WO2021156399A1

WO2021156399A1 - Guti reallocation for mt-edt in 5gc and other systems

Info

Publication number: WO2021156399A1
Application number: PCT/EP2021/052727
Authority: WO
Inventors: Srinivasan Selvaganapathy; Philippe Godin; Suresh Nair
Original assignee: Nokia Technologies Oy
Priority date: 2020-02-06
Filing date: 2021-02-05
Publication date: 2021-08-12

Abstract

Methods, apparatuses, and computer program products described herein may provide identifiers for user equipment such as Global Unique Temporary Identifier (GUTIs) in the networks. A method comprises, in a network node in a wireless network, communicating with a user equipment in the wireless network to set a plurality of identifiers to be used for paging after early data transfer procedures to transfer data to the user equipment using random access procedures, the identifiers identifying at least the user equipment for the early data transfer procedures; And the method further comprises performing early data transfer procedures to transfer data from the network node to the user equipment using corresponding multiple ones of the identifiers.

Description

GUTI Reallocation for MT-EDT in 5GC and Other Systems

TECHNICAL FIELD

This invention relates generally to wireless networks and, more specifically, relates to identifiers for user equipment such as Global Unique Temporary Identifier (GUTIs) in the networks.

BACKGROUND

Abbreviations that may be found in the specification and/or the drawing figures are defined below, at the end of the detailed description section.

In fifth generation (5G) systems, at the time of registration, the user equipment (UE) is assigned with a global unique temporary identifier (GUTI), which comprises a globally unique AMF identifier (GUAMI), which uniquely identifies an access and mobility management function (AMF), and a 5G system architecture evolution (SAE)-temporary mobile subscriber identity (S-TMSI) value, which uniquely identifies the UE at least to the AMF. This identifier is used in further non-access stratum (NAS) signaling towards the UE. When the AMF triggers a paging message toward the UE, this identifier is used in the paging message to identify the UE.

To enhance the security associated with GUTI assignment, e.g., to avoid tracking of the UE based on the GUTI in the network, the AMF uses a GUTI reallocation procedure to frequently re-assign the GUTI towards the UE. The AMF may start the GUTI reallocation procedure as part of any ongoing NAS signaling procedure. As the 5G-S-TMSI is sent as plain text (not ciphered or otherwise encrypted) in the paging messages, it is necessary to re-assign the GUTI as part of a serving request initiated from the UE in response to the paging message. This procedure is mandatory in 5G for every NAS signaling procedure followed by paging towards UE.

For small data transmission from Cellular Internet of things (CIoT) devices in idle mode, early data transfer (EDT) procedures are introduced in Rel-15 (Release 15), where the small data transmission happens during the random-access procedure itself without UE transition from an idle mode to a connected mode. This procedure, where the UE sends small data without setting up a radio resource control (RRC) connection during a random-access channel (RACH) procedure, is known as the MO-EDT (mobile-originated-early data transmission) procedure. That is, a RACH procedure is used to transfer data instead of the UE completing the RACH procedure, creating an RRC connection, then transferring data.

In Rel-16, 3GPP defined feature support for CIoT devices in 3GPP TS 23.501 (see, e.g., 3GPP TS 23.501 V16.3.0 (2019-12)) specifically clauses 5.31 and 5.31.14.3. Exchange of ‘Small data’ is one of the sub-features specified in this clause. Small data transmission from the network towards an idle mode UE is supported using MT-EDT (mobile-terminated-early data transmission procedure). In this case, the network sends the paging message to initiate the MT- EDT procedure by sending the paging message with an additional indication that the paging is for MT-EDT. As part of RACH procedure initiated in response to the paging message, the network sends the small amount of data in the Msg4 associated with the random-access procedure, and the UE enters into idle mode after receiving this packet. In this case, the UE does not set up an RRC connection for receiving the small data. This procedure is typically applicable when the network wants to send a single small data transmission whose size can fit into single radio transmission.

When the MT-EDT procedure is initiated by the AMF towards a 5G CIoT device connected to the network, the transmission cannot be completed without the device entering into an RRC connected mode, as the GUTI reallocation is mandatory for any procedure followed by the paging procedure. Thus, the benefits of MT-EDT of avoiding RRC connection setup is not possible when, e.g., a CIoT device connects to AMF (e.g., via a 5G core network).

BRIEF DESCRIPTION OF THE DRAWINGS In the attached Drawing Figures:

FIG. 1 is a block diagram of one possible and non-limiting exemplary system in which the exemplary embodiments may be practiced;

FIG. 2 is a logic flow diagram for GUTI reallocation for MT-EDT in 5GC and other systems, and describes GUTI list assignment and rotation of identifiers for MT-EDT in an exemplary embodiment; FIG. 2A is another logic flow diagram for GUTI reallocation for MT-EDT in 5GC and other systems, and describes derivation of a next GUTI index using NAS security keys and a formula for a CP solution for an exemplary embodiment;

FIG. 2B is another logic flow diagram for GUTI reallocation for MT-EDT in 5GC and other systems, and describes GUTI re-allocation for a UP MT-EDT solution for an exemplary embodiment; and

FIG. 3 is a signaling diagram of a procedure for assignment of GUTI list for MT-EDT paging and implicit switching of GUTI after MT-EDT procedure, in an exemplary embodiment, and illustrates certain operations from FIG. 2B.

DETAILED DESCRIPTION OF THE DRAWINGS

The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described in this Detailed Description are exemplary embodiments provided to enable persons skilled in the art to make or use the invention and not to limit the scope of the invention which is defined by the claims.

The exemplary embodiments herein describe techniques for GUTI Reallocation for MT-EDT in 5GC and other systems. Additional description of these techniques is presented after a system into which the exemplary embodiments may be used is described.

