bl) or a Remaining Minimum System Information (RMSI). For example, the RMSI may be the Remaining Minimum System Information required for accessing the RAN other than a Master Information Block (MIB). Alternatively or in addition, the SI may be (or may comprise) Other System Information (OSI) other than a Minimum System Information (e.g. the above-mentioned MSI). For example, the OSI may be SI that is not required for accessing the RAN. Alternatively or in addition, the OSI may comprise at least one SIB _/ with j > 1.

In an embodiment, the SI may comprise different SIBs. The discovery signal may be indicative of a version of the respective SIB for each of the SIBs. For example, zero or at least one of the different SIBs may be received from the RAN based on the respective indication in the discovery signal.

In an embodiment, the SI may be not periodically receivable from the RAN. For example, the SI may be not periodically receivable from the serving base station or the serving cell or the serving beam. Alternatively or in addition, the SI may be receivable from the RAN only upon transmitting a request message to the RAN (e.g., the above-mentioned request message).

The RAN (e.g., the serving base station, the serving beam, the serving cell, and/or the serving beam) may refrains from broadcasting the SI.

In an embodiment, the discovery signal may be indicative of at least one of the indication of the version of the SI and the indication of the alternative radio resource while the SI is not broadcast from the RAN or a serving base station of the radio device (e.g., the above-mentioned serving base station) or a serving cell of the radio device (e.g., the above-mentioned serving cell) or a serving beam of the radio device (e.g., the above-mentioned serving beam). The discovery signal may be temporarily indicative of at least one of the indication of the version of the SI and the indication of the alternative radio resource, e.g., only while the SI is not broadcast from the RAN or the serving base station or the serving cell or the serving beam.

In an embodiment, the discovery signal may be received from the RAN (e.g., from the serving base station) in one direction or swept in different directions, in one beam or swept in different beams, and/or in one or more cells.

In an embodiment, the indication of the version of the SI may be (or may comprise) a value tag, a version tag, or a hash value of the SI.

In an embodiment, at least one of the indication of the version of the SI and the indication of the alternative radio resource in the discovery signal may be received multiple times (e.g., periodically). At least one of the indication of the version of the SI and the indication of the alternative radio resource may be updated when the SI receivable from the RAN changes.

In an embodiment, at least one of the indication of the version of the SI and the indication of the alternative radio resource may be included in bits associated with the discover signal. Alternatively or in addition, the discovery signal (e.g., the SSB) may comprise the MIB including at least one of the indication of the version of the SI and the indication of the alternative radio resource.

In an embodiment, one or more bits of the MIB may be repurposed to carry at least one of the indication of the version of the SI and the indication of the alternative radio resource. For example, one or more bits of the MIB may be repurposed to carry at least one of the indications while the SI is not broadcast from the RAN or the serving base station or the serving cell or the serving beam. Alternatively or in addition, the one or more bits of the MIB may be temporarily repurposed (e.g., associated with another technical meaning).

In an embodiment, the discovery signal may comprise a signal sequence, optionally at least one of a primary synchronization signal (PSS) a secondary synchronization signal (SSS) and a Zadoff-Chu sequence. Alternatively or in addition, one or more parameters of the signal sequence may be indicative of at least one of the indication of the version of the SI and the indication of the alternative radio resource, optionally. The one or more parameters may comprise at least one of a time position of the signal sequence, a frequency position of the signal sequence, and a signature of the signal sequence.

In an embodiment, the radio device may store the indicated version associated to the SI.

In an embodiment, in case the indicated version differs from the stored version and the SI is currently not transmitted in a current beam from the RAN to the radio device, the radio device may transmit a request message for on-demand provision of the SI, optionally in the current beam or direction or cell.

According to a second method aspect, a method of transmitting system information (SI) from a radio access network (RAN) to at least one radio device is provided. The method comprises or initiates transmitting a discovery signal from the RAN, the discovery signal may be indicative of at least one of a version of the SI of the RAN and an alternative radio resource for receiving the SI of the RAN. Alternatively or in addition, the method comprises or initiates transmitting, optionally broadcasting, the SI to the at least one radio device according to the indication in the discovery signal.

The transmitting of the discovery signal from the RAN may comprise broadcasting or beam sweeping the discovery signal from the RAN.

The transmitting of the SI to the at least one radio device according to the indication in the discovery signal may comprise broadcasting the SI to the at least one radio device according to the indication in the discovery signal.

The method may be performed by a base station of the RAN, e.g., a base station serving the radio device. The discovery signal may be transmitted in a first cell of the base station (e.g., the serving cell of the radio device), and the SI may be transmitted in the first cell or (e.g., according to the alternative radio resource) in a second cell of the base station. Alternatively or in addition, the step of transmitting the discovery signal may be performed by a first base station of the RAN and the step of transmitting the SI may be performed by a second base station of the RAN.

In an embodiment, the transmitted discovery signal may be indicative of a currently valid version of the SI. Alternatively or in addition, the RAN may refrain from transmitting, optionally refrain from broadcasting, the SI in radio resources used for serving the at least one radio device. Alternatively or in addition, the RAN may transmit, optionally broadcast, the SI to the at least one radio device. In an embodiment, the method may further comprise or initiate determining a data traffic or a population of the at least one radio device using radio resources for serving the at least one radio device. The RAN may refrain from transmitting, optionally refrain from broadcasting, the SI in radio resources used for serving the at least one radio device if the data traffic volume or the population is less than a predefined threshold. Alternatively or in addition, further may comprise or initiating receiving, from the at least one radio device, a request message indicative of a request for the SI. The RAN may transmit, optionally broadcast, the SI in radio resources used for serving the at least one radio device responsive to the request message.

In an embodiment, the discovery signal may be (or may comprise) a Synchronization Signal / Physical Broadcast Channel block (SSB) or a reduced SSB or a Discovery Reference Signal, DRS.

In an embodiment, the RAN may comprise, and/or the discovery signal is transmitted from, and/or the request message is received at, a base station of the RAN. For example, the base station may be serving the at least one radio device. Alternatively or in addition, the RAN may comprise, and/or the discovery signal is transmitted from, and/or the request message may be received at, a cell of the RAN. For example, the cell may be a serving cell of the radio device or the strongest cell at the radio device. Alternatively or in addition, the RAN may comprise, and/or the discovery signal is transmitted from, and/or the request message is received at, a radio beam of the RAN. For example, the radio beam may be a serving beam of the radio device or the strongest radio beam at the radio device.

