OA18275A - Methods and apparatus for verifying system information. - Google Patents

Abstract

The present invention relates to a method performed by a wireless device. The wireless device is configured with information associated with at least one of the wireless device and one or more wireless communication networks to which the wireless device is connectable. The method comprises determining (310) a device hash code based on the configured information in the wireless device. The method also comprises determining (320) whether the configured information in the wireless device needs to be updated based on the device hash code and an exchange of information with a network node of a wireless communication network. The present invention also relates to a corresponding method performed by the network node, as well as the wireless device and the network node.

Description

METHODS AND APPARATUS FOR VERIFYING SYSTEM INFORMATION

TECHNICAL FIELD

The disclosure relates to vérification of system Information configured in a wireless device, and more specifically to methods and apparatus for determining whether information configured in a wireless device needs to be updated.

BACKGROUND

Long Term Evolution (LTE) is the fourth-generation (4G) mobile communication technologies standard developed within the 3^ Génération Partnership Project (3GPP) to improve the Universal Mobile Télécommunication System (UMTS) standard to cope with future requirements In terms of improved services such as higher data rates, Improved efficiency, and lowered costs. The Universal Terrestrial Radio Access Network (UTRAN) is the Radio Access Network (RAN) of a UMTS and Evolved UTRAN (E-UTRAN) is the RAN of an LTE system. In an E-UTRAN, a User Equipment (UE) Is wirelessly connected to a Radio Base Station (RBS) commonly referred to as an evolved NodeB (eNodeB or eNB) In LTE. An RBS is a general term for a radio network node capable of transmitting radio signais to a UE and receiving signais transmitted by a UE.

Figure 1 illustrâtes a conventional RAN In an LTE system. An eNodeB 101 serves a UE 103 located within the eNodeB’s geographical area of service also sometimes called a cell. The eNodeB 101 manages the radio resources in its cell and is directly connected to a Core Network (CN) 105. The eNodeB 101 may also be connected via an X2 Interface to a neighboring eNodeB serving another cell.

A new system concept initially designed for frequencies above 6 GHz is developed to meet the future 5G requirements. One proposai for this new system is to logically separate the data transmissions from the system plane functionality. For the purpose of enabling high network energy performance or lower energy consumption per area unit, high adaptability, high peak throughput, and forward compatibîlity the design of the new system should be as lean as possible, meaning that the amount of mandatory transmissions from idle network nodes should be minimlzed. One proposai is to transmit a system signature sequence from nodes e.g. every 100 ms. The UEs could then dérivé the access Information from this sequence by means of a table look-up. The actual table containing the access Information could e.g. be transmitted very seldom, e.g. every 10,24 seconds, or be encoded on a SIMcard. This access information could also be used In multiple Systems.

In the new system concept there is a distinction between access Information and system information. Access Information dénotés the information required to access the network, i.e.

• Information such as Random Access Channel (RACH) configuration and open-loop power control parameters. Therefore, the term system information is hereinafter used to dénoté all other non-initial access related information that the UE may need to know, i.e. information about how the system is configured such as cell re-selection parameters, paging configuration, parameters related to positioning, and Inter Radio Access Technology (IRAT) neighbors.

Multiple stake-holders and Systems

A 5G system will among other things be characterized by high capacity, high throughput, Indoor deployment, high frequency bands, and short range. In many 5G-related scénarios the traditional cellular operators will not be the only stake-holder, rather many Systems and configurations are used to fulfill the user requirements. Venue owners such as hôtels, malls, train companies, and stadiums typically buiîd Wireless Local Area Networks (WLANs) today since they don’t hâve a SIM-card relation to their customers, i.e. their customers hâve no subscription offered by them. Operators on the other hand that offer the subscriptîons cannot deploy 3GPP based technologies in many of these areas since they may not always hâve the required location access. Two examples of multi-stakeholder use cases are:

• A hôtel owner building a small Indoor network wanting to integrate with all outdoor macro networks.

• A macro operator wanting to provide improved performance for its subscribers by utilizing 1000 strategically located small cells deployed by a sub-way company.

Currently the network évolution is hindered by lack of multi-stakeholder support. In 4G or earlier générations of wireless networks this has been acceptable. However, in a 5G context where requirements will force the network rollout to include also indoor areas this will likely become a major problem to address.

Multiple system and access technologies

When Introducing a new génération the existing Systems from earlier générations are typically not replaced. Hence multiple technologies are likely to be used in the future. These multiple Systems need to be configured with system information, a configuration that Is either signaled to the wireless devices or UEs using a system broadcast or using dedicated signaling. The time needed for such signaling of system information Is often too large to facilitate session seamless handover between different Systems and technologies.

System time acquisition ,

Another reason for a wireless device or a UE to read the system broadcast of a system Is to acquire the sub-frame number (SFN) of the system. The signaling of the SFN can be quite 5 Infrequent which may hence delay a UE when accessing the system.

System access acquisition

UEs also need to read the system broadcast of a system in order to acquire the means and rights to access a system. In case of heavy load it can be bénéficia! to Instruct UEs with lower priority to delay their access. This is especially true if the access is triggered 10 synchronously by an event, e.g. a spécifie time of day, or based on sensor measurements, e.g. multiple movement sensors on a bridge.

SUMMARY

It is therefore an object to address some of the problème outlined above, and to provide a solution for enabling a fast system access. This object and others are achieved by the 15 methods and the apparatus according to the Independent claims, and by the embodiments according to the dépendent claims.

In accordance with a first aspect, a method performed by a wireless device is provided. The wireless device is configured with information associated with at least one of the wireless device and wireless communication networks to which the wireless device is connectable.

The method comprises determining a device hash code based on the configured information in the wireless device. The method also comprises determining whether the configured Information in the wireless device needs to be updated based on the device hash code and an exchange of information with a network node of a wireless communication network.

In accordance with a second aspect, a method performed by a network node of a wireless communication network is provided. The network node Is configured with information associated with the wireless communication network. The method comprises determining a network hash code based on the configured information In the network node. The method further comprises directing Information which is based on the network hash code to a wireless device, the information enabling the wireless device to détermine whether 30 configured information in the wireless device needs to be updated.

