A method of controlling a base station in a telecommunications network, a method of a User Equipment communicating with a base station in a telecommunications network, a base station, a user equipment and a computer program

Abstract

Reducing power consumption and improving efficiency of 5G base station sites, by controlling a base station in a telecommunications network to broadcast synchronisation signals, and particularly to se

Description

Field of the invention

[0001] The present invention relates to controlling broadcast of synchronisation signals in a telecommunications network. In particular, the invention relates to selectively enabling and disabling periodic broadcast of a system information block one. Glossary MNO - Mobile Network Operator RF - Radiofrequency SA - Standalone RRC - Radio Resource Control SSB - Synchronisation Signal Block PSS - Primary Synchronization Signal SSS - Secondary Synchronization Signal PBCH - Physical Broadcast Channel DMRS - DeModulation Reference Signal BCCH - Broadcast Channel PDSCH - Physical Data Shared Channel PDCCH - Physical Downlink Control Channel SI - System Information MIB - Master Information Block SIB-System Information Block RMSI - Remaining Minimum System Information IE - Information Element CORESET - Control Resource Set LSB - Least Significant Bit MSB - Most Significant Bit RACH - Random Access Channel PRACH - Physical Random Access Channel FR1 - Frequency Range 1 FR2 - Frequency Range 2 GSCN - Global Synchronization Channel Number PCI - Physical layer Cell ID OTT - Over The Top RAN - Radio Access Network UE - User Equipment BS - Base Station ABS - Advanced Base Station BTS - Base Transceiver Station BSS - Basic Service Set ESS - Extended Service Set AP - Access Point NB - Node B (Radio Base Station Receiver) eNB - Evolved Node B gNB - Next-Generation Node B TRP - Transmission and Reception Point PS - Processing Server TE - Terminal Equipment MS - Mobile Station MT - Mobile Terminal UT - User Terminal SS - Subscriber Station PDA - Personal Digital Assistant CDMA - Code Division Multiple Access FDMA - Frequency Division Multiple Access TDMA - Time Division Multiple Access OFDMA - Orthogonal Frequency Division Multiple Access SC-FDMA - Single Carrier Frequency Division Multiple Access MC-FDMA - Multicarrier Frequency Division Multiple Access UTRA- Universal Terrestrial Radio Access GSM - Global System for Mobile Communications (2G) GSMA - GSM Association GPRS - General Packet Radio Service EDGE - Enhanced Data Rates for GSM Evolution IEEE - Institute of Electrical and Electronics Engineers E-UTRA-Evolved UTRA UMTS - Universal Mobile Telecommunications System (3G) E-UMTS - Evolved UMTS 3GPP - 3rd Generation Partnership Project DL - Downlink UL-Uplink LTE - Long Term Evolution (4G) LTE-A - LTE-Advanced NR - New Radio (5G) FDD - Frequency Division Duplex TDD - Time Division Duplex CRS - Cell-specific Reference Signal CSI-RS - Channel State Information Reference Signal FPGA - Field-Programmable-Gate-Array ASIC - Application-Specific-lntegrated-Circuit DSP - Digital-Signal-Processor CD-ROM - Compact Disc Read-Only Memory DVD-ROM - Digital Versatile Disc Read-Only Memory ROM - Read-Only Memory RAM - Random-Access Memory EEPROM - Electrically Erasable Programmable Read-Only Memory EPROM - Erasable Programmable Read-Only Memory Background

[0002] According to recent GSMA reports, the energy cost for mobile networks accounts for between 20% and 40% of the total operator cost. According to techno-econometric studies during the last decade, the base stations in the radio access network and the data centers are the elements in mobile networks that consume the most power. Overall, the majority of network energy usage is attributable to network base station sites. It is therefore desirable for Mobile Network Operators (MNOs) to propose energy saving techniques to reduce the power consumption of the base station sites.

[0003] In 5G, energy consumption of 5G sites (measured in kWh) is contingent on the energy consumption of installed equipment, rather than on the transferred data units. The 22 01 26 increase in total energy consumption in 5G sites is likely due to the need for more antennas, more frequency bands, and a denser layer of small cells, rather than increased data capacity. Within the base station, the largest component of energy consumption is the radiofrequency (RF) equipment (power amplifier plus transceivers and cables), which 5 typically uses about 65% of total energy. Improving energy efficiency to consume less energy can be achieved through a variety of solutions, including smart building, virtualizing the core, and enhancing RAN efficiency through modernization of legacy equipment and implementation of low-powered solutions. 10

[0004] In one example, a telecommunications equipment supplier estimates that a typical 5G site needs around 11.5 kW of power (around 70 percent more than a 2G / 3G / 4G base station providing a similar level of coverage). This equates to around 100 thousand kWh (3.6GJ) per year for one 5G site (which might cost around 30 thousand Euros per site per year). A mobile network operator might have around 15 thousand sites in a country the size 15 of Germany, which would consume 1.5 billion kWh (5.4PJ) of energy per year (costing around 450 million Euros per year).

[0005] Due to the high energy demand of 5G systems, it is a goal of the present disclosure to reduce power consumption and improve efficiency of 5G base station sites (as well as 20 UE power consumption and efficiency). Summary

[0006] A method of controlling a base station in a telecommunications network to disable 25 or continue periodic broadcast of a system information block one, SIB1, is provided. The method comprises broadcasting an indication that periodic broadcast of the SIB1 is scheduled to be disabled.

[0007] In option a), the method further comprises: 30 receiving, from a User Equipment, UE, an indication that the UE requires periodic broadcast of the SIB1; and controlling the base station to continue periodic broadcast of the SIB1.

[0008] In option b), the method further comprises: 22 01 26 determining that no indication that a UE requires periodic broadcast of the SIB1 has been received during a predetermined period of time; and controlling the base station to disable periodic broadcast of the SIB1. 5

[0009] The above method relates to a scenario where the base station is initially periodically broadcasting SIB1, but has determined that periodic broadcast of SIB1 could be disabled. The base station therefore indicates its intention to disable periodic broadcast of SIB1 to any UEs camped on the cell. If one or more UEs camped on the cell object to SIB1 being disabled, they may send an indication to the base station that the UE requires 10 periodic broadcast of SIB1. If the base station receives an indication from a UE that the UE requires broadcast of the SIB1, the base station continues periodic broadcast of SIB1, rather than disabling periodic broadcast of SIB1. Otherwise, if no such indication is received within a predetermined time period, the base station disables periodic broadcast of SIB1. 15

[0010] The indication is a signal from the base station to the UE that the base station intends to disable SIB1. The indication that periodic broadcast of the SIB1 is scheduled to be disabled could therefore be referred to as an indication that the base station intends to disable periodic broadcast of the SIB1. The UE receives the signal and discerns the 20 meaning of the indication from the base station. If the meaning of the indication is correctly understood by the UE, the UE determines that that the base station has sent a signal indicating that it intends to disable SIB1. Nevertheless, the UE may not have access to the settings of the base station and may not be able to unequivocally determine that the base station intends to disable periodic broadcast of the SIB1. 25

[0011] The indication from the UE may be received in response to the indication that periodic broadcast of SIB1 is scheduled to be disabled. In other words, the UE may receive the indication that the base station intends to disable broadcast of SIB1 and respond with an indication that the UE still requires periodic broadcast of the SIB1. 30

[0012] The predetermined period of time may be a period beginning at the time of broadcast of the indication that periodic broadcast of the SIB1 is scheduled to be disabled.

[0013] The UE may be camped on a cell associated with the base station. The UE may be 35 a UE that has completed an attach procedure with the base station (e.g., a Standalone 22 01 26 (SA) initial attach process). The UE may have established an RRC connection with the base station. The RRC connection of the UE may be suspended or released. In other words, the UE may be in RRC inactive or RRC idle mode. 5

[0014] The base station may broadcast the indication to all UEs in a coverage area of the base station. The broadcast may be received and decoded by all UEs in the coverage area that are camped on the cell associated with the base station.

[0015] The method may further comprise identifying an opportunity to disable periodic 10 broadcast of the SIB1 by determining that there are no UEs connected to the base station (in RRC Connected state). This determination may be made prior to broadcasting the indication that periodic broadcast of the SIB1 is scheduled to be disabled.