In an embodiment, the indication of the alternative radio resource for the receiving of the SI may be indicative of an alternative radio resource that is different from radio resources on which the SI is receivable upon a request message or different from radio resources used for serving the at least one radio device. Alternatively or in addition, the indication of the alternative radio resource for the receiving of the SI may be indicative of an alternative base station for the transmitting of the SI. For example, the alternative base station may be not a serving base station of the radio device or a neighboring base station of a serving base station of the radio device or a signal strength of the alternative base station may be not the greatest signal strength of base stations reported by the radio device. Alternatively or in addition, the indication of the alternative radio resource for the receiving of the SI may be indicative of an alternative cell for the transmitting of the SI. For example, the alternative cell may be not a serving cell of the radio device or may be not a cell on which the radio device camps or is a neighboring cell of a serving cell of the radio device or a signal strength of the alternative cell may be not the greatest signal strength of cells reported by the radio device. Alternatively or in addition, the indication of the alternative radio resource for the receiving of the SI may be indicative of an alternative radio beam for the transmitting of the SI. For example, the alternative radio beam may be not a serving radio beam of the radio device or may be a neighboring radio beam of a serving radio beam of the radio device or a signal strength of the alternative radio beam may be not the greatest signal strength of radio beams reported by the radio device.

In an embodiment, the SI may be transmitted, optionally broadcast, without request message and/or is periodically transmitted, optionally broadcast, on at least one of the alternative radio resource, from the alternative base station, in the alternative cell, and/or in the alternative beam.

In an embodiment, the SI may be required for radio access to the RAN, optionally for a random access to the RAN. Alternatively or in addition, the method further may comprise or initiate a step of receiving a random access from the at least one radio device at the RAN based on the transmitted (e.g., broadcast) SI of the RAN.

In an embodiment, the SI may be (or may comprise) one or more System Information Blocks (SIBs). Alternatively or in addition, the SI may be (or may comprise) a Minimum System Information (MSI), optionally the MSI that is required for accessing the RAN. Alternatively or in addition, the SI may be or comprises a System Information Block 1 (SI Bl) or a Remaining Minimum System Information (RMSI), optionally a RMSI required for accessing the RAN other than a Master Information Block (MIB). Alternatively or in addition, the SI may be (or may comprise) Other System Information (OSI) other than a (e.g., the above) MSI, optionally SI that is not required for accessing the RAN or least one SIB _/ with j > 1.

In an embodiment, the SI may comprise different SIBs and the discovery signal may be indicative of a version of the respective SIB for each of the SIBs. For example, zero or at least one of the different SIBs may be received from the RAN based on the respective indication in the discovery signal. In an embodiment, the SI may be not periodically transmitted (e.g., not periodically broadcast) from the RAN, optionally from the serving base station or the serving cell or the serving beam. Alternatively or in addition, the SI may be transmitted, optionally broadcast, from the RAN only upon receiving a (e.g., the above-mentioned) request message at the RAN.

In an embodiment, the discovery signal may be indicative of at least one of the indication of the version of the SI and the indication of the alternative radio resource while the SI is not transmitted, optionally broadcast, from the RAN or from a or the base station serving the radio device or from a cell (e.g., above- mentioned cell) serving the radio device or from a beam (e.g., the above- mentioned beam) serving the radio device.

In an embodiment, the discovery signal may be transmitted from the RAN, optionally from the base station serving the at least one radio device, in one direction or swept in different directions, in one beam or swept in different beams, and/or in one or more cells.

In an embodiment, the indication of the version of the SI may be or comprises a value tag, a version tag, or a hash value of the SI.

In an embodiment, at least one of the indication of the version of the SI and the indication of the alternative radio resource in the discovery signal may be transmitted multiple times, optionally periodically, and. At least one of the indication of the version of the SI and the indication of the alternative radio resource may be updated when the SI of the RAN changes.

In an embodiment, at least one of the indication of the version of the SI and the indication of the alternative radio resource may be included in bits associated with the discover signal. Alternatively or in addition, the discovery signal, optionally a (e.g. the above) SSB, may comprise an (e.g., the above) MIB including at least one of the indication of the version of the SI and the indication of the alternative radio resource.

In an embodiment, one or more bits of the MIB may be repurposed to carry at least one of the indication of the version of the SI and the indication of the alternative radio resource, optionally while the SI is not transmitted (e.g., not broadcast) from the RAN or from the base station serving the at least one radio device or from the cell serving the at least one radio device or from the beam serving the at least one radio device.

In an embodiment, the discovery signal may comprise a signal sequence, optionally at least one of a primary synchronization signal (PSS) a secondary synchronization signal (SSS) and a Zadoff-Chu sequence. Alternatively or in addition, one or more parameters of the signal sequence may be indicative of at least one of the indication of the version of the SI and the indication of the alternative radio resource, optionally. The one or more parameters may comprise at least one of a time position of the signal sequence, a frequency position of the signal sequence, and a signature of the signal sequence.

In an embodiment, the transmission of the SI may trigger the radio device to store the indicated version associated to the SI.

In an embodiment, in case the indicated version may differ from the stored version and the SI is currently not transmitted in a current beam from the RAN to the radio device, a request message for on-demand provision of the SI is received from the radio device, optionally in the current beam or direction or cell.

The second method aspect may further comprise any feature and/or any step disclosed in the context of the first method aspect, or a feature and/or step corresponding thereto, e.g., a receiver counterpart to a transmitter feature or step. Alternatively or in addition, the first method aspect may further comprise any feature and/or any step disclosed in the context of the second method aspect, or a feature and/or step corresponding thereto.

Without limitation, for example in a 3GPP implementation, any "radio device" may be a user equipment (UE). Alternatively or in addition, without limitation, for example in a 3GPP implementation, any base station may be network node, e.g. a gNB.

The technique may be applied in the context of 3GPP New Radio (NR). Unlike 3GPP LTE, an effect in terms of NES may be greater for NR due to a greater number of radio chains that can be temporarily switched off and/or more frequent changes in the SI that can be handled according to the subject technique. Herein, the "SI" in the context of any embodiment of the technique may be subset of total system information of the RAN, e.g., a certain subset (e.g., a certain system information block, SIB) of the system information specified (e.g., by 3GPP) for the radio access technology (e.g., NR) used by the RAN.

The technique may be implemented in accordance with a 3GPP specification, e.g., for 3GPP release 17 or 18. The technique may be implemented for 3GPP LTE according to a modification of the 3GPP document 3GPP TS 36.331, version 17.2.0 and/or for 3GPP NR according to a modification of the 3GPP document 3GPP TS 38.331, version 17.2.0.

The radio device and the RAN may be wirelessly connected in an uplink (UL) and/or a downlink (DL) through a Uu interface.

The radio device and/or the RAN may form, or may be part of, a radio network, e.g., according to the Third Generation Partnership Project (3GPP) or according to the standard family IEEE 802.11 (Wi-Fi). The first method aspect and the second method aspect may be performed by one or more embodiments of the radio device and the RAN (e.g., a base station), respectively.