In accordance with a third aspect, a wireless device is provided. The wireless device is configured with information associated with one of the wireless device and wireless communication networks to which the wireless device is connectable, The wireless device is further configured to détermine a device hash code based on the configured information in the wireless device. The wireless device is also configured to détermine whether the 5 configured information In the wireless device needs to be updated based on the device hash code and an exchange of information with a network node of a wireless communication network.

In accordance with a fourth aspect, a network node for operation In a wireless communication network is provided. The network node Is configured with information 10 associated with the wireless communication network. The network node is further configured to détermine a network hash code based on the configured information in the network node, and direct Information which Is based on the network hash code to a wireless device. The information enables the wireless device to détermine whether configured information in the wireless device needs to be updated.

In accordance with further aspects, a first computer program Is provided. The first computer program comprises computer readable code which when run on a wireless device causes the wireless device to perform a method in accordance with the first aspect above. A first computer program product is also provided comprising a computer readable medium and the first computer program stored on the computer readable medium. Furthermore, a second 20 computer program is provided. The second computer program comprises computer readable code which when run on a network node causes the network node to perform a method in accordance with the second aspect above. A second computer program product is also provided comprising a computer readable medium and the second computer program stored on the computer readable medium.

An advantage of the different aspects above is that a faster system connection procedure Is allowed in many cases. For a wireless device that is idle and about to connect to a network, the network does not always need to wait for the configuration of new system information In the wireless device, as it may be determined that the wireless device is up to date and needs no new configuration information to be able to access the network. The same applies In cases when wireless devices move between networks that are not connected with a fast backhaul and therefore share system information on a slow basis, such as when the two networks may both be accessed by the wireless device although they do not share Core Network functionality.

Other objects, advantages and features of embodiments will be explaïned in the following detaiîed description when considered in conjunction with the accompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic illustration of an LTE network.

Figure 2a Is a flowchart illustrating one embodiment of the présent Invention.

Figures 2b-c are signaling diagrams Illustrating the signaling between network and wireless device according to some embodiments of the présent invention.

Figures 3a-d are fiowcharts illustrating the method in the wireless device according to some embodiments of the présent Invention.

Figures 4a-c are fiowcharts illustrating the method in the network node according to embodiments.

Figures 5a-b are block diagrams schematically illustrating the wireless device and the network node according to embodiments.

DETAILED DESCRIPTION

In the following, different aspects will be described In more detail with references to certain embodiments and to accompanying drawings. For purposes of explanation and not limitation, spécifie details are set forth, such as particular scénarios and techniques, in order to provide a thorough understanding of the different embodiments. However, other embodiments that départ from these spécifie details may also exist.

Embodiments are described In a non-limiting general context in relation to an example scénario in a wireless communication network, where a wireless device, sometimes referred to as a UE, is communicating with an RBS of the wireless communication network. It should be noted that the embodiments may be applied to any network technology in which a wireless device is configured with information related to a network before accessing or connecting to the network. Furthermore, the wireless device may in other example scénarios be communicating with other network nodes via the RBS, such as with another radio network node, a core network node, or a system management node. Examples of wireless devices are personal computers such as taptop computers and netbook computers, portable téléphoné communications devices such as smart phones, tablets, and Machine-TypeCommunication (MTC) devices.

A typical UE often has up to date system information for a network configured In the UE’s system information table when it attempts to access the network, although the network has no knowledge about it. Today there is no way for the network to verify stored system information In conventional UEs. Therefore the network configures the UE with system Information needed for the access to the network, which introduces both overhead and delay. In future Systems where system Information can be configured through many paths and where very long discontinuous transmission/reception cycles are enabled, the problem related to delay may become even bigger.

By checking, as in embodiments of the présent invention, whether the configured Information In the UE is up to date Instead of actually configuring the UE with the information, both overhead and deîay can be reduced. In embodiments of the invention, the problem of delays at access which is due to the configuration of information in the wireless device is addressed by a solution where hash codes are determined both in the wireless device and in a node of the wireless communication network that the wireless device wants to access or connect to. On both sides the hash code is determined based on configured Information in the wireless device and In the network node respectively. The hash code determined by the wireless device ls hereinafter referred to as the device hash code, and the hash code in the network node ls referred to as the network hash code. The hash codes are used to verify whether information configured in the wireless device needs to be updated or not. An exchange of information between the wireless device and the network node ls needed for the vérification, where the exchange Involves the device hash code and the network hash code. The exchange of Information may be performed in different ways depending on the embodiment, as will be described below.

A hash function is any function that can be used to map input digital data of arbitrary size to output digital data of fixed size, designed such that even a slight différence in input data produces, with very high probability, a different output data. The output data may be referred to as a hash code. The configured information in the wireless device may thus be used as Input data to a hash function used to détermine the device hash code. Correspondingly, information associated with the wireless communication network and configured in the network node may be used as input to the same hash function to détermine the network hash code. A hash code may sometimes also be referred to as a check sum or a cyclic redundancy check (CRC).

In embodiments of the invention, hash codes derived for configured system Information are used to enable fast System access for a UE and to reduce overhead related to the distribution of system Information. It is only In the case of a failed device hash code vérification that the extra overhead and/or latency of system Information acquisition Is needed. By letting the UE make immédiate access to an RBS after a successful device hash code vérification procedure, the time to access the network can be substantially reduced.

Furthermore, a fast switch or handover from one network to another of a UE is enabled by reusing the system Information that the UE has already stored. The UE calculâtes a device hash code for the system information. This device hash code is then transmitted to the network in an initial system connection phase, for example, as part of the random access procedure. The device hash code is compared with a corresponding network hash code. If the device hash code corresponds to the network hash code, this Indicates that the configured system information in the UE associated with the device hash code Is correct. The UE may then be allowed to immediately access the network. If the device hash code Is incorrect, i.e. that it does not correspond to the network hash code, the UE may e.g. be forced to listen for system Information broadcast by the network before accessing the network in order to update the configured Information. Alternatively the network may communîcate the correct system information to the UE In a dedicated way. The exchange of information between the UE and the network node In this embodiment comprises the sending by the UE of the device hash code to the network node and the sending by the network node of an indication in response to the device hash code, where the Indication indicates whether the configured system information in the UE needs to be updated. However, the exchange of information may in other embodiments be performed In other ways, e.g, as described in the subsection Embodiment D - Access Barrincf below.