[0016] The indication that periodic broadcast of the SIB1 is scheduled to be disabled may 15 be provided by a parameter in a master information block, MIB.

[0017] Alternatively, the indication that periodic broadcast of the SIB1 is scheduled to be disabled may be provided by a parameter (e.g., an information element) in the SIB1. 20

[0018] Additionally or alternatively, the indication that periodic broadcast of the SIB1 is scheduled to be disabled may be provided by data in the PBCH or PDSCH.

[0019] The parameter may be a flag (a single bit) that is set or cleared to indicate that periodic broadcast of the SIB1 is scheduled to be disabled. 25

[0020] The MIB is defined in clause 6.2.2 of 3GPP TS 38.331. The MIB comprises 23 bits of data, including a “spare bit” (plus one additional bit to indicate the BCCH message type). Where the indication is provided by a parameter in the MIB, the indication may be provided using the “spare bit” in the MIB. 30

[0021] The spare bit is a flag that may be set or cleared to indicate that periodic broadcast of the SIB1 is scheduled to be disabled. 22 01 26

[0022] The MIB may be broadcast by the base station. The method may further comprise broadcasting the MIB. The MIB may be periodically broadcast by the base station. The method may further comprise periodically broadcasting the MIB. 5

[0023] The indication that periodic broadcast of the SIB1 is scheduled to be disabled may be provided by one or more of: a subcarrier offset, kssb; a subcarrier spacing; a search space, SearchspaceO; 10 a control resource set, CORESET0; a pdcch-ConfigSIB1 information element in the MIB; a spare bit in the MIB; and one or more other parameters in the MIB (such as a ssb-SubcarrierOffset information element). 15

[0024] The method may further comprise periodically broadcasting the SIB1 (prior to controlling the base station to disable periodic broadcast of the SIB1).

[0025] The indication that periodic broadcast of the SIB1 is scheduled to be disabled may 20 be provided by a parameter in the SIB1.

[0026] A method of configuring a user equipment, UE, in a telecommunications network is provided. The method comprises sending, from an alternative base station to the UE, configuration corresponding to a target base station. The configuration is for sending an 25 indication to the target base station that the UE requires periodic broadcast of a system information block one, SIB1, from the target base station.

[0027] Sending the configuration (from the base station to the UE) may comprise sending a system information block one, SIB1, corresponding to the base station. The SIB1 30 corresponding to the base station may comprise the configuration corresponding to the target base station.

[0028] The configuration may be sent to the UE at a first point in time and the UE may be configured to send the indication that periodic broadcast of SIB1 is required to the target 22 01 26 base station at a second point in time later than the first point in time. The UE may not be in communication with the base station at the second point in time.

[0029] The base station (which may be referred to elsewhere as an alternative base 5 station) may be a different cell entity to the target base station.

[0030] A method of controlling a base station in a telecommunications network to activate periodic broadcast of a system information block one, SIB1, is provided. The method comprises receiving, from a User Equipment, UE, an indication that the UE requires 10 periodic broadcast of the SIB1. The method further comprises controlling the base station to activate periodic broadcast of the SIB1.

[0031] The above method relates to a scenario where the base station is not initially periodically broadcasting SIB1. The base station determines (through receipt of an 15 indication from a UE) that a UE requires periodic broadcast of SIB1. When the base station receives the indication from the UE that the UE requires periodic broadcast of the SIB1, the base station activates periodic broadcast of SIB1.

[0032] The base station may be a target base station. The method may be a method of a 20 telecommunications network controlling the target base station. The method may further comprise configuring the UE via an alternative base station (by a method as described above). The indication that the UE requires periodic broadcast of the SIB1 may be received by the target base station. The indication that the UE requires periodic broadcast of the SIB1 may be an indication that the UE requires periodic broadcast of the SIB1 from the 25 target base station.

[0033] Where the base station “activates periodic broadcast of the SIB1 ”, this may be performed in a scenario where the base station was previously broadcasting the SIB1 and that broadcast was disabled. In other words, the base station may re-activate periodic 30 broadcast of the SIB1. This may also be performed in a scenario where the base station has not previously disabled periodic broadcast of SIB1 and is activating periodic broadcast of the SIB1 for the first time. Therefore, in the context of this of this application, “activate”, “activates” or “activating” may be understood to encompass both meanings. 22 01 26

[0034] The indication may be received directly from the UE and not from another base station over the X2 / Xn interface. This method may therefore be used in situations where the UE is not in communication with another base station. 5

[0035] The method may further comprise broadcasting (e.g., by the target base station) a master information block, MIB. The method may further comprise periodically broadcasting the MIB.

[0036] The MIB may comprise an indication that periodic broadcast of the SIB1 is disabled 10 (prior to activation of the SIB1, at which point the MIB may be updated).

[0037] The indication that periodic broadcast of the SIB1 is disabled may be provided by a parameter in the MIB. 15

[0038] The indication that periodic broadcast of the SIB1 is disabled may be provided by one or more of: a spare bit in the MIB; a subcarrier offset, kssb; a subcarrier spacing; 20 a search space, SearchspaceO; a control resource set, CORESET0.

[0039] The spare bit in the MIB is a flag that may be set or cleared to indicate that periodic broadcast of the SIB1 is currently disabled. 25

[0040] The subcarrier offset, kSSb, may be defined (at least partially) by one or more of: a ssb-SubcarrierOffset information element in the MIB; one or more additional bits of data provided in a physical broadcast channel, PBCH, payload. 30

[0041] The four least significant bits (LSBs) of kSSb may be provided by the ssb-subcarrierOffset information element. The one most significant bit (MSB) may be provided by additional bit aA+5 in the PBCH payload. This is described in clause 7.1.1 of 3GPP TS 38.212, which is herein incorporated by reference. 22 01 26

[0042] The PBCH payload may comprise the MIB, in other words the MIB is broadcast via the physical broadcast channel.

[0043] The search space, SearchspaceO, and / or the control resource set, CORESET0, 5 may be defined (at least partially) by a pdcch-ConfigSIB1 information element in the MIB. As specified in clause 6.3.2 of 3GPP TS 38.331, the four least significant bits (LSBs) of pdcch-ConfigSIB1 may be used to determine CORESET0 and the four most significant bits (MSBs) of pdcch-ConfigSIB1 may be used to determine SearchspaceO. 10

[0044] The base station may indicate to the UE that no SIB1 is currently being broadcast via the “noSIBI” indication, as specified in clause 6.3.2 of 3GPP TS 38.331.

[0045] The indication that periodic broadcast of the SIB1 is disabled may be closely related to the indication periodic broadcast of the SIB1 is scheduled to be disabled. The same one 15 or more parameters may be used by the base station to broadcast each indication. In some examples, the values of the one or more parameters may even be the same for the two indications. For example, the spare bit on the MIB may be set to indicate that periodic broadcast of SIB1 is scheduled to be disabled. Once periodic broadcast of SIB1 has been disabled, the spare bit on the MIB may remain set to indicate that periodic broadcast of the 20 MIB is currently disabled. The bit may be cleared once periodic broadcast of the MIB is reactivated.

[0046] Alternatively, the indication that periodic broadcast of the SIB1 is disabled may be broadcast via a different set of one or more parameters to the indication that periodic 25 broadcast of the SIB1 is scheduled to be disabled. For example, the indication that periodic broadcast of the SIB1 is disabled may be broadcast via the MIB, whilst the indication that periodic broadcast of the SIB1 is scheduled to be disabled may be broadcast via the SIB1.

[0047] The method may further comprise periodically broadcasting the SIB1. The method 30 may further comprise broadcasting an updated MIB. The method may further comprise broadcasting an updated MIB. The updated MIB may comprise an indication that periodic broadcast of the SIB1 is enabled. The SIB1 and / or updated MIB may be broadcast after controlling the base station to activate periodic broadcast of the SIB1. 22 01 26

[0048] In other words, once periodic broadcast of SIB1 is reactivated, the parameters previously used to indicate that periodic broadcast of the SIB1 is disabled may be updated to reflect the fact that periodic broadcast of the SIB1 has been enabled. 5

[0049] In a similar manner to the indication that periodic broadcast of the SIB1 is disabled, the indication that periodic broadcast of the SIB1 is enabled may comprise one or more of: a subcarrier offset, kssb; a subcarrier spacing; a search space, SearchspaceO; 10 a control resource set, CORESET0.