The RAN may comprise one or more base stations, e.g., performing the second method aspect. Alternatively or in addition, the radio network may be a vehicular, ad hoc and/or mesh network comprising two or more radio devices, e.g., acting as a remote radio device and/or a relay radio device according to the first and second method aspects, respectively.

Any of the radio devices may be a 3GPP user equipment (UE) or a Wi-Fi station (STA). The radio device may be a mobile or portable station, a device for machinetype communication (MTC), a device for narrowband Internet of Things (NB-loT) or a combination thereof. Examples for the UE and the mobile station include a mobile phone, a tablet computer and a self-driving vehicle. Examples for the portable station include a laptop computer and a television set. Examples for the MTC device or the NB-loT device include robots, sensors and/or actuators, e.g., in manufacturing, automotive communication and home automation. The MTC device or the NB-loT device may be implemented in a manufacturing plant, household appliances and consumer electronics. Whenever referring to the RAN, the RAN may be implemented by one or more base stations.

The base station may encompass any station that is configured to provide radio access to any of the radio devices. The base stations may also be referred to as a beam, a cell, a transmission and reception point (TRP), radio access node or access point (AP). The base station and/or the relay radio device may provide a data link to a host computer providing the user data to the remote radio device or gathering user data from the remote radio device. Examples for the base stations may include a 3G base station or Node B (NB), 4G base station or eNodeB (eNB), a 5G base station or gNodeB (gNB), a Wi-Fi AP, and a network controller (e.g., according to Bluetooth, ZigBee or Z-Wave).

The RAN may be implemented according to the Global System for Mobile Communications (GSM), the Universal Mobile Telecommunications System (UMTS), 3GPP Long Term Evolution (LTE) and/or 3GPP New Radio (NR).

Any aspect of the technique may be implemented on a Physical Layer (PHY), a Medium Access Control (MAC) layer, a Radio Link Control (RLC) layer, a packet data convergence protocol (PDCP) layer, and/or a Radio Resource Control (RRC) layer of a protocol stack for the radio communication.

Herein, referring to a protocol of a layer may also refer to the corresponding layer in the protocol stack. Vice versa, referring to a layer of the protocol stack may also refer to the corresponding protocol of the layer. Any protocol may be implemented by a corresponding method.

As to another aspect, a computer program product is provided. The computer program product comprises program code portions for performing any one of the steps of the method aspect disclosed herein when the computer program product is executed by one or more computing devices. The computer program product may be stored on a computer-readable recording medium. The computer program product may also be provided for download, e.g., via the radio network, the RAN, the Internet and/or the host computer. Alternatively, or in addition, the method may be encoded in a Field-Programmable Gate Array (FPGA) and/or an Application-Specific Integrated Circuit (ASIC), or the functionality may be provided for download by means of a hardware description language. As to a first device aspect, a device (e.g., a radio device or UE) according is provided for receiving system information (SI) of a radio access network (RAN) at the radio device. The device comprises memory operable to store instructions and processing circuitry operable to execute the instructions, such that the radio device is operable to receive a discovery signal from the RAN. The discovery signal is indicative of at least one of a version of the SI of the RAN and an alternative radio resource for receiving the SI of the RAN. Alternatively or in addition, the device is operable to receive the SI from the RAN based on the indication in the discovery signal.

According to another first device aspect, a radio device for receiving system information (SI) of a radio access network (RAN) at the radio device is provided. The radio device is configured to perform the first method aspect.

According to still another first device aspect, a user equipment (UE) configured to communicate with a base station or with a radio device functioning as a gateway is provided. The UE comprises a radio interface and processing circuitry configured to receive a discovery signal from the RAN. The discovery signal is indicative of at least one of a version of the SI of the RAN and an alternative radio resource for receiving the SI of the RAN. Alternatively or in addition, the device is configured to receive the SI from the RAN based on the indication in the discovery signal.

Any of the first device aspects may further comprise any feature or step of the first method aspect.

According to a second device aspect, a base station for transmitting system information (SI) from a radio access network (RAN) to at least one radio device is provided. The base station comprises memory operable to store instructions and processing circuitry operable to execute the instructions, such that the base station is operable to transmit (e.g., broadcasting or beam sweeping) a discovery signal from the RAN. The discovery signal is indicative of at least one of a version of the SI of the RAN and an alternative radio resource for receiving the SI of the RAN. Alternatively or in addition, the base station may be operative to transmit (e.g., broadcasting) the SI to the at least one radio device according to the indication in the discovery signal. According to another second device aspect, a base station for transmitting system information (SI) from a radio access network (RAN) to at least one radio device is provided. The base station is configured to transmit (e.g., broadcast or beam sweep) a discovery signal from the RAN. The discovery signal may be indicative of at least one of a version of the SI of the RAN and an alternative radio resource for receiving the SI of the RAN. Alternatively or in addition, the base station is configured to transmit (e.g., optionally broadcast) the SI to the at least one radio device according to the indication in the discovery signal.

According to a still further second device aspect, a base station configured to communicate with a user equipment (UE) is provided. The base station comprises a radio interface and processing circuitry configured to transmit (e.g., optionally broadcast or beam sweep) a discovery signal from the RAN, the discovery signal being indicative of at least one of a version of the SI of the RAN and an alternative radio resource for receiving the SI of the RAN. Alternatively or in addition, the base station may be configured to transmit (e.g., broadcasting) the SI to the at least one radio device according to the indication in the discovery signal.

As to a still further aspect, a communication system including a host computer is provided. The host computer comprises a processing circuitry configured to provide user data. The host computer further comprises a communication interface configured to forward the first and/or second data to a cellular network (e.g., the RAN and/or the base station) for transmission to a UE. A processing circuitry of the cellular network is configured to execute any one of the steps of the first and/or second method aspects. The UE comprises a radio interface and processing circuitry, which is configured to execute any one of the steps of the first and/or second method aspects.

The communication system may further include the UE. Alternatively, or in addition, the cellular network may further include one or more base stations configured for radio communication with the UE and/or to provide a data link between the UE and the host computer using the first and/or second method aspects.

The processing circuitry of the host computer may be configured to execute a host application, thereby providing the first and/or second data and/or any host computer functionality described herein. Alternatively, or in addition, the processing circuitry of the UE may be configured to execute a client application associated with the host application.

Any one of the devices, the UE, the base station, the communication system or any node or station for embodying the technique may further include any feature disclosed in the context of the method aspect, and vice versa. Particularly, any one of the units and modules disclosed herein may be configured to perform or initiate one or more of the steps of the method aspect.