Turning to FIG. 1, this figure shows a block diagram of one possible and non-limiting exemplary system in which the exemplary embodiments may be practiced. A user equipment (UE) 110, radio access network (RAN) node 170, and network element(s) 190 are illustrated. In FIG. 1, a user equipment (UE) 110 is in wireless communication with a wireless network 100. A UE is a wireless, typically mobile device that can access a wireless network. The UE 110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected through one or more buses 127. Each of the one or more transceivers 130 includes a receiver, Rx, 132 and a transmitter, Tx, 133. The one or more buses 127 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, and the like. The one or more transceivers 130 are connected to one or more antennas 128. The one or more memories 125 include computer program code 123. The UE 110 includes a control module 140, comprising one of or both parts 140-1 and/or 140-2, which may be implemented in a number of ways. The control module 140 may be implemented in hardware as control module 140-1, such as being implemented as part of the one or more processors 120. The control module 140-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example, the control module 140 may be implemented as control module 140-2, which is implemented as computer program code 123 and is executed by the one or more processors 120. For instance, the one or more memories 125 and the computer program code 123 may be configured to, with the one or more processors 120, cause the user equipment 110 to perform one or more of the operations as described herein. The UE 110 communicates with RAN node 170 via a wireless link 111.

The RAN node 170 is a base station that provides access by wireless devices such as the UE 110 to the wireless network 100. The RAN node 170 may be, for instance, a base station for 5G, also called New Radio (NR). In 5G, the RAN node 170 may be a NG-RAN node, which is defined as either a gNB or an ng-eNB. A gNB is a node providing NR user plane and control plane protocol terminations towards the UE, and connected via the NG interface to a 5GC (e.g., the network element(s) 190). The ng-eNB is a node providing E-UTRA user plane and control plane protocol terminations towards the UE, and connected via the NG interface to the 5GC. In the text below, the RAN node 170 is considered to be, for ease of reference, a gNB, but this is not limiting.

The NG-RAN node may include multiple gNBs, which may also include a central unit (CU) (gNB-CU) 196 and distributed unit(s) (DUs) (gNB-DUs), of which DU 195 is shown. Note that the DU may include or be coupled to and control a radio unit (RU). The gNB-CU is a logical node hosting RRC, SDAP and PDCP protocols of the gNB or RRC and PDCP protocols of the en-gNB that controls the operation of one or more gNB-DUs. The gNB-CU terminates the FI interface connected with the gNB-DU. The FI interface is illustrated as reference 198, although reference 198 also illustrates a link between remote elements of the RAN node 170 and centralized elements of the RAN node 170, such as between the gNB-CU 196 and the gNB- DU 195. The gNB-DU is a logical node hosting RLC, MAC and PHY layers of the gNB or en- gNB, and its operation is partly controlled by gNB-CU. One gNB-CU supports one or multiple cells. One cell is supported by only one gNB-DU. The gNB-DU terminates the FI interface 198 connected with the gNB-CU. Note that the DU 195 is considered to include the transceiver 160, e.g., as part of an RU, but some examples of this may have the transceiver 160 as part of a separate RU, e.g., under control of and connected to the DU 195. The RAN node 170 may also be an eNB (evolved NodeB) base station, for LTE (long term evolution), or any other suitable base station.

The RAN node 170 includes one or more processors 152, one or more memories 155, one or more network interfaces (N/W I/F(s)) 161, and one or more transceivers 160 interconnected through one or more buses 157. Each of the one or more transceivers 160 includes a receiver, Rx, 162 and a transmitter, Tx, 163. The one or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153. The CU 196 may include the processor(s) 152, memories 155, and network interfaces 161. Note that the DU 195 may also contain its own memory/memories and processor(s), and/or other hardware, but these are not shown.

The RAN node 170 includes a control module 150, comprising one of or both parts 150-1 and/or 150-2, which may be implemented in a number of ways. The control module 150 may be implemented in hardware as control module 150-1, such as being implemented as part of the one or more processors 152. The control module 150-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example, the control module 150 may be implemented as control module 150-2, which is implemented as computer program code 153 and is executed by the one or more processors 152. For instance, the one or more memories 155 and the computer program code 153 are configured to, with the one or more processors 152, cause the RAN node 170 to perform one or more of the operations as described herein. Note that the functionality of the control module 150 may be distributed, such as being distributed between the DU 195 and the CU 196, or be implemented solely in the DU 195.

The one or more network interfaces 161 communicate over a network such as via the links 176 and 131. Two or more RAN nodes 170 communicate using, e.g., link 176. The link 176 may be wired or wireless or both and may implement, e.g., an Xn interface for 5G, an X2 interface for LTE, or other suitable interface for other standards. The one or more buses 157 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, wireless channels, and the like. For example, the one or more transceivers 160 may be implemented as a remote radio head (RRH) 195 for LTE or a distributed unit (DU) 195 for gNB implementation for 5G, with the other elements of the RAN node 170 possibly being physically in a different location from the RRH/DU, and the one or more buses 157 could be implemented in part as, e.g., fiber optic cable or other suitable network connection to connect the other elements (e.g., a central unit (CU), gNB-CU) of the RAN node 170 to the RRH/DU 195. Reference 198 also indicates those suitable network link(s).

The wireless network 100 may include a network element or elements 190 that may include core network functionality, and which provides connectivity via a link or links 181 with a further network, such as a telephone network and/or a data communications network (e.g., the Internet). Such core network functionality for 5G may include access and mobility management function(s) (AMF(s)) and/or user plane functions (UPF(s)) and/or session management function(s) (SMF(s)). Such core network functionality for LTE may include MME (Mobility Management Entity )/SGW (Serving Gateway) functionality. These are merely exemplary functions that may be supported by the network element(s) 190, and note that both 5G and LTE functions might be supported. In the examples herein (one of) the network element (elements) 190 is considered to be an AMF, which will be referred to as AMF 190 in other figures, described below.

In FIG. 1, the RAN node 170 is coupled via a link 131 to a network element 190. The link 131 may be implemented as, e.g., an NG interface for 5G, or an SI interface for LTE, or other suitable interface for other standards. The network element 190 includes one or more processors 175, one or more memories 171, and one or more network interfaces (N/W I/F(s)) 180, interconnected through one or more buses 185. The one or more memories 171 include computer program code 173, which includes a control module (CM) 151-2. The one or more memories 171 and the computer program code 173 are configured to, with the one or more processors 175 and based on execution of the CM 151-2, cause the network element 190 to perform one or more operations as described herein. The control module 151-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array, as shown by example in the processor(s) 175. Thus, the control module 151 may be implemented via hardware, software executed by hardware, or some combination of these.