[0050] The methods of controlling the base station to disable and enable periodic broadcast of the SIB1 are complementary and may be used together to selectively disable and re-activate periodic broadcast of the SIB1. In one example, a method of controlling a 15 base station in a telecommunications network comprises: broadcasting an indication that periodic broadcast of the SIB1 is scheduled to be disabled; determining that no indication that a UE requires periodic broadcast of the SIB1 has been received during a predetermined period of time; and 20 controlling the base station to disable periodic broadcast of the SIB1; receiving, from a UE (and at a later point in time), an indication that the UE requires periodic broadcast of the SIB1; and controlling the base station to activate periodic broadcast of the SIB1. 25

[0051] By selectively deactivating and reactivating periodic broadcast of the SIB1, the base station is able to reduce power consumption while maintaining coverage.

[0052] A method of a User Equipment, UE, communicating with a base station in a telecommunications network to prevent the base station from disabling periodic broadcast 30 of a system information block one, SIB1, is also provided. The method comprises receiving an indication that periodic broadcast of the SIB1 is scheduled to be disabled. The method further comprises sending to the base station an indication that the UE requires periodic broadcast of the SIB1 (or at least currently requires periodic broadcast of the SIB1). 22 01 26

[0053] The above method relates to a scenario where the base station is initially periodically broadcasting SIB1, but has indicated that periodic broadcast of SIB1 will be disabled, unless one or more UEs camped on the cell take appropriate action to object. The UE determines, through receipt of the indication from the base station, that the base 5 station is planning to disable periodic broadcast of SIB1. In response, the UE sends an indication to the base station that the UE requires periodic broadcast of SIB1. When the base station receives the indication from the UE that the UE requires periodic broadcast of the SIB1, the base station continues periodic broadcast of SIB1, rather than disabling periodic broadcast of SIB1, in accordance with the method described earlier. 10

[0054] In this way, the UE is able to “prevent” the base station from disabling periodic broadcast of SIB1 (in other words, the UE induces the base station to continue periodic broadcast of SIB1). The UE does not force the base station to continue periodic broadcast of SIB1, rather the UE indicates that it requires periodic broadcast of SIB1 and relies on the 15 behaviour of the base station to continue periodic broadcast of the SIB1. In this way, by indicating that periodic broadcast of SIB1 is required, the base station is prevented from disabling periodic broadcast of SIB1.

[0055] The indication that the UE requires periodic broadcast of the SIB1 may comprise a 20 random access preamble (e.g., a RACH preamble). Additionally or alternatively, the indication that the UE requires periodic broadcast of the SIB1 may sent via a physical random access channel (PRACH). In this way, the UE may be able to send the indication to the base station, without transitioning to a connected state. 25

[0056] The method may further comprise receiving and decoding the SIB1. The SIB1 may comprise configuration for sending the indication (that the UE requires periodic broadcast of the SIB1) to the base station. The indication that the UE requires periodic broadcast of the SIB1 may be sent using the configuration decoded from the SIB1. 30

[0057] Receiving and decoding the SIB1 may comprise receiving a broadcast comprising a SIB1 (e.g., a message broadcast via a Physical Data Shared Channel, PDSCH) and decoding the SIB1 from the broadcast.

[0058] The configuration may be random access channel, RACH, configuration. 22 01 26

[0059] The UE may obtain the RACH configuration for sending the request from a SIB1 received and decoded by the UE in the past. Receiving and decoding the SIB1 may refer to the SIB1 that is currently being periodically broadcast by the base station (the transmission that is about to be stopped). Alternatively, the RACH configuration for sending the request 5 may have been obtained by the UE from reception of a SIB1 that was broadcast previously by the base station (or by an alternative base station).

[0060] In some examples, the indication (that the UE requires periodic broadcast of the SIB1) may be implicit. In other words, the UE may indicate to the base station that periodic 10 broadcast of SIB1 is required by sending a message using the configuration provided in the SIB1. For example, the UE may request another SIB (e.g., via the SI-RequestConfig information element).

[0061] The indication that the UE requires periodic broadcast of the SIB1 may comprise a 15 request for a system information block.

[0062] The request for a system information block may comprise a SI-RequestConfig information element. 20

[0063] The method may further comprise receiving and decoding a master information block, MIB, from the base station. The MIB may comprise the indication that periodic broadcast of the SIB1 is scheduled to be disabled.

[0064] The indication that periodic broadcast of the SIB1 is scheduled to be disabled may 25 be provided by one or more of: a subcarrier offset, kssb; a subcarrier spacing; a search space, SearchspaceO; a control resource set, CORESET0; 30 a pdcch-ConfigSIB1 information element in the MIB; a spare bit in the MIB; and one or more other parameters in the MIB.

[0065] The subcarrier offset, kSSb, may be defined by one or more of: 35 a ssb-SubcarrierOffset information element in the MIB; 22 01 26 one or more additional bits of data provided in a physical broadcast channel, PBCH, payload.

[0066] A method of a User Equipment, UE, communicating with a target base station in a 5 telecommunications network to cause the target base station to activate periodic broadcast of a system information block one, SIB1, is also provided. The method comprises determining that periodic broadcast of the SIB1 by the target base station is disabled. The method further comprises sending, to the target base station, an indication that the UE requires periodic broadcast of SIB1. 10

[0067] The above method relates to a scenario where the base station is not initially periodically broadcasting SIB1. The UE determines (e.g., through receipt of an indication broadcast by the base station via another information block, such as the MIB) that periodic broadcast of the SIB1 is disabled. In other words, the UE determines that SIB1 is not being 15 periodically broadcast by the base station. In response, the UE sends an indication to the base station that the UE requires periodic broadcast of SIB1. When the base station receives the indication from the UE that the UE requires periodic broadcast of the SIB1, the base station activates periodic broadcast of SIB1, in accordance with the method described earlier. 20

[0068] The indication that the UE requires periodic broadcast of the SIB1 may comprise a request for a system information block (e.g., a SIB other than the SIB1).

[0069] The request for a system information block may comprise a SI-RequestConfig 25 information element.

[0070] The method further comprises determining configuration for sending the indication to the target base station. 30

[0071] The configuration may be random access channel, RACH, configuration.

[0072] Determining configuration comprises receiving configuration from an alternative base station. The configuration corresponds to the target base station. 22 01 26

[0073] In some alternative examples, determining configuration may comprise using predetermined configuration. The predetermined configuration may be defined in the standards and pre-configured in the UE. 5

[0074] In other alternative examples, determining configuration may comprise receiving configuration from the base station during an attach procedure.

[0075] The UE may obtain the RACH configuration for sending the request from a SIB1 received and decoded by the UE in the past. Receiving and decoding the SIB1 may refer to 10 a SIB1 that was broadcast previously by the base station prior SIB1 broadcast being disabled. In other words, the UE may store the RACH configuration from a previous time the UE was camped on the cell (when SIB1 broadcast was active) and use that same RACH configuration when SIB1 broadcast is disable to request that the base station reactivate SIB1 broadcast. 15

[0076] Receiving configuration corresponding to the target base station may comprise receiving, from the alternative base station, a SIB1 corresponding to the alternative base station. The SIB1 corresponding to the alternative base station may comprise the 20 configuration corresponding to the target base station.

[0077] The configuration may be received from the alternative base station at a first point in time. The UE may send the indication that periodic broadcast of SIB1 is required at a second point in time later than the first point in time. The UE may not be in communication 25 with the alternative base station at the second point in time.

[0078] In other words, the UE may obtain the RACH configuration for sending the request from a SIB1 received and decoded by the UE in the past. Receiving and decoding the SIB1 may refer to a SIB1 that was broadcast previously by an alternative base station. 30

[0079] The SIB1 corresponding to the alternative base station may be received at an earlier point in time when the UE was camped on the alternative base station. At the time the UE is trying to camp on the target base station, the alternative base station may no longer be available. 22 01 26

[0080] The alternative base station may be a different cell entity but could be co-located with the target base station.

