Abstract:
Method and communication network node for enabling a radio base station to adjust a Radio Access Network, RAN, capability within a RAN, such as handover or scheduling, dependent on a data transport characteristics of a backhaul network, such as data transfer rate, network delay and bandwidth. The RAN and the backhaul network are parts of a telecommunication network, and the first communication network node is arranged in the telecommunication network to communicate data between the RAN and a core network node in the telecommunication network. By acquiring knowledge of variations of transport characteristics in backhaul networks, RAN capabilities may be adjusted, e.g. by performing handover of UEs to other radio base stations which have better backhaul transport characteristics. Thereby, user experience for the users of the UE may be increased. In addition, an operator of the communication network may make better use of installed transport capacity.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates to adaption of radio capabilities in wireless communication networks, especially it relates to adaption of radio capabilities of Radio Access Networks in dependence of data transport characteristics of backhaul networks. 
       BACKGROUND 
       [0002]    Modern telecommunication networks are commonly divided in separate parts, which are defined as RAN (Radio Access Network), core network, and backhaul network. The RAN serves UEs (User Equipments) and provides users of the UEs with communication capabilities, by providing DL data from radio base stations to the UEs and UL data from the UEs to the radio base stations. The mobile core network is a central part of the telecommunication network and provides various services to the users who are connected by the RAN, e.g. telephony and data communication. The backhaul network is the intermediate connecting network, which connects the RAN to the mobile core network. 
         [0003]    In this description, the term “User Equipment” will be used to denote any suitable communication terminal adapted to communicate with a radio base station. A UE may be implemented as a mobile phone, a PDA (Personal Digital Assistant), a handheld computer, a laptop computer, etc. A “radio base station” may be implanted as a NodeB, an eNodeB, a repeater, etc. 
         [0004]    With reference to  FIG. 1 , which is a schematic block diagram, a communication scenario will now be described according to the prior art. 
         [0005]    A telecommunication network is illustrated in the figure and comprises a RAN where an 
         [0006]    RBS (Radio base station)  120  is present, a backhaul network where an RNC (Radio Network Controller)  100  and a core network node  140  are present, and a core network. The communication network nodes, i.e. the RBS  120 , the RNC  100  and the core network node  140  are connected to each other by communication links L. 
         [0007]    Typically, the RBS  120  comprises conventional functionality (illustrated with a box “RBS”) for downloading DL data to UEs and uploading UL data from the UEs, antennas (not shown), etc. The RNC  100  comprises conventional functionality (illustrated with a box “RNC”) for exchanging DL and UL data between a plurality of RBSs  120  and the core network node  140 . The core network node  140  comprises ordinary functionality (illustrated with a box “Core”) for distributing the DL and UL data between the RNC  100  and the core network. 
         [0008]    Traditionally, the RANs have been bottlenecks in the telecommunication networks, due to limited communication capabilities of the radio interface to the UEs. For instance, in communication systems using GSM (Groupe Special Mobile) or earlier RAN generations, the backhaul networks are often capable of providing services at higher data rates than the RANs are capable to deliver. 
         [0009]    However, with the emergence of services, new RAN technologies have been introduced which are capable of serving the UEs with increased data rates. For instance, UMTS (Universal 
         [0010]    Mobile Telecommunication System), LTE (Long Term Evolution) and LTE Advanced systems have been defined by the 3GPP (Third Generation Partnership Project), and enables UL/DL data to be exchanged at increased data rates. 
         [0011]    Today, the backhaul networks will not always be capable of delivering the desired data rates for communication of DL/UL data. For instance, this will be the case when backhaul links are affected by various disturbances, or when the installed backhaul capability is restricted due to aggregation of data traffic. When the users of the UEs performs services and the backhaul network is not capable of delivering the required data transfer rate, the users experience of the services may be that they are slow and/or time lagging, which may be perceived as annoying by the users. 
         [0012]    To upgrade the communication links in the backhaul networks, for instance by installing fibre optic cables as communication links, requires a reasonable amount of resources and is time consuming and expensive. 
         [0013]    Thus, there is a problem to devise a method for increasing user experience in telecommunication networks with restricted backhaul network characteristics. 
       SUMMARY 
       [0014]    It would be desirable to obtain improved user experience in telecommunication networks. It is an object of this disclosure to address at least any of the issues outlined above. Further, it is an object to provide a mechanism for adaption of RAN (Radio Access Network) capabilities in response to variations in transport characteristics of backhaul networks. These objects may be met by a method and an arrangement according to the attached independent claims. 