Brief Description of the Drawings

Further details of embodiments of the technique are described with reference to the enclosed drawings, wherein:

Fig. 1 shows a schematic block diagram of an embodiment of a device for receiving system information (SI) of a radio access network (RAN) at a radio device;

Fig. 2 shows a schematic block diagram of an embodiment of a device for transmitting system information (SI) of a radio access network (RAN) to at least one radio device;

Fig. 3 shows a flowchart for a method of receiving system information (SI) of a radio access network (RAN) at a radio device, which method may be implementable by the device of Fig. 1;

Fig. 4 shows a flowchart for a method of transmitting system information (SI) of a radio access network (RAN) to at least one radio device, which method may be implementable by the device of Fig. 2;

Fig. 5 schematically illustrates an example of a radio network comprising embodiments of the devices of Figs. 1 and 2 for performing the methods of Figs. 3 and 4, respectively;

Fig. 6 schematically illustrates a signaling diagram resulting from a first group of embodiments of the devices of Figs. 1 and 2 performing the methods of Figs. 3 and 4, respectively, in radio communication; Fig. 7 schematically illustrates a signaling diagram resulting from a second group of embodiments of the devices of Figs. 1 and 2 performing the methods of Figs. 3 and 4, respectively, in radio communication;

Fig. 8 shows a schematic block diagram of a radio device embodying the device of Fig. 1;

Fig. 9 shows a schematic block diagram of a base station embodying the device of Fig. 2;

Fig. 10 schematically illustrates an example telecommunication network connected via an intermediate network to a host computer;

Fig. 11 shows a generalized block diagram of a host computer communicating via a base station or radio device functioning as a gateway with a user equipment over a partially wireless connection; and

Figs. 12 and 13 show flowcharts for methods implemented in a communication system including a host computer, a base station or radio device functioning as a gateway and a user equipment.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as a specific network environment in order to provide a thorough understanding of the technique disclosed herein. It will be apparent to one skilled in the art that the technique may be practiced in other embodiments that depart from these specific details. Moreover, while the following embodiments are primarily described for a New Radio (NR) or 5G implementation, it is readily apparent that the technique described herein may also be implemented for any other radio communication technique, including a Wireless Local Area Network (WLAN) implementation according to the standard family IEEE 802.11, 3GPP LTE (e.g., LTE-Advanced or a related radio access technique such as MulteFire), for Bluetooth according to the Bluetooth Special Interest Group (SIG), particularly Bluetooth Low Energy, Bluetooth Mesh Networking and Bluetooth broadcasting, for Z-Wave according to the Z-Wave Alliance or for ZigBee based on IEEE 802.15.4.

Moreover, those skilled in the art will appreciate that the functions, steps, units and modules explained herein may be implemented using software functioning in conjunction with a programmed microprocessor, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a Digital Signal Processor (DSP) or a general purpose computer, e.g., including an Advanced RISC Machine (ARM). It will also be appreciated that, while the following embodiments are primarily described in context with methods and devices, the invention may also be embodied in a computer program product as well as in a system comprising at least one computer processor and memory coupled to the at least one processor, wherein the memory is encoded with one or more programs that may perform the functions and steps or implement the units and modules disclosed herein.

Fig. 1 schematically illustrates a block diagram of an embodiment of a device for receiving system information (SI) of a radio access network (RAN). The device is generically referred to by reference sign 100.

The device 100 comprises a discovery signal reception module 102 that receives a discovery signal from the RAN, the discovery signal being indicative of at least one of

- a version of the SI of the RAN and

- an alternative radio resource for receiving the SI of the RAN.

The device 100 further comprises an SI reception module 108 that receives the SI from the RAN based on the indication in the discovery signal.

Optionally, the device 100 comprises a version comparison module 104 that compares an available version of the SI that is available at the radio device with the indicated version and/or with a validity timer associated with the indicated version.

Further optionally, the device 100 comprises a request transmission module 106 that transmits, to the RAN, a request message indicative of a request for the SI if the indicated version is not available at the radio device or if an available version of the SI that is available at the radio device is older than the indicated version or if the validity time has expired. The SI is received responsive to the request message.

Any of the modules of the device 100 may be implemented by units configured to provide the corresponding functionality.

The device 100 may also be referred to as, or may be embodied by, the radio device (or briefly: UE). The radio device 100 and the RAN (e.g., one or more base stations of the RAN) may be in direct radio communication, e.g., at least for receiving discovery signal and/or the SI from the RAN 500. The base station may be embodied by the below device 200.

Fig. 2 schematically illustrates a block diagram of an embodiment of a device for transmitting system information (SI) from a radio access network (RAN) to at least one radio device. The device is generically referred to by reference sign 200.

The device 200 comprises a discovery signal transmission module 202 for transmitting, optionally broadcasting or beam sweeping, a discovery signal from the RAN. The discovery signal is indicative of at least one of a version of the SI of the RAN and an alternative radio resource for receiving the SI of the RAN.

The device 200 further comprises an SI transmission module 208 that transmits, optionally broadcasts, the SI to the at least one radio device according to the indication in the discovery signal.

Optionally, the device 200 comprises a request reception module 206 that receives, from the at least one radio device, a request message indicative of a request for the SI. The RAN transmits, optionally broadcasts, the SI in radio resources used for serving the at least one radio device responsive to the request message.

Any of the modules of the device 200 may be implemented by units configured to provide the corresponding functionality.

The device 200 may also be referred to as, or may be embodied by, the base station or multiple base stations (or briefly: gNB). The base station 200 and the at least one radio device may be in direct radio communication, e.g., at least for the transmission of the discovery signal and/or the SI. The radio device may be embodied by the above device 100.

Fig. 3 shows an example flowchart for a method 300 of performing the first method aspect. The method comprises the steps indicated in the Fig. 3 or any one of the first method aspect.

The method 300 may be performed by the device 100. For example, the modules 102, 104, 106, and 108 may perform the steps 302, 304, 306, and 308, respectively.

Fig. 4 shows an example flowchart for a method 400 of performing the second method aspect. The method 400 comprises the steps indicated in the Fig. 4 or any one of the second method aspect.

The method 400 may be performed by the device 200 (e.g., one or more base stations of the RAN). For example, the modules 202, 206, and 208 may perform the steps 402, 406, and 408, respectively.

In any aspect, the technique may be applied to uplink (UL), downlink (DL) or direct communications between radio devices, e.g., device-to-device (D2D) communications or sidelink (SL) communications.

Each embodiment of the device 100 and device 200 may be a radio device or a base station. Herein, any radio device may be a mobile or portable station and/or any radio device wirelessly connectable to a base station or RAN, or to another radio device. For example, the radio device may be a user equipment (UE), a device for machine-type communication (MTC) or a device for (e.g., narrowband) Internet of Things (loT). Two or more radio devices may be configured to wirelessly connect to each other, e.g., in an ad hoc radio network or via a 3GPP SL connection. Furthermore, any base station may be a station providing radio access, may be part of a radio access network (RAN) and/or may be a node connected to the RAN for controlling the radio access. For example, the base station may be an access point, for example a Wi-Fi access point. Fig. 5 schematically illustrates an example of a radio network comprising embodiments of the radio device 100 and at least one base station 200 for performing the methods 300 and 400, respectively, in a RAN 500.