[0081] The method may further comprise storing the configuration until it is needed. 5

[0082] Determining that periodic broadcast of the SIB1 is disabled may comprise receiving and decoding a master information block, MIB, from the base station, wherein the MIB comprises an indication that periodic broadcast of the SIB1 is disabled. 10

[0083] Receiving and recoding the MIB may comprise receiving a Signal Synchronisation Block (SSB) comprising a PBCH payload and decoding the PBCH payload.

[0084] The indication that periodic broadcast of the SIB1 is disabled may be provided by a flag in the MIB. The flag may be a single bit that is set or cleared to indicate that periodic 15 broadcast of the SIB1 is disabled. The indication that periodic broadcast of the SIB1 is disabled may be provided using the spare bit in the MIB.

[0085] The indication that periodic broadcast of the SIB1 is disabled may be provided by a subcarrier offset. 20

[0086] The subcarrier offset may be defined (at least partially) by one or more of: a ssb-SubcarrierOffset information element in the MIB; one or more additional bits of data provided in a physical broadcast channel, PBCH, payload. 25

[0087] The ssb-SubcarrierOffset information element in the MIB is defined at clause 6.2.1 of 3GPP TS 38.331. The ssb-SubcarrierOffset corresponds to kSSb, which is the frequency domain offset between the SSB and the overall resource block grid, where the offset is provided in terms of a number of subcarriers. The value range of this field may be extended 30 by an additional most significant bit encoded within PBCH (as described in 3GPP TS 38.213). This field may indicate that this cell does not provide SIB1 and that there is hence no CORESET0 configured in MIB. In this case, the field pdcch-ConfigSIB1 may indicate the frequency positions where the UE may (not) find a SS / PBCH with a control resource set and search space for SIB1. 22 01 26

[0088] The time-frequency structure of an SSB (also called “Synchronisation Signal Block” or “SS / PBCH block”) is described in clause 7.4.3.1 of 3GPP TS 38.211, which is herein incorporated by reference. 5

[0089] The indication that periodic broadcast of the SIB1 is disabled may be provided by a pdcch-ConfigSIB1 information element in the MIB.

[0090] The indication that periodic broadcast of the SIB1 is disabled may be provided by one or more of: 10 a subcarrier spacing; a search space, SearchspaceO; a control resource set, CORESET0; and one or more other parameters in the MIB. 15

[0091] In some examples, the subcarrier offset, kSSb, may be used to determine whether a CORESET0 or SearchspaceO are present. This is defined in clauses 4.1 and 13 of 3GPP TS 38.213. Upon detection of a SS / PBCH block, the UE may determine that a CORESET0 (also referred to as a control resource set for TypeO-PDCCH common search space), is present if kSSB <23 for FR1 or if kSSB <11 for FR2. The UE may determine that CORESET0 20 is not present if kSSB >23 for FR1 or if kSSB >11 for FR2. If CORESET0 is not present, the UE may determine that periodic broadcast of the SIB1 is disabled.

[0092] If a UE detects a SSB and determines that a CORESET0 is not present, and for kSSB = 31 for FR1 or for kSSB = 15 for FR2, the UE may determine that there is no SSB 25 having an associated SearchspaceO (also called TypeO-PDCCH common search space) within a GSCN range [C"“ - + «»]• &and are respectively determined by the four most significant bits and the four least significant bits of pdcch-ConfigSIB1. If the GSCN range is ’Ngs^ UE may determine that there is no information for a second SSB with a CORESET0 on the detected SSB. The 30 UE may therefore determine that SIB1 is not being broadcast. 22 01 26

[0093] Reception of SIB1 is described in clause 5.2.5.5 of 3GPP TS 38.300, which is herein incorporated by reference. The Master Information Block (MIB) on PBCH may provide the UE with parameters (e.g. CORESET0 configuration) for monitoring of PDCCH for scheduling PDSCH that carries the System Information Block 1 (SIB1). PBCH may also 5 indicate that there is no associated SIB1. In the proposed methods, SIB1 is not being broadcast. Therefore, the UE may determine (e.g., from the 4 MSBs of the pdcch-ConfigSIBI IE) a frequency range where the UE may assume no SSB associated with SIB1 is present. 10

[0094] The method may further comprise determining a search space (e.g., a TypeO- PDCCH common search space). The method may further comprise monitoring the search space. The method may further comprise receiving and decoding the SIB1.

[0095] Receiving and decoding the SIB1 may comprise receiving a broadcast comprising a 15 SIB1 (e.g., a message broadcast via a Physical Data Shared Channel, PDSCH) and decoding the SIB1 from the broadcast.

[0096] The search space may be determined from a Master Information Block, MIB. The search space may be determined from the MIB broadcast prior to enabling periodic 20 broadcast of SIB1. Alternatively, the search space may be determined from an updated MIB broadcast once periodic broadcast of SIB1 is enabled.

[0097] The search space may be referred to as a “common search space”, since the search space is common to all UEs camped on the cell. searchspaceO is a specific 25 common search space used for the PDCCH carrying the SIB1.

[0098] searchspaceO is not the only common search space. Other common search spaces may be used for reception of other SIBs, Group config, random access, paging, and the like. 30

[0099] The method may further comprise determining a control resource set, CORESET0, from the MIB. 22 01 26

[0100] As with the search space, the control resource set may be determined from the MIB broadcast prior to enabling periodic broadcast of SIB1 or from an updated MIB broadcast once periodic broadcast of SIB1 is enabled. 5

[0101] The search space and / or the control resource set may be determined from a pdcch- ConfigSIBI information element in the MIB.

[0102] The method may further comprise determining a subcarrier offset from the MIB. Receiving the SIB1 may comprise using the subcarrier offset to receive and decode the 10 SIB1.

[0103] The subcarrier offset may be determined from the original MIB, if a spare bit is used to indicate that SIB1 is not being broadcast. Alternatively, if the subcarrier offset associated with the original MIB is used to indicate that SIB1 is not being broadcast, the subcarrier 15 offset may be determined from an updated MIB that is broadcast once periodic broadcast of SIB1 is enabled.

[0104] The method may further comprise receiving and decoding an updated MIB (once periodic broadcast of SIB1 is enabled). Receiving the SIB1 may comprise using updated 20 parameters in the updated MIB to receive and decode the SIB1.

[0105] Receiving and decoding an updated MIB may comprise receiving a broadcast (e.g., a message broadcast via a Physical Broadcast Channel, PBCH) comprising an updated MIB and decoding the updated MIB from the broadcast. 25

[0106] In one example, the updated MIB may comprise an updated subcarrier offset, updated control resource set, and / or an updated common search space.

[0107] A base station configured to perform the methods described above is also provided. 30 The base station may be the target base station or the alternative base station.

[0108] A telecommunications network configured to perform the methods described above is also provided. 22 01 26

[0109] A User Equipment, UE, configured to perform the methods described above is also provided.

[0110] A computer program comprising instructions that, when executed on a processor, 5 cause the processor to perform the methods described above is also provided. Brief description of the drawings

[0111] Fig. 1 illustrates a method for receiving SIB1 for cell 1 from cell 2. 10

[0112] Fig. 2 illustrates a method for requesting cell 2 to trigger transmission of SIB1 by cell 1.

[0113] Fig. 3 illustrates a method for requesting SIB1 directly from cell 1. 15

[0105] Fig. 4 illustrates a flowchart of an example method.

[0106] Fig. 5 illustrates a flowchart of another example method.

[0107] Fig. 6 illustrates a flowchart of another example method.

[0108] Fig. 7 illustrates a flowchart of another example method. Detailed description

[0109] When a UE is switched on, the UE searches for available cells and selects the most suitable cell according to cell selection criteria. The UE tunes to the control channels of the selected cell so that available services may be provided via the cell when required. The process of selecting the cell and tuning to the cell’s control channels may be referred to as "camping” on the cell.

[0110] When the UE is camped on the cell in idle mode, the UE is able to receive system information from the network. The UE is also able to receive cell broadcast messages.

[0111] The UE may search for more suitable cells at regular time intervals.

[0112] If the UE finds a more suitable cell, it may reselect the more suitable cell and tune to the control channels of the more suitable cell. By this process of cell reselection, the UE may camp on an alternative cell.

