TECHNICAL FIELD

The present disclosure relates to reporting measurement data. More particularly, the present disclosure relates to arrangements and methods for reporting of measurement data from a user equipment to a receiving entity via a network node comprised in a wireless communication system.

BACKGROUND

For next generation of mobile telecommunications systems the 3 ^rd

Generation Partnership Project (3GPP) is in the process of defining solutions for user equipment (UE) measurement logging function and immediate reporting function called Minimizing Drive Tests (MDT) . The MDT study aims at assessing the feasibility, benefits and complexity of automating the collection of UE measurements to minimize the need of manual drive-tests.

The work under the MDT study should define use cases and requirements for minimizing drive-tests in next generation LTE/HSPA (Long Term Evolution /High Speed Packet Access) networks. Also, based on the defined use cases and requirements, the MDT should focus on study the necessity of defining new UE measurements logging and reporting capabilities for minimizing drive tests and analyze the impact on the UE.

The use cases for the MDT will be given as following.

• Radio coverage optimization

« Mobility optimization

· Network capacity optimization

« Parameterization for common channels

« Quality of Service verification

The network can request the UE to perform logging of measurements. The UE executes measurements and logs these measurements internally in a sequential manner, containing e.g. some hour of logged measurement information. When the UE has logged measurements the UE indicates to the network that it has an available measurement log. The network may then request the UE to deliver the measurement log. This prior art procedure is illustrated in Figure 1. The UE sends 10 an indication to a network node, e.g. an eNodeB comprised in a LTE system or a RNC (Radio Network Controller) comprised in a WCDMA system, that it has an available measurement log. The network node then determines 11 whether is wants to request the measurement log. If it determines to request the measurement log it sends 12 a request to the UE. Thereupon the UE delivers 13 the measurement log to the network node. From the eNB/RNC, the received measurement log is sent to an OAM

(Operation and Maintenance) or similar server (not shown) comprised in the network.

The network collects measurement logs from several UEs in different cells. By collecting and retrieving information from the measurement logs the network is able to perform optimization of radio coverage, mobility, network capacity and to perform parameterization for common channels and verification of QoS.

The current 3 GPP assumptions on the measurement log feature are: o The UE is required to maintain only one measurement log at a time. o The measurement log only contains measurement information collected in one RAT (Radio Access Technology). The RAT being the type of radio technology used in a Radio Access Network (RAN) to access the Core Network (CN) in the wireless communication system, e.g., UMTS, GSM/EDGE, CDMA2000, WiMAX.

o If the UE is requested to start logging measurements, a previously stored measurement log in the UE is erased.

The current 3GPP assumption is that the MDT measurements are reported in the same RAT as they have been measured in. If the measurement log can only be reported in the RAT where the measurements are collected, a number of measurements can be lost or delayed for such a long time that they are not usable. The reasons why a UE may not stay in one and the same RAT are mainly related to network deployment and service provisioning. An existing operator's network is often a combination of two or three RATs and designed to work together in order to maximize the service offerings and geographical coverage area in a cost efficient way. This often means that there is not a uniform coverage of the different RATs (one RAT can have spotty coverage while the others are more globally available, e.g. because of propagation characteristics and/ or service reasons). There are also various load balancing schemes used by an operator that also will make a UE move between RATs. The detailed measurements stored in the measurement log are typically RAT-specific. Consequently, the reporting of the measurements in another RAT than in which they were collected would not be understood. Moreover, it is neither possible to send the reported measurement log to another RAT to e.g. convey the information to the right place.

Another consequence of the current 3GPP assumption that the MDT measurements are reported in the same RAT as they have been measured in is, for the case where a UE has been logging measurements in one RAT, that these cannot be delivered in case the UE re-selects to another RAT. Furthermore, in case the UE is requested to perform logging of measurements in the new re-selected RAT, the measurement log stored while the UE was in the old RAT will be lost. Hence, resources are wasted.

SUMMARY

The object of the present embodiments is to address some of the problems and disadvantages outlined above, and to provide improved methods and arrangements for reporting measurement logs in a wireless communication system.