Examples of the radio resources used for serving the radio device 100 include a serving cell 201A of the base station 200 and/or a serving beam 201B of the base station 200 (e.g., in the serving cell 201A).

Fig. 6 schematically illustrates a signaling diagram resulting from a first group of embodiments of the radio device 100 and a base station 200 performing the methods 300 and 400, respectively, in radio communication. In the first group of embodiments, the radio resources used for transmitting 408 the SI upon request 306 may be the same radio resources (e.g., serving cell and/or serving beam) used for serving the radio device 100.

Fig. 7 schematically illustrates a signaling diagram resulting from a second group of embodiments of the radio device 100 and a base station 200 performing the methods 300 and 400, respectively, in radio communication. In the second group of embodiments, the radio resources used for transmitting 408 the SI (optionally upon request) may be the alternative radio resources (e.g., not the serving cell and/or not the serving beam used for serving the radio device 100).

The technique may be implemented as a method 300 of indicating to a radio device 100 (e.g., a UE) whether the radio device 100 needs to request (e.g., ask) for transmission of System Information Block 1 (SI Bl, i.e., RMSI) and/or Other System Information (OSI).

At least some embodiments enable a radio device 100 (e.g., a UE) to know whether the version of the SI the respective radio device already has is up to date or not, so that the radio device 100 does not keep transmitting 306 on-demand requests (i.e., request messages) for acquiring the latest version of the SI in vain as the radio device 100 already has the latest version of the SI.

Radio device embodiments 100 of the technique may receive an indication (e.g., a value tag) of the currently valid version of SI (e.g., for a certain SIB, optionally RMSI and/or OSI). The indication may be included in a discovery signal broadcast by a base station 200 (e.g., a gNB) in an energy-saving state. Since the indication is not included in the RMSI (i.e., SI Bl), e.g. in contrast to an existing value tag for OSI, the radio device 100 can refrain from requesting a transmission of a version of the SI that is already available at the radio device.

Examples of the discovery signal include SSB and DRS.

A base station 100 (e.g., gNBs) may sweep 402 a discovery signal (e.g., a SSB or a lightweight SSB or a DRS) in one or more directions (e.g. one or more beams and/or one or more cells). For network energy savings (NES), the base station 200 may refrain from transmitting 402 SI (e.g., RMSI, i.e., SI Bl, and/or OSI) in the one or more directions and/or the one or more beams and/or the one or more cells, or may sweep 402 the SI (e.g., the RMSI and/or the OSI) only in a subset of the one or more directions and/or the one or more beams and/or the one or more cells associated with the discovery signal (e.g., the SSB or other SSB-like signals). Radio devices 100 (e.g., UEs) may request for SI (e.g., the RMSI and/or the OSI) on- demand by transmitting 306 a request message, e.g., a Wake-Up Signal (WUS) or alike.

Base station embodiments 200 of the technique provide 402 an indication (e.g., a value tag or version tag, optionally a hash value of the SI) as part of a discovery signal (e.g., SSB or SSB-like signal or DRS). The indication (e.g., the version tag) to the one or more radio devices is indicative of the version of the SI (e.g., the version of SIB1 and/or OSI) that is currently relevant (e.g., for the base station or the RAN or the system comprising the base station and the radio device). In case the radio device 100 already has acquired this version, the radio device 100 needs not to transmit 306 an on-demand request. Only if the radio device 100 has no version of the SI (e.g., SIB1 and/or OSI), or an older version of the SI, the radio device 100 needs to ask 306 for the latest version.

When the RAN 500 (e.g., the base station 200) updates the SI (e.g., the SIB1 and/or the OSI), the RAN (e.g., the base station) also updates the indication (e.g., the version tag) transmitted 402 in discovery signal (e.g., in the SSB).

In any embodiment, the discovery signal (e.g., the SSB) may further comprise an indication (or indicator) for one or more other beams and/or one or more other cells (which may be collectively referred to as alternative radio resources) in which the current version of the SI (e.g., the SIB1 and/or OSI) is transmitted 402. If a radio device 100 (e.g., a UE) has good radio connection to more than one beam or cel I, and is interested in acquiring the current version of the SI (e.g., the SIB1 and/or the OS I), and the currently strongest beam or cell of the radio device 100 (or the beam or cell to which the radio device is associated) is not transmitting 402 the current version of the SI (e.g., the SIB1 and/or the OSI ), but another beam or cell (i.e., the alternative radio resource) is transmitting the current version of the SI (e.g., the SIB1 and/or the OSI), the radio device 100 may, based on the indication (or indicator), acquire the current version of the SI (e.g., the SIB1 and/or the OSI) from the other beam or cell, e.g. while being radio-connected to the strongest beam or cell (or the beam or cell to which the radio device is associated).

The indication in the discovery signal may be implemented using at least one of the features (e.g., a data structure) specified for a SI value tag (e.g. an integer value "valueTag") in the 3GPP specification for LTE (e.g., in clause 5.2.1.3 of 3GPP document TS 36.311, version 17.2.0) or the 3GPP specification for NR (e.g., in clause 5.2.2.2 of 3GPP document TS 38.311, version 17.2.0). Preferably, the indication (e.g., the SI value tag) is not broadcast as part of the SIB scheduling information inside SIB1 (e.g., for most of the SIBs while some SIBs are exempt). The indication (e.g., the value tag) transmitted from the RAN 500 (e.g., the base station) to the radio devices (e.g., UEs) may be indicative, not only if the contents of a certain SIB has changed, but which version of a certain SIB (e.g., SI Bl) is currently valid, so that the UEs 100 is enabled to selectively reacquire the respective SIB depending on the indication.

Preferably, the discovery signal is not indicative of any SI or at least not the SI for which the currently valid version is indicated.

Alternatively or in addition, to the listed embodiments, the following aspects are disclosed.

Without limitation, the indication of the version is also referred to as a version tag. Alternatively or in addition, without limitation, the radio device is also referred to as UE. Alternatively or in addition, without limitation, the base station is also referred to as gNB.

A first group of method embodiments 400 in a network (e.g., the RAN 500) is provided, through which the RAN 500 provides one or more version tags for broadcast information transmission (e.g., SIB1 and/or OSI) in the discovery signal (e.g., SSB or SSB-alike, or other discovery signals, DRS) or a neighbor cell SIB1 and/or OSI.