The wireless network 100 may implement network virtualization, which is the process of combining hardware and software network resources and network functionality into a single, software-based administrative entity, a virtual network. Network virtualization involves platform virtualization, often combined with resource virtualization. Network virtualization is categorized as either external, combining many networks, or parts of networks, into a virtual unit, or internal, providing network-like functionality to software containers on a single system. Note that the virtualized entities that result from the network virtualization are still implemented, at some level, using hardware such as processors 152 or 175 and memories 155 and 171, and also such virtualized entities create technical effects.

The computer readable memories 125, 155, and 171 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The computer readable memories 125, 155, and 171 may be means for performing storage functions. The processors 120, 152, and 175 may be of any type suitable to the local technical environment, and may include one or more of general-purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on a multi core processor architecture, as non-limiting examples. The processors 120, 152, and 175 may be means for performing functions, such as controlling the UE 110, RAN node 170, and other functions as described herein.

In general, the various embodiments of the user equipment 110 can include, but are not limited to, cellular telephones such as smart phones, tablets, personal digital assistants (PDAs) having wireless communication capabilities, portable computers having wireless communication capabilities, vehicles with a modem device for wireless V2X (vehicle-to-everything) communication, image capture devices such as digital cameras having wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback appliances having wireless communication capabilities, Internet appliances (including Internet of Things, IoT, devices) permitting wireless Internet access and possibly browsing, IoT devices with sensors and/or actuators for automation applications with wireless communication tablets with wireless communication capabilities, as well as portable units or terminals that incorporate combinations of such functions.

Having thus introduced one suitable but non-limiting technical context for the practice of the exemplary embodiments of this invention, the exemplary embodiments will now be described with greater specificity.

As described above, there are certain scenarios wherein the current EDT procedures are not ideal. For instance, the benefits of MT-EDT of avoiding RRC connection setup is not possible when, e.g., a CIoT device connects to AMF (e.g., via a 5G core network). This is true because the transmission cannot be completed without the device entering into an RRC connected mode, as the GUTI reallocation is mandatory for any procedure followed by the paging procedure.

One of the techniques that has been proposed to resolve this is to assign the GUTI via one-way procedure without waiting for acknowledgement from the UE. This can lead, however, to inconsistency of the GUTI between UE and the network in case the procedure fails. The AMF which assigns the GUTI would have to blindly believe that the procedure succeeded without a positive acknowledgement from the receiving UE.

By contrast, the exemplary embodiments herein propose GUTI-hopping procedures which will address the above problems for MT-EDT and corresponding data transfers. The following exemplary signaling methods support GUTI reallocation for every MT-EDT without a need for the UE entering into connected mode. Note that an early data procedure may be described as follows. Data is transmitted during a RACH access procedure itself without UE establishing an RRC connection. For the exemplary embodiments herein, if the network wants to send only one small packet of downlink data, the network informs the same in the paging message to UE, so that UE and NW exchange this downlink data as part of RACH access procedure itself without establishing RRC connection. FIG. 2 is a logic flow diagram for GUTI reallocation for MT-EDT in 5GC and other systems. This figure further illustrates the operation of an exemplary method or methods, a result of execution of computer program instructions embodied on a computer readable memory, functions performed by logic implemented in hardware, and/or interconnected means for performing functions in accordance with exemplary embodiments. For instance, the control module 140 for the UE 110 and control module 151 for the AMF 190 may include operations multiples ones of the blocks in FIG. 2, where each included block is an interconnected means for performing the function in the block. The operations in blocks in FIG. 2 are assumed to be performed by one or both of the UE 110, e.g., under control of the control module 140 at least in part or by the AMF 190, e.g., under control of the control module 151 at least in part.

The method in FIG. 2 involves GUTI list assignment and rotation of identifiers for MT-EDT. Other methods, described below, use different techniques.

In block 210, the AMF 190 sends a list 205 of GUTI values with a UE 110 capable of MT- EDT procedure as part of a registration procedure. This list 205 is a new list of identifiers assigned to UE for MT-EDT purpose in addition to a “normal” GUTI. As indicated by reference 213, each GUTI corresponds to an index. That is GUIT1 corresponds to indexl, GUTI2 corresponds to index2, ... , GUTIn corresponds to indexn.

Before proceeding with additional description of FIG. 2, it is helpful to present some clarification on how the network 100 uses this list of identifiers for different types of paging:

1) The network 100 (e.g., AMF 190) assigns the GUTI list 205, which needs to be used for assigning next GUTI after an MT-EDT procedure. How the UE 110 and the network 100 gets the next GUTI from the list 205 based on an index are additional methods describe, e.g., in FIGS. 2, 2 A, and 2B.

2) The first page after the initial registration with the GUTI list 205 for paging (even if the first page is for MT-EDT) will use the normal GUTI assigned to the UE.

3) If the page is normal paging, the next GUTI is assigned via a GUTI re-allocation procedure as described below and herein.

4) If the page is MT-EDT paging, the next GUTI is assigned from the GUTI list as per the index derived using the techniques presented herein.

5) At any point in time, the UE 110 listens to only one GUTI in idle mode for paging reception. In block 220, the AMF 190 also assigns the hopping sequence 214 to the UE 110, where the hopping sequence 214 defines the sequence of GUTI indices to be followed for every subsequent MT-EDT procedure for re-assignment of GUTI. One example is a list 215-1, which is a new list of indices assigned to UE for MT-EDT purposes in addition to the normal GUTI. Each index corresponds to a GUTI in the list 205, and the example of list 215-1 would mean the AMF 190 (e.g., or other network node) would select the indexes in order from 1 (one) to n, barring a collision (as described below). Another option is illustrated where the hopping sequence 214 is a list 215-2, where the indexes from list 213 are “scrambled” as such: (Index2, Indexn, ..., Indexl}. That is, all the indexes from list 213 are randomized or otherwise rearranged in some order. In these examples, the AMF 190 would start at the first index in the list, and work through other indexes serially. For the list 215-2, this means the AMF 190 would use Index2 first, then Indexn, ..., finally using Indexl.