One embodiment of the invention is hereinafter described with reference to Figure 2a which Is a flow chart illustrating a method according to embodiments of the invention. A UE has acqulred and configured system information S for one or more Systems or networks that the UE can connect to. This system information may comprise one or more of the following nonlimiting list of example parameters:

• Random access parameters, such as a set of random access pre-ambles to use, uplink time slot configurations for the physical random access channel, powercontrol and backoff parameters for the random access channel;

• System capabiîity information such as supported transmission modes, antenna configuration, Coordinated Multipoint (CoMP) capabilities, Supported LTE version information;

• Paging related information such as synchronization and démodulation reference sequences used for paging, or paging Indication channel configuration;

• Nelghboring cell related information such as multi-RAT neighbour Information, white-list, black list;

• Frequency band information such as carrier frequency, available uplink or downlink bands;

• Sub-frame number (SFN);

• Control channel mappings ;

• Data channel mappings;

• Power control settings;

· Cell re-selection parameters;

• System spécifie user Identification.

Many other system Information details can also be contained in the system information S, which is often structured In a system information table. It may be noted that the system Information table can contain information from different time periods and from multiple 15 Systems. The system information for a network a, referred to as S(a) typically changes rarely. In 210 the UE détermines a device hash code based on system information Sfa), e.g. by using system information S(a) as input data to a hash function. The device hash code is sent to the RBS that the UE wants to access. In 220 the RBS vérifiés the device hash code by e.g. comparing it with its own network hash code that has been determined by the RBS 20 based on system Information configured in the RBS. if the comparison indicates that the system information configured In the RBS corresponds to S(a) configured in the UE, the RBS will acknowledge that the device hash code Is correct in 230, and the UE may then conclude In 240 that the configured system Information in the UE S(a) can be used to directly access the RBS. On the other hand, if the comparison indicates that the system 25 information configured in the RBS does not correspond to the one configured In the UE, the

RBS will not acknowledge that the device hash code is correct in 230. The UE may then conclude that the configured system information in the UE S(a) Is incorrect for accessing the RBS and may préparé for an update of the configured system information based e.g. on System Information broadeasted by the RBS in 250. The system information Is thus not 30 always sent to the UE before the access to the network but only when it is determined that an update In the UE Is needed, as Illustrated In Figure 2a.

As described above, a non-acknowledgement of the device hash code from the RBS means that the UE 203 needs to update its configured system information. The RBS may inform the UE that the configured Information needs to be updated in different ways. In one embodiment, the UE Is explicitly notified that It needs to acquire new system Information with a message indicating that an update of the configured information is needed. In still another alternative embodiment, the Indication that the device hash code is incorrect and that the UE needs to update its configured information Is implicit when the UE does not receive any response to the transmitted device hash code. The RBS thus only acknowledges the réception of the device hash code when the device hash code Is verifîed to be correct.

In embodiments, some of the Information Sfa) of the system information table in a UE can be identified to belong to a particular system a. This system identification may be implemented in a number of ways. In one example embodiment, the carrier frequency and the system signature can be used for the system identification. Often the same configuration is used for the same carrier frequency and system signature. In some rare cases, for example, when two operators share the same carrier license and the user is moving between two base stations managed by the two operators the system Information can change even if this is not known by the UE.

In the following, different embodiments of the invention, denoted A-G, adapted to different use cases are described.

Embodiment A - Fast user identification

In this embodiment the system identification described above Is extended by also including some UE identification Information for a particular UE x. This UE identification information may be different for different Systems. If the UE identification information of a UE Is contained In the system information S(a,x) for which the device hash code Is determined, this makes it possible to détermine with some accuracy that the UE sending the device hash code is a UE that has access rights to the network.

Embodiment A is hereinafter described with reference to Figure 2b which is a signaling diagram illustrating the signaling between the RBS 201 and the UE 203, and between the

RBS 201 and the communication network 205 of the RBS 201. The RBS 201 may receive information from the network 205 related to a UE, UE(x), with rights to access the network

205 In S260. This UE identification information, UE ld info (x), may be transmitted to the RBS

201 from, for example, a compatible source RBS in case of handover, or from a CN node in case of e.g. Inter technology or operator handover. In some cases the vérification of the initial UE identification may be followed by additional vérification steps in S266 and S267, for example, using Information on the SIM-card of the UE.

In 261, a network hash code is determined by the RBS 201 based on configured system information S(a, x) In the RBS. S(a, x) also comprises the identifies of the UEs with access rights. Correspondingly, In 262, a device hash code is determined by the UE 203 based on system Information S(a, x) configured in the UE. The system Information S(a, x) configured In the UE comprises the identity x of the UE 203. In S263 the UE 203 transmits the device hash code to the RBS 201, which may then in 264 verify the device hash code by comparing It with the network hash code. Based on this comparison, the RBS 201 may indicate to the UE 203 in S268 whether the configured information in the UE 203 needs to be updated or not, e.g. by sending an acknowledgement meaning that the UE 203 is now accepted for direct access to the RBS. Altematively, the RBS may send a non-acknowledgement Indicating that the UE 203 needs to update Its system information, or that the UE is not identified as having access rights to the network 205.

In embodiments of the invention, separate hash codes may be determined for the system information S(a) and for the UE Identification information (x). Separate hash codes makes it possible for the UE to détermine whether it is the system information Sfa) that needs to be updated Indicated by a non-acknowledgement of the hash code associated with the System information, or whether the UE has no access right to the network indicated by a nonacknowledgement of the hash code associated with the UE identification information (x). This may be useful when the UE identity is represented by a relatively large number, which may be the case in a future network with a very large number of devices, or when the access rights consists of a relatively long security key that needs to be verified before it can be used.

Embodiment A may thus be used to make a first UE identification during the initial connection phase. The advantage is that UEs that are not allowed to connect can be quickly identified. This may be necessary In future Systems when a very lean system broadcast is used, making it more likely to hâve system configuration mismatches In the UEs.