The above stated object is achieved by means of the methods and the arrangements according to the independent claims. In accordance with a first aspect of embodiments, a method in a user equipment for reporting measurement is provided. The user equipment is configured to communicate with a wireless communication system. The method comprising including measurement information in a message, wherein the measurement information is collected in a first RAT. The method further comprising transmitting the message to a receiving entity comprised in the wireless communication system via a network node utilizing a second RAT, wherein the second RAT is different from the first RAT.

In accordance with a second aspect of embodiments, a method in a network node for reporting measurement is provided. The network node is comprised in a wireless communication system and configured to communicate with a user equipment utilizing a first RAT. The method comprising receiving a message from the user equipment, wherein the message including measurement information collected by the user equipment in a second RAT, wherein the second RAT is different from the first RAT. The method further comprising forwarding the message to a receiving entity comprised in the wireless communication system.

In accordance with a third aspect of embodiments, a method in a receiving entity for reporting measurement is provided. The receiving entity is comprised in a wireless communication system and configured to communicate with a network node comprised in the wireless communication system. The method comprising receiving a message from a user equipment via the network node utilizing a first RAT, wherein the message includes measurement information collected by the user equipment in a second RAT, wherein the second RAT is different from the first RAT. The method further comprising retrieving the measurement information from the received message.

In accordance with a fourth aspect of embodiments, a user equipment for reporting measurement is provided. The user equipment is configured to communicate with a wireless communication system. The user equipment comprises a processing unit adapted to include measurement information in a message, wherein the measurement information is collected in a first RAT. The user equipment further comprises a transceiver adapted to transmit the message to a receiving entity comprised in the wireless communication system via a network node utilizing a second RAT, wherein the second RAT is different from the first RAT.

In accordance with a fifth aspect of embodiments, a network node for reporting measurement is provided. The network node is comprised in a wireless communication system and configured to communicate with a user equipment utilizing a first RAT. The network node comprises a transceiver adapted to receive a message from the user equipment, wherein the message includes measurement information collected by the user equipment in a second RAT, wherein the second RAT is different from the first RAT. The transceiver is further adapted to forward the message to a receiving entity comprised in the wireless communication system.

In accordance with a sixth aspect of embodiments, a receiving entity for reporting measurement is provided. The receiving entity is comprised in a wireless communication system and configured to communicate with a network node comprised in the wireless communication system. The receiving entity comprises a transceiver adapted to receive a message from a user equipment via the network node utilizing a first RAT, wherein the message includes measurement information collected by the user equipment in a second RAT, wherein the second RAT is different from the first RAT. The receiving entity further comprises a processing unit adapted to retrieve the measurement information from the received message.

An advantage of particular embodiments is that they provide a solution to the stated object which prevents losses of MDT measurement log reports when a UE has moved to another RAT than the RAT in which the measurements were collected in.

A further advantage of particular embodiments is that they provide a solution which prevents additional delays of receiving MDT reports due to handover to another RAT than the RAT in which the measurements were collected in, since it can be reported in the new RAT and does not need to wait for the UE coming back to the RAT in which the measurements were collected in.

Yet an advantage of particular embodiments is that the format of the measurement log reported by a UE is specific to the RAT in which the measurements were collected in. Yet another advantage of particular embodiments is that the network node that receives the measurement log may be able to use the measurement log for internal SON (Self-Optimizing/ Organizing Network) purpose. Yet another advantage of particular embodiments is that the network node that receives the measurement log may forward the measurement log to a receiving entity without needing to decode the content of the measurement log. Yet another advantage of particular embodiments is that when the UE enters a new RAT the network node may request delivery of an existing measurement log, before commanding the UE to start collecting measurements and storing a new measurement log in the new RAT. Yet another advantage of particular embodiments is that set of measurements collected by the UE in one RAT (below called RAT _co iiect) can in future be extended with new types of measurement, without impacting the implementation of the RAT to which UE reports the measurements (below called RAT _rep ort) .