This example uses different lists 215 for different UEs 110. It is also possible for the AMF 190 to start with list 213 and use an algorithm to create a different list 215 for each UE in real time. In other words, the different lists 215 and indexes created for the lists could be created for each UE in real time, and actual “lists” would not have to be stored. For instance, the AMF 190 could run an algorithm that uses the list 213 to create Index2 for the first time the algorithm is used, then create IndexN the second time the algorithm is used, and so on. This effectively would create the list 215-2, but a list need not be actually created and stored.

The example of list 215-2 is useful in certain situations. For example, one option for block 220 is illustrated in block 223, where the AMF 190 assigns a same list of MT-EDT GUTIs across multiple UEs with different hopping sequences for effective utilization of GUTI identifiers. This is described also below, and applies to additional embodiments. Each UE can therefore be assigned indexes from list 213, but could be assigned different hopping sequences 214 as illustrated by an example where one UE is assigned list 215-1 and a second UE is assigned the index 215-2 (and other UEs would be assigned other lists 215 with different combinations of indexes to avoid collisions).

In block 225, the first paging message sent by the AMF 190 toward the UE 110 for MT-EDT will contain the S-TMSI corresponding to the latest GUTI assigned to the UE. In additional detail, the GUTI is the identifier of the UE which is used for paging the UE also (part of the GUTI, where S-TMSI is the identification in paging). After one page, as described previously, the UE 110 needs to be assigned a new identifier. Since there is no acknowledgement back from the UE, an implicit mechanism is proposed. So, the page message will contain a selected index, and after every page, a new GUTI = old GUTI + index, or selected as GUTI (index).

After successful completion of the MT-EDT procedure, both UE and the network internally re assign (see block 230) to the GUTI which corresponds to the selected index (from the list 215 of indexes) of the hopping sequence 214 from the MT-EDT GUTI list 205. For instance, if the AMF sends “Index2” in the paging message for block 227, both the UE 110 and the AMF can reassign to the GUTI2, which corresponds to Index2.

In block 235, for the subsequent paging messages for MT-EDT, the AMF 190 uses the S-TMSI corresponding to this new GUTI value. For non-EDT and MT-EDT paging messages, the S- TMSI corresponding to the current GUTI value is used, which may also be re-assigned as part of a GUTI re-allocation procedure. That is, once the GUTI is changed, the network has to use the new value of the GUTI as per the process already outlined while paging for normal data or MT-EDT.

The hopping sequence 214 (e.g., list 215 of indexes) or the list 205 of GUTIs reserved for MT- EDT can also be re-assigned, e.g., as part of a GUTI reallocation procedure or any other NAS procedure. See block 240.

The AMF can send an index for a hopping sequence 214 in the downlink (DL) MT-EDT message for a CIoT CP optimization solution within, e.g., a NAS message carrying the MT- EDT data. See block 245. In this way, the UE 110 and network 100 (e.g., the AMF190) also synchronously change the sequence in which the GUTI is assigned from the list 215 of indexes without initiating a GUTI reallocation procedure. It is noted that procedures for CP optimization and UP optimizations are described in 3GPP TS 23.502.

In case of AMF change, such as if the UE is new to this AMF 190, the new AMF 190 assigns a new hopping sequence 214 and/or GUTI list 205 (which overrides in the UE the previously stored one(s)). See block 250. In case of fallback to a connected mode during the MT-EDT procedure, the GUTI value which was used for the initial MT EDT paging which led to the fallback shall not be reused for the next MT-EDT paging (similar as if no fallback to connected would have taken place). See block 255. For instance, assume that a GUTI_X has been selected from the list 205 of GUTI values, based on an index in the hopping sequence 214, where “x” indicates one of the GUTI values. If there is a fallback, the GUTI_X will not be reused for the next MT-EDT paging.

Another possibility is illustrated in FIG. 2A, which describes derivation of a next GUTI index using NAS security keys and a formula for a CP solution in an exemplary embodiment. FIG. 2A is another logic flow diagram for GUTI reallocation for MT-EDT in 5GC and other systems. This figure further illustrates the operation of an exemplary method or methods, a result of execution of computer program instructions embodied on a computer readable memory, functions performed by logic implemented in hardware, and/or interconnected means for performing functions in accordance with exemplary embodiments. For instance, the control module 140 for the UE 110 and control module 151 for the AMF 190 may include operations multiples ones of the blocks in FIG. 2A, where each included block is an interconnected means for performing the function in the block. The operations in blocks in FIG. 2A are assumed to be performed by one or both of the UE 110, e.g., under control of the control module 140 at least in part or by the AMF 190, e.g., under control of the control module 151 at least in part.

In this exemplary method, the UE 110 and network 100 (e.g., the AMF 190) can internally select a (same) GUTI from the list 205 for every MT-EDT paging attempt involves, and this selection involves using the security digest generated for NAS Message containing the EDT payload along with a UE permanent identifier as parameters, where both the UE 110 and network 100 can derive the index for next GUTI to be used from the list 205. The next index to be used is derived based on the current GUTI. That is, the entities are using a formula, such as the new GUTI= old GUTI plus or minus a value; the formula is sent in the protected NAS message. This formula is merely an example, and other formulas may be used. Note that the formula could be relatively simple, such as “+value”, meaning that the value is added to the current GUTI to create the new GUTI, or “-value”, meaning that the value is subtracted from the current GUTI to create the new GUTI. The formula might also be more complex, or involve other values, such as values known only to the UE. In this case, the hopping sequence proposed in the method in FIG. 2 is not required, which increases efficiency, since the potentially long list 205 of GUTIs need not be sent. However, any steps not related to the hopping sequence may be applicable. For instance, the AMF 190 would still send a list 205 of GUTI values with the UE 110, as in block 210.