Embodiment B - System configuration step

In this embodiment B, the vérification of the configured system information In the UE may take into account e.g. that the target RBS in a handover can support multiple configurations. For example, the UE can be configured for different operations for example for different

Quality of Service classes, ail supported by the target RBS. ln some cases the RBS is already configured for this configuration, in other cases the RBS needs to enable the operation. This is schematically depicted In the signaling diagram of Figure 2c. The RBS 201 may in 271 détermine the network hash codes for the system information Sfa, c) 5 according to several different configurations c. The network hash codes may e.g. be calculated using a hash function as described previously. However, only one of them - ci - is matching the configuration of the UE 203. The UE 203 may in 272 détermine the device hash code for S(a,c1) which is sent in S273 to the RBS 201. ln 274 the RBS 201 vérifiés the device hash code against the plurality of network hash codes to détermine the configuration 10 c1 used by the UE 203. ln 275, the RBS 201 adapts its configuration to configuration c1. ln

S276 the RBS 201 may then indicate to the UE 203 that the configured information In the UE 203 needs no update and can be used for direct access to the network 205.

Embodiment C - System sub-frame number fSFN) vérification

As mentioned in the background, one reason for a UE to read the system broadcast Is to 15 acquire the SFN of the system. The signaling of the SFN can be quite Infrequent which may hence delay a UE when accesslng the system.

ln embodiment C, the SFN is included in the system information Sfa). The SFN may be the only information in S(a). Such an embodiment may, for example, be used for a stationary UE such as an MTC-device that is sleeping for very long durations, as this also implies that the 20 SFN is potentially very large. The sleep cycle of the device then dictâtes together with the accuracy of the dock in the device the uncertainty of the SFN. If no synchronization should be done by the device a very high certainty that the SFN is correct is needed. However, with only a few bits of hash code or CRC determined based on the SFN and used according to embodiments of the invention, a very accurate check of the SFN can be done.

Embodiment D - Access barrinq

Embodiment D of the invention may be applied for an access barring use case. The system information in a cell may be updated based on the load in the cell. For high load situations the System information may be updated to block access for low priority users, e.g. Access Class Barring. A UE therefore needs to read the system Information before accessing the 30 system. To guarantee that the UE actually do read the system information, vérifications based on the device and network hash codes may be done. A UE accessing with an incorrect device hash code can thus be blocked by the system.

In one exemplary embodiment of the invention applied for one access barring use case, the device hash code is Included in the third message (Msg3) of the random access procedure sent from the UE to the RBS. The RBS may compare the received device hash code with its own network hash code to détermine whether the UE has read and stored the correct system information for the cell. The RBS may then indicate in the fourth message (Msg4),

i.e. in the contention resolution message of the random access procedure, whether the UE needs to update its configured system Information or not. A failed contention resolution may be an Indicator to the UE to read and update the system information. The RBS may also décidé to dynamically schedule additional broadcast signais when the device hash code vérification indicates that the UE needs to read and update the system information. In embodiments, the RBS may attempt to verify the device hash code using both a previously used and a current network hash code.

In another exemplary embodiment for access barring, the exchange of information between the UE and the RBS is initiated by the RBS instead of the UE. The exchange of information Is the basis for determining whether the configured information In the wireless device needs to be updated. The UE first sends a random access preamble In the first message (Msg1 ) of the random access procedure to the RBS according to prior art, to indicate that it wants to access the network. The RBS may then code the random access response in the second message (Msg2) using the network hash code. The UE may attempt to décodé the received random access response based on its device hash code. If the attempt to décodé fails, the UE may interpret this as an indication that the configured information in the UE needs to be updated, and may thus read and configure system information from the RBS. The initiated random access procedure is stopped and may be reinitiated by the UE after the update of the system information. If the configured information In the UE is correct and up to date, the UE will be able to décodé the random access response, and the random access procedure can proceed. The coding of the random access response may be performed by using a scrambling function that is initiated with the network hash code. The UE may then décodé using the same scrambling function and the device hash code. The decoding will thus only be successful if the device hash code corresponds to the network hash code. In embodiments, the UE may e.g. check the resuit from the decoding using an error detecting code such as a CRC.

In some embodiments, the UE may try different hypothesizes to détermine that the preamble was received but the system information has changed. The trial of different hypothèses may dépend on the coverage or the System to Interférence plus Noise (SINR) of the UE. For example, if the UE manages to detect that the network did transmit a response to the preamble but the UE could not successfully décodé and verify the content of the Msg2 transmission even though the received signal quality was suffîcient, then this may be an Indication that the decoding attempt failed because of an erroneous device hash code that did not correspond to the network hash code used to code Msg2. In this case the UE shall wait for a new broadcasted system information message before trying again to transmit a new random access preamble. If, on the other hand the SINR of the received Msg2 was poor, then the failed decoding could be due to that the network never transmitted Msg2 to this UE. In this case the UE shall re-transmit the random access preamble after some random back off time, without first waiting for a new system information transmission.

Embodiment E - Applying a hash code to a sub-set of the system Information

For many types of UEs not ail system information is relevant. For very low rate and low complexity usera, such as MTC devices, system parameters related to e.g. Coordinated Multipoint (CoMP) or Multiple Input - Multiple Output (ΜΙΜΟ) features may not be relevant since MTC devices cannot utilize such advanced features anyway. Hence the device hash code may for some UEs be calculated for a limited set of the system information. By verifying that the device hash code Is correct the network knows that parameters that are relevant when communicating with a particular UE are configured correctly.

Some system information parameters are very much related to mobility, such as IRAT neighboring lists. Hence, a plurality of hash codes may be calculated separately for different parts of the system Information. A plurality of device hash codes may in embodiments be communicated to the serving RBS. This makes it possible for the RBS to Indicate to the UE that only a smaller part of the system information associated with one of the plurality of device hash codes needs to be updated. This may e.g. be only information related to neighboring cells. This also Implies that only that part of the system Information may be transmitted to the UE for updating the configuration.

The embodiment E may be used to enable sélective retransmissions of the system information to UEs that are in bad coverage. For a UE it may be enough to Initially secure an updated sub-set of the system information, where the sub-set enables the UE to connect to the network. Therefore the device and the network hash code may be chosen to correspond to this sub-set of the system information. The device hash code of a UE in bad coverage that cannot fully décodé the broadcasted system information may be verified to be Incorrect by the RBS, and the RBS may therefore be able to retransmit this sub-set of the System information in a dedicated way to the UE. One example use-case may be a system capable of large beam-forming gains, where the UE can be in bad coverage for system broadcast although the UE has very good dedicated data speeds using e.g. massive ΜΙΜΟ.