         [0015]    According to one aspect, a method performed by a first communication network node is provided for enabling a radio base station to adjust a Radio Access Network, RAN, capability within a RAN, such as handover or scheduling, dependent on a data transport characteristics of a backhaul network, such as data transfer rate, network delay and bandwidth. The RAN and the backhaul network are parts of a telecommunication network, and the first communication network node is arranged in the telecommunication network to communicate data between the RAN and a core network node in the telecommunication network. The method comprises to obtain, by a RAN Adaptation Selection unit of the first communication network node, information related to the data transport characteristics of the backhaul network. Furthermore, the method comprises to select by the RAN Adaptation Selection unit that the RAN capability will be adjusted, depending on the obtained information, and when it is selected the RAN capability will be adjusted, request a RAN Adaptation unit to adjust the RAN capability, the RAN Adaptation unit being comprised in a Radio Base Station serving the RAN. 
         [0016]    By acquiring knowledge of variations of transport characteristics in backhaul networks, RAN capabilities may be adjusted, e.g. by performing handover of UEs to other radio base stations which have better backhaul transport characteristics. Thereby, user experience for the users of the UE may be increased. In addition, an operator of the communication network may make better use of installed transport capacity. 
         [0017]    The method may be performed in a radio network controller, which obtains the information as a compiled backhaul characteristics value of at least one of: End-to-end measurements between the radio base station and the core network node, and link characteristics reports for communication links of the backhaul network, and wherein the compiled backhaul characteristics value is used as a basis when selecting that the RAN capability will be adjusted. 
         [0018]    The disclosed method may alternatively be performed in a radio base station, which may be adapted to decide or select to adjust its RAN capabilities, in dependence to obtained information of variations in backhaul transport characteristics. By compiling results from a plurality of measurements into a backhaul characteristics value, as well current variations of backhaul characteristics and trends of variations may into account when deciding or selecting to adjust RAN capabilities. Furthermore, operator policies and RAN reports may in addition be taken into account, which may achieve a further more flexible use of installed transport capacity. 
         [0019]    It is to be noted that according to another aspect, a corresponding communication network node which is adapted to perform the described method is also applicable. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0020]    The solution will now be described in more detail by means of exemplary embodiments and with reference to the accompanying drawings, in which: 
           [0021]      FIG. 1  is a schematic illustration of an arrangement in accordance with the prior art. 
           [0022]      FIG. 2  is a schematic illustration of an arrangement, according to a possible embodiment. 
           [0023]      FIG. 3  is a schematic illustration of a method, according to possible embodiments. 
           [0024]      FIGS. 4 a - b    are schematic illustrations of arrangements, according to possible embodiments. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    In telecommunication networks where RBSs (Radio Base Stations) are arranged to exchange data between RANs (Radio Access Networks) and a backhaul network, transport characteristics of the backhaul network may be restricted, even if the RANs are capable of serving a large quantity of UEs (User Equipment). 
         [0026]    Today, RAN transport capabilities are determined, but backhaul characteristics is not taken into account when managing UEs in the RANs, e.g. for handling handover, or scheduling. For instance, an RBS which has good RAN characteristics may serve more UEs than the backhaul network is capable to. The user&#39;s QoE (Quality of Experience will then not be satisfying. 
         [0027]    According to the proposed solution, communication network nodes will obtain information of backhaul characteristics, by performing various measurements of variations of backhaul characteristics, such as network delay, etc. With the proposed solution, RBSs which have restricted backhaul characteristics will be enabled to handover some UEs to less loaded RBSs, or influence its scheduling. By adjusting RAN capabilities in response to variations of backhaul capacities, the total load of the RBSs could be fairer, which give rise to a better QoE for the End-users. 
         [0028]    With reference to  FIG. 2 , which is a schematic block diagram, a communication network node  200  will now be described in accordance with one exemplifying embodiment. 
         [0029]    The communication network node  200  is implemented as an RNC (Radio Network Controller) in this embodiment. The RNC  200  is arranged in a backhaul network of a telecommunication network, where it is arranged to serve at least one radio base station  220 , and exchange UL (uplink) data and DL (downlink) data, between the RBSs (Radio Base Station) and a core network node  240 . The RNC  200  comprises RATC (RAN (Radio Access Network) Aggregation Transport Characteristics) units  202   a,    202   b,  which are adapted to receive measurement results of transport characteristics of the backhaul network from reporting units  206 ,  226 ,  246 , and compile the measurement results into a backhaul characteristics value. The backhaul characteristics value may be implemented as a numerical value, representing an overall status of the backhaul transport characteristics, e.g. in a scale “1-10”, where “10” indicates full capacity and “1” severely restricted backhaul transport characteristics, or values reporting summarized backhaul characteristics like used and available bandwidth, delay, jitter etc. for a specific RBS. 