In FIG. 2A, blocks 210, 225, and 280 are the same as in FIG. 2. In block 257, the AMF sends a formula to derive the next GUTI in NAS paging message. In block 260, in response to the first paging message for MT-EDT, both the AMF and UE derive a next GUTI based at least on the formula.

In block 265, additional paging messages use the derived current GUTI (from block 260 or 265), and both AMF and UE derive another, next GUTI based at least on the formula as in block 260. Note that the formula might be the same each time, e.g., “+value” each time. The formula might be different each time, e.g., “+value” one time and “-2*value” the next time. In block 270 (similar to block 240 of FIG. 2 but without the hopping sequence), list 205 of GUTI values can be reassigned, e.g., as part of a GUTI reallocation procedure or any other NAS procedure. In block 275 (similar to block 250 of FIG. 2 but without the hopping sequence), if the UE is new to this AMF, the AMF 190 assigns a new list 205 of GUTI values, which overrides the old list in UE.

A further possibility is illustrated in FIG. 2B, which describes GUTI re-allocation for an UP MT-EDT solution. In UP EDT, the data is sent in a different path to the UE, and the AMF will know only after the successful delivery of the data. FIG. 2B is another logic flow diagram for GUTI reallocation for MT-EDT in 5GC and other systems. This figure further illustrates the operation of an exemplary method or methods, a result of execution of computer program instructions embodied on a computer readable memory, functions performed by logic implemented in hardware, and/or interconnected means for performing functions in accordance with exemplary embodiments. For instance, the control module 140 for the UE 110 and control module 151 for the AMF 190 may include operations multiples ones of the blocks in FIG. 2B, where each included block is an interconnected means for performing the function in the block. The operations in blocks in FIG. 2B are assumed to be performed by one or both of the UE 110, e.g., under control of the control module 140 at least in part or by the AMF 190, e.g., under control of the control module 151 at least in part. For this example of GUTI reallocation for MT-EDT using (e.g., a CIoT) UP solution, in case of an UP solution, the small data is sent from a UPF to an NG-RAN node (e.g., as all or part of RAN node 170 of FIG. 1) directly and the NG-RAN node sends the MT-EDT data using an UP solution, where the data is sent over radio bearers which are secured by AS security. Here, the NG-RAN node informs the successful completion of the transmission to the AMF 190 at the end of the MT-EDT data transfer from the RAN node 170 to the UE 110. Based on this indication, the AMF 190 internally selects a next index based on hopping sequence proposed in the method of FIG. 2. The UE 110 also uses a next index based on hopping sequence assigned.

In FIG. 2B, many of the blocks are the same as in FIG. 2 and will not be discussed. In block 280, the RAN node 170 sends data using the UP solution, and informs the AMF of successful completion (i.e., the UE has indicated (at the radio layer) the UE has received the data to the RAN node). In response to the indication of successful completion, in block 283, AMF reassigns to the GUTI value that corresponds to an index in the list 215 of indexes. In block 285, in response to completion of data reception, the UE 110 reassigns to the GUTI value that corresponds to the index in the list 215 of indexes.

Block 290 concerns subsequent paging. For additional paging messages, for MT-EDT, these use current GUTI for the current index, and both AMF and UE internally reassign to the GUTI value that corresponds to the next index in the list 215 of indexes as per blocks 280, 283, 285.

FIGS. 2, 2A, and 2B indicate possible methods for GUTI reallocation for MT-EDT in 5GC and other systems. One item addressed only briefly above (see block 223 in FIG. 2) is extension of the procedures provided above for reuse of GUTI list across multiple UEs. For instance, allocation of the list 205 of GUTIs for each UE 110 may require support of high number of GUTI sequences for MT-EDT purposes. This can be resolved with assigning a same GUTI list to multiple UEs but with different hopping sequence numbers assigned for each of them. This was briefly described above, with respect to block 223 of FIG. 2. With proper assignment of hopping sequence, the AMF 190 can avoid overlapping of identifiers across multiple devices. In case of collision detection anticipated by the AMF, the AMF 190 does not include the MT- EDT indicator towards the NG-RAN node so that the data transmission takes place using a transition via connected mode and GUTI re-allocation happens as defined for connected mode. Alternatively or additionally, if the AMF 190 needs to MT-EDT page a UE 110 with index N in the UE sequence and detects that the GUTI value associated with index N+l for this UE matches the GUTI value to be used for next MT EDT paging of another UE, the AMF may additionally send a hop value indication such as “hop=2” so that the UE would use after this MT EDT data transmission the GUTI value associated with index N+2 instead of the GUTI value associated with index N+l. See also description of this in FIG. 3, described below.

An exemplary signaling procedure for assignment of GUTI list for MT-EDT paging and implicit switching of GUTI after MT-EDT procedure is illustrated in FIG. 3. FIG. 3 is a signaling diagram for many of the operations previously described in reference to FIG. 2.

The signaling diagram in FIG. 3 illustrates signaling performed between the UE 110, a gNB (as RAN node) 170 and an AMF 190. Each of the signaling and operations in the blocks are assumed to be performed by the UE, gNB or AMF under corresponding control (at least in part) of a control module 140, 150, 151. This figure further illustrates the operation of an exemplary method or methods, a result of execution of computer program instructions embodied on a computer readable memory, functions performed by logic implemented in hardware, and/or interconnected means for performing functions in accordance with exemplary embodiments.

In signaling 310, there is a GUTI reallocation with the parameters of a GUTI, and GUTI-after- MT-EDT with a corresponding list of GUTIs. This is an example of a registration procedure from block 210 from FIG. 2. In signaling 315, the AMF 190 sends paging toward the gNB 170. This paging also includes the MD-EDT indicator and the identifier of the UE, illustrated as 5G- STMSI (5G SAE-temporary mobile subscriber identity). The paging also includes an indication (see reference 321) of the index from list 215 of the indexes. This corresponds to blocks 225 and 227 of FIG. 2B.