Embodiment F - Received hash code unknown to the RBS

When calculating the network hash code for the system information in an RBS, the RBS may store both the network hash code and the corresponding system information in a mappïng table. If a device hash code is compared also to previously used network hash codes when it 5 does not match the current network hash code, the RBS may dérivé the system information that the UE currently has from the mapping table. Thereby, the RBS may send an update to the UE of the parts that need updating only. The advantage of such an embodiment Is that it minimizes the overhead related to the system information update.

When the RBS cannot match the device hash code received from the UE with any of the 10 previous and current network hash codes, this may be due to that some other network node configured the UE with system information from that node’s network. In this situation it may be bénéficiai to hâve a central node keeping track of the mapping table. Each time a network node configures a UE with system information associated with a network hash code, it informs a central node about both the network hash code and the associated system 15 information. Later, when the UE enters a new network node for which the device hash code

Is unknown, that network node may contact the central node to retrieve the associated system information. The network node may détermine based on the retrieved system information whether the configured information în the UE needs to be updated or not. In the central node that keeps track of different system information that has previously been used 20 in the network, there may be a need for some algorithm that periodically removes invalid or inactive mappings. For example, if a particular hash code is not reported as being used during a certain time window that mapping may be removed.

Embodiment G - Communïcatinq hash code as part of UE context in handover procedure

As the UE moves through the network the device hash code associated with the configured 25 system information in the UE may be communicated as part of the UE context that is handed over from a source to a target RBS. In case the device hash code is unknown to the target RBS, it may either ask the source RBS or a central node keeping track of the mapping between hash codes and system information.

Methods according to embodiments

Figure 3a Is a flowchart illustrating one embodiment of a method performed by a wireless device 500. The wireless device Is configured with information associated with either the wireless device, or one or more wireless communication networks to which the wireless device is connectable, or both. Examples of the configured information hâve been listed above. In embodiments, the wireless device 500 may be e.g. a UE, an MTC device, or any other klnd of terminal wirelessly communicating with a communication network. The method comprises:

- 310: Determining a device hash code based on the configured information in the wireless device.

- 320: Determining whether the configured Information in the wireless device needs to be updated based on the device hash code and an exchange of information with a network node 550 of a wireless communication network. The network node 550 may e.g. be an RBS of the communication network.

Figure 3b is a flowchart illustrating another embodiment of the method In the wireless device 500. When it is determined that the configured information In the wireless device needs to be updated, the method optionally comprises the below steps 330 and 340, in addition to the determining of a device hash code in 310 and the determining whether the configured information in the wireless device needs to be updated in 320 described above with reference to Figure 3a.

- 330: Receiving configuration information from the network node. The configuration information may be broadcasted by the network node, or may be received from the network node upon request from the wireless device.

- 340: Updating the configured information In the wireless device based on the received configuration Information.

When the wireless device has updated its configured Information, the wireless device may access or connect to the network node and may communicate with the network node. When It is determined that the configured information in the wireless device needs no update, the method may comprise the step of directly accessing or connecting to the network node without having to update any configured Information first. The advantage Is a faster access or connection to the network, as well as reduced overhead for distributing configuration information to the wireless device.

Figure 3c is a flowchart illustrating another embodiment of the method In the wireless device

500. The method comprises the determining of the device hash code based on the configured Information in the wireless device In 310 already described above. However, the determining whether the configured information in the wireless device needs to be updated,

In 320, may comprise:

- 321 : Transmitting the device hash code to the network node. ¹

- 322: Receiving an indication from the network node in response to the transmitted device hash code, the indication indicating whether the configured Information in the wireless device needs to be updated.

The indication received in 322 may be a message indicating that the configured information in the wireless device needs to be updated. Alternatively, the Indication that the configured information in the wireless device needs to be updated may be implicit by not receiving any message in response to the transmitted device hash code. The method may then further comprise receiving configuration Information from the network node in 330 and updating based on the received information in 340, as described with reference to Figure 3b. In another alternative embodiment, the received Indication is a message comprising configuration Information. The message indicates that the configured Information in the wireless device needs to be updated. The method may then further comprise updating the configured information in the wireless device based on the received configuration Information.

This is thus one example embodiment of how the exchange of information with the network node 550 may be performed to enable the determining of whether the configured information in the wireless device needs to be updated. Another example embodiment is described with reference to Figure 3d below.

Figure 3d is a flowchart illustrating another embodiment of the method in the wireless device 500. The embodiment has also been described In the subsection Embodiment D - Access barring” above. The method comprises the determining of the device hash code based on the configured information In the wireless device in 310, already described above. The determining whether the configured information in the wireless device needs to be updated, in 320, may comprise:

- 325: Transmitting a random access preamble to the network node.

- 326: Receiving a random access response from the network node coded using a network hash code associated with configured information in the network node.

- 327: Attempting to décodé the received random access response using the device hash code.

- 328: Determining that the configured information in the wireless device needs to be updated when the attempt to décodé fails.

Also this embodiment may be complemented with receiving configuration Information from the network node in 330 and updating based on the received information In 340, as described with reference to Figure 3b.

Figure 4a is a flowchart illustrating one embodiment of a method performed by the network node 550. The network node is configured with information associated with the wireless communication network. The embodiment corresponds to the method embodiment performed by the wireless device 500 described with reference to Figure 3a. The network node 550 may e.g. be an RBS of a wireless communication network, or a core network or System management node. The method comprises:

- 410: Determining a network hash code based on the configured information In the network node.

- 420: Directing information which is based on the network hash code to a wireless device 500, which may be a UE. The information enables the wireless device to détermine whether configured Information In the wireless device needs to be updated.

Figure 4b is a flowchart illustrating another embodiment of the method In the network node 550. This embodiment corresponds to the embodiment for the method in wireless device described with reference to Figure 3c above. In addition to the determining of the network hash code in 410 described above with reference to Figure 4a, the method optionally comprises:

- 415: Receiving the device hash code from the wireless device.

- 416: Comparing the device hash code with the network hash code.

