WO2020002703A1

WO2020002703A1 - Enhanced communication with a network

Info

Publication number: WO2020002703A1
Application number: PCT/EP2019/067582
Authority: WO
Inventors: Jouni Korhonen; Tuomo KUMENTO
Original assignee: Nordic Semiconductor Asa
Priority date: 2018-06-29
Filing date: 2019-07-01
Publication date: 2020-01-02
Also published as: GB201810764D0

Abstract

A method of obtaining an information feature in a wireless communication system comprising a wireless network (106, 304) and at least one device (102, 302) capable of connecting to the network (106, 304) is provided. The method comprises the device (102, 302) requesting an information feature support indication from the network (106, 304) in a first message (306) with a first format type, the network (106, 304) sending said information feature support indication to the device (310), and the device, after receiving the information feature support indication, requesting the information feature from the network that is indicated by the information feature support indication in a second message (312) having a second format type.

Description

Enhanced communication with a network

Technical field This invention relates to communication between mobile devices and a network, and more specifically to devices obtaining additional information‘features’ from a network.

Background In mobile telecommunication systems, such as a Long Term Evolution (LTE) network, User Equipment (UE) is required to set up a new connection with the network, for example, every time the UE switches on. As more and more UEs become internet connected, setting up this initial connection often requires additional information from the network, in order to carry out correctly, for example, IP configuration. In order to obtain such additional information, the UE will typically send a Protocol Configuration Options (PCO) request to the network, together with relevant Evolved Packet System (EPS) Session Management (ESM) messages piggybacked, for example, within an Attach Request message. A PCO request contains a list of blank fields, each relating to a piece of information that the UE wishes to know, for example, a Domain Name System (DNS) server address. The network would then return this information in a relevant ESM message, for example, piggybacked in an Attach Accept message, in order to allow the UE to properly configure its connection, before finalising the connection to the network by sending an Attach Complete message. Whilst PCO is variable in the sense that UEs can request any selection or all of the potential fields for information from a network, it has a fixed structure and a specifically limited length, and is therefore limited to the fields predefined in the 3GPP standard. In older systems, PCO was adequate to obtain enough information for sufficient network connection configuration. However, as times have moved on, and technologies advanced, PCO may now no longer have sufficient capacity to carry required information in certain cases. As a result, extended Protocol Configuration Options (ePCO) was developed, thus allowing a UE to potentially obtain much more information from a network than was previously possible with just PCO. However, as ePCO is structured in a different way, the two formats are not compatible - e.g. sending an ePCO request to a network that only supports PCO would simply return no information. This is clearly undesirable from the UE’s point of view. Furthermore, the 3GPP standard defined by Release 13 in TS24.301 and TS24.008 states that when supported by a network and a UE, ePCO must be used over PCO.

A problem therefore arises when a UE attempts to connect to a new, unknown network, and does not know if the new network supports ePCO or not. In the current 3GPP standard, during an initial connection establishment, PCO / ePCO requests can only be made to the network before discovery of which version of PCO / ePCO the network supports. As an example, a device could assume that a new network supports ePCO, and make an ePCO request in an Attach Request message. The network in this example does not in fact support ePCO, and thus cannot return the ePCO request. In this case, the ePCO request simply goes unanswered from the UEs perspective, and the device must either continue with the attach procedure with, for example, an incomplete IP configuration, or cancel the attachment procedure and reattach with the knowledge that the network does not support ePCO, instead using a legacy PCO request, which clearly adds time and power consumption. In the case where the device continues with, for example, an incomplete IP configuration, it is likely that the device will encounter errors in operation later in the connection.

The present invention seeks to address at least some of the problems described above.

Summary

From a first aspect, the invention provides a method of obtaining an information feature in a wireless communication system comprising a wireless network and at least one device capable of connecting wirelessly to said network, the method comprising: the device requesting an information feature support indication from the network in a first message having a first format type;

the network sending said information feature support indication to the device; the device, after receiving the information feature support indication, requesting the information feature from the network that is indicated by the information feature support indication in a second message having a second format type.

From a second aspect, the invention provides a wireless network and at least one device capable of connecting wirelessly to said network, wherein:

the device is configured to request an information feature support indication from the network in a first message having a first format type;

the network is configured to send said information feature support indication to the device;

the device is configured, after receiving the information feature support indication, to request the information feature from the network that is indicated by the information feature support indication in a second message having a second format type.

Thus, it will be seen by those skilled in the art that in accordance with at least embodiments of the invention there is provided a method that provides additional information feature support to a device connecting to a network, by first letting the device know if the information feature is supported. This may be advantageous as it may save power and time for both the network and the device. The present invention may also prevent the scenario whereby the device continues with no information feature support, which is disadvantageous, for example, because the device may have an incomplete connection configuration due to the lack of feature support.

The present invention may further allow the device to ensure a proper configuration, without needing to maintain a cache or history of feature support in various networks, as the information feature support can be discovered upon connection.