Signaling 320 is a random access (e.g., RACH) procedure including a Msg3 with a paging response, between the gNB 170 and the UE 110. The gNB 170 sends an N2-paging response message in signaling 325 to the AMF 190 to let the AMF know the paging was received by the UE. In response to receiving the signaling 325, the AMF in block 330 assigns the new value for the GUTI (corresponding to the index sent in 321) from the GUTI list 205 with a status waiting for UE confirmation. With respect to the status of waiting for the UE confirmation, the AMF 190 needs to know whether the paging was successful, and whether the UE did connect received the data, otherwise the AMF cannot assign new value for the GUTI. This knowledge is achieved in an indirect way, using Msg3 (see signaling 320), which is an RRC message from the UE to the gNB. On receiving the Msg3 from UE, the gNB 170 informs the AMF 190 that the paging was successful, upon which AMF and UE internally assigns the new value. Note that FIG. 3 illustrates block 330 as being after N2-Paging-Response in signaling 325, which means there was a UE confirmation.

In signaling 335, the AMF 190 sends the MD-EDT data as a DL NAS message. This includes (see reference 338) the AMF using the GUTI corresponding to the index in signaling 320, but includes a new index into the list 205 of GUTI values. The gNB 170 sends the data in an early - data-complete message in signaling 340. The gNB 170 sends a delivery confirmation of EDT to the AMF 190 in signaling 345.

In response to receiving the delivery confirmation, the AMF reassigns (block 350) the GUTI to the new value from the GUTI-after-MT-EDT list sent in signaling 310. This corresponds to block 235 of FIG. 2.

In response to the early-data-complete message in signaling 340, the UE releases to idle mode in block 355. In FIG. 3, the UE is in Idle mode, but temporarily connects to the gNB and falls back to Idle mode in block 355. The UE 110 also uses (see block 360) the next index in the GUTI-after-MT-EDT list as its GUTI for further NAS processing. This is another illustration of block 235 of FIG. 2.

The signaling message sequence given in FIG. 3 is with reference to UE using CP-CIoT- Optimization. In the procedure of FIG. 3, the DL NAS message in signaling 335 may also include a parameter 336 (called the “hopping sequence parameter 336”) to change the hopping sequence within the MT-EDT GUTI list. This parameter 336 provides a “hop” in the hopping sequence that is ordered to the UE if the AMF detects that the GUTI value to be used for next paging after the current MT EDT transmission collides with the GUTI value to be used at a next MT EDT paging for another UE. See block 351. A collision can happen if the AMF sends the same hoping sequence to multiple UEs and a same GUTI was potentially selected for more than one UE. In this case, one of the UEs needs to be given a new value indicated by the index. The hopping sequence parameter 336 is, in an exemplary embodiment, a different index from a list 215. That is, if the next index is supposed to be Indexy, and there is a possible collision, the AMF 190 could use Indexy+1 instead of Indexy. Alternatively, the index to be used for getting the GUTI from the MT-EDT GUTI list can also be derived from the NAS security context available both at the UE and the AMF or the index can be included in the security protected DL NAS message. The index of next GUTI is derived from the integrity protection info generated. For example, it could be some or all bits of the integrity protection value. Or the index can be included in the NAS message, which is integrity protected.

The solution can be extended to an UP solution also as such with the gNB 170 informing the confirmation of EDT data delivery to the AMF 190 so that the AMF can switch to new GUTI from the MT-EDT GUTI list.

FIGS. 2 and 2B consider that the UE gets assigned a selected index from a hopping sequence 214 which in an exemplary embodiment is a list 215 of indexes, but the UE 110 does not have a copy of the indexes. For example, assume the hopping sequence 214 is { 1, 3, 5, 7, 2, 4, 6, 8} for indexes for GUTIs 1 through 8. In FIG. 2, the AMF would send “1” (indicating GUTI1) as an index to be used for an MT-EDT paging, then “3” (indicating GUTI3), then “5” (indicating GUTI5). It is also possible, however, that the AMF could send the entire hopping sequence once, then both the UE and the AMF would know the hopping sequence and could select the first index (1), then the second index (3), then the third index (5),... for each MT-EDT paging. For this example, the AMF’s collision avoidance process could send a “skip next index” in an MT-EDT page as the hopping sequence parameter 336 (see FIG. 3). This would cause the UE 110 to skip the next index in its list 215 of indexes.

Exemplary embodiments include and disclose one or more of the following technical effects and advantages. 1) Methods were disclosed where an AMF assigns a list of GUTIs to be used across MT-EDT paging messages for UEs capable of MT-EDT as part of GUTI reallocation procedure or any other NAS messages.

2) Methods were disclosed where the TIE and AMF switch to new GUTI within the list allocated for MT-EDT for the subsequent MT EDT paging, after successful MT-EDT procedure or even in case of fallback to connected mode. Here, explicit GUTI reallocation as part of MT-EDT signaling procedure is avoided and implicitly both UE and AMF select a new GUTI.

3) Methods were disclosed where the UE and AMF use different hopping sequences for rotating the identifier within the list of MT-EDT GUTI for enhanced security. The AMF can re-assign the hopping sequence as part of MT-EDT downlink NAS message itself, in an exemplary embodiment.

4) Methods were disclosed where the UE and AMF switch the GUTI within the MT-EDT list implicitly after every MT-EDT data transmission for a CIoT UP solution.

5) Methods were disclosed where UE and AMF derive the next GUTI index based on the NAS security digest information included in the downlink EDT NAS message for a CIoT CP Solution.

6) Methods were disclosed at the AMF, where AMF can manage to assign a same list of MT- EDT GUTIs across multiple UEs with different hopping sequences for effective utilization of GUTI identifiers.

7) Methods were disclosed at the AMF where a “hop” in the hopping sequence can be ordered to the UE or a new hopping sequence configured if the AMF detects that the GUTI value to be used for next paging after the current MT EDT transmission collides with the GUTI value to be used at a next MT EDT paging for another UE.

The following are additional examples. Example 1. A method, comprising: in a network node in a wireless network, communicating with a user equipment in the wireless network to set a plurality of identifiers to be used for paging after early data transfer procedures to transfer data to the user equipment using random access procedures, the identifiers identifying at least the user equipment for the early data transfer procedures; and performing early data transfer procedures to transfer data from the network node to the user equipment using corresponding multiple ones of the identifiers.