Said version tag may be used to provide UEs 100 about the version of the currently relevant SIB1 and/or OSI.

Said version tag may be updated when the broadcast contents (e.g., the part of the system information referred to as SI) are updated.

Said version tag may be provided in SSB's MIB, or in bits associated with an SSB- like signal or other discover signals.

Some bits of the MIB may be repurposed to carry the version tag while the broadcast information (or parts thereof) is currently not provided in the current beam.

The discovery signal (e.g., a reference signal such as SSB) characteristics' may be indicative of the version tag.

Some bits of a neighbor cell SIB1 or cell may be used to convey the version tag of SSB1/OSI of the serving cell.

A second group of method embodiments 400 in a network (e.g., the RAN 500) is provided, through which the RAN 500 provides one or more alternative radio resources, e.g. neighbor beam and/or directions and/or cell information, in which broadcast information for receiving the SI (e.g., SIB1 and/or OSI) is transmitted, e.g. when the current beam or cell is not providing said information or SI.

Said neighbor beam and/or cell information may be updated when the neighbors (e.g., neighboring beams or neighboring cells) start or stop transmitting.

A first group of method embodiments 300 in the UE is provided, through which the UE 100 acquires a first signal (as an example of the discovery signal), e.g., an SSB, SSB-like or a discovery signal from the RAN (e.g., from a first cell). The UE 100 may acquire and/or store the version tag associated to broadcast information (SIB1/OSI) from SSB, SSB-alike, or other discovery signals DRS.

The UE 100 may receive 302 an indication (e.g., from the version tag) that the SI (e.g., SIB1 and/or OSI) is transmitted 408, e.g. in a first beam or a first direction of the first cell (which may be collectively referred to as radio resources used for serving the UE 100) or in a second cell (which may be an example of an alternative radio resource).

In case the version tag differs from the stored version tag, and the broadcast information (e.g., the SI) is currently not transmitted in the current beam, the UE may ask 406 for on-demand provision 408 of the SI (e.g., SIB1 and/or OSI) in the current beam and/or direction and/or cell (which may be examples of the radio resources used for serving the UE 100).

A second group of method embodiments 300 in the UE 100 is provided, through which the UE 100 acquires one or more neighbor beam and/or directions and/or cell information (which may be examples of the alternative radio resources) from the RAN 500.

The UE 100 acquires the broadcast information (or parts thereof, which are referred to as SI herein) that is lacking in the current beam (as an example of the radio resources used for serving) from another beam or cell (as an example of the alternative radio resources).

Any of the above described or below listed embodiments may further comprise at least one of the features or steps described in the context of below detailed embodiments.

For concreteness and without limitation, the discovery signal is referred to as SSB, the RAN 500 is referred to network (NW), and the SI is referred to as SIB1 and/or OSI.

Furthermore, while below description refers to a system (e.g., comprising the NW 500 and at least UE 100) for conciseness, the skilled person appreciates that any one of the below described features and steps is disclosed for each of the UE 100 and the gNB 200 (as the base station) at the NW 500. The technique is related to a system in which broadcast 408 system information (SI) is omitted in one or more directions, channels, or beam within a cell or another cell to save NW energy. More specifically, a system in which one or more SSBs, or SSB-alike (or any DRS) are transmitted 402 in various beams but the broadcast NW information (e.g., the SI of the methods 300 and 400), fully or partially, such as SIB1 or other system information (OSI) is transmitted in none or a subset of beams with same or different periodicities within the same cell or another cell. For example, in a very low loaded NW scenario (where potential broadcast stands for a considerable portion of energy consumption), the broadcast information (e.g., the SI) is transmitted less frequent or not at all in beams or cells where there typically are no UEs present. Said broadcast information is instead transmitted (or transmitted at a higher rate) upon UE's on-demand request 306 via UL transmission (e.g., a WUS signal or alike).

However, the issue in such system is that there is a high risk for UEs 100 transmitting on-demands requests unnecessarily, when broadcast information is omitted by the NW 500 in their direction and/or beam or cell, as these UEs 100 already have the latest version of the broadcast information. These requests will also cause that the NW 500 might assume that there are many UEs 100 interested in receiving the information (e.g., SI) and therefore might turn on permanent (e.g., periodic) broadcast 408 while there is actually one or few UEs 100 transmitting the on-demand request. Therefore, the subject technique comprises methods 300 and 400 to alleviate said issues.

In one aspect, a version tag is provided 402 as part of the provided reference signal (SSB/SSB-alike/DRS, etc.), i.e. the discovery signal. Similar to the legacy value tag (which may be relevant to various SIBs) when the UEs 100 receive broadcast SIB1 or OSI, they also store the received associated version tag for that cell or beam and the broadcast messages. When the UE 100 is in that cell again, and if the NW 500 is currently not providing 408 the broadcast information (i.e., the SI, e.g. SIB1 and/or OSI), the UE 100 is assured that it does not need to ask for on-demand SIB1 and/or OSI provision in case the version tag matches the UE's stored one.

In one embodiment more than one version tag is used by the NW 500. For example, one for the SIB1 while another for OSI. The UE 100 may then ask for on-demand transmission for the information (SIB1 or OSI) where the version differs from the one that the UE 100 has stored. In another example, the version tag contains a bitmap or codepoint which indicates SIB1 and/or OSI in which beam or cell is the same or has changed.

In one embodiment, one or more validity timers are associated to one or more of the version tags. I.e., even if the UE's stored version tag matches the NW current transmitted, the UE 100 still has to ask for new transmission or has to recheck the version tag provided in SSB or SSB-like signal if the timer has elapsed since last time the UE acquired the broadcast information. The validity timer can be based on pre-configuration, e.g., as in standardization documentations or configurable by the NW 500.

In one embodiment, the one or more version tags are provided 402 as part of SSB (as an example of the discovery signal). For example, the version tag is provided 402 in the PBCH and/or Master Information Block (MIB) of the SSB. The indication may use the below bold-type bits in 3GPP-specified (TS 38.331) MIB:

MIB SEQUENCE { systemFrameNumber BIT STRING ( SI ZE ( 6 ) ) , subCarrierSpacingCommon ENUMERATED { s cs l5or60 , s cs 30orl20 } , s sb-SubcarrierOf f set INTEGER ( 0 . . 15 ) , dmrs-TypeA-Position ENUMERATED { pos2 , pos 3 } , pdcch-Conf igSIBl PDCCH-ConfigSIBl , cellBarred ENUMERATED { barred, notBarred } , intraFreqReselection ENUMERATED { allowed, notAllowed } , spare BIT STRING (SIZE ( 1 ) ) }

It shall be noted that the conventional MIB does not have more than one spare bit available. Hence, in one related embodiment, this spare bit is used as a version tag which is toggled upon SIB and/or OSI content updates by the NW. In another embodiment, some of the MIB contents are repurposed while SIB1 and/or OSI is not broadcast. For example, if SIB1 is not broadcast 408 by the NW 500, then the PDCCH-ConfigSIBl bits emphasized above may be used as version tag. In another embodiment, a combination of the spare bit and the repurposed bits are used to indicate 402 the version tag and that currently there is no SIB1 and/or OSI provided, e.g., the spare bit may be used to indicated that SIB1 and/or OSI is currently not broadcast and the PDCCH-ConfigSIBl contains the version tag(s).