Further advantages and features of embodiments will become apparent when reading the following detailed description in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding, reference is made to the following drawings and preferred embodiments.

Figure 1 illustrates the prior art procedure of reporting the measurement log from the user equipment to the network. Figure 2 shows an exemplary embodiment of a generic MDT measurement reporting structure for all RATs.

Figure 3 is a signaling diagram schematically illustrating the signaling according to exemplary embodiments. Figure 4a-4d show flowcharts of exemplary embodiments of a method in a user equipment for reporting measurements.

Figure 5 shows a flowchart of an exemplary embodiment of a method in a network node for reporting measurements.

Figure 6a-6c show flowcharts of exemplary embodiments of a method in a receiving entity for receiving measurement reports. Figures 7 is a block diagram illustrating the user equipment, the network node and the receiving entity according to embodiments.

DETAILED DESCRIPTION

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular sequences of steps and particular device configurations in order to provide a thorough understanding of the embodiments. It will be apparent to one skilled in the art that the embodiments may be practised in other embodiments that depart from these specific details. In the drawings, like reference signs refer to like elements.

Moreover, those skilled in the art will appreciate that the means and functions explained herein below may be implemented using software functioning in conjunction with a programmed microprocessor or general purpose computer, and/ or using an application specific integrated circuit

(ASIC). It will also be appreciated that while the current embodiments are primarily described in the form of methods and devices, the embodiments may also be embodied in a computer program product as well as a system comprising a computer processor and a memory coupled to the processor, wherein the memory is encoded with one or more programs that may perform the functions disclosed herein.

Embodiments are described herein by way of reference to particular example scenarios. Particular aspects are described in a non-limiting general context in relation to an LTE system, a GSM system and WCDMA system. It should though be noted that the invention and its exemplary embodiments may also be applied to other types of radio access networks for reporting measurement information.

In the following detailed description a number of embodiments are disclosed wherein the problem of reporting measurements in another RAT than in the

RAT in which the measurements were collected in, is addressed by a solution where a UE includes the measurement information collected in a first RAT in a message which is sent to a network node in a second RAT. The network node then forwards the message to a receiving entity without having to decode the actual content of the measurement log. This is done by introducing a decodable address (or addresses) field, such as an IP address and/ or other addressing information, and using a container structure where the actual measurement log as reported by the UE is placed. The container need not be understandable by the network node and could be of a message format used in the RAT where the UE collected the measurement log. Thus, there is no need to reformat the measurement results.

In the following detailed description the RAT in which the measurements are collected by the UE is denoted RAT _co uect and the RAT in which the measurement log is reported is denoted RAT _re port. It should be noted that

RATreport is a different radio access technology than the radio access technology RAT _co uect.

According to exemplary embodiments the message which is sent from the UE to the network node contains a measurement receiver address which is encoded according to the rules of the RAT in which the measurement log is reported by the UE i.e. RAT _rep ort. The message further comprises a RAT indicator which indicates the RAT in which measurements in the measurement log was collected by the UE i.e. RAT _co iiect. The RAT indicator may be encoded according to the rules of the RAT _re port. Moreover, the message may contain a measurement log that may be encoded according to the rules of the RATcouect.

The embodiments provide a solution where the reported measurement log is RAT-specific. The network node, e.g. , an eNodeB comprised in a LTE system or a RNC comprised in a WCDMA system, that receives the measurement log can use the log for internal SON (Self-Optimizing/ Organizing Network) purpose, such as optimising parameter settings (power levels, timers etc), correcting neighbouring cell lists and adjusting antenna propagations patterns. However, the network node may also forward the message comprising the measurement log to a receiving entity such as an OAM (Operation and Maintenance) Server. This may be performed without decoding the content of the measurement log. Furthermore, the embodiments provide the possibility for the network node to request delivery of an existing measurement log in the UE, before commanding the UE to start collecting a new measurement log when the UE has entered a new RAT.