Example 2. The method of example 1, wherein performing early data transfer procedures to transfer data from the network node to the user equipment comprises: determining, for an individual one of the early data transfer procedures and from a plurality of values of a hopping sequence, a value of the hopping sequence; using the value of the hopping sequence to determine a corresponding one of the plurality of identifiers; and performing at least paging followed by the early data transfer using the determined one of the identifiers.

Example 3. The method of example 2, wherein: the plurality of values of a hopping sequence comprise a list of indexes; the determined one of the identifiers is a determined one of the indexes; and the plurality of identifiers correspond to the plurality of indexes, and the determined one of the indexes selects one of the plurality of identifiers.

Example 4. The method of example 3, wherein the user equipment is one of multiple user equipment, and wherein the method further comprises the network node assigning a same list of identifiers across multiple user equipment, with different hopping sequences for each of the multiple user equipment, and wherein the network node uses a corresponding one of the hopping sequence for a given user equipment for at least the paging for the early data transfer procedures for that given user equipment.

Example 5. The method of any of examples 2 to 4, wherein performing early data transfer procedures further comprises, for one of the early data transfer procedures: the network node receives an indication from another network node that the individual one of the early data transfer procedures been completed; and responsive to reception of the indication, determining, for the individual one of the early data transfer procedures, the value of the hopping sequence.

Example 6. The method of any of examples 2 to 5, wherein the plurality of identifiers are in a sequence and performing early data transfer procedures comprises: determining there is a possible collision for an upcoming data transfer procedure between identifiers used for the user equipment and another user equipment; and sending an indication to the user equipment to skip at least the identifier in the sequence that is determined to correspond to the upcoming data transfer procedure and instead cause a different identifier in the sequence to be used for the upcoming data transfer procedure.

Example 7. The method of any of examples 2 to 5, wherein the plurality of identifiers are in a sequence and performing early data transfer procedures comprises: determining there is a possible collision for an upcoming data transfer procedure between identifiers used for the user equipment and another user equipment, based on a same index for the hopping sequence being used for the user equipment and the other user equipment; selecting an index in the hopping sequence to use to skip at least the identifier in the hopping sequence that is determined to correspond to the upcoming data transfer procedure; and sending an indication to the user equipment of the selected index.

Example 8. The method of example 1, wherein performing early data transfer procedures comprises deriving individual identifiers for individual ones of the early data transfer procedures at least by using one or more formulas.

Example 9. The method of example 8, further comprising sending by the network node one or more indications of the one or more formulas to the user equipment.

Example 10. The method of any of examples 1 to 9, wherein the performing early data transfer procedures further comprises: in response to fallback by the user equipment into connected mode for a given one of the early data transfer procedures that used a given one of the identifiers, using a different one of the identifiers for a next early data transfer procedure that occurs after the given one of the early data transfers.

Example 11. The method of any of examples 1 to 10, wherein the identifiers are global unique temporary identifiers, which comprise a unique identifier identifying an access and mobility management function, and an identifier intended to uniquely identify the user equipment, and wherein the network node comprises the access and mobility management function.

Example 12. An apparatus comprising means for performing: communicating, in a network node in a wireless network, with a user equipment in the wireless network to set a plurality of identifiers to be used for paging after early data transfer procedures to transfer data to the user equipment using random access procedures, the identifiers identifying at least the user equipment for the early data transfer procedures; and performing early data transfer procedures to transfer data from the network node to the user equipment using corresponding multiple ones of the identifiers.

Example 13. The apparatus of example 12, further comprising means for performing any of the methods of examples 2 to 11.

Example 14. An apparatus, comprising: one or more processors; and one or more memories including computer program code, wherein the one or more memories and the computer program code are configured, with the one or more processors, to cause the apparatus to perform operations comprising: in a network node in a wireless network, communicating with a user equipment in the wireless network to set a plurality of identifiers to be used for paging after early data transfer procedures to transfer data to the user equipment using random access procedures, the identifiers identifying at least the user equipment for the early data transfer procedures; and performing early data transfer procedures to transfer data from the network node to the user equipment using corresponding multiple ones of the identifiers. Example 15. The apparatus of example 14, wherein the one or more memories and the computer program code are further configured, with the one or more processors, to cause the apparatus to perform operations in any of the methods of examples 2 to 11.

Example 16. A computer program, comprising code for performing the methods of any of examples 1 to 11, when the computer program is run on a computer.

Example 17. The computer program according to example 16, wherein the computer program is a computer program product comprising a computer-readable medium bearing computer program code embodied therein for use with the computer.

Example 18. The computer program according to example 16, wherein the computer program is directly loadable into an internal memory of the computer.

As used in this application, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and/or digital hardware circuit(s) with software/firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.”

This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device. Embodiments herein may be implemented in software (executed by one or more processors), hardware (e.g., an application specific integrated circuit), or a combination of software and hardware. In an example embodiment, the software (e.g., application logic, an instruction set) is maintained on any one of various conventional computer-readable media. In the context of this document, a “computer-readable medium” may be any media or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer, with one example of a computer described and depicted, e.g., in FIG. 1. A computer-readable medium may comprise a computer-readable storage medium (e.g., memories 125, 155, 171 or other device) that may be any media or means that can contain, store, and/or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. A computer-readable storage medium does not comprise propagating signals.

If desired, the different functions discussed herein may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the above-described functions may be optional or may be combined.

Although various aspects are set out above, other aspects comprise other combinations of features from the described embodiments, and not solely the combinations described above.

It is also noted herein that while the above describes example embodiments of the invention, these descriptions should not be viewed in a limiting sense. Rather, there are several variations and modifications which may be made without departing from the scope of the present invention.