         [0030]    In this embodiment, the reporting units  226 ,  246  are arranged to perform an End-to-End measurement of variations in delay for transmitted data in the backhaul network, according to TWAMP (Two-way Active Measurement Protocol). Other reporting units  206  are instead adapted to perform other measurements of variations for network delays and transport capacities, e.g. according to BART (Bandwidth Available in Real-Time), Transport timing interval for real-time service packets, ECN (Explicit Congestion Notification), CONEX (Partial Congestion Exposure), etc. 
         [0031]    A RAS (RAN (Radio Access Network) Adaption Selection) unit  204  is arranged in the RNC  200  and is adapted to decide or select that the RAN capabilities will be adjusted, depending on the obtained information, i.e. variations of backhaul transport characteristics. The RAS  204  sends a request to an RBS to adjust its RAN capabilities, depending on the backhaul characteristics value. For instance, such a request may indicate that the RBS will handover a number of UEs (User Equipments) to another RBS, or that scheduling will be adjusted for some UEs. Typically, the request is sent via a communication interface (not shown) between the RNC  200  and the RBS  220 . In the RBS  220 , a RAN adaptation unit  228  may be arranged to receive the request and handle the adjustment to be performed. Such a RAN Adaptation unit  228  will be further described below in another embodiment. Correspondingly, similar appropriate communication interfaces may be implemented in the RAN  200  to receive the measurement results from the reporting units  226 ,  246  of the RBS  220  and core network node  240 , respectively. 
         [0032]    In an alternative exemplifying embodiment, which is based on the above described embodiment, further parameters may be applied by the RAS  204 , when deciding or selecting that the RAN capabilities will be adjusted, e.g. pre-set operator policies by network operators, or RAN reports received from the RBS via the communication interface. 
         [0033]    The RNC  200  comprises further conventional functionality arranged in order to operate the RNC  200  properly, e.g. controllers, communication interfaces, various memories, etc. However, any functionality which is not necessary for the understanding of the proposed solution will not be further discussed in this embodiment. 
         [0034]    By obtaining information from a plurality of measurements of parameters representing backhaul characteristics, various variations of the transport characteristics of the backhaul network may be taken into account for forming an overall estimation of the backhaul characteristics. For instance, as well fast variations of delays and data rates and ongoing trends will together form a reliable estimation. 
         [0035]    Even if the communication network node  200  of the described embodiments is implemented as an RNC and the communication network is a HSPA (High speed packet access) network in this exemplary embodiment, the present solution is not limited thereto. The communication network node  200  may, alternatively, be implemented as any suitable communication network node in a suitable communication network. For instance, the communication network node may be implemented as an eNodeB (evolved Node B) in an LTE (Long Term Evolution) communication network, or a suitable communication network node in a suitable radio access technology, e.g. WiFi (Wireless Fidelity), GSM (Groupe Special Mobile), CDMA (Code Division Multiple Access), SC-TDMA (Synchronous Code Time Divided Multiple Access), WiMax (Worldwide Interoperability for Microwave Access). 
         [0036]    With reference to  FIG. 3 , which is a schematic flow chart, a method in a communication network node will now be described in accordance with one exemplifying embodiment. 
         [0037]    The communication network node is an RNC (Radio Network Controller) which is arranged in a backhaul network of a telecommunication network, where it is arranged to serve RBSs (Radio Base Stations), and exchange UL (uplink) data and DL (downlink) data, between the RBSs and a core network node. 
         [0038]    In a first action  300 , the RNC obtains information related to transport characteristics of the backhaul network. In this embodiment, the information is obtained as a backhaul characteristics value from another communication network node, e.g. the core network node or the RBS, which has compiled results from measurement of various backhaul transport characteristics into the backhaul characteristics value. 
         [0039]    In a subsequent action  306 , the RNC decides or selects whether RAN capabilities of RBSs will be adjusted, depending on the backhaul characteristics value. In this embodiment the backhaul characteristics value is compared with a pre-set value and depending on if the backhaul characteristics value is below or above the pre-set value, the RNC selects to either request the RBS to adjust its RAN capabilities, in a following action  308 , or proceed to obtain information according to the action  300 . 
         [0040]    The RBS will then, in a following action  310 , adjust its RAN capabilities in upon reception of the request. The action  310  (dashed line) is performed by the RBS and not the RNC, but in order to enable the understanding of the solution it is shown in the figure. 