A measurement report can contain a number of RAT- specific measurements and be sent from the UE to the network node using a control plane RRC (Radio Resource Control) message. In order to report the measurements in another RAT than in which the measurements were performed, there is a need to specify a format where the measurements that have been made in a first RAT, i.e. RAT _co uect can be received in a second RAT and that provides the network node in the second RAT, i.e. RAT _re port, with a possibility to understand what to do with it, i.e. to which receiving entity the measurement log should be forwarded.

Figure 2 illustrates an exemplary embodiment of a generic MDT measurement reporting message for all RATs in a wireless communication network that may be used by the UE to report the measurement logs to the network node. A message 20 comprises a header field 21 which is RAT specific, a measurement receiver address field 22 and a measurement container field 23. The header field 21 is encoded according to the rules of the second RAT in which the measurement log is reported by the UE, i.e. RATreport. Thus, the network node receiving the message 20 is able to understand from which RAT the message is sent. Furthermore, the header field may comprise a RAT indicator which indicates the RAT in which measurements in the measurement log was collected by the UE, i.e. RAT _co nect. The RAT indicator is encoded according to the rules of the second RAT in which the measurement log is reported by the UE, i.e. RATreport. The measurements performed by the UE are placed in the measurement container field 23, which content need not to be understood by the intermediate receiver, i.e. the network node in RAT _re port in which a report including the message 20 is received. However, for the network node to be able to forward the received message to the right place, the measurement receiver address field 22 is used. The measurement receiver address field 22 comprises an address of the receiving entity, e.g. an IP-address plus any other related identification needed. Both the measurement container field 23 and the measurement receiver address field 22 can be of variable lengths and thus may each one of them need a length indicator LI in certain embodiments. However, if the length is fixed, no such information is needed. The length indicators may be included in the measurement container field 23 and the measurement receiver address field 22, respectively, as shown in Figure 2. However, the length indicators LI may be placed in the header field 21 in some embodiments.

There could also be other ways of indicating the lengths of the container field 23 and the receiver address field 22, e.g., they could be of a fixed length and padding could be applied. Typically there would only be one measurement receiver address so the measurement receiver address field 22 would be of a fixed length, thus there would be no need for a specific length indicator for this field. For example, the Abstract Syntax Notation One (ASN. l) that describes data structures provides a set of formal rules for describing the structure of objects and may remove the need for a explicit length notation in the message content part (e.g. measurement results in the measurement report) by using a bit- or octet string notation, or other for describing the variable size of the RRC message and/ or container. In this case, in order for the receiving side, e.g. the receiving entity, to decode the variable message, it may be required to define a set of predefined sizes (e.g. a list of sizes), for example message container sizes of 1,2, ...n in number of octets. The UE then may select a size larger than or equal to octets fitting the content part of the report and add padding when needed.