In another embodiment, the characteristics of the sequence (e.g. time and/or frequency position, or sequence signature) is used as the version tag. For example, the NW 500 may change the sequence (or encoding thereof) upon broadcast contents update.

In another aspect of the invention, the NW 500 provides information about one or more potential neighboring beams or cells (as examples of the alternative radio resources) that is currently providing the broadcast information (e.g., the SI). For example, the UE 100 may be in a beam where SIB1 and/or OSI is not transmitted 408, but the UE 100 perceives good enough quality on a neighbor beam for acquiring SIB1 and/or OSI. The UE 100 may than instead of asking 406 for on- demand broadcast acquire SIB1/OSI from a neighbor beam or cell and thereby avoid both an energy consuming UL transmission (on-demand request) and a delay before the NW transmits the on-demand SIB1/OSI.

In one embodiment, the information about neighbor beam SIB1 and/or OSI or cell provision (e.g., as examples of the indication of the alternative radio resources) is within the SSB, e.g. via repurposed bits in MIB as exemplified earlier.

In another embodiment, the information about neighbor beam OSI provision is within the SIB1 or another SIB.

In one embodiment, the information is a bitmap where the bits represent one or more neighbor beams, e.g. either one-to-one mapping between the beams and the bits or one-to-many where one bit represents more than one neighbor beam. Said mapping can be part of configuration provided by the NW in dedicated/broadcast configuration or pre-specified.

In all aspects above, if other discovery reference signals (DRSs) are introduced, the version tag or the neighbor provision information may be provided there. E.g., a bitfield associated with DRS or SSB like signal can be used in order to convey the different version tags mentioned before, or alternatively, a specific sequence can entail that information. In this case, the bitfield or sequence can be preconfigured.

The version tags may, alternatively or in addition, be included in another SIB1 and/or OSI, e.g., if SIB1 and/or OSI of a first cell contains the version tags related to SIB1 and/or OSI of a second cell. Fig. 8 shows a schematic block diagram for an embodiment of the device 100. The device 100 comprises processing circuitry, e.g., one or more processors 804 for performing the method 300 and memory 806 coupled to the processors 804. For example, the memory 806 may be encoded with instructions that implement at least one of the modules 102, 104 and 106.

The one or more processors 804 may be a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, microcode and/or encoded logic operable to provide, either alone or in conjunction with other components of the device 100, such as the memory 806, radio device functionality. For example, the one or more processors 804 may execute instructions stored in the memory 806. Such functionality may include providing various features and steps discussed herein, including any of the benefits disclosed herein. The expression "the device being operative to perform an action" may denote the device 100 being configured to perform the action.

As schematically illustrated in Fig. 8, the device 100 may be embodied by a radio device 800, e.g., functioning as a UE. The radio device 800 comprises a radio interface 802 coupled to the device 100 for radio communication with one or more receiving stations, e.g., functioning as a receiving base station or a receiving UE.

Fig. 9 shows a schematic block diagram for an embodiment of the device 200. The device 200 comprises processing circuitry, e.g., one or more processors 904 for performing the method 400 and memory 906 coupled to the processors 904. For example, the memory 906 may be encoded with instructions that implement at least one of the modules 202, 204 and 206.

The one or more processors 904 may be a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, microcode and/or encoded logic operable to provide, either alone or in conjunction with other components of the device 200, such as the memory 906, base station functionality. For example, the one or more processors 904 may execute instructions stored in the memory 906. Such functionality may include providing various features and steps discussed herein, including any of the benefits disclosed herein. The expression "the device being operative to perform an action" may denote the device 200 being configured to perform the action.

As schematically illustrated in Fig. 9, the device 200 may be embodied by a base station 900, e.g., functioning as a gNB. The base station 900 comprises a radio interface 902 coupled to the device 200 for radio communication with one or more transmitting stations, e.g., functioning as a transmitting base station or a transmitting UE.

With reference to Fig. 10, in accordance with an embodiment, a communication system 1000 includes a telecommunication network 1010, such as a 3GPP-type cellular network, which comprises an access network 1011, such as a radio access network, and a core network 1014. The access network 1011 comprises a plurality of base stations 1012a, 1012b, 1012c, such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 1013a, 1013b, 1013c. Each base station 1012a, 1012b, 1012c is connectable to the core network 1014 over a wired or wireless connection 1015. A first user equipment (UE) 1091 located in coverage area 1013c is configured to wirelessly connect to, or be paged by, the corresponding base station 1012c. A second UE 1092 in coverage area 1013a is wirelessly connectable to the corresponding base station 1012a. While a plurality of UEs 1091, 1092 are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding base station 1012.

Any of the base stations 1012 and the UEs 1091, 1092 may embody the devices 200 and 100, respectively.

The telecommunication network 1010 is itself connected to a host computer 1030, which may be embodied in the hardware and/or software of a standalone server, a cloud-implemented server, a distributed server or as processing resources in a server farm. The host computer 1030 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. The connections 1021, 1022 between the telecommunication network 1010 and the host computer 1030 may extend directly from the core network 1014 to the host computer 1030 or may go via an optional intermediate network 1020. The intermediate network 1020 may be one of, or a combination of more than one of, a public, private or hosted network; the intermediate network 1020, if any, may be a backbone network or the Internet; in particular, the intermediate network 1020 may comprise two or more sub-networks (not shown).

The communication system 1000 of Fig. 10 as a whole enables connectivity between one of the connected UEs 1091, 1092 and the host computer 1030. The connectivity may be described as an over-the-top (OTT) connection 1050. The host computer 1030 and the connected UEs 1091, 1092 are configured to communicate data and/or signaling via the OTT connection 1050, using the access network 1011, the core network 1014, any intermediate network 1020 and possible further infrastructure (not shown) as intermediaries. The OTT connection 1050 may be transparent in the sense that the participating communication devices through which the OTT connection 1050 passes are unaware of routing of uplink and downlink communications. For example, a base station 1012 need not be informed about the past routing of an incoming downlink communication with data originating from a host computer 1030 to be forwarded (e.g., handed over) to a connected UE 1091. Similarly, the base station 1012 need not be aware of the future routing of an outgoing uplink communication originating from the UE 1091 towards the host computer 1030.