The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows:

3 GPP third generation partnership project

5G fifth generation

5GC 5G core network

AMF access and mobility management function

AS access stratum CIoT cellular Internet of things

CM control module

CP control plane

CU central unit

DL downlink

DU distributed unit

EDT early data transfer eNB (or eNodeB) evolved Node B (e.g., an LTE base station)

EN-DC E-UTRA-NR dual connectivity en-gNB or En-gNB node providing NR user plane and control plane protocol terminations towards the UE, and acting as secondary node in EN-DC

E-UTRA evolved universal terrestrial radio access, i.e., the LTE radio access technology gNB (or gNodeB) base station for 5G/NR, i.e., a node providing NR user plane and control plane protocol terminations towards the UE, and connected via the NG interface to the 5GC GUAMI globally unique AMF identifier

GUTI global unique temporary identifier

I/F interface

LTE long term evolution

MAC medium access control

MME mobility management entity

MO-EDT Mobile originated Early data transmission

NAS non-access stratum ng or NG next generation ng-eNB or NG-eNB next generation eNB NR new radio

N/W orNW network

PDCP packet data convergence protocol

PHY physical layer

RACH random access channel

RAN radio access network Rel release

RLC radio link control

RRH remote radio head

RRC radio resource control

RU radio unit

Rx receiver

SAE system architecture evolution

SDAP service data adaptation protocol

SGW serving gateway

SMF session management function

S-TMSI SAE-temporary mobile subscriber identity

TS technical specification

Tx transmitter

UE user equipment (e.g., a wireless, typically mobile device)

UP user plane

UPF user plane function

Claims

1. A method, comprising: in a network node in a wireless network, communicating with a user equipment in the wireless network to set a plurality of identifiers to be used for paging after early data transfer procedures to transfer data to the user equipment using random access procedures, the identifiers identifying at least the user equipment for the early data transfer procedures; and performing early data transfer procedures to transfer data from the network node to the user equipment using corresponding multiple ones of the identifiers.

2. The method of claim 1, wherein performing early data transfer procedures to transfer data from the network node to the user equipment comprises: determining, for an individual one of the early data transfer procedures and from a plurality of values of a hopping sequence, a value of the hopping sequence; using the value of the hopping sequence to determine a corresponding one of the plurality of identifiers; and performing at least paging followed by the early data transfer using the determined one of the identifiers.

3. The method of claim 2, wherein: the plurality of values of a hopping sequence comprise a list of indexes; the determined one of the identifiers is a determined one of the indexes; and the plurality of identifiers correspond to the plurality of indexes, and the determined one of the indexes selects one of the plurality of identifiers.

4. The method of claim 3, wherein the user equipment is one of multiple user equipment, and wherein the method further comprises the network node assigning a same list of identifiers across multiple user equipment, with different hopping sequences for each of the multiple user equipment, and wherein the network node uses a corresponding one of the hopping sequence for a given user equipment for at least the paging for the early data transfer procedures for that given user equipment.

5. The method of any of claims 2 to 4, wherein performing early data transfer procedures further comprises, for one of the early data transfer procedures: the network node receives an indication from another network node that the individual one of the early data transfer procedures been completed; and responsive to reception of the indication, determining, for the individual one of the early data transfer procedures, the value of the hopping sequence.

6. The method of any of claims 2 to 5, wherein the plurality of identifiers are in a sequence and performing early data transfer procedures comprises: determining there is a possible collision for an upcoming data transfer procedure between identifiers used for the user equipment and another user equipment; and sending an indication to the user equipment to skip at least the identifier in the sequence that is determined to correspond to the upcoming data transfer procedure and instead cause a different identifier in the sequence to be used for the upcoming data transfer procedure.

7. The method of any of claims 2 to 5, wherein the plurality of identifiers are in a sequence and performing early data transfer procedures comprises: determining there is a possible collision for an upcoming data transfer procedure between identifiers used for the user equipment and another user equipment, based on a same index for the hopping sequence being used for the user equipment and the other user equipment; selecting an index in the hopping sequence to use to skip at least the identifier in the hopping sequence that is determined to correspond to the upcoming data transfer procedure; and sending an indication to the user equipment of the selected index.

8. The method of claim 1, wherein performing early data transfer procedures comprises deriving individual identifiers for individual ones of the early data transfer procedures at least by using one or more formulas.

9. The method of claim 8, further comprising sending by the network node one or more indications of the one or more formulas to the user equipment.

10. The method of any of claims 1 to 9, wherein the performing early data transfer procedures further comprises: in response to fallback by the user equipment into connected mode for a given one of the early data transfer procedures that used a given one of the identifiers, using a different one of the identifiers for a next early data transfer procedure that occurs after the given one of the early data transfers.

11. The method of any of claims 1 to 10, wherein the identifiers are global unique temporary identifiers, which comprise a unique identifier identifying an access and mobility management function, and an identifier intended to uniquely identify the user equipment, and wherein the network node comprises the access and mobility management function.

12. An apparatus comprising means for performing: communicating, in a network node in a wireless network, with a user equipment in the wireless network to set a plurality of identifiers to be used for paging after early data transfer procedures to transfer data to the user equipment using random access procedures, the identifiers identifying at least the user equipment for the early data transfer procedures; and performing early data transfer procedures to transfer data from the network node to the user equipment using corresponding multiple ones of the identifiers.

13. The apparatus of claim 12, further comprising means for performing any of the methods of claims 2 to 11.

14. An apparatus, comprising: one or more processors; and one or more memories including computer program code, wherein the one or more memories and the computer program code are configured, with the one or more processors, to cause the apparatus to perform operations comprising: in a network node in a wireless network, communicating with a user equipment in the wireless network to set a plurality of identifiers to be used for paging after early data transfer procedures to transfer data to the user equipment using random access procedures, the identifiers identifying at least the user equipment for the early data transfer procedures; and performing early data transfer procedures to transfer data from the network node to the user equipment using corresponding multiple ones of the identifiers.

15. The apparatus of claim 14, wherein the one or more memories and the computer program code are further configured, with the one or more processors, to cause the apparatus to perform operations in any of the methods of claims 2 to 11.

16. A computer program, comprising code for performing the methods of any of claims 1 to 11, when the computer program is run on a computer.

17. The computer program according to claim 16, wherein the computer program is a computer program product comprising a computer-readable medium bearing computer program code embodied therein for use with the computer.

18. The computer program according to claim 16, wherein the computer program is directly loadable into an internal memory of the computer.