[0113] The UE may establish an RRC connection in order to configure radio resources and transition to “RRC Connected” state. RRC protocol is defined in 3GPP TS 38.331, which is herein incorporated by reference.

[0114] The UE may also perform network registration via the selected cell. Once registered, if the UE wishes to initiate a call, it can do so by initially accessing the network on the control channel of the cell on which it is camped. If the network receives a call for the registered UE, it can send a "paging" message for the UE on a control channel of the cell (and all other cells in the registration area). The UE will then receive the paging message because it is tuned to the control channel of the cell on which it is camped and the UE can respond on that control channel.

[0115] Cell search is performed when a UE connects to the base station and is used for time and frequency synchronisation and to detect a Physical layer Cell ID (PCI) of the cell. Cell search may be performed in a number of scenarios, such as: when the UE is powered on, during mobility in connected mode (handover), during idle or inactive mode mobility (cell reselection), and during inter-RAT mobility. Cell search is described in clause 4.1 of 3GPP TS 38.213, which is herein incorporated by reference.

[0116] When performing cell search, the UE uses a synchronisation signal block (SSB) to derive the necessary information required to access the cell.

[0117] In 5G(NR), a gNB periodically transmits a Signal Synchronisation Block (SSB), which is used by UEs for synchronisation, cell search and initial beamforming. The SSB is comprised of primary and secondary synchronisation signals (PSS and SSS) and physical broadcast channel (PBCH). The PBCH is comprised of physical broadcast channel demodulation reference signal (PBCH DMRS), which functions as a reference signal for decoding the PBCH, and payload data, which is used for transmitting the master information block (MIB).

[0118] The MIB may comprise information about reference subcarrier spacing, control channel for SIB PDSCH, DMRS position, and the like. SIB1 may carry all the basic information for UE to perform the initial attachment procedure (at least up to RRC Setup Request in RRC Connection Establishment). SIB1 may also carry scheduling information for other SIBs.

[0119] System Information (SI) in NR (also known as 5G) consists of a Master Information Block (MIB) and a plurality of numbered System Information Blocks (SIBs). The first SIB is called System Information Block One, SIB1. “System information block one” or “SIB1 ” are terms that are familiar to the skilled person in the field. This SIB1 may alternatively be referred to as a “first system information block”. The MIB and SIB1 together make up the “Minimum SI”. The SIB1 may also be referred to as Remaining Minimum SI, RMSI. All the other SIBs that are not included in the Minimum SI are collectively known as “Other SI”. Minimum SI carries the basic information required for initial access and for acquiring any other SI. For a UE to camp on a cell, it must first receive and decode the contents of the Minimum SI from that cell. SI requirements for UEs are further defined in clause 5.2.2.1 of 3GPPTS 38.331.

[0120] As it can be seen from the above, the reception of MIB and SIB1 is essential for all NR UEs independent of their additional capabilities and indeed the SIB1 includes information about the scheduling of other SIBs and other essential information.

[0121] Other SI consists of all SIBs not broadcast in the Minimum SI. The UE does not need to receive these SIBs before accessing the cell. In some examples, the SIBs forming the other SI can be broadcasted and scheduled with periodicity. The SIB1 may indicate which are available and provide the scheduling information. In other examples, the SIBs that make up the Other SI may also be known as On-Demand SI because gNB transmits / broadcasts these SIBs when explicitly requested by UE(s). The SIB1 may provide RACH configuration allowing the UE to request a particular SIB. By only transmitting SIBs when requested, network energy performance may be improved and signalling overhead in the cell may be reduced. When there are no UEs connected to the cell, the network may not need to transmit any of the SIBs in the Other SI.

[0122] By the methods disclosed in this application, the base station may also be able to avoid transmitting the SIB1 when not required. This may further improve network energy performance and reduce signalling overhead in the cell.

[0123] System information is further described in clause 5.2.1 of 3GPP TS 38.331. The SIB1 is transmitted on the DL-SCH with a periodicity of 160 ms and variable transmission repetition periodicity within 160 ms, as specified in clause 13 of 3GPP TS 38.213. The default transmission repetition periodicity of SIB1 is 20 ms. However the actual transmission repetition periodicity may be determined by network implementation. For SSB and CORESET multiplexing pattern 1, SIB1 repetition transmission period is 20 ms.

[0124] In some examples, the maximum size of SIB1 is about 3000 bits.

[0125] As described above, SIB1 is an essential SIB within a NR system. SIB1 must be received and decoded by the UE before declaring the cell as suitable. Nevertheless, periodic broadcast of SIB1 it contributes significantly to energy consumption of the base station. This is at least because SIB1 is sent periodically over the BCCH (broadcast channel) logical channel, which is mapped to PDSCH.

[0126] During the discussions of 3GPP release 19 content, there are a several proposals on how the SIB1 can be obtained using other frequencies. Two possible options are described below.

[0127] Fig. 1 illustrates a first option, in which SIB1 for cell 1 could be sent by cell 2. In this way, the UE would be able to access cell 1, once the cell reference signals can be measured and MIB from the cell 1 is received. SIB1 for Cell 1 may be sent to Cell 2 via the X2 / Xn interface.

[0128] Fig. 2 illustrates a second option, in which the UE, under the coverage of cell 2, could request cell 2 to trigger the transmission of SIB1 from the cell 1. The request to trigger SIB1 transmission for Cell 1 may be sent from Cell 2 to Cell 1 via the X2 / Xn interface.

[0129] Figs. 1 and 2 illustrate examples where the base stations corresponding to cell 1 and cell 2 are non-collocated. However the same procedures could apply where the base stations are collocated. For example, Cell 1 could be for a higher frequency band (capacity layer) and Cell 2 for a lower frequency band (coverage layer).

[0130] The solutions illustrated in Figs. 1 and 2 are suitable in scenarios where there is overlapping cell coverage. However, if there is no overlapping coverage, the UE could not use either of these methods to request the SIB1 from the system. Fig. 3 illustrates an alternative solution that is suitable even when the UE is not within coverage of any other cell. As illustrated in Fig.3, the UE requests SIB1 directly from cell 1.

[0131] Normally, the UE would not be able to send a request to Cell 1 without first acquiring SIB1 for that cell. However, the present disclosure provides means for the UE to send the request to Cell 1, even though Cell 1 is not currently broadcasting SIB1. One aim of this solution is to introduce a mechanism which would allow single carrier on demand SIB operation.

[0132] As defined in 3GPP TS 38.331, the UE receives the MIB and decodes a number of parameters from the MIB, including the pdcch-configSIB IE. — ASNlSTART — TAG-MIB-START MIB ::= SEQUENCE { systemFrameNumber BIT STRING (SIZE (6)), subCarrierSpacingCommon ENUMERATED {scsl5or60, scs30orl20}, ssb-SubcarrierOffset INTEGER (0..15), dmrs-TypeA-Position ENUMERATED {pos2, pos3}, pdcch-ConfigSIBl PDCCH-ConfigSIBl, cellBarred ENUMERATED {barred, notBarred}, intraFreqReselection ENUMERATED {allowed, notAllowed}, spare BIT STRING (SIZE (1)) — TAG-MIB-STOP — ASN1STOP

[0133] The pdcch-ConfigSIB1 IE defines a ControlResourceSet (CORESET), a common search space and necessary PDCCH parameters. — ASNlSTART — TAG-PDCCH-CONFIGSIB1-START PDCCH-ConfigSIBl ::= SEQUENCE { ControlResourceSetZero ControlResourceSetZero, searchSpaceZero SearchSpaceZero } — TAG-PDCCH-CONFIGSIB1-STOP — ASN1STOP

[0134] If the field ssb-SubcarrierOffset indicates that SIB1 is absent, the field pdcch-ConfigSIBI indicates the frequency positions where the UE may find a SS / PBCH block with SIB1 or the frequency range where the network does not provide SS / PBCH block with SIB1.