Furthermore, directing the information in 420 may comprise:

- 421: Indicating to the wireless device whether the configured information in the wireless device needs to be updated based on the comparison. The indicating may comprise one of the following: transmitting a message to the wireless device indicating that an update of the configured Information In the wireless device is needed; transmitting configuration information to the wireless device indicating that an update based on the configuration Information Is needed; and Implicitly indicating that an update of the configured Information in the wireless device is needed by not transmitting a message In response to the received device hash code.

In one embodiment corresponding to embodiment A described previously, the device hash code may be associated also with an identity of the wireless device. The method may then further comprise determining the identity of the wireless device using the device hash code, and deciding whether the wireless device should hâve access to the system based on the determined identity. This decision may e.g. be based on subscription information for the wireless device that the network node has access to.

As described for embodiment B above, the determining of the network hash code In 410 may comprise determining two network hash codes based on two alternative configurations associated with the wireless communication network. The comparing in 416 may thus comprise matching the device hash code against the two network hash codes. When a match is found, the method may further comprise selecting the alternative configuration corresponding to the matching one of the two network hash codes. Directing the Information in 420 may then comprise indicating to the wireless device that the configured Information In the wireless device needs no update.

Figure 4c ls a flowchart illustrating another embodiment of the method in the network node 550. This embodiment corresponds to the embodiment for the method in wireless device described with reference to Figure 3d above. The method optionally comprises, in addition to the determining of the network hash code in 410 described above with reference to Figure 4a:

- 417: Receiving a random access preamble from the wireless device.

- 418: Coding a random access response using the network hash code.

Directing the information In 420 may comprise:

- 422: Transmitting the coded random access response to the wireless device, such that an attempt to décodé the random access response by the wireless device based on the device hash code Indicates to the wireless device whether the configured information in the wireless device needs to be updated.

Apparatus according to embodiments

An embodiment of a wireless device 500 and a network node 550 is schematically illustrated In the block diagram in Figure 5a. The wireless device may e.g. be a mobile terminal or an MTC device, and the network node may be a radio network node, a core network node, or a system management node of a wireless communication network. The wireless device 500 is configured with information associated with either the wireless device, or one or more wireless communication networks to which the wireless device is connectable, or both. Examples of the configured information hâve been listed above. The wireless device is further configured to détermine a device hash code based on the configured information in the wireless device, and to détermine whether the configured information in the wireless device needs to be updated based on the device hash code and an exchange of information with the network node 550 of the wireless communication network.

In one embodiment, the wireless device may be configured to détermine whether the configured information in the wireless device needs to be updated by transmitting the device hash code to the network node, and by receiving an indication from the network node in response to the transmitted device hash code. The indication indicates whether the configured information in the wireless device needs to be updated.

The indication may be a message indicating that the configured information in the wireless device needs to be updated. Alternatively, the indication that the configured Information in the wireless device needs to be updated Is implicit by not receiving any message in response to the transmitted device hash code. The wireless device may be further configured to receive configuration Information from the network node, and update the configured information in the wireless device based on the received configuration information. The configuration information may be broadcasted by the network node, or may be received from the network node upon request from the wireless device.

The received indication may alternatively be a message comprising configuration information. The message then Indicates that the configured information In the wireless device needs to be updated. The wireless device may be further configured to update the configured information in the wireless device based on the received configuration Information.

In another embodiment (see embodiment D above), the wireless device 500 may be configured to détermine whether the configured information in the wireless device needs to be updated by transmitting a random access preamble to the network node, receiving a random access response from the network node coded using a network hash code associated with configured information in the network node, and attempting to décodé the received random access response using the device hash code. The wireless device may In this embodiment be further configured to détermine that the configured information in the wireless device needs to be updated when the attempt to décodé fails. The wireless device may be further configured to receive configuration information from the network node, and update the configured Information In the wireless device based on the received configuration information. The configuration information may be broadcasted by the network node, or may be received from the network node upon request from the wireless device.

The network node 550 in the block diagram In Figure 5a is configured for operation in a wireless communication network. The network node Is also configured with information associated with the wireless communication network, and to détermine a network hash code based on the configured information in the network node. The network node is further configured to direct information which Is based on the network hash code to the wireless device 500. The Information enables the wireless device to détermine whether configured information in the wireless device needs to be updated.

In one embodiment, the network node 550 may be further configured to receive the device hash code from the wireless device, and compare the device hash code with the network hash code. The network node may be further configured to direct the information to the wireless device by indicating to the wireless device whether the configured information in the wireless device needs to be updated based on the comparison. The network node 550 may be further configured to indicate whether the configured Information in the wireless device needs to be updated by one of the following: transmitting a message to the wireless device indicating that an update of the configured Information in the wireless device is needed: transmitting configuration information to the wireless device Indicating that an update based on the configuration information is needed; and impîîcitîy indicating that an update of the configured Information In the wireless device Is needed by not transmitting a message in response to the received device hash code.

The device hash code received from the wireless device may be associated also with an identity of the wireless device. The network node 550 may be further configured to détermine the Identity of the wireless device using the device hash code, and décidé whether the wireless device should hâve access to the system based on the determined identity.

The network node 550 may be configured to détermine the network hash code by determining two network hash codes based on two alternative configurations associated with the wireless communication network. The network node may be further configured to compare hash codes by matching the device hash code against the two network hash codes. When a match Is found, the network node may be configured to select one of the two alternative configurations corresponding to the matching one of the two network hash codes, and direct Information by indicating to the wireless device that the configured Information in the wireless device needs no update.

In another embodiment, the network node 550 may be further configured to receive a random access preamble from the wireless device, and code a random access response using the network hash code. The network node may be configured to direct information by transmitting the coded random access response to the wireless device, such that an attempt to décodé the random access response by the wireless device based on the device hash code indicates to the wireless device whether the configured information in the wireless device needs to be updated.

In embodiments of the invention, the wireless device 500 may comprise a processing circuit 501 and a memory 502 as illustrated in Figure 5a. The wireless device may also comprise a transceiver circuit 503 configured to communicate wirelessly with the network node 550 and connected to the processing circuit 501. The transceiver circuit 503 may be connected to one or more antennas via one or more antenna ports. The memory 502 contains instructions exécutable by said processing circuit 501 whereby said wireless device 500 is operative to détermine a device hash code based on the configured Information In the wireless device, and détermine whether the configured information in the wireless device needs to be updated based on the device hash code and an exchange of information with the network node 550 of the wireless communication network.