In an exemplary embodiment, measurements performed in a wireless communication system such as LTE can be reported in a WCDMA or a GSM/EDGE system and then forwarded to the correct place such as an OAM functionality, a measurement collection center or a trace collection center and/ or to an eNodeB. Figure 3 is a signaling diagram schematically illustrating the signaling according to exemplary embodiments. A network node, e.g., an eNodeB, in a first RAT (RATcoiiect) , e.g., the RAT of Evolved Universal Terrestrial Radio Access Network (E-UTRAN), is comprised in a wireless communication system which communicates with and serves several UEs. The wireless communication system employs different RATs that overlap over a geographic area. The network node requests 30 a UE to start performing logging of measurement information. For example, the network node may request the UE to log downlink pilot signal strength measurements of serving cell or neighbour cell, downlink pilot signal quality measurements of serving cell or neighbour cell, GPS positioning data etc. The UE executes measurements and logs 31 the measurement information internally in a sequential manner, containing e.g. some hour of logged measurement information. However, the UE may not stay in one and the same RAT, i.e. the RATcoiiect, during the logging of measurement information. Previously described, the change of RAT is mainly related to network deployment and service provisioning. An existing operator's network is often a combination of several RATs and designed to work together in order to maximize the service offerings and geographical coverage area in a cost efficient way. Thus, during the logging of measurement information the UE may change RAT 32 e.g. by performing a handover. After the handover the UE communicates with and is served by another network node in the wireless communication system e.g. a RNC (Radio Network Controller), in a second RAT (RAT _rep ort) , e.g. the RAT of GSM (Global System for Mobile Communications). Moreover, when the UE has logged measurement information the UE indicates 33 to the network node in the RAT _re port that it has an available measurement log. The network node then determines 34 whether is wants to request the measurement log. If it determines to request the measurement log it sends 35 a request of delivery to the UE. Thereupon the UE delivers 36 the measurement log to the network node in accordance with embodiments described in the following. The network node may then forward 37 the received measurement log to an OAM (Operation and Maintenance) or similar server comprised in the wireless communication system. Figure 4a is a flowchart of a method in a UE according to embodiments. When the UE has collected measurement information in the measurement log in a first RAT, i.e. RAT _co iiect, and received a request to deliver the measurement log to a network node in a second RAT, i.e. RATreport, the UE starts preparing to deliver the measurement report. The UE includes 41 the logged measurement information in a message, wherein the measurement information is collected in RAT _co iiect. Then the UE transmits 42 the message to a receiving entity such as an OAM server or TCE (Trace Collection Entity) . The receiving entity is also comprised in the wireless communication system. Furthermore, in an exemplary embodiment the receiving entity may be the network node or comprised in the network node.

Moreover, the message is sent via the network node utilizing the RAT _re port. The message sent may be of a message format described in connection with Figure 2. In an exemplary embodiment, illustrated in Figure 4b, the UE introduces 43 a receiver address field in the message. The receiver address field comprises the address of the receiving entity and is possible to decode by at least the network node in the RAT _re port. The address may be e.g. an IP- address plus any other related identification. In a further exemplary embodiment illustrated in Figure 4c, the UE encapsulates 44 the measurement information in a container structure using a message format of the RATcoiiect. Thus, the content may not be understood by the intermediate receiver, i.e. the network node in RAT _rep ort. The UE may further introduce 45 a RAT indicator which indicates the RAT _co iiect in which the measurement information is collected, which is illustrated in Figure 4d. In this embodiment the UE further encodes 46 the RAT indicator using a message format of RAT _re port. Thus, the network node in the second RAT i.e. RATreport may use the encapsulated measurement information for internal SON purposes as previously described. Moreover, the network node in RAT _rep ort may route the encapsulated measurement information to different receiving entities based on the RAT indicator. This also allows the receiving entity to know how to decode the encapsulated measurement information.

Moreover, a pre-defined set of container sizes are configured in the UE and the UE may further select a container size of the pre-defined set of container sizes which fits the measurement information in the container structure. Furthermore, the container may have a length which is variable and may comprise a length indicator indicating the length of the container. Also the receiver address field may have a length which is variable and may comprise a length indicator indicating the length of the address field. The length indicators may in some embodiments be comprised in the RAT header as previously described.

Figure 5 is a flowchart of a method in a network node according to embodiments. The network node is comprised in the wireless communication system and configured to communicate with the UE utilizing a first RAT, i.e. RATreport, in accordance with previously described embodiments. The network node receives 51 a message from the UE upon request of delivery of the measurement report. The message includes measurement information collected in a second RAT, i.e. RATcoiiect. The network node forwards 52 the message to a receiving entity such as an OAM server or TCE comprised in the wireless communication system.

Figure 6a is a flowchart of a method in a receiving entity according to embodiments. The receiving entity is comprised in the wireless communication system and configured to communicate with a network node comprised in the wireless communication system in accordance with previously described embodiments. The receiving entity, e.g. an OAM server or TCE, receives 61 a message from a UE via the network node in a first RAT, i.e. RATreport. The message includes measurement information collected by the UE in a second RAT, i.e. RAT _co ii _e ct. The receiving entity retrieves 62 the measurement information from the received message. In an exemplary embodiment illustrated in Figure 6b the receiving entity decodes 63 a RAT indicator comprised in the message utilizing a message format of RAT _rep ort. The RAT indicator indicates which RAT, i.e. RATcoiiect, in which the measurement information is collected. In another exemplary embodiment, illustrated in Figure 6c, the receiving entity retrieves 64 the measurement information from a container structure using a message format of RATcoiiect indicated by the RAT indicator.