By virtue of the method 300 being performed by any one of the UEs 1091 or 1092 and/or the method 400 being performed by any one of the base stations 1012, the energy efficiency of the OTT connection 1050 can be improved, e.g., in terms of less power consumption at the RAN 500 or 1010. More specifically, the host computer 1030 may indicate to the RAN 300 or the relay radio device 200 or the remote radio device (e.g., on an application layer) a QoS of the traffic which triggers whether or not the SI is broadcast and/or whether or not the technique is applied.

Example implementations, in accordance with an embodiment of the UE, base station and host computer discussed in the preceding paragraphs, will now be described with reference to Fig. 11. In a communication system 1100, a host computer 1110 comprises hardware 1115 including a communication interface 1116 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 1100. The host computer 1110 further comprises processing circuitry 1118, which may have storage and/or processing capabilities. In particular, the processing circuitry 1118 may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The host computer 1110 further comprises software 1111, which is stored in or accessible by the host computer 1110 and executable by the processing circuitry 1118. The software 1111 includes a host application 1112. The host application 1112 may be operable to provide a service to a remote user, such as a UE 1130 connecting via an OTT connection 1150 terminating at the UE 1130 and the host computer 1110. In providing the service to the remote user, the host application 1112 may provide user data, which is transmitted using the OTT connection 1150. The user data may depend on the location of the UE 1130. The user data may comprise auxiliary information or precision advertisements (also: ads) delivered to the UE 1130. The location may be reported by the UE 1130 to the host computer, e.g., using the OTT connection 1150, and/or by the base station 1120, e.g., using a connection 1160.

The communication system 1100 further includes a base station 1120 provided in a telecommunication system and comprising hardware 1125 enabling it to communicate with the host computer 1110 and with the UE 1130. The hardware 1125 may include a communication interface 1126 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 1100, as well as a radio interface 1127 for setting up and maintaining at least a wireless connection 1170 with a UE 1130 located in a coverage area (not shown in Fig. 11) served by the base station 1120. The communication interface 1126 may be configured to facilitate a connection 1160 to the host computer 1110. The connection 1160 may be direct, or it may pass through a core network (not shown in Fig. 11) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system. In the embodiment shown, the hardware 1125 of the base station 1120 further includes processing circuitry 1128, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The base station 1120 further has software 1121 stored internally or accessible via an external connection.

The communication system 1100 further includes the UE 1130 already referred to.

Its hardware 1135 may include a radio interface 1137 configured to set up and maintain a wireless connection 1170 with a base station serving a coverage area in which the UE 1130 is currently located. The hardware 1135 of the UE 1130 further includes processing circuitry 1138, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The UE 1130 further comprises software 1131, which is stored in or accessible by the UE 1130 and executable by the processing circuitry 1138. The software 1131 includes a client application 1132. The client application 1132 may be operable to provide a service to a human or non-human user via the UE 1130, with the support of the host computer 1110. In the host computer 1110, an executing host application 1112 may communicate with the executing client application 1132 via the OTT connection 1150 terminating at the UE 1130 and the host computer 1110. In providing the service to the user, the client application 1132 may receive request data from the host application 1112 and provide user data in response to the request data. The OTT connection 1150 may transfer both the request data and the user data. The client application 1132 may interact with the user to generate the user data that it provides.

It is noted that the host computer 1110, base station 1120 and UE 1130 illustrated in Fig. 11 may be identical to the host computer 1030, one of the base stations 1012a, 1012b, 1012c and one of the UEs 1091, 1092 of Fig. 10, respectively. This is to say, the inner workings of these entities may be as shown in Fig. 11, and, independently, the surrounding network topology may be that of Fig. 10.

In Fig. 11, the OTT connection 1150 has been drawn abstractly to illustrate the communication between the host computer 1110 and the UE 1130 via the base station 1120, without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from the UE 1130 or from the service provider operating the host computer 1110, or both. While the OTT connection 1150 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network).

The wireless connection 1170 between the UE 1130 and the base station 1120 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the UE 1130 using the OTT connection 1150, in which the wireless connection 1170 forms the last segment. More precisely, the teachings of these embodiments may reduce the latency and improve the data rate and thereby provide benefits such as better responsiveness and improved QoS.

A measurement procedure may be provided for the purpose of monitoring data rate, latency, QoS and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 1150 between the host computer 1110 and UE 1130, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection 1150 may be implemented in the software 1111 of the host computer 1110 or in the software 1131 of the UE 1130, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection 1150 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software 1111, 1131 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 1150 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect the base station 1120, and it may be unknown or imperceptible to the base station 1120. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling facilitating the host computer's 1110 measurements of throughput, propagation times, latency and the like. The measurements may be implemented in that the software 1111, 1131 causes messages to be transmitted, in particular empty or "dummy" messages, using the OTT connection 1150 while it monitors propagation times, errors etc.

Fig. 12 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figs. 10 and 11. For simplicity of the present disclosure, only drawing references to Fig. 12 will be included in this paragraph. In a first step 1210 of the method, the host computer provides user data. In an optional substep 1211 of the first step 1210, the host computer provides the user data by executing a host application. In a second step 1220, the host computer initiates a transmission carrying the user data to the UE. In an optional third step 1230, the base station transmits to the UE the user data which was carried in the transmission that the host computer initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional fourth step 1240, the UE executes a client application associated with the host application executed by the host computer.

Fig. 13 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figs. 10 and 11. For simplicity of the present disclosure, only drawing references to Fig. 13 will be included in this paragraph. In a first step 1310 of the method, the host computer provides user data. In an optional substep (not shown) the host computer provides the user data by executing a host application. In a second step 1320, the host computer initiates a transmission carrying the user data to the UE. The transmission may pass via the base station, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional third step 1330, the UE receives the user data carried in the transmission.

As has become apparent from above description, at least some embodiments of the technique avoid unnecessary transmission of requests for SIB1 and/or OSI from the UEs and/or on-demand transmissions of SIB1 and/or OSI from the RAN. Same or further embodiments allow the RAN (e.g., a gNB) to be more aggressive in turning off transmissions of SIB1 and/or OSI, e.g. in certain beams or cells, as the RAN can rely on that UEs will ask for the transmission when necessary, e.g. by virtue of the provided indications.

Same of further embodiment can achieve energy improvements for the RAN and the society. These energy improvements can be captured in operation of the RAN and/or the radio device served by the RAN, particularly at the node equipment and at the network level.

Many advantages of the present invention will be fully understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the units and devices without departing from the scope of the invention and/or without sacrificing all of its advantages. Since the invention can be varied in many ways, it will be recognized that the invention should be limited only by the scope of the following list of claims.