In one embodiment, the memory 502 may contain further Instructions exécutable by the processing circuit 501, whereby the wireless device 500 may be operative to détermine whether the configured information in the wireless device needs to be updated by transmitting the device hash code to the network node, and by receiving an indication from the network node in response to the transmitted device hash code. The indication indicates whether the configured Information in the wireless device needs to be updated.

The indication may be a message Indicating that the configured information In the wireless device needs to be updated. Altematively, the Indication that the configured information In the wireless device needs to be updated is implicit by not receiving any message In response to the transmitted device hash code. The wireless device 500 may be operative to receive configuration Information from the network node, and to update the configured information in the wireless device based on the received configuration information. The configuration information may be broadcasted by the network node, or may be received from the network node upon request from the wireless device.

The received indication may altematively be a message comprising configuration • information. The message then indicates that the configured information in the wireless device needs to be updated. The wireless device may be operative to update the configured information in the wireless device based on the received configuration information.

In another embodiment (see embodiment D above), the memory 502 may contain further instructions exécutable by the processing circuit 501, whereby the wireless device 500 may be operative to détermine whether the configured Information In the wireless device needs to be updated by transmitting a random access preamble to the network node, by receiving a random access response from the network node coded using a network hash code associated with configured Information in the network node, and by attempting to décodé the 10 received random access response using the device hash code. The wireless device may in this embodiment further be operative to détermine that the configured information In the wireless device needs to be updated when the attempt to décodé fails. The wireless device may be operative to receive configuration Information from the network node, and to update the configured information in the wireless device based on the received configuration 15 information. The configuration information may be broadcasted by the network node, or may be received from the network node upon request from the wireless device.

Furthermore, the network node 550 may comprise a processing circuit 551 and a memory 552 as illustrated in Figure 5a. The network node may also comprise a communication interface 553 connected to the processing circuit 551 and configured to communicate with 20 the wireless device 500 either directly over the air, or via another network node. The communication interface 553 may thus be connected to one or more antennas via one or more antenna ports in some embodiment. The memory 552 contains instructions exécutable by said processing circuit 551 whereby said network node 550 Is operative to détermine a network hash code based on the configured information in the network node, and direct 25 information which is based on the network hash code to a wireless device 500. The Information enables the wireless device to détermine whether configured Information in the wireless device needs to be updated.

In one embodiment, the memory 552 may contain further instructions exécutable by the processing circuit 551, whereby the network node 550 is operative to receive the device 30 hash code from the wireless device, and to compare the device hash code with the network hash code. The network node may be operative to direct the Information to the wireless device by indicating to the wireless device whether the configured information in the wireless device needs to be updated based on the comparison. The network node 550 may be operative to indicate whether the configured information in the wireless device needs to be 35 updated by one of the following: transmitting a message to the wireless device indicating that an update of the configured Information in the wireless device is needed; transmitting configuration information to the wireless device Indicating that an update based on the configuration information is needed; and ïmplicitly Indicating that an update of the configured information In the wireless device is needed by not transmitting a message In response to 5 the received device hash code.

The device hash code received from the wireless device may be associated also with an identity of the wireless device. The memory 552 may contain further Instructions exécutable by the processing circuit 551, whereby the network node 550 is operative to détermine the Identity of the wireless device using the device hash code, and to décidé whether the 10 wireless device should hâve access to the system based on the determined identity.

The memory 552 may contain further Instructions exécutable by the processing circuit 551, whereby the network node 550 Is operative to détermine the network hash code by determining two network hash codes based on two alternative configurations associated with the wireless communication network. The network node may be operative to compare hash 15 codes by matchlng the device hash code against the two network hash codes. When a match is found, the network node may be operative to select one of the two alternative configurations corresponding to the matching one of the two network hash codes, and to direct Information by indicating to the wireless device that the configured information In the wireless device needs no update.

In another embodiment, the memory 552 may contain further instructions exécutable by the processing circuit 551, whereby the network node 550 Is operative to receive a random access preamble from the wireless device, and to code a random access response using the network hash code. The network node may be operative to direct information by transmitting the coded random access response to the wireless device, such that an attempt to décodé 25 the random access response by the wireless device based on the device hash code

Indicates to the wireless device whether the configured information in the wireless device needs to be updated.

In an alternative way to describe the embodiment in Figure 5a, illustrated in Figure 5b, the wireless device 500 may comprise a first means for determining 513 adapted to détermine a 30 device hash code based on the configured Information in the wireless device. The wireless device may also comprise a second means for determining 514 adapted to détermine whether the configured Information in the wireless device needs to be updated based on the device hash code and an exchange of Information with a network node 550 of a wireless communication network.

In one embodiment, the second means for determining 514 whether the configured information In the wireless device needs to be updated comprises means for transmitting the device hash code to the network node, and means for receiving an indication from the network node In response to the transmitted device hash code. The Indication indicates whether the configured information in the wireless device needs to be updated.

The indication may be a message indicating that the configured information in the wireless device needs to be updated. Altematively, the indication that the configured information in the wireless device needs to be updated Is Implicit by not receiving any message in response to the transmitted device hash code. The wireless device may be further comprise means for receiving configuration information from the network node, and means for updating the configured information in the wireless device based on the received configuration information. The configuration information may be broadcasted by the network node, or may be received from the network node upon request from the wireless device.

The received Indication may altematively be a message comprising configuration information. The message then indicates that the configured information In the wireless device needs to be updated. The wireless device may further comprise means for updating the configured information in the wireless device based on the received configuration information.

In another embodiment (see embodiment D above), the second means for determining 514 whether the configured information In the wireless device needs to be updated comprises means for transmitting a random access preamble to the network node, means for receiving a random access response from the network node coded using a network hash code associated with configured information In the network node, and means for attempting to décodé the received random access response using the device hash code. The wireless device may in this embodiment further comprise means for determining that the configured information in the wireless device needs to be updated when the attempt to décodé fails. The wireless device may further comprise means for receiving configuration information from the network node, and means for updating the configured information In the wireless device based on the received configuration information. The configuration information may be broadcasted by the network node, or may be received from the network node upon request from the wireless device.

Furthermore, the network node 550 comprises a means for determining 561 adapted to détermine a network hash code based on the configured information In the network node, and a means for directing 562 adapted to direct information which is based on the network hash code to the wireless device 500. The information enables the wireless device to détermine whether configured information in the wireless device needs to be updated.