         [0041]    In an alternative exemplifying embodiment which is based on the embodiment described above, the information of backhaul variations is instead obtained as various measurement results of backhaul characteristics, in the action  300 . Then the RNC compiles the obtained measurement results into a backhaul characteristics value, in an intermediate action  302 , performed after action  300  but before action  306 . 
         [0042]    It is to be noted that for both the above described embodiments, also various management parameters may be taken into account when deciding or selecting whether or not to adjust the RAN capabilities. For instance, in an intermediate action  304 , performed after action  300  but before action  306 , the RNC obtains a RAN report from the RBS, or gets an operator policy set. This alternative embodiment differs further in that the RNC takes the RAN reports and/or the operator policy in account when deciding or selecting in action  306 . 
         [0043]    With reference to  FIGS. 4 a - b   , which are schematic block diagrams, two communication network nodes  200  will now be described in accordance with further exemplifying embodiments. 
         [0044]    These embodiments are two alternative embodiments which are related to the embodiment described in accordance with  FIG. 2 . Therefore, and in order to simplify the understanding of the disclosed concept, the same reference numbers will be used where appropriate. The communication network nodes  220  are implemented as eNodeBs,  220 , i.e. RBSs of LTE (Long Term Evolution) communication networks. In the figures it is illustrated that the eNodeBs  220  serve UEs (User Equipments), which are associated to the eNodeBs via RANs. Typically, the eNodeBs  220  also comprise conventional functionality to operate properly, which is illustrated with a control unit and a communication interface, respectively. However, in order to simplify the understanding such conventional functionality has been omitted in this description. 
         [0045]    Analogously, with the RNC  200  and the RBS  220  ( FIG. 2 ), the eNodeBs  220  comprises a RAS  224  ( 204  in  FIG. 2 ), a reporting unit  226  ( 206 ,  226  in  FIG. 2 ), and a RAN Adaptation unit  228  ( 228  in  FIG. 2 ). Furthermore, the eNodeB  220  which is illustrated in  FIG. 4 a    comprises an RATC  222  ( 202   a,    202   b  in  FIG. 2 ). The eNodeB  220  which is illustrated in  FIG. 4 b    lacks RATC, but is adapted to apply RATC functionality  242  of another communication network node, e.g. a core network node  240 . 
         [0046]    Regarding  FIG. 4 a   , the RATC  222  is arranged to obtain measurement results of variations of backhaul characteristics from reporting units  226 ,  246 , and compile into a backhaul characteristics value. The RAS  224  is arranged to decide or select whether or not the RAN capability of the eNodeB  220  will be adjusted, in response to the backhaul characteristics value. The RAS  224  is arranged to request the RAN Adaptation unit  228  to adjust the RAN capabilities of the eNodeB  220 . 
         [0047]    Regarding  FIG. 4 b   , the RAS  224  is arranged to receive a backhaul characteristics value from an RATC  242  which is arranged in the core network node  240 , where the backhaul characteristics value has been compiled of measurement results of variations of backhaul characteristics. The measurement results originates from reporting units  226 ,  246  arranged in various communication network nodes, e.g. the eNodeB  220  and the core network node  240 , respectively. 
         [0048]    It is to be noted that the communication network nodes of the described exemplifying embodiments are described in a non-limiting manner. However, a designer may select to implement further communication network nodes between the described communication network nodes within the described concept, such that the measurement results and backhaul characteristics values are obtained via these further communication network nodes. Moreover, the figures and embodiments illustrate a plurality of functional units in a non-limiting manner. However, a physical implementation of the proposed communication network nodes may be performed alternatively within the disclosed concept. For instance, functionality of a specific illustrated unit may be implemented in another suitable unit when put into practice. 
         [0049]    Reference throughout the specification to “one embodiment” or “an embodiment” is used to mean that a particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment. Thus, the appearance of the expressions “in one embodiment” or “in an embodiment” in various places throughout the specification are not necessarily referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or several embodiments. Although the present invention has been described above with reference to specific embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the invention is limited only by the accompanying claims and other embodiments than the specific above are equally possible within the scope of the appended claims. Moreover, it should be appreciated that the terms “comprise/comprises” or “include/includes”, as used herein, do not exclude the presence of other elements or steps. Furthermore, although individual features may be included in different claims, these may possibly advantageously be combined, and the inclusion of different claims does not imply that a combination of features is not feasible and/or advantageous. In addition, singular references do not exclude a plurality. Finally, reference signs in the claims are provided merely as a clarifying example and should not be construed as limiting the scope of the claims in any way. 
         [0050]    The scope is generally defined by the following independent claims. Exemplifying embodiments are defined by the dependent claims.