[0135] Therefore, the ssb-SubcarrierOffset IE can be used to indicate that SIB1 is not present. However, according to prior art UE and network behavior defined in clause 5.2.2.3.1 of 3GPP TS 38.331, if there is no information provided for where the UE may find a SS / PBCH block with SIB1, the UE would be required to act according to clause 5.2.2.5 of 3GPP TS 38.331 and bar the cell. Likewise, if the UE is unable to acquire the SIB1, the UE would consider the cell as barred in accordance with 3GPP TS 38.304, which is herein incorporated by reference. Disabling SIB1

[0136] In contrast to prior art methods, the present disclosure provides methods that allow the cell to stop broadcasting SIB1, even there is no prior knowledge of the overlayed cells in the area of consideration. In other words, the cell may disable SIB1 broadcast, even if this would leave a coverage hole.

[0137] Prior to disabling broadcast of SIB1, the cell should inform the UEs in the coverage area that the cell is going to stop broadcasting the SIB1 and give the UEs an opportunity to request that broadcast of SIB1 continues. The UE may request that the gNB not disable broadcast of SIB1 as doing so might result in a loss of coverage for the UE.

[0138] It may be seemingly undesirable for the network operator to potentially create coverage holes. However, it may be useful to disable SIB1 for a cell if there are no UEs in the coverage area. This is at least because disabling SIB1 reduces energy consumption of the base station and SIB1 may be re-activated when the cell is needed again. One example of where this solution may be advantageous is for indoor coverage where a cell is set up to serve UE of employees in an office building. People may leave the building in the evening and come back in the morning. During the night, coverage inside the building is not required, even though the coverage provided by outdoor antennas might not be present in all indoor locations.

[0139] In a first step, the base station that intends to stop broadcasting SIB1 should inform UEs under its coverage that broadcast of SIB1 is scheduled to be disabled. This indication can be provided to the UEs via a dedicated bit / information in SIB1 or via other means, such as using information within the MIB. In one example, the pdcch-ConfigSIB1 IE in the MIB may be set to provide this indication to the UEs. In another example, the spare bit in the MIB may be used as an indication.

[0140] As described above, the indication that the base station (e.g., nodeB) intends to stop broadcasting SIB1 may be provided via the MIB or the SIB1.

[0141] The indication that SIB1 broadcast is about to stop may be provided implicitly via a combination of parameters in the MIB. In one example, the indication of intention to stop may be indicated via a combination of pdcch-ConfigSIB1 and ssb-SubcarrierOffset lEs. In another example the indication may be provided via the spare bit in the MIB. The MIB cannot be extended further. Therefore, use of the remaining spare bit may lead to problems in the future. Therefore, it is preferable to provide the indication via preexisting parameters in the MIB.

[0142] In a second step, if there are UEs within the coverage area (for example, one or more UEs in RCC Idle or Inactive mode, still monitoring the base station) and such an indication is received, the UEs should inform the base station about their presence. In one example, the UE may use resources provided within SIB1 for other SI requests to indicate to the base station that the UE still requires SIB1. There are also other ways that the UE may indicate to the base station that SIB1 is required. In another example, the UE may use pre-configured resources (as explained in further detail in the third step of the method for re-activating SIB1) to send a RACH preamble to the base station. In some examples, the UE will indicate that it still requires SIB1 by requesting a SIB from the base station using the SI-Request_Config IE.

[0143] In other words, compatible UEs may detect the indication and inform the base station of their presence within the cell, using resources configured in SIB1.

[0144] The base station will broadcast the indication for a period of time and await a response from any UEs in the coverage area. If the base station receives a RACH preamble from a UE during that period, it will interpret the RACH preamble received as an answer as a presence of the UE in the cell. Therefore, the base station will stop broadcasting the indication that periodic broadcast of the SIB1 is scheduled to be disabled. Therefore, the base station will decide not to disable SIB1 and will continue periodic broadcast of SIB1.

[0145] In other words, if the base station notes the presence of a UE camped on the cell, it will decide to continue broadcasting SIB1, removing the indication mentioned above.

[0146] Otherwise, if the base station does not receive any indication form a UE during the predetermined period of time, the base station may disable SIB1 broadcast.

[0147] Non-compatible equipment camped on the cell may not discern the meaning of the indication broadcast by the base station. Such a UE may therefore not respond during the predetermined period. Therefore, the base station will disabled SIB1 broadcast. Once SIB1 is no longer broadcast, the UE will bar the cell. Re-activating SIB1

[0148] Where the base station is not broadcasting SIB1 and a UE is in the coverage area of the cell, the UE may need to request that the cell re-activates broadcast of SIB1. This scenario may occur where a UE enters the coverage area of the cell (and leaves the coverage area of a previous serving cell) or is switched on in the coverage area of the cell. In either case, the UE will attempt to (re)select the cell. This might be due to someone returning to the office in the previous example.

[0149] In a first step, the UE determines (e.g., from the MIB) that SIB1 is not being broadcast by the cell. In order for the UE to determine that SIB1 broadcast is disabled, the spare bit of the MIB broadcast by the base station could be used for the base station to indicate that SIB1 is disabled. Alternatively, the ssb-SubcarrierOffset IE may be set to indicate that no SIB1 is being broadcast, by reporting the “noSIBI” indication as specified in clause 6.3.2 of 3GPP TS 38.331 (in a manner similar to the determination that SIB1 is absent during carrier aggregation).

[0150] If the value of the subcarrier offset, kSSn (determined from the ssb-SubcarrierOffset IE) is more than 23 (for FR1), idle UEs according to prior art behaviour would bar the cell. However, UEs supporting the features and methods described herein may interpret this value of subcarrier offset to mean that SIB1 is currently disabled and can be re-activated. Therefore, rather than immediately barring the cell, a UE may use the proposed methods to re-activate SIB1 broadcast.

[0151] In a second step, the UE may identify a search space that the UE would need to monitor once SIB1 is broadcast. The search space may be determined from the pdcch-ConfigSIBI IE.

[0152] The MIB broadcast by the space station may define the search space in pdcch-ConfigSIBI, even while SIB1 is not being broadcast. A prior art UE may interpret the search space defined in pdcch-ConfigSIB1 as a search space where a SIB1 is not being broadcast. A UE supporting the features and methods described herein may interpret the search space defined in pdcch-ConfigSIB1 as a search space where a SIB1 is not currently being broadcast but where it will be broadcast once SIB1 is enabled. In this way, the UE may obtain the search space ahead of time while the SIB1 is still disabled.

[0153] Alternatively, once SIB1 is being broadcast, the base station may update the MIB. The updated MIB would include updated parameters (such as the subcarrier offset and / or the spare bit) to indicate that SIB1 is being broadcast. At this time, the pdcch-ConfigSIB1 IE may also be updated to identify a search space. The UE may determine the search space from the pdcch-ConfigSIB1 IE in the updated MIB.

[0154] In a third step, the UE determines valid configuration (e.g., RACH configuration) for sending a message to the base station. Once the valid configuration has been determined, the UE may use the configuration to request that the base station activate broadcast of SIB1 (and not bar the cell).

[0155] As with prior art techniques, the valid configuration may be defined by the Sl-RequestConfig IE. The configuration may be needed to establish uplink synchronisation. Therefore, the UE may be unable to send requests to the base station without the configuration (and therefore unable to request the configuration form the base station).

[0156] In prior art methods, the UE obtains RACH configuration from the SIB1. Therefore, when SIB1 is not being broadcast, the UE must obtain the configuration another way.

[0157] The valid configuration may be a basic version of the configuration that is sufficient to send a RACH preamble on the PRACH channel. The configuration may be standardized in a number of ways, as will be described below.

[0158] In one option, the configuration may be provided to the UE ahead of time (e.g. OTT, during the manufacturing process or by other means). The configuration would also indicate the frequency to which it would apply (currently this information is not provided). The configuration for re-activating SIB1 broadcast may be standardized across all cells having this option, so that the UE can use the predetermined configuration for this purpose.

[0159] In another option, the configuration may be selected from a number of predetermined configurations. The configuration may be selected based on information provided to the UE during the attach procedure.

[0160] In yet another option, the configuration (for sending a message to the cell not currently broadcasting SIB1 “Cell A”) may be provided to the UE by another cell (“Cell B”), at a moment in time before the UE is within the coverage area of Cell A (the cell to which the configuration applies). The UE may store the configuration in association with an identifier of Cell A. When the UE determines that SIB1 is disabled for Cell A, it may retrieve previously stored configuration corresponding to Cell A and use the stored configuration to send a request to the base station associated with Cell A and not bar the cell. Since the proposed methods are suitable for scenarios where there is no overlapping coverage, the configuration must be obtained ahead of time and stored by the UE (unlike the example illustrated in Fig. 1, in which the UE benefits from overlapping coverage and obtains the SIB1 from an alternative cell).