In one embodiment, the network node 550 may further comprise means for receiving the device hash code from the wireless device, and comparing the device hash code with the network hash code. The means for directing 562 the information to the wireless device may comprise means for indicating to the wireless device whether the configured information in the wireless device needs to be updated based on the comparison. The network node 550 may further comprise means for indicating whether the configured information in the wireless device needs to be updated comprising one of the following: means for transmitting a message to the wireless device indicating that an update of the configured information in the wireless device is needed; means for transmitting configuration information to the wireless device indicating that an update based on the configuration information is needed; and means for Implicltly indicating that an update of the configured information in the wireless device is needed by not transmitting a message in response to the received device hash code.

The device hash code received from the wireless device may be associated also with an identity of the wireless device. The network node 550 may further comprise means for determining the identity of the wireless device using the device hash code, and means for deciding whether the wireless device should hâve access to the system based on the determined identity.

The means for determining 561 the network hash code may comprise means for determining two network hash codes based on two alternative configurations associated with the wireless communication network. The network node may further comprise means for comparing hash codes by matching the device hash code against the two network hash codes. When a match is found, the network node may comprise means for selecting one of the two alternative configurations corresponding to the matching one of the two network hash codes, and the means for directing 562 Information may comprise means for indicating to the wireless device that the configured Information (n the wireless device needs no update.

In another embodiment, the network node 550 may further comprise means for receiving a random access preamble from the wireless device, and means for coding a random access response using the network hash code. The means for directing 562 Information may comprise means for transmitting the coded random access response to the wireless device, such that an attempt to décodé the random access response by the wireless device based on the device hash code indicates to the wireless device whether the configured Information

In the wireless device needs to be updated.

The means described above are functional units which may be implemented in hardware, software, firmware or any combination thereof. In one embodiment, the means are implemented as a computer program running on a processor.

In still another alternative way to describe the embodiment in Figure 5a, the wireless device 500 may comprise a Central Processing Unit (CPU) which may be a single unit or a plurality of units. Furthermore, the wireless device may comprise at least one computer program product (CPP) In the form of a non-volatile memory, e.g. an EEPROM (Electrically Erasable Programmable Read-Only Memory), a flash memory or a disk drive. The CPP may comprise a computer program, which comprises code means which when run on the CPU of the wireless device causes the wireless device to perform the methods described earlier in conjunction with Figures 3a-d. In other words, when said code means are run on the CPU, they correspond to the processing circuit 501 in Figure 5a. Furthermore, the network node 550 may comprise a Central Processing Unit (CPU) which may be a single unit or a plurality of units. Furthermore, the network node 550 may comprise at least one computer program product (CPP) in the form of a non-volatile memory, e.g. an EEPROM (Electrically Erasable Programmable Read-Only Memory), a flash memory or a disk drive. The CPP may comprise a computer program, which comprises code means which when run on the CPU of the network node 550 causes the network node to perform the methods described earlier in conjunction with Figures 4a-c. In other words, when said code means are run on the CPU, they correspond to the processing circuit 551 in Figure 5a.

The above mentioned and described embodiments are only given as examples and should not be limiting. Other solutions, uses, objectives, and functions within the scope of the accompanying patent claims may be possible.

Claims (9)

1. A method performed by a wireless device , wherein the wireless device is configured with information associated with at least one of the wireless device and one or more wireless communication networks to which the wireless device is connectable, the method comprising:

- determining a device hash code based on the configured information In the wireless device, and

- determining whether the configured information in the wireless device needs to be updated based on the device hash code and an exchange of Information with a network node of a wireless communication network, wherein determining whether the configured information in the wireless device needs to be updated further comprises:

- transmitting a random access preamble to the network node,

- receiving a random access response from the network node coded using a network hash code associated with configured information In the network node,

- attempting to décodé the received random access response using the device hash code, the method comprising when the attempt to décodé faits:

- determining that the configured information in the wireless device needs to be updated.

2. The method according to claim 1, the method further comprising:

- receiving configuration Information from the network node, and

- updating the configured information in the wireless device based on the received configuration information.

3. A method performed by a network node of a wireless communication network, wherein the network node is configured with information associated with the wireless communication network, the method comprising:

- determining a network hash code based on the configured Information in the network node.

- receiving a random access preamble from the wireless device, and

- coding a random access response using the network hash code,

- transmitting the coded random access response to the wireless device, such that an attempt to décodé the random access response by the wireless device based on the device hash code indicates to the wireless device whether the configured Information In the wireless device needs to be updated.

4. A wireless device configured with information associated with at least one of the wireless device and one or more wireless communication networks to which the wireless device Is connectable, the wireless device being further configured to:

- détermine a device hash code based on the configured information in the wireless device, and

- détermine whether the configured information In the wireless device needs to be updated based on the device hash code and an exchange of information with a network node of a wireless communication network, by being configured to:

- transmit a random access preamble to the network node, and

- receive a random access response from the network node coded using a network hash code associated with configured information in the network node,

- attempt to décodé the received random access response using the device hash code, the wireless device being further configured to:

- détermine that the configured information in the wireless device needs to be updated when the attempt to décodé fails.

5. The wireless device according to claim 4, further configured to:

- receive configuration information from the network node, and

- update the configured information in the wireless device based on the received configuration information.

6. A network node for operation ln a wireless communication network, wherein the network node is configured with information associated with the wireless communication network, the network node being further configured to:

- détermine a network hash code based on the configured information in the network node, and

- receive a random access preamble from the wireless device, and

- code a random access response using the network hash code, and the network node being configured to direct information which is based on the network hash code to a wireless device by:

- transmitting the coded random access response to the wireless device, such that an attempt to décodé the random access response by the wireless device based on the device hash code Indicates to the wireless device whether the configured information ln the wireless device needs to be updated.

7. A computer program comprising computer readable code which when run on a wireless device causes the wireless device to perform a method as claimed in any of claims 1-2.

8. A computer program comprising computer readable code which when run on a network node causes the network node to perform a method as claimed ln claim

3.

9. A computer program product comprising a computer readable medium and a computer program according to claim 7 or 8, wherein the computer program is stored on the computer readable medium.