In some embodiments, the device configures its connection based on the information feature requested from the network, after receiving said information feature. This enables the device to correctly configure, for example, its IP configuration with the network.

In some embodiments, the wireless network is selected from the group comprising an LTE telecommunication network, an NB-loT network, or an eMTC network. In some embodiments, the information feature is PCO or ePCO. By extension, the feature support information may be PCO support information or ePCO support information. In these embodiments, the device can ensure that its connection configuration is set up correctly through the use of PCO / ePCO. In this way, for example, a correct IP configuration can be ensured for a device’s connection to the network. As PCO and ePCO are incompatible, the device can learn which version is supported by the network before requesting either. This allows for the device to ensure that the correctly supported version is requested, leading to a correct connection configuration. Furthermore, these embodiments may allow for the device to conform to the 3GPP standard defined by Release 13 in TS24.301 and TS24.008, by ensuring that when supported, ePCO is used over PCO.

In some embodiments, the first message is an Attach Request message. Specifically, this may entail the device including the‘ESM Information Transfer Flag’ Information Element (IE) in the PDN Connectivity Request message within the Attach Request message.

In some embodiments, the Attach Request message contains no PCO or ePCO requests. This ensures that the device is not supplied with an incorrect PCO / ePCO response, before it has learned of the network support for such features. For example, if the device were to request PCO, whilst supporting ePCO itself, and the network also supports ePCO, then the network would have to break the 3GPP standard defined by Release 13 in TS24.301 and TS24.008 (ePCO must be used over PCO when supported) in order to fulfil the response. Alternatively, if the device were to request ePCO, but the network only supports PCO, then the ePCO request would not be fulfilled, and the device would be left with no information.

In some embodiments, the information feature support indication is sent to the device in an ESM Information Request message from the network. This may require a change to the 3GPP standard presently in force, as the ESM Information Request message is extended to include an“EPS Network Feature support” IE, which contains the feature support information. In embodiments where the feature is PCO / ePCO, the EPS network support IE includes the ePCO support flag. ln some embodiments, the second message is an ESM Information Response message. In these embodiments, the device may request the feature before the final Attach Accept and Attach Complete messages, i.e. at the last opportunity before the connection is completed.

In some embodiments, the requested information feature is provided to the device in an Attach Accept message.

The invention also extends to a device, configured for use in a wireless

telecommunication system comprising a wireless network, the device being configured to:

request ePCO support information from the wireless network in a first message;

receive ePCO support information from the wireless network;

request PCO or ePCO from the network depending on the ePCO support information received.

Features of any aspect or embodiment described herein may, wherever appropriate, be applied to any other aspect or embodiment described herein. Where reference is made to different embodiments or sets of embodiments, it should be understood that these are not necessarily distinct but may overlap.

Brief description of the Drawings

Certain preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Fig. 1 is a schematic representation of a device and network system in accordance with an embodiment of the invention.

Fig. 2 is a prior art representation of a typical User Equipment attach procedure to a network.

Fig. 3 is a representation of a User Equipment attach procedure to a network in accordance with an embodiment of the invention.

Detailed description Fig. 1 shows a schematic representation of a device and network system in accordance with an embodiment of the invention. In this embodiment, the device is a User Equipment (UE) 102, which connects to a network 106 via a base station 104. The UE 102 communicates directly with the base station 104, which may be one of many base stations, depending on the physical location of the UE 102. Messages from the UE 102 are then passed to the network 106 by the base station, and vice versa, to allow communication. Fig. 2 shows a prior art representation of a typical User Equipment (UE) 202 attach procedure to a network 204, for example a MME (Mobility Management Entity). The UE 202 may enter a new network domain, and thus be required to establish a new connection with the network 204. Initially, the UE 202 does not know whether or not the network 204 supports PCO or ePCO. As the information gained from PCO / ePCO is necessary for the UE 202 to set up a complete IP configuration, the UE 202 must assume the network 204 will support one or the other. Based on the Radio Access Network (RAN) capabilities, the UE 202 can make a best guess as to which version of PCO is supported. In either case, the UE 202 can begin the attach procedure with the network by sending an Attach Request message 206, including a PCO or ePCO request.

At the next step, both the network 204 and the UE 202 authenticate 208 with each other, and exchange security mode commands. Specifically, the messages sent are an Authentication Request from the network 204 to the UE 202, and an Authentication Response from the UE 202 to the network 204. This is followed by a Security Mode Command message from the network 204 to the UE 202, and a Security Mode Response form the UE 202 to the network 204. These messages set up secure communication between the UE 202 and the network 204. Next, the network 204 sends an Attach Accept message 210 to the UE 202, which includes any PCO or ePCO that the UE 202 initially requested. However, if the UE 202 requested PCO, and both the network 204 and UE 202 support ePCO, then the network 204 must either break the 3GPP standard defined by Release 13 in TS24.301 and TS24.008 to respond (ePCO must be used over PCO where supported), or not respond at all, leaving the UE 202 with no information, and an incomplete IP configuration. On the other hand, if the UE 202 requested ePCO, and the network 204 only supports PCO, then the network 204 will simply not recognise the request, and return nothing. In this case too, the UE 202 is left with insufficient information to set up a correct connection with the network 204. In the scenario where the UE 202 requests the correct version of PCO / ePCO, then the request is fulfilled by the network in the Attach Accept message 210, and the UE 202 can configure its connection correctly.