[0161] The proposed methods may be used where overlapping coverage is present. However, it is an objective of the proposed methods that this is not required and the methods should therefore work where there is no overlapping coverage.

[0162] When the UE is connected to Cell B, the Cell B may indicate to the UE that if the UE detects a particular cell (Cell A), and SIB1 is not being broadcast, then the configuration provided by Cell B may be used to request that Cell A re-activate broadcast of SIB1.

[0163] In some examples, the base station associated with Cell A and Cell B may be colocated. In some examples, Cell A and Cell B may be operating on different frequency bands (e.g. Cell A may be operating at 700 MHz while Cell B is operating at 3.5 GHz).

[0164] In a fourth step, the UE requests SIB1 to be broadcasted by the system. The UE may send this request to the base station using via the SI-RequestConfig information element.

[0165] Incompatible UEs would determine that SIB1 is not being broadcast and would bar the cell. For these UEs, there is no mechanism for reactivating SIB1.

[0166] Once broadcast of SIB1 is re-activated, the MIB may be modified to provide some parameters for receiving and decoding SIB1.

[0167] From release 19 of the 3GPP technical standards, all the information required to receive and decode the SIB1 may be provided in the MIB.

[0168] As previously discussed, legacy UEs that cannot read SIB1 will declare the cell as barred. These UEs will continue to look for cells on the same frequency or look for cells on other frequencies. SIB1 may therefore be selectively deactivated for base stations that are not critical for providing coverage (e.g., in an office building).

[0169] In a future iteration of the standards (e.g., 6G) the proposed methods may be mandated. Therefore, it may be relied upon that every UE is capable of requesting SIB1 reactivation. In this case, selective deactivation of SIB1 may be applied more widely to base stations, since reactivation of SIB may be reliably requested when it is needed. These methods may therefore be used across many base stations to provide network power savings, without compromising network coverage.

[0170] Fig. 4 illustrates a flowchart of an example method of controlling a base station in a telecommunications network to disable or continue periodic broadcast of a system information block one, SIB1. The method comprises: at step 401: broadcasting an indication that periodic broadcast of the SIB1 is scheduled to be disabled; at step 402: either: a) receiving, from a User Equipment, UE, an indication that the UE requires periodic broadcast of the SIB1; or b) determining that no indication that a UE requires periodic broadcast of the SIB1 has been received during a predetermined period of time; at step 403: controlling the base station to continue periodic broadcast of the SIB1; and at step 404: controlling the base station to disable periodic broadcast of the SIB1.

[0171] Fig. 5 illustrates a flowchart of an example method of controlling a base station in a telecommunications network to activate periodic broadcast of a system information block one, SIB1. The method comprises: at step 501: receiving, from a User Equipment, UE, an indication that the UE requires periodic broadcast of the SIB1; and at step 502: controlling the base station to activate periodic broadcast of the SIB1.

[0172] Fig. 6 illustrates a flowchart of an example method of a User Equipment, UE, communicating with a base station in a telecommunications network to prevent the base station from disabling periodic broadcast of a system information block one, SIB1. The method comprises: at step 601: receiving an indication that periodic broadcast of the SIB1 is scheduled to be disabled; and at step 602: sending to the base station an indication that the UE requires periodic broadcast of the SIB1.

[0173] Fig. 7 illustrates a flowchart of an example method of a User Equipment, UE, communicating with a base station in a telecommunications network to cause the base station to activate periodic broadcast of a system information block one, SIB1. The method comprises: at step 701: determining that periodic broadcast of the SIB1 is disabled; and at step 702: sending, to the base station, an indication that the UE requires periodic broadcast of SIB1.

[0174] Any of the methods described herein may be implemented as a computer program. The computer program may be configured to control a RAN entity (e.g., a network node) and / or UE to perform any method according to the disclosure. A RAN entity (e.g., a network node) of a cellular network and / or a UE may also be provided, configured to operate in accordance with certain methods disclosed herein. For example, the RAN entity may include a processor and at least one communication interface, particularly comprising one or both of a transmitter and receiver. A UE may also be provided, configured to operate in accordance with certain methods disclosed herein. The UE may likewise include a processor and at least one communication interface, particularly comprising one or both of a transmitter and receiver.

[0175] Although specific embodiments have now been described, the skilled person will understand that various modifications and variations are possible. For example, whilst the disclosure is described in relation to existing network architecture, it will be understood that changes to the architecture (and / or nomenclature) are possible, but the present disclosure may still be applicable in this case. Also, combinations of any specific features shown with reference to one embodiment or with reference to multiple embodiments are also provided, even if that combination has not been explicitly detailed herein.

[0176] A base station (BS) generally refers to a fixed station that performs communication with a UE and / or another BS, and exchanges various kinds of data and control information with the UE and another BS. The BS may be referred to as an advanced base station (ABS), a base transceiver station (BTS), a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), an access point (AP), a Node B (NB), an eNode B (eNB), a gNode B (gNB), a transmission and reception point (TRP), a processing server (PS), or some other suitable terminology, depending on the protocol, standard, context or technology. In some examples, a base station may include two or more transceivers that may or may not be collocated. Each transceiver may communicate on the same or different carrier frequency within the same or different frequency band.

[0177] Where this application refers to a server or network entity, for instance, this may actually be a pair of servers, or network entities (primary and failover), for redundancy.

[0178] In the present invention, a node refers to a fixed point capable of transmitting / receiving a radio signal through communication with a UE. Various types of base stations (such as those described above) may be used as nodes, irrespective of the terms used. In other examples, a node may be a relay, a repeater, and the like.

[0179] In the present invention, a UE may be a fixed or mobile device. Examples of the UE include various devices that transmit and receive user data and / or various kinds of control information to and from a base station. The UE may be referred to as a terminal equipment (TE), a mobile station (MS), a mobile terminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, a personal digital assistant (PDA), a wireless modem, a handheld device, etc.

[0180] Whilst the above methods are described in relation to a 5G / NR network, these methods, techniques, apparatuses, and systems may be applied to a variety of wireless multiple access systems. Examples of multiple access systems include CDMA, FDMA, TDMA, OFDMA, SC-FDMA, and MC-FDMA. CDMA may be embodied through radio technology such as LITRA or CDMA2000. TDMA may be embodied through radio technology such as GSM, GPRS, or EDGE. OFDMA may be embodied through radio technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or E-LITRA. UTRA is a part of a UMTS. 3GPP LTE is a part of E-UMTS using E-UTRA. 3GPP LTE employs OFDMA in DL and SC-FDMA in UL. LTE-A is an evolved version of 3GPP LTE. 3GPP NR employs OFDMA for both downlink and uplink and can operate in both FDD and TDD. For convenience of description, it is assumed that the present invention is applied to 3GPP NR. However, the technical features of the present invention are not limited thereto. For example, although the following detailed description is given based on a mobile communication system corresponding to a 3GPP NR system, aspects of the present invention that are not specific to 3GPP NR are applicable to other mobile communication systems. Moreover, the technical features of the present invention may be applied to future iterations of multiple access systems defined in 3GPP standards, such as (but not limited to) 6G.

[0181] In the present disclosure, a cell refers to a geographical area to which one or more nodes provide a communication service. Accordingly, in the present disclosure, communicating with a specific cell may mean communicating with an gNB or a node which provides a communication service to the specific cell. Furthermore, channel status / quality of a specific cell refers to channel status / quality of a channel or communication link formed between an gNB or node which provides a communication service to the specific cell and a UE. The UE may measure DL channel state received from a specific node using cellspecific reference signal(s) (CRS(s)) transmitted on a CRS resource and / or channel state information reference signal(s) (CSI-RS(s)) transmitted on a CSI-RS resource, allocated by antenna port(s) of the specific node to the specific node. Meanwhile, a 3GPP system uses the concept of a cell in order to manage radio resources and a cell associated with the radio resources is distinguished from a cell of a geographic region.