In the described embodiments, the RAT _re port may be implemented in a LTE system and the RATcoiiect is implemented in a WCDMA or a GSM/EDGE system. The LTE system and the WCDMA or GSM /EDGE system is comprised in the wireless communication system. As a further example, the RATYeport may be implemented in a WCDMA or a GSM/ EDGE system and the RATcoUect is implemented in a LTE system. The LTE system and the WCDMA or GSM /EDGE system is comprised in the wireless communication system.

Figure 7 is a schematic block diagram schematically illustrating an exemplary UE 701 that is configured to communicate with an exemplary network node 704 comprised in a wireless communication system 700. The wireless communication system 700 may further include an exemplary receiving entity 706. The UE 701, the network node 704 and the receiving entity 706 can be implemented using various components, both hardware and software. It should be noted that the wireless communication system may comprise several network nodes which each may serve several UEs and several receiving entities. However, for simplicity reasons only one UE, one network node and one receiving entity are illustrated in the figure. For example, the UE 701 may include a processor unit 702, one or more storage devices (not shown), an operating system (not shown) running on the processor unit 702 as well as an application which reports measurement information in the manner previously described. Additionally, the network node 704 may also include a processor unit (not shown) , one or more storage units (not shown), an operating system (not shown) running on the processor unit as well as an application which reports measurement information in the manner described above. Furthermore, the receiving entity may also comprise a processor unit 708, one or more storage units (not shown), an operating system (not shown) running on the processor unit as well as an application which receives measurement information reports in the manner described above. In an exemplary embodiment the UE 701 comprises a processing unit 702 adapted to include measurement information in a message, wherein the measurement information is collected in a first RAT i.e. RAT _co iiect. It further includes a transceiver 703 adapted to transmit the message to the receiving entity 706 via the network node 704 in a second RAT i.e. RAT _rep ort. The processing unit 702 may further be adapted to introduce a receiver address field in the message. The receiver address field comprises a receiver address which is possible to decode by at least the network node in RAT _rep ort. Moreover, the processing unit 702 may be adapted to encapsulate the measurement information in a container structure using a message format of RATcoiiect. The processing unit 702 of the UE may also be adapted to introduce a RAT indicator which indicates the RATcoiiect and encode the indicator using a message format of RAT _re port. In an embodiment wherein a pre-defined set of container sizes are configured in the UE, the processing unit 702 is adapted to select a container size of the pre-defined set of container sizes which fits the measurement information in the container structure.

In an exemplary embodiment the network node 704 comprises a transceiver 705 adapted to receive a message from the UE 701. The message includes measurement information collected by the UE 701 in RATcoiiect. The transceiver 705 is also adapted to forward the message to the receiving entity 706.

In an exemplary embodiment the receiving entity 706 comprises a transceiver 707 adapted to receive a message from a UE 701 via the network node 704 in RAT _rep ort. The message includes measurement information collected by the UE 701 in RAT _co iiect. The receiving entity 706 further includes a processing unit 708 adapted to retrieve the measurement information from the received message. Furthermore, in one embodiment the processing unit may be adapted to decode a RAT indicator comprised in the message utilizing a message format of the RATreport. The RAT indicator indicates the RATcoiiect in which the measurement information is collected. In yet another embodiment the processing unit 708 is further adapted to retrieve the measurement information from a container structure using a message format of the RATcoiiect indicated by the RAT indicator.

The embodiments may, of course, be carried out in other ways than those specifically set forth herein without departing from essential characteristics of the embodiments described. The present embodiments are to be considered in all respects as illustrative and not restrictive.