In any of the above cases, it is at this stage (Attach Accept message 210) where the UE 202 learns of the network support for PCO or ePCO. Crucially, this is after any potential messages from the UE 202 containing PCO or ePCO requests.

Finally, the UE 202 sends an Attach Complete message 212 to the network 204, finalising the connection between the UE 202 and the network 204, allowing for subsequent communication as standard. However, in the cases described above where the UE 202 is left with an unfulfilled PCO / ePCO request, the UE 202 has two options. The UE 202 can continue in its current state, with an incomplete configuration, and potentially run into errors in future communications where a correct configuration is required. Alternatively, the UE 202 can detach from the network, and restart the attach procedure, this time with the knowledge of the network PCO / ePCO support. This alternative is disadvantageous as it wastes time and power for both the network 204 and the UE 202.

Fig. 3 shows a representation of a User Equipment (UE) 302 attach procedure to a network 304 in accordance with an embodiment of the invention. This embodiment will be described herein with reference to the above description of Fig. 2, with some key differences.

In this embodiment, as before, the UE 302 may enter a new network domain, and thus be required to establish a new connection with the network 304. Similarly to the prior art case, the UE 302 does not know whether or not the network supports PCO or ePCO. However, in this embodiment, the UE 302 does not include any PCO or ePCO requests in its Attach Request message 306, but does include an ESM Information Transfer Flag (usually optional). The Attach Request message 306 represents a first message having a first format type. The Authentication and Security Mode procedures 308 are the same here as in Fig. 2.

As the ESM Information Transfer Flag was included in the Attach Request message 306 from the UE 302, the next communication is an ESM Information Request message 310 from the network 304 to the UE 302. This message contains other additional information that the UE may have wished to learn, but this message is modified from the 3GPP standard defined by Release 13. Specifically, the ESM Information Request message 310 is extended with the‘EPS Network Feature

Support’ Information Element (IE), containing an ePCO support flag. This flag tells the UE 302 if the network 304 supports ePCO, or just PCO.

The UE 302 responds to this message with an ESM Information Response message 312, which includes the correct type of PCO / ePCO request indicated by the ePCO support flag. The ESM Information Response message 312 represents a second message having a second format type.

The network 304 can then fulfil this request in the subsequent Attach Accept message 314. The PCO / ePCO request that is sent to the network 304 is guaranteed to be the version that the network 304 supports. Finally, with the correct information supplied in the Attach Accept message 314, the UE 302 can configure its connection fully, and proceed with an Attach Complete message 316. This approach mitigates the two scenarios described above with reference to Fig. 2, by ensuring that a UE 302 will have a complete connection configuration, including any IP configuration etc. for use in subsequent communications with the network 304. This approach also guarantees that ePCO will be used over PCO where supported. There is no need to transfer“EPS network feature support” IE again in the message 314 as it has already been delivered in the message 310.

It will be appreciated by those skilled in the art that the invention has been illustrated by describing one or more specific embodiments thereof, but is not limited to these embodiments; many variations and modifications are possible, within the scope of the accompanying claims.

Claims

1. A method of obtaining an information feature in a wireless communication system comprising a wireless network and at least one device capable of connecting wirelessly to said network, the method comprising:

the device requesting an information feature support indication from the network in a first message having a first format type;

2. The method of claim 1 , wherein the method further includes the device configuring its connection based on the information feature requested from the network, after receiving said information feature.

3. The method of claim 1 or 2, wherein the network is selected from the group comprising an LTE telecommunication network, an NB-loT network, or an eMTC network.

4. The method of any preceding claim, wherein the information feature is Protocol Configuration Options or extended Protocol Configuration Options.

5. The method of any preceding claim, wherein the first message is an Attach Request message.

6. The method of claim 5, wherein the Attach Request message contains no Protocol Configuration Options or extended Protocol Configuration Options requests.

7. The method of any preceding claim, wherein the information feature support indication is sent to the device in an Evolved Packet System Session Management Information Request message from the network.

8. The method of any preceding claim, wherein the device requests the feature in an Evolved Packet System Session Management Information Response message.

9. The method of any preceding claim, wherein the second message is an Evolved Packet System Session Management Information Response message.

10. The method of any preceding claim, further comprising the network sending the requested information feature to the device in an Attach Accept message.

1 1. A wireless network and at least one device capable of connecting wirelessly to said network, wherein:

12. A device, configured for use in a wireless telecommunication system comprising a wireless network, the device being configured to:

request extended Protocol Configuration Options support information from the wireless network in a first message;

receive extended Protocol Configuration Options support information from the wireless network;

request Protocol Configuration Options or extended Protocol Configuration

Options from the network depending on the extended Protocol Configuration Options support information received.