[0182] The examples may be carried out on any suitable data processing device, such as a personal computer, laptop, mobile telephone, server, virtual machine, and the like. The above description of the systems and methods has been simplified for purposes of discussion, and is intended to provide a specific example to illustrate the invention. Different types of systems and methods may be used, as will be appreciated by the skilled person. It will be appreciated that the boundaries between logic blocks are merely illustrative and that alternative embodiments may merge logic blocks or elements, or may impose an alternate decomposition of functionality upon various logic blocks or elements.

[0183] It will be appreciated that the above-mentioned functionality may be implemented as one or more corresponding modules as hardware and / or software. For example, the above-mentioned functionality may be implemented as one or more software components for execution by a processor of the system. Alternatively, the above-mentioned functionality may be implemented as hardware, such as on one or more FPGAs, and / or one or more ASICs, and / or one or more DSPs, and / or other hardware arrangements. Method steps implemented in flowcharts contained herein, or as described above, may each be implemented by corresponding respective modules. Moreover, multiple method steps implemented in flowcharts contained herein, or as described above, may be implemented together by a single module.

[0184] Examples may be implemented by computer software or a “computer program.” A storage medium and a transmission medium carrying the computer program are also provided. The computer program may comprise one or more instructions, or code, that, when executed by a computer, causes the methods described to be performed. A computer program may be a sequence of instructions designed for execution on a computer system, and may include a subroutine, a function, a procedure, a module, an object method, an object implementation, an executable application, an applet, a servlet, source code, object code, a shared library, a dynamic linked library, and / or other sequences of instructions designed for execution on a computer system. The storage medium may be a magnetic disc (such as a hard drive or a floppy disc), an optical disc (such as a CD-ROM, a DVD-ROM, or a Blu-ray disc), or a memory (such as a ROM, a RAM, EEPROM, EPROM, Flash memory or a portable / removable memory device), etc. The transmission medium may be a communications signal, a data broadcast, a communications link between two or more computers, etc.

[0185] Each feature disclosed in this specification, unless stated otherwise, may be replaced by alternative features serving the same, equivalent, or similar purpose. Thus, unless stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0186] As used herein, including in the claims, unless the context indicates otherwise, singular forms of the terms herein are to be construed as including the plural form and vice versa. For instance, unless the context indicates otherwise, a singular reference herein including in the claims, such as "a" or "an" (such as a UE, a node, a network entity, a RAN entity, or a cell) means "one or more” (for instance one or more UE, one or more nodes, one or more network entities, one or more RAN entities, or one or more cells). Throughout the description and claims of this disclosure, the words "comprise", "including", "having" and "contain" and variations of the words, for example "comprising" and "comprises" or similar, mean "including", and are not intended to (and do not) exclude other components.

[0187] The use of any and all examples, or exemplary language ("for instance", "such as", "for example" and like language) provided herein, is intended merely to better illustrate the invention, and does not indicate a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any nonclaimed element as essential to the practice of the invention.

[0188] Any steps described in this specification may be performed in any order or simultaneously unless stated or the context requires otherwise. Moreover, where a step is described as being performed after a step, this does not preclude intervening steps being performed.

[0189] All of the aspects and / or features disclosed in this specification may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. As described herein, there may be particular combinations of aspects that are of further benefit, such the aspects of determining a set of compensation parameters and applying a set of compensation parameters to measurements. In particular, the preferred features of the invention are applicable to all aspects of the invention and may be used in any combination. Likewise, features described in nonessential combinations may be used separately (not in combination).

[0190] A method of manufacturing and / or operating any of the devices disclosed herein is also provided. The method may comprise steps of providing each of the features disclosed and / or configuring or using the respective feature for its stated function. 22 01 26

Claims

1. A method of configuring a user equipment, UE, in a telecommunications network, the method comprising:5 sending, from an alternative base station to the UE, configuration corresponding toa target base station, wherein the configuration is for sending an indication to the target base station that the UE requires periodic broadcast of a system information block one, SIB1, from the target base station.10 2. The method of claim 1, wherein sending the configuration comprises sending asystem information block one, SIB1, corresponding to the base station, wherein the SIB1 corresponding to the base station comprises the configuration corresponding to the target base station.15 3. The method of claim 1 or claim 2, wherein the configuration is sent to the UE at afirst point in time and wherein the UE is configured to send the indication that periodic broadcast of SIB1 is required to the target base station at a second point in time later than the first point in time, wherein the UE is not in communication with the base station at the second point in time.

204. The method of any preceding claim, wherein the base station is a different cell entity to the target base station.

5. A method of a telecommunications network controlling a target base station to 25 activate periodic broadcast of a system information block one, SIB1, the method comprising:configuring, by the method of any of claims 1 to 3, a User Equipment, UE, via an alternative base station;receiving by the target base station, from the UE, an indication that the UE requires 30 periodic broadcast of the SIB1 from the target base station; andcontrolling the target base station to activate periodic broadcast of the SIB1.

6. The method of claim 5, further comprising:broadcasting, by the target base station, a master information block, MIB,22 01 26wherein the MIB comprises an indication that periodic broadcast of the SIB1 is disabled.

7. The method of claim 6, wherein the indication that periodic broadcast of the SIB1 is5 disabled is provided by one or more of:a spare bit in the MIB;a subcarrier offset, kSSb, that is defined by one or more of:a ssb-SubcarrierOffset information element in the MIB; andone or more additional bits of data provided in a physical broadcast channel, 10 PBCH, payload;a subcarrier spacing;a search space, SearchspaceO; anda control resource set, CORESET0.15 8. A method of a User Equipment, UE, communicating with a target base station in atelecommunications network to cause the target base station to activate periodic broadcast of a system information block one, SIB1, the method comprising:determining configuration for sending an indication to the target base station, by receiving, from an alternative base station, configuration corresponding to the target base 20 station;determining that periodic broadcast of the SIB1 by the target base station is disabled; andsending, to the target base station, an indication that the UE requires periodic broadcast of SIB1.

259. The method of claim 8, wherein the indication that the UE requires periodic broadcast of the SIB1 comprises a request for a system information block.

10. The method of claim 8 or claim 9,30 wherein receiving configuration corresponding to the target base station comprisesreceiving, from the alternative base station, a system information block one, SIB1, corresponding to the alternative base station, wherein the SIB1 corresponding to the alternative base station comprises the configuration corresponding to the target base station.3522 01 2611. The method of any of claims 8 to 10, wherein the configuration is received from the alternative base station at a first point in time and wherein the UE sends the indication that periodic broadcast of SIB1 is required at a second point in time later than the first point in time, wherein the UE is not in communication with the alternative base station at the5 second point in time.

12. The method of any of claims 8 to 11, wherein the configuration comprises random access channel, RACH, configuration.10 13. The method of any of claims 8 to 12, wherein determining that periodic broadcast ofthe SIB1 is disabled comprises receiving and decoding a master information block, MIB, from the base station, wherein the MIB comprises an indication that periodic broadcast of the SIB1 is disabled.15 14. The method of claim 13, wherein the indication that periodic broadcast of the SIB1is disabled is provided by one or more of:a spare bit in the MIB;a subcarrier offset, kSSb, that is defined by one or more of:a ssb-SubcarrierOffset information element in the MIB; and20 one or more additional bits of data provided in a physical broadcast channel,PBCH, payload;a subcarrier spacing;a search space, SearchspaceO;a control resource set, CORESET0;25 a pdcch-ConfigSIB1 information element in the MIB; andone or more other parameters in the MIB.

15. The method of any of claims 8 to 14, further comprising: determining a search space;30 monitoring the search space; andreceiving and decoding the SIB1.

16. The method of claim 15, further comprising: receiving and decoding an updated MIB,wherein receiving and decoding the SIB1 comprises using updated parameters in the updated MIB to receive and decode the SIB1.

17. A base station configured to perform the method of any of claims 1 to 4.

518. A telecommunications network configured to perform the method of any of claims 5to 7.

19. A User Equipment, UE, configured to perform the method of any of claims 8 to 16.1020. A computer program comprising instructions that, when executed on a processor, cause the processor to perform the method of any of claims 1 to 16.22